scholarly journals Seismic Analysis of Isolated Continuous Bridge considering Influence of Seawater and Site Condition

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Baokui Chen ◽  
Yujie Du ◽  
Yan Shi ◽  
Li Fan
Keyword(s):  
Seismic Response ◽  
Seismic Wave ◽  
Seismic Analysis ◽  
Bending Moment ◽  
Coupling Model ◽  
Relative Displacement ◽  
Internal Force ◽  
Site Condition ◽  
Continuous Girder Bridge ◽  
Isolated Bridge

The effects of seawater and site conditions on the seismic response of the isolated continuous girder bridge are evaluated in this study. The seawater-muddy soil-isolated bridge coupling model is built in the dynamic analysis software ADINA, and the external seismic wave input is realized by the seismic wave motion analysis program. The influences of seawater and muddy soil on the seismic response of isolated continuous girder bridges are determined by comparing different offshore site models. The results indicated that the seawater and the muddy soil magnify the displacement of the seabed. The existence of seawater increases the longitudinal relative displacement of piers by 20%–40% but has limited influence on the bending moment and shear force of piers. The muddy soil can increase the longitudinal relative displacement and internal force of the piers remarkably. Moreover, the displacement of bridge bearings increases significantly under the combined influence of muddy soil and seawater. In the seawater-muddy soil-isolated bridge coupling model, the seawater and site condition can influence the seismic performance of sea-crossing bridges obviously.

scholarly journals Near-Fault Seismic Response Analysis of Bridges Considering Girder Impact and Pier Size

Mathematics ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 704
Author(s):  
Wenjun An ◽  
Guquan Song ◽  
Shutong Chen
Keyword(s):  
Seismic Response ◽  
Bending Moment ◽  
Expansion Method ◽  
Response Analysis ◽  
Seismic Action ◽  
Transient Wave ◽  
Cross Sectional ◽  
Displacement Response ◽  
Near Fault ◽  
Continuous Girder Bridge

Given the influence of near-fault vertical seismic action, we established a girder-spring-damping-rod model of a double-span continuous girder bridge and used the transient wave function expansion method and indirect modal function method to calculate the seismic response of the bridge. We deduced the theoretical solution for the vertical and longitudinal contact force and displacement response of the bridge structure under the action of the near-fault vertical seismic excitation, and we analyzed the influence of the vertical separation of the bridge on the bending failure of the pier. Our results show that under the action of a near-fault vertical earthquake, pier-girder separation will significantly alter the bridge’s longitudinal displacement response, and that neglecting this separation may lead to the underestimation of the pier’s bending damage. Calculations of the bending moment at the bottom of the pier under different pier heights and cross-sectional diameters showed that the separation of the pier and the girder increases the bending moment at the pier’s base. Therefore, the reasonable design of the pier size and tensile support bearing in near-fault areas may help to reduce longitudinal damage to bridges.

scholarly journals Seismic Analysis of Hybrid System Bridge of Multi-Span Continuous Girder and Arches

2020 ◽  
Vol 165 ◽  
pp. 04032
Author(s):  
Kuihua Mei ◽  
Wangwang Fu ◽  
Jufeng Su
Keyword(s):  
Finite Element ◽  
Seismic Response ◽  
Wave Velocity ◽  
Traveling Wave ◽  
Seismic Isolation ◽  
Bending Moment ◽  
Internal Force ◽  
Wave Effect ◽  
Traveling Wave Effect ◽  
Large Mass Method

The Chengdong Hanjiang Bridge in Ankang City is a multi-span continuous beam-arch combination system bridge of (75+2×125+160+2×125+75) m, and its site is located in the earthquake zone. Calculation model based on Midas / Civil finite element software process analysis method is applied to seismic response analysis using power. At the same time, in order to influence the travelling wave effect and the seismic isolation system on the internal force of the bridge structure, corresponding finite element models were established and calculated with time history analysis. The finite element model under non-uniform excitation uses the “Large Mass Method” (LMM) for analysis and calculation under different wave velocity multi-point excitations. The results show that after considering the traveling wave effect, the displacement and bending moment of the control section of each hole increase, and the internal force of the fixed pier increases. When the wave velocity is 600m/s, the traveling wave effect strengthens the seismic response of the structure the most. With the increase of the wave velocity, the seismic response of the structure gradually approaches the seismic response under uniform excitation. After the friction pendulum seismic isolation support is used, it is fixed. The bending moment of Pier No.32 has been reduced by 80%, the stiffness of the whole bridge is more balanced, the forces of each pier are relatively close, and the isolation effect is good.

