Studies Ordered for Old Masonry Buildings
Calling the risk too great to ignore, the Santa Monica City Council is requiring all owners of pre-1933 unreinforced masonry buildings to conduct seismic engineering studies by next January to determine the structures’ resistance to earthquakes.
The council stopped short of proposing specific corrective measures, saying it was unprepared to do so because of conflicting data about how dangerous the buildings are. The council instead voted at its Tuesday night meeting to gather more expert opinion before determining later this year what constitutes an adequate level of safety.
Officials said the city has 183 unreinforced masonry buildings built before 1933. Four are residential buildings, but most are commercial or mixed-use structures, with the bulk of them in the downtown business district. Under a 1986 state law, the city is required to make an inventory of its old masonry buildings, set up a program for making them safe and report back to the state on their progress by Jan. 1, 1990.
Although cities have some latitude in how they comply with the law, the state recommends that all unreinforced masonry buildings constructed before 1933 be divided into risk groups depending on their use and occupancy. Load-bearing walls should then be reinforced, with priority given to the buildings found most dangerous. The state program is modeled after one instituted by the city of Los Angeles in 1980.
Santa Monica’s Building and Safety Commission held two public hearings last winter on implementing the state law but concluded that additional studies would be necessary to determine the safety of the buildings and what corrections were needed.
Testimony by experts and members of the public Tuesday and at last winter’s sessions showed clear differences of opinion about the ability of pre-1933 masonry buildings to withstand earthquakes.
Points of dispute focus on determining buildings’ resistance to ground forces generated by earthquakes, the actual potential for a damaging quake and the cost of upgrading buildings.
The council authorized the city staff to determine the best scientific standards for assessing the risk of earthquake damage in the buildings and to reconcile contradictory or competing claims of hazard. The staff will also determine cost estimates based on Los Angeles’ figures from its 1980 ordinance.
“There seems to be some misinformation in the community, as well as honest disagreement” about how dangerous the buildings are, said Mayor Dennis Zane. “It would be irresponsible of us if we did not impose this moderate (step) of implementing these tests.”
Aside from Los Angeles, several other major cities in the area have already conducted inventories and adopted a version of the state’s suggested mitigation program. They include Long Beach, Torrance, Pasadena and Beverly Hills, according to Karl Deppe, a senior engineer with the Los Angeles Building and Safety Department.
The studies authorized by the council Tuesday are preliminary measures estimated to cost property owners between $1,000 and $4,000 per building. The studies consist of an analysis by a state-licensed structural engineer of the building plans and tests of the strength of the building’s bearing walls based on one or two sites on each wall. The procedure takes at most a few days.
As part of its compliance with the 1986 law, the council ordered environmental impact studies to clear the way for any eventual corrective program that is adopted. The environmental studies are expected to cost the city $40,000 to $60,000. The six-month timetable for seismic studies means that the city will not meet the Jan. 1 state deadline, but the law contains no late penalty.