1东南大学混凝土及预应力混凝土结构教育部重点实验室，南京，210096；
2中国电子工程设计院，北京，100840。
【提要】 外包钢-混凝土组合梁是在由冷弯薄壁型钢与厚钢板焊接成的U型钢梁内浇注混凝土构件，并用必要的构造措施使型钢和混凝土共同工作。为研究这种新型组合梁的受力性能，完成了10根外包钢混凝土组合简支梁受弯试验。试验结果证明这种组合梁具有较优越的力学性能，但在受力过程中存在两个受力薄弱面，薄弱面的破坏会导致新型组合梁发生纵向水平剪切破坏和纵向滑移破坏，需在设计中避免。
【关键词】 组合梁 U型钢梁 滑移破坏 水平剪切破坏
Experimental Study on  Steel Encased Concrete Composite Beam/Du Derun1，Li Aiqun1，Chen Lihua1，Shi Qiyin1，Xiao Hui1，Lou Yu2，Li Peibin2 (1 Key Lab of RC & PC Structures Minister of Education PRC, Eastsouth University,Nanjing 210096,China; 2 China Electronics Engineering Design Institute, Beijing 100840，China)
Abstract:A newstyle steel encased concrete composite beam is presented. It is formed by
encasing the concrete into the Ushaped steel beam welded by coldformed sheets and a thick steel plate. The two parts cooperate with each other by indispensable constructional measure. Ten tests of the newstyle steel encased concrete composite simply supported beams had been performed to investigate the  mechanical performance. The test results show that the new style steel encased concrete composite beam has excellent mechanical performance. However, there are two shearoff planes, which would cause the longitudinal horizontal shear failure and the longitudinal slip failure of composite beams. The two failure modes must be avoided in design.
Keywords:composite beam; Ushaped steel beam; slip failure; horizontal shear failure
*《外包钢组合梁设计与施工规程》研究课题。