shows the cracking development of each specimen corresponding to the early loading stage, peak load and failure respectively. For specimen S-1, the first cracking loads Pcr were 180 kN and −160 kN in the positive and negative directions. The cracks were firstly observed at boundary elements and then extended toward the web region (Fig. 5(a)). Then the outermost longitudinal reinforcing bars of the boundary elements yielded at the lateral displacement of 2.7 mm. As the lateral displacement was increased, more inclined cracks were developed along the height of the wall boundary elements, and propagated toward the bottom web region with angles of roughly 45°degrees. The chord member and web brace of the embedded truss started to yield before the lateral displacement of 5.7 mm, since the corresponding strains were 3.025 × 10−3 and 2.998 × 10−3 respectively. The diagonal cracks became more and more concentrated at the web region (Fig. 5(b)). At the end of testing, the wall panel was almost separated into two parts by the diagonal cracks. Severe concrete spalling off on the web region was observed (Fig. 5(c)). The distributed reinforcements were exposed and buckled at failure