无腹筋混合配筋混凝土梁抗剪性能试验研究

Shear Behavior of Concrete Beams Reinforced with Hybrid (GFRP and Steel) Bars Without Stirrups

摘要:

对1组无腹筋混合配筋(GFRP筋(glass fiber reinforced polymer)和钢筋)混凝土梁抗剪性能进行了试验研究.所有试验梁均为三分点加载，剪跨比为2.54和2.67.12根试验梁按有效配筋率分为3组，共包括3根钢筋混凝土梁，3根GFRP筋梁和6根GFRP筋和钢筋混合配筋梁.所有试验梁均为斜拉破坏.分析了试验梁的荷载挠度关系，裂缝开展及抗剪承载力，并将各设计规范或指南的抗剪承载力预测值与试验结果对比.试验表明，有效配筋率相同的钢筋混凝土梁、混合配筋混凝土梁和GFRP筋梁具有相近的抗剪承载力.钢筋与FRP(fiber reinforced polymer)筋轴向刚度比对抗剪性能影响较小.规范Eurocode 2—04及CSA A23.3—04的抗剪承载力预测结果与试验结果符合度较好，而规范ACI440.1R—06,JSCE及CSAS6—06的预测结果偏保守.

Abstract:

This paper evaluates the shear behavior of hybrid GFRP/steel-reinforced concrete beams without transverse reinforcement.All beams were subjected to four-point loading,with shear span-to-effective depth ratio of 2.54 and 2.67 respectively.The test variables were effective reinforcement ratio and axial stiffness ratio between GFRP and steel bars.The test beams included three beams reinforced with steel bars,three beams reinforced with GFRP bars and six beams reinforced with GFRP and steel bars.An analysis was made of the load-midspan deflection curves,cracking behavior and shear strength of tested beams.The test results were compared with the predictions provided by different codes and design guidelines available.The test result shows that beams designed with the same effective reinforcement ratio,exhibits similar shear strength regardless of reinforcement arrangement (steel，GFRP，or combination of steel and GFRP).Axial stiffness ratio between GFRP and steel bars has little influence on shear behavior of hybrid GFRP/steel-reinforced concrete beams.Eurocode 2—04 and CSA A23.3—04 design method provids reasonable predictions,whereas the ACI440.1R—06,JSCE and CSA S6—06 results in conservative shear strength estimates.