密布预应力束锚具下混凝土局部受压承载力计算方法  

Calculating method of the local bearing capacity of concrete under closely spaced anchorages

作　　者：郑文忠[1] 张吉柱[2] 

机构地区：[1]哈尔滨工业大学土木工程学院,黑龙江哈尔滨150090 [2]中国建筑科学研究院建筑结构研究所,北京100013

出　　处：《建筑结构学报》2004年第4期60-65,共6页Journal of Building Structures

基　　金：国家自然科学基金资助项目(50178026)。

摘　　要：针对广大结构工程师在应用规范公式计算密布预应力束锚具下混凝土局部受压承载力时所遇到的问题,利用已有试验数据,经大量试算和归纳,提出了计算密布预应力束锚具下混凝土局部受压承载力的“整体计算法”和“分别计算取和法”。计算分析表明,当仅有两个局压荷载且局压荷载净距与单个局压荷载分布长度之比不大于0.6及三个和三个以上局压荷载的相邻二局压荷载净距与单个局压荷载分布长度之比不大于0.5时,锚具下混凝土中峰值横向拉应力位于局压荷载合力的正下方,局部受压承载力计算应按“整体计算法”考虑。当仅有两个局压荷载且局压荷载净距与单个局压荷载分布长度之比大于0.6时,在两个局压荷载的下方分别出现了峰值横向拉应力,局部受压承载力计算应按“分别计算取和法”考虑。当三个和三个以上局压荷载的相邻二局压荷载的净距与单个局压荷载分布长度之比介于0.5～2.0之间时,在两个边端局压荷载下方出现了明显的横向峰值拉应力,各中部局压荷载下方横向拉应力分布较均匀、且明显小于边端局压荷载下方的横向拉应力峰值,局部受压承载力计算也可按“分别计算取和法”考虑。On the basis of available experimental data and lots of calculation results and conclusions, the‘integral calculating method’and the‘sum of each individual calculating method’of calculation of the local bearing capacity were dveloped to solve problems that engineers met when calculating the local bearing capacity of concrete under closely spaced anchorages using the code formulae.Based on calculation and analysis, the following conclusions were drawn. When the maximum values of the transverse tensile stresses in concrete under anchorages are located below the resultant force of local loads, and the ratio of clear distance of local loads to distribution length of single local load is not larger than 0.6 in the condition of only two local loads, or the ratio of clear distance of local loads to distribution length of single local load is not larger than 0.5 in the condition of three or more loads, the‘integral calculating method’ is recommended to calculate the local bearing capacity of concrete. When the maximum values of the transverse tensile stresses are located below each local load and the ratio of clear distance of local loads to distribution length of single load is larger than 0.6 in the condition of only two loads, the‘sum of each individual calculating method’ is recommended to calculate the local bearing capacity of concrete. When the maximum values of the transverse tensile stresses are located below the two local edge loads in the condition of three or more loads, and the tensile stresses under local interior loads are uniform and smaller than those under local edge loads and the ratio of clear distance of local loads to distribution length of single load varied between 0.5 to 0.2, the ‘sum of each individual calculating method’ is recommended to use in calculation.

关 键 词：锚具 混凝土 受压承载力 预应力束 荷载 

分 类 号：TU378.1[建筑科学—结构工程]