COLLAPSE CAPACITY ASSESSMENT OFREGULAR TALL BUILDINGS UNDER PULSE LIKE NEAR FIELD GROUND MOTIONS

Structural response to near f ault ground motions has received significant attention in recent years. Such ground motions are different from ordinary ones and are characterized by a large, long period, velocity pulse caused by the forward direct ivity. These velocity pulses could potentially im pose sever demands on structures and increase their risk o f seismic collapse. The situation could even be worse for tall buildings with fundamental periods close to the period of the velocity pulses, and requires special consideration in design process. Besides, Prediction of seismic-induced collapse potential of structu res has been among the main concerns in Performance Ba sed Earthquake Engineering (PBEE). The results could be used as an important measure in designing neww structures, or evaluating the seismic performan ce of existing ones. Not surprisingly, much effort has been made in accurate prediction of collapse capacity of structures due to its importance in estimation of the hum an and monetary losses during and after an eart hquake episode.Collapse assesment of structure under near f ault directivity excitation shows a higher value than expcted by the code which is 1% in 50 years but in th e the case of the farfield suites the resualt are almost consistent with thedesign collpase level defined by the code.

Keywords:

Collapse Capacity , Tall Buildings , Pulse-Like Ground Motions , Forward Directivity ,