الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The present research is concerned with the development of finite element tequnique for nonlinear analysis of dimensional reinforced concrete structures subjected to cyclic reversed loading of earthquake type. Rtional and comperensive constitutive hysteretic models are proposed for simulating the cycle behaviour of concrete and steel in which material nonlinearities in compression, tension , shear and bond response are included. Main emphasis was directed to the modeling of aggrement interlock and dowel bar shear transfer mechanisms in cracked concrete. Strength and stiffness degradation induced by load cycling is also taken into consideration. The structural response under monotonic static loading is reproduced from the cylic reversed loading case as a unidirectionally increasing loading case. The constitutive models are demonstrated by using a finite element program to successfully predict the behavior of highly nonlinear response of reinforced concrete structures for which experimental results were obtained from literature.
Using nonlinear strai-induced orthotropic material concept cobined with appropriate wquivalent uniaxial stress-strain law and Kupfer`s biaxial strength envelope, a proposed constitutive model for uncracked concrete is formulated. Strength, stiffness and ductility changes due to biaxil stress state and cyclic loading-induced damage are accommodated. The concrete cracking considered by the smeared crack approach in conjunction with a fracture energy-based tension softening rule and control parameters to moitor cracks initiation and propagation under load reversals. The advanced shear model, proposed on the basis of Walraven`s two phase model and Eleiott`s model, is successfully simulating the aggregate interlock and dowel action mechanisms under cyclic loading by interducing empirical shear stiffness degradation factors. The elastopiastic model with bilinear stress-strain relation is employed for the cyclic behavior of renforcing steel. The model also accounts for the effect of bond-slip.
The constitutive laws are incorporated into a proposed finite element computer program which utilizes 8-node plane isoparametric elements for.