The interest in using fiber reinforced concrete (FRC) for the production of precast segments in tunnel lining, installed with Tunnel Boring Machines (TBMs), is continuously growing, as witnessed by the studies available in literature and by the actual applications. The possibility of adopting a hybrid solution of FRC tunnel segments with Glass Fiber Reinforced Polymer (GFRP) reinforcement is investigated herein. Full-scale tests were carried out on FRC segments with and without GFRP cage, with a typical geometry of metro tunnels. In particular, both flexural and point load full-scale tests were carried out, for the evaluation of the structural performances (both in terms of structural capacity and crack pattern evolution) under bending, and under the TBM thrust. Finally, the obtained results are compared, in order to judge the effectiveness of the proposed technical solution.

This paper attempts to investigate the effectiveness of Steel Chip Reinforced Polymer Cementitious Composite (SCRPCC) to reduce the seismic drift of high rise building by employing finite element method. Steel chips are produced when a steel plate is precisely machined on a numerically controlled lathe. To verify the influence of drying shrinkage on the structural performance of entire buildings, seismic response analyses of a 22-story RC wall building subject to drying shrinkage cracking are conducted. The analyzed building was damaged in 1985 Mexico Earthquake. In the analyses, drying shrinkage is considered by conducting the drying shrinkage cracking analyses before dynamic seismic vibration analyses to examine the influence of drying shrinkage. For each case of the analyses, two kinds of materials are used; ordinary concrete and SCRPCC. The shrinkage of 8,400-day drying period induces cracks in the walls of top floor as well as the first floor. The maximum drift of the building is increased in the NS direction by the shrinkage cracking while reduced in the EW direction. The maximum total drift of the building during the seismic vibration is reduced by 3.5% in the NS direction and 8.9% in the EW direction by using the SCRPCC instead of the ordinary concrete. The average crack width of the building is reduced by 11.1% by the SCRPCC.

Recently the use of special reinforcement arrangements has been extended in reinforced concrete members under torsion. These arrangements include (a) continuous rectangular spiral reinforcement, (b) epoxy bonded Carbon Fiber Reinforced Polymer (C-FRP) sheets as external transverse reinforcement and (c) short steel fibers as mass reinforcement. In this study an extended experimental program of 14 beams tested under torsion is presented. All specimens have the same geometrical characteristics but different transverse reinforcement arrangements. Six beams are used as pilot specimens; three of them have no transverse reinforcement and three have conventional steel stirrups. Further, two specimens have continuous steel spirals; four specimens have steel fibers as mass reinforcement and two specimens have externally bonded C-FRP sheets. The torsional behavior of these specimens is presented and compared to the behavior of the pilot specimens. Discussion and explanatory design examples about the application of these reinforcements are also included.

With over 80 years of history, it is only in the last 20 years that the use of fiber reinforced polymer (FRP) materials has become feasible for bridge applications in part due to the ever increasing requirement to make structures last longer, with the current American Association of State Highway Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Bridge Design Specifications requiring that structures be designed for a 75 year design life; but also in the development of cost effective production techniques, and the introduction of FRP materials, which bring the cost and strength of FRP materials closer to traditional steel reinforcement. Published documents provide comprehensive recommendations on design methodology, predictive equations, and recommendations for strength and service limits states. In this paper, the background of FRP-prestressed concrete bridges is discussed and trial bridges are designed. Research needs to advance the state of the art are identified and delineated.

Fire is a possible hazard on highway bridges which causes significant economic damage, and it is also one of the least investigated of all hazards. There is a lack of knowledge on the long term performance and structural integrity of fire damaged and fiber reinforced polymer (FRP) laminate retrofitted bridges. One such rare in-service bridge was selected for this study. The fire damaged cast-in-place non-prestressed girders were previously repaired with mortar and strengthened with FRP wrapping. The girders were instrumented with strain gages and displacement transducers, and a non-destructive live load test was carried out to evaluate the structural response. The results from the load testing were used to compare two identical girder spans with and without CFRP strengthening. A full-scale non-linear finite element model of the overall bridge superstructure was created, and the test results used to calibrate the model. The carbon (CFRP) strengthened girder exhibited similar stiffness compared to the undamaged girder as evidenced by almost equivalent mid-span deflection. The girder moment capacity decreased significantly due to fire damage, and the CFRP strengthening plus mortar repair was successful in restoring the moment capacity. The finite element model provided good correlation with load test results.