| Thermal power generation is currently the main power generation method in China.Industrialization,large-scale,high efficiency,and ultra-clean emissions of coal-fired units are the direction strongly supported by national industrial policies,more large-scale ultra-supercritical units will be put into operation in the future.The power station boiler is one of the three main eqiupments of the thermal power plant,the characteristic of the boiler frame is that the boiler body all suspended at the uppermost part of the frame,complex structural system,large number of structural members,full bolt connection,large plate girders and other large components.Large thermal power boilers have poor operating environment and serious corrosion,anti-corrosion of components is an important issue in structural design.At present,the boiler frames of large ultra-supercritical units are all made of steel,but there is a problem of large steel consumption,especially the support columns and anti-sideway force members.A single frame column needs to bear a load of 1.0E+5k N,the square cross-sectional side length is more than 2m,and the plate thickness is more than 70mm;the steel brace length is more than 30 m,and the cross-sectional width is up to 900 mm.If the boiler frame adopts concrete-filled steel tube columns and buckling-restrained braces(BRB),it can full use the characteristics of good compressive performance of concrete-filled steel tube and good anti-buckling seismic performance,which can significantly reduce the amount of steel used for structure,and the seismic performance is more superior.In this paper,propose a new type of composite structural system using concrete-filled steel tube columns and buckling-restrained braces applied to the support structure of large boilers,and propose a concrete infilled glass-fibre reinforced polymer(GFRP)tubes used to produce buckling-restrained braces of GFRP tubes,GFRP can improve the corrosion resistance of buckling-restrained brace and realize maintenance-free.Large boilers are often used in high seismic intensity areas,the higher earthquake resistance of the structure is required.Because composite structures possess good seismic performance,also is more economic than steel structures.Therefore,the new composite structure boiler framework system has broad application prospects.In this paper,the performance of GFRP tube anti-buckling,a new type of composite component,is systematically tested and analyzed by finite element simulation.On this basis,the seismic performance test and finite element of the composite structure of the steel tube concrete column-GFRP tube buckling-restrained brace plane composite frame are completed,the verified finite element model was used to simulate and analyze the seismic performance of the boiler tube structure with concrete-filled steel tube columns and buckling-restrained braces.The main results are as follows:(1)Complete 11 BRB test specimens with GFRP tube filled concrete,study the influence of casing tube type,slenderness ratio,constraint ratio and other parameters on the performance of buckling-restrained brace under reciprocating load,and analyze under different parameters such as failure mode,bearing capacity,stiffness,energy dissipation capacity of buckling-restrained brace.The research results show that the GFRP tube buckling-restrained brace has greater rigidity and higher bearing capacity,shows superior energy dissipation capacity under reciprocating loads,and has good seismic performance.In buckling-restrained brace members,GFRP tubes can be used instead of traditional steel tube.(2)The ABAQUS finite element software was used to establish the finite element analysis model of the GFRP tube buckling-restrained brace member,the interaction between the GFRP tube constrained member and the steel core component is considered;the mechanical performance of typical GFRP tube buckling-restrained brace members was analyzed;the design method of GFRP tube buckling-restrained brace is proposed,and the related structural requirements and design suggestions of new buckling-restrained brace members are proposed,the research results can provide reference for the engineering application of such components.(3)Proceed the test of the square concrete filled steel tube frame-GFRP tube buckling-restrained brace system,and the comparative test of the square concrete filled steel tube frame;study the deformation development process and failure mode of the two types of structural systems under the reciprocating load;analyze the performance indexes such as the stiffness,bearing capacity and energy dissipation capacity of the structural system,and analyze the contribution of the GFRP tube buckling-restrained brace to the structural rigidity and bearing capacity through the key test data;the test results show that: both types of structural systems have superior seismic performance,GFRP tube buckling-restrained brace can significantly improve the stiffness,bearing capacity and energy dissipation capacity of the structural system.(4)Use test results to verify the rationality of parameters such as element type and material constitutive parameters.On this basis,finite element model of the large boiler frame structure system was established,the seismic performance of large boiler structural system using square concrete filled steel tube frame-GFRP buckling-restrained brace and large boiler structural system using square concrete filled steel tube frame-steel brace structure is analyzed;structural response of the two structural systems ware obtained,and compared the seismic performance of the two structural systems;through the IDA analysis,the reasonable values of the structural response correction coefficient and displacement amplification coefficient of the two structural systems ware obtained;base shear and the top displacement of the structure in rare earthquake have obvious decrease;after the buckling-restrained brace is set,the structure response correction factor and displacement amplification factor also increase accordingly. |
PDF Full Text Request