施工误差对RC框架结构层间位移角限值可靠度的影响研究

施工质量的变异性是造成钢筋混凝土框架结构体系可靠度不确定的重要原因之一。结合增量变异性分析方法,考虑施工质量的随机性,利用ANSYS有限元软件,考虑各楼层的失效相关性,对钢筋混凝土框架结构的体系可靠度进行计算,分析层间位移角对施工质量的灵敏性,定量地说明施工质量的变异性对框架结构的体系可靠度的影响,并基于可靠度理论对施工误差限值进行了研究,得到了钢筋混凝土框架结构施工误差限值建议值。研究结果表明:材料强度和结构几何尺寸的随机性对框架结构楼层层间位移角均具有较大影响,尤其是混凝土抗压强度。体系可靠度随混凝土抗压强度的均值增大逐渐增大,随标准差的增大而减小。截面尺寸、箍筋间距的均值变异性对整体可靠度的影响也较明显,其次就是钢筋保护层标准差的变异。施工误差限值的建议值为:梁柱截面高度偏差限值为(-6,12)mm,箍筋间距偏差限值为(-26,26)mm,保护层厚度偏差限值为(-5.5,5.5)mm。

Research on Influence of Construction Error on Reliability of Threshold Limits forInter-Story Drift Angle of RC Frame Structure

For reinforced concrete frame structures, the variability of construction quality is one of the important reasons for the uncertainty of system reliability. In this paper, based on the analyzing method of incremental variability, the finite element software ANSYS was used to calculate the seismic reliability of reinforced concrete frame structures, considering the variability of construction quality and the failure correlation of each floor. The sensitivity of inter-story drift angle and the influence of the variability of construction quality on the system reliability were investigated quantitatively. Based on the reliability theory, the recommended threshold limits of construction error of reinforced concrete frame structures were obtained. The results show that the randomness in material strength and geometric size of structures has a great influence on the inter-story drift angle, especially the compressive strength of concrete. The system reliability increases with the mean value of concrete compressive strength and decreases with the increase of standard deviation. The mean variability of the section size and the stirrup spacing has an obvious effect on the system reliability, followed by the variation of the standard deviation of the cover thickness of reinforcements. The recommended threshold limits of construction error are (-6, 12) mm for the deviation of the height of beam-column sections, (-26, 26) mm for the deviation of stirrup spacing, and (-5.5, 5.5) mm for the deviation of the cover thickness of reinforcements, respectively.