Performance evaluation of High-Performance Fibre-Reinforced Cementitious Composite slab-column connections

随着全球建筑业的不断加速增长，结构工程师可以通过引入新技术和材料来实现可持续和有弹性的结构，从而成为负责任的环境管理者，帮助保护我们的资源，同时减少建筑的碳足迹。根据加拿大国家气候变化政策，通过碳税或可交易碳排放许可证制度，未来几年水泥成本将大幅增加。为了减少水泥产量，一个潜在的解决方案是在结构中使用高性能纤维增强水泥复合材料 (HPFRCC)，通过用粉煤灰部分替代波特兰水泥来提高可持续性。 HPFRCC 是相对较新的创新材料，可抵抗大的拉伸和剪切力，与传统混凝土相比，在直接拉伸下表现出应变硬化、增强的韧性和延展性、裂缝控制、增强的动态效应性能以及高能量吸收能力。尽管 HPFRCC 的机械性能已得到研究并有相对完善的记录，但仍需要进行研究来开发模型并建立设计指南，以便能够在关键基础设施中大规模使用 HPFRCC。由于平板具有许多优点，因此广泛应用于许多多层建筑中，但它们很容易受到冲剪破坏。在本研究项目中，将考虑一种新型 HPFRCC，并对板柱连接的冲剪性能进行研究。拟议的研究计划将考虑连接处的 HPFRCC 作为冲切钢筋的替代方案。这项工作将首先评估 HPFRCC 的机械性能，然后对新型板柱连接中的冲剪进行实验研究。在 HPFRCC 板中，将检查弯曲配筋率的影响，考虑钢筋的潜在减少，从而因腐蚀风险降低而带来好处。同时，考虑重力引起的剪切对旋转和漂移能力的影响，将检查拟议的 HPFRCC 板的抗震性能。最后，将使用先进的非线性有限元分析 (FEA) 对测试的 HPFRCC 板进行分析，其中将考虑当前和新开发的塑性损坏模型。将进行混凝土性能、钢筋性能和布置、不平衡力矩和支撑几何形状对混凝土平板冲剪强度影响的参数研究。该研究计划旨在通过学徒、指导和接触令人兴奋和严格的研究环境相结合，在五年内培养和激励高素质人才 (HQP) 的培训。

As the growth of global construction keeps accelerating, structural engineers can serve as responsible stewards of the environment by introducing new technologies and materials for sustainable and resilient structures that help to preserve our resources while reducing the carbon foot print of construction. Based on the Canadian National Climate Change Policy, the cost of cement will increase dramatically in the coming years through carbon tax or a system of tradeable carbon emissions permits. In order to reduce cement production, a potential solution is to use High-Performance Fibre-Reinforced Cementitious Composites (HPFRCCs) in structures to increase sustainability through partial replacement of Portland Cement with fly ash. HPFRCCs are relatively new and innovative materials that resist large tensile and shear forces showing strain hardening in direct tension, increased toughness and ductility, crack control, enhanced performance in case of dynamic effects, and high-energy absorption capacity when compared to conventional concrete. Whereas the mechanical properties of HPFRCCs have been studied and are relatively well documented, research is required to develop models and establish design guidelines to enable large scale HPFRCC use in critical infrastructure. Flat slabs are widely used in many multistory buildings because of the many advantages that they provide, however, they are susceptible to punching shear failure. In this research program, a novel HPFRCC will be considered and the punching shear behaviour of slab-column connections will be investigated. The proposed research program will consider HPFRCC at the connections as an alternative for punching shear reinforcement. This work will first evaluate the mechanical properties of HPFRCC and then undertake an experimental investigation of punching shear in novel slab-column connections. In HPFRCC slabs the effect of the flexural reinforcement ratio will be examined considering potential reductions in steel reinforcement leading to benefits due to the reduced risk of corrosion. At the same time, the seismic performance of the proposed HPFRCC slabs will be examined considering the effect of gravity-induced shear on the rotation and drift capacity. Finally, the tested HPFRCC slabs will be analyzed using advanced nonlinear finite element analysis (FEA), where current and newly developed plasticity-damaged models will be considered. Parametric studies on the effects of concrete properties, reinforcement properties and placement, unbalanced moments, and support geometry on the punching shear strength of flat concrete slabs will be undertaken. This research program is designed to foster and inspire the training of highly qualified personnel (HQP) over a five year period through a combination of apprenticeship, mentorship and exposure to an exciting and rigorous research environment.