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，但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。这项拟议的研究解决了现代结构混凝土的分析和设计以及钢筋的创新解决方案这一关键问题。*在这项拟议的工作中，具体研究了两种类型的混凝土构件：柱上支承的平板和完全或部分使用纤维增强塑料(FRP)加固的构件。混凝土板并不新鲜，但冲切问题仍然有许多悬而未决的设计问题。FRP加固构件的工作原理与传统的钢筋加固构件不同；它们依靠混凝土来提供高峰期后的延性。因此，对于这两种结构，不同的规范和设计指南在设计方法上存在差异。*柱上的混凝土扁板及其在静力和地震荷载情况下的冲切性能将被研究。冲切破坏是脆弱和危险的，可能会导致建筑物的渐进性倒塌。试验将在预应力板上进行，采用不同的抗剪加固方案。将测试一种FRP和纤维增强混凝土(FRC)混合平板作为安大略省结构和桥梁防腐系统的适用性。有限元软件ABAQUS中的损伤塑性有限元(FE)模型将用于参数研究混凝土和钢筋特性、放置、板的连续性、开孔、不平衡力矩和支撑几何形状对冲切剪切强度的影响。不同的实用规范采用不同的方法进行楼板的抗剪设计；均采用经验公式。已经成立了一个新的FIB小组WP 4.3.2，以提供规范开发的指导方针，并促进基于合理力学的方法来进行板的冲切设计(申请人是受邀成员)。*关于混凝土中FRP加固的研究将集中在钢筋及其加固构件的质量上。由于安大略省的腐蚀问题，玻璃钢加固材料现在通常被认为是钢材的替代品(例如，MTO)；然而，他们的长期性能和设计还没有得到充分的了解和开发。工作将包括非线性有限元研究，压杆和拉杆模型，以及用FRP筋加固受弯和受剪构件的实验计划。将讨论钢筋放置、剪力钢筋形状、混凝土和梁几何形状的影响。还将从试验和数值两个方面研究纤维混凝土(FRC)与FRP加固的可能性。*所有上述研究步骤都非常适合在加拿大为工业界和学术界培训急需的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. *****