Response of High-rise Structures under Static and Dynamic Loadings

Abstract

This study was carried out in the Department of Civil Engineering of Stamford University Bangladesh with the objectives of the response of high-rise structures under static and dynamic loadings and the application of static and dynamic analysis of the structures.

High-rise buildings are exposed to both static and dynamic loads. Depending on the method used and how the structure is modelled in finite element software, the results can vary. Nowadays the world is going forward by the implementation of performance-based engineering analysis. Most of the multi-storied buildings in our country are still analyzed and designed without proper seismic consideration in the conventional way. Under strong earthquake, structures behaved unsatisfactory during major ground motions with large inelastic deformations, and dynamic analysis should be performed for the structure. Dynamic effects such as resonance frequencies and accelerations are considered. The variation in static results from reaction forces, overturning moments, deflections, critical buckling loads, forces between prefabricated elements and force distributions between concrete cores are investigated with different models. The structural dynamics is the direct application in design of high-rise building and structural analysis against earthquake and wind loading. Structural design for dynamic loading is primarily concerned with forces and their effects on motion.

All design against seismic loads must consider the dynamic nature of the load. However, for simple regular structures, analysis by equivalent linear static methods is often sufficient. This is permitted in most codes of practice for regular, low to medium-rise buildings. Equivalent static analysis can therefore work well for low to medium-rise buildings without significant coupled lateral-torsional modes, in which only the first mode in each direction is considered. Tall buildings (say, over 75 m or 25 storied), where second and higher modes can be important, or buildings with torsional effects, are much less suitable for the method, and require dynamic analysis of the buildings.