Shear fatigue strength of reinforced concrete members without transverse reinforcement according to the compression chord capacity model

摘要

Although the shear fatigue behaviour of elements without shear reinforcement has been studied for a while, there is still a need for a simple mechanical model that evaluates the shear fatigue strength. The Compression Chord Capacity Model (CCCM), previously developed by the authors, is a simplified model for the shear strength prediction of reinforced and prestressed concrete members with and without transverse reinforcement, with I, T or rectangular cross-sections. This model represents a useful tool for structural design and assessment in engineering practice. In this paper, the CCCM has been extended to assess the fatigue shear strength of RC elements. This extension is consistent since the existing observed fatigue failure modes show similarities with the initial assumption of the model, which considers that the member shear strength is controlled by the shear capacity of the flexural compression chord. Three different approaches to take into account the influence of the fatigue have been combined with the CCCM. In general, a good performance of the model combined with the three different approaches was observed when analysing the ratio V-test/V-pred through a database of 87 tests previously published by other authors, showing a low scatter ( 15%) and a significant safety given by the minimum ratio and the 5th percentile.