Dey Alinda, Vastrad Akshay Vijay, Bado Mattia Francesco, Sokolov Aleksandr, Kaklauskas Gintaris
Department of Reinforced Concrete Structures and Geotechnics, Vilnius Tech University (VGTU), Saulatekio al. 11, 10221 Vilnius, Lithuania.
Department of Civil and Environmental Engineering, Technical University of Catalonia (UPC), c/Jordi Girona 1-3, 08034 Barcelona, Spain.
Materials (Basel). 2021 Jan 6;14(2):254. doi: 10.3390/ma14020254.
The contribution of concrete to the tensile stiffness (tension stiffening) of a reinforced concrete (RC) member is a key governing factor for structural serviceability analyses. However, among the current tension stiffening models, few consider the effect brought forth by concrete shrinkage, and none studies take account of the effect for very long-term shrinkage. The present work intends to tackle this exact issue by testing multiple RC tensile elements (with different bar diameters and reinforcement ratios) after a five-year shrinking time period. The experimental deformative and tension stiffening responses were subjected to a mathematical process of shrinkage removal aimed at assessing its effect on the former. The results showed shrinkage distinctly lowered the cracking load of the RC members and caused an apparent tension stiffening reduction. Furthermore, both of these effects were exacerbated in the members with higher reinforcement ratios. The experimental and shrinkage-free behaviors of the RC elements were finally compared to the values predicted by the CEB-fib Model Code 2010 and the Euro Code 2. Interestingly, as a consequence of the long-term shrinkage, the codes expressed a smaller relative error when compared to the shrinkage-free curves versus the experimental ones.
混凝土对钢筋混凝土（RC）构件拉伸刚度（拉伸强化）的贡献是结构适用性分析的关键控制因素。然而，在当前的拉伸强化模型中，很少有模型考虑混凝土收缩带来的影响，而且没有研究考虑长期收缩的影响。本研究旨在通过对多个RC受拉构件（具有不同的钢筋直径和配筋率）在经历五年收缩期后进行试验来解决这一确切问题。对试验得到的变形和拉伸强化响应进行了消除收缩的数学处理，以评估其对前者的影响。结果表明，收缩明显降低了RC构件的开裂荷载，并导致明显的拉伸强化降低。此外，在配筋率较高的构件中，这两种影响都更加明显。最后将RC构件的试验结果和无收缩性能与CEB-fib 2010模型规范和欧洲规范2预测的值进行了比较。有趣的是，由于长期收缩，与无收缩曲线相比，规范与试验曲线相比表现出较小的相对误差。
