Following a Tuesday night press conference where Sunroad Enterprises announced it has agreed to reducing the height of its 180-foot office building near Montgomery Field, the issue of how to shrink the building's height -- by as much as 20 feet -- has come to the forefront.
The reduction is to comply with Federal Aviation Administration height limits, because the building is deemed too near the airfield to be 180 feet.
"Its really going to come down to what is the safest and most cost effective way (to accomplish this task). There's multiple options on the table," said Don Adair, manager of the San Diego division of Swinerton Builders, who is the general contractor on the project.
Swinerton, along with the project's architect (Brian Paul & Associates), structural engineer (Hope Engineering) and building owner (Sunroad)are currently in the process of determining what option would be acceptable.
Adair said they have been given no deadline as to when the reduction must be complete.
According to several structural engineers contacted, besides the unlikely option of demolishing the building and reconstructing it from the ground up, there are two options the building's construction team can utilize.
According to Christopher Kamp, vice president of SDSE Structural Engineers and president of Structural Engineers Association of San Diego, one option would involve removing the top 20 feet of the building by dismantling the exterior cladding, glazing, mechanical equipment, floors and steel beams and columns.
The dismantled pieces of the building would then be transferred to the ground via crane.
If this option were selected, Kamp said the building's project team would have to dismantle several additional floors of the building if the owner wants the project to have the same look as originally planned, as the roof and what will now be the top floors would need to be reconstructed and possibly redesigned.
"The architect has to re-look at it (the project) now," Kamp said.
The other option involves shoring the building and propping the top floor of the building up on a jack system, which would eliminate the need to redesign the top of the structure.
Once this is accomplished, workers would dismantle several of the building's middle floors prior to the top of the building being removed from the jacks and lowered down onto the existing structure.
"I've never heard of that being done before," Kamp added.
In both options the mechanical equipment atop the building and any elevator related equipment would be removed first, which represents one of the more difficult steps in the process, according to John Walsh, president of Walsh Structural Engineers.
Exterior cladding and glazing would then be removed prior to the floors, columns and beams.
Regardless of what option the project's team chooses the "time, expense and effort to reduce the height will be considerable," according to a Sunroad release.
Cutting the building down in height by as much as 20 feet would have a positive effect on the structure in terms of its resistance to seismic force, according to Walsh, who said he's been involved in projects where aging building's seismic performance is upgraded by decreasing building height.
Sunroad agreeing to reduce the building's height comes less than a week after San Diego Mayor Jerry Sanders issued a directive to Sunroad to immediately comply with a stop-work order on the entire building, and submit plans to remove the top two stories of the building.
Since October 2006, three stop-work orders have been issued to Sunroad.
The first order was amended in December 2006 to allow for weatherproofing. A second stop-work order was issued in May, after Sanders said it became clear Sunroad was doing more than just weatherproofing.