Study And Design Of Steel-Concrete Hybrid Structure In High-Rise Buildings

Fully taking the advantages of both steel and concrete, steel-concretehybrid structure has been proved to be an economic and efficientstructural system. This paper begins with reviewing the history of hybridstructure and current composite structures design codes of China andother countries. Its mechanics analysis method and design principle areintroduced. Its advantages, disadvantages and some of the unansweredquestions are pointed out. The background project and researchedcontents are also presented in this chapter.Chapter 2 introduces QR method based on news spline basicfunction, variational principle and elasto-plastic stress theory. Then theelasto-plastic computing equations of steel frames-concrete shear wallsbasing on the QR method are derived, and a corresponding program isdesigned using MATLAB. Some project examples are analyzed with thisprogram and results are compared with that of ANSYS, the chapterconcludes the QR method has gathered all the merits of strongadaptability, few unknown parametric variations, high precision andsimple computation.Chapter 3 deals with Pushover-QR (PO-QR) method for staticelasto-plastic analysis of high-rise buildings, which combines the QRmethod and the Pushover analysis method. The PO-QR method still hiresthe methodology of regular Pushover method in static elasto-plasticanalysis of seismic structures. By replacing the part of finite elementanalysis with the QR method in the process of Pushover analysis andmaking full use of the advantages of both methods, PO-QR methodgreatly simplifies the calculation of static elasto-plastic analysis ofseismic structures. Examples adopting the procedure of the PO-QRmethod show that it is an economic, efficient and feasible analysis method.In the fourth chapter, the system capacity design approach andperformance-based seismic design criteria of members are put forward,which combines the feature of steel-concrete hybrid structure with theenergy theory, failure mechanism control concept. By controlling theseismic resistance capacity difference between substructures, thedisplacement mode and failure mechanism of the whole structure can bedetermined by the main substructure. Therefore, the inelastic seismicresponse and energy dissipation distribution pattern, which is the keyproblem in performance/displacement based seismic design, can bedetermined. Using an actual project as example, the ductility designapproach is finally presented, which can meet the seismic resistancecapacity demand of steel-concrete hybrid structure in high-rise residentialbuildings.Chapter 5 focuses on the numerical analysis method of thetemperature field of concrete-filled steel tubular (CFST) components infire, based on the performance andσ-ε-T constitutive relationsstudies of steel as well as core concrete at high temperature. Throughstudying the mechanics behavior of fame in steel-concrete hybridstructure under ISO-834 standard fire, and simulating the differentbehavior between single CFST column and integral CFST frames ofsteel-concrete hybrid structure under fire using nonlinear finite elementmethod, it has been concluded that the fire resistance requirement for theintegral frames in current code, which is based on the fire test of thesingle column under, is conservative. Changing of load caused by thechange of stiffness of CSFT column in the frame under fire is a veryimportant factor, and the redistribution of loads and interaction betweendifferent members during fire should be considered. The rigid connectionof steel frame can improve the fire performance of the integral structure,while hinged connection between frames and shear wall is good enough.Chapter 6 is dedicated to the analysis of differential shorteningbetween steel columns and reinforced concrete walls/cores, based on ahigh-rise residential building of steel-concrete hybrid structural systemsubjected to gravity loads. Taking the concrete creep and shrinkage intoaccount, the simplified method and the software SAP2000, of which thevertical loads are applied to the structure floor by floor to simulate theconstruction process, are used to calculate the differential shortening.Results showed that the differential shortening is more than 55mm for a 100-meter-high residential building with steel-concrete hybrid structuralsystem because of its architectural function characteristics. With the useof CFST columns, reasonable arrangement of framing system, properconnections between beams and columns/walls, and appropriateconstruction procedures, the differential shortening between columns andwalls/cores can be decreased significantly.