Performance of various connection system for IBS structure subjected to cyclic load

Nowadays, application of precast constructions is increasing, due to benefit of the industrialized building systems, specially the performance of this type of construction structures when effects of dynamic loads are considered. Precast beam column connection is mostly the critical part in the structures to resist the loads, so that the attention must be paid while designing such connections. Therefore, the aim of this study is to evaluate the efficiency of the precast concrete beam–column connection comparing with the conventional joints. Three-dimensional nonlinear analysis was conducted using finite element method with five beam–column connections under the effect of cyclic load, bearing pad, steel dowel, and steel angle cleat were used to improve the connections performance. The results indicated that the using of steel angle cleat and dowel together and doubling angle cleat have improved the lateral resistance of the precast connections as well as the lateral stiffness and the ability to dissipate damage energy when comparing with the conventional joint performance

A low computational cost seismic analyses framework for 3D tunnel-form building structures

Numerical modeling of tunnel-form buildings entails the utilization of 3D finite element models consisting of large numbers of shell and fiber elements. Accordingly, the non-linear analysis of such models under seismic excitations is both time-consuming and computationally expensive, especially in the case of large scale structures. To address this challenge, this study investigates the efficiency of the Endurance Time Method (ETM) to evaluate the structural responses, location of damage initiation, and the overall performance of tunnel-form structures under the Design Basis Earthquake (DBE) hazard level. Comparison with results derived from pushover and time-history analyses indicated the acceptable accuracy of ETM with significantly less computational efforts. The computation time required for the ETM was less than 25% of pushover (until total failure of the system) and time history analyses on the five- and ten-story tunnel-form buildings. The maximum differences between the results of ETM and time history analysis used to estimate the story drifts and shear forces were 4–6% and 1–4.5%, respectively. Considering the reliability of ETM and its appropriate accuracy, this method can be considered as a suitable alternative to the conventional methods to provide a low computational cost seismic analyses framework for non-linear tunnel-form buildings and similar structural systems