Shear design of large footings

Experimental and analytical research has been conducted in order to improve the knowledge of one-way shear behaviour of large reinforced concrete footings that are supported on soil.;A total of 13 large and 4 small footing type specimens were tested under combinations of concentrated loads and uniformly distributed loads to represent column loads and the uniformly distributed soil pressure. Five of these specimens were subjected to indirect loading where the column load introduces tension into the footing. A number of specimens were tested such that only a portion of the footing is subjected to uniformly distributed loads in order to simulate non-uniform soil pressure distribution under footings.;The experimental results show that in most cases the shear capacity of the footings was considerably greater than that predicted by the current concrete codes. The results also indicate that there is a significant size effect that influences the shear strength of large footings. It was found that the difference in shear capacity between indirect loading and direct loading is much smaller than that suggested by current design codes. It was observed that the shear stress at failure can noticeably decrease if the soil pressure concentrates towards the ends of the footing.;In this thesis, the applicability of sectional models is expanded in order to predict the shear strength of members with disturbed regions such as footings and deep beams. Simple expressions for the transverse clamping stresses that are introduced to these members are developed and incorporated into a non-linear sectional analysis program, Response-2000. It is shown that by accounting for the transverse clamping stresses in the solution procedure, sectional models can be utilized to predict the shear strength of such members.;Program "Response-2000 with clamping" is verified against a number of experiments from the literature. This has shown that sectional models that consider the beneficial effects of transverse clamping stresses, give reasonably accurate shear strength predictions for members with disturbed regions such as footings and deep beams.;Recommendations for changes to existing code provisions on shear design of footings are given based on the results of the experimental and analytical research.