【作者】 赵天石；

【导师】 王钧；

【作者基本信息】 东北林业大学 ， 结构工程， 2010， 硕士

【摘要】 我国的建筑工程已由“新建为主”逐渐过渡到“新建与改建并重”的阶段。对既有房屋套建增层改造已成为当今土木工程界的热点之一。由于普遍要求套建增层时,既有房屋须维持正常运营,这就要求在套建结构设计及施工过程中避免将增层的荷载传给既有房屋的屋盖。预应力混凝土技术是对混凝土结构的技术革命。用现代概念和方法设计的高效预应力混凝土,可以有效的改善结构使用阶段性能(如控制裂缝开展和消除结构挠度等),提高受剪承载力和疲劳强度,改善受荷后的恢复力性能,充分利用高强度钢材,有效调整结构内力等。内置H型钢混凝土组合结构是实现套建增层的结构设计形式之一。内置H型钢预应力混凝土组合梁是指在型钢上、下翼缘之间合理布置并张拉一定数量的预应力筋，在型钢外围绑扎非预应力钢筋骨架并浇筑混凝土而形成的由混凝土、型钢、预应力筋及非预应力钢筋骨架组合而成的梁。这类梁兼具钢梁与混凝土梁的双重优点,有广阔的应用空间。在充分查阅了大量的参考文献后,了解了型钢混凝土结构在国内外的研究现状,对比了预应力型钢混凝土的结构特点,明确了其研究及应用价值。这种结构形式可以更好地完成大跨、重载条件下的受力性能。内置H型钢预应力混凝土组合梁在工程中常出现小剪跨比受剪情况,这类构件的受剪性能研究尚未见报导。本文从受剪理论出发,分析了钢筋混凝土、预应力钢筋混凝土、型钢混凝土及预应力型钢混凝土组合构件的受剪机理、斜截面的主要破坏形式以及剪跨比、混凝土强度等级等关键参数对截面承载力的影响。针对问题完成了5根这类简支梁小剪跨比的受剪试验,积累了试验数据。基于这类梁的抗剪试验及机理分析,考察了加载条件下的变形发展情况,提出了这类梁的受剪承载力公式。更多还原

【Abstract】 It has a gradual transition to a new phase of equal importance with new-built and reconstruction compared with new-built mainly before of construction engineering in our country.The reconstruction technique using outer-jacketing structure for adding storie around the existing building has become one of the hot issues of civil engineering. The existing building need works as usual which requried to avoid the added load transferred to the roof of the existing building during reconstructure.Prestressed concrete technology is a technological revolution to concrete structure.High efficient prestressed concrete which designed by modern concepts and methods, can effectively improve the structure performance of using stage (such as controlling development of crack and eliminating deflection of structure, etc.), raise the shear and fatigue strength, improve resilience after load, make full use of high strength steel and adjust internal force of structure effectively. Prestressed composite concrete beam with encased H-steel is one of the structural design forms for the outer-jacketing structure for adding story.Prestressed composite concrete beam with encased H-steel is constituted with the skeleton combination of concrete,steel,prestressed tendons and non-prestressed reinforcement. A number of prestressed tendons are arranged rationally between the upper and lower flange of the steel. And lash non-prestressed reinforcement frame in the steel periphery and poured concrete.Such beams has both advantages of the steel beam and concrete beam,and there is a broad application space. After read a large number of references, we understand the research of concrete structures encased steel at home and abroad, compared the structural characteristics of prestressed concrete encased steel, clear of the value of the research and application. This structure is better for the conditions of the performance which is large-span, and heavy force.It often appear small shear span ratio of shear in the engineering of prestressed concrete composite beams encased steel. Research of these components has not been reported. In this paper,base on the shear theory,we analysis the shear mechanism of reinforced concrete,prestressed reinforced concrete, concrete encased steel and prestressed concrete composite member encased steel. Discussed the main damage form of oblique section and the influence on section bearing capacity which originated from key parameters such as shear span ratio and concrete strength grade.In order to solve these problems the we completed shear tests of five simple beams with small shear span ratio, and accumulated test data.Based on shear tests of these beams and mechanism analysis, we studied the development of deformation under load and made the shear strength formula of these beams.更多还原