A safe house must have a strong foundation.
• The ground under the building has to bear the weight of a house. If it is weak soil, the foundations must be made stronger. If the house has more than one floor, the foundation must also be made stronger. Foundations are best when continuous under the house.
• Is the building built on sand, rock, clay?
• Soil for a good foundation that can carry the weight of a house must be well drained so that it is dry and not waterlogged.
• Waterlogged soil can become liquefied in an earthquake - turn to a semi-liquid – so that structures sink into the ground.
• Is the building built on sand, rock, clay?
• Soil for a good foundation that can carry the weight of a house must be well drained so that it is dry and not waterlogged.
• Waterlogged soil can become liquefied in an earthquake - turn to a semi-liquid – so that structures sink into the ground.
Example of bad foundations
The houses are being built in a swampy, flood-prone area. Soon after they were built the houses were flooded when there was heavy rain and water entered the houses. These foundations in permanently wet soil will also be weak when an earthquake shakes the ground.
Liquefaction
Example of a well-built and well-structured house that was not quite finished when a major hazard struck. The house was good but the foundations were poor. Due to a major earthquake the foundations suffered from liquefaction of the ground, and due to the weight of the house, it subsided unevenly into the ground.
