Active Researches

Nonlinear response of shear wall structures under wind loads

This study aims to examine the potential over-strength and ductility implicit in mid- to high-rise reinforced concrete shear walls designed to remain essentially elastic when subjected to rare wind loads by taking advantage from knowledge available in earthquake-resistant design. A set of 10 to 25 story reinforced concrete shear walls part of multi-story office building located in Montreal, Canada is selected and designed under the design wind loads, which governs the lateral load-resisting system of the building, in accordance with National Building Code of Canada. Three wall configurations including rectangular, barbell and flanged are chosen. Fiber-based numerical model of the walls are then developed in Perform 3D and used to perform the nonlinear static (pushover) analysis to evaluate the lateral nonlinear behavior of the walls under gravity loads and the lateral displacement corresponding to wind serviceability limits as defined in Prestandard for Performance-Based Wind Design (ASCE). Ductility and over-strength of the structures are obtained using the results of the pushover analyses. The results confirmed moderate nonlinear capacity under extreme wind loads with little damage at the base of the wall as the source of nonlinear response. The results indicate that the limited nonlinear response observed in the reinforced concrete shear walls can potentially be leveraged to economize the design of such systems under wind loads.

Stochastic analysis of reinforced concrete structures

In this study, the effect of material and geometric uncertainties on the response of a well-designed RC frame is evaluated. In addition to the inherent variability of parameters, spatial variations of the parameters in the structure are also considered assuming a story-based construction sequence. A probabilistic analysis framework is developed which links a MATLAB code with stochastic analysis capabilities to a nonlinear finite element (FE) analysis program capable of capturing both flexural and shear damage modes in RC frames. The random input parameters for the FE model are generated using the JCSS probabilistic models and the Latin Hypercube Sampling technique both implemented in the MATLAB code. The results of deterministic and stochastic pushover analyses are presented to assess the influence of the uncertain parameters on the global and local behavior of the RC frame structure. The analysis results are discussed in terms of base shear capacity, ductility, soft/weak story, and plastic hinge formation.

Cyclic response of cold-formed steel shear walls with boundary elements

In this study, a new finite element model is developed to simulate lateral behavior and complete hysteresis response of steel sheathed CFS shear walls. LS-DYNA software, which is an advanced general-purpose nonlinear finite element program and can simulate and predict complex real-world problems, is used to simulate the CFS shear walls. The proposed model is validated against available test data under monotonic loading. The validated model can be used for the new design and performance assessment of CFS shear walls.

Macro modeling of SC shear walls

This research  presents a new fiber-based macro model for nonlinear simulation of steel-concrete walls by taking advantage of existing reinforced concrete and steel plate shear wall models . The proposed macro model can efficiently reproduce the nonlinear cyclic response of steel-concrete walls with reduced computational efforts compared to continuum finite element model counterparts, which can be used in the seismic analysis of existing and new building structures consisting of steel-concrete walls.

Macro Modeling of RC shear walls

This study presents an overview of available macro models for RC shear walls in the literature. Then, the accuracy of models in predicting the cyclic response of RC shear walls with a wide range of design variables is investigated using a comprehensive test database. The design variables considered in the study include level of axial force, presence of boundary elements, wall aspect ratio, and reinforcement ratio. Based on the analysis results, the discrepancies between different macro models, as well as their accuracy to simulate the cyclic response of RC walls and capture the failure mode, are compared and discussed. The analysis results provide a useful guideline to help researchers and engineers to select the most suitable modelling approaches within their design parameters and providing the most accurate result with less computational effort.

Numerical and experimental study on the tensile capacity of single and group of adhesive bonded anchors 

In this study, the effects of steel reinforcement, embedment depth, and proximity to the free edges of RC components are studied using a set of 36 experiments and comprehensive analyses in 1, 4, and 6 anchor formations. The tensile capacities observed in the tests are compared against ACI 318 predictions. The main effects of parameters, as well as their interactions, are analyzed and discussed. Based on the results of this experimental program, several recommendations for the installation of adhesive bonded anchors in narrow concrete components are provided.