Retrofitting Foundation Anchors

The primary purpose of earthquake retrofitting is to keep your home from being displaced from its concrete foundation. Existing homes need to be retrofitted because our understanding of the effects of earthquakes as well as construction techniques have improved after the homes were built.

The Problem:

During a earthquake a house moves from side to side and up and down, causing the house to move off its foundation if it is not anchored. This can cause damage to floors, walls, windows and possible fire from a broken gas line and other utilities connected to the house.

How it identify it:

A home built off the ground has a crawl space between the ground and floorboards. Look for Anchors fastening the sill plate / wooden boards that sit directly onto of the concrete foundation (Figure 1). You will be able to see washers and nuts installed every 4’ to 6’ along the sill plate. Steel plates are sometimes used instead of a anchor bolt connecting the foundation to the house.

What can be done:

If the house is Not Anchored, Drill holes through the sill plate into the concrete foundation and install anchor bolts, if there is not enough room to successfully drill, you can attach steel plates to attach the sill plate to the foundations (Photo below).

Detailed specifications for different solutions can be found in the Uniform Code for Building Conservation, Appendix Chapter 6.

There are several methods available for Earthquake Retrofit placement from Hilti, Simpsons and RedHead. Contact a General Contractor or Engineer for additional information.

KINGISI can inspect: All Angle Iron Struts, Foundation Bolting, Epoxy, Expansion Anchors, Retrofit Connectors and Brackets. Give us a call today!!!!!!!.