scholarly journals Dynamic Response Evaluation of Long-Span Reinforced Arch Bridges Subjected to Near- and Far-Field Ground Motions

2018 ◽  
Vol 8 (8) ◽  
pp. 1243 ◽  
Author(s):  
Iman Mohseni ◽  
Hamidreza Lashkariani ◽  
Junsuk Kang ◽  
Thomas Kang
Keyword(s):  
Ground Motion ◽  
Dynamic Performance ◽  
Time History ◽  
Bending Moment ◽  
Element Model ◽  
Structural Performance ◽  
Far Field ◽  
Inelastic Behavior ◽  
Earthquake Loads ◽  
Arch Bridges

This study assessed the structural performance of reinforced concrete (RC) arch bridges under strong ground motion. A detailed three-dimensional finite element model of a 400 m RC arch bridge with composite superstructure and double RC piers was developed and its behavior when subjected to strong earthquakes examined. Two sets of ground motion records were applied to simulate pulse-type near- and far-field motions. The inelastic behavior of the concrete elements was then evaluated via a seismic time history analysis. The concept of Demand to Capacity Ratios (DCR) was utilized to produce an initial estimate of the dynamic performance of the structure, emphasizing the importance of capacity distribution of force and bending moment within the RC arch and the springings and piers of the bridge. The results showed that the earthquake loads, broadly categorized as near- and far-field earthquake loads, changed a number of the bridge’s characteristics and hence its structural performance.

Study on the Structural and Aseismatical Performance of Multi-Storey Ancient Chinese Timber Structure Shangyou Tower of Palace Style

2012 ◽  
Vol 535-537 ◽  
pp. 2012-2016
Author(s):  
Da Feng Gao ◽  
Peng Fei Li ◽  
Lei Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Ground Motion ◽  
Vibration Isolation ◽  
Time History ◽  
Element Model ◽  
Timber Structure ◽  
Wooden Frame ◽  
Spring Element ◽  
The Ancient Chinese

Based on the rich previous experimental data, the multi-storey ancient Chinese timber structure shangyou tower of palace style was studied. ANSYS10.0 software was used to establish the finite element models. One finite element model of large wooden frame was established by applying semi-rigid spring element to simulate the joint of mortise-tenon, tou-kung and the connection on column foot in the real wooden structure. The other finite element model of antique building corresponding to the finite element model above was established. The first 10 inherent frequencies and vibrations of the two models were obtained by the method of Block Lanczos with full transient analysis. The model displacement and acceleration time history curves were obtained by taking the two models subjected to El-Centro ground motion, Taft ground motion and Lanzhou artificial ground motion excitation. By the results analysis of the two models, it can be find that the vibration isolation performance of the ancient Chinese timber structure mainly manifests in the column foot, tenon and mortise connection and the tou-kung layer.

scholarly journals Optimization Method for Solving the Reasonable Arch Axis of Long-Span CFST Arch Bridges

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Xuesong Zhang ◽  
Ningyi Liang ◽  
Xiaohong Lu ◽  
Anbang Gu ◽  
Jidong Shan
Keyword(s):  
Yangtze River ◽  
Spline Interpolation ◽  
Bending Moment ◽  
Optimization Procedure ◽  
Element Model ◽  
Optimization Methods ◽  
Optimization Method ◽  
Steel Tube ◽  
Long Span ◽  
Arch Bridges

With the continuous construction of 500 m concrete-filled steel-tube (CFST) arch bridges such as the Bosideng Yangtze River Bridge and the Hejiang Changjiang Highway Bridge, the deviation between the dead pressure line and the arch axis produced by extant arch axis optimization methods increases. Therefore, an arch axis optimization method for long-span CFST arch bridges with a truss section must be designed. Following the optimization of the truss arch axis, this study develops the minimum section eccentricity method that aims to optimize the arch axis of long-span CFST arch bridges. To minimize the main tube eccentricity of the truss arch, the bending moment of the main tubes is reduced by applying the main tube eccentricity method iteratively in a finite element model. Afterward, a smooth and reasonable arch axis is fitted by applying a cubic spline interpolation function in MATLAB. The entire optimization procedure is performed using the Bosideng Yangtze River Bridge as an example. Compared with that of optimal arch axis line types (e.g., parabola and catenary) and other traditional arch axes, the bending moment of main tubes optimized by the proposed method is substantially lower and more uniformly distributed along the arch axis span. The mechanical properties of the finished bridge, including its strength, stiffness, and stability, are all improved, thereby verifying the feasibility of using the proposed method to optimize the arch axis of CFST arch bridges with a truss section.

