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Antifreeze Admixtures for Concrete during Cold Weather Concreting

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Freezing reduces strength of concrete by 20 to 40 % when fresh concrete 
is subjected to freezing. Antifreeze admixtures of concrete, its 
properties and uses in cold weather concreting are discussed.<br />
<br />
The
 resistance of the fresh concrete against the freeze and thaw cycle is 
given by the durability factor which is also lowered by 40 to 60%. There
 is 70% decrease in the bond between the reinforcement and the concrete 
that is normally cured.<br />
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<tr><td style="text-align: center;"><img alt=" Cold Weather Concreting_engineersdaily.com" border="0" data-original-height="359" data-original-width="644" src="https://3.bp.blogspot.com/-tbgWA0k1rlc/WnSmbmiRAAI/AAAAAAAAHa4/GcoDI1ZE3FgPuwj8NKE7PC1LK428Cq0fACLcBGAs/s1600/antifreeze-admixture-for-concrete.jpg" title=" Cold Weather Concreting_engineersdaily.com" /></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><b><span style="font-size: small;"> Cold </span></b><b><span style="font-size: small;"><b><span style="font-size: small;">Weather </span></b>Concreting</span></b></td></tr>
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Hence it is very essential during the concreting in cold weather conditions to ensure that the concrete will not undergo freezing in its plastic state.<br />
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There are two methods for carrying out cold weather concreting:<br />
<ol>
<li>Provision of normal ambient temperatures for the concrete. This can be done through the heating of the concrete ingredients or bley providing heating enclosures.</li>
<li>The addition of chemical admixtures.</li>
</ol>
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<h3>
<span style="font-size: large;"><span style="color: #cc0000;">Conventional Chemical Admixtures in Cold Weather Concrete</span></span></h3>
<h3>
<span style="font-size: large;"><span style="color: #cc0000;"> </span></span></h3>
Conventional concrete used calcium chloride as <a href="http://www.engineersdaily.com/2013/08/introduction-to-chemical-admixtures.html">accelerating admixtures</a> to offset the retarding effects of slow hydration of concrete in low temperatures. This admixture is not effective below the freezing temperatures.<br />
<br />
This is found to be a drawback in the conventional form of admixtures. Hence, for arctic weather conditions, special admixtures are necessary. One such is antifreeze admixtures.<br />
Antifreeze Admixtures for Concrete<br />
<br />
The antifreeze admixtures affect the physical condition of the mix water used in the concreting. These can depress the freezing point of the water to a large extent and can be used in temperatures lesser than -30 degrees Celsius. This can enable the extension of the period of the construction activity.</div>
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<h3>
<span style="color: #3d85c6;">Chemical Composition and Action of Antifreeze Admixtures</span></h3>
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There are two groups of antifreeze admixtures that provide the characteristics of antifreeze and the accelerated setting and hardening properties.<br />
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They are:<br />
<br />
<h3>
<span style="font-size: small;"><b>1. First Group</b></span></h3>
<br />
This includes chemicals, weak electrolytes, sodium nitrite, sodium chloride and non-electrolytic organic compounds which lower the freezing point of the water used in the concrete. But these group acts as weak accelerators to promote the setting and hardening.<br />
<br />
<h3>
<span style="font-size: small;"><b>2. Second Group</b></span></h3>
<br />
These include binary as well as ternary admixtures which contains potash and additives based on calcium chloride, sodium nitrite, calcium chloride with sodium nitrite, calcium nitrite -nitrate-urea and other chemicals.<br />
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These have effective antifreeze properties and accelerating property to promote the setting and hardening. These are used in larger dosages compared to that of conventional admixtures.<br />
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One such example is the use of 8% of sodium nitrite to keep the liquid at a temperature of -15-degree Celsius.<br />
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These admixtures function by lowering the liquid phase freezing point and by accelerating the cement hydration at the freezing temperatures.<br />
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Based on the dosage in the mixture, the non-chloride admixture enables the mix (concrete or the mortar) to be placed at sub-freezing temperatures. This hence reduces the need of protective measures required during the cold weathering works.<br />
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The method improves the quality of the concrete and as it facilitates early setting, early <a href="http://www.engineersdaily.com/2016/04/considerations-for-concrete-formwork-design.html">stripping of formworks</a> can also be carried out. This helps in the reuse of the form within a small duration and hence speed up the construction.<br />
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The table-1 shows the significant difference is strength gain at 3, 7 and 28 days for plain concrete and antifreeze admixture used concrete.<br />
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<h3>
<span style="color: #3d85c6;">Table.1: Concrete Compressive strength with and without antifreeze admixture</span></h3>
<h3>
<span style="color: #3d85c6;"> </span></h3>
<b><span style="font-size: small;">(As per Ratinov and Rosenburg)</span></b><br />
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<table align="center" style="border-collapse: collapse; border-spacing: 0px; text-align: center;"><tbody>
<tr><th style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; font-weight: bold; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">Property</th><th style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; font-weight: bold; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">Plain Concrete</th><th style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; font-weight: bold; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">Freeze-protection Admixture</th></tr>
<tr><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">Set time (-4 degree Celsius)</td><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">–</td><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">–</td></tr>
<tr><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">Compressive strength (MPa)</td><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;"><br /></td><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;"><br /></td></tr>
<tr><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">-4 degree Celsius (3 days)</td><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">3.4</td><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">9.24</td></tr>
<tr><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">-10 degree Celsius (7 days)</td><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">8.3</td><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">39.3</td></tr>
<tr><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">-10 degree Celsius (28 days)</td><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">18.1</td><td style="border-style: solid; border-width: 1px; font-family: "arial",sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; text-align: center; word-break: normal;">49.9</td></tr>
</tbody></table>
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<br />
<br />
It is possible for the incorporation of other admixtures that contains superplasticizers to be incorporated with the antifreeze admixtures. The main advantage of such combination is that in totality there will be a reduction of water.<br />
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The water reduction will reduce the freezable free water content in the mix. This freezable water content is the one that serves as the heat sink for the heat liberated by the initial hydration reactions. This will hence reduce the number of antifreeze admixtures.<br />
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<h3>
<span style="color: #6fa8dc;">Selection of Antifreeze admixtures</span></h3>
<br />
The factors based on which the selection of antifreeze admixtures is carried out are: <br />
<ol>
<li>The type of structure</li>
<li>The operating Conditions</li>
<li>Protecting methods employed in winter concreting</li>
<li>Cement brand and aggregate types</li>
</ol>
<br />
A laboratory test must be carried out with the operating materials and the dosage of antifreeze admixtures that are intended to be used in the field.<br />
<br />
The incorporation of other admixtures like retarders, superplasticizers with antifreeze admixtures is not restricted in cold weather concreting. The dosage of all the admixture that are used must be established experimentally.<br />
<br />
<h3>
<span style="color: #3d85c6;">Application and Advantages of Antifreeze admixtures</span></h3>
<br />
The antifreeze admixtures are technologically simple and beneficial for cold weather concreting. The admixture helps in improving the cohesiveness, cold joint minimizations, sand streaking, and plasticity. These are estimated to provide large cost saving than other methods of steam curing or concrete enclosures.<br />
<br />
The combination of antifreeze agents with water reducing agents or air-entraining agents will help in increasing the resistance of concrete towards the frost action and corrosion.<br />
<br /></div>

Antifreeze Admixtures for Concrete during Cold Weather Concreting

Freezing reduces strength of concrete by 20 to 40 % when fresh concrete is subjected to freezing. Antifreeze admixtures of concrete, its ...

