Nonlinear Analysis And Experimental Research On Performance Of High-Pier With Concrete Filled Steel Tube Laminated Laced Columns

With the vigorous development of highway constructions in our country, the bridge construction has climaxed unprecedentedly When the highway spans deep groove valley the high-piers are needed frequently in the mountainous and hilly areas. That the span of bridge has became larger and larger and the pier has became higher and higher causes the drop of overall and local stiffness. Excessively high bridge piers will cause the strong nonlinear effects and adverse effects to bridge seismic. The under construction Yalu highway passes through the gorges region with extremely complex geomorphology and geology in the high intensity area for earthquake. After comprehensive consideration of various factors a new kind of high-pier with laminated laced columns has been proposed by engineers. This kind of structural style combines the structure characteristics of concrete filled steel tube(CFST) and steel reinforced concrete. Because it is adoped for the first time in China,there are no design criteria and project experience for reference by now.In this thesis, the structural behavior of high-pier with CFST laminated laced columns under the serviceability limit state and geometry nonlinear effects under maximum cantilever-construction stage are systematically studied, and the following creativity work and achievements are included:1) In this thesis, domestic applications of CFST laced columns to the single-story workshop, the equipment fames and bridges are summarized; The reseach achievements and present status of CFST laced columns and CFST laminated columns are introduced.2) The model load test under the serviceability limit state has been given for the No.3 main pier of the Heihegou super large bridge on Yalu load. The structural behavior of high-pier with CFST laminated laced columns, Confinement effect, condition of load transfer between column shafts and web plates and working condition of the diapharagm are studied.3) The numerical calculation model of the No.3 main pier of Heihegou super large bridge is established based on finite element program ANSYS. The comparative analysis of test values and theoretical values is maded and the test values are verified and to be perfect. Further and in-depth Studies of the structural behavior of high-pier with CFST laminated laced columns are done and the foundation of design and calculation for similar bridges is laid.4) The geometric nonlinear theory and approaches to establish and solve nonlinear balance equation are introduced. The influencing factor and processing method of large-displacement effects and P-Δeffects to continuous rigid frame bridge with large-span and high-pier are summarized.5) Taking the No.3 main pier of Heihegou super large bridge and the No.10 main pier of Labajin super large bridge as the example, the effects of different height of piers, geometric properties and lateralties to geometrically nonlinearity under maximum cantilever-construction stage are discussed by using of finite element program ANSYS. Provide references for the engineering Practice.