Seismic performance assessment based on the interstory drift of steel buildings

The seismic regulations for the seismic performance assessment of buildings use the maximum interstory drift, theta(max), as a measure to control damage. This article presents a study of the seismic performance based on the theta(max) for steel buildings using Mexico's regulations and the RISK-UE and HAZUS guidelines. The capacity spectrum method is used to evaluate the performance of buildings with 3 different heights located in 4 cities in Mexico with different seismicity, as well as for soft and rock soil types. The HAZUS criterion is conservative in its assement of damage, while the RISK-UE criterion is more in line with the expected damage. The service state, S-state, and the collapse prevention state, CPstate, in Mexico's regulations are suitable for damage control, and are consistent with the damage proposed by the RISK-UE guidelines. In very high seismicity zones, the CPstate for seismic actions equal to or greater than the expected, prevent building collapse; however, significant damage to buildings can still occur. The theta(max) of the CPstate must be established for different seismic intensities and not only for building types.