This study is concerned with the behaviour of single span slender reinforced concrete members with depth/span ratios equal to and larger than 1. A series-of deep panels with depth/span ratios between I and 4 was studied experimentally. These elements were tested under third point loads at the top level. Aspects such as stress development, in-plane and out-of-plane deformations, cracks and modes of failures were thoroughly investigated. Experimental stresses are compared with solutions given by the Finite Element technique. It is shown that the shear strength of deep panels increases for depth/span ratios beyond unity, in disagreement with present design recommendations.
A second group of walls was tested under five different combinations of uniformly distributed top and bottom vertical in-plane loads. A range of percentages of vertical web reinforcement was used. The quantity of reinforcement showed no effect in retarding the formation of horizontal
cracks but their widths were progressively reduced.
The effect of soffit load on crack formation and failure of
these walls is analysed. Test results are compared with current design recommendations. Soffit load causes tensile cracking of the concrete to occur earlier than under top loads only. It also reduces the bearing strength of the specimens.
Crushing of the bearing zone was the commonest mode of failure. This problem is studied and a general introduction to its understanding is presented.
Reinforced concrete deep members, when cast in their vertical position, present problems of segregation, which cause a variable quality of concrete within the depth. A large difference in the strength of concrete (up to 40 per cent) was observed between the upper and lower levels in specimens 1m deep. Some attention is given to this problem, in order to analyse more accurately the experimental results.