Experimental / Theoretical Study on Strengthening effect enhancements of RC Structures with Hybrid FRP Laminates

混合 FRP 层合板增强 RC 结构加固效果的实验/理论研究

基本信息

批准号：
13650501
负责人：
WU Zhishen
金额：
$ 2.11万
依托单位：
IBARAKI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650501/
关键词：
Fiber reinforced polymer (FRP)Hybrid Relieving of stress concentration Flexural strengthening Debonding Fracture mechanics Finite element analysis Optimum and integrated design

项目摘要

(1) Basic Hybrid Design of Different Fiber SheetsThe needs, requirements and points at issue on hybrid laminates by hybridizing different fibers are cleared up through investigating different design indices such as initial stiffness, rupture strength, ultimate strength and ductility and control indices such as strain hardening characteristics and stress drop due to successive fiber rupture. Based on these achievements, the design methods of hybrid FRP laminates by using different fibers such as three types of carbon fiber sheets with superhigh modulus, high modulus and high strength, two types of aramid fiber sheets with different moduli, PBO fiber sheet and glass fiber sheet with high rupture strain are proposed for different purposes. Moreover, the corresponding design program is also coded.(2) Experimental and Theoretical Investigations on Believing of Stress Concentrations due to Fiber Rupturing ImpactsIn order to improve above basic hybrid design, an analysis is performed to inves … More tigate how to relieve the stress concentrations induced by successive rupture of fibers. In addition, some tension tests were conducted to demonstrate the effect of PBO fibers with higher ability of energy absorption for relieving stress concentrations.(3) Experimental and Numerical Investigations on Strengthening Effects in Compressive and Flexural Concrete Members Strengthened with Hybrid Fiber SheetsThe designed hybrid fiber sheets are used to flexurally strengthen plain and reinforced concrete beams and the corresponding strengthening effects are qualitatively evaluated in terms of stiffness, strength, ductility and crack resistance. In addition, a series of concrete cylinder specimens wrapped with the proposed hybrid fiber sheets is used to investigate the confinement effects through varying different variables such as reinforcing ratios (spacing of wrapped fiber sheet strips) and concrete strength, etc.(4) Investigations on Interfacial Bond Behavior and Failure Mechanism along FRP and Concrete interfaceFirst, analytical equations are derived for predicting the bond carrying capacity in RC prisms bonded with FRP sheets. Based on a lot of experimental observations, both analytical and numerical analyzes are performed to give a clear insight into the bonding and debonding mechanisms in RC flexural members strengthened with different hybrid FRP sheets.(5) Establishments of Design Method and FE ModelThrough above analytical and numerical investigations, an existing analytical approach for predicting interfacial debonding failure is modified for evaluating the debonding behavior of strengthened structures with hybrid fiber sheets. A comprehensive design guideline is then developed to include all the possible failure modes such as steel yielding-FRP rupture, concrete crushing, shear failure and various debonding failures. Moreover, a constitutive model is established on the basis of experimental results to simulate the progressive rupture of fibers in hybrid fiber sheets and thus a nonlinear FE analysis can be implemented to evaluate both failure progresses caused by progressive rupture of fibers and cracking of concrete.(6) Optimum and integrated Design of RC Structures strengthened with Hybrid Fiber SheetsTo further develop the hybrid design concept, a series of experimental and numerical investigations is conducted to discuss countermeasures of realizing structural integrity of strengthened structures on different structural performances such as the initial stiffness, yield and ultimate loads and structural ductility under controlled load drops caused by progressive fiber ruptures. Through these investigations, an optimum design method on structures strengthened with hybrid FRP sheets is also proposed. Less

（1）不同纤维的基本杂种设计需要研究设计的初始刚度，碎石强度，终极强度和延展性和控制，例如由于连续的纤维破裂而引起的应变硬化和压力。具有超高模量，高强度和高强度的碳纤维纤维，两种具有不同模纤维，PBO纤维和玻璃纤维的芳族纤维纸，提出了高度破裂的菌株，以进行弥漫性设计。进行分析以进行研究……更多地通过纤维破裂释放压力收缩。实验性和数值。 S用于通过变化的变量来研究限制，例如增强比率D具体强度等。（4）沿FRP和混凝土界面的界面键行为为界键行为为be be，以预测与FRP牌键合的RC PRISM中的键容量。基于许多经验观测和数值分析，可以使Anto在RC挠性膜中的结合和Depondhanism withent Hybr ID frp she，以预测界面剥离失败然后，开发了钢制破裂模式，钢制破裂，剪切失败和各种g失败。评估由纤维的进行性碎石和混凝土的破裂引起的，而混合纤维板的综合设计进一步发展了混合设计概念L和数值投资，以讨论实现诸如不同ral表现的陌生结构的结构完整性。最初的刚度，产量和最终的污垢，由imum ruptores引起的载荷量也较少。