Investigation of the angle formed in irregular structures on their seismic behavior

Abstract

The design of structures with re-entrant angle is often the consequence of the functional, architectural or urbanistic requirement. With any form building, the engineer has full responsibility to ensure the safety of the users and the structure in the case of the earthquake. However, re-entrant angle structures have geometric dissymmetry and limited choice in the disposition of rigid structural elements. The objective of this work is to evaluate the effect of the angle formed between the two wings of an L-shaped building, softened by a transition on their dynamic behavior. Different variants were considered by taking several angle values (45°, 60°, 75°, 90°, 105°, 120° and 135°). In order to evaluate the impact of the analyzed parameter, a study of the linear and non-linear dynamic behavior of the different structures was executed by the spectral modal analysis method and the non-linear static analysis. According to the atypical geometrical configuration in the plan of the various structures, six principal seismic directions were considered Ex, Ey, Ex’, Ey’, Ex” and Ey”. The results show that seismic excitation applied on the transition zone of a building with projected parts occurs a higher deformability. In addition, along this seismic direction, the progressive pushing of a uniform lateral loading applied on the structure with a projections opening angle of 90° assures a better nonlinear behavior in terms of base shears bearing capacity, deformation ductility and damage level.

Keywords

• re-entrant corner
• seismic incident angle
• irregular structure
• response spectrum analysis
• pushover analysis