Prestressed concrete planks using CFRP tendons were used to replace badly deteriorated hollow core planks for the access ramp to the University of Wyoming football stadium. The test program for the planks is described followed by the issues associated with the construction and installation of the replacement planks. The planks have been in service for five years and no signs of deterioration have been observed.

The need for sustainable structures is the driving force for the growing international interest in using advanced materials such as fiber reinforced polymer (FRP) materials for civil infrastructure applications. To date, FRP materials have not realized their full potential within the construction industry. One of the contributing factors is the limited information regarding their long-term performance. In particular, since the service life of a civil engineering structure is typically 50 to 100 years, knowledge of the long-term durability of FRPs is of prime importance. The research work presented in this paper is the result of a research collaboration between North Carolina State University and the University of Cambridge. The research investigates the durability of concrete beams prestressed with CFRP bars and compares the results with those of companion beams prestressed with steel wires. A total of 15 beams have been constructed and tested under different mechanical and environmental conditions. The parameters included in the program were the level of sustained stress in the bars and wires (55 and 70 percent of the ultimate bar or wire strength), the environmental exposure condition (air exposure and continuous exposure to 15 percent by mass salt water spray at 54 °C temperature), the length of time under sustained load (9 and 18 months) and the method of testing (with or without application of cyclical loading prior to static testing to failure). The experimental program illustrates that CFRP prestressed concrete beams exhibit comparable ultimate strength and fatigue strength properties in comparison to equivalent steel prestressed concrete beams. Furthermore, test results show that the beams prestressed with steel wires did not survive the environmental exposure over 12 months whereas the beams prestressed with CFRP bars survived up to the end of the 18 month long extreme environmental exposure, indicating the excellent durability of CFRP in the marine environment. Provided that provision is made for the lack of CFRP ductility in comparison to steel, the research undertaken has indicated that CFRP prestressed concrete is a durable, appropriate option when designing structures for use in offshore environments.

Use of non-metallic (FRP) reinforcements provides a promising alternative in order to avoid corrosion in reinforced concrete. By applying non-metallic (FRP) reinforcements there is no ferrous material to corrode in reinforced concrete. This paper reviews experiences with Carbon Fiber Reinforced Polymers (CFRP) for precast prestressed concrete girders. An experimental program was completed at the Budapest University of Technology and Economics, Faculty of Civil Engineering to study service behavior of precast concrete beams prestressed with CFRP tendons in terms of both load vs. deflection responses and cracking behavior. In this paper deflection control is presented with an introduction of a new simplified method and discussion of pivot hysteresis behavior under cyclic loading.

This paper summarizes the experimental and analytical research work for simulating a recently built retaining masonry wall post-tensioned with carbon fiber reinforced polymer (CFRP) tendons. A group of creep and shrinkage experiments on masonry prisms similar to that used in the masonry diaphragm wall is discussed. A theoretical investigation using numerical models to describe the time-dependent deformations of the masonry diaphragm wall was performed. Creep coefficients based on the experiments are compared to common creep values based on other research investigations and on well established code models. A finite element model of the masonry diaphragm wall was developed incorporating the non-linear time-dependent properties of masonry to investigate the long-term deformations and stress redistribution in the walls over time. Deformations of the walls are compared to observations from a continuous monitoring system observing the lateral deformations and strains and stresses of the wall.

The monotonic flexural performance of reinforced concrete beams strengthened with external post-tensioned CFRP tendons was investigated. Variables include straight and double draped tendon profiles, and two post-tensioning conditions: at service load (50% of the yielding capacity - in-service beam) or after overloading to twice the steel reinforcement yield strain (overloaded beam). The beams were tested to failure in four-point bending. Experimental results indicated that the tendon profiles investigated did not affect the beam behavior. Overloading of the beam prior to post-tensioning had a significant effect on the deflection capacity of the beam, with a slight effect on the yield and ultimate capacities. A strain reduction approach, developed previously for unbonded steel tendons, was extended to model the beam behavior. The loading history of the beam prior to strengthening was explicitly accounted for in the model. The analytical predictions showed good agreement with the experimental values.