In the present study, an experimental investigation was carried out to evaluate the flexural and shear capacity of near surface mounted (NSM) reinforced concrete (RC) beams using carbon fibre reinforced polymer (CFRP) rebars. A total of 16 half scale beams were tested to study the flexural and shear responses of strengthened RC beams. The CFRP rebars were manufactured at structural testing centre using locally developed twisting equipment to strengthen the RC beams. Also, new anchor system was locally developed to predict the tensile characteristics of CFRP bars using universal testing machine. To examine the flexural and shear behaviour, all beams were tested under two-point loading system. It was observed that the NSM strengthened RC beams have higher load carrying capacity than the corresponding control beam in flexure and shear by 68% and 35.6%, respectively. Typical failure modes of the beams during the experimental investigation were CFRP rupture, CFRP debonding, crushing of concrete and shear failure. Finally, a design example has been presented for better understanding in the analysis and design of NSM FRP strengthened RC beams. Further, the values obtained from the analytical study are in good agreement with the experimental values.Keywords: beam; composite; design example; flexure; NSM-FRP; performance; strengthening; shear; sustainable materials.Reference to this paper should be made as follows: Singh, S.B., Sivasubramanian, M.V.R., Likhith Reddy, A., Chandra Prakash, K., Nagarjuna, K. and Hima Kiran, A. (2012) 'Performance of NSM-FRP RC beams in flexure and shear using locally developed CFRP rebars', Int.

In this review article, the past investigations carried out on heritage structures using Ambient Vibration Test (AVT) and Operational Modal Analysis (OMA) for system identification (determination of dynamic properties like frequency, mode shape and damping ratios) and associated applications are summarized. A total of 68 major research studies on heritage structures around the world that are available in literature are surveyed for this purpose. At first, field investigations carried out on heritage structures prior to conducting AVT are explained in detail. Next, specifications of accelerometers, location of accelerometers and optimization of accelerometer networks have been elaborated with respect to the geometry of the heritage structures. In addition to this, ambient vibration loads and data acquisition procedures are also discussed. Further, the state of art of performing OMA techniques for heritage structures is explained briefly. Furthermore, various applications of system identification for heritage structures are documented. Finally, conclusions are made towards errorless system identification of heritage structures through AVT and OMA.

The shear behavior of innovative engineered cementitious composites (ECC) members with a hybrid mix of polyvinyl alcohol (PVA) and polypropylene (PP) fibers is examined. The overall objective of the investigation is to understand the shear behavior of ECC beams with different mono and hybrid fiber combinations without compromising the strength and ductility. Four different configurations of beams were prepared and tested, including 2.0% of PP fibers, 2.0% of PVA fibers, 2.0% of steel fibers and hybrid PVA and PP fibers (i.e., 1% PP and 1% PVA). In addition to the tests, a detailed nonlinear finite element (FE) analysis was accomplished using the commercial ABAQUS software. The validated FE model was used to perform an extensive parametric investigation to optimize the design parameters for the hybrid-fiber-reinforced ECC beams under shear. The results revealed that the use of hybrid PVA and PP fibers improved the performance by enhancing the overall strength and ductility compared to the steel and PP-fiber-based ECC beams. Incorporating hybrid fibers into ECC beams increased the critical shear crack angle, indicating the transition of a failure from a brittle diagonal tension to a ductile bending.

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Results of an experimental study on flexural behaviour of steel-reinforced portal frames made of ductile fibre-reinforced cementitious composite and concrete under static transverse bending are reported in this paper. A total of six half-scale frames were cast and tested. It was observed that the frames partially or fully made of ductile fibre-reinforced cementitious composite have about 21–37% higher load-carrying capacity than ordinary concrete frames. Moreover, frames completely made of ductile fibre-reinforced cementitious composite are shown to have 1·5–2 times more ductility than the control frame. The failure modes of ductile fibre-reinforced cementitious composite frames were very ductile with multiple microcracks and the general pattern was flexural tension. In addition to the frame specimens, ductile fibre-reinforced cementitious composite tensile coupons, compressive cylinders and concrete cubes were also cast and evaluated.