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为可持续和有弹性的结构引入新技术和材料来担任负责任的环境管理员，这些新技术和材料有助于保护我们的资源，同时减少建筑的碳足迹。根据加拿大国家气候变化政策，未来几年，通过征收碳税或建立可交易的碳排放许可制度，水泥成本将大幅上升。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)，通过用粉煤灰部分取代波特兰水泥来增加可持续性。HPFRCC是一种相对较新的创新材料，与传统混凝土相比，它能够抵抗较大的拉力和剪力，表现出直接拉伸时的应变硬化、更高的韧性和延性、裂缝控制、在动态影响下增强性能以及更高的能量吸收能力。尽管HPFRCC的力学性能已经被研究并得到了较好的记录，但需要进行研究来开发模型和建立设计指南，以使HPFRCC能够在关键基础设施中大规模使用。由于平板具有许多优点，在许多多层建筑中得到了广泛的应用，但它们很容易受到冲切破坏。在这项研究中，将考虑一种新型的高性能混凝土，并对板柱节点的冲切性能进行研究。拟议的研究计划将考虑将节点处的HPFRCC作为冲切钢筋的替代方案。本文将首先对HPFRCC的力学性能进行评估，然后对新型板柱节点进行冲切试验研究。在HPFRCC板中，将考虑钢筋配筋率的降低带来的好处，从而减少腐蚀风险，从而检查抗弯配筋率的影响。同时，考虑重力诱导剪切对转角和漂移能力的影响，对拟建的HPFRCC板的抗震性能进行了研究。最后，采用先进的非线性有限元分析方法(FEA)对试验的高强混凝土板进行了分析，考虑了现有的和新发展的塑性损伤模型。将对混凝土性能、钢筋性能和放置、不平衡弯矩和支撑几何形状对混凝土平板冲切剪切强度的影响进行参数研究。该研究计划旨在通过学徒、指导和接触令人兴奋和严谨的研究环境相结合的方式，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.