Materials Used for Bridge Construction

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<h2>
<span style="color: #cc0000;"><b><span style="font-size: large;">Materials Used in Bridge Construction</span></b></span></h2>
<br />
Stones, Timber, Concrete and Steel are the traditional materials that are used to carry out bridge construction. During the initial period, timber and stones were used in the construction, as they are directly obtained from nature and easily available.<br />
<br />
Brick was used as a subgroup construction material along with stone construction. Stones as construction materials were very popular because of its durable properties. Many historic bridges made from stones are still present as a symbol of past architectural culture.<br />
<br />
But some of the timber bridge have been washed away or are in the stage of degradation due to their exposure to the environmental conditions.<br />
<br />
As time passed, the bridge construction has undergone more development in terms of materials used for construction than based on the bridge technology.<br />
<br />
The concrete and steel are manmade refined materials. The bridge construction with these artificial materials can be called the second period of the bridge engineering. This hence was the start of modern bridge engineering technology.<br />
<br />
Modern bridges make use of concrete or steel or in combination. Different other innovative materials are being developed so that they can well suit with the bridge terminologies.<br />
<br />
Incorporation of fibers which comes in the category of high strength gaining materials is now incorporated for the construction of bridges. These materials are also used in order to strengthen the existing bridges.</div>
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<div style="text-align: justify;">
<h2>
<span style="font-size: large;"><span style="color: #3d85c6;">
Stones for Bridge Construction</span></span></h2>
<br />
For a long time in the history, the stone has been used in and as a single form. They are mainly used in the form of arches. This is because they possess higher compressive strength.<br />
<br />
The use of stones gave the engineers ease of constructing bridges that are aesthetically top and high in durability.<br />
<br />
When considering the history of bridge construction with stones, the Romans were the greatest builders of bridges with stones. They had a clear idea and understanding of the load over bridge, the geometry as well as the material properties. This made them construct very larger span bridges when compared with any other bridge construction during that period.<br />
<br />
The period was also competitive for Chinese. China had also developed large bridge called the famous Zhuzhou Bridge. The Zhuzhou bridge is the world’s known oldest open-spandrel, stone and segmental arch bridge. Nihonbashi is the most famous stone bridge in Japan. This is called as the Japan Bridge.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><img alt="The Zhuzhou bridge, China_engineersdaily.com" border="0" data-original-height="419" data-original-width="689" height="388" src="https://2.bp.blogspot.com/-Hv2u73nDmGo/WmtWc_n32OI/AAAAAAAAHaU/xR4trNcwMxA3i72SxokvnanV1c1lRG-8gCLcBGAs/s640/zhazhou-bridge.jpg" title="The Zhuzhou bridge, China_engineersdaily.com" width="640" /></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><b>Fig.1: The Zhuzhou bridge, China</b></span></td></tr>
</tbody></table>
<br />
With time, the stone bridges have proved most efficient and economical due to the durability and low maintenance guaranty it provides throughout its life period.</div>
<div style="text-align: justify;">
<br />
<h2>
<span style="font-size: large;"><b><span style="font-weight: normal;"><span style="color: #3d85c6;">
Timber or Wood for Bridge Construction</span></span></b></span></h2>
<br />
The wood material was used highly in the construction of bridges, unlike today, where it is used for the construction of building works and related. Nowadays, steel and concrete grant a higher range of work flexibility, that the use of wood and timber for mega works diminished.<br />
<br />
But, there are innovations related to the preservation of wood, which has helped to increase the demand of wood in structures.<br />
<br />
Wood as an engineering material has the advantage of high toughness and renewable in nature. They are obtained directly from nature and hence are environmentally friendly.<br />
<br />
The low density of wood makes it gain high specific strength. They have an appreciable strength value with a lower value of density. This property makes them be transported easily.<br />
<br />
Some of the disadvantages related to wood as a construction material are that it is:</div>
<div style="text-align: justify;">
<ul>
<li>Highly Anisotropic in Nature</li>
<li>Susceptible to termites, infestations, and woodworm</li>
<li>Highly combustible</li>
<li>Susceptible to rot and disease</li>
<li>Cannot be used for High temperature</li>
</ul>
<br />
There are a variety of timber bridges around the world. Figure-2 shows the Mathematical Bridge located in Cambridge. Another bridge is the Togetsu-Kyo Bridge over the Katsura River in Kyoto.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-0RYEM4P4Zlg/WmtWcTjV0pI/AAAAAAAAHaM/L5LUhcBmDqEf7wB-PLsZSN0onLnrdhxDACLcBGAs/s1600/mathematical-bridge-cambridge.jpg" style="margin-left: auto; margin-right: auto;"><img alt="The Mathematical Bridge, Cambridge_engineersdaily.com" border="0" data-original-height="327" data-original-width="675" height="310" src="https://1.bp.blogspot.com/-0RYEM4P4Zlg/WmtWcTjV0pI/AAAAAAAAHaM/L5LUhcBmDqEf7wB-PLsZSN0onLnrdhxDACLcBGAs/s640/mathematical-bridge-cambridge.jpg" title="The Mathematical Bridge, Cambridge_engineersdaily.com" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><b><span style="font-size: small;">Fig.2: The Mathematical Bridge, Cambridge</span></b></td></tr>
</tbody></table>
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><img alt="The Togetsu-Kyo Bridge, Japan_engineersdaily.com" border="0" data-original-height="240" data-original-width="624" height="246" src="https://2.bp.blogspot.com/--w3CfUjeHtQ/WmtWcv9rl_I/AAAAAAAAHaQ/YUz8nT3dJDAlRj10Z2ListuUfkhCG05zwCLcBGAs/s640/togetsu-kyo-bridge-japan.jpg" title="The Togetsu-Kyo Bridge, Japan_engineersdaily.com" width="640" /></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><b>Fig.3. The Togetsu-Kyo Bridge, Japan</b></span></td></tr>
</tbody></table>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody></tbody></table>
<h2>
<span style="font-size: large;"><span style="color: #3d85c6;">
Steel for Bridge Construction</span></span></h2>
<h3>
 </h3>
Steel gain high strength when compared with any other material. This makes its suitable for the construction of bridges with longer span. We know that steel is a combination of alloys of iron and other elements, mainly carbon.<br />
<br />
Based on the amount and variation of the elements, the properties of the same is altered accordingly. The properties of tensile strength, ductility and hardness are influenced by the change in its constitution.<br />
<br />
The steel used for normal construction have several hundred Mega Pascal strength. This strength is almost 10 times greater than the compressive and the tensile strength obtained from a normal concrete mix.<br />
<br />
The major inbuilt property of steel is the ductility property. This is the deformation capability before the final breakage tends to happen. This property of steel is an important criterion in the design of structures.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-5P-VpOp30Lk/WmtWcZwEfEI/AAAAAAAAHaI/tZUrMuAIllEv-FS1CJ4774wZVxNI1WzIACLcBGAs/s1600/hachimanbashi-bridge.jpg" style="margin-left: auto; margin-right: auto;"><img alt="The Hachimanbashi Bridge_engineersdaily.com" border="0" data-original-height="320" data-original-width="600" height="340" src="https://3.bp.blogspot.com/-5P-VpOp30Lk/WmtWcZwEfEI/AAAAAAAAHaI/tZUrMuAIllEv-FS1CJ4774wZVxNI1WzIACLcBGAs/s640/hachimanbashi-bridge.jpg" title="The Hachimanbashi Bridge_engineersdaily.com" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><b><span style="font-size: small;">Fig.4. The Hachimanbashi Bridge</span></b></td></tr>
</tbody></table>
<br />
The first iron bridge, Danjobashi Bridge which was built in 1878 in Japan. The figure-4 below shows the Danjobashi Bridge. Danjobashi Bridge was relocated to the present location and was named as Hachimanbashi Bridge in 1929.<br />
<br />
It has great historical and technical value as a modern bridge. The bridge was honored by the American Society of Civil Engineers in the year 1989.<br />
<br />
The chemical composition and the method of manufacture determines the properties of structural steel. The main properties that are to be specified by the bridge designers when it is required to specify the products are:<br />
<ul>
<li>Strength</li>
<li>Toughness</li>
<li>Ductility</li>
<li>Durability</li>
<li>Weldability</li>
</ul>
<br />
When we mention the steel strength, it implies both the yield and the tensile strength. As the structures are more designed in the elastic stage, it is very essential to know the value of yield strength.<br />
<br />
Yield strength is mostly used as it is more specified in the design codes. In Japan, the code recommended is designed for ultimate strength. For example, SS400 designated by the ultimate strength of 400MPa. This is an exception.<br />
<br />
The property of ductility is very much relied on by designers and engineers for the design aspects related to the bolt group designs and the distribution of stress at the ultimate limit state conditions. Another important property is the corrosion resistance by the use of weathering steel.</div>
<div style="text-align: justify;">
<br />
<h2>
<span style="font-size: large;"><span style="color: #3d85c6;">
Concrete for Bridge Construction</span></span></h2>
<br />
Most of the modern bridge construction make use of concrete as the primary material. The concrete is good in compression and weak in tensile strength. The reinforced concrete structures are the remedy put forward for this problem.<br />
<br />
The concrete tends to have a constant value of modulus of elasticity at lower stress levels. But this value decreases at a higher stress condition. This will welcome the formation of cracks and later their propagation.<br />
<br />
Other factors to which concrete is susceptible are the thermal expansion and shrinkage effects. Creep is formed in concrete due to long time stress on it.<br />
<br />
The mechanical properties of concrete are determined by the compressive strength of concrete.<br />
<br />
The reinforced or the prestressed concrete is used for the construction of bridges. The reinforcement in R.C.C provides the ductility property to the structure. Nowadays, ductility reinforcement is provided as an additional requirement mainly in the earthquake resistant construction.<br />
<br />
RCC is nowadays made from steel, polymer or other combination of composite materials. Much sustainable materials is available that can take the role of cement. This is a new innovation in sustainable bridge construction.<br />
<br />
When compared with RCC bridge construction, prestressed concrete is the most preferred and employed. A pre-compressive force is induced in the concrete with the help of high strength steel tendons before the actual service load.<br />
<br />
Hence this compressive stress will resist the tensile stress that is coming during the actual load conditions. The prestress is induced in concrete either by means of post tensioning or by means of pretensioning the steel reinforcement.<br />
<br />
Many disadvantages of normal reinforced concrete like strength limitations, heavy structures, building difficulty is solved using prestressed concrete.<br />
<br />
Also Read: <a href="http://www.engineersdaily.com/2017/11/dutch-inaugurate-3d-printed-reinforced-concrete-bridge-designed-by-tu-eindhoven.html" target="_blank"><span style="color: blue;"><span style="font-weight: normal;"></span>Dutch inaugurate the 3D Printed Reinforced Concrete Bridge Designed by Technical University of Eindhoven </span></a><br />
<br /></div>
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<h2>
<span style="font-size: large;"><span style="color: #3d85c6;">
Composite Materials in Bridge Construction</span></span></h2>
<h3>
 </h3>
</div>
<div style="text-align: justify;">
Composite materials are developed and used for both the construction of new bridges as well as for the rehabilitation purposes.<br />
<br />
Fiber reinforced plastic is one such material which is a polymer matrix. This is reinforced with fibers which can be either glass or carbon. These materials are light in weight, durable, high strength giving and ductile in nature.<br />
<br />
New solution and materials are encouraged due to the problems of deterioration the steel and concrete bridges are facing.<br />
<br />
Another material is the reactive powder concrete (RPC ) that was developed in Korea. This material is a form of high performance concrete that is reinforced with steel fibers. This mix will help to make slender columns for bridges of a longer span. This also guarantees durability extensively.<br />
<br />
Composite materials are used in the repair of bridge columns and any other supporting elements to improve the ductility and the resistance against the seismic force.<br />
<br />
Epoxy impregnated fiberglass are used to cover the column (columns that are non-ductile in nature). This is an alternative for the steel jacket technique.<br />
<br /></div>

Materials Used for Bridge Construction

Materials Used in Bridge Construction Stones, Timber, Concrete and Steel are the traditional materials that are used to carry out bridge...

