Ultimate Strength of Parabolic Concrete Arches

This investigation is aimed to present a simple analytical approach for predicting the ultimate strength of concrete arch using theory of plasticity. Six models of two-hinged parabolic concrete arches with and without steel reinforcement were tested under concentrated load. The observed behavior of cracking strength and collapse load of the arches tested were compared with those predicted by the analytical procedure proposed here. The arches tested were un-reinforced concrete, lightly reinforced concrete, and concrete with filing iron respectively. A Good agreement is found between the proposed analysis and test results. Tests have shown that the collapse of all arches was mainly due to the formation of two plastic hinges at a point of maximum bending moment which is similar to collapse mechanism adopted in this study. The use of light concentric steel reinforcement resulted into a significant increase in the ultimate load. This increase reaches up to three times of that without reinforcement. Ductility was also found to be greatly improved due to using steel reinforcement in arches. The procedure of analysis in this paper can give a simple guide for design of concrete arch.