ABSTRACT

The structural systems should maintain their strength, stiffness and ductility capacity under seismic effects. In reinforced concrete (RC) structures, the confinement effect provides these important features in the presence of the lateral reinforcements. Textile reinforced cementitious composites (TRCCs) have very good tensile, flexural and long-term performance. By using these multilayered composites as permanent formwork, the confinement effect can occur in RC columns. Moreover, thanks to the permanent formworks, the performance of RC structure will be increased during earthquake and service life will be extended against the drawbacks of structural defects. In this study, TRCC circular permanent formworks were produced by using a newly developed PPR (Pull-Pour-Roll) technique and machine. A cementitious mortar was designed and four and six layers of Ar glass (Alkali Resistant Glass) and four layers of basalt textiles were selected for the production of composite permanent formworks. The most important features of permanent formworks are hollow, thin section and three-dimensional structural elements. Five full-scale circular column specimens were tested in the laboratory under the combination of constant axial load and reversed cyclic lateral load. Three of the columns were constructed as permanent formwork, while others were reference specimens built by temporary formworks. All composite formwork columns and one of the reference specimens include insufficient lateral reinforcement. Whereas the other reference column has adequate lateral reinforcement. This study was carried out to evaluate the effect of TRCC permanent and conventional temporary formworks in RC columns on key parameters of confinement. These parameters are, respectively, the hysteretic response, strength, displacement ductility, stiffness degradation, energy absorption capacity, damping ratio, residual displacement, crack pattern and failure mechanism. The comprehensive experimental investigations have shown that TRCC permanent formwork improves confinement efficiency. Consequently, there is great potential for use of TRCC permanent formworks as an alternative for conventional formworks in the RC columns.

摘要

结构系统应在地震作用下保持其强度、刚度和延展性。在钢筋混凝土 (RC) 结构中，约束效应在横向钢筋存在的情况下提供了这些重要特征。纺织增强水泥基复合材料 (TRCC) 具有非常好的拉伸、弯曲和长期性能。通过使用这些多层复合材料作为永久性模板，可以在 RC 柱中产生约束效应。此外，由于采用了永久性模板，RC 结构在地震期间的性能将得到提高，使用寿命将得到延长，从而克服结构缺陷的弊端。在这项研究中，TRCC 圆形永久模板是通过使用新开发的 PPR（拉-浇-辊）技术和机器生产的。设计了一种水泥砂浆，并选择了四层和六层 Ar 玻璃（耐碱玻璃）和四层玄武岩纺织品来生产复合永久模板。永久性模板最重要的特征是空心、薄截面和三维结构元件。在恒定轴向载荷和反向循环横向载荷的组合下，在实验室中对五个全尺寸圆柱试件进行了测试。其中三根柱子是作为永久性模板建造的，而其他的则是用临时模板建造的参考样本。所有复合模板柱和一个参考样本的横向钢筋不足。而另一个参考柱具有足够的横向钢筋。本研究旨在评估 RC 柱中 TRCC 永久和常规临时模板对关键约束参数的影响。这些参数分别是滞后响应、强度、位移延性、刚度退化、能量吸收能力、阻尼比、残余位移、裂纹模式和失效机制。综合实验研究表明，TRCC 永久模板提高了约束效率。因此，使用 TRCC 永久模板替代 RC 柱中传统模板的潜力很大。阻尼比、残余位移、裂纹模式和失效机理。综合实验研究表明，TRCC 永久模板提高了约束效率。因此，使用 TRCC 永久模板替代 RC 柱中传统模板的潜力很大。阻尼比、残余位移、裂纹模式和失效机理。综合实验研究表明，TRCC 永久模板提高了约束效率。因此，使用 TRCC 永久模板替代 RC 柱中传统模板的潜力很大。