Damper Optimization for Long-Span Suspension Bridges

2013 ◽  
pp. 112-125
Author(s):  
Hao Wang ◽  
Aiqun Li ◽  
Zhouhong Zong ◽  
Teng Tong ◽  
Rui Zhou
Keyword(s):  
Seismic Response ◽  
Optimization Method ◽  
Sensitivity Analyses ◽  
Suspension Bridges ◽  
Seismic Responses ◽  
Control Effect ◽  
Analytic Hierarchy ◽  
First Order ◽  
Traveling Wave Effect ◽  
Long Span

Long-span suspension bridges are becoming prevalent globally with the rapid progress in design methodologies and construction technologies. Although with apparent progress, the balance between excessive displacement and inner forces, under dynamic loads, is still a main concern because of increased flexibility and low structural damping. Therefore, effective controllers should be employed to control the seismic responses to ensure their normal operation. In this chapter, the combination of the analytic hierarchy process (AHP) and first-order optimization method are formulated to optimize seismic response control effect of the Runyang suspension bridge (RSB) under earthquakes, considering traveling wave effect. The compositive optimal parameters of dampers are achieved on the basis of 3-dimensional nonlinear seismic response analyses for the RSB and parameters sensitivity analyses. Results show that the dampers with rational parameters can reduce the seismic responses of the bridge significantly, and the application of the AHP and first-order optimization method can lead to accurate optimization effects.

Compositive Optimal Control for the Seismic Response of a Long-Span Triple-Tower Suspension Bridge

2018 ◽  
Vol 18 (08) ◽  
pp. 1840009 ◽  
Author(s):  
Hao Wang ◽  
Yifeng Wu ◽  
Ben Sha ◽  
Wenzhi Zheng ◽  
Yuqi Gao
Keyword(s):  
Optimal Control ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Seismic Responses ◽  
Viscous Dampers ◽  
Analytic Hierarchy ◽  
Expansion Joints ◽  
Elastic Links ◽  
Long Span ◽  
Floating System

In the design of super-long-span suspension bridges, the floating system is commonly adopted. However, this system may lead to the excessive earthquake-excited longitudinal displacement (LD) at the end of the main girder, which in return could result in pounding damage at expansion joints. In this paper, Taizhou Bridge, the triple-tower suspension bridge with the longest main span in the world, is taken as an example to demonstrate the effectiveness of three different approaches (elastic links, viscous dampers, and their combination) of mitigating the possible excessive LD. The finite element code ABAQUS is used to build the numerical model of the bridge and calculate the dynamic characteristics as well as the seismic responses. Then, 24 cases with different parameters of elastic links and viscous dampers are investigated and it is observed that the mitigation effect of the 24 cases varies significantly with different parameters. To obtain the optimized mitigation effect for seismic responses, including the LD of the girder, the LD and shear force of all towers, in the 24 cases, the modified analytic hierarchy process (AHP) method is introduced to realize the compositive optimal control of the triple-tower suspension bridge. Results show that the 24th case is the optimal one in which the LD of the girder is reduced significantly while the inner force of towers does not get excessive increase.

Seismic Response Analysis of the Numerical Simulation Method on Cable-Stayed Bridge Tower which Considers the Rigid Foundation

2014 ◽  
Vol 875-877 ◽  
pp. 998-1002
Author(s):  
Wei Bing Luo ◽  
Ji Ming Fan ◽  
Ji Lv ◽  
Li Ya Zhang ◽  
Cui Cui Wu
Keyword(s):  
Seismic Response ◽  
Ground Motions ◽  
Simulation Method ◽  
Response Analysis ◽  
Rigid Foundation ◽  
Seismic Responses ◽  
Near Fault ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Bridge Tower

The seismic responses under the action of far-fault and near-fault ground motions of the bridge tower structure of the long-span cable-stayed bridge are numerically discussed by means of the model of the bottom consolidation of the column. The results show that the responses of tower of the cable-stayed bridge correlate well with the properties of the ground motions. The seismic responses of the model have much larger values under the near-fault velocity pulse-like ground motions than those of the counterpart. The frequency of system reduces as the flexibility of structure decreases because of the rigid foundation; The displace response of tower shows that the rigid foundation has little influence on the seismic response of the cable-stayed bridge, while the acceleration response of the tower implies that rigid foundation has adverse effect. Thus, consideration of the soil-pile-superstructure interaction can be meaningful both in theory and reality during the seismic design of long-span cable-stayed bridge structure.

Aerodynamic Countermeasure Schemes of Super Long-Span Suspension Bridges with Various Aspect Ratios

2020 ◽  
Vol 20 (05) ◽  
pp. 2050061 ◽  
Author(s):  
Yongxin Yang ◽  
Yaojun Ge ◽  
Rui Zhou ◽  
Shiguo Chen ◽  
Lihai Zhang
Keyword(s):  
Aspect Ratio ◽  
Suspension Bridges ◽  
Shape Variation ◽  
Control Effect ◽  
Long Span Bridges ◽  
Long Span ◽  
Aspect Ratios ◽  
Typical Aspect ◽  
Wind Barrier ◽  
Girder Bridge

The purpose of this study is to investigate the flutter control scheme of super long-span bridges with various aspect ratios (e.g. width to height (B/H)) using passive aerodynamic countermeasures. Through a series of wind tunnel testing and theoretical analysis, three types of passive aerodynamic countermeasures, i.e. vertical central stabilizer (VCS), wind barrier and inspection rail, were investigated for five typical aspect ratios of a closed-box girder bridge. The results show that both the aspect ratio and flutter critical wind speed generally increase with the decrease of the ratio of torsional and vertical frequencies of the bridge. In the case of an aspect ratio of 8.9, a downward VCS (DVCS) has a much better flutter performance than that of an upward VCS (UVCS) because aerodynamic damping of Part A and Part D could produce a higher heaving degree of freedom (DOF) participation level. Furthermore, the position variation of wind barriers is superior to their shape variation for the bridge with an aspect ratio of 8.3, and the flutter performance of the girder with a combination of the wind barrier (WB3P3) and UDVCS with 0.3[Formula: see text]h/H DVCS appears to be better than that without countermeasures. In addition, the installation of an inspection rail near the bottom point of an inclined-web (IR3) has the best flutter control effect among four positions of inspection rails.

