Experimental evaluation of the interaction between strength concrete block walls under vertical loads

Abstract

This paper aims to evaluate the interaction between structural masonry walls made of high performance concrete blocks, under vertical loads. Two H-shaped flanged wall series, all full scale and using direct bond, have been analyzed experimentally. In one series, three flanged-walls were built with the central wall (web) supported and, in the other one, three specimens were built without any support at the central web. The load was applied on the central wall and vertical displacements were measured by means of displacement transducers located at eighteen points in the wall-assemblages. The results showed that the estimated load values for the flanges were close to those supported by the walls without central support, where 100% of the load transfer to the flanges occur. The average transfer load rate calculated based on the deformation ratio in the upper and lower section of the flanged-walls, with the central web support, were 37.65% and 77.30%, respectively, showing that there is load transfer from the central wall (web) toward the flanges, particularly in the lower part of the flanged walls. Thus, there is indication that the distribution of vertical loads may be considered for projects of buildings for service load, such as in the method of isolated walls group. For estimation of the failure load, the method that considers the walls acting independently showed better results, due to the fact that failure started at the top of the central wall, where there is no effect of load distribution from the adjacent walls.

Joints in masonry walls

“…In the models without the cooperating slab, the walls failed in the upper part close to the location of the load (Figure 3a) and along the whole height when the RC slab was introduced (Figure 3b). In the tests presented by Castro et al [7], performed on the H-shaped models of the walls, investigation was made of the influence of the type of wall joint. The tests covered the elements without a bond and with a full masonry bond, made of hollow concrete blocks.…”

“…However, in this case, the effectiveness of innovative clamp anchors (carbon rods wrapped vertically and spirally with invar steel mats) was evaluated. The performed tests F I G U R E 3 Patterns of failure cracking of test specimens: (a) vertically loaded slender walls without RC slab [6], (b) vertically loaded slender walls with RC slab [6], (c) flanged walls with full joints [7], and (d) flanged walls without full joints [7] showed high effectiveness of both types of joints. Application of the innovative connector made of carbon fiber almost doubled the magnitude of the load, causing cracks in the joint with respect to the joint without connectors and without the masonry bond.…”

Joints in masonry walls

“…When an RC slab was cast in the upper part the joints failed along the whole height. The tests Castro, Alvarenga and Silva (2016) were focused on the influence of the type of joint. The H-shaped models were made of concrete masonry units with hollow cores.…”

Testing Joints between Walls Made of AAC Masonry Units

“…The relationship between the type of bond between intersecting walls and the load-bearing capacity of test models was investigated by Castro et al [1]. The models with no bond and with traditional masonry bond were tested.…”