Satya Pranjal, Asai Tatsuya, Teshigawara Masaomi, Hibino Yo, Maruyama Ippei
Department of Environmental Engineering and Architecture, Graduate School of Environmental Studies, Nagoya University, Nagoya 464 8603, Japan.
Materials (Basel). 2021 Apr 10;14(8):1887. doi: 10.3390/ma14081887.
Evaluating the performance of reinforced concrete (RC) structures during earthquakes and the resultant damage in the structures depends on an accurate load-displacement relationship. Several experimental and analytical evaluation methods for load-displacement relationships have been proposed and specified in current design standards. However, there have been few quantitative studies on the impact of drying on the yielding behavior of RC members, including evaluations of the effective stiffness of members. In this study, to investigate changes in the mechanical properties of RC beam-slab members due to drying of the concrete, cyclic loading tests are conducted on two RC beam-slab members with and without drying. It is found that the lateral structural stiffness of the specimen with drying decreased to 77% that of the specimen without drying. This is verified in the calculation of the flexural stiffness. In this calculation, it is assumed that drying shrinkage decreases the moment of inertia of the slab in tension but not in compression. Meanwhile, no difference is observed in the flexural capacity and yield displacement between the two specimens. Thus, there is no significant impact from drying shrinkage in RC beam-slab members on the lateral structural performance, while the shrinkage instead induces greater flexural cracking, which reduces the residual stresses in the specimen with drift leading to a gradual decrease in the impact of drying.
评估钢筋混凝土（RC）结构在地震中的性能以及结构由此产生的损伤取决于精确的荷载-位移关系。目前的设计标准中已经提出并规定了几种用于荷载-位移关系的试验和分析评估方法。然而，关于干燥对RC构件屈服行为的影响，包括对构件有效刚度的评估，定量研究很少。在本研究中，为了研究混凝土干燥导致的RC梁板构件力学性能变化，对两个经过干燥和未经过干燥的RC梁板构件进行了循环加载试验。发现经过干燥的试件的横向结构刚度降低到未干燥试件的77%。这在抗弯刚度计算中得到了验证。在该计算中，假定干燥收缩会减小受拉区板的惯性矩，但不会减小受压区板的惯性矩。同时，两个试件在抗弯能力和屈服位移方面未观察到差异。因此，RC梁板构件中的干燥收缩对横向结构性能没有显著影响，而收缩反而会引发更大的弯曲裂缝，这会降低带有侧移试件中的残余应力，导致干燥影响逐渐减小。
