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本文根据十二片具有不同预应力值的无箍筋和有箍筋T形截面预应力混凝土梁的试验结果,分析了预应力值对无箍和有箍筋梁抗剪强度的有利作用,证明与β_1成线性关系。本文建议把Q_(f2)~S做为无箍筋和有箍筋梁混凝抗剪强度Q_h来考虑。以此为基础,对无箍筋T梁抗剪强度Q_h和有箍筋T梁抗剪强度Q_(hh)提出了计算建议。同时,将试验结果和计算建议与国内外规范进行了比较。预应力混凝土梁正截面抗弯强度是较为明确的。但是它在弯矩和剪力共同作用下斜截面抗剪强度尚不能准确地预测。虽然国内外对抗剪强度问题曾进行过许多试验研究,在各国的设计规范中也都反映了一些科研成果,可是,由于问题过于复杂,至今还没有一个普遍公认的计算方法。按照各国规范及建议计算需用箍筋的数量仍然是相差很大的。为了配合《铁路桥涵设计规范》的修订工作,结合我国铁路预应力梁标准设计的特点,进行了T形截面预应力混凝土模型梁的抗剪性能的试验研究。
Based on the experimental results of twelve prestressed concrete beams with stirrups and stirrups with different prestress values, this paper analyzes the beneficial effect of prestress values on the shear strength of hoop-free beams and beams, and proves that Linear relationship with β_1. In this paper, we consider Q_ (f2) ~ S as the concrete shear strength Q_h of stirrup and stirrup with stirrups. Based on this, the calculation suggestion is proposed for the shear strength Q_h of stirrup T beam and the shear strength Q hh of stirrup T beam. At the same time, the test results and calculation suggestions are compared with those at home and abroad. The flexural strength of the prestressed concrete beam is more clear. However, its shear strength under oblique moment and shear force can not be accurately predicted. Although there have been many experimental researches on the shear strength at home and abroad, some scientific achievements have also been reflected in the design norms of other countries. However, due to the complexity of the problems, there is not yet a generally accepted calculation method. According to national norms and recommendations to calculate the number of stirrups still vary greatly. In order to cooperate with the revision of “Code for Design of Railway Bridges and Culverts”, combined with the characteristics of China’s standard design of prestressed railway beams, the experimental research on the shear resistance of T-shaped prestressed concrete beams is carried out.