Performance evaluation of structural concrete with innovative reinforcement solutions

新型混凝土和钢筋为创新的结构设计创造了机会;然而，它们也为我们理解安全设计的行为和方法带来了挑战。拟议的研究解决了现代结构混凝土的分析和设计的一个关键问题，具有创新的解决方案。 具体而言，在这项拟议的工作中，两种类型的混凝土构件进行了调查：平板支撑柱，和完全或部分使用纤维增强塑料（FRP）钢筋加固的构件。混凝土板并不是什么新鲜事，但冲切问题仍然有许多尚未解决的设计问题。FRP加固构件的行为根据不同的原则比传统的钢筋构件;他们依靠混凝土提供峰值后的延性。因此，不同的规范和设计指南之间的设计方法存在差异，这两种类型的结构。 将研究柱上的混凝土平板及其在静态和地震荷载下的冲切性能。冲剪破坏是脆性破坏，是一种危险的破坏形式，可导致建筑物的连续倒塌。试验将在具有不同抗剪加固方案的预应力板上进行。将测试混合FRP和纤维增强混凝土（FRC）平板作为安大略结构和桥梁耐腐蚀系统的适用性。有限元软件Abaqus中的损伤塑性有限元（FE）模型将用于混凝土和钢筋性能、位置、板连续性、开口、不平衡力矩和支撑几何形状对冲切强度影响的参数研究。不同的实践规范对板的抗剪设计方法不同，都采用经验公式。一个新的fib组WP 4.3.2已经成立，为规范的制定提供指导，并促进板中冲切设计的合理力学方法（申请人是受邀成员）。 对混凝土中FRP筋的研究将集中在钢筋和用它们加固的构件的质量上。由于安大略的腐蚀问题，现在经常考虑FRP加固（例如，MTO）作为钢的替代品;但它们的长期性能和设计尚未得到充分理解和开发。工作将涉及非线性有限元分析研究，压杆和拉杆建模，以及用FRP筋加固弯曲和剪切构件的实验程序。钢筋的位置，剪切钢筋形状，混凝土和梁的几何形状的影响将得到解决。利用纤维增强混凝土（FRC）与FRP加固的可能性也将进行实验和数值研究。 上述研究步骤非常适合在加拿大为工业界和学术界培养急需的HQP。

New types of concretes and reinforcements create opportunities for innovative structural designs; however, they also create challenges in our understanding of behaviour and methods of safe designs. The proposed research addresses a crucial issue of the analysis and design of modern structural concrete with innovative solutions for reinforcements. Specifically in this proposed work, two types of concrete members are investigated: flat slabs supported on columns, and members reinforced fully or partially using fibre reinforced plastic (FRP) reinforcements. Concrete slabs are not new, but the issue of punching shear still has many unresolved design questions. FRP reinforced members behave according to different principles than traditional steel reinforced members; they rely on concrete to provide post peak ductility. Consequently, discrepancies exist in the design approaches among different codes and design guidelines for both types of these structures. Flat concrete slabs on columns and their punching shear behaviour in both static and seismic load scenarios will be studied. Punching shear failures are brittle and dangerous and can lead to progressive collapses of buildings. Testing will be done on prestressed slabs with different shear reinforcing solutions. A hybrid FRP and fibre reinforced concrete (FRC) flat slabs will be tested for their applicability as corrosion resistance systems for Ontario structures and bridges. The damaged plasticity finite element (FE) model within the FE software Abaqus will be used for parametric studies on the effects of concrete and reinforcement properties, placement, slab continuity, openings, unbalanced moments, and support geometry on the punching shear strength. Different codes of practice approach the shear design of slabs differently; all with empirical formulas. A new fib group WP 4.3.2 has been formed to provide guidelines for code developments and to promote a rational mechanics-based approach to punching shear design in slabs (the applicant is an invited member). Research on FRP reinforcements in concrete will concentrate on the quality of the reinforcements and of the members reinforced with them. Due to corrosion problems in Ontario, FRP reinforcements are now often considered (e.g., MTO) as a replacement for steel; yet their long-term properties and designs are not fully understood and developed. Work will involve nonlinear FEA studies, strut-and tie modelling, and experimental programs with members reinforced with FRP bars for both flexure and shear. The effects of rebar placement, shear-reinforcement shapes, concrete, and beam geometry will be addressed. The possibility of utilizing fibre reinforced concretes (FRC) with FRP reinforcements will also be investigated both experimentally and numerically. All of the above research steps are very fitting for the training of much needed HQP in Canada for both industry and academia.