Functionality of Damaged Steel Truss Systems Strengthened with Posttensioned CFRP Tendon

Abstract

This paper presents the functionality of truss systems damaged and strengthened with carbon fiber reinforced polymer (CFRP) tendon. Sixteen damage scenarios are designed by disconnecting various web members of a laboratory-scale truss. A posttensioning technique is proposed using steel tubes and non-shrink mortar embedded with the CFRP. Tension tests are conducted to evaluate the feasibility of the anchorage. Experimental trusses are monotonically loaded in service and a three-dimensional finite-element model is constructed to simulate the test data. Deflection characteristics of the truss system are influenced by the presence of local damage. The proposed posttensioning method enhances the serviceability of the strengthened truss system by reducing decompression–deflection. However, the level of posttension force is not related to the flexural stiffness of the truss from a practical perspective. Stress redistribution is observed in the truss system due to the CFRP strengthening, including a load-sharing mechanism among the members. CFRP strengthening enhances structural redundancy and functional performance of the truss systems.