1,721,530 research outputs found
Thermodynamic and Spectroscopic Analysis of Pure and Mixed Gas Hydrates Formed in Porous Media
No full textMaterial nonlinear analysis of RC shear walls subject to monotonic loadings
No full textThis paper proposes an analytical model to simulate the nonlinear behavior of reinforced concrete (RC) structures subject to monotonic in-plane shear and normal stresses. Based on the force equilibrium, compatibility conditions, and bond stress-slip relationship between the reinforcement and the surrounding concrete, a criterion to consider the tension-stiffening effect is proposed using the concept of average stresses and strains. The material behavior of concrete is described by an orthotropic constitutive relation, focusing on the tension-compression region with tension-stiffening and compression softening effects defining the equivalent uniaxial stress-strain relation in the axes of orthotropy. The behavior of cracked concrete is described by a system of orthogonal cracks, which follows the principal strain directions and rotates according to the loading history. Finally, correlation studies between analytical results and available experimental data are conducted to assess the validity of the proposed models. (C) 2004 Elsevier Ltd. All rights reserved.The research reported in this paper was made possible
bythe financial support from the Smart Infra-
Structure TechnologyCent er funded bythe Korea
Science and Engineering Foundation. The authors
would like to express their gratitude to this organization
for the financial support
FE analysis of RC shear walls subject to monotonic loading
No full textThis paper describes the implementation of an orthotropic concrete model in a non-linear finite-element analysis Of reinforced concrete structures subject to monotonic in-plane shear Based on the force equilibria, compatibility conditions, and bond stress-slip relationship between the reinforcement and the surrounding concrete, a criterion for considering the tension-stiffening effect is proposed, using the concept of average stresses and strains. The material behaviour of concrete is described by an orthotropic constitutive relation, focusing on the tension compression region with tension-stiffening and compression-softening effects defining the equivalent uniaxial stress-strain relation in the axes of orthotropy. The behaviour of cracked concrete is described by a system of orthogonal cracks, which follows the principal strain directions and rotates according to the loading histoty. Finally, correlation studies between analytical results and available experimental data are conducted to assess the validity of the proposed models.The research reported in this paper was made possible by the financial support from the Smart Infra-Structure Technology Center funded by the Korea Science and Engineering Foundation. The authors would like to express their gratitude to this organisation for the financial support
Material nonlinear analysis of RC shear walls subject to cyclic loadings
No full textThis paper describes an extension of a numerical model, which was developed to simulate the nonlinear behavior of reinforced concrete (RC) structures subject to monotonic in-plane shear and introduced in the companion paper. The extended model is intended to simulate the behavior of RC structures under cyclic loadings. While maintaining all the basic assumptions adopted in defining the constitutive relations of concrete under monotonic loadings, a hysteretic stress-strain relation of concrete, which crosses the tension-compression region, is defined. In addition, unlike previous simplified hysteretic stress-strain relations, curved unloading and reloading branches inferred from the stress-strain relation of steel considering the Bauschinger effect are used. Modifications of the stress-strain relation of concrete and steel are also introduced to reflect a pinching effect depending on the shear span ratio and to represent an average stress distribution in a cracked RC element, respectively. Finally, correlation studies between analytical results and experimental studies are conducted to establish the validity of the proposed model. (C) 2004 Elsevier Ltd. All rights reserved.The research reported in this paper was made possible
by the financial support from the Smart Infra-
Structure Technology Center funded by the Korea
Science and Engineering Foundation. The authors
would like to express their gratitude to this organization
for the financial support
Nonlinear analysis of RC shear walls considering tension-stiffening effect
No full textAn analytical model which can simulate the nonlinear behavior of reinforced concrete (RC) structures (such as panels and shear walls) subjected to in-plane shear and normal stresses is introduced. Based on the concept of equivalent uniaxial strain. constitutive relations of concrete are presented in the axes of orthotropy which coincide with the principal axes of total strain and rotate according to the loading history. The proposed model includes the description of biaxial failure criteria which show compressive strength enhancement and tensile resistance reduction effects for the stress states of biaxial compression and tension-compression, respectively. After tensile cracking, concrete compressive strength degradation was implemented and the tensile capacity of concrete maintained by the reinforcing steel (tension-stiffening effect) is considered. Using the concept of average stresses and strains, a criterion is proposed to simulate the tension-stiffening effect based on the force equilibriums, compatibility conditions, and bond stress-slip relationship between reinforcement and the surrounding concrete. The finite element model predictions are validated by comparison with available experimental data. In addition, correlation studies between analytical results and experimental values from idealized shear panel tests were conducted. Load-displacement relations of shear panel beams and walls under various stress conditions are then evaluated to verify the soundness of the proposed model. (C) 2001 Elsevier Science Ltd. All rights reserved.The research reported in this paper was made possible
by the ®nancial supports from the National Research
Laboratory funded by the Ministry of Science and
Technology of Korea and BK21 project funded by the
Ministry of Education of Korea. The authors would like
to express their gratitude to both organizations for their
support
Cracking behavior of RC panels subject to biaxial tensile stresses
No full textAn analytical model which can Simulate the post-cracking nonlinear behavior of reinforced concrete (RC) members such as bars and panels subject to uniaxial and biaxial tensile stresses is presented. The proposed model includes the description of biaxial failure criteria of concrete in the tension-tension region and the average stress-strain relation of reinforcing steel. Based oil strain distribution functions of steel and concrete after cracking, a criterion to consider the tension-stiffening effect is proposed using the concept of average stresses and strains. The validity of the introduced model is established by comparing the analytical predictions for reinforced concrete uniaxial tension members with results from experimental Studies. In advance, correlation Studies between analytical results and experimental data are also extended to RC panels Subject to biaxial tensile stresses to verify the efficiency of the proposed model and to identify the significance of various effects oil the response of biaxially loaded reinforced concrete panels. (c) 2005 Elsevier Ltd. All rights reserved.The research reported in this paper was made possible by
the financial support from the Smart Infra-Structure Technology
Center funded by the Korea Science and Engineering
Foundation. The authors would like to express their
gratitude to this organization for the financial support
FE analysis of RC shear walls subject to cyclic loading
No full textThis paper describes an extension of a numerical model that was developed to simulate the non-linear behaviour of reinforced concrete (RC) structures subject to monotonic in-plane shear, and introduced in the companion paper. The extended model is intended to effectively simulate the behaviour of RC structures under cyclic loadings. While maintaining all the basic assumptions adopted in defining the constitutive relations of concrete under monotonic loading, a hysteretic stress-strain relation of concrete, which crosses the tension-compression region, is defined. In addition, unlike previous simplified hysteretic stress-strain relations, curved unloading and reloading branches inferred from the stress-strain relation of steel considering the Bauschinger effect are used. Modifications of the stress-strain relation of concrete and steel are also introduced to reflect a pinching effect depending on the shear span ratio, and to represent an average stress distribution in a cracked RC element, respectively. Finally, correlation studies between analytical results and experimental studies are conducted to establish the validity of the proposed model.The research reported in this paper was made possible
by financial support from the Smart Infra-Structure
Technology Center funded by the Korea Science and
Engineering Foundation. The authors would like to express
their gratitude to this organisation for the financial
support
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