Static field test on flexural behavior of reinforced concrete T-beam bridge strengthened with MPC-PSWR

PurposeWith the rapid development of transportation and the continuous increase of traffic volume and load level, some bridges cannot meet the use requirements, and the demand for bridge strengthening is growing. Furthermore, bridges are affected by factors such as structure and external environment. With the increase of service time, the deterioration of bridges is also increasing. In order to avoid the waste caused by demolition and reconstruction, it is necessary to strengthen the bridge accurately and effectively to improve the bearing capacity and durability, eliminate the hidden dangers, and ensure the normal operation of the bridge. It is of great significance to study the strengthening methods. Compared with traditional strengthening methods, the advantages of using new materials and new technology to strengthen bridges are more obvious. This paper introduces a new method for bridge active strengthening, called modified polyurethane cement with prestressed steel wire rope (MPC-PSWR).Design/methodology/approachRelying on the actual bridge strengthening project, five T-beams of the superstructure of the bridge are taken as the research object, and the T-beams before and after strengthening are evaluated, calculated, and analyzed by finite element simulation and field load test. By comparing the numerical simulation and load test data, the strengthening effect of modified polyurethane cement with prestressed steel wire rope on stiffness, strength, and bearing capacity is verified, which proves that the strengthening effect of MPC-PSWR is effective for strengthening.FindingsMPC-PSWR can effectively reduce deflection, cracks, and strain, thereby significantly improving the flexural capacity of existing bridges. Under the design load, the deflection, crack width, and stress of the strengthened beams decrease in varying degrees. The overall performance of the beams strengthened by MPC-PSWR has been improved, and the flexural performance meets the requirements of the code.Originality/valueMPC-PSWR is an innovative bridge-strengthening method. Through the analysis of its MPC-PSWR effect, the MPC-PSWR method with reference to significance for the design and construction of similar bridges is put forward.

Development of a Prestressing CFRP Laminate Anchorage System and Bridge Strengthening Application

For prestressed carbon fiber reinforced polymer (CFRP) tendon anchorage systems to become well established and used on a large scale, practical requirements for structure strengthening may be met by performing a relatively easy anchorage technique using prestressing CFRP laminates. From testing performed on a clip-type CFRP laminate anchorage system developed in our research group, it was revealed that this system could achieve the anchorage efficiency and the relaxation met the requirement of specification. Furthermore, the relevant indices of the anchorage system met the prestressed system standards. A test on the load-carrying capacity of a full-scale model beam demonstrated that the load-carrying capacity of the beam increased by more than 60% after it was strengthened with the anchorage system. The prestressing CFRP laminates and the bridge structure deformed and bore stress as a composite and exhibited excellent operating performance when working together.