Fitting seismic upgrades into a comprehensive retrofit
Although the building was tired and dated, the location was excellent and the site offered numerous amenities that would have been expensive to assemble otherwise. As a condition of the sale, the city required the purchaser to implement significant seismic upgrades to the building. The eventual purchaser, iQ Credit Union, a non-profit financial services organization, was seeking a prominent downtown location. It put the site under contract and undertook a due diligence study. The study evaluated the scope of necessary seismic upgrades and overall building renovations to ensure the building would be suitable for use as a headquarters.
“In this region, there is an impetus for reusing existing buildings. The cost of the overall project was probably about equivalent to what it would have cost if we built from the ground up. That is, if we had found bare land, which is difficult.”
-Jim Morrell, iQ Credit Union
Jim Morrell, senior vice president of support services and chief information officer at iQ, said assembling a team of experts was the first step. “There was a bit of an unknown factor,” Morrell said. “We knew nothing about seismic retrofits. To make us more comfortable, we conducted a lot of site visits and interviews” with firms who could do the work.
Ultimately, the Seattle-based architectural firm EHS Design Inc. was hired to lead the due diligence effort in conjunction with a local general contractor, Team Construction Inc. Collaboration between design and construction professionals was critical since re-envisioning the facility was required and renovation costs would be significant and difficult to quantify. Morrell said much though went into finding the right partners, adding that working with EHS Design, Team Construction and the other project principals helped him understand more about seismic retrofits than he ever imagined he would.
“In this region, there is an impetus for reusing existing buildings,” Morrell said. “The cost of the overall project was probably about equivalent to what it would have cost if we built from the ground up. That is, if we had found bare land, which is difficult.” The location was strategic for its visibility and marketability, Morrell said, and iQ was able to take a building “that wasn’t necessarily a downtown landmark and turn it into a landmark.”
The project team developed conceptual strategies for the site and building. A wide range of options were explored, presented, refined and tested. A preferred option was selected by iQ’s executives and board of directors, and the team developed a comprehensive conceptual design strategy and cost model. A coordinated effort was critical given the multitude of proposed retrofits.
“Successful implementation of the seismic upgrades required very close collaboration of the project team” said Curtis Bales, project manager for EHS Design. “Literally every penetration which was made in the existing structure to accommodate the new building systems needed to be defined and negotiated per structural requirements. For example, the new curtain wall window system was fastened through the [reinforcing column wrap] back to the concrete column. The quantity and spacing of the fasteners was defined to ensure the seismic wrap was not compromised and that the window system was securely fastened.”
Opening a door
The seismic upgrade stipulation by the city actually allowed the team to look at a much more comprehensive renovation of the building as a whole. “The city requirement … opened the door to making other needed improvements,” said Bales. “The need to access the entire structural concrete frame for seismic upgrades required the demolition and replacement of the existing single pane and leaking glazing system.”
Roggenkamp said when an existing building is being renovated and given “new life,” as opposed to being razed for a replacement building, seismic retrofits are vital to provide upgraded protection for the renovated building against earthquakes.
“Upgrading an existing structure to increase seismic resistance begins with understanding how best to utilize the existing seismic resistance of the structure, thus minimizing the physical amount of retrofit work required,” Roggenkamp said, adding that retrofits should build on existing seismic capacity. “Obviously, these constraints are not encountered in the design of a new building.”