IMPACT OF ENGINEERING MODELING ASSUMPTIONS ON ASSESSING SEISMIC RESISTANCE OF MONTGOMERY BLOCK BUILDING

The Montgomery Block building is used as a case study to assess the ef fectiveness of conventional analysis methods commonly used by practici ng engineers throughout North America when conducting seismic evaluati on work to predict the seismic performance of unreinforced masonry (UR M) buildings. This building predominantly constructed of URM pier-and- spandrel facades and URM shear walls was built in 1853 and survived th e 1906 San Francisco Earthquake despite being roughly 15 km from the S an Andreas Fault that ruptured in 1906. It is found that the impact of engineering modeling assumptions can be of nearly an order of magnitu de for buildings of that type, depending on the structural model selec ted by the engineer. Of all the conventional modeling procedures consi dered in this paper, it is found that only the special procedure of th e Uniform Code for Building Conservation (UCBC) comes close to predict ing the observed seismic response. However, some extensions of the mor e conventional modeling procedures are useful in demonstrating the pot entially beneficial period elongation that accompanies structural stre ngth degradation as damage progresses.