Analysis on Seismic Behavior of Irregular High-Rise RC Structure Using Eccentrically Braces

2011 ◽  
Vol 243-249 ◽  
pp. 4001-4004
Author(s):  
Shi Qun Guo
Keyword(s):  
Seismic Response ◽  
Torsional Vibration ◽  
Seismic Behavior ◽  
Seismic Analysis ◽  
Relative Displacement ◽  
Vibration Response ◽  
The Self ◽  
High Rise ◽  
High Rise Building ◽  
Rc Structure

An anti-seismic analysis about two structures (an irregular high-rise building and the previous structure using eccentrically braces) is performed to study their torsional vibration response in earthquake. The self-vibration character and relative displacement between different floors are compared. It is found that adding some eccentrically braces properly can reduce the response of torsional vibration and other seismic response of the structures efficiently. From the example mentioned in the paper, it is verified that this method is a simple and economical one.

Analysis on Seismic Pounding of Curved Bridge

2011 ◽  
Vol 90-93 ◽  
pp. 800-804
Author(s):  
Qiang Xu ◽  
Xing Jun Qi
Keyword(s):  
Three Dimensional ◽  
Time History ◽  
Bending Moment ◽  
Relative Displacement ◽  
Internal Force ◽  
Curved Bridge ◽  
Reference Base ◽  
History Analysis ◽  
Seismic Pounding ◽  
The Impact

Based on the impact phenomenon between the end of the beam and the bridge abutment of the curved continuous bridge during earthquakes, a spatial finite element calculating model with collision element is presented. The law of collision is studied by the nonlinear contact time history analysis method under two three-dimensional ground motions. The variation laws of relative displacement and the internal force at the bottoms of piers are researched. In addition the changing of displacement and internal force at the end diaphragm are studied. The results show that the pounding action can easily lead to significant collision forces between the end beam and the abutment of the curved bridge which increases the axial force of girder evidently. The collision forces and longitudinal displacements from the inner to outer of the diaphragm generally are showed by an increasing trend, and the pounding action is more fierce under Elcentro ground motion than that under Tianjin ground motion.There is no relative displacement of consolided pier, bending moment and shear force of the consolided pier are greater than that of the mobile pier.The conclusions from the present study may serve as a reference base for seismic design of continuous curved bridges.

Influence of Soil-Pile Interaction on Seismic Mitigation Effectiveness with FPB for Curved Girder Bridge

2011 ◽  
Vol 368-373 ◽  
pp. 971-974
Author(s):  
Xing Jun Qi ◽  
Shu Gang Chen
Keyword(s):  
Seismic Response ◽  
Three Dimensional ◽  
Internal Force ◽  
Calculation Model ◽  
Continuous Girder Bridge ◽  
Pile Interaction ◽  
Plane Shape ◽  
Girder Bridge ◽  
Friction Pendulum ◽  
Main Girder

The seismic response of curved girder bridge is more complex because of its irregular plane shape. Friction pendulum bearing (FPB) has a positive effect on structural seismic response. The seismic response mitigation effectiveness of FPB to curved girder bridge with soil-pile interaction considered is needed to research. The three-dimensional calculation model of a curved continuous girder bridge is established, and FPB are added at the positions of sliding bearings with soil-pile interaction. The influence of soil-pile interaction on seismic response mitigation effectiveness of FPB is computed and analyzed under three-dimensional ground motion action. The results show that the seismic response mitigation effectiveness of FPB is quite obvious with or without soil-pile interaction considered. Furthermore, seismic response mitigation effectiveness of FPB increases for the internal force of piers after soil-pile interaction considered. FPB has great and positive mitigation effectiveness on the seismic longitudinal displacement of the main girder of curved girder bridge, but with soil-pile interaction considered the mitigation effectiveness decreases a bit.

