Academic literature on the topic 'RC and masonry'

The concrete shear walls of masonry structures with an RC frame on the first story are low-rise shear walls with a height–width ratio of less than 1. The strength, stiffness, and ductility of these low-rise shear walls are not matched, resulting in poor seismic performance. Based on the idea of the passive control theory and multi-seismic defensive lines, the scheme of a masonry structure with an RC frame on the first story with a concrete-filled steel tubular (CFST) damper is proposed in this paper. To explore the seismic mitigation effect of a CFST damper applied to a masonry structure with an RC frame on the first story, the seismic performance under low-reversed cyclic loading of the frame with the CFST damper is first compared with that of the energy-dissipated low-rise concrete shear wall proposed by previous researchers and the ordinary low-rise concrete shear wall. Furthermore, the response of the masonry structure model with an RC frame on the first story with a CFST damper and two other comparative structural models under earthquake action are discussed. The results show that a masonry structure with an RC frame on the first story with a CFST damper has a fuller hysteretic loop, lighter pinching, better energy dissipation ability, and better seismic performance. Compared with the other two structures, the energy dissipation capacity of the masonry structure with an RC frame on the first story with a CFST damper is significantly improved, by 1.25~1.5 times. The amplification effect of the deformation angle allows the CFST damper to play a significant role in energy dissipation, whereas the main structure still undergoes a small deformation. The CFST damper can dissipate more seismic energy to protect the main structure from damage and improve the seismic performance of masonry structures with an RC frame on the first story.

Assembly technology using prefabricated reinforced concrete (RC) members can effectively improve the seismic performance of existing masonry buildings. In this study, an existing masonry wall is enhanced by two pieces of prefabricated RC panels bonded on both surfaces of the wall. In order to guarantee the co-action between RC panels and the masonry wall, three techniques are employed, specifically, RC dowelling keys, grouting agent, and post-cast concrete bands. To investigate the interaction and force transmission between the two components, this study builds sophisticated finite element models and conducts nonlinear analyses to simulate the quasi-static cyclic tests. It is demonstrated that the proposed retrofitting technology effectively improves the seismic performance of existing masonry walls. The strength of existing walls increases 3-4 times and the stiffness increases 2-3 times, so that the requirement of current seismic design code is satisfied.

Reinforced concrete (RC) frame buildings with masonry infills represent one of the most common structural typologies worldwide. Although, in the past, masonry infills were frequently considered as non-structural elements and their interaction with the structure was neglected, earthquakes occurring over the last decades have demonstrated the important role of these elements in the seismic response of all RC-infilled building typologies. In this regard, the selection of the most suitable numerical modelling approaches to reproduce the hysteretic response of the masonry infills—and their interaction with the RC frames—is still an open issue. To deal with this issue, in this study, a macro-classification based on different available databases of experimental tests on infilled RC frames, is firstly proposed to understand the variability in the infill properties and the corresponding numerical modelling uncertainties. Five masonry infill types are selected as representative for the typical existing configurations in Italy and other Mediterranean countries. Three of those masonry infill types are then selected to carry out a more detailed analysis, namely their numerical modelling validation using experimental testing results, considering and comparing the main formulations available in the literature for the definition of the hysteretic behaviour of infills. From such a comparison, the model that minimizes the prediction error, according to specific features of the selected masonry infill, is identified for each masonry infill type.

Masonry infilled RC frames are one of the most common structural forms, the damage of which, in earthquake events, usually cause serious losses. The determination of the seismic performance target is the key foundation of performance-based seismic evaluation and design for masonry infilled RC frames. In this paper, an extensive database of experimental tests on infilled RC frames loaded in an in-plane direction is collated. According to the crack propagation and elastic-plastic characteristics of infilled RC frames, the damage process is divided into four stages, and then the criteria of the damage states (DS) are proposed. In addition, the seismic performance targets expressed as inter-story drift ratio (IDR) for the four stages are suggested, which would support the performance-based in-plane seismic analysis of infilled RC frames. Finally, the proposed in-plane seismic performance target is utilized to analyze the fragility of two masonry infilled RC frame structures.