Project Description

Soft Story Seismic Retrofit – Buchanan St


Installation of UFP plates in tight crawl space access

Installation of drag tie in crawl space

Foundation Bolt

Installation of hold down and foundation bolt

Installation L 50s at joist and top plates

Moment Frame with Brace (i)

Moment Frame with Brace (ii)

Moment Frame with Brace (iii)

Moment Frame with Brace (iv)

Moment Frame with Brace (v)

Seismic Retrofit for a Soft Story Apartment Building on Buchanan Street

The Challenge: This 3-story wood frame apartment building in San Francisco had a wide footprint, and the seismic retrofit would require the installation of 2 moment frames. It also required bolting the building’s mudsills to the foundation as well as installation of hardware at the wall-to-floor framing and shear wall construction.

The location of one of the proposed moment frames was heavily congested with intersecting utility lines. The installation of the moment frame in this location would have necessitated the relocation of all of the utility lines and some of their meters at a tremendous cost. In our view, one other acceptable location for this moment frame existed, but it would require the relocation of major load bearing members in a very tight access area in the crawl space and the excavation and construction of retaining walls.

Our Solution: The personnel at SteelCore Builders have extensive experience with performing complex operations in tight access and congested locations. Tapping into our vast experience, we produced a cost analysis for the alternative moment frame location and recommended this option to the owner and the structural engineer. After full consideration, the owner and the structural engineer chose to pursue this option, and the structural engineer produced a set of revised plans. SteelCore Builders’ implementation of the retrofit was completed at 40% less cost than the original location consideration.

To discuss your seismic retrofit project, please contact structural builders SteelCore Builders at: 415-331-0525.