Research On Key Construction Technologies Of Concrete-filled Steel Tubular Frame-corewall Structure With Outrigger Truss

With the development of economy,the improvement of building structure system and the continuous improvement of construction technology,high-rise and super high-rise buildings have developed rapidly in today's world.Building a higher building through a good structural system is the goal pursued by structural engineers.The frame-corewall structure has become the mainstream structure adopted in the international high-rise and super high-rise buildings due to its good force characteristics and flexibility of internal space arrangement,and has a wide range of applications.The concrete-filled steel tubular frame-corewall structure with the outrigger truss is a new type of building structure system developed on the basis of the frame-corewall structure,which is composed of the frame structure around the building,the inner corewall structure and the outrigger truss members connecting them.The corewall is composed of the outrigger truss members,which can effectively improve the lateral stiffness of the building structure,so that the structure can reduce the lateral displacement of the structure when it encounters horizontal effects such as earthquake or wind load.This paper takes a project in Zhuhai City,Guangdong Province as the research background,researches on the key construction technologies of concrete-filled steel tubular frame-corewall structure with outrigger truss.The research results will have a certain reference for similar structural construction.(1)Qualities can be ensured by making a large-diameter and thick-walled steel tubular column by rolling process and controlling the assembly process of the inner ring to the reinforcing partition,the T-shaped stiffener,the connecting cow leg and the connecting plate.Assembles the outrigger truss members and then measures the assembly accuracy to ensure that the error is within the allowable range.The Huge round steel tubular column hoisting is divided into two areas on the plane,and the steel tubular column lags on the 10 th floor of the corewall on the facade,the outrigger truss member is hoisted synchronously from the middle to the two sides,that is,the corewall part is hoisted first,and then hoisted outside frame structure,which can guarantee the accuracy of hoisting.(2)The large-diameter and thick-walled steel tubular column is welded on the spot by circumferential partitioning and segmental back-welding at the same time to reduce the welding stress of the thick plate,the two ends of the outrigger truss web members at the strengthened stories are temporarily fixed by mounting bolts,which can ensure that the component can produce a certain displacement.The upper and lower chords are welded first to ensure that the concrete of the slab can be poured,and the web membersare to be welded until the next strengthened story or the roof is finished,so as to reduce the internal force of the web members caused by the difference in settlement between the corewall and the outer frame structure.The automatic shot blasting method is used to rust the steel tubular column and the outrigger truss structure to meet the requirements of the 25-year anti-corrosion and the first-class fire-resistance.(3)Through the development of trial and match,the high-strength and self-compacting C60 concrete can be produced by P.O42.5 ordinary Portland cement,S95 mineral powder,grade I ground fly ash and polycarboxylate water reducer,which can not only meet the requirements of self-compacting and high strength,but also meet the requirements of ultra-high pumping.The quality of concrete can be guaranteed when the high-dropping and self-compacting method is used to pour the concrete in the steel tubular columns and the artificial high-frequency vibrating rod is vibrated in the joint area.(4)The results of construction simulation analysis of the whole structure by MIDAS GEN software show that the construction procedure of the 10 layers of the corewall leading outer frame column selected in this paper is reasonable and feasible,and the internal force of the outrigger truss members can be effectively reducedby constructing the corewall first.Simulates the construction process which considering the concrete shrinkage and creep,and then calculates the vertical deformations of the corewall and the frame columns,and determines the length of the vertical members to be reserved during construction period according to the deformation values.The closing time of the second outrigger truss is when the outer frame steel tubular column to the roof,before its closing,the whole structure is in the most unfavorable working condition,so the deformation check of the wind load is carried out to ensure the safety of the structural construction.