In order to consider the influence of higher modes on seismic performance of transmission tower,an evaluation method was proposed based on the modal lateral force combination(MLFC) and the capacity spectrum method.The main participating modes were identified according to the higher modal contribution factors,while the lateral force combination patterns were constructed based on the MLFC by taking into account the weighted plus minus combination of each mode.Then the capacity curves and performance indexes for transmission tower were determined by the capacity spectrum method,while seismic performance was evaluated according to the seismic performance targets and performance levels for top displacement.Finally,seismic performance evaluation method for transmission tower which took into account the influence of higher modes was proposed.Case study of engineering project indicates that the capacity curves and performance indexes evaluated by the proposed method agree well with those obtained from the incremental time history analysis method,which demonstrates that the proposed method provides an efficient way to investigate the influence of higher modes on the seismic performance of transmission tower.
Journal of Guangxi University(Natural Science Edition)
modal lateral force combination
capacity spectrum method
seismic performance evaluation