Seismic Mitigation Analysis of Viscous Dampers for Curved Continuous Girder Bridge

2011 ◽  
Vol 90-93 ◽  
pp. 1230-1233 ◽  
Author(s):  
Yi Liu ◽  
Xing Jun Qi ◽  
Yi Jian Wang ◽  
Shu Gang Chen
Keyword(s):  
Seismic Response ◽  
Coupling Effect ◽  
Three Dimensional ◽  
Internal Force ◽  
Viscous Dampers ◽  
Absorption Effect ◽  
Curved Bridge ◽  
Continuous Girder Bridge ◽  
Girder Bridge ◽  
Seismic Mitigation

The seismic response of curved girder bridge is more complex because of its irregular plane shape, therefore, the systematic study of an effective seismic mitigation method is required. In this article, the three-dimensional computational model of a double-pier curved continuous girder bridge is established and viscous dampers are added at the positions of sliding bearings. The full-bridge seismic response absorption effect is analyzed with the viscous dampers damping method under three ground motions of different frequency spectrum characteristic, and each ground motion contains three-direction. The results show that viscous dampers can reduce the difference of internal force between inner pier and outer pier in double-pier curved bridge, and it can also effectively reduce the bending and twisting coupling effect of curved bridge. But viscous dampers are sensitive to seismic spectrum to some degree, therefore seismic response absorption effect and sensitivity should be considered comprehensively when viscous dampers are selected.

scholarly journals Internal Force on and Deformation of Steel Assembled Supporting Structure of Foundation Pit under Thermal Stress

2021 ◽  
Vol 11 (5) ◽  
pp. 2225
Author(s):  
Fu Wang ◽  
Guijun Shi ◽  
Wenbo Zhai ◽  
Bin Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Bending Moment ◽  
High Strength ◽  
Element Model ◽  
Internal Force ◽  
Foundation Pit ◽  
Dimensional Finite Element ◽  
Influence Of Temperature On ◽  
Scale Experiment ◽  
Three Dimensional Finite Element

The steel assembled support structure of a foundation pit can be assembled easily with high strength and recycling value. Steel’s performance is significantly affected by the surrounding temperature due to its temperature sensitivity. Here, a full-scale experiment was conducted to study the influence of temperature on the internal force and deformation of supporting structures, and a three-dimensional finite element model was established for comparative analysis. The test results showed that under the temperature effect, the deformation of the central retaining pile was composed of rigid rotation and flexural deformation, while the adjacent pile of central retaining pile only experienced flexural deformation. The stress on the retaining pile crown changed little, while more stress accumulated at the bottom. Compared with the crown beam and waist beam 2, the stress on waist beam 1 was significantly affected by the temperature and increased by about 0.70 MPa/°C. Meanwhile, the stress of the rigid panel was greatly affected by the temperature, increasing 78% and 82% when the temperature increased by 15 °C on rigid panel 1 and rigid panel 2, respectively. The comparative simulation results indicated that the bending moment and shear strength of pile 1 were markedly affected by the temperature, but pile 2 and pile 3 were basically stable. Lastly, as the temperature varied, waist beam 2 had the largest change in the deflection, followed by waist beam 1; the crown beam experienced the smallest change in the deflection.

scholarly journals Transient Response of Bridge Piers to Structure Separation under Near-Fault Vertical Earthquake

2021 ◽  
Vol 11 (9) ◽  
pp. 4068
Author(s):  
Wenjun An ◽  
Guquan Song
Keyword(s):  
Large Scale ◽  
Bending Moment ◽  
Relative Displacement ◽  
Superposition Method ◽  
Longitudinal Displacement ◽  
Transient Wave ◽  
Vibration Period ◽  
Vertical Excitation ◽  
Mode Superposition Method ◽  
Main Girder

