反复荷载下钢-聚丙烯混杂纤维混凝土粘结性能与节点抗震性能研究

With reference to the previous study by other researchers , the following research associated with the steel-polypropylene hybrid fiber reinforced concrete (SPHFRC) is to be carried out in this proposal: taking the factors such as the characteristic parameters of fiber and the properties of concrete and steel reinforcement into account, the bond mechanism and its degradation of the SPHFRC is explored based on the test under axial reversal loading and the damage theory; the loading process and damage pattern of the SPHFRC joint is observed through the pseudo-static test under reversal loading and the seismic performance of the SPHFRC joint is investigated; based on the previous study, the mechanical behavior and damage pattern of the RC frame employing the SPHFRC joint is studied by way of shake-table test, theoretical analysis and numerical simulation, and the fulfillment strategy of beam-hinge mechanism is discussed. The following research outcomes are to be expected: (1) setting up the bond stress vs. slip displacement relationship of the SPHFRC under reversal loading;(2) establishing the hysteresis model of the SPHFRC joint; (3) deriving the calculation formula of shear bearing capacity of the SPHFRC joint under reversal loading;(4) proposing the method of fulfilling the philosophy of "strong column and weak beam" for the RC frame with the SPHFRC joint. The research results in this proposal are aimed to promote the application of hybrid fiber reinforced concrete and provide the theoretical support and experimental basis for complement and perfection of the related provisions in "Technical specification for fiber reinforced concrete structure"(CECS38:2004).

借鉴前人的研究成果，考虑纤维特征参数、混凝土与钢筋的材性等影响因素，通过拉压反复荷载试验，运用损伤理论，探讨钢-聚丙烯混杂纤维混凝土的粘结机理及退化规律；通过拟静力试验考察反复荷载下混杂纤维增强混凝土框架节点的受力过程、破坏形态等，研究其抗震性能；在此基础上，通过振动台试验、理论分析和有限元仿真，研究混杂纤维增强混凝土节点的框架结构在地震模拟荷载下的受力性能、破坏机理，探讨梁铰机制的实现，提出如下预期成果：（1）建立反复荷载下钢-聚丙烯混杂纤维混凝土粘结应力-滑移本构模型；（2）建立钢-聚丙烯混杂纤维混凝土节点的恢复力模型；（3）提出反复荷载下钢-聚丙烯混杂纤维混凝土节点抗剪承载力计算公式；（4）提出钢-聚丙烯混杂纤维增强混凝土节点的框架结构"强柱弱梁"的实现方法。研究成果将促进混杂纤维混凝土的工程应用，为补充和完善《纤维混凝土结构技术规程》(CECS38:2004)的有关条文提供理论依据

随着混凝土技术的快速发展，纤维混凝土由于其优越的抗拉性能、耗能能力以及抗裂能力，在工程实践中的应用已经得到了业界广泛的认可。在建筑结构中的一些关键部位使用纤维混凝土（如梁柱节点、柱端、跨中梁底等）来防止结构的过早破坏，已经被视为一种非常有前途的方法。考虑到裂缝在混凝土中的发展特征，掺入两种或多种不同的纤维形成一个混杂体系，从而从不同尺度、不同阶段来抑制裂缝的萌生扩展是更为有效的。因此，本项目以应用最为广泛的钢-聚丙烯混杂纤维混凝土为研究对象，在借鉴前人研究成果的基础上，考虑纤维特征参数、混凝土与钢筋的材性等影响因素，通过拉压反复荷载试验，运用损伤理论，探讨了钢-聚丙烯混杂纤维混凝土的粘结机理及其退化； 通过拟静力试验考察了反复荷载下混杂纤维增强混凝土框架节点的受力过程、破坏形态等，研究其抗震性能；并在此基础上，通过理论分析和有限元仿真，研究了混杂纤维增强混凝土节点的框架结构在地震模拟荷载下的受力性能、破坏机制，探讨梁铰机制的实现。研究成果如下：（1）建立了反复荷载下钢-聚丙烯混杂纤维混凝土粘结-滑移本构模型；（2）建立了反复荷载下钢-聚丙烯混杂纤维混凝土节点的恢复力模型；（3）提出了钢-聚丙烯混杂纤维混凝土节点抗剪承载力计算公式；（4）提出了钢-聚丙烯混杂纤维增强混凝土节点的框架结构“强柱弱梁”的实现方法。研究成果能够有效地预测混杂纤维混凝土在反复荷载作用情况下的粘结响应和节点抗震性能，为补充和完善《纤维混凝土结构技术规程》(CECS38:2004)的有关条文提供理论依据，促进混杂纤维混凝土的工程应用。