【作者】 徐悦军；

【导师】 毛小勇；

【作者基本信息】 苏州科技学院 ， 结构工程， 2011， 硕士

【摘要】 PEC柱是在型钢两翼缘之间填充混凝土而成的新型组合构件,具有承载力高、抗震性能好、经济性优越等优点,应用前景良好。由于PEC柱型钢翼缘外露,在火灾中极易发生屈曲,进而引起混凝土的压碎,导致柱强度和刚度急剧下降。因此,深入地研究PEC柱的耐火性能具有重要的理论意义和实用价值。本文主要进行了如下工作:通过分析比较国内外研究成果,确定了高温下组成PEC柱的型钢和混凝土的热工参数和力—热本构关系模型。利用有限元软件ABAQUS建立了PEC柱截面的温度场及耐火极限计算的有限元模型。计算结果得到了已有试验数据的验证。利用上述模型,分析了截面尺寸、荷载比、构件长细比、截面含钢率、荷载偏心率、钢骨强度、混凝土强度和系杆间距等参数对PEC柱耐火极限的影响规律。分析结果表明:当火灾温度按ISO-834标准升温曲线确定时,截面含钢率、荷载偏心率、钢骨屈服强度、混凝土强度和系杆间距对PEC柱耐火极限的影响不大,而截面尺寸、荷载比和长细比对耐火极限的影响较为显著。在大量参数分析的基础上,提出了PEC柱耐火极限的简化计算公式,公式的计算结果与数值计算结果吻合较好,可为PEC柱的抗火设计提供参考。更多还原

【Abstract】 Partial encaed concrete (PEC) columns is a new type of composite members consisting of welded H-shaped steel section and concrete casted between the flanges.It has distinct economic and structural advantages,such as high load bearing capacity,excellent earthquake resistance qualities.Due to the fact that steel flanges are exposed in the air ,the columns are buckling easily under fire. Leading to concrete crushing and the column strength reducing sharply. Researching on the fire resistant behavior of PEC columns is valuable for practical engineering.The main contents are as following:Based on analysis and comparison of current achievements on material behavior under high temperature, thermal properties and model of stress-strain relations for steel and concrete under high temperature were determined.A general finite element analyzing software (ABAQUS) was utilized to establish the 3D model of PEC columns. The model was used to calculate the mechanical performances of PEC columns exposed to standard ISO-834 fire from four sides. The calculated deformation curves and fire resistance of PEC columns were validated by the test results.Based on the validated model,influences of related parameters,such as sectional dimensions,load ratio,slenderness ratio,steel ratio,load eccentricity ratio,strength of steel,strength of concrete and spacing of bars on fire resistance were ananlyzed. Conclusions are as follows:the main influencing parameters are sectional dimensions,load ratio,slenderness ratio;steel ratio,load eccentricity ratio,strength of steel,strength of concrete and spacing of bars are minor factors.Based on the parametric analysis,the simplified formulas for the calculation of the fire resistance was put forward. The calculating results are in good agreement with that of numerical method.The achievements in this paper may be a reference for the fire design of PEC Columns.更多还原