Principle of Least Squares Applied to Surveying

<b><span style="color: #cc0000; font-size: large;">1. Introduction</span></b><br />
<b><span style="color: #cc0000; font-size: large;"><br /></span></b>
<div style="text-align: justify;">
‘<i><b>Least squares</b></i>’ is a powerful statistical technique that may be used for ‘<b><i>adjusting</i></b>’ or estimating the coordinates in <a href="http://www.engineersdaily.com/2014/03/book-engineering-surveying-5th-edition-schofield.html" target="_blank">survey</a> control networks. The term adjustment is one in popular usage but it does not have any proper statistical meaning. A better term is ‘least squares estimation’ since nothing, especially observations, are actually adjusted. Rather, coordinates are estimated from the evidence provided by the observations.</div>
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<br /></div>
<div style="text-align: justify;">
The great advantage of least squares over all the methods of estimation, such as traverse adjustments, is that least squares is mathematically and statistically justifiable and, as such, is a fully rigorous method.</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
It can be applied to any over determined network, but has the further advantage that it can be used on one-, two- and three-dimensional networks.A by-product of the least squares solution is a set of statistical statements about the quality of the solution. These statistical statements may take the form of standard errors of the computed coordinates, error ellipses or ellipsoids describing the uncertainty of a position in two or three dimensions, standard errors of observations derived from the computed coordinates and other meaningful statistics described later.</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
The major practical drawback with least squares is that unless the network has only a small number of unknown points, or has very few redundant observations, the amount of arithmetic manipulation makes the method impractical without the aid of a computer and appropriate software.</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
The examples and exercises in this material use very small networks in order to minimize the computational effort for the reader, while demonstrating the principles. Real survey networks are usually very much larger.</div>
<div style="text-align: justify;">
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A‘<b><i>residual</i></b>’ may be thought of as the difference between a computed and an observed value. For example, if in the observation and estimation of a network, a particular angle was observed to be 30°0' 0'' and after adjustment of the network the same angle computed from the adjusted coordinates was 30° 0' 20'', then the residual associated with that observation would be 20''. In other words:</div>
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<b>computed value − observed value = residual</b></div>
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Any estimation of an over determined network is going to involve some change to the observations to make them fit the adjusted coordinates of the control points. The best estimation technique is the one where the observations are in best agreement with the coordinates computed from them. In least squares, at its simplest, the best agreement is achieved by minimizing the sum of the squares of the weighted residuals of all the observations.</div>
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<b><span style="color: #cc0000; font-size: large;">2. Least squares applied to engineering</span></b></h2>
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In practical <a href="http://www.engineersdaily.com/2017/11/what-is-surveying.html" target="_blank">survey</a> networks, it is usual to observe more than the strict minimum number of observations required to solve for the coordinates of the unknown points. The extra observations are ‘<b><i>redundant</i></b>’ and can be used to provide an ‘<b><i>independent check</i></b>’ but all the observations can be incorporated into the solution of the network if the solution is by least squares.</div>
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All observations have errors so any practical set of observations will not perfectly fit any chosen set of coordinates for the unknown points.</div>
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Some observations will be of a better quality than others. For example, an angle observed with a 1'' theodolite should be more precise than one observed with a 20'' instrument. The weight applied to an observation, and hence to its residual, is a function of the previously assessed quality of the observation.</div>
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In the above example the angle observed with a 1" theodolite would have a much greater weight than one observed with a 20" theodolite. How weights are calculated and used will be described later.</div>
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If all the observations are to be used, then they will have to be ‘<b><i>adjusted</i></b>’ so that they fit with the computed network. The principle of least squares applied to surveying is that the sum of the squares of the weighted residuals must be a minimum.</div>
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<b><i>2.1 A simple illustration</i></b></h3>
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A locus line is the line that a point may lie on and may be defined by a single observation. Figure1(a), (b) and (c) show the locus lines associated with an angle observed at a known point to an unknown point, a distance measured between a known point and an unknown point and an angle observed at an unknown point between two known points respectively. In each case the locus line is the dotted line. In each case all that can be concluded from the individual observation is that the unknown point lies somewhere on the dotted line, but not where it lies.</div>
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-zNvrj5fstLM/WmMkSia6OwI/AAAAAAAAHZg/VbkY1eGcjug5jWIG3ffIM2YbKNkfcY_yACLcBGAs/s1600/least_squares%2528www.engineersdaily.com%25291.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Principle of Least Squares applied to Surveying" border="0" data-original-height="455" data-original-width="1417" height="204" src="https://4.bp.blogspot.com/-zNvrj5fstLM/WmMkSia6OwI/AAAAAAAAHZg/VbkY1eGcjug5jWIG3ffIM2YbKNkfcY_yACLcBGAs/s640/least_squares%2528www.engineersdaily.com%25291.png" title="Principle of Least Squares applied to Surveying" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><b>Figure 1 Locus lines</b></span></td></tr>
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-Nufiy5KdsP0/WmMkg3S3jZI/AAAAAAAAHZk/GkY4mwh30b4sGtDi6TulQLdmvq2TJZKVgCLcBGAs/s1600/least_squares%2528www.engineersdaily.com%25292.png" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img alt="Principle of Least Squares applied to Surveying" border="0" data-original-height="635" data-original-width="645" height="315" src="https://1.bp.blogspot.com/-Nufiy5KdsP0/WmMkg3S3jZI/AAAAAAAAHZk/GkY4mwh30b4sGtDi6TulQLdmvq2TJZKVgCLcBGAs/s320/least_squares%2528www.engineersdaily.com%25292.png" title="Principle of Least Squares applied to Surveying" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td class="tr-caption" style="font-size: 12.8px;"><span style="font-size: small;"><b>Figure 2 Intersection of locus lines</b></span></td></tr>
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In the following, the coordinates of new point P are to be determined from horizontal angles observed at known points A, B, C and D as in Figure 2(a). Each observation may be thought of as defining a locus line. For example, if only the horizontal angle at A had been observed then all that could be said about P would be that it lies somewhere on the locus line from A towards P and there could be no solution for the coordinates of P. With the horizontal angles at A and B there are two locus lines, from A towards P and from B towards P. The two lines cross at a unique point and if the observations had been perfect then the unique point would be exactly at P. But since observations are never perfect when the <a href="http://www.engineersdaily.com/2014/04/azimuths-and-bearings-in-surveying.html" target="_blank">horizontal angles</a> observed at C and D are added to the solution the four locus lines do not all cross at the same point and the mismatch gives a measure of the overall quality of the observations. Figure 2(b) shows the detail at point P where the four lines intersect at six different points. The cross is at the unique point where the sum of the squares of the residuals is a minimum.</div>
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<b><i>2.2 The mathematical tools</i></b></h3>
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By far the easiest way to handle the enormous amounts of data associated with least squares estimation is to use matrix algebra. In least squares it is necessary to create a system of equations with one equation for each observation and each ‘observation equation’ contains terms for each of the coordinates of each of the unknown points connected by the observation. So, for example, in a two-dimensional network of 10 points where there are a total of 50 observations there would be a set of 50 simultaneous equations in 20 unknowns. Although this represents only a small network, the mathematical problem it presents would be too difficult to solve by simple algebraic or arithmetic methods.</div>

Principle of Least Squares Applied to Surveying

1. Introduction ‘ Least squares ’ is a powerful statistical technique that may be used for ‘ adjusting ’ or estimating the coordinates in...

