不同剪跨比下陶粒混凝土叠浇梁抗剪性能试验研究

简支梁受压区采用普通混凝土, 受拉区采用陶粒混凝土, 可充分利用普通混凝土的高抗压强度及陶粒混凝土良好延性及自重轻的优点, 实现二者有机结合. 通过设计制作3根底部采用陶粒混凝土, 上部采用普通混凝土, 剪跨比分别为1.3、1.9、2.5的叠浇梁, 和1根剪跨比为1.9的全陶粒混凝土梁进行抗剪性能试验, 分析叠浇梁在荷载作用下的整体工作性能与破坏特征, 研究不同剪跨比对叠浇梁抗剪极限承载力、变形、最大斜裂缝宽度、纵筋应变和箍筋应变的影响. 结果表明: 所设计的叠浇梁叠浇结合面整体工作性能良好; 随着剪跨比的增大, 跨中挠度和最大斜裂缝宽度增大; 达到极限荷载时, 纵筋均未屈服, 剪跨区箍筋屈服, 4根简支梁均发生典型的剪切破坏.

Shear performance of the ceramsite aggregate concrete stack poured beam with variant shear span ratios

The compressive zone uses normal strength concrete and the tensile zone uses ceramsite aggregate concrete. The combination of these two types of concrete takes advantages of the high compressive strength of the high normal strength concrete and the light weight as well as high ductility of the ceramsite concrete. To examine the overall working performance and failure characteristics of the stack poured beam under load, we build a whole ceramsite aggregate concrete beam with a shear span ratio of 1.9 and use ceramsite aggregate concrete at bottom and ordinary concrete at top to stack-pour three simple-supported beams with shear span ratios of 1.3, 1.9, and 2.5, respectively. We have also conducted the study on the effect of variant shear span ratio on the shear strength, deformation, maximum diagonal crack, longitudinal reinforcement, and stirrup strain. Results show that the overall working performance of the designed stack poured beam is satisfying; the midspan deflection and the maximum diagonal crack increase with the increase of the shear span ratio. When the ultimate bearing capacity is reached, part of the stirrup yields while the longitudinal reinforcement does not. The four beams undergo a typical shear failure but maintain overall integrity.