IDS Group Making Buildings Safer in Southern California
Shop 1841 is a two-story retail building located in the city of San Gabriel in Southern California. It has about 13,500 sq. ft of retail area including the partial second floor that covers about 1/3 of the building footprint. The original construction of the building goes back to the 1940’s or 50’s and consists of a long span wood truss roof supported by reinforced concrete walls in the retail areas. The building had an addition in the 1970’s where the 2-story portions with wood floors and reinforced CMU walls were added. Most recently, the building was partially remodeled and seismically retrofitted in 2010. The limited retrofit consists of steel moment frames added at the open store front as well as several plywood shear walls added throughout the building. Struts and ties at the ceiling and roof levels have also been provided as part of the 2010 seismic retrofit. The building site is located near a major fault and is classified as highly seismic.
IDS utilized relevant provisions of ASCE 41-13 to evaluate this building. A Tier-1 screening according to Chapter 4 of ASCE 41-13 was performed. The performance level was chosen as Life Safety (LS) according to ASCE41-13 Table 2-1. Apparently due to the seismic upgrade of the building in 2010, no structural deficiencies were detected. A few nonstructural deficiencies related to piping, equipment, and glazing were found. The SP3 seismic performance prediction program by Haselton Baker Risk Groups was used to determine the building’s USRC Ratig. The building obtained 4 stars, 4 stars, and 3 stars for the three dimensions of Safety, Damage, and Recovery respectively. Considering the age of the building and the fact that virtually all types of construction materials have been used in it, namely steel, reinforced concrete, masonry and wood, it’s Silver (4-4-3) Seismic Rating is very impressive.
Much of the credit goes to the owner, Mr. Paul Jenkins of the Star Building Group, whose approach to the mitigation of seismic risk is an outgrowth of his philosophy that earthquakes ought to be viewed and dealt with as a natural part of the local environment. Just like we prepare and protect ourselves and our places of residence/work/school from the effects of hot or cold weather or rain or the strong sun, so should we prepare for earthquakes which are bound to occur in this region without warning.