Effect of Masonry Infill Panels on the Seismic Response of Reinforced Concrete Frame Structures

The present work concerns the numerical investigation of reinforced concrete frame buildings containing masonry infill panel under seismic loading that are widely used even in high seismicity areas. In seismic zones, these frames with masonry infill panels are generally considered as higher earthquake risk buildings. As a result there is a growing need to evaluate their level of seismic performance. The numerical modelling of infilled frames structures is a complex task, as they exhibit highly nonlinear inelastic behaviour, due to the interaction of the masonry infill panel and the surrounding frame. The available modelling approaches for masonry infill can be grouped into two principal types; Micro models and Macro models. A two dimensional model of the structure is used to carry out non-linear static analysis. Beams and columns are modelled as non-linear with lumped plasticity where the hinges are concentrated at both ends of the beams and the columns. This study is based on structures with design and detailing characteristics typical of Algerian construction model. In this regard, a non-linear pushover analysis has been conducted on three considered structures, of two, four and eight stories. Each structure is analysed as a bare frame and with two different infill configurations (totally infilled, and partially infilled). The main results that can be obtained from a pushover analysis are the capacity curves and the distribution of plastic hinges in structures. The addition of infill walls results in an increase in both the rigidity and strength of the structures. The results indicate that the presence of non-structural masonry infills can significantly modify the seismic response of reinforced concrete "frames". The initial rigidity and strength of the fully filled frame are considerably improved and the patterns of the hinges are influenced by structural elements type depending on the dynamic characteristics of the structures. Doi: 10.28991/cej-2021-03091764 Full Text: PDF

Irregularity of the Distribution of Masonry Infill Panels and Its Effect on the Seismic Collapse of Reinforced Concrete Buildings

On 16 April 2016, an earthquake of Mw 7.8 shook the coast of Ecuador, causing the destruction of buildings and a significant number of casualties. Following a visit by the authors to the city of Portoviejo during the debris removal and recovery stage, it was noted that several reinforced concrete buildings located on corners had collapsed in the central part of the city. These buildings were characterized by the presence of masonry at the edges of the buildings but not between the two mostly open-plan facades on the corner for practical reasons. This article reviews the effect of masonry infill panels on the seismic response of reinforced concrete structures. For this, a model that contains the geometric and mechanical characteristics typical of collapsed buildings was generated and subjected to nonlinear analysis, with both static and dynamic increments. The results show the clear influence of the masonry infill panels on the structural response through the torsional behavior that is reflected in the evolution of the floor rotations. Finally, dynamic incremental analysis is used to obtain the collapse fragility curve of the building, and a new damage measure based on floor rotations is proposed.

Experimental/Numerical Evaluation of Steel Trapezoidal Corrugated Infill Panels with an Opening

This paper investigates the influence of an opening in the infill steel plate on the behavior of steel trapezoidal corrugated infill panels. Two specimens of steel trapezoidal corrugated shear walls were constructed and tested under cyclic loading. One specimen had a single rectangular opening, while the other one had two rectangular openings. In addition, the percentage of opening in both specimens was 18%. The initial stiffness, ultimate strength, ductility ratio and energy dissipation capacity of the two tested specimens are compared to a specimen without opening. The experimental results indicate that the existence of an opening has the greatest effect on the initial stiffness of the corrugated steel infill panels. In addition, the experimental results reveal that the structural performance of the specimen with two openings is improved in some areas compared to the specimen with one opening. To that end, the energy dissipation capacity of the specimen with two openings is obtained larger than the specimen with one opening. Furthermore, a number of numerical analyses were performed. The numerical results show that with increasing the thickness of the infill plate or using stiffeners around the opening, the ultimate strength of a corrugated steel infill panel with an opening can be equal to or even more than the ultimate strength of that panel without an opening.

Seismic Evaluation of New Steel Infill Panels for Steel Shear Walls

Corrugated Steel Shear Wall (CSSW) is an efficient shear wall system, which has higher energy dissipation capacity, ductility and stiffness when compared to the Steel Plate Shear Wall (SPSW) with flat infill plate. Despite of these advantages, the ultimate load of CSSW is lower than that of SPSW. Various studies conducted to improve the cyclic behavior of CSSW revealed that increasing corrugation angle might enhance energy dissipation capacity and toughness of CSSWs. However, the ultimate load of CSSW was not improved by increasing the corrugation angle. Thus, the current study proposed new corrugated infill panel schemes to improve the ultimate load of CSSWs. To this end, Finite Element (FE) models were established using ABAQUS/Standard and verified with the experimental results from previous researches. The corrugation angle of the proposed plates was found based on a numerical investigation on seven CSSW FE models with the corrugation angle ranges from 30° to 120°. The FE results revealed that the model with the corrugation angle of 120 achieved highest ultimate load, energy dissipation capacity and toughness amongst the CSSW models. In addition, the ultimate loads, energy dissipation capacities and toughness of the proposed infill plates were up to 11.8%, 53.9% and 8.8% respectively higher than those of CSSW model with the corrugation angle of 120°. Furthermore, the proposed infill plates use up to 13.4% lower amount of steel compared to the corrugated plate with the corrugation angle of 120. Doi: 10.28991/cej-2021-03091678 Full Text: PDF