Research On Seismic Performance Of Steel Frame In-fill Assembled Phosphogypsum-concrete Composite Wall Structure

Phosphogypsum is an industrial solid waste of the production of phosphoric acid and phosphate fertilizer.The annual output and accumulated stock of phosphogypsum are huge in our country,which poses a serious threat to the ecological environment and the sustainable development of phosphate chemical enterprises.As the country vigorously advocates and urges the resource utilization of phosphogypsum,the annual utilization rate of phosphogypsum in our country has increased year by year,but it is currently only 40%.Every year,more than half of the phosphogypsum is not properly disposed,its harm has not been substantially alleviated.Based on this,this paper proposed the fabricated phosphogypsum-concrete composite wallboard made from phosphogypsum and concrete,applied in the field of steel structure construction,and its seismic performance was studied.First,based on the research idea that environmental protection and energy saving and the large-volume utilization of raw phosphogypsum,the mix ratio of phosphogypsum-based cementing composite was tested and studied,and then focused on the experimental research and finite element numerical calculation of the seismic performance of the steel frame filled fabricated phosphogypsum-concrete composite wall structure.The main research works and results are as follows:(1)Phosphogypsum-based cementing composite were prepared by using raw phosphogypsum as aggregate to be solidified,hemihydrate phosphogypsum,cement and silica fume as cementitious materials,and quick lime as impurity neutralizer of phosphogypsum.The test results show that the utilization rate of raw phosphogypsum is high in this mixing ratio scheme,slurry performance and hardening performance are both excellent,the scheme has the meaning of energy saving,environmental protection,simple process and cost saving.(2)Experimental study on the seismic performance of a pure steel frame and a steel frame filled with fabricated phosphogypsum-concrete composite wall panels under horizontal low-cycle reciprocating loads were carried out.Based on the tests results,the failure modes and various seismic performance indicators of the two frames were compared and analyzed,the influence of composite wall panel on the seismic performance of steel frame structure was revealed.The results show that the energy dissipation capacity of the two frames is good,and the elastic interlayer displacement angle and elastic-plastic interlayer displacement angle meet the specification requirements.The composite wall plate plays the role of oblique support strut in the steel frame,which greatly improves the stiffness and bearing capacity of the structure and delays the structure into yield.However,to some extent,it will reduce the ductility and energy dissipation capacity of the overall structure.The development of its failure makes the overall stiffness degradation curve of the structure show a three-stage development trend,which is very conducive to structural seismic.In summary,the use of phosphogypsum-concrete composite wallboard in the field of steel structure has high feasibility and utilization value.(3)Based on the tests model,the refined finite element calculation model of the two structures under horizontal low-cycle reciprocating load were established.Considering the influence of structural geometry,material,contact nonlinearity and other factors,the calculation results of the two frames were compared with the tests results to verify the rationality and accuracy of the model.Based on the verified finite element model,the influence of phosphogypsum fillers on the seismic performance of the overall structure was analyzed.The results show that the calculated results of the model are in good agreement with the experimental results,the failure modes and seismic performance index are basically consistent with the tests,which can provide a reasonable and efficient finite element calculation method for the relevant seismic model of phosphogypsum-concrete composite wallboard in steel frame.Phosphogypsum filler can effectively improve the bearing capacity and total energy consumption of the overall structure,delay the overall structure into yield,but it will reduce the structural ductility to a certain extent.