Design criteria for haunched rigid frames

Abstract

The photoelaetic technique is applied to evaluate two methoda of design for single span, haunched rigid frames. A plastic model of a haunched rigid frame is uniformly loaded, and observed under polarized light. Photographs of the stress pattern in the frame are used to evaluate the boundary stresses. Analytical solutions for the boundary stresses are made: using the distance between column center lines as the effective span; using the clear span between columns as the effective span. A comparison is made between the analytical solutions and the photoelastic evaluation. The use of center line distance between columns as the effective span is found to be safe in all frames tested. However, the use of clear span as effective span provides an unconservative estimate in the case of deep, wide haunches.