The Effect of Strong Column-Weak Beam Ratio on the Collapse Behaviour of Reinforced Concrete Moment Frames Subjected to Near-Field Earthquakes

Buildings are found to be more vulnerable in near-fault regions such that they should be designed with higher strength. In this study, the importance of pulse period and peak ground velocity on the efficiency of the strong column-weak beam ratio (SCWBR) is evaluated through incremental nonlinear dynamic analysis. This work involved two aspects: improving the collapse capacity of structures and mitigation of column damage. Three 4, 8, and 12 story moment frames with varying SCWBR (from 1.2 to 3.0) are subjected to two sets of 44 far-fault and 91 near-fault ground motions. Plastic rotation of elements is utilized as a damage measure for beams and columns. The results demonstrate that idealization of collapse mechanism and early yielding of base columns are controlling factors for the 4 and 12 story buildings, respectively, in particular under long-pulse periods. Moreover, the 8 story (mid-rise) building obtains the highest improvement in the collapse capacity (up to 90%) by the increase of the SCWBR. The most dispersion in the efficiency of the SCWBR among short and large pulse period is observed for the 12 story (high-rise) building. It is also observed that the height-wise distribution of the SCWBR is significantly affected by variation in the pulse period and building height