شبیه سازی رفتار غیر خطی اتصالات بتن مسلح با خم 180 درجه تحت بار محوری متغیر
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شناسه دیجیتال (DOI): 10.22631/ICCECONF.2017.14891.1052
نویسندگان
1میدان امام، کوی اتحاد، بن بست دوم، مجتمع شایان فر
2پژوهشکره شهید ستاری شمال کشور
3هیئت علمی دانشگاه مازندران
4پژوهشکده شهید ستاری شمال کشور
چکیده
In this study, an analytical model for predicting nonlinear behaviour of exterior reinforced concrete (RC) beam-column joints under varying axial load was developed. The main focus was on the assessment of the effect of axial load variations on the response of RC joints. During seismic actions, overturning moments are produced by lateral loads that are translated into axial loads in the column and tensile on one side of the structure as well as compression on the opposite. According to experimental evidence, it can significantly affect nonlinear behaviours, i.e. flexural, shear and axial failure of RC columns, bond mechanism and shear failure of the joints. To simulate and evaluate these nonlinearities, a beam – column joint model including a rotational spring in the joint core and some rotational springs in other parts were developed. The characteristics of joint spring could be computed using principal tensile stress-rotation relation in the joint core. Therefore, for the joints 180°-hook principal tensile stress-rotation relation in the joint core was proposed. A new methodology was also developed to consider the axial load variation effects in determining characteristics of rotational springs. To validate the accuracy and reliability of the analytical model, it was applied to test specimens available in the literature. The results showed that the proposed analytical model would predict the experimental response of poorly detailed RC beam-column joints under varying or constant axial loads with reasonable precision. The simple analytic procedure could make the model sufficiently suitable for practical applications.
کلیدواژه ها
موضوعات
 
Title
Simulation of Nonlinear Behaviour of RC Joints with 180°-hook under Varying Axial Load
Authors
Abstract
In this study, an analytical model for predicting nonlinear behaviour of exterior reinforced concrete (RC) beam-column joints under varying axial load was developed. The main focus was on the assessment of the effect of axial load variations on the response of RC joints. During seismic actions, overturning moments are produced by lateral loads that are translated into axial loads in the column and tensile on one side of the structure as well as compression on the opposite. According to experimental evidence, it can significantly affect nonlinear behaviours, i.e. flexural, shear and axial failure of RC columns, bond mechanism and shear failure of the joints. To simulate and evaluate these nonlinearities, a beam – column joint model including a rotational spring in the joint core and some rotational springs in other parts were developed. The characteristics of joint spring could be computed using principal tensile stress-rotation relation in the joint core. Therefore, for the joints 180°-hook principal tensile stress-rotation relation in the joint core was proposed. A new methodology was also developed to consider the axial load variation effects in determining characteristics of rotational springs. To validate the accuracy and reliability of the analytical model, it was applied to test specimens available in the literature. The results showed that the proposed analytical model would predict the experimental response of poorly detailed RC beam-column joints under varying or constant axial loads with reasonable precision. The simple analytic procedure could make the model sufficiently suitable for practical applications.
Keywords
RC beam-column joints, Axial load variation, Joint shear failure, Analytical model, Principal tensile stresses