体外预应力高强混凝土薄壁箱梁试验研究

进行了体外预应力高强混凝土薄壁箱梁从预应力钢绞线张拉到承载力极限破坏这一全过程的试验研究,研究了体外预应力损失及应力增量、跨中截面应力—应变分布以及跨中挠度和抗裂性能等问题。研究结果表明:体外预应力高强混凝土薄壁箱梁预应力损失实测值与现行规范计算值基本吻合,探讨了其截面受压翼缘有效分布宽度和体外预应力筋应力增量的变化规律,初步揭示了体外预应力高强混凝土薄壁箱梁在混凝土开裂前和受拉非预应力钢筋屈服后混凝土受压翼缘存在不同的剪力滞效应,并提出了相应状态下的受压翼缘有效分布宽度系数。

Experimental research on the externally prestressed high-strength concrete thin-walled box girder

A full rang of behaviors of high-strength concrete box girder prestress with external tendons have been tested. The crack patterns,deflection,strain and stress distribution,prestressing loss and stress increment of external tendons have been measured. The results demonstrate that measured prestressing loss agrees well with the present highway bridge design code of China,besides,the shear lag effect in compressive flange and the stress increment in external tendons during the fully loaded range of the box girder also have been obtained from the experimental study and reasonable effective width for compressive flange relative to different stages has been proposed based on the measured results.