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采用体外预应力竖向张拉双折线布筋加固方法,对2根对比梁和9根不同体外预应力配筋率、不同工况下矩形钢筋混凝土简支梁进行了抗弯性能试验研究。试验结果表明,采用体外预应力加固RC梁可以显著提高其极限承载力和抗裂能力。在试验结果基础上,运用应力图形分解法,结合内力及力矩平衡,推导了体外预应力混凝土矩形截面梁开裂弯矩的简化计算公式,且计算值与试验值吻合良好。
The bending strength of rectangular reinforced concrete simply supported beam under different working conditions was tested by two contrasting beams and nine different ratios of prestressed reinforcement in vitro using the method of vertical pretensioned double crease reinforcement in vitro. The experimental results show that the RC beams strengthened with prestressed external reinforcement can significantly improve the ultimate bearing capacity and crack resistance. Based on the experimental results, a simplified formula for calculating the cracking moment of externally prestressed concrete rectangular cross-section beams is deduced by means of stress graph decomposition, combined with internal forces and moment balances. The calculated values are in good agreement with the experimental values.