Experimental Investigation of Retrofitted Web-Gap Regions in Steel Bridge Girders

Abstract

This paper describes an experimental study on retrofitting web-gap regions in steel girder bridges. The retrofit aims at reducing the stress concentrations at the intersection of connection plates and the web which can potentially be where distortion induced fatigue cracking initiates. In this study, a laboratory investigation was performed on a small-scale steel bridge bay under displacement-control vertical loading to simulate the differential deflection between two girders in actual bridges. A new method to retrofit the web-gap is proposed by modifying the existing slot-method by connecting the connection plate and web with steel angles on either side of the connection plate. The performance of the newly-developed retrofit technique, called the slot-angle technique, is compared with existing retrofit techniques. Results showed that the newly-developed slot-angle technique has significant potential for effectively reducing the stress concentrations in the web-gap region which by moving the location of the initial stress concentrations and potentially redistributing those stresses over a wider area.