木-轻集料混凝土组合梁弯曲变形特性研究  

RESEARCH ON THE DEFORMATION CHARACTERISTICS OF WOOD-LIGHTWEIGHT AGGREGATE CONCRETE COMPOSITE BEAMS

作　　者：胡亚风[1] 魏洋[1] 赵龙龙[1] HU Yafeng;WEI Yang;ZHAO Longlong(College of Civil Engineering,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]南京林业大学土木工程学院

出　　处：《工业建筑》2019年第10期117-122,共6页Industrial Construction

基　　金：国家自然科学基金项目(51208262);江苏省自然科学基金(BK20151520);江苏省“333”工程(BRA2016421)和“青蓝工程”项目;江苏高校优势学科建设工程资助项目(PAPD)

摘　　要：将5组螺栓植入到木梁及轻集料混凝土中制备成组合梁试件。对组合梁在三分点进行弯曲加载,对加载过程中界面的相对滑移、应变及跨中挠度等特性进行测量。制备的组合梁试件抗弯性能,包括抗弯承载力、界面相对滑移、跨中截面应变及挠度等,都与螺栓的直径及其分布间距有关。螺栓直径大或者其分布间距较小时,组合梁试件抗弯过程中表现出较小的界面相对滑移,较窄的应变范围和较小的跨中挠度。螺栓直径为8 mm且螺栓分布间距为200 mm的组合梁比螺栓直径为12 mm、分布间距为150 mm的组合梁的界面最大相对滑移提高2.8倍,截面最大应变提高3倍,跨中挠度提高2.2倍。试验表明:组合梁试件断裂部位集中在木梁上,轻集料混凝土板侧面未产生贯穿的裂纹、混凝土板顶面未被剪切破坏,亦未见螺栓被剧烈拔出等破坏现象,组合梁试件破坏模式属于延性失效;组合梁上木材与轻集料混凝土相对滑移沿着纵向整体分布规律一致,表明螺栓剪力键能较好地进行剪力传递。Five groups of bolts were implanted into wood beam and lightweight aggregate concrete to form composite beam specimens.The relative slip,strain and mid-span deflection of composite beams under four-point bending loading were studied experimentally.The flexural properties of the composite beam specimens,including the flexural capacity,the relative slip of the interface,the strain and deflection of the mid-span section,were all related to the diameter of the bolts and their distribution spacing.When the bolt diameter was large or its distribution spacing was small,the composite beam specimens showed a relatively low interface slip,narrow strain range and small mid-span deflection in the bending process.Particularly,the composite beam with bolt diameter of 8 mm and bolt spacing of 200 mm was 2.8 times higher than the composite beam with bolt diameter of 12 mm and bolt spacing of 150 mm,but the maximum cross-section strain was 3 times higher and the mid-span deflection was 2.2 times higher.The test results also showed that when the specimen was damaged,the composite beam broke on the part of wood beam,and there were no penetrating cracks on the side of the lightweight aggregate concrete slab,and no shear failure on the top of the slab other.The bolts were not pulled out violently during the failure process,so the failure mode of the composite beam was ductile failure.The relative slip of wood and lightweight aggregate concrete on the composite beam was consistent with the overall distribution regular along the longitudinal length,indicating that the bolt could better transfer shear force.

关 键 词：螺栓 木-轻集料混凝土 组合梁 四点弯曲 界面相对滑移 应变 挠度 

分 类 号：TU3[建筑科学—结构工程]