This paper presents a study on the failure load and deformation of CFRP box beams based on the fracture of individual laminas. Three different shear spans of cross ply (CP) laminate structures are tested and analyzed. Nonlinear constitutive law is obtained by considering the fracture of individual lamina, and the law is implemented into a fiber model to obtain the failure load of the beams under different shear spans. The fiber model is also used to obtain the flexural deformation of the beams, while Timoshenko beam is referred to obtain the shear deformation. Analysis shows a fair agreement on load-displacement relations and failure patterns, although a slight difference is observed under short shear spans.

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 Top coating on GFRP has protective effect in outdoor environment, however its protective mechanism is not well known in the detail yet. The authors carried out an outdoor exposure test using three types of pultruded GFRP having varied layer systems with or without top coating for 10 years. Retrieved specimens were evaluated their deterioration state with visual observations with naked and microscope. Mechanical properties such as tensile test and in-plane shear test and immersion test for retrieved specimens were carried out in order to evaluate the protective effect of top coating, especially its shield performance against water and light of top coating.

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 The objective of this study is to investigate the utilization of high-elongation and low elastic putty as standard specification in a repair method using CFRP sheet for corroded steel members subject to axial force or normal stress under bending. If it is aimed to reduce stress level in a steel member such as the case when the putty is not used, necessary bond length of CFRP sheet is too long. Therefore, considering workability, a new stress reduction factor is introduced to conventional design. In order to decide the factor, parametric analysis is performed using a numerical calculation method proposed by the first author. After comprehending the influence of parameters, the factor in the repair design is determined. Furthermore, effective CFRP bonding repair method using high-elongation and low elastic putty or tapering is studied for axial member with steep cross-section loss.

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 Installation of FRP hydraulic gates started in the 1960s, and almost seven hundred gates are now under operation in Japan. FRP gates have better durability when compared with steel gates and sometimes life cycle cost advantages, while their applications are limited to small or middle-sized structures. Mobility in construction and operability due to the lightweightness are also strong points. However, current technical standards for hydraulic gates do not provide specific design details concerning FRP gates.
 Our subcommittee formulated guidelines for FRP gates, which cover design, construction, inspection and maintenance. The guidelines are described based on the allowable stress design method employed in the current practice, and the guidelines based on the performance-based design method employed in the standard specifications for hybrid structures by JSCE are provided as well.

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 FRP has some outstanding properties in anti-corrosive performance under severe environments and light weight comparing with the other conventional structural materials; however, FRP's mechanical characteristics are quite different from those of steel or concrete, because of the difference in manufacturing method of FRP. This situation, therefore, required the expansion of the basic data of FRP as a structural materials including the establishment of the reliable partial safety factors for the structural design of FRP members. However because FRP was still rather new material in construction comparing with other construction materials, the expansion and improvement of comprehensive database on the behavior of FRP members as a structural materials were still important issue.
 The subcommittee on FRP hybrid structure investigated the fluctuation factors of the mechanical properties of FRP members, and enriched the basic data that will be utilized for the determination of partial safety factors of FRP as a structural materials through carrying out literature surveys, market researches and many loading tests.

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 The subcommittee on investigation research of design method for upgrading concrete structures with use of FRP at committee on Hybrid structures in Japan Society of Civil Engineers worked on research for total approximately four years from June, 2010 to May, 2014. During the first term for two years, the subcommittee pointed out the issues of existing design method by upgrading FRP material. Based on that discussion, the information to help rationalization of the design method was provided in next second term for two years. This report outlines the subcommittee report on “Current trend and future issue for upgrading concrete structures with use of FRP at committee on Hybrid structure”, published as Hybrid structure report 12.

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