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A design approach based on the simplified modified compression field theory, but with the advantage of not requiring an iterative procedure, is proposed for evaluating the shear capacity of beams without including shear reinforcement. This model is capable of simulating beams flexurally reinforced with steel and fiber reinforced polymer (FRP) systems. To appraise the predictive performance of the proposed model, a database (DB) composed of 215 reinforced concrete beams without shear reinforcement is set. By applying the model to this DB, an average value for V-exp./V-ana. of 1.05 with a COV of 24% is obtained, where V-exp. and V-ana. are the shear capacity registered experimentally and obtained with the model, respectively. By applying the approach proposed by ACI Building Code to the DB, average and COV values of 0.91 and 42% are determined, revealing the higher predictive performance of the proposed model. This was even higher in the beams flexurally reinforced with FRP systems, since the proposed model conducted to average and the COV values of 1.0 and 22%, while 0.76 and 32% were obtained with the ACI approach. When proposed model was applied to the beams tested in the experimental program carried out, an average and COV values of 1.02 and 5.23% were determined., The second author wishes to acknowledge the grant SFRH/BSAB/114302/2016 provided by FCT. The support of the FCT through the project PTDC/ECM-EST/1882/2014 is acknowledged., info:eu-repo/semantics/publishedVersion

This paper presents findings from an experimental study on shear properties of high-performance concrete beams reinforced with basalt fiber reinforced polymer bars and macrobasalt fibers. The test ...

The use of bamboo as longitudinal reinforcement, coupled with the application of self-compacted concrete (SCC) in the construction industry, may be a promising solution to issues involving sustainable development in developing countries. This study seeks to investigate the flexural performance of bamboo-reinforced SCC beams with adequate transverse reinforcement. The major design parameters were the shear span-to-depth ratio, the percentage of longitudinal reinforcement, and the maximum size of coarse aggregate. The load–deflection curves, serviceability and ultimate failure characteristics, cracking behavior, and ductility measures were evaluated and discussed among tested beams. Results indicated that their structural performance at service and ultimate failure would be adequate when a material reduction factor of three is used with BS 8110 design code. However, to achieve maximum ductility, the level of longitudinal reinforcement should be in range of 2.6–3.1%. Furthermore, an increase in the size of coarse aggregate will greatly impact the degree of ductility.

This paper presents a critical comparison of the existing code provisions for the shear strength of concrete beams. The comparison is based on the computerized filtering-out of the in-evitable statistical bias from the available multivariate database on shear strength, on an examination of the predicted size effects on shear strength and their underlying hypotheses and on the results of recent high-fidelity numerical simulations of shear failure. In addition to examining the existing models, the present comparison also provides several key considerations for testing the scientific soundness of any model of shear failure in concrete beams, which is necessary for future revisions to the design code provisions.

In comparison with a vibrated concrete (VC) of the same strength class, self-compacting concrete (SCC) typically has a lower coarse aggregate content and, possibly, a smaller maximum aggregate size. This may result in reduced aggregate interlock between the fracture surfaces of a SCC. Since aggregate interlock plays an important role in the shear strength of slender beams, SCC beams may have a shear strength lower than that of similar VC beams, but studies on that subject are still limited. This article summarizes an experimental programme that includes beams of high-strength SCC and transverse reinforcement ratios around the minimum given by different codes – a case that had not been investigated so far. The shear strengths of those SCC beams are compared with those of VC beams with similar concrete compressive strength and small ratios of transverse reinforcement and also compared with beams calculated according to different code procedures.

Semi-probabilistic safety formats for the non-linear analysis of reinforced concrete structures are of practical interest for structural designers. The safety format proposed in EN 1992-2 enables a safety assessment through a non-linear structural analysis and the application of a global safety factor, which is defined as the ratio between the representative and design values of the material resistances. A more realistic estimate of the global safety factor can be obtained from the distribution of the structural response. This paper proposes a safety format based on the mean values of the material resistances and a global resistance factor. Its practical application in the structural design of concrete beams and columns is also presented.