钢-混凝土组合梁负弯矩区有效翼缘宽度的研究  

STUDY OF THE SHEAR LAG EFFECT AND THE EFFECTIVE FLANGE WIDTH AT NEGATIVE MOMENT ZONE OF STEEL-CONCRETE COMPOSITE BEAMS

作　　者：张彦玲[1,2] 李运生[1,3] 樊健生[3] 季文玉[2] 

机构地区：[1]石家庄铁道学院土木工程分院,石家庄050043 [2]北京交通大学土建学院,北京100044 [3]清华大学土木工程系,北京100084

出　　处：《工程力学》2010年第2期178-185,共8页Engineering Mechanics

基　　金：国家自然科学基金项目(50408001)

摘　　要：根据等效跨度的概念,采用能量变分法,考虑翼板开裂及钢梁与混凝土板之间相对滑移的影响,推导了反向集中荷载作用下截面应力的解析解,计算了组合梁负弯矩区的有效翼缘宽度,将计算结果与试验结果进行了对比,并分析了组合梁负弯矩区混凝土开裂对剪力滞效应和有效翼缘宽度的影响。分析表明:混凝土开裂使组合梁负弯矩区剪力滞系数较开裂前减小,有效翼缘宽度较开裂前增大,但开裂区域长度对开裂部位的剪力滞系数和有效翼缘宽度无影响,故有效翼缘宽度可在负弯矩区等效跨度范围内按完全开裂的等截面梁进行计算,但在连续组合梁中,等效跨度应充分考虑实际反弯点的位置,完全按规范取定值在某些工况下会引起较大误差。Using the energy-variation principle and considering the influence of the concrete cracking and the slip effect between the steel girder and concrete slab, the analytical stress solutions of the beams under the concentrated load are obtained based on the concept of effective span length, and the effective flange width at negative moment zone of composite beams is also developed. All the numerical results are compared with the test results, and the influence of concrete cracking on the shear lag effect and the effective flange width are investigated. The study suggests that the concrete cracking leads to a smaller shear lag coefficient and a larger effective flange width, while the length of the cracking zone has not much influence on the shear lag coefficient and the effective flange width. It is also found that the effective flange width can be calculated by using a completed cracked beam with a uniform cross-section in the range of effective span length corresponding to the negative moment zone. The actual position of inflection point should be carefully considered for the continuous composite beam. Using the fixed values of the effective span length given in the design codes may involves significant errors in some cases.

关 键 词：钢-混凝土组合梁 有效翼缘宽度 能量变分原理 负弯矩区 开裂 剪力滞 

分 类 号：TU398.9[建筑科学—结构工程]