| The continuous rigid frame bridge combines the stress characteristics of the T-shaped rigid frame and the continuous beam,which has many advantages,such as quick construction,low cost,and less expansion joints.Therefore,this type of bridge is widely used in road construction in China.However,due to the influence of terrain and other conditions,mountainous areas often need to build bridges with long-spans to cross the river.Therefore,the continuous rigid frame bridge needs to develop toward the high pier and the long span Due to the difference of the distribution of structural stiffness in three directions,the long-span continuous rigid frame bridge has a specific law of seismic response under dynamic loading,and the seismic response characteristics of this type of bridge are research is of great significance.This thesis first describes some common bridge damage,briefly describes its internal factors and reflects on it,then introduces the research status of long-span continuous rigid frame bridge and the analysis method of seismic response.Taking the Liye super large bridge(91m+168m+91m)of Autonomous Prefecture of Western Hunan as the engineering background,the finite element model of the consolidation of the pier bottom and the interaction of pile-soil was established by using the large-scale general finite element software Midas/civil.First,the dynamic characteristics of the full bridge were analyzed.Secondly,after studying the stiffness distribution characteristics of the Liye super large bridge,the seismic response of the Liye super large bridge was calculated and analyzed by the response spectrum method and the time history analysis method.Finally,the influence of structural parameters on the seismic response of the Liye super large bridge is discussed,and the following aspects are completed:(1)Calculate the dynamic characteristics of the Liye super large bridge.Comparing and analyzing the vibration mode characteristics of the bridge and the natural frequency characteristics,the characteristics of structural stiffness distribution in three directions are obtained.(2)According to the site characteristics at the bridge site,the corresponding response spectrum is selected,and the seismic response analysis of the bridge pier and the main beam is carried out.After the internal forces and displacement values of the key sections of the bridge pier and the main beam under earthquake action are obtained,the influence of pile-soil interaction on the seismic response of the Liye super large bridge is discussed.(3)Three seismic waves were selected to perform uniform excitation input to the bridge,and the maximum value of seismic wave calculation results was analyzed.After the variation of internal force and displacement of the key section of the bridge pier and the main beam under seismic waves is obtained,the influence of vertical seismic action on the internal force and displacement of the long-span continuous beam bridge is discussed.(4)Three finite element models of different pier height differences and five different pile diameters were established,and the response spectrum method was used for calculation.The dynamic characteristics of the model with different structural parameters and the law of seismic response are compared and analyzed. |
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