Bay Area Seismic Earthquake Retrofit House Home Bolting

Описание: The retrofitting principles discussed here only deal with the area under the floor. This is because most commonly observed earthquake damage is caused by inadequate lateral bracing under the floor. Under the house, there are generally almost no effective earthquake resisting elements such as bolts and plywood. The most critical part of the plywood shear wall construction is the attachment to the bolted mudsill.

Above the floor, interior finishes on the walls and partitions, though not designed to resist earthquakes, do in fact provide a lot of earthquake resistance and typically brace the house against serious damage. After a quake, wall and partition finishes may be cracked, doors and windows may be racked, and costly repairs may be required to restore livability to common standards, but damage above the floor is much less likely to result in a hazardous condition than would be found in a house damaged due to inadequate underfloor bracing. Effective underfloor bracing should keep your house from falling from its foundation. You should not expect that an underfloor retrofit will protect your house from earthquake damage above the floor.

Most homes need to be strengthened in three areas:

1. The cripple walls need to be braced with plywood.
2. The braced cripple walls need to be bolted to the foundation.
3. The floor of the house needs to be attached to the braced cripple walls.

All three of these components form a shear wall. If the shear wall is tall and narrow, you will also need hold downs to resist overturning.    • How to Seismic Retrofit a House - Shear Wa...  


The plywood-braced cripple walls should be bolted to the foundation to keep them from sliding off of the foundation. It is not necessary to put plywood on the entire cripple wall. Knowing how much plywood and how many bolts to install involves the use of an engineering formula known as the base shear formula.    • Видео  

When evaluating bids from other companies like quakebusters and earthquake safety, you will find this information indispensable.