الفهرس 
Thesis organizationOnly 14 pages are availabe for public view
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Abstract
Many structures in the present days have irregular geometries in both elevation and plan. Past earthquake studies show that buildings suffer severe destruction during earthquakes due to torsional irregularity.
When and how to consider torsion effects are depended on the criterion and relative restrictions for torsional irregularity. Relationship between the level of irregularity and the change in behavior could established which allows guidance as to
a) When the effect of structural irregularity can be neglected, and
b) The demands change for different degrees of structural irregularity.
Provisions in different earthquake codes about torsional irregularity are presented. This study is tended to define the influence of different degrees of irregularity on structures designed for earthquake by investigation torsional irregularity behavior of different irregular structures using simplified analysis.
At first focuses in reviewing of reported research studies indication that the irregularity has been computed in terms of magnitude ignoring the effect of location of irregularity. However, location of irregularity has a significant influence on the seismic response.
Also, reviews of seismic design codes and precautions for the design of RC structures with structural irregularity which appears in the most of the international codes for concrete buildings design.
Also, focuses on studying the complex behavior of structure under asymmetric form; a study on the influence of the torsional moment effects on the behavior of structure is done by using Response spectrum method. Results are compared and precautions are assumed to avoid damages caused by torsional irregularity under earthquake loads.
Also, Inelastic investigation has been assumed to determine capacity of irregular structures due to seismic load to reach collapse case, find the irregularity relation with successive plastic hinges formations in structural elements and determined response reductions factor for different irregular structures to assess the relation with irregularity level.
The results presents that buildings with severe irregularity are more suffering than those with regular or less irregularity resulting from torsion behavior, plastic hinges formation in structural elements rapidly formed with increasing irregularity level Also, Response reduction factor varies with irregularity level which as irregularity degree increase, the force reduction factor decrease to values less than value recommended in Egyptian code (ECP-201) which constant value “5”.