Free Summer School 2018 in Hansen Summer Institute, U.S.A

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<a href="https://3.bp.blogspot.com/-Dyqul71Vyhk/Wj1ghK4cXwI/AAAAAAAAHYo/PljvEqYgaqg1S3cLvvGzvz9Oqck8t9CfwCLcBGAs/s1600/hansen-summer-institute-2018.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: justify;"><span style="font-family: inherit;"><img alt="Visit U.S.A in Summer: 2018 Hansen Summer Institute on Leadership and International Cooperation for International Students" border="0" data-original-height="333" data-original-width="431" height="308" src="https://3.bp.blogspot.com/-Dyqul71Vyhk/Wj1ghK4cXwI/AAAAAAAAHYo/PljvEqYgaqg1S3cLvvGzvz9Oqck8t9CfwCLcBGAs/s400/hansen-summer-institute-2018.png" title="Visit U.S.A in Summer: 2018 Hansen Summer Institute on Leadership and International Cooperation for International Students" width="400" /></span></a></div>
<div style="text-align: justify;">
<span style="font-family: inherit;"><span style="box-sizing: border-box; color: #223d5b; font-weight: bold;">The Hansen Summer Institute on Leadership and International Cooperation</span><span style="background-color: white; color: #333333;"> </span><span style="background-color: white; color: #333333;">is an exciting international program funded by a generous grant from the Fred J. Hansen Foundation. Six Hansen Summer Institutes took place in San Diego, California between 2007 and 2015. The Institute provides a unique University-based leadership experience and program in international cooperation. For three weeks, young American men and women joined students from a variety of developing countries and regions of social strife. Between then and now,</span><span style="box-sizing: border-box; color: #333333; font-weight: bold;"> Hansen Alumni</span><span style="background-color: white; color: #333333;"> </span><span style="background-color: white; color: #333333;">have remained in contact via a variety of social networking sites and projects funded by the Hansen Foundation. We are happy to announce the Hansen Summer Institute will host its next group of young leaders in July at the University of</span><span style="background-color: white; color: #333333;"> </span><span style="box-sizing: border-box; color: #333333; font-weight: bold;">San Diego School of Leadership and Education Sciences (SOLES)</span><span style="background-color: white; color: #333333;">.</span></span></div>
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<span style="font-family: inherit;"><span id="ctl00_AdminContent_tabApplication_tabYaleFundsList_ctrlGrantsSearch_ctrlFundDetails_lblDescription" style="background-color: white; box-sizing: border-box;">
<span style="color: #333333;"></span></span></span>
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<div style="text-align: justify;">
<span style="font-family: inherit;"><span id="ctl00_AdminContent_tabApplication_tabYaleFundsList_ctrlGrantsSearch_ctrlFundDetails_lblDescription" style="background-color: white; box-sizing: border-box;"><span style="color: #333333;">A primary goal of the program focuses on creating an international community of young scholars who will use their summer experience as a foundation for creating lasting friendships and acquiring common practical understanding of a more peaceful future. Program elements will involve <span style="box-sizing: border-box; font-weight: bold;">classroom instruction</span> and <span style="box-sizing: border-box; font-weight: bold;">hands-on training</span> in the latest techniques of conflict resolution, mediation, and inter-cultural management. Classroom training will complement local excursions to San Diego historical attractions and cultural events including a fourth of July parade, a Padres baseball game, and a harbor cruise. </span></span></span></div>
<span style="font-family: inherit;"><span id="ctl00_AdminContent_tabApplication_tabYaleFundsList_ctrlGrantsSearch_ctrlFundDetails_lblDescription" style="background-color: white; box-sizing: border-box;"><span style="color: #333333;">
</span><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-mBAGltt00VQ/Wj1hd-X1ufI/AAAAAAAAHY0/tTsVssxPCgIKy0LzyNR7DesTh6BPRSzIwCLcBGAs/s1600/hanson_engineersdaily.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Free Summer School 2018 in Hansen Summer Institute, U.S.A" border="0" data-original-height="1200" data-original-width="1600" height="480" src="https://3.bp.blogspot.com/-mBAGltt00VQ/Wj1hd-X1ufI/AAAAAAAAHY0/tTsVssxPCgIKy0LzyNR7DesTh6BPRSzIwCLcBGAs/s640/hanson_engineersdaily.jpg" title="Free Summer School 2018 in Hansen Summer Institute, U.S.A" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Hanson summer school alumni</span></td></tr>
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</span></span><br />
<div style="text-align: justify;">
<span style="font-family: inherit;"><span id="ctl00_AdminContent_tabApplication_tabYaleFundsList_ctrlGrantsSearch_ctrlFundDetails_lblDescription" style="background-color: white; box-sizing: border-box;"><span style="box-sizing: border-box; color: #333333; font-style: italic;">Hansen Summer Institute training aims to provide participants a "</span><span style="box-sizing: border-box; color: #333333; font-style: italic; font-weight: bold;">leadership toolbox</span><span style="box-sizing: border-box; color: #333333; font-style: italic;">" for resolving conflict and building a better future for their respective countries.</span></span></span><br />
<span style="font-family: inherit;"><span style="background-color: white; box-sizing: border-box;"><span style="box-sizing: border-box; color: #333333; font-style: italic;"><br /></span></span></span></div>
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<span style="font-weight: bold;">Eligibility Requirements:</span><br />
<span style="font-weight: bold;"><br /></span></div>
<ul style="box-sizing: border-box; margin-bottom: 10px; margin-top: 0px;">
<li style="box-sizing: border-box; text-align: justify;"><span style="font-family: inherit;">Upper division undergraduate with 2 years of college/university or graduate student with a professional interest in international relations, diplomacy, international economic development or related studies.  </span></li>
<li style="box-sizing: border-box; text-align: justify;"><span style="font-family: inherit;">Student must be between the ages of 20-25 on July 1, 2018.</span></li>
<li style="box-sizing: border-box; text-align: justify;"><span style="font-family: inherit;">Must have demonstrated leadership potential outside of the classroom in the community, nation or region.</span></li>
<li style="box-sizing: border-box; text-align: justify;"><span style="font-family: inherit;">Have an academic advisor verify the candidate's English proficiency (included in reference from the academic referee). </span></li>
<li style="box-sizing: border-box; text-align: justify;"><span style="font-family: inherit;">Have a valid international passport with US visa if necessary by the time the program begins.</span></li>
<li style="box-sizing: border-box; text-align: justify;"><span style="font-family: inherit;">Preference may be given to those who have never visited the United States.</span></li>
</ul>
<div style="text-align: justify;">
<span style="font-family: inherit;">Application deadline: 09 January, 2018</span></div>
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<a href="https://hansensummerinstitute.communityforce.com/Login.aspx?577436547345666C42476777656844477676497A75774F4F374B484E52486D506F2F6F6E56385963496264713544426B5137703065584236634E534245504241525262714E416B436F4853597430586C4D76596572654D4158584A7A6464594971582F57486C324872697169337451323675414C79514A61593257564E7872736D624878506958537A524145442B73455778676E655550756E31464167696945546C34615767664C6D58553656782B614E734B506651594E6A4C732B4F6D37416D3639336E7945503659633D" target="_blank"><span style="font-family: inherit;">Apply here</span></a></div>

Free Summer School 2018 in Hansen Summer Institute, U.S.A

The Hansen Summer Institute on Leadership and International Cooperation is an exciting international program funded by a generous grant...

Overview: Shotcrete and its Types

<div class="text-justify" style="background-color: white; box-sizing: border-box; margin-bottom: 10px; text-align: justify;">
<span style="font-family: inherit;">The gunite alias shotcrete or sprayed <a href="http://www.engineersdaily.com/2016/04/how-to-protect-concrete-against-weathering.html" target="_blank">concrete</a> is formed by mixing cement and sand, in the ratio of 1:3. It refers to mortar or small-aggregate <a href="http://www.engineersdaily.com/2016/04/quality-requirements-of-pumped-concrete.html" target="_blank">concrete</a> that is employed through a wet or dry process. It is conveyed through a hose and pneumatically projected at high velocity onto a surface under a pressure of about 20 to 30 N/cm<sup>2</sup>.</span></div>
<div class="text-justify" style="background-color: white; box-sizing: border-box; margin-bottom: 10px; text-align: justify;">
<span style="font-family: inherit;">Guniting is mostly recommended for <a href="http://www.engineersdaily.com/2017/11/repair-of-concrete-structures-by-steel-plates-fiber-reinforced-plastics.html" target="_blank">repairing concrete</a> work that has been defective because of substandard work or other reasons. It is applied for delivering a watertight layer. Gunite is sprayed pneumatically onto the surfaces at a high velocity surface under.</span><br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-eieIrfecI8A/Wiq4UCuCnPI/AAAAAAAAHYY/B7rBfA_gHoALa_dDZEcXuLDejmnsfSM_QCLcBGAs/s1600/%2528engineersdaily.com%2529Bauarbeiten_%25C3%25B6stliches_Domumfeld-K%25C3%25B6lner_Dom-Spritzbeton-8306.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Overview: Shotcrete and its types" border="0" data-original-height="776" data-original-width="1200" height="412" src="https://4.bp.blogspot.com/-eieIrfecI8A/Wiq4UCuCnPI/AAAAAAAAHYY/B7rBfA_gHoALa_dDZEcXuLDejmnsfSM_QCLcBGAs/s640/%2528engineersdaily.com%2529Bauarbeiten_%25C3%25B6stliches_Domumfeld-K%25C3%25B6lner_Dom-Spritzbeton-8306.jpg" title="Overview: Shotcrete and its types" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><b>Shotcreting in progress</b></span></td></tr>
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<div class="text-justify" style="background-color: white; box-sizing: border-box; margin-bottom: 10px; text-align: justify;">
<span style="font-family: inherit;">Gunite is very effective for tunnels, underground structures, slope stabilization, structural repairs, and pools. It is normally reinforced with traditional steel rods, steel mesh, or fibers. When the gunite is used it starts a instantaneous method of compression and settling.</span></div>
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<span style="font-family: inherit;">Shotcrete is normally a comprehensive term for both the wet-mix and dry-mix versions. In pool construction, however, shotcrete stands for wet mix and gunite to dry mix. In this respect, these terms are not exchangeable.</span></div>
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<span style="font-family: inherit;">Shotcrete is arranged and consolidated simultaneously, because of the force with the nozzle. It is sprayed into different types of shapes or surfaces along with vertical or overhead areas.</span></div>
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<span style="box-sizing: border-box; font-weight: 700;"><span style="color: #cc0000; font-family: inherit;">Categories of Shotcrete : Dry Shotcrete and Wet Shotcrete</span></span></h2>
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<span style="font-family: inherit;">The shotcrete may be used in dry or wet condition. In dry condition, the components are set in a hopper and driven pneumatically via a hose to the nozzle. The inclusion of water at the nozzle is restricted that is mixed up as soon as the material touches the surface. With dry shotcrete or guniting it is possible to modify the water content that should be provided into the mix immediately. It facilitates superior placement process devoid of the inclusion of accelerators. Dry application is suitable when the process entails repeated stops throughout the process of application.</span></div>
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<div class="text-justify" style="background-color: white; box-sizing: border-box; margin-bottom: 10px; text-align: justify;">
<span style="font-family: inherit;">Prepared <a href="http://www.engineersdaily.com/2014/06/methods-of-concrete-construction.html" target="_blank">concrete</a> or the ready mixed concrete is utilized in wet-mix shotcrete. Application of compressed air is prepared at the nozzle that moves the wet mixture over the receiving surface. Less rebound and less dust with regards to dry application of shotcrete has transformed the wet-mix application as the most common process. The benefit of the wet-mix process is to arrange greater volumes in less time.</span></div>
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<span style="box-sizing: border-box; font-weight: 700;"><span style="color: #cc0000; font-family: inherit;">Benefits of Guniting</span></span></h2>
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<ul style="background-color: white; box-sizing: border-box; margin: 0px 0px 10px 25px; padding: 0px;">
<li class="text-justify" style="box-sizing: border-box; line-height: 1.6em; text-align: justify;"><span style="font-family: inherit;">Setting and compression takes place at the same time.</span></li>
<li class="text-justify" style="box-sizing: border-box; line-height: 1.6em; text-align: justify;"><span style="font-family: inherit;">Shotcrete will follow surfaces better than that of regular <a href="http://www.engineersdaily.com/2014/04/steps-in-construction-of-reinforced-concrete-structures.html" target="_blank">concrete</a>.</span></li>
<li class="text-justify" style="box-sizing: border-box; line-height: 1.6em; text-align: justify;"><span style="font-family: inherit;">Shotcrete is also applied with steel fibers to be utilized as a substitution of welded wire mesh. It allows greater flexural strength, ductility and toughness.</span></li>
<li class="text-justify" style="box-sizing: border-box; line-height: 1.6em; text-align: justify;"><span style="font-family: inherit;">It is inexpensive with reference to conventional <a href="http://www.engineersdaily.com/2014/04/measuring-concrete-work-in-construction.html" target="_blank">concrete</a>.</span></li>
<li class="text-justify" style="box-sizing: border-box; line-height: 1.6em; text-align: justify;"><span style="font-family: inherit;">It offers lowered shrinkage and permeability.</span></li>
</ul>
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<span style="box-sizing: border-box; font-weight: 700;"><span style="color: #cc0000; font-family: inherit;">Use of gunite</span></span></h2>
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<div class="text-justify" style="background-color: white; box-sizing: border-box; margin-bottom: 10px; text-align: justify;">
<span style="font-family: inherit;">Gunites are mostly found in slope stabilization, tunneling, retention walls, water tanks and pools, artificial ponds, ditches and channels as well as structural reinforcement and mining applications.</span></div>

