NORTHRIDGE — For almost a month, they chain-sawed and crow-barred their way into the flattened walls of the Northridge Meadows Apartments, where 16 people died in the Jan. 17 Northridge earthquake.
In a pathos-filled exercise in urban archeology conducted amid the litter of rotting food, crushed automobiles and scattered memorabilia, dozens of lawyers, engineers and city building specialists picked apart the rubble, seeking to learn why the three-story complex collapsed.
Attorneys representing former tenants and families of the deceased found what they allege to be design flaws and construction defects from the foundation to the roof of the 163-unit complex. Poorly secured stucco, missing shear walls, skimpy nailing, undersized connectors and materials substitutions showed a pattern of shoddy workmanship, they contend.
Although conceding the existence of some such defects, experts for the defendants downplayed their significance. They said the 25-year-old building met the standards of its time, and was largely a victim of geography, standing nearly above the epicenter amid a cluster of heavily damaged or destroyed apartment buildings.
"It's a simple case, infuriatingly simple," said Seb Ficcadenti, engineer for Northridge Meadows' builder, Heller Construction. "A couple hundred yards around the site, five buildings with partial collapse."
Beyond the pretrial posturing, however, the board-by-board dismantling of Northridge Meadows--conducted under court order and costing an estimated $500,000-- produced some lessons that are widely accepted.
Foremost is the inadequacy of building codes for two- and three-story wooden structures. The inspection showed that even today's standards, though tougher than those of 25 years ago, fail to provide the level of safety they should, Los Angeles building officials have concluded.
Secondly, the building that killed 16 people was not a lot different from other buildings that survived the Jan. 17 quake, suggesting that there could be a loss of life in future earthquakes.
"There was nothing different," said Nicolino Delli Quadri, chief of the Training & Emergency Management division of the Los Angeles Department of Building and Safety. "Typical construction for that time. There's nothing at this time that we found atypical."
The common ground is that the causes of the Northridge Meadows failure include inadequate seismic resistance built into the walls and over-reliance on structural elements that have been shown to provide less strength than was thought in 1970. Not only are such flaws endemic to buildings of that era, but, in some cases, today's code still allows them.
Delli Quadri, spokesman for the Department of Building and Safety's post-earthquake analysis team, is also a member of the committee examining wood frame construction. He said the group is preparing recommendations for further tightening of the code for new buildings and a program to strengthen older buildings.
If adopted, a retrofit program would require the owners of hundreds--and possibly thousands--of buildings of the early 1970s and before to remove gypsum board or similar outdated materials from critical walls and resurface them with stronger materials such as plywood.
"A lot of us in the building department had a high confidence in wood frame buildings," Delli Quadri said. Now, they are "looking back, asking questions about the buildings we approved in the past. How safe are they? They could be safer."
Although the final analysis of what made most of the first floor of Northridge Meadows collapse must await extensive calculations based on the data collected over the past month, several of the experts now agree on a rough explanation.
They say its design relied upon a medley of structural elements to work together in the building's shear-wall system of seismic resistance: stucco exterior walls, diagonal wood bracing, gypsum board interior walls, plywood walls and a partial steel frame.
But most of those building materials were inherently weaker than the strength ratings they were then given in the building code, and, reacting differently to the stresses, the weaker elements failed first, increasing pressure on the stronger ones, several of the experts said.
"The code allowed the architect to put in stucco, drywall, plywood," Delli Quadri said. "The stucco and drywall gave up. The rest of the load went into plywood panels. Overwhelmed, they failed."
As litigation progresses, the questions attorneys raise about Northridge Meadows will most likely focus narrowly on the building standards of 1970: Did the design satisfy the requirements of the code? Did the builder follow the design?
Joel Castro, the lead attorney in a tangle of lawsuits filed by several tenants and the families of dead tenants, asserted that the evidence resoundingly answers both questions no.
As his experts wrapped up their inspection late last month, Castro presented their findings as a catalogue of flaws.