Analysis on Earthquake Damage of Daxinglu Ramp Bridge in Wenchuan Earthquake

2011 ◽  
Vol 255-260 ◽  
pp. 1003-1006 ◽  
Author(s):  
Guo Hui Zhao ◽  
Yu Min Zhang
Keyword(s):  
Wenchuan Earthquake ◽  
Ground Motion ◽  
Time History ◽  
Element Model ◽  
Natural Period ◽  
Long Period ◽  
Earthquake Record ◽  
Dynamic Time ◽  
Rubber Bearings ◽  
Long Period Ground Motion

Although located in the very low intensity area, the superstructure of Daxinglu Ramp Bridge sustained huge damage in Wenchuan earthquake. The longitudinal displacement of superstructure at the joint was about 400mm, which outdistanced the average displacement of all the other bridges in this area. In this paper, finite element model of the ramp bridge is made by general FEA software and the damage of the ramp bridge is analyzed by using nonlinear dynamic time history method. The results are obtained as follow: (1) the displacements restriction capacity of bearing system is reduced greatly by setting too many movable pot rubber bearings in the bridge. (2) The earthquake record near the bridge site is a typical long period ground motion. The extended natural period of the damaged bridge absorbed more but not less energy from the long period ground motion, which aggravated the damage.

Analysis of Dynamic Performance of Rigid Pile Composite Foundation

2012 ◽  
Vol 256-259 ◽  
pp. 648-651
Author(s):  
Gui Lin Sheng ◽  
Cai Li Su ◽  
De Hui Liu
Keyword(s):  
Response Pattern ◽  
Similarity Theory ◽  
Dynamic Performance ◽  
Dynamic Test ◽  
Time History ◽  
Element Model ◽  
Composite Foundation ◽  
Group Model ◽  
Rigid Pile ◽  
Rigid Pile Composite Foundation

The paper established 3-D finite element model, studied the response pattern of rigid pile composite foundation under earthquake loading with time history analysis method. According to similarity theory, this paper established rigid pile composite foundation pile group model, analyzed the response pattern of it with pseudo-dynamic test methods. And compared and analyzed the results which were obtained by different methods, based on these analyses, some conclusions which may be of some value for anti-seismic design of this type of composite foundations are drawn

scholarly journals Seismic fragility analysis for tall pier bridges with rocking foundations

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Xu Chen ◽  
Jianzhong Li
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Fragility Curves ◽  
Dynamic Performance ◽  
Time History ◽  
Element Model ◽  
Nonlinear Time History Analysis ◽  
Promising Alternative ◽  
Demand Models ◽  
Rocking Foundations

AbstractCostal bridge systems usually contain tall piers with heights over 40 m, due to the engineering site exposed to deep water circumstances. Note that the conventional seismic isolation devices (e.g., isolation bearings) are not that effective for tall piers, since their dynamic performance is significantly affected by the distributed mass and vibration modes of columns; therefore, base isolation design philosophy could be a promising alternative for mitigating seismic demands of this type of bridges. This paper mainly investigates the efficiency of rocking foundations in improving seismic performance of tall pier bridges, with the results presented in the format of fragility curves. Finite element model of the prototype tall pier bridge is developed, and the responses subjected to near-fault motions are obtained using nonlinear time history analysis. Probability seismic demand models and fragility curves are then developed accordingly, based on which the performance of tall pier bridges are assessed. The results show that employment of rocking foundations could significantly reduce the demands of tall piers and the probability of being damaged. Before the initiation of uplifting at pier base, the behavior of rocking piers resembles that of conventional ones with integrated foundation. While rocking initiates under strong excitations, the demands of rocking piers reduce drastically compared with integrated ones and tend to be similar under different motions, which benefits the post-earthquake performance assessment of these bridges.

scholarly journals Mathematical Modeling of Linear Static and Dynamic Analysis for Pier Height Effect on the Structural Performance of Bridges Structures

