纤维增强塑料管约束混凝土本构模型试验研究

进行了玻璃纤维增强塑料（GFRP）管约束混凝土本构模型试验．试件分三种类型：GFRP管直接受压；GFRP管不直接受压；GFRP管不直接受压，管内壁涂油脂．试验得到了混凝土纵向及环向应力-应变曲线，GFRP纵向应变和环向应变沿纵向的分布及泊松比曲线．试验可见，GFRP壳体测得的应变可代表核心混凝土的应变．纵向及环向应力-应变曲线可用曲线-线性强化模拟．达到非约束混凝土峰值应力前，三种试件的应力-应变曲线相当接近；GFRP不直接受压试件的第二斜率比直接受压试件的第二斜率大，但极限应力比后者小．核心混凝土达极限状态的标志是环向纤维达到极限拉应变．极限泊松比约为1．0～1．4．GFI蹬壳体与核心混凝土界面间存在粘结应力．

Experimental Research on Constitutive Model of Fiber Reinforced Polymer Tube Confined Concrete

A constitutive model test on glass fiber reinforced polymer(GFRP) tube confined concrete was carried out.The specimens were classified into three types:the GFRP tube was subjected to compression directly;the GFRP tube was not subjected to compression directly;and the GFRP tube was not subjected to compression directly while inner face of the GFRP tube was pasted with oil.The experimental results include longitudinal and hoop stress-strain curves of concrete,the distribution of longitudinal and hoop strain in axial direction and Poisson's ratio.Rosults show that the strains measured from GFRP jacket can represent the one of core concrete reasonably.Furthermore the longitudinal and hoop stress-strain curves can be simulated by curve-stiffen linearity behavior.Whether the GFRP jacket is compressed directly or not,the stress-strain curve is quite aclose to each other before the stress of concrete reaches the unconfined concrete ultimate strength.The second slope of specimen encased by the uncompressed GFRP jacket is higher than that encased by compressed GFRP jacket whereas the ultimate stress is lower than the latter.In addition,once the hoop strain of the GFRP jacket is ruptured the core concrete will collapse immediately.The ultimate Poisson's ratio is approximately 1.0 to 1.4.There is bond stress between the GFRP and the core concrete.