Overview: Shotcrete and its Types

The gunite alias shotcrete or sprayed concrete is formed by mixing cement and sand, in the ratio of 1:3. It refers to mortar or small-aggr...

The €21,000 GoEuro Scholarship Giveaway for 2018!

<blockquote class="tr_bq">
To make travel easier for students studying abroad, GoEuro is offering 10 individual scholarships of €2,000 each.</blockquote>
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<h2 style="text-align: justify;">
<span style="color: #cc0000;">Eligibility</span></h2>
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All students that wish to send an application to win the GoEuro scholarship must note:  - That their university or college needs to be eligible for the scholarship first. Students can check if their university or college has already been approved by reviewing the GoEuro “Eligible Universities and Colleges List” (on the GoEuro website).- If a university or college is not mentioned on our “Eligible Universities and Colleges List”, they can contact college@goeuro.com to register themselves.- Students hoping to do a study abroad program in Europe can apply from these countries: United States, United Kingdom, Spain, Germany, Italy, Czech Republic, Poland, Netherlands, Sweden, and Portugal.-Only study abroad programs in EU countries and/or Schengen Area countries are qualified.</div>
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<a href="https://3.bp.blogspot.com/-E41LNcgNjJ0/WiW0Vih-F4I/AAAAAAAAHX0/LfO7gUO-bH81XS0WXLHZOXdxkaEvW3XBwCLcBGAs/s1600/goeuro.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="800" data-original-width="800" height="320" src="https://3.bp.blogspot.com/-E41LNcgNjJ0/WiW0Vih-F4I/AAAAAAAAHX0/LfO7gUO-bH81XS0WXLHZOXdxkaEvW3XBwCLcBGAs/s320/goeuro.jpg" width="320" /></a></div>
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<span style="color: #cc0000;">Benefits</span></h2>
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50 Best Small Business Ideas for Civil Engineers in 2018

