The Vibration Reducing Performance Of Singale-layer Combined Lattice Shell Considering Sub-structure

Engineers make great efforts on damping of constructions and gain obvious fruits in recent thirty years. The most remarkable thing is "the protective system of structure". Instead of improving resistance capability by enhancing the rigidity of beam, column and wall, it depends on utilizing the characteristic of dynamical capability of structure and damping system to avoid or reduce damages by earthquake. Buckling-Restrained Braces is a kind of excellent energy dissipation structural. BRB consist of three parts, a steel core plate surrounded by mortar and enclosed in a steel tube and a membrane called the un-bonding material between the core plate and the mortar. Nuclear steel brace can reach full yield under tension and pressure, its ductility is well and has stable and full hysteresis loop, and BRBs with low yield can dissipate energy on the small displacement level.Single layer combined lattice shell consists of two hemi-sphere shell and a cylindrical shell, this shell has a strong practicability. By taking into account of sub-structure, the research in this article is much more closer to practice and more propitious on application. But in the dynamical efforts of earthquake, research of the mechanical capability of the single layer combined lattice shell considering sub-structure and damping research is still primary either at home or overseas. The main contents are as follows:First of all, a program is made according to the types of combination shell and members connection law to realize automatic modeling, grids calculation and members' cross-section selection are derived from the regulation of approximate equivalence of stable bearing capability, the shell is analyzed in both static and dynamic, the shell deformation mode and nodal displacement distribution law is known clearly. Secondly, the modes under natural vibration model are compared by analyzing single-layer combined lattice shell and the shell with sub-structure. And the dynamic response is analyzed under El-Centro seismic; the impact regulation by length-gyration radius ratio of sub-structure is given, so the impact to the structure by the sub-structure can not be ignored. Third, the primary study on the method of the vibration reducing of the single-layer combined lattice shell with sub-structure is also done. And those four arrangements of BRBs are proposed. The finite element analysis software ANSYS program is applied to complete the concrete structural analysis and to conclude the calculation results. The results that damping regulation and energy dissipating situation of nodal displacement and member force reducing distribution are obtained, and give appraisal on performance of vibration reducing systems by comparison with each other; it shows that the vibration reducing effect is better with reasonable arrangement of BRBs. With different span and different seismic input, the impacts to single layer combined lattice shell with BRBs are analyzed in the paper. Last but not least, it discussed about the vibration reducing performance of BRBs with sub-structure based on BRB3 and educes the efforts of energy dissipation in sub-structure.BRBs arrangements in the shell and between columns, which mentioned in this paper, can be used in the damping analysis of other types of single-layer combined lattice shell. The results that referred can be applied in engineering practices, and give references to further researches.