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Wednesday, Oct 4, 2023

Negative Effects Can Be Minimized By Staying Informed

Seismic Code Changes Increase Construction Costs

Recent changes to the Uniform Building Code for future development and renovation projects in San Diego, as well as statewide, will likely have a far greater impact on construction costs than most people are aware. Knowledge of these codes and their applications could mean the difference between a successful or marginally profitable project.

The UBC is published by the International Conference of Building Officials and sets standards for the regulation of all building construction in 12 Western states. Every three years, the ICBO updates the code, which is then reviewed by cities and other municipalities in member states for local changes and suggestions.

The UBC was last updated in 1997, and adopted July 1, 1999. While many changes were made to all areas of the code, the most substantial changes were those affecting seismic design requirements because of the 1994 Northridge earthquake.

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These seismic design changes are going to mostly affect building owners and developers by way of increased construction costs. For example: whereas before July 1, a building may have required a design for 10,000 pounds of seismic force, now the same building could be requiring a design for 20,000 pounds of seismic force.

This means using more reinforcing steel to increase strength for concrete and masonry buildings, larger steel sections in steel-framed buildings, and larger design forces for wood-framed buildings , all of which add material and labor cost to the project. The structural design fees will also increase slightly, as more time needs to be spent engineering the building.

– Everyone Is Affected

By The Code Changes

While construction costs are mostly increasing in seismic zones where buildings are located close to a fault line in states west of the Rocky Mountains, the Eastern states are affected as well.

Seismicity had previously been ignored in states east of the Rocky Mountains. Now, the Southern Building Code Congress and the Building Officials & Code Administrators , which are another two organizations that govern construction standards in the rest of the United States , have also adopted seismic designs as part of their building codes.

Before 1999, buildings located in the Eastern states were structurally designed for wind loads. Now engineers have to provide seismic design too. Many of these engineers are not experienced with seismic design techniques. This is going to require a large readjustment by owners and designers in these areas of the United States.

In addition, these new seismic requirements are not only going to affect new construction, but major renovations as well. If a building owner wants to do a major renovation, for example, and there will be a change in occupancy, the owner will need to make sure it has the funds to bring the entire building up to current code standards. This will include the design of an increase in seismic force.

Let’s say someone has a 15-year-old building. Although it used to be considered in Seismic Zone Three, it now falls under Seismic Zone Four. If the owner were to do a major renovation of the building, he would have to bring it up to Seismic Zone Four requirements.

How this is affecting owners and developers in San Diego is illustrated by one case in Mission Valley. A developer was going to purchase a 12-story office building in and convert it into apartments. Because converting it into an apartment building would mean a change in occupancy, the building would have needed an extensive renovation to satisfy the new seismic requirements. It cost too much money, so the developer decided not to purchase the property.

– True Impact On Costs

Remains To Be Seen

Many effects of the new code have yet to be determined. Early on, experts were predicting that the cost of construction most likely wouldn’t increase more than 5 percent. Some developers are already seeing a cost increase of 10 percent, and many believe that for some buildings, construction costs could go up as much as 20 percent.

The cost increases are still difficult to predict because the new code applies to buildings for which the plans were submitted for permitting after July 1, 1999. This brings to mind another problem some developers faced in San Diego. While many architects and developers were rushing to get their plans done , many submitting plans that were not quite done just to get them into the pipeline before the deadline , others ended up having to go back to redesign because the building

didn’t get submitted in time.

With the building codes being updated every three years, by the time a standard is adopted, it goes up for review again.

The best option a developer or property owner has to avoid any negative impacts of these ever-changing codes is to become more familiar with them. Consult an architect or a qualified engineer who can offer seismic resistant evaluation, design and retrofit consultation.

This year, the three standard-setting organizations will merge and become the International Building Code. The new group will set the standard for regulation of all building construction not only in the United States, but in many other countries as well.

Northcutt is president and founder of Structural Technology Consultants, providing structural engineering, signage engineering, seismic retrofit design and expert witness service for projects throughout the United States.


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