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<b>Are you a civil engineer looking to start a business to earn extra money? If YES, here are 50 best small business ideas for civil engineers in 2018.</b></div>
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The construction industry is singlehandedly responsible for the enhancement of infrastructures worldwide. A country or city’s development can be linked to the role civil engineers play in terms of construction of sky scrapers, shopping malls, office complexes and a host of others.</div>
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If you are a civil engineer and would love to dabble into business, the following are 50 business ideas you can select from.</div>
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<a href="https://2.bp.blogspot.com/-Pvj4KNnxCjQ/WiU7cgWIi0I/AAAAAAAAHXk/t_mL8U_H2Ckdo964iw_lCAZ7F95ECbp8QCLcBGAs/s1600/1business_ideas_%2528www.engineersdaily.com%2529.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img alt="50 Best Small Business Ideas for Civil Engineers in 2018" border="0" data-original-height="1196" data-original-width="1600" height="298" src="https://2.bp.blogspot.com/-Pvj4KNnxCjQ/WiU7cgWIi0I/AAAAAAAAHXk/t_mL8U_H2Ckdo964iw_lCAZ7F95ECbp8QCLcBGAs/s400/1business_ideas_%2528www.engineersdaily.com%2529.jpg" title="50 Best Small Business Ideas for Civil Engineers in 2018" width="400" /></a></div>
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<span style="color: #cc0000;">1. Begin a construction company </span></h3>
For civil engineers, this is one of the most common businesses to begin. You can carry out the registration of your <a href="http://www.engineersdaily.com/2017/11/useful-project-management-applications-for-competent-project-management.html" target="_blank">construction</a> company in order to start. Becoming successful in this business, aside from knowing how to deliver quality work, would require remarkable networking skills with individuals who have the capacity to provide you with remarkable construction projects.</div>
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Starting a construction company if you have the required know-how can be a remarkable business venture.</div>
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<span style="color: #cc0000;">2. Start a cement manufacturing plant</span></h3>
This is another business that a civil engineer can dabble into. Although starting this business may require a bit of capital, selling the cement would not be too difficult especially if your rates are highly competitive. Asides that, you can link up with other civil engineers and sell to them whenever they have projects to carry out.</div>
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The profitability of this business is quite high and you stand the chance of making lots of profit especially in areas where buildings are just beginning to spring up.</div>
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<span style="color: #cc0000;">3. Start manufacturing bricks and blocks</span></h3>
This is another great venture for civil engineers. It does not require that much startup capital, and as long as there are buildings under construction, with the appropriate connection and network, this could be a very thriving business. The construction industry is the major user of blocks so ensure you make connections with these industries to get the best out of your business venture.</div>
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<span style="color: #cc0000;">4. Start Selling Cement </span></h3>
This is another profitable venture for civil engineers. Before going into this business, it is best to look for a location where this business is bound to thrive. The best location for this kind of business is one that is not so far from <a href="http://www.engineersdaily.com/2017/11/useful-project-management-applications-for-competent-project-management.html" target="_blank">construction</a> and development sites or other related areas.</div>
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<span style="color: #cc0000;">5. Start Manufacturing Roofing Materials </span></h3>
This is another great venture a civil engineer can try out. In construction, a building is incomplete without a roof, this means that the profitability of this business is on a very large scale. This business is a bit capital intensive but if you have the capacity, you would be able to make great profit in no time.</div>
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<span style="color: #cc0000;">6. Begin Gathers Rental </span></h3>
This is another great business idea which is certain to generate revenue. Gathers are utilized during plastering, roofing, painting among a host of others in high rise buildings and story buildings.</div>
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If you have the required capital to produce gathers as well as adequate space to safeguard them, then this is a business that you should put into consideration. The running cost of this business is low and profit is huge if you are able to appeal to construction companies that will rent your gathers frequently.</div>
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<span style="color: #cc0000;">7. Begin a Nail Production Business</span></h3>
Nails are a necessity for construction. If you are in search of a business venture that would bring you enough funds, then a great business to begin is nail production. Your knowledge as a civil engineer would help you know the kind of nails in demand and which to keep in stock. The market for nails is quite large and if you have a great marketing strategy, you can break into the market easily.</div>
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<span style="color: #cc0000;">8. Provide bricklaying services</span></h3>
As a civil engineer, another great way of making cash is to provide bricklaying services. You can top off your skills by going for adequate training. If you have the capital, you can hire additional hands while you look for the contracts and supervise the work being carried out.</div>
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<span style="color: #cc0000;">9. Embark on the Supply of Sand and Gravel</span></h3>
Another business which is highly profitable that civil engineers can begin is the supply of sharp sand and gravel. There is hardly any job that has to do with building in which these two items are not required. Your skills as a civil engineer can provide you with the basic knowledge of selecting sand of great quality. Additionally, all you would require to begin this business is a truck, tipper and the needed permits.</div>
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<span style="color: #cc0000;">10. Begin a construction cleaning business</span></h3>
Another great business which is highly profitable that can be carried out by a civil engineer has to do with the cleaning of sites before and after <a href="http://www.engineersdaily.com/2017/11/setting-out-construction-works-with-satellite-positioning.html" target="_blank">construction</a>. Most construction companies always carry out cleaning on any construction site before they begin. This is also done after construction as well. This business is highly profitable as new constructions keep going on every time.</div>
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<span style="color: #cc0000;">11. Start a tiles and marbles manufacturing business</span></h3>
This is another great business venture as most houses being built of recent always make use of tiles and marbles for flooring. This means the market for this business is very large and even though it is quite capital intensive, you can be sure of making profit in a short while if you have the ability to market your products. The great thing about this business is that it can be done in an international level.</div>
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<span style="color: #cc0000;">12. Start fixing interlocking slabs and Tiles</span></h3>
This is another available small business opportunity. It has to do with the fixing of marbles, paving stones and tiles. It is a great way to make some cash as a civil engineer, and just a little amount of training is required.</div>
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It is ideal to have the proper network so as to thrive in this business and make profit in little or no time.</div>
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<span style="color: #cc0000;">13. Begin the sale of Tractors</span></h3>
Tractors are crucial in the development of buildings. It is a major equipment used for construction so the market base for them is quite large. Although you may not have the needed funds to compete with the main producers of these machines, you can make plans with a tractor manufacturer you desire so they can give you the opportunity to become a merchant for their products.</div>
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<span style="color: #cc0000;">14. Begin a business of fixing POP </span></h3>
This is yet another means to make funds as a civil engineer. POPs are placed on buildings to make them beautiful. If you want to begin this business, all you require is a little training on the appropriate ways to fix POP. Once that is done, you can begin by making the appropriate connections that would ensure you make as much profit as possible from constant construction businesses.</div>
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<span style="color: #cc0000;">15. Begin a building wiring business</span></h3>
Without the appropriate electrical wiring, a building is not complete. If you are a civil engineer that has learnt about buildings, you can add this to your portfolio and learn how to set up the wiring in buildings. If you are very efficient, this is a very profitable business especially if you have the appropriate network.</div>
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<span style="color: #cc0000;">16. Start producing gates and doors</span></h3>
This is another great business a civil engineer can thrive in. It has to do with the manufacturing of gates and doors. A building is not finished without these two items. You can also become specialized and start manufacturing security doors. The market for these kinds of doors is large and it is a very profitable business.</div>
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<span style="color: #cc0000;">17. Begin a business of Burglary Fixing </span></h3>
Although this business is usually meant for welders, if you have the appropriate capital to invest, you can get a professional welder to come work for you. You also have a choice of undergoing the required training. To thrive in this business, ensure you have the appropriate network so as to get constant business and revenue.</div>
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<span style="color: #cc0000;">18. Start selling construction equipment</span></h3>
As a civil engineer, you can begin the sale of construction equipment. Some of these equipment like pans, shovels and mixers can easily be gotten in any construction shop. All you require to begin this business is the appropriate funding to stock up your shop with construction materials for sale.</div>
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<span style="color: #cc0000;">19. Start a Borehole Drilling Business</span></h3>
In most areas of the world, construction companies always look for their own source of water during a project. At times they may hire the services of a tanker driver to aid them in the delivery of water. If the local government gives you the authority to do so, you can drill your own borehole yourself. So if you have an interest in starting this business as a civil engineer in countries like Nigeria where you can drill boreholes as you desire, you can go into the business and enjoy lots of profit.</div>
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<span style="color: #cc0000;">20. Provide land survey services</span></h3>
This is another profitable business venture to dabble into. Before a building is constructed, there has to be a survey of the land and because of this, the market for land survey services is large. Before going into this business, ensure you have the appropriate network and decide your target market. If you do great jobs, you are bound to get recommendations from your clients.</div>
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<span style="color: #cc0000;">21. Begin a Logging Business</span></h3>
This is another great business for civil engineers who want to go into entrepreneurship. The logging industry is a very massive one in most countries. They are recognized to be the main individuals when it has to do with home <a href="http://www.engineersdaily.com/2017/10/magazine-modern-steel-construction-november-2017.html" target="_blank">construction</a>. Most homes in Canada and U.S.A were constructed using logs, hence selling logs is a great idea.</div>
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Beginning a logging business may require a bit of capital but it is a profitable venture. It requires much capital because of the amount of funds needed to buy equipment for logging and getting the required permits and licences. Nonetheless, it is still a great business to venture into.</div>
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<span style="color: #cc0000;">22. Lawn Care Services</span></h3>
This is another good business for an entrepreneur especially those that love construction related businesses. Interestingly, this is one of the few businesses an entrepreneur can make it big without necessarily working so hard. Major requirements for a successful career here is high level of creativity as well as willingness to go the extra mile. You must be willing to convince clients that you are capable and able to deliver great jobs.</div>
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<span style="color: #cc0000;">23. Wall Paper Fixing</span></h3>
This is of course another construction related business for civil engineers. With wallpapers that are produced in 3D format, apartments are made more beautiful and highly presentable. This business remains one of the simple, easy to go into and lucrative business in the construction related businesses. Successful business people in this line are good marketers of their services, and they have strong networking skills.</div>
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<span style="color: #cc0000;">24. Plumbing Business</span></h3>
It is a well known fact that a house is not complete without full plumbing services. There is a scarcity of plumbing experts in communities in recent times. It is important to note that you can make lots of money here. You can work alone or with few employees in this business.</div>
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<span style="color: #cc0000;">25. Landscaping Services</span></h3>
