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Oguzmert M.,Saiful Bouquet Structural Engineers Inc. | Lui E.M.,Syracuse University
IES Journal Part A: Civil and Structural Engineering | Year: 2011

This article, which is the first of a two-part article, presents equations for computing equivalent linear system (ELS) parameters using a two-dimensional minimisation technique for estimating inelastic seismic demand of structures from elastic response spectra. Using two hysteretic models, the effects of initial damping, post-yield stiffness and degrading behaviour on the ELS parameters are investigated. The maximum inelastic response of structures modelled as single degree-of-freedom systems computed using the proposed method are compared with five other approximate methods as well as with results obtained using inelastic time-history analysis. It is observed that the proposed approach gives good results for structures that experience ductile behaviour with natural periods in the 0.3- to 3-s range. © 2011 The Institution of Engineers, Singapore. Source


Kolozvari K.,Saiful Bouquet Structural Engineers Inc. | Orakcal K.,Bogazici University | Wallace J.W.,University of California at Los Angeles
Journal of Structural Engineering (United States) | Year: 2015

Existing approaches used to model the lateral load versus deformation responses of reinforced concrete walls typically assume uncoupled axial/flexural and shear responses. A novel analytical model for RC walls that captures interaction between these responses for reversed-cyclic loading conditions is described. The proposed modeling approach incorporates RC panel behavior into a two-dimensional fiber-based macroscopic model. The coupling of axial and shear responses is achieved at the macrofiber (panel) level, which further allows coupling of flexural and shear responses at the model element level. The behavior of RC panel elements under generalized, in-plane, reversed-cyclic loading conditions is described with a constitutive fixed-strut-angle panel model formulation. The sensitivity of model results to various modeling parameters is investigated and results of the sensitivity studies are presented, whereas detailed information on calibration and validation of the proposed modeling approach is presented in a companion paper. © 2014 American Society of Civil Engineers. Source


Kolozvari K.,Saiful Bouquet Structural Engineers Inc. | Tran T.A.,University of California at Los Angeles | Orakcal K.,Bogazici University | Wallace J.W.,University of California at Los Angeles
NCEE 2014 - 10th U.S. National Conference on Earthquake Engineering: Frontiers of Earthquake Engineering | Year: 2014

Existing approaches used to model the lateral load versus deformation responses of reinforced concrete walls typically assume uncoupled axial/flexural and shear responses. A novel analytical model for RC walls that captures interaction between these responses under reversed-cyclic loading conditions is developed, calibrated and validated against detailed experimental data obtained from tests on five moderately-slender reinforced concrete wall specimens that have experienced significant levels of shear-flexure interaction. Response comparisons reveal that the analytical modeling approach captures the experimentally-measured nonlinear shear deformations as well as their coupling with flexural deformations throughout the cyclic loading history. In addition, the analytical results successfully represent various experimentally-measured responses, such as lateral-load versus wall-top-displacement relations, magnitudes and distributions of deformations associated with shear and flexure (global responses), as well as vertical strains (local response). Based on the comparisons presented, model capabilities are assessed and future model improvements are suggested. Source


Oguzmert M.,Saiful Bouquet Structural Engineers Inc. | Lui E.M.,Syracuse University
IES Journal Part A: Civil and Structural Engineering | Year: 2011

In this second part of the two-part article, the incorporation of a set of equivalent linear system parameters derived in the preceding article in a direct displacement-based design (DDBD) method is presented. By using the proposed design procedures for reinforced concrete and steel, 16 structures modelled as single degree-of-freedom systems are designed. Their responses are then compared with those obtained from a dynamic inelastic time-history analysis. The results show that the use of the proposed equations to calculate ζeq and Teq and the incorporation of the proposed DDBD procedures to proportion structures will produce reasonably good results with relatively simple computation effort. © 2011 The Institution of Engineers, Singapore. Source


Kolozvari K.,Saiful Bouquet Structural Engineers Inc. | Tran T.A.,University of California at Los Angeles | Orakcal K.,Bogazici University | Wallace J.W.,University of California at Los Angeles
Journal of Structural Engineering (United States) | Year: 2015

This paper presents the experimental calibration and validation of the analytical wall model that incorporates interaction between shear and flexural responses under cyclic loading conditions described in the companion paper. The model is calibrated and validated against detailed experimental data obtained from tests on five moderately slender reinforced concrete wall specimens that experienced significant levels of shear-flexure interaction. Test measurements were processed to allow for detailed comparisons between the predicted and measured wall responses at various locations and response levels. Response comparisons reveal that the proposed analytical model captures the experimentally measured nonlinear shear deformations and their coupling with flexural deformations throughout the cyclic loading history. In addition, the analytical results successfully represent various experimentally measured responses, such as lateral-load versus wall-top-displacement relations, magnitudes and distributions of deformations associated with shear and flexure, and local responses including flexural rotations, vertical strains, and concrete crack orientations. Based on the comparisons presented, model capabilities are assessed and future model improvements are suggested. © 2014 American Society of Civil Engineers. Source

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