高强钢筋-混杂纤维超高性能混凝土结构受力机理及其设计理论研究

The ultra-high performance concrete is a promising new type of cement-based composites, characterized by its high strength, high toughness and high durability. The high strength steel bar can be used to replace middle strength steel bars. It is ideal for the development of a new type of high-strength steel bars reinforced ultra high performance concrete structures and highly effective prestressed structures, for the advancement of green development concept, thus promote structural safety and durability. This project researches on key science problems of high-strength steel reinforced ultra high performance concrete: how to use the high performance hybrid fibers to prepare the high toughness ultra-high performance concrete; flexural and shear behaviors and seismic performance of non-prestressed and pre-stressed ultra-high performance concrete beam. Based on modified compression field theory and plastic shear model, propose the flexural and shear strengths prediction model, considering the contribution of the hybrid fibers in tension and the diagonal crack interface. Research the compression performance of high strength stirrups constrained ultra-high-performance concrete columns, establishing failure criteria and stress-strain constitutive model. Study the shear and seismic performance of high-strength stirrups constrained ultra-high-performance concrete columns, propose the shear capacity model and the restoring force model, and set ductility-based seismic design method.

超高性能混凝土是一种很有发展前景的高性能水泥基复合材料，具有高强度、高韧性、高耐久性等显著特点，用高强钢筋代替中等强度钢筋，发展新型高强钢筋增强超高性能混凝土结构和高效预应力结构，符合绿色环保发展理念，对于提高结构安全性、耐久性具有重要意义。本项目研究高强钢筋-混杂纤维超高性能混凝土结构受力机理与设计理论，包括研究高性能混杂纤维超高性能混凝土增强韧性机理，预应力与非预应力超高性能混凝土梁抗弯、抗剪性能、破坏机制，充分考虑纤维在正截面受拉区贡献，建立抗弯承载力计算方法；基于压力场理论-塑性剪切理论，考虑纤维在斜截面的抗剪贡献，建立抗剪承载力计算理论；高强箍筋约束超高性能混凝土轴压特性、强约束下的破坏准则和应力-应变本构模型；高强箍筋约束超高性能混凝土柱的抗震性能，建立抗剪承载力模型、恢复力模型和基于延性的抗震设计方法等。

超高性能混凝土具有高强度、高韧性、高耐久性等显著特点，是目前最有发展前景的高性能水泥基复合材料。用高强钢筋代替中等强度钢筋，发展新型高强钢筋增强超高性能混凝土结构，对于提高结构安全性、耐久性具有重要意义。本项目研究了混杂纤维超高性能混凝土制备技术和微观机理，研究了混杂纤维超高性能混凝土增强韧性机理和韧性表征方法，研究了预应力与非预应力超高性能混凝土梁抗弯、抗剪性能、破坏机制，建立了抗弯承载力计算方法；基于压力场理论剪切理论，考虑纤维在斜截面的抗剪贡献，建立了抗剪承载力计算理论；开展了高强钢筋与超高性能混凝土的粘结性能试验和理论研究；完成了预应力超高性能混凝土梁正截面抗弯、斜截面抗剪性能和抗震性能的试验研究和理论分析；开展了超高性能混凝土连续梁弯矩调幅系数和梁正常使用性能的研究；试验研究了高强箍筋约束超高性能混凝土轴压特性，建立了超高性能混凝土轴压应力-应变本构模型；开展了基于修正压力场理论的超高性能钢纤维混凝土柱受剪承载力计算方法的研究，研究了高强FRP筋纤维增强高性能混凝土柱的抗震性能，建立抗剪承载力模型、恢复力模型和基于延性的抗震设计方法等；研究了混杂纤维增强超高性能混凝土加固混凝土梁抗弯性能及加固设计方法等。揭示了高强钢筋-混杂纤维超高性能混凝土结构受力机理，建立了结构计算理论和设计方法，为工程应用提供参考。