2021 ◽  
Vol 8 (4) ◽  
pp. 617-625
Author(s):  
Ali Fadhil Naser ◽  
Hussam Ali Mohammed ◽  
Ayad Ali Mohammed
Keyword(s):  
Time History ◽  
Bending Moment ◽  
High Strength ◽  
Response Spectra ◽  
Structural Performance ◽  
Static And Dynamic Analysis ◽  
Compressive Stresses ◽  
History Analysis ◽  
Negative Bending ◽  
Dynamic Frequency

The results of linear static analysis explained that the increasing of pier heights was leaded to rise the values of positive bending moment, tensile stresses, and downward vertical deflection. Whereas the compressive stresses and negative bending moment were decreased, indicating that the structural performance of bridge structure representing by stiffness, bearing capacity of structural members, and elasticity will decrease and the bridges structures will be damaged. Therefore, the bridges structures need safe design when using tall piers by adopting high quality materials such as high strength concrete, more steel reinforcement, more prestressed tendons, and increasing of cross section dimensions of girders and piers. The results of modal analysis show that the un-loaded dynamic frequency for three types of bridges models were decreased when the pier heights were increased, indicating that the stiffness of bridges structure was became low with higher pier height. According to response spectra and time history analysis results, the loaded dynamic frequency (vibration state) and dynamic displacement were increased when the pier heights were increased, showing that the bridge of structure will suffer from high vibration when the pier height was high. It can be concluded that from this study, the piers heights have significant effects on the static and dynamic structural performance of bridges structures under traffic loads.

Assessment of an old roadway bridge under static and seismic loading conditions

2021 ◽  
Vol 7 (2) ◽  
pp. 107
Author(s):  
Abdulkadir Cüneyt Aydın ◽  
Mehmet Fatih Yılmaz
Keyword(s):  
Service Life ◽  
Negative Impact ◽  
Time History ◽  
Site Investigation ◽  
Element Model ◽  
Detailed Examination ◽  
Railway Transportation ◽  
Railway Bridges ◽  
Earthquake Loads ◽  
Nonlinear Time History

A large proportion of road and railway bridges, present in Turkey served for many years, have been completed their service life or will soon. Continuing safety and sustainability of these bridges under traffic loads have been of great increasing importance to roadway and railway transportation line to be continuous servicing. In addition, the demolition and reconstruction of bridges that have reached the end of their service life or are nearing completion will have a negative impact on the country's economy. All of these requirements' detailed examination of bridges in order to provide economical and safe service, considering current vehicle loads and earthquake loads. The Mahmutçavuş Bridge is investigated as a simply supported continuous composite roadway bridge at this work. The finite-element model of the bridge is constituted by site investigation and measurement. Different truckloads using for the design of the bridge are determined, and static analysis of the bridge is conducted. Seven earthquake records are scaled for two different earthquake design spectrums. The nonlinear time-history analyses are conducted, considering Δ-δ effects. The performance of the bridge for varying truckloads and earthquake loads is investigated, and results are discussed in detail.

Longitudinal Vibration Control of Long-Span Railway Cable-Stayed Bridge

2011 ◽  
Vol 255-260 ◽  
pp. 1795-1799
Author(s):  
De Shan Shan ◽  
Yuan He ◽  
Li Qiao
Keyword(s):  
Vibration Control ◽  
Longitudinal Vibration ◽  
Time History ◽  
Bending Moment ◽  
Element Model ◽  
Viscous Dampers ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Two Parameters ◽  
Main Girder

As the floating type cable-stayed bridge has no longitudinal constraint between the main girder and the pylon, it may cause the main girder a large longitudinal displacement and the root of tower a large longitudinal bending moment, and affect the normal use and safety of the bridge under the earthquake or the train braking. It is an important part of the design to select an appropriate vibration control scheme. Taking a long-span railway bridge for example, this paper build the finite element model and analyses the damping effect in the view of train braking, moreover, the present study also examines the dynamic behavior with focus on two parameters of damping coefficient C and damping exponent αof the viscous dampers through dynamic time-history analysis. The results show that setting viscous dampers with the reasonable parameters can reduce the vibration and the response of the bridge by train braking and have a good energy dissipation effect.

The Influence of near-Fault Ground Motions on the Seismic Response of Reinforced Concrete Frame

2011 ◽  
Vol 90-93 ◽  
pp. 2633-2639
Author(s):  
Chang Hao Zhang ◽  
Wei Wang ◽  
Hu Wang ◽  
Xun Tao Wang
Keyword(s):  