型钢再生混凝土梁受剪性能试验及承载力计算

Shear Performance Test and Bearing Capacity Calculation of Steel Reinforced Recycled Coarse Aggregate Concrete Beam

为了研究型钢再生混凝土梁的受剪性能,以剪跨比、再生粗骨料取代率、混凝土强度等级为变化参数,设计了12个试件进行静力加载试验。通过试验观察了试件受力破坏过程及形态,获取其荷载-变形全过程曲线、极限承载力等数据,并分析了再生粗骨料取代率、剪跨比、混凝土强度等参数对试件受剪承载力的影响规律。在试验基础上,建立了型钢再生混凝土梁受剪承载力的拟合公式;分别采用国内外相关规范公式计算试件的受剪承载力,并与试验结果进行对比分析。结果表明:型钢再生混凝土梁根据剪跨比的不同,表现为剪切斜压破坏和剪切粘结破坏两种不同的形态;再生骨料取代率对试件的受剪承载力有不利影响,但影响不大,而剪跨比和混凝土强度则有较大影响;随着剪跨比的增大,试件的承载力显著降低;随着混凝土强度的提高,试件的承载力有一定的提高;拟合公式和《型钢混凝土组合结构技术规程》方法可适用于型钢再生混凝土梁的受剪承载力计算,而《钢骨混凝土结构设计规程》及日本规范方法计算结果小于试验值。

In order to reveal shear performance of steel reinforced recycled coarse aggregate concrete beam, taking the shear span ratio, replacement ratio of recycled coarse aggregate and concrete strength class as variable parameters, 12 specimens were designed for static test. Through this test, the whole mechanical process and failure patterns of specimens were observed; the ultimate bearing capacity and load-displacement curves were obtained. The influence of recycled coarse aggregate replacement ratio, shear span ratio and concrete strength on the shear performance of specimens were analyzed. Based on experimental data, a shear capacity fitting formula of steel reinforced recycled concrete beams was put forward. Shear strength of specimens was calculated by using correlative standard formulae at home and abroad, and compared with experimental results. Results show that depending on the ratio of shear span, steel reinforced recycled coarse aggregate concrete beams present two shear failure patterns： when shear span ratio is in range 1.0 to 1.4, the baroclinic shear failure appears, and when shear span ratio is 1.8, the shear bond failure appears. Recycled coarse aggregate replacement ratio adversely affects the shear capacity of specimens, but has little effect. Whereas, shear span ratio and concrete strength have a greater impact. Shear capacity of specimen decreased obviously with the increase of shear span ration. However, with the improvement of concrete strength, the bearing capacity of specimen has improved to some extent. The proposed fitting formula and code of JGJ138-- 2001 can be used to calculate the shear capacity of steel reinforced recycled aggregate concrete beams, but the calculation results based on codes of YB 9082--2006 and AIJ97 are less than experimental data.