Crack Width Evaluation of Reinforced Concrete Membrane Elements

The design methods developed over the last few decades to describe the behaviour of two-dimensional reinforced concrete elements subjected to in-plane loading do not permit a simplified assessment of crack opening: some of these methods, in fact, permit this assessment but are difficult to use for practical design purposes, whereas others, instead, can only be used to assess the ultimate strength of a structure. This paper proposes a method for the evaluation of crack opening on the basis of generalisable assumptions regarding the behaviour of the materials at the crack. By adopting a few simplifications, that are definitely acceptable for design purposes under serviceability loads, the proposed method leads to a closed form relationship that permits an immediate evaluation of crack opening. A comparison between the results supplied by the model and the results obtained from a testing campaign performed at the laboratories of the University of Houston makes it possible to appreciate the validity of this approach.