3. Determine the safety of other buildings you use

Unreinforced brick buildings pose a particular hazard even in moderate earthquakes.Unbraced parapets and walls inadequately tied to the floors and roof can topple onto sidewalks or adjacent buildings. Many such buildings are currently used for low-income housing and commercial space in the Bay Area. The Unreinforced Masonry Building Law required all local governments to conduct an inventory of existing unreinforced masonry buildings and to develop a mitigation plan by January 1990. If you are concerned about these buildings, contact your local building department to see what is being done with this inventory.

Many masonry buildings can be made more resistant to earthquakes by adding an internal frame, such as the one shown here, and bolting the walls to the frame.

Concrete-frame structures built before 1976 will likely pose a hazard, even during moderate earthquakes. This design was commonly used for mid-rise office and commercial buildings in our cities. These structures are readily damaged by repeated earthquake shaking and can collapse catastrophically. The collapse of a single mid-rise structure of this type in a California earthquake could result in more deaths than the total loss of life during all earthquakes in California since 1906.

This diagonal steel frame effectively braces a concrete frame building housing U.S.Geological Survey Employees.

"Tilt-up" buildings built before the local adoption of the stricter 1976 Uniform Building Code are another type of concrete structure that has proven particularly vulnerable to damage during moderate or larger earthquakes. These buildings have concrete walls precast on the ground and then tilted vertically into place. They often fail at the connections between the walls, the floor, and the roof. Strengthening the connections is a relatively inexpensive procedure. These buildings house many of the major industrial activities of the Bay Area; their collapse could cause severe economic loss and release of hazardous materials.

Getting Your Building Inspected

How do you locate a professional to advise you on the resistance of your building to earthquake shaking? Civil and structural engineers and architects are trained and licensed to provide such information about structures. Geologists, foundation engineers, and geotechnical engineers are trained and licensed to evaluate the soil conditions and recommend appropriate action. When hiring such a consultant, you are asking an experienced professional to review a potential problem and possibly to provide plans and specifications for correcting the problem. The amount of work required is not known when you hire the consultant, and thus it is important to select someone you trust and to develop a scope of work as you proceed. A good place to start is to call a professional organization and ask for information about the different types of work that might be required, for information about how to select an engineer, geologist, or architect, and for a list of members in your area. Contact several firms or individuals to determine if they do the different types of work you need. Ask for information that explains the type of firms they are and that identifies others whom they have served. Check to see how satisfied other clients were. Recognize that the quality of the advice given and of the work performed, as well as the price you pay, may depend critically on the care you take in making a selection. Become informed. Even if you do not understand the technical details, ask enough questions to understand the concepts and relative importance of the issues involved. Do not be afraid to ask questions that you fear might appear stupid. Your money is going to be spent, so you have a right to understand what needs to be done and why. For projects more complex than inspecting a single-family home, you should meet with the selected firm and discuss the options. In almost every case, there will be a number of approaches for solving any given problem. Get the consultant to explain the pros and cons of each, as well as the dollars and risks involved. Once this is done, you will have defined the work the consultant will do for you. Then a fee can be set and you can discuss how changing the work would change the fee. State and federal agencies do not inspect individual buildings. Your local building department may be willing to inspect your building, but they are not authorized to recommend actions to be taken.