| Some multi-tower cable-stayed bridges are a new type of bridge structure between continuous beam bridges and conventional multi-tower cable-stayed bridges.The main features of this type of bridge are: the main beam has high rigidity,the height of the pylon is short,and the cable stays are concentrated;it has good structural characteristics and economic benefits.Therefore,it is a bridge with great competitive advantages and has broad prospects.Based on the actual engineering background,this paper studies the static behavior and seismic performance of the multi-tower cable-stayed bridge.The main research contents and conclusions are as follows:1.Taking a part of cable-stayed bridge as engineering background,the space model was established by using the finite element software Midas civil,and the reasonable bridging state was studied.2.Five different structural systems were established by changing the supporting conditions of the beam pier tower.Model 1: consolidation of all tower beam tower piers;model 2: consolidation of middle tower and secondary side tower beam piers,side tower pier tower solid The beam is hinged and supported;the model 3: the middle tower beam pier is consolidated,the secondary tower and the side tower pier are consolidated and the beam hinge is supported;the model 4: the middle tower,the secondary tower tower pier and tower tower consolidation,the side tower beam The tower is consolidated and the pier is separated.Model 5: The consolidation of the tower tower and the tower,the secondary tower and the tower tower are consolidated and the pier is separated.The mechanical behavior of the five structural systems is analyzed.:1)Under the road-I class lane load,the secondary side span mid-span deflection,mid-span mid-span deflection,horizontal tower top horizontal displacement,secondary tower top horizontal displacement,middle tower of all tower beam towers The horizontal displacement of the top of the tower is the smallest compared with the other four models;however,under the temperature load,the secondary deflection of the system and the horizontal displacement of the top of the tower are the largest.2)Under the temperature load,the horizontal displacement of the bridge end of all tower beam towers is smaller than the other four models,while the vertical horizontal displacement of the tower top is larger than the other four models;the middle tower and the secondary tower The beam pier is consolidated,the side tower beam tower isconsolidated,and the secondary side span mid-span deflection and the mid-span mid-span deflection are the smallest.The middle tower beam pier is consolidated,and the secondary tower and side tower beam tower are consolidated.The corresponding value of the pier tower separation system is second.3)The deflection of each span and the horizontal displacement of each tower under the action of the live load are smaller than the corresponding values ??of the models4 and 5,and the mid-span mid-span bending moment under the temperature load is smaller than the corresponding of the model 1.Therefore,in terms of reducing the live load displacement and reducing the temperature internal force,in the actual project,the middle tower and the secondary tower tower pier tower are consolidated,the side tower pier tower is consolidated,the beam hinge support and the middle tower beam pier It is more advantageous to consolidate the tower,consolidate the secondary tower and the side tower,and support the two structural systems.3.Analysis and comparison of model 1: all tower beam tower pier consolidation system and model 2: middle tower,secondary side tower beam pier tower consolidation,side tower pier tower consolidation and beam hinge support system its first ten steps of self-vibration The main conclusions of the frequency and mode are as follows:1)The frequency corresponding to the first-order main beam symmetrical vertical bending of model 1 is 0.684191 HZ,the frequency corresponding to the first-order main beam anti-symmetric vertical bending is 0.578459HZ;the frequency corresponding to the first-order main beam symmetrical vertical bending of model 2 is 0.538518 HZ The frequency of the first-order main beam against the vertical bending is 0.435170HZ;the frequency corresponding to the first-order main beam of the model 1 is 18.3% larger than that of the model 2.The first-order main beam of the model 1 opposes the frequency corresponding to the vertical bending.10.3% larger than Model 2.2)The first 10 modes of the two systems have no torsion,and the main beam is mainly vertical.The seismic response of five supporting systems was analyzed based on response spectrum method and time history analysis.The conclusions reached are as follows:1)The displacement values ? ? of the tower-top bridges obtained by the two analysis methods are far greater than the vertical displacement.Therefore,in the seismic design,the seismic design of the tower should be considered.Under the action of earthquakes,the two sides of the five structural systems are The internal force of the side tower is always at a relatively high level,so it should be given enough attention inpractical engineering.2)Model 3(consolidation of tower tower and pier,consolidation of secondary tower and side tower and beam hinge support)than model 2(consolidation of middle tower,secondary tower tower and pier tower,consolidation of side tower pier tower)The beam hinge support has a smaller seismic response. |
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