In this study, 12 high-strength concrete dapped-end beams were tested to study the effects on shear strength of dapped-end beams of the concrete strength, the amount of main dapped-end reinforcement, and the nominal shear span-to-depth ratio. The test results indicate that the shear strength of dapped-end beams increases with the increase of the concrete strength, the amount of main dapped-end reinforcement, and the decrease of nominal shear span-to-depth ratio. An analytical model for determining the shear strength of reinforced concrete dapped-end beams is also proposed. Both the shear strengths predicted by the proposed model and the approach of the PCI Design Handbook are compared with test results of this study and those of Mattock and Chan (1979). The comparison shows that the proposed model can predict the shear strength of reinforced concrete dapped-end beams more accurately than the approach of the PCI Design Handbook.

The test results of 24 reinforced concrete dapped-end beams are reported. The main variables studied were the compressive strength of concrete, the shear span-to-depth ratio and the horizontal load. The test results indicate that the shear strength of dapped-end beams increases with an increase in concrete compressive strength. The shear strength of dapped-end beams also increases with decreases in shear span-to-depth ratio and horizontal load. The smaller the shear span-to-depth ratio of dapped-end beams, the greater their stiffness and ultimate load. Both the stiffness and the ultimate load of dapped-end beams increase with increasing concrete compressive strength, but decrease with an increase in horizontal load. The extension of the softened strut-and-tie model for predicting the shear strength of dapped-end beams with a shear span-to-depth ratio greater than unity is examined in this paper. The shear strength predicted by the proposed model, the strut-and-tie model of the American Concrete Institute (ACI) and the approach of the Precast/Prestressed Concrete Institute (PCI) are compared with available test results. The comparison shows that the proposed model and the strut-and-tie model can predict the shear strength of reinforced concrete dapped-end beams more accurately than the PCI approach.

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Purpose The purpose of this paper is to propose a hybrid decision-making model for optimizing the initial design strategies of pre-sales housing, identifying factors affecting the initial design of housing, and developing different initial design approaches and strategies based on buyers’ preferences. Design/methodology/approach Indicators and factors in line with the local initial planning and design are created according to the design quality indicator framework. The important indicators and factors are screened out preliminarily with the fuzzy Delphi method and decision-making trial and evaluation laboratory based analytic network process. The performances of two actual cases under similar site conditions are checked with regard to the overall residential sales rate and time on the market (TOM). Findings The result shows that the proposed model can effectively improve the sales rate, shorten the TOM and better complies with buyer design strategy demands, and thus positively correlating to economic value. Originality/value Pre-sales make possible the customized strategy of allowing future residents to participate in the housing design process. However, buyers’ participation in the design process is highly limited, and developers usually determine their planning and initial residential design strategies based on experience and intuition. With the proposed approach, the initial residential design of a project can be effectively intervened, so that home users can truly participate in the design, and the residential construction service can be provided in a unique, but non-universal way.

In this study, 15 reinforced concrete corbels with shear span-to-depth ratio greater than unity were tested. Test results indicate that the shear strength of corbels increases with increase in compressive strength of concrete, parameter of main reinforcement and parameter of vertical stirrups. The shear strength of corbels also increases with decrease in shear span-to-depth ratio. An analytical model for determining the shear strength of reinforced concrete corbels is also proposed in this paper. Both the shear strengths predicted by the proposed model and the approach of the ACI code are compared with available test results. The comparison shows that the proposed model can predict more accurately the shear strength of reinforced concrete corbels than the approach of the ACI code.