Optimization of concrete stiffeners for confined brick masonry structures

In order to ensure safety of confined brick masonry structures, researchers have recommended the use of reinforced-concrete (RC) stiffeners. Most of the time, the seismic demand is much less than the provided strength even with the use of minimum stiffeners cross-section, concrete strength and reinforcement re-bars. Thus, there is a need to correlate the seismic demand with the stiffeners design. In this paper, the optimization of RC stiffeners is proposed using a diagonal approach and validated numerically. The purpose of this effort is to ensure both structural safety and economy at the same time. A total of 50 macro-models of brick masonry structures are developed and analyzed in SAP2000 for different seismic parameters. The principle critical stress and top maximum displacement (in-plane) are studied in detail. The prediction of cracks propagation is also made. The behaviour of different confined brick masonry structures (CBMS) are compared with that of unconfined brick masonry structure (UBMS). As anticipated, CBMS (with proposed stiffeners) performed better compared to UBMS for respective seismic loadings. It is concluded that the proposed optimized stiffeners in CBMS meet the required seismic demand for combinations of seismic loadings.