Calculation of corrosion rate for reinforced concrete beams based on corrosive crack width

研究目的:为了解决不均匀锈蚀情况下钢筋锈蚀率的计算问题,实现锈胀开裂构件的锈蚀率无损检测,采用理论分析和试验研究相结合的方法,建立锈蚀梁钢筋最大锈蚀率的计算模型。创新要点:考虑了邻近位置混凝土开裂的影响,基于理论分析建立了不同位置的锈胀裂缝宽度修正模型。研究方法:首先通过理论分析建立考虑相邻测点相互影响的锈胀裂缝宽度修正模型,然后根据锈蚀物体积膨胀几何模型,建立基于锈胀裂缝宽度的锈蚀率计算公式,最后通过七根锈蚀梁的加速锈蚀试验验证了模型的准确性。重要结论:根据对开裂后钢筋与锈蚀物膨胀体积的量化分析,锈胀裂缝宽度与钢筋锈蚀率近似呈线性变化。电解液加速腐蚀试验结果表明,提出的锈蚀率计算方法得到的最大锈蚀率与实际平均值的比值在1.4–2.4之间,与实际情况符合较好。

Application of Back Analysis on Laterally Loaded Single Pile

In views of the limitations of the existing methods for calculating the pile foundation capacity, a back analysis approach of the m-value is introduced. In order to consider the sensitivity of pile behavior to the m-value,the relationships between the applied horizontal loads at pile head and the corresponding m-value along with the pile stiffness changes are studied. Based on statistics data from the extensive in-situ tests, the back analysis results suggest an exponential expression for the m-value in various soil conditions and horizontal displacements at pile head. This method is capable of providing an accurate m-value in calculating the pile responses under lateral loads.