Stress Analysis and a Method of Calculating the Normal Stress for Double-row Circular Web Opening Castellated Beamunder Pure Bending

Abstract

In order to fully use the exceptional qualities of the web of the high castellated beam,a new castellated steel beam member with double-row holesis proposed and the section normal stress calculation method is provided for serving as a guide for engineering applications and related studies of castellated beams with double-row holes. The numerical model of a double-row opening castellated beam was built and validated using the finite element program ABAQUS. The effect of opening rate and intermediate girder bridge height on the the normal stress distribution of the cross-section and the circumferential stress distribution around the hole of the castellated beam is investigated. The positive stress concentration coefficients are obtained by numerically fitting the finite element simulation results, and a simplified calculation method of positive stresses in the cross-section is proposed based on the ferrous truss method. On the central cross-section of the girder bridge,the largest positive stresses in the web occur at the connection between the flange and the web or at the edge of the opening near the flange. A near-zero stress region occurnear the neutral axis of the central section of the pier,and the normal stress of the rest is close to linear distribution. The maximum circumferential stress of the hole appears on the central section of the girder bridge,and the sign changes at φ of approximately 30°,150°,210°,and 330°. The opening rate of double-row opening castellated beams should not exceed 60%, and the ratio of bridge height to beam height in the middle of the double-row opening castellated beams should be kept between 1 / 12 and 1 / 6. In the above given range,the proposed simplified calculation approach for positive stresses has good accuracy.