• Structural Engineering and Mechanics
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• v.92 no.4
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• pp.393-404
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• 2024

To investigate the mechanical behavior of unbonded prestressed reinforced concrete (PRC) beam with high-strength spiral stirrups, the shear capacity formula of the beam was proposed in this study based on modified variable angle truss and arch models. Considering the effect of the spiral stirrups and unbonded tendons, the theoretical formula of the shear capacity of the beam was derived. Furthermore, the coefficients related to the formula, such as the equivalent angle and stress of spiral stirrups, the ratio of shear span to effective depth, and the concrete compression zone depth of the arch model were determined. The complicated theoretical formula was further simplified for ease of use by engineers. In addition, the finite element model of the PRC beam was established and verified by test data. The additional FE model of PRC beam with spiral stirrups was established and parametric analysis was carried out. Finally, the proposed formula was validated by numerical results of the beam with spiral stirrups. The calculated values of the formula are in good agreement with the numerical simulation data. This study may enrich the understanding of the shear capacity of the unbonded PRC beam with high-strength spiral stirrups.

• Steel and Composite Structures
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• v.24 no.1
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• pp.1-13
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• 2017

In order to improve the deformation capacity of the high-strength concrete shear wall, five high-strength concrete shear wall specimens confined with high-strength rectangular spiral reinforcement (HRSR) possessing different parameters, were designed in this paper. One specimen was only adopted high-strength rectangular spiral hoops in embedded columns, the rest of the four specimens were used high-strength rectangular spiral hoops in embedded columns, and high-strength spiral horizontal distribution reinforcement were used in the wall body. Pseudo-static test were carried out on high-strength concrete shear wall specimens confined with HRSR, to study the influence of the factors of longitudinal reinforcement ratio, hoop reinforcement form and the spiral stirrups outer the wall on the failure modes, failure mechanism, ductility, hysteresis characteristics, stiffness degradation and energy dissipation capacity of the shear wall. Results showed that using HRSR as hoops and transverse reinforcements could restrain concrete, slow load carrying capacity degeneration, improve the load carrying capacity and ductility of shear walls; under the vertical force, seismic performance of the RC shear wall with high axial compression ratio can be significantly improved through plastic hinge area or the whole body of the shear wall equipped with outer HRSR.

• Steel and Composite Structures
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• v.22 no.1
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• pp.45-61
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• 2016

The domestic and foreign scholars conducted many studies on mechanical properties of wave web steel beam and high-strength spiral stirrups confined concrete columns. Based on the previous research work, studies were conducted on the anti-seismic property of the end plate bolt connected wave web steel beam and high-strength spiral stirrups confined concrete column nodes applied with pre-tightening force. Four full-size node test models in two groups were designed for low-cycle repeated loading quasi-static test. Through observation of the stress, distortion, failure process and failure mode of node models, analysis was made on its load-carrying capacity, deformation performance and energy dissipation capacity, and the reliability of the new node was verified. The results showed that: under action of the beam-end stiffener, the plastic hinges on the end of wave web steel beam are displaced outward and played its role of energy dissipation capacity. The study results provided reliable theoretical basis for the engineering application of the new types of nodes.