“Massachusetts was probably the first eastern state to develop a meaningful seismic-design code,” says Joseph Zona, head of structural engineering at Simpson Gumpertz & Heger in Waltham. “Even back in the ’70s, people realized that, even though it was a low probability, the consequences would be devastating if it happened.”
That said, “seismically, the state is in probably decent shape,” says Bob Stevens, senior vice-president of the Boston Society of Civil Engineers. “The building code that’s been in place is probably adequate for the seismic zone that Massachusetts is in. It’s not perfect, but pretty darn good.”
Still, the code recognizes that no building can be indestructible. “[A]bsolute safety and prevention of damage,” it reads, “even in an earthquake event with a reasonable probability of occurrence, cannot be achieved economically for most buildings.”
When it comes to older structures, the code stipulates that, whenever substantial renovations are performed, owners must retrofit the building in order to address structural deficiencies that might be damaged or cause injury during a tremor: reinforcing facades; bolstering old stairways; and bracing lighting, pipes, and ductwork to ceilings.
“We can’t go back in time,” says Rob Anderson, an administrator with the Massachusetts Board of Building Regulations and Standards. “The philosophy of the code is to try to increase the life-safety value of the building incrementally as you are [renovating] the pieces and parts of that building.”
The goal, says Zona, is “not so much to protect the average building from being damaged, but to protect the people inside. To spend a modest amount more so the building would stand and people could get out. Even an office building designed to the latest building code might be badly damaged in an earthquake. They might even decide to tear it down.”
Our worst fears
There’s plenty else to worry about in a city like this. Assuming it ever gets completed, for instance, what would happen to the proposed Boston University Biolab, sitting on soft South End landfill, its Petri dishes populated with Marburg virus and plague, should the walls start shaking?
Ellen Berlin, the director of corporate communications for BU Medical Center, promises that “the lab is designed to appropriately withstand an earthquake. Seismic events were taken into account during the planning.”
In particular, she says, special attention was paid to safeguarding against progressive collapse — the pancaking of vertical floors seen most infamously in the World Trade Center. “Part of it could collapse, but it wouldn’t destroy the whole building.” Moreover, the most dangerous germs would be handled only deep within the concrete structure, protected by several successive layers of walls.
And what about the Big Dig? The tragic death of Milena Del Valle — never mind the litany of leaks — suggests it would hardly take a magnitude 7 earthquake to compromise those tunnels’ structural integrity.
“The Big Dig was built to withstand earthquake shaking approximately three times as large as what the building code addresses,” says Ebel.
But on the downside, he reminds us, “a few years ago we had that major leak where one of the walls buckled because they’d had a void in the concrete and the pressure of the water kept pushing on the wall and eventually broke through and flooded one of the tunnels. If there are more such weaknesses in the tunnel, maybe the shaking would be enough to push water into another one of the voids and flood the tunnel again. It’s certainly something to think about.”