Study On The Shock Absorption Method Of Elastic-Plastic Connecting Beams Between Double Walls Of Piers For Continuous Rigid Frame Bridge

Large numbers of continuous frigid frame bridges were constructed in the southwest and northwest area of China. The piers are higher and higher. At present, the experience of earthquakes in high-pier bridges is lack, and it would be difficult that the high-pier bridges were repaired after earthquakes were occurred. Reasonable design method can weaken the seismic response or avoid the disaster.Guidelines for Seismic Design of Highway Bridges are performed in October2008. It illustrates ductility design in China’s bridge seismic application formally. On the base of energy dissipation of ductility element and improving the aseismatic capability of the high-pier bridge, the main content of this thesis includes:(1) The seismic response is analyzed for double thin-wall high piers of continuous frigid frame bridge, and the character of seismic response in this kind of bridge. Based of the phenomena of energy dissipation of elastic-plastic beam, using the seismatic method of the new San Francisco-Oakland Bay East Bridge for reference, this thesis bring forward a new damping concept design method:setting elastic-plastic beam between double thin-wall piers.(2) The basic structural parameters are sum up for double thin-wall piers of continuous frigid frame bridge, and make sure these parameters’range for this dissertation, and study out the basic parameters of elastic-plastic beams.(3) Changing the rigidity, length, position and density-placed, more groups of calculation models are set up with Sap2000software. The shock absorption effect of elastic-plastic beams is analyzed when changing the parameters. The results reveal: the length and density-placed is insensitive for shock absorption effect; the appropriate rigidity is more effective; the elastic-plastic beams of the1/3part along the piers bottom are disadvantageous.(4) The shock absorption effect of elastic-plastic beam is analyzed and compared when changing the span, the height of the piers, the height-span ratio and the thickness-span ratio of the continuous frigid frame bridges. The results reveal:the span is longer, the shock absorption effect is more for moment of the bottom of piers; in the bridge with low piers the shock absorption effect is not too obvious.(5)The shock absorption effect of elastic-plastic beam is analyzed when considering different earthquake waves on different ground and different acceleration peak of earthquake wave. The results reveal:the ground is softer, and acceleration peak of earthquake wave is higher, then the seismic response is stronger, and the shock absorption effect of the elastic-plastic beam is more obvious.(6) The static reactions, seismic response and stability effects are analyzing by the means of five constructed bridge examples when setting elastic-plastic beam between double walls of piers. When analyzing the first example’s calculation, temperature change, live load, shrinkage and creep of concrete are taken into account. It reveals the new method is feasible.(7) Summing up the study on setting elastic-plastic beam between double thin-wall piers of continuous frigid frame bridges, the applicative implementation procedures are brought up for the bridge designer and the scientific research personnel. The relational table of the height of pier and the sectional stiffness of elastic-plastic beam is submitted for the Category II ground.