高强钢筋UHPC梁抗弯性能试验研究与理论分析

Flexural Test and Theoretical Analysis of UHPC Beams with High Strength Rebars

为研究将高强钢筋用于超高性能混凝土(UHPC)的可行性,通过6根梁的正截面抗弯试验,研究了配筋率、截面形式(矩形与T形梁)等对抗弯性能的影响规律.试验结果表明,HRB500级钢筋与UHPC适配良好,可充分发挥两者高强性能;配筋率对开裂荷载影响小,但可显著提高梁的极限承载力;为防止梁发生斜截面破坏,需要按计算配置箍筋;UHPC梁裂缝细而密,考虑受拉区UHPC塑性变形而建立的开裂弯矩公式与实测值吻合良好;据简化的UHPC本构模型建立的正截面极限承载力公式,预测精度较高.

In order to study the feasibility of using high-strength rebars with ultra-high performance concrete（ UHPC ）, 6 test beams were prepared to investigate the influence of reinforcement ratio, shape of cross-section （rectangular and T-shaped ）and other factors, on the flexural properties of the beams. The results showed that HRB500 grade rebars with UHPC obtained excellent results when used together, since their high strength properties could be fully utilized; Influence of reinforcement ratio on the cracking load was little, but could significantly improve the ultimate capacity of the beam;In order to prevent the shear failure of inclined section, stirrups reinforcement was needed and its amount should be well determined; UHPC beam cracks were fine and dense.Considering the plastic deformation of UHPC in the tension zone, a formula for calculation of initial cracking moment of UHPC beams was established, which was in agreement with test values. According to the simplified constitutive model of UHPC, ultimate bearing capacity formula with high prediction accuracy was established.