Given the possible separation problem caused by the double-span continuous beam bridge under the action of the vertical earthquake, considering the wave effect, the transient wave characteristic function method and the indirect mode superposition method are used to solve the response theory of the bridge structure during the earthquake. Through the example analysis, the pier bending moment changes under different vertical excitation periods and excitation amplitudes are calculated. Calculations prove that: (1) When the seismic excitation period is close to the vertical natural vibration period of the bridge, the main girder and the bridge pier may be separated; (2) When the pier has a high height, the separation has a more significant impact on the longitudinal displacement of the bridge, but the maximum relative displacement caused by the separation is random; (3) Large-scale vertical excitation will increase the number of partitions of the structure, and at the same time increase the vertical collision force between the main girder and the pier, but the effect on the longitudinal displacement of the form is uncertain; (4) When V/H exceeds a specific value, the pier will not only be damaged by bending, but will also be damaged by axial compression.

Effect of Structure-Soil-Structure Interaction (SSSI) between Three Dissimilar Adjacent Bridges

2021 ◽  
Author(s):  
Mohanad Talal Alfach ◽  
Ashraf Ayoub
Keyword(s):  
Seismic Response ◽  
Seismic Behavior ◽  
Soil Structure ◽  
Soil Structure Interaction ◽  
Numerical Analyses ◽  
Seismic Responses ◽  
Structure Interaction ◽  
Internal Forces ◽  
Isolated Bridge ◽  
Effect Of Structure

Abstract The present study assesses the effect of Structure-Soil-Structure-Interaction (SSSI) on the seismic behavior of three dissimilar adjacent bridges by comparing their seismic responses with the seismic response of the isolated bridge including Soil-Structure-Interaction (SSI). To this end, an extensive series of numerical analyses have been carried out to elicit the effects of Structure-Soil-Structure-Interaction (SSSI) on the seismic behavior of three dissimilar bridges with different superstructure masses. The studied bridges are based on groups of piles founded in nonlinear clay. A parametric study has been performed for configurations of three dissimilar bridges with superstructure masses ratios of 200% and 300%, concentrating on the influence of the inter-bridge spacing, and the geometrical position of the bridges towards each other and towards the seismic excitation direction. The numerical analyses have been conducted using a three-dimensional finite difference modeling software FLAC 3D (Fast Lagrangian analysis of continua in 3 dimensions). The results of the numerical simulations clearly show that the seismic responses of the dissimilar grouped bridges were strongly influenced by the neighboring bridges. In particular, the results reveal a salient positive impact on the acceleration of the superstructure by a considerable drop (up to 90.63%) and by (up to 91.27%) for the internal forces induced in the piles. Comparably, the influence of bridge arrangement towards the seismic loading were prominent on both of superstructure acceleration and the internal forces in the piles. The responses were as much as 27 times lesser for the acceleration and 11 times smaller for the internal forces than the response of the isolated bridge. Contrarily, the inter-bridge spacing has a limited effect on the seismic response of the grouped bridges.

Comparative Evaluation of Mode Combination Methods in Seismic Analysis Using Response Spectrum Method for Tank Structure Using FEA - Seismic FEA

2011 ◽  
Vol 110-116 ◽  
pp. 5240-5248
Author(s):  
Sujay Shelke ◽  
H.V. Vankudre ◽  
Vinay Patil
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Initial Step ◽  
Relative Displacement ◽  
Geometrical Parameters ◽  
Response Spectrum Method ◽  
Spectrum Method ◽  
Combination Methods ◽  
Eigen Values ◽  
Modes Of Vibration

Typical seismic analysis using response spectrum method involves several steps from the initial step of extracting the modes. At the initial stage Eigen values are extracted corresponding to the modes of vibration. These give us Eigen vectors which are a series of relative displacement shapes; however these do not correspond to real displacements or stresses. Participation factors asses these Eigen vectors and grades them according to contribution they will have to the overall solution. Based on the spectral seismic acceleration, participation factor is used to calculate the mode coefficient, which is more of a scaling factor to give physical meaning to the values. Once the modes are extracted, the key issue is of combining these modes to obtain the seismic response. The modes cannot be added algebraically in reality as all the modes do not occur at the same time. Hence we employ methods which can add the modes in a more realistic manner. The objective of this paper is to do a comparative study of various mode combination methods with a focus on tank structures and study the effect of various geometrical parameters on the combination methods

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