Angular Earthquake Coefficient in Irregular Structures on Plan

Subject Areas : Analysis of Structure and Earthquake

Mohammad reza Bahari ¹ , Alireza faroughi ² , mohammad ghanoonibagha ³

1 - Islamic Azad Univercity/ East Tehran Branch/Tehran/iran
2 - civil,technical and engineering,islamic azad east tehran,tehran,iran
3 - دانشگاه آزاد-تهران شرق

Received: 2017-04-17 Accepted : 2017-06-14 Published : 2017-05-22

Keywords: ductility, Angular earthquake coefficient, Angular behavior coefficient, Angular Period of time, Added Strength coefficient,

Abstract :

Today is a common method of seismic design of structures in the regulations are based on the static method equivalent and Determine the base shear design by using The linear spectrum. To determine the base shear, a coefficient called earthquake coefficient is used. In this article first, Methods of calculation and factors affecting the behavior of factors are investigated. Then a number of steel structures with lateral load systems MRF and CBF, with the number of floors 3, 7 and 10 Irregular on the plan is evaluated. By performing a non-linear static analysis under the influence of lateral loads، Ductility and their coefficient of resistance in different angles Due to the limitation of local ductility in structural elements (Based on maximum drift) and  finally the behavior coefficients (Given the values obtained from the analysis) will be counted. It is assumed that the angular behavior coefficients follow a rectangular rule so that the values of the angular behavior coefficient with the length of the line from the origin with the desired angle in a rectangle whose sides are the coefficient of behavior of the main structure of the structure is equal. Then, the values of the angular behavior coefficient obtained from this rule are compared with the values obtained from nonlinear static analysis. According to the results, it is also observed that the angular behavior coefficients obtained from this type of analysis are slightly higher than their values from the rectangular base, and follow this rule well. As well as structures at these angles relative to the main directions shows better behavior.