A Case Study of Bridge Strengthening through the Use of Post-Installed Shear Connectors

This paper presents a summary of a project where post-installed shear connectors were used to strengthen an older non-composite steel girder bridge located near the town of Hondo, Texas. The use of post-installed shear connectors permits the development of composite action between the existing steel girders and the existing reinforced concrete deck, thereby increasing the flexural strength of the girders. The very good fatigue strength of these post-installed shear connectors enabled the use of partial composite design. As a result, far fewer post-installed shear connectors were needed than if conventional welded studs were used. For this bridge, the addition of post-installed shear connectors resulted in approximately a 65-percent increase in the Inventory and Operating level load ratings. Also presented in this paper are load test results which were conducted to verify composite action at the steel-concrete interface after the retrofit and compare the structural behavior of the bridge before and after the retrofit.