Yield-line analysis and experimental study of reinforced concrete slabs containing openings

Abstract

Four rectangular, isotropically reinforced concrete slabs were constructed and loaded until collapse. All slabs were fixed on three edges with the fourth edge free. Three slabs contained openings at various locations while the fourth remained solid. The magnitudes of deflections were measured during loading and the final yield pattern and ultimate load were compared to those predicted by simple and advanced yield-line theory. An analytical computer program was developed and is presented for quick evaluation of the ultimate load and collapse mode of many types of uniformly loaded slabs by simple yield-line theory. Short specialized programs were also formulated to analyze the experimental slabs, considering the presence of simple corner levers and edge loads around the openings. This resulted in more accurate theoretical predictions and produced estimates of the percent difference between simple and advanced theory predictions. Analysis of the results showed excellent agreement between the advanced theory predictions and the experimental results.