Landscaping is another business opportunity that offers great financial reward. This business entails environment beautification. Landscape architecture entails a number of processes that include the planning, <a href="http://www.engineersdaily.com/2014/04/steps-in-design-process.html" target="_blank">designing</a>, management, preservation as well as rehabilitation of the land and landed properties. In this business, you will need to work very hard before financial rewards can result. The civil engineer must learn to be skilled in negotiation and be able to convince prospective clients that he or she can deliver quality work.</div>
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<span style="color: #cc0000;">26. Haulage Services</span></h3>
Haulage business is another making money venture within the construction industry for civil engineers. In the real sense of it, haulage business handles the movement of materials needed on construction sites such as gravel, cement, blocks, rods, sand, construction equipment as well as other stuffs. This shows that haulage business is a cool way of making money in the construction industry. Target these materials sellers and building contractors and make your money from them.</div>
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<span style="color: #cc0000;">27. Construction Equipment Rental Business</span></h3>
Construction equipment rental business is a great business venture for civil engineers. Any serious civil engineer willing to start a business may consider this a lucrative option.</div>
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Construction equipment include tractors, concrete mixers, cranes, gathers etc and they are always needed on construction sites. This business is relatively capital intensive as those construction equipment cost a fortune especially the likes of cranes and tractors. Endeavor to network with stakeholders in the construction industry and ensure your office location is strategic enough to attract customers.</div>
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<span style="color: #cc0000;">28. Property Development Business</span></h3>
This is a wonderful construction related business with lots of profit opportunities. By division, it is categorized as a construction business and it has the capacity to enrich serious entrepreneurs within a short time. This business encompasses all activities that include land purchase, rent or lease and selling, leasing or renting out of furnished properties.<br />
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In essence, it is the duty of developers to turn ideas into real properties. This means that developers acquire land, finance real estate deals and then conclude the building projects. After this, they offer the property for sale, lease, rent as well as manage properties on client’s behalf.</div>
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<span style="color: #cc0000;">29. Safety Gadgets Production</span></h3>
Of course safety gadgets are construction related materials needed during construction. They include Safety Helmets, C – Caution, Safety Boots and other safety materials.<br />
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This is another business that a civil engineer can go into. Since work cannot be done except these gadgets are worn, it means that the market is large. Safety gadgets like helmets, safety boots, protective goggles, overalls, safety vest (bib) etc. are important and needed in large quantities. So if you are thinking of starting this business, note that you are required to work with the standard and specifications issued by the regulatory bodies within the industry.</div>
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<span style="color: #cc0000;">30. Interior Decoration Services</span></h3>
This is a construction related business as well as a home improvement service. Interior decoration entails the making of offices and homes more beautiful, as well as giving buildings a facelift. Activities may include things like apartment color selection, lighting selection, blind selection and several other activities required to show forth the beauty of a house. This is a very lucrative business that is demanded every now and then.</div>
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<span style="color: #cc0000;">31. Aluminum Products Manufacturing</span></h3>
Lots of products can be produced from aluminium and some of these products include windows, roofs, doors, pans etc. If you seek a construction related business to go into, you may consider venturing into the production of aluminium products.<br />
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This is thriving and lucrative business. Before you begin this business, endeavour to carry out a thorough business research so as to spot the sellable aluminium products and to build a workable marketing concept for the product.</div>
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<span style="color: #cc0000;">32. Furniture Polishing Business</span></h3>
Furniture polishing services is another leading business that a serious civil engineer who is ready to make money should consider. There are thousands of people who are willing and ready to pay for this service out there. Furniture like cupboard, cabins, wardrobe, tables, shelves as well as any wooden product can come back to live and shine out its beauty if well polished.</div>
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<span style="color: #cc0000;">33. Water Closet and Ceramic Wares Production</span></h3>
Washing hand basins as well as water closets remain part of essentials in any building. A building without a toilet is regarded as not complete. This stresses the high demand for water closets and other ceramic wares. So you may consider starting a manufacturing company for these products.</div>
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<span style="color: #cc0000;">34. Home Painting Business</span></h3>
Home painting is another highly profitable business within the sphere of construction related businesses. Any serious civil engineer with the appropriate training can make lots of money from this area. Home painting is a way to beautify the house after construction. This shows that great money making opportunities abound in this business venture.</div>
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<span style="color: #cc0000;">35. Floor Cleaning Services</span></h3>
Floors irrespective of the type such as tiles, terrazzo, marbles, wooden floors etc all require cleaning and stain removal services. This is another thriving and lucrative business that any focused civil engineer who wants to make money from construction related businesses can consider.<br />
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Although this business also falls under the cleaning industry, it is best to note that professionalism in general cleaning services is required. To make it real big here, please go through training before setting out or simply learn from a successful person in the business.</div>
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<span style="color: #cc0000;">36. Overhead and Underground Tanks Supply Business </span></h3>
This is another profitable business venture in that any ambitious civil engineer can delve into and make lots of money.<br />
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Both overhead and underground tanks are used for water storage in buildings as well as on construction sites. It is difficult to find a building without at least one overhead tank or an underground tank. This business doesn’t require technical skills to initiate and run. Your startup capital and registration are all you need for the business. You also need to build good business relationships with stakeholders in the construction industry.</div>
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<span style="color: #cc0000;">37. Iron rods Supply </span></h3>
Iron rods are part of the major building materials that are used in construction. Iron rods are primarily used for re-enforcement, railings, as well as for burglary proofs. This therefore shows its large market demand in the construction industry.<br />
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Both technical knowledge and experience are not required before you can go into this business. Startup capital and business registration are the major things you need to kick start the business while networking with stakeholders in construction sites is needed to grow the business.</div>
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<span style="color: #cc0000;">38. Setting up Air conditioners</span></h3>
This business is highly lucrative amidst businesses in the construction value chain. Any aspiring entrepreneur can successfully begin the installation of electric water heaters and air conditions in buildings. There is a great demand for this business most especially if you are a good salesperson. Endeavour to work and network with site supervisors and other stakeholders in the industry. They are your best business leverage.</div>
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<span style="color: #cc0000;">39. Ceiling Production</span></h3>
Recently, people now make use of POP, but the sale of other ceiling materials is not affected by the advent of POP. Ceiling materials such as asbestos, wood as well as other ceiling materials are still in use in the construction industry. This is a great business opportunity for civil engineers. The only challenge is pushing your products into the market.</div>
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<span style="color: #cc0000;">40. Bitumen and Tar Supply </span></h3>
Road construction and maintenance are some of the key components of civil engineering. Two major raw materials used when constructing roads are tar and bitumen. This shows that there is a great demand for tar and bitumen. One of the businesses that is profitable and thriving is the supply of tar and bitumen. You can network your business with the ministry of works or public works department (PWD) in your country and make valuable profit.</div>
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<span style="color: #cc0000;">41. Construction Consultant </span></h3>
Normally before any construction contract is awarded to contractors, a construction consultant is usually called upon to look into the entire project.<br />
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Construction consultants look into the construction plans and other related matters and then offer advice to individuals, government and corporate organizations so as to be properly guided before going into the construction job proper.<br />
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If you possess the appropriate qualifications as well as lots of experience in the construction industry as a civil engineer, starting a construction consulting business is not a bad idea. If you deliver quality insight, you are sure to get long term contracts with both corporate bodies and the government of your country.</div>
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<span style="color: #cc0000;">42. Maintenance of Roofs</span></h3>
Roof maintenance and restoration is a lucrative and thriving business in the construction industry. Every civil engineer can initiate this business with moderate training.<br />
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Generally, roofs wear and tear as a result of exposure to hash climatic conditions. This is why roofs leak within a period of time. Roof maintenance and restoration companies do fix leakages in roofs and as well replace worn out roofs with new ones. This business can be classified into post construction maintenance business and is highly lucrative.</div>
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<span style="color: #cc0000;">43. Part-Time Lessons on Civil Engineering</span></h3>
Civil engineers can teach part-time lessons to aspiring civil engineers. The customer base includes students in universities and other civil engineers who desire to learn more in their field. This is a great idea for a civil engineer with great skill in the field.</div>
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<span style="color: #cc0000;">44. Blogging </span></h3>
This is another well-known business venture world-wide. A civil engineer can startup a blog and write on articles that are related to civil engineering. With time and consistency, the appropriate crowd would be directed to the site and money can be made off adverts especially if your blog is known to be a reliable one.</div>
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<span style="color: #cc0000;">45. E-book writer </span></h3>
As a civil engineer who is well versed in his/her field, you can begin writing eBooks to make profit. You do not have to be an exceptional writer as what is required is your idea. You can get the assistance of an editor to help you in making your eBook more professional. If you have great insights, you are going to attract clients and make money off the sales of your eBook.</div>
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<span style="color: #cc0000;">46. Freelance Civil engineer</span></h3>
This is another great business venture for civil engineers. You can offer your services on a freelance basis and get clients from anywhere. If you always do great jobs, your clients would spread the word and with time your customer base would increase tremendously. This is a great business if you really know what you are doing.</div>
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<span style="color: #cc0000;">47. Construction of roads</span></h3>
As a civil engineer, you can network with the government and get contracts to construct roads. This is a great source of income if you know the right people to link up with. Additionally, if your work is great, you stand the chance of making lots of cash and getting future government contracts.</div>
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<span style="color: #cc0000;">48. Offer childproof services </span></h3>
This is another business which has a high demand. You can offer to make homes child proof for parents by installing equipment round the home that would keep children safe.</div>
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<span style="color: #cc0000;">49. Chimney repairs</span></h3>
A lot of homes and companies still make use of chimneys. They are prone to damages and a good business venture is offering repair services for these chimneys. There is a lot of money to be made as a civil engineer if you go into cleaning and repair of chimneys.</div>
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<span style="color: #cc0000;">50. Construction estimation service</span></h3>
As a civil engineer with the appropriate experience, this can be a great business venture. You render services by offering companies or individuals who want to build homes estimation services. You are called in as an expert to assist them in determining the possible amount they would spend so as to prevent them from spending excessive amount of cash. This is a great business if you are great at what you do. </div>

