混凝土扭转剪切徐变试验方法及其应用

Concrete Torsion Shear Creep Experimental Method and Application

为研究大跨径混凝土梁桥在长期变形分析时剪切徐变的影响,针对剪切徐变系数的取值问题,提出一种基于扭转的剪切徐变试验装置和测试方法,并开展三组混凝土试件的剪切徐变试验研究;获取375d的徐变系数曲线,利用现行规范模型的参数修正,对剪切徐变的发展规律进行分析,并通过有限元对结果进行验证.研究结果表明:基于扭转的剪切徐变试验装置可对构件进行有效加载;通过扭转剪切得到的徐变系数计算公式可用于试验数据分析;C30混凝土试验剪切徐变终极值为规范轴压徐变终极值的2.26~2.63倍,剪切徐变在受荷早期的发展低于轴压徐变,但后期逐步加速;受扭构件等剪切影响显著的结构徐变计算应考虑剪切徐变效应.

To study the effect of shear creep on long-term deformation of large span concrete bridge, aiming at the problem of shear creep coefficient, an experimental device and test method based on torsion was proposed for shear creep test. Three groups of shear creep members were tested to obtain creep coefficient curve lasted in 375 days. And based on the modification of axial compression creep model of current specification, the rules of shear creep progress was analyzed with finite element(FE) analysis verification. The results show that the shear creep test device based on torsion can be used to load the concrete element effectively. And creep coefficient formula deduced from torsion creep can be used for test data analysis. The C30 concrete shear creep ultimate value is 2.26~2.63 times of specification compression model. The early aged shear creep progressed smaller than compression creep, but accelerated in the later age. Torsion and other significantly shear effected structures should consider shear creep action in creep analysis.