Seismic Response of Long Span Continuous Rigid-Framed Steel Arch Bridge

2018 ◽  
Vol 763 ◽  
pp. 1087-1094
Author(s):  
Ai Rong Liu ◽  
Yong Lin Pi
Keyword(s):  
Seismic Response ◽  
Shear Wave ◽  
Traveling Wave ◽  
Wave Speed ◽  
Wave Effect ◽  
Earthquake Excitation ◽  
Arch Bridge ◽  
Shear Wave Speed ◽  
Traveling Wave Effect ◽  
Long Span

This paper investigates seismic responses of Xinguang Bridge, a 3-span continuous rigid-frame and steel-truss arch bridge. Earthquake excitation input is a key issue for the seismic analysis. This paper uses a finite element method to study the traveling wave effect on Xinguang Bridge and its interaction with the dynamic properties of the bridge under the condition of two steps and two levels probability. The seismic response of the bridge under the coincident earthquake excitation is also analyzed. Comparisons show that the seismic response of the long-span bridge by considering the traveling wave effect is much different from that under consistent earthquake excitation. The influence of the shear wave speed on the seismic response of the long span continuous bridge is also explored and the shear wave speed is found to greatly affect the wave shape and magnitude of the time-history of the longitudinal displacement at the crown of the main arch of the bridge. It is concluded that traveling wave effect and shear wave speed of ground have significant influences on the seismic response of the long span continuous rigid-framed and steel-truss arch bridge.

Analysis of Traveling Wave Effect on Half-Through CFST Arch Bridge by Large Mass Method

2013 ◽  
Vol 540 ◽  
pp. 21-28 ◽  
Author(s):  
Jun Ma ◽  
Yan Li
Keyword(s):  
Seismic Response ◽  
Traveling Wave ◽  
Large Mass ◽  
Wave Effect ◽  
Arch Bridge ◽  
Traveling Wave Effect ◽  
Long Span ◽  
Cfst Arch Bridge ◽  
Internal Forces ◽  
Large Mass Method

For long span arch bridges, the traveling wave effect is an important aspect on seismic response of structure which cannot ignore. The Big Mass Method was used to analyze the seismic response of a half-through CFST arch bridge under both uniform and non-uniform excitations. The results showed that the traveling wave effect caused by non-uniform excitation led to more obvious seismic response in both internal forces and displacements. The skewback section was most dangerous. The waveform of internal forces caused by non-uniform excitation was quite similar to that caused by uniform excitation, but the amplitude of the latter is bigger than the former. It can conclude that the traveling wave effect would cause the unsynchronized vibration to the structure elements which led to the lager responses.

Effect of Pounding at Expansion Joints on Seismic Response of Long-Span Suspension Bridge under Strong Earthquakes

2010 ◽  
Vol 163-167 ◽  
pp. 4373-4377
Author(s):  
Yu Lin Deng ◽  
Xiong Jun He
Keyword(s):  
Time History ◽  
Suspension Bridge ◽  
Relative Displacement ◽  
Suspension Bridges ◽  
Seismic Responses ◽  
Expansion Joints ◽  
Strong Earthquakes ◽  
Seismic Displacement ◽  
Long Span ◽  
History Analysis

For a long-span suspension bridge, owing to a flexible structure system, the seismic displacement at the end of the deck may severely exceed the allowance under earthquake which due to the occurrence of the pound between the main span and the approach span usually which can causes the collision of falling-beams and structures. In this paper, based on the pounding phenomenon at expansion joints of long-span suspension bridge under strong earthquake and employing a typical long-span suspension bridges. With the time history analysis method of determining the nonlinear seismic responses, the pounding effects of adjacent girders at expansion joints on seismic responses of long-span cable-stayed bridge were studied. The results indicate that pounding can amplify the seismic demand of piers of the approach span and can also amplify the displacement of beam of the approach span, the relative displacement between main span and approach span and the hinge seat width of beam of approach span obviously and it causes easily the collision of falling-beams and structures under earthquakes.

scholarly journals Traveling Wave Resonance and Simplified Analysis Method for Long-Span Symmetrical Cable-Stayed Bridges under Seismic Traveling Wave Excitation

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Zhong-ye Tian ◽  
Meng-lin Lou
Keyword(s):  
Wave Velocity ◽  
Traveling Wave ◽  
Longitudinal Direction ◽  
Wave Excitation ◽  
Seismic Responses ◽  
Excitation Process ◽  
Long Span Bridges ◽  
Traveling Wave Effect ◽  
Long Span ◽  
Wave Resonance

The seismic responses of a long-span cable-stayed bridge under uniform excitation and traveling wave excitation in the longitudinal direction are, respectively, computed. The numerical results show that the bridge’s peak seismic responses vary significantly as the apparent wave velocity decreases. Therefore, the traveling wave effect must be considered in the seismic design of long-span bridges. The bridge’s peak seismic responses do not vary monotonously with the apparent wave velocity due to the traveling wave resonance. A new traveling wave excitation method that can simplify the multisupport excitation process into a two-support excitation process is developed.

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