50 Best Small Business Ideas for Civil Engineers in 2018

Are you a civil engineer looking to start a business to earn extra money? If YES, here are 50 best small business ideas for civil engineers...

Types of Earth Retaining Structures or Excavation Supports and their Applications

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Excavation support or earth retaining structures are required where <a href="http://www.engineersdaily.com/2011/04/types-of-excavation.html" target="_blank">excavation</a> is deep and required slope cannot be provided. Types of excavation supports are discussed.</div>
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<span style="color: #cc0000;">What Are Excavation Supports?</span></h2>
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In general, to construct a structure either above the ground or below the ground, excavation of <a href="http://www.engineersdaily.com/2014/03/properties-of-soil.html" target="_blank">soil</a> is necessary in the ground.</div>
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The excavation may be shallow or deep based on our requirement. But when deep cuts are made in soil, the soil from the sides of excavated area may collapse due to low stability.</div>
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To prevent this and to make the cut accurate vertical we need some temporary earth <a href="http://www.engineersdaily.com/2014/01/principles-of-geotechnical-engineering.html" target="_blank">retaining structures</a> called excavation supports.</div>
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<div style="text-align: justify;">
The failure of soil cut arises when the limit of excavation exceeds its safe height limit and it depends upon unconfined compressive strength of soil and cohesion.</div>
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<div style="-webkit-text-stroke-width: 0px; color: black; font-family: "Times New Roman"; font-size: medium; font-style: normal; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: justify; text-decoration-color: initial; text-decoration-style: initial; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;">
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="-webkit-text-stroke-width: 0px; font-family: "Times New Roman"; letter-spacing: normal; margin-bottom: 0.5em; margin-left: auto; margin-right: auto; orphans: 2; padding: 6px; text-align: center; text-decoration-color: initial; text-decoration-style: initial; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px;"><tbody>
<tr><td style="text-align: center;"><div style="margin: 0px;">
<a href="https://2.bp.blogspot.com/-qJYiwnvl0Lk/WiFSZqAO0rI/AAAAAAAAHVo/zE3RksqkYFUKmarxYxTNrYjJBNnk3KvPQCLcBGAs/s1600/engineersdaily_excavation-support.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img alt="Types of Earth Retaining Structures and their Applications" border="0" data-original-height="379" data-original-width="502" height="301" src="https://2.bp.blogspot.com/-qJYiwnvl0Lk/WiFSZqAO0rI/AAAAAAAAHVo/zE3RksqkYFUKmarxYxTNrYjJBNnk3KvPQCLcBGAs/s400/engineersdaily_excavation-support.jpg" title="Types of Earth Retaining Structures and their Applications" width="400" /></a></div>
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<tr><td class="tr-caption" style="font-size: 12.8px; padding-top: 4px; text-align: center;"><div style="margin: 0px;">
<span style="font-size: small;"><b>Bracing of an excavation</b></span></div>
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</tbody></table>
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Following table provides the safe height limit for different soil types based on their unconfined compressive strength and cohesion limits.<br />
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<center>
<table style="border-collapse: collapse; border-spacing: 0px; text-align: center;"><tbody>
<tr><th style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; font-weight: bold; overflow: hidden; padding: 10px 5px; word-break: normal;">Soil type</th><th style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; font-weight: bold; overflow: hidden; padding: 10px 5px; word-break: normal;">Unconfined compressive strength (psf)</th><th style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; font-weight: bold; overflow: hidden; padding: 10px 5px; word-break: normal;">Cohesion(psf)</th><th style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; font-weight: bold; overflow: hidden; padding: 10px 5px; word-break: normal;">Safe height (ft)</th></tr>
<tr><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">Very soft</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">Less than 500</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;"><250</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;"><5</td></tr>
<tr><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">Soft</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">500-1000</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">250-500</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">5-10</td></tr>
<tr><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">Medium</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">1000-2000</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">500-1000</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">10-20</td></tr>
<tr><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">Stiff</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">2000-4000</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">1000-2000</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">20-40</td></tr>
<tr><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">Very stiff</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">4000-8000</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">2000-4000</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">40-80</td></tr>
<tr><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">Hard</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">>8000</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">>4000</td><td style="border-style: solid; border-width: 1px; font-family: "arial" , sans-serif; font-size: 14px; overflow: hidden; padding: 10px 5px; word-break: normal;">>80</td></tr>
</tbody></table>
</center>
<h2>
<span style="color: #cc0000;"><br />Types of Excavation Supports</span></h2>
<div>
<span style="color: #cc0000;"><br /></span></div>
<div>
Generally, there are two most commonly adopted methods of providing excavation supports:</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
(i) Soldier pile and lagging</div>
<div style="text-align: justify;">
(ii) Soil nailing</div>
<div style="text-align: justify;">
<br /></div>
<h3>
<span style="color: #cc0000;">Soldier Pile and Lagging</span></h3>
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<div>
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<div>
Soldier piles are nothing but I-sections which consists web between two flanges. These I-sections are drilled into the ground around the periphery of an excavation. The piles are driven to the point slightly below the required excavation depth.</div>
<div style="text-align: justify;">
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-qoYp5juDn78/WiFXtQcPCTI/AAAAAAAAHV4/o1x9f-nP2GAKGjnD6gHiugOE9_6v7-KXgCLcBGAs/s1600/%2528engineersdaily.com%2529soldier-pile-lagging.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img alt="Soldier pile & lagging" border="0" data-original-height="288" data-original-width="300" src="https://4.bp.blogspot.com/-qoYp5juDn78/WiFXtQcPCTI/AAAAAAAAHV4/o1x9f-nP2GAKGjnD6gHiugOE9_6v7-KXgCLcBGAs/s1600/%2528engineersdaily.com%2529soldier-pile-lagging.jpg" title="Soldier pile & lagging" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><b>Soldier pile & lagging</b></span></td></tr>
</tbody></table>
<br /></div>
<div style="text-align: justify;">
Weak concrete is used for grouting of piles. The spacing between every two adjacent piles is limited to 10 feet. After that exaction is done and the surrounded soil is well supported by the flanges of piles.</div>
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<br /></div>
<div style="text-align: justify;">
In between the piles, wood lagging is used. The lagging consists long timber sheets or planks placed behind the front flanges of piles to support the soil between the piles.</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
The timber is of 2 to 4 inches thickness, so, some manual excavation behind the front flange is needed. To offer strong bond between horizontal wood sheets and front flange, welded studs, clips etc. are used.</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
For narrow cuts which have limited width and more depth, excavation bracings are provided in the form of struts. Struts are connecting member which connect the one side cut wall to another cut wall horizontally.</div>
<div style="text-align: justify;">
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-dH0Nf8AeHyA/WiFXyQE0b-I/AAAAAAAAHV8/mCe1KmyZihIpGeYQLHbpIk9TlqS0Ugy_gCLcBGAs/s1600/%2528engineersdaily.com%2529excavation-support-structure-soldier-pile-lagging.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Soldier pile & lagging" border="0" data-original-height="346" data-original-width="681" height="323" src="https://3.bp.blogspot.com/-dH0Nf8AeHyA/WiFXyQE0b-I/AAAAAAAAHV8/mCe1KmyZihIpGeYQLHbpIk9TlqS0Ugy_gCLcBGAs/s640/%2528engineersdaily.com%2529excavation-support-structure-soldier-pile-lagging.jpg" title="Soldier pile & lagging" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><b><span style="font-size: small;">Soldier pile & lagging</span></b></td></tr>
</tbody></table>
</div>
<div style="text-align: justify;">
To install struts, horizontal member called waler is arranged in front of wooden lagging. If the excavation is very wide, then inclined struts called rakers are used.</div>
<div style="text-align: justify;">
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-1slZhB0XOGE/WiFYX2CgSnI/AAAAAAAAHWE/eu8I-d-7Qk8g8xtufdLerbkgyULY79DRgCLcBGAs/s1600/%2528engineersdaily.com%2529earth-retaining-structure-soldier-pile-lagging.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Soldier piles & lagging for wide excavation with horizontal struts" border="0" data-original-height="379" data-original-width="431" height="562" src="https://2.bp.blogspot.com/-1slZhB0XOGE/WiFYX2CgSnI/AAAAAAAAHWE/eu8I-d-7Qk8g8xtufdLerbkgyULY79DRgCLcBGAs/s640/%2528engineersdaily.com%2529earth-retaining-structure-soldier-pile-lagging.jpg" title="Soldier piles & lagging for wide excavation with horizontal struts" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><b>Soldier piles & lagging for wide excavation with horizontal struts</b></span></td></tr>
</tbody></table>
<br /></div>
<h3>
<span style="color: #cc0000;">Soil Nailing Method of Excavation Support</span></h3>
</div>
<div>
<br />
<div>
Soil nailing is another technique of protecting excavated ground. It is economical and rapid process. In this case, soil is reinforced in situ to make it stable.</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-XKFTtlGEHZU/WiFYvezMeHI/AAAAAAAAHWI/wkAn9b8XRk40Qze6to86HMetzNmqw6EaQCLcBGAs/s1600/%2528engineersdaily.com%2529soil-nailing-method.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img alt="Soil nailing method of earth retention" border="0" data-original-height="373" data-original-width="638" height="233" src="https://2.bp.blogspot.com/-XKFTtlGEHZU/WiFYvezMeHI/AAAAAAAAHWI/wkAn9b8XRk40Qze6to86HMetzNmqw6EaQCLcBGAs/s400/%2528engineersdaily.com%2529soil-nailing-method.jpg" title="Soil nailing method of earth retention" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><b>Soil nailing method of earth retention</b></span></td></tr>
</tbody></table>
For soil nailing, firstly shallow cut is excavated and then the cut is coated with shotcrete. Shotcrete is nothing but concrete which is sprayed through pipes with some force. On the shotcrete area, soil nails are driller and grouted.</div>
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<div style="text-align: justify;">
The Group of nails installed on a grid holds the soil in a stable manner. The same process is repeated until the required depth is reached.</div>
<div style="text-align: justify;">
<br /></div>
<div style="text-align: justify;">
Soil nailing is more effective and easier if it is done with subsequent layers of installation. Even though it is rapid in <a href="http://www.engineersdaily.com/2011/01/causes-of-disputes-in-construction.html" target="_blank">construction</a> it needs skilled persons to who are having knowledge on geo technology and craftsmanship. Soil nailing should be more effective above the <a href="http://www.engineersdaily.com/2017/11/groundwater-control-in-excavations-at-construction-sites.html" target="_blank">ground water</a> table level.</div>
<div style="text-align: justify;">
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<div style="text-align: justify;">
Soil nailing is mostly used for rail or road embankments, tunnel excavations, retaining structures for high rise buildings etc. Soil nailing structures provides good resistance against seismic activities and deflections are also with in the tolerable limits.</div>
<div style="text-align: justify;">
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-sL3CJTD8fq8/WiFY7gl2a4I/AAAAAAAAHWQ/ByouUavYI40b_hyfnXZ7EaTLlKD60LDkgCLcBGAs/s1600/%2528engineersdaily.com%2529soil-nailing-excavation-support.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img alt="Schematic diagram for soil nailing method of earth retention" border="0" data-original-height="379" data-original-width="452" height="268" src="https://4.bp.blogspot.com/-sL3CJTD8fq8/WiFY7gl2a4I/AAAAAAAAHWQ/ByouUavYI40b_hyfnXZ7EaTLlKD60LDkgCLcBGAs/s320/%2528engineersdaily.com%2529soil-nailing-excavation-support.jpg" title="Schematic diagram for soil nailing method of earth retention" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;"><b>Schematic diagram for soil nailing method of earth retention</b></span></td></tr>
</tbody></table>
<br /></div>
<div style="text-align: justify;">
Sometimes this excavation bracings or rakers may disturbs the field operations. To overcome this, tie back system is developed. In this case, tie back bars or anchor bars are installed in the soil cut that is behind the excavation support.</div>
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<br /></div>
<div style="text-align: justify;">
So, these tie backs holds the excavation supports and they are grouted to the rock below the ground. From this lateral earth pressure also prevented and the load from the <a href="http://www.engineersdaily.com/2014/02/book-elements-of-theory-of-structures-jacquesheyman.html" target="_blank">structure</a> is carried to rocks through this tie backs.</div>
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<br /></div>
<div style="text-align: justify;">
The angle of inclination of anchors is decided based on the soil behavior and availability of hard stratum but In General 10 to 20-degree inclination is provided for anchors.</div>
</div>

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