The Theoretical Analysis And Experimental Study Of CFRP Reinforced Steel Structure

Steel structure has high strength, light weight, good aseismic performance, high degree industrialization and repeatedly used etc, and is widely used in modern engineering structure form of structure. Due to the influence of various factors of manufacturing, construction, use and environment, steel structure inevitably exists all kinds of defects and damage.With the structure of the use of structure, material micro defects gradually expanded and rendezvous, causing materials in macroscopic mechanical properties of a place, even trigger engineering accident degradation. Therefore, studying how to prevent steel structure damage and how to reinforce and repair damage steel structure, has been in the field of civil engineering as an important content. The Carbon Fiber Reinforced Polymers (hereinafter referred to as the CFRP) strengthening and repairing the steel structure become a new reinforcement form and hot. Compared to the traditional metal structure reinforcement method, CFRP reinforced steel structure has many outstanding qualities technology, such as won't cause severe stress concentration, won't produce residual stress, construction is convenient, low maintenance fees. Therefore, CFRP reinforcement repair steel structure is a kind of high efficient and has wide prospect of reinforcement technology, involving material science, mechanical and structural engineering and other fields of knowledge.Currently the research and application of CFRP reinforced concrete structure technology relatively is more mature, but the research and application of CFRP reinforced metal structure technology is ont enough system and perfect. Based on the summarization about CFRP reinforcement and repairing of steel structure theory analysis and experimental research, this paper research the CFRP reinforcement repair steel structure of the specialty and the key problems in the system. Specific content as follows:Because of the big difference between CFRP metal structure inforcement and CFRP concrete structure inforcement, this paper firstly discussed the basic questions of CFRP reinforcement and repairing metal structure in detail, including bond mechanism, influencing factors of bond and the working mechanism after reinforcement of metal structure and potential failure mode of CFRP reinforced metal structure.This paper analysis axial tensile component interface stress and one-way shear component interface stress of CFRP reinforced metal structure.By fracture mechanics analysis model, put forward the bonding strength calculation formula and the effective length of theoretical formulas. By analysis of the interface stress of CFRP reinforced metal beam by deflections, deduce interface stripping stress and shear stress calculation formula of reinforcing plate CFRP reinforced metal beam by deflections, providing the theory basis for the experimental research for next step.This paper Use test methods on the performance of CFRP reinforcement of steel structure material. First In three coordinate measuring machine measured the thickness of CFRP after curing,and get the CFRP bonding layer thickness accurately. Use of temperature box get CFRP expansion coefficient and conclude the scope of the expansion coefficient of composites within 0℃-35℃and different temperature strain change; Meanwhile measure CFRP elastic modulus at room temperature and get the constitutive relationship of composite material.Using the orthogonal experiment design to CFRP plate single shear tests to determine the unidirectional shearing test bond length and compared with theoretical formula; Study with CFRP stress distribution characteristics and the effective component adhesive length and the stripping stress destruction on steel bonded; It also analyzes the stress distribution characteristics, bonding shear failure process and destruction features on steel bonded.Testing of CFRP reinforcement of steel structure by deflections respectively, the only stickup a layer of CFRP cloth, paste three-layer CFRP cloth and pasting CFRP plate loading test three members; Watched experiment phenomenon, records of strain and deflection component changes.This paper presents a "three-dimensional entity-truss-shell element" finite element model,and through finite element model of CFRP reinforcement ANSYS finite element method proceed nonlinear analysis of steel structure. By analysising different types of paste respectively the stress of the steel reinforcement CFRP duplicate that performance analysis, their load a deflection curves, limit bearing capacity and deformation, and the numerical results and experimental results were compared.Through the the systematic theory and experiment research of CFRP reinforced steel members gain several conclusions and recommendations, enrich the existing steel structure reinforcement theory, provide the basis for the design and construction in engineering practice for CFRP reinforcement repair steel structure.