D. Liu - Senior Engineer, China Northwest Building Design Institute, Xi’an, P.R.China,
C. Yang - Senior Engineer, China Northwest Building Design Institute, Xi’an, P.R.China,

The hollow concrete blocks have been widely used to build the bearing walls of the multi-story buildings, especially in the region lack of clay soil. In order to increase the aseismic bearing capacity of the buildings, the reinforced concrete ring-beams are placed at the levels of each flooring and 5 to 7 vertical steel bars are inserted into the voids of the hollow concrete blocks at the intersections of the longitudinal walls and transverse walls. Then these vertical pockets are filled with concrete, cement mortar or grout. So that the structural edge elements have been created at the intersections of the walls. These vertical elements will confine all of the masonry walls and keep its from collapse while the buildings under the actions of the earthquake. For the medium-rise buildings, in addition to the ring beams and vertical reinforcements at the intersections of the walls, two or three horizontal steel bars are laid in the mortar of the masonry with the vertical interval of 0.4m, and one vertical steel bar is placed in the vertical pocket at the spacing of 0.4 ~ 0.6 m along all of the load bearing walls.