Performance evaluation of structural concrete with innovative reinforcement solutions

新型混凝土和钢筋为创新结构设计创造了机会；然而，它们也给我们对安全设计的行为和方法的理解带来了挑战。提出的研究解决了现代结构混凝土分析和设计的一个关键问题，具有创新的解决方案。******具体来说，在这项提议的工作中，研究了两种类型的混凝土构件：支撑在柱子上的平板，以及完全或部分使用纤维增强塑料（FRP）增强的构件。混凝土板并不新鲜，但冲剪问题仍有许多未解决的设计问题。FRP加固构件与传统钢筋加固构件的受力原理不同；它们依靠混凝土来提供峰后延性。因此，对于这两种类型的结构，不同的规范和设计指南在设计方法上存在差异。******柱上的混凝土平板及其在静力和地震荷载情况下的冲剪行为将进行研究。冲剪破坏是脆弱和危险的，并可能导致建筑物的逐步倒塌。试验将在不同的剪力加固方案的预应力板上进行。混合FRP和纤维增强混凝土（FRC）平板将测试其作为安大略省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、放置、板连续性、开口、不平衡力矩和支撑几何形状对冲孔剪切强度的影响的参数化研究。不同规范对楼板抗剪设计的处理方法不同；都用经验公式。新的fib组WP 4.3.2已经形成，为规范开发提供指导方针，并促进基于合理力学的板冲剪设计方法（申请人是受邀成员）。*******对混凝土中FRP筋的研究将集中在FRP筋的质量和受其加固的构件的质量上。由于安大略的腐蚀问题，FRP增强材料现在经常被认为是钢的替代品（例如，MTO）；然而，它们的长期特性和设计还没有完全被理解和开发。工作将包括非线性有限元分析研究、杆系建模以及用FRP筋加固构件的抗弯和抗剪实验程序。钢筋放置、剪切钢筋形状、混凝土和梁几何形状的影响将被解决。利用纤维增强混凝土（FRC）与FRP增强的可能性也将进行实验和数值研究。******以上所有的研究步骤都非常适合加拿大工业界和学术界急需的HQP培训。* * * * *

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. *****