Numerical modelling of RC strengthened columns under biaxial loading

Hugo Rodrigues,António Arêde,André Furtado,Humberto Varum

doi:10.1007/s41062-016-0008-9

Hugo Rodrigues, António Arêde + Show 2 more

Open Access

https://doi.org/10.1007/s41062-016-0008-9

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Abstract

During an earthquake, the reinforced concrete (RC) structures are subjected to deformations that may lead their structural elements to exceed the corresponding resistance limit state, forcing them to have nonlinear responses. The application of realistic numerical models that can represent the non-linearity of each structural element requires full examination and calibration. Furthermore, simplified numerical approaches that can represent the seismic behaviour of original and strengthened RC elements are of full importance. For this, the experimental tests are useful to calibrate the numerical models, and thus to capture as well as possible the real response of the elements. The main goal of this work is to evaluate the efficiency of a simplified numerical approach to represent strengthened RC columns with steel and CFRP jacketing, subjected to biaxial horizontal loading. The numerical modelling efficiency will be evaluated by comparing the numerical results with the experimental ones in terms of shear-drift hysteretic behaviour, initial stiffness and stiffness degradation, maximum strength and energy dissipation. The results shows a good performance of the numerical models, mainly for the RC columns strengthened with CFRP jacketing technique.

Highlights

The structural behaviour of reinforced concrete (RC) buildings when subjected to earthquakes should be regarded as a very important topic, as demonstrated in the earthquakes in Sichuan (China) in 2008 [1], L’Aquila (Italy) in 2009 [2], Port-au-Prince (Haiti) in 2010 [3] and Lorca (Spain) in 2011 [4] and more recently in Nepal
The numerical modelling efficiency was evaluated by comparing the numerical results with the experimental ones, in terms of: shear-drift hysteretic response, initial stiffness, stiffness degradation, maximum strength and energy dissipation
– Comparing the results between the RC columns of Group 1, it is possible to observe that the numerical models are better for the diagonal 458 load path

Summary

Introduction

The structural behaviour of reinforced concrete (RC) buildings when subjected to earthquakes should be regarded as a very important topic, as demonstrated in the earthquakes in Sichuan (China) in 2008 [1], L’Aquila (Italy) in 2009 [2], Port-au-Prince (Haiti) in 2010 [3] and Lorca (Spain) in 2011 [4] and more recently in Nepal. This is mainly justified by the reduced capacity to deform of the RC columns (reduced ductility) and the reduced amount of longitudinal reinforcement [6,7,8], which can be due to lower design seismic actions, use of plain rebars, poorer detailing, lap slices in critical regions, premature terminations of longitudinal reinforcement and lack of lateral confinement, which are common in existing structures built until late 1980s [9, 10]. Rodrigues concluded that: (i) initial column stiffness is not much affected by 2D load path; (ii) maximum strength in one specific column direction for each 2D test is always lower than that of the corresponding 1D test; (iii) ultimate ductility is clearly reduced in

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Conclusion