CSUN Garage Builder Wins County Project

In one of the first projects of its kind since the Northridge earthquake, the Los Angeles County Board of Supervisors on Tuesday awarded the first phase of a $19-million contract for a high-rise parking garage to a firm that built the Cal State Northridge parking facility that crumbled in the Jan. 17 quake.

But executives of the winning bidder, A. T. Curd Constructors, and county officials say the new project will be significantly different from the CSUN facility, strengthened by lessons learned in the temblor.

“We can’t in good conscience build them like we used to, knowing what we have learned in the Northridge earthquake,” company President Andrew Curd said.

The company, which will oversee construction of a seven-level, 3,000-car garage at County-USC Medical Center, was the lowest of four bidders on the project.

Bill Stewart, director of the county’s Internal Services Department, which oversees awarding of construction contracts, said all four firms that bid for the contract had been involved to some degree in projects that suffered damage in the Northridge temblor, although some firms disputed that assertion.

Curd said that after the Northridge quake, his engineers have redesigned the county project to improve the flexibility of columns and strengthen walls, two lessons learned from the collapse of the CSUN garage.

“These are significant differences from any (garage) we’ve done in the past,” Curd said.

At the CSUN garage, square supporting columns gave way because they were too brittle to hold up under the pounding and swaying brought on by the earthquake, engineers found.

Curd said the columns to be used at the County-USC garage will be of an octagonal shape and with significantly greater steel reinforcement. Curd said engineers estimate that the new design will enable the structure to withstand four to five times more movement than the old design. The new garage will also have reinforcing shear walls to give the structure greater strength, he said.

Although the changes are not required under the building code, Curd said they are being integrated into the project at his company’s expense, which he estimated to be several hundred thousand dollars.

Stewart said that to ensure that the garage will have the latest improvements and design innovations, the plans will be submitted to two independent peer review committees. The design reviews will also be coordinated with the state’s safety design experts.

“This will be the best-studied parking structure in the history of the Western United States,” Stewart said.

Last week, officials for the state university system adopted changes in construction policies that require the same design improvements being included in the County-USC project.

Arthur Ross, president of the Structural Engineers Assn., whose members have extensively studied damage from the Jan. 17 earthquake, said the planned design changes should make a big difference.

Ross said a second large parking structure on the CSUN campus, which sustained little damage, had shear walls. That, Ross said, may have made the difference.

The 2,500-space CSUN garage that was heavily damaged in the earthquake had neither shear walls nor extra steel reinforcing in its vertical columns.

Structural engineers have long said buildings with shear walls are generally more resistant to earthquake damage.

But designers are often reluctant to use them because they make the buildings less open, and can cause security and ventilation problems.