Earthquake creates building-saving role for contractor.

The Northridge Earthquake created new challenges for contractors within our built environment. While usually devoting their expertise to assembling raw materials into the designs envisioned by architects and owners; contractors were trying to stabilize and save structures following the earthquake.

The first weeks after the earthquake have found "hands-on" contractors very busy. Some have their own work crews, equipment and sources of material, but glass, timber shoring and power lifting and loading equipment soon became scarce. As calls came in from new customers and old, a sort of "triage" approach developed.

Life safety situations took priority, a collapsing cupola was shored, atop the stair tower on a senior citizens home in Santa Monica; joints were re-sealed and structural connections shored and strengthened at a bank in Woodland Hills; and broken columns in parking structures were shored in Sherman Oaks. Crews went to work around-the-clock to re-anchor the 85 foot high concrete block firewall which protects Beverly Center from an adjacent oil drilling site. The shopping center was never in danger, but the oil workers could not enter their site until the wall was stabilized. Service interruption is next in the order of concern, and the company soon found itself repairing the 13-story shear walls of a Sherman Oaks office building, devising ways to insert bracing within the towers of UCLA's historic Royce Hall, and shoring floors and columns at The Broadway department store in Northridge. Damage repair work continues at this writing, with work underway at a dozen sites, and the emphasis on restoration of service and permanent repairs.

LONG TERM IMPROVEMENTS: UPGRADES AND RETROFIT

Earthquakes are full-scale, tragic laboratories for the testing of design and construction standards and performance. Information is gained from each major event, and especially from the well-recorded and studied ones in California in 1933, 1940, 1971 and 1989. From that work has come the progress which held our death toll to a very low level, when compared to recent quakes of similar magnitude in Mexico City and Armenia.

Business interruption and economic loss are another story. The extent of loss in this event has surprised many, and is expected to profoundly influence future decisionmaking by public agencies and private individuals and institutions. The measured levels of acceleration in the Northridge quake far exceeded those anticipated and code revisions seem certain. It is possible that such revisions will for the first time set "Levels of Performance," with the lowest level being the current standard which aims to preserve Life Safety. The next level would be Limited Interruption of Use ("Interruptible Power" in utility industry terminology). The highest level would seek to assure Continuity of Operation, similar to the higher standard now assigned to hospitals, fire stations and the like.

Some farsighted owners already are voluntarily building or retrofitting their structures to meet higher standards. Many structures strengthened in recent years have come through this most recent event with no interruption in service. These included mid-rise office buildings of 1960s vintage, at 9595 and 9720 Wilshire Blvd. in Beverly Hills; two seven-story dormitories at UCLA; and the Rockwell Corporate Headquarters in Seal Beach. On-going seismic retrofitting of the historic Powell Library on the UCLA campus performed very well at upgraded areas. More owners are expected to realize the cost effectiveness of such upgrading, as the result of January's event.

In an emergency, preparation counts, and relationships count a lot. Most of the work done during the days immediately following the quake was on the basis of phone calls, faxed instructions and handshakes. Paperwork is just now beginning to catch up. Professional architects and engineers will continue to work through professional associations and public code agencies to bring about further positive change. Let's hope that these changes will make us more prepared for when the forces of nature come calling again.

Terry Dooley is senior vice president of Morley Construction Company, and a member of the Seismic Rehabilitation Advisory Panel of the Building Seismic Safety Council. He is a member of the Earthquake Engineering Research Institute, the Structural Engineers Association of Southern California, and Director-Nominee of the American Concrete Institute.