Quake hazards may force Las Vegas building costs up

Jennifer Robison

Monday, April 29, 2002 | 11:27 a.m.

A national program designed to unify construction codes and reduce earthquake hazards will demand strengthened building standards in parts of Southern Nevada.

The changes could add to construction costs for homes and megaresorts alike, and might also reshape future development in Southern Nevada, say public officials and private engineers.

"Buildings will need to be able to move and dissipate (earthquake) energy more than current codes require," said Steve Schiller, director of operations for the engineering firm of Martin & Peltyn Inc. "This will probably have more of an effect on taller buildings. The small, light building will not be as drastically affected."

The Clark County Building Department wants to adopt the new code, which some states across the country have already adopted, as early as the end of the third quarter.

"The three (national) builders' code organizations sat down and looked at all the current standards together," said Neil Opfer, an associate professor in the construction management program at the University of Nevada-Las Vegas. "One of the things that came to the forefront was the upgrading of seismic standards.

"Even before this international building code, there was talk that Las Vegas was too low (in seismic standards). I remember conversations three or four years ago that they would be upgrading. That's been the general trend."

Under 1997 Uniform Building Code standards, Southern Nevada lies within seismic zone 2B, which means the area could sustain moderate earthquake damage.

Upon adoption of the 2000 International Building Code, Southern Nevada would be classified as the equivalent of zone 3, a region in which major earthquake damage is possible. Officials said there has been no new recent discovery of local earthquake hazards, and the area is being reclassified as part of a gradual change in the way seismic hazards are viewed.

Much of northwestern Nevada is already classified in zone 3, and parts of the state lie within zone 4, which means major fault lines are nearby.

California is also split entirely between zones 3 and 4.

Though Southern Nevada will be classified within zone 3, those familiar with the code changes say the new code allows building codes to be applied in a more site-specific way.

That means, depending on a parcel's soil type and its proximity to fault lines, builders might not notice a serious upgrade in structural standards.

"The seismic source being considered is out by Hoover Dam," Schiller said. "That's what's driving the changes in seismicity (the frequency and strength of earthquakes). The new code is going to be more site-specific than the existing code, so different parts of the valley could have different force levels and different (structural) requirements."

Schiller said the type of construction will also affect the extent to which a building will need to adopt stricter structural standards.

Most buildings in the valley are currently designed using shear walls -- stiff concrete walls -- for earthquake resistance.

Under the new seismic activity classification, Schiller said buildings more than 160 feet tall -- or about 16 stories -- would need to be constructed using ductile framing systems, which are a combination of columns and beams.

For these and other developments, boosted seismic codes will translate into higher construction costs. But public officials and private engineers alike have a hard time predicting exact cost increases.

"It'll be more expensive in terms of construction costs, and it will probably take longer to build, so construction schedules will probably be affected," Schiller said. "But we don't know how much longer it will take, or how much more it will cost to build."

A county official echoed Schiller's uncertainty.

"Every site is unique," said Ron Lynn, acting director of the Clark County Building Department. "Engineers will have to look at soils, spectral response (how a building reacts to quakes) and the type of the building."

For any type of building -- from single-family home to 25-story megaresort -- framing is the most costly construction component, accounting for about 15 percent of a building's cost, Opfer said.

The need for stronger shear walls and wall hold-downs may boost the cost of framing less than 1 percent on a residential home, Opfer said. But even a small increase in the cost of a home could could spell trouble for home builders who, already pressured by rising land costs and impact fees, have raised new home prices to a point where the median price is pushing $180,000.

For a 20-story hotel, Opfer said, the cost of framing would increase more noticeably -- perhaps 2 to 3 percent.

Lynn said the county has taken its time to adopt the 2000 international standards so engineers would have time to familiarize themselves with the new code and offer comments to the building department.

"We don't see a major disruption by the adoption of the code, but until we go through several projects and several types of projects, we don't know exactly what the impact will be," Lynn said.

Though the county would like to adopt the new code by the end of the third quarter, not all the valley's public agencies have the same plan.

The state does not mandate adoption of specific codes, but rather leaves those decisions to local jurisdictions. So it's conceivable the county will have a set of codes that differs from those of area cities.

Mohammad Jadid, manager of plans examination for the city of Henderson's building department, said the city is "shooting for the same target, though it may be closer to the beginning of the fourth quarter" before Henderson implements the code changes.

An official at the city of North Las Vegas said he is uncertain when the city's building department might begin using the new code.

"If issues about local amendments and changes in the international building code are acceptable or worked out in a timely fashion to allow adoption within that timeframe, then we'll certainly do so," said Jim Stubler, acting development services director for the building department of the city of North Las Vegas. "But we need sufficient review time for (code) amendments."

Paul Wilkins, deputy director of the building department for the city of Las Vegas, said the city is still considering whether it would adopt the new code.

"I have concerns about the code being adopted so soon," Wilkins said.

He said the 2000 version of the international code will be replaced by a 2003 version, and the city may simply wait and use the upcoming version instead.