# Experimental Study of High-Strength Concrete-Steel Plate Composite Shear Walls
## 2 Experimental Investigation  
### Specim Properties  
Two batches of specimens were designed, constructed, and tested under quasi-static cyclic loadings, including RCSW and RCPSW. Table 1 lists key information for test specimen configurations. Specifically, the specimens in Batch No.1 (RCSW 1-X and RCPSPSW 1-X) with the aspect ratio (height/width, \(h/b\)) of 1.5 were designed to study the shear behavior, while the specimens in Batch No.2 (RCSW 2-X and RCPSPSW 2-X) with a higher aspect ratio (2.7) were mainly designed for the flexure behavior investigation. These two aspect ratios were selected based on available references [1; 8; 9; 10; 14; 19; 32; 33; 34; 1; 35] and past engineering experience in high-rise building design to purposely achieve shear failure mode and flexure failure mode, respectively. Apart from the aspect ratio, the vertical axial load is another critical parameter that affects the seismic performance of shear wall specimens. As listed in Table 1, a wide range of vertical load values were applied on shear specimens (900-1500 kN) and flexure specimens (2180-3050 kN) in the quasi-static test to simulate different levels of axial loads that would be expected in the design of high-rise buildings. An axial compression ratio, \(n\), is defined as the ratio of the applied vertical load to the compression capacity of the wall section and it is given by  
\[n=\frac{N}{f_{\mathrm{c}}A_{\mathrm{c}}+f_{\mathrm{ay}}A_{\mathrm{a}}+f_{ \mathrm{py}}A_{\mathrm{p}}} \tag{1}\]  
where \(N\) represents the vertical load that is applied by the hydraulic jack,\(f_{\mathrm{c}}\) is the compressive strength of concrete, \(f_{\mathrm{ay}}\) and \(f_{\mathrm{py}}\) are yielding strength values of I-shape steel profiles and steel plate, and \(A_{\mathrm{c}}\), \(A_{\mathrm{a}}\), and \(A_{\mathrm{p}}\) indicate the area of concrete section, boundary I-shaped steels, and embedded steel plate. For given vertical loads, axial compression ratio ranges from 0.33 to 0.50 for shear specimens and 0.42 to 0.70 for flexure specimens. Note that these values are relatively high for shear walls in building structures, and very few past research work has been performed while using such high axial compression ratios. Figure 2 shows the cross-sectional dimensions and reinforcing detailing for RCSW and RCPSPSW. All of the specimens were designed with the target concrete cubic compressive strength of \(f^{\prime}_{\mathrm{c,cube}}=80\) MPa. The use of high-strength concrete not only effectively increases the lateral capacity, but it also significantly reduces the required wall thickness due to code-specified axial compression ratio limits in the design of tall buildings [3; 4]. The geometrical sizes and steel reinforcement were carefully designed, so that desirable failure mechanisms would take place in the test for different batches of specimens. For instance, longitudinal boundary reinforcements with relatively smaller diameters (\(\varphi 8\) and \(\varphi 10\)) were purposely implemented in specimens with the aspect ratio of 2.7, so as to observe a flexure mode of failure prior to achieving a shear mode of failure. The geometric dimensions and reinforcement arrangement were identical for RCSW and RCPSPSW specimens with specified aspect ratios. The shear specimens consist of an 800 mm wide by 80 mm thick wall web and two 100 mm wide by 120 mm thick boundary elements. As for flexure specimens, the thickness values for the web and boundary elements are 150 mm and 190 mm, respectively. The distances that were measured from the top surface of the footing to the lateral loading point are 1.2 m and 2.16 m for shear and flexure specimens, as shown in Figure 2. For the RCPSPSW specimens, I-shaped steels in boundary elements were welded to the 5 mm thick steel plate that was embedded in the wall web, and steel studs or tie bars were used to ensure the bonding strength between the concrete and steel plate.