# Experimental Study of High-Strength Concrete-Steel Plate Composite Shear Walls
## 5 Summary and Conclusions  
This paper introduces a high-strength reinforced concrete-steel plate composite shear wall system as lateral load resisting elements the design of high-rise building structures. A total of 11 RCSW and RCSPSW specimens were tested under quasi-static cyclic lateral loading to investigate the effects of critical factors on their seismic performances, including embedment of steel plate, aspect ratio, axial compression ratio, etc. Throughout the test procedure, the progression of damage and failure modes were observed and the key parameters were determined, such as lateral load capacity, ultimate displacement, ductility factor, and EVD coefficient. In addition, the design models were suggested to determine the shear and flexure strength of RCSPSW. By analyzing the data collected from experimental tests, the following conclusions are drawn. 1. Shear and flexure modes of failure dominate in specimens with the aspect ratio of 1.5 and 2.7, respectively. Inclined cracks were observed on the shear specimens, whilst flexure-tension cracks and flexure-shear cracks were mainly distributed in the lower half of boundary elements and wall web in flexure specimens. As compared to the RCSW specimens, more densely-distributed,  
Figure 19: Flexure Design Models Developed based on Plane Section Assumption. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Specimen No.**} & \multicolumn{2}{c}{**Experimental Results (kN)**} & \multicolumn{2}{c}{**Design Model**} & \multicolumn{3}{c}{**Differences**} \\ \cline{2-7}  & **Positive** & **Negative** & **Average** & **Results (kN)** & **Positive** & **Negative** & **Average** \\ \hline RCSW 2-1 & 469 & 514 & 492 & 341 & 27\% & 34\% & 30\% \\ \hline RCSW 2-2 & 540 & 536 & 538 & 389 & 28\% & 27\% & 28\% \\ \hline RCSW 2-3 & 570 & 578 & 574 & 481 & 16\% & 17\% & 16\% \\ \hline RCSPSW 2-1 & 581 & 697 & 639 & 387 & 33\% & 44\% & 39\% \\ \hline RCSPSW 2-2 & 646 & 674 & 660 & 434 & 33\% & 36\% & 34\% \\ \hline RCSPSW 2-3 & 674 & 701 & 688 & 512 & 24\% & 27\% & 25\% \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Comparisons of Experimental and Design Strength Capacities for Flexure Specimens. but finer, cracks took place in the RCPSSW specimens. With the increase of axial compressive loads, the crack quantity becomes less and the crack width is smaller due to the compaction of compression forces. 2. Obvious pinching\" effects were observed in hysteresis loops of RCSW specimens. With the embedment of the steel plate, hysteresis curves appear in a plumper shape with higher peak lateral load capacities, but a severer post-peak strength and stiffness degradation. 3. RCPSSW system demonstrates superior lateral load capacities over RCSW, in general. The RCPSSW shear specimens show acceptable deformability for design purpose with the ultimate drift value of 1.0%. As for RCPSSW flexure specimens, the ultimate drift is larger than 1.0% and the ductility factor is around 4 when the axial compression ratio is lower than 0.50. 4. Axial compression ratio has an indispensable effect on the lateral load performance of wall specimens. In general, the peak lateral load increases, but ultimate displacement decreases as the axial compression ratio increases. A severer strength and stiffness degradation was observed for RCPSPSW flexure specimens with the axial compression ratio higher than 0.50. When the axial compression ratio increases to 0.58, the ductility factor substantially decreased to 2.61 and the ultimate drift is lower than 1.0%. 5. The brittleness of high-strength concrete explains the relatively lower deformability of the RCPSSW specimens under high axial compression ratios. Another possibility is the weak concrete confinement effect on the embedded steel plate due to the small wall thickness values of the test specimens. The steel plate tends to buckle when severe concrete spalling occurs under higher axial compressive loads, causing substantial strength and stiffness degradation. 6.