Enhancing the Progressive Collapse Resistance of Seismically Designed Steel-Concrete Composite Buildings

The present work studies the requirement of steel concrete buildings to sustain (a) seismic excitations without the development of extensive inter-storey drift, which would indicate the potential for collapse and (b) failure in structural elements due to accidental actions, without the disproportionate propagation of damage to the elements which were not affected directly by the initial cause. As the latter is an additional design requirement, an increase to the total structural cost is inevitable. Therefore, an engineer is required to put significant effort in the limitation of the particular increase, ensuring at the same time the desirable structural performance.
Use of automatic optimization algorithms is a valuable tool for this purpose. However, the same goal might be pursued using manual strategies instead of random search using one’s experience. Four manual strategies are proposed in order to improve the collapse-resistance of steel-concrete composite buildings already designed against earthquake. The effectiveness of the aforementioned strategies is assessed in comparison with the design defined using an optimization algorithm.