Repair and Retrofit of Bridge structural elements: New Cementitious Materials

The condition of infrastructure, the constant need to repair and maintain them and the increasing costs associated with the maintenance has led to the search for replacements for steel in new concrete infrastructure around the world. Further, alternatives for repair and strengthening of existing concrete structures ranging from the use of FRP as plates or fabrics wraps to the use of ultra‐high‐performance concrete (UHPC) elements as external reinforcements to achieve requisite strength and serviceability requirements are being attempted. The present study evaluates the performance of repaired/retrofitted structural concrete elements and sub‐assemblages damaged in flexure or shear using different repair schemes including those based on use of FRP plates or wraps, UHPC elements, etc., to restore the capacity of damaged structural concrete elements. An ANSYS based finite element model that accounts for both the constitutive properties of the primary structure in its damaged state and the repair material is used in this study to assess the different repair schemes. The analysis is shown to predict the test results very well. The importance of considering bond slip between rebar and surrounding concrete in the analysis is highlighted. Likewise, the consequence of bond between repair material and the primary structure on the overall structural performance is clearly seen. Performance of normal and high performance of concrete under high temperature resulting in spalling and significant damage from a fire and its rehabilitation with geopolymer concrete will be shown in lab scale tests and simulations. Finally, a field application of load testing of a defunct masonry arch bridge, its retrofit strategy and subsequent deployment with cementitious mixes as a repair to operationalise the bridge with significant cost saving will be illustrated.