摘要
竖向预应力回缩损失过大是导致混凝土箱梁腹板开裂的主要原因之一,钢筋的回缩量与锚具安装倾角误差存在明显的对应关系。利用JMCX7121型数显倾角仪,对六座预应力混凝土箱梁桥竖向预应力安装倾角误差进行调查,共收集了2215个样本,采用截尾正态分布和皮尔逊III曲线两种假设,对样本分布规律进行回归分析,并用皮尔逊χ2检验法对两种假设进行检验。分析结果表明:竖向预应力安装倾角误差服从皮尔逊III曲线y=f(X,Cv,Cs)分布,其中X0=2.38、Cs0=0.542、Cv0=1.084,满足工程可靠度0.95的安装倾角误差为4.75°;六座大桥的锚垫板安装的施工水平相当,样本数据离散性大、施工质量不稳定。表明目前国内桥梁建设行业对竖向预应力施工不够重视。
Too much loss of vertical prestress due to anchorage slip is one of the main causes of cracking in the webs of concrete.The slip magnitude is obviously related with the inclination angle error incurred when fixing the anchorage.Investigation of such inclination errors for six prestressed concrete box bridges is conducted.2215 samples were acquired by using JMCX7121 type inclinometer to measure the angles.Regression analysis was performed assuming truncated normal distribution and Pearson-Ⅲ curve,which were appraised using the inspection method of Pearson χ2.Comparison shows that the inclination error follows the distribution of Pearson-Ⅲ curve y=f（X-,Cv,Cs）,with X-0=2.38,Cs0=0.542 and Cv0=1.084.The inclination error corresponding to the engineering confidence level of 0.95 is 4.75°.The construction for fixing the anchorages of the six bridges was similar,whereas the sample data are rather scattered,reflecting the instability of construction quality.
出处
《土木工程学报》
EI
CSCD
北大核心
2010年第5期23-28,共6页
China Civil Engineering Journal
关键词
混凝土箱梁
竖向预应力损失
安装倾角误差
统计规律
皮尔逊曲线
concrete box beam
vertical prestress loss
fixing inclination error
statistic regularity
curve Pearson-Ⅲ
