In fact, the SPrc units experienced the GW786034 smallest percentage increase in capacity from low steel content to high steel content. No more increase in shear strength could be observed when the steel content was increased from moderate to high. Moreover, all the SPrc units with thick steel plates of tp = 36mm could not develop their full capacities, and the problem is likely caused by insufficient wall reinforcement and will be discussed in Section 3.4.Table 2Calculated strength and stiffness for the prototype coupling beams.The increase in capacity with the increase in steel content in the MPrc units was not as significant as in the LPrc units, but the former were the most effective under high steel content. However, the capacity was increased at a cost of decreased ductility in the MPrc units as the strength dropped rapidly after reaching the peak in Unit MPrc-0.

5c3 with high steel content (see Figure 9(c)). The MPrc units (with span-to-depth ratio of 2) appear to be the most effective PRC coupling beams in terms of enhancement of strength under various steel ratios.3.3. Effects of Anchorage Length of Steel Plate in Wall PierThe anchorage length effect can be investigated by comparing the strengths and stiffness of models with identical beam geometry and beam steel ratios but different anchorage lengths (i.e., models in the same series of each group). The anchorage length could slightly affect the strength and stiffness of a PRC coupling beam, but the effect would diminish beyond the minimum required anchorage length for full capacity development.

This explains why when the anchorage lengths in the MPrc units and the LPrc units were increased from 0.5l to 0.75l and from 0.375l to 0.5l, respectively, both the stiffness and the peak loads only increased insignificantly. This was in contrast with the cases when the La values were increased from 0.335l to 0.5l and 0.25l to 0.375l, respectively. The stiffness remained almost the same in the SPrc units for all the three anchorage lengths. This, on the one hand, suggests that an anchorage length of 0.5l may be good enough for the SPrc units and, on the other hand, suggests that the stiffness may be mainly determined by the beam geometry, and the role of the anchorage length diminishes as the span-to-depth ratio decreases.The beam strengths increased with the anchorage length with a decreasing rate in all the SPrc and the LPrc units.

Depending on the longitudinal steel ratio and the plate thickness, doubling the anchorage lengths in the SPrc and the LPrc units could cause an increase in strength ranging from 2 to 10%.The response of the MPrc units was more sensitive to the change in Anacetrapib anchorage length, and the strength increased more significantly with the increasing anchorage length in this group.