Models for Evaluating Shear Strength on Members with Circular Cross Section

Solid circular columns are often used as structural supports in bridges, buildings and foundations due to their simplicity of construction and because their strength is similar in any direction. This deem them very suitable to resist wind and seismic loads. Hollow core circular concrete members are much less structurally used than solid circular cross sections. However, these can be found in concrete chimneys, concrete pipes and elevated water tanks, as well as in large bridge columns and offshore platforms. Codes do not usually propose specific formulations for evaluating the shear strength of such structural types or if they do, they do so in a very simplified manner.

Hence, an analytical model for evaluating the contribution of the transverse reinforcement in concrete members of solid and hollow circular cross section is presented in this paper. After a thorough bibliographic research on the previous studies on the matter, the shortage of work accomplished on the topic has been assessed and the unsolved problems identified. A formula for evaluating the shear transferred by spiral reinforcement in solid members is presented. A formula for the calculation of hollow core circular columns with both vertical and spiral reinforcement is also deduced. Assumptions made for the calculation of this formulation have been deduced theoretically and then checked empirically. Hence, shear tests on circular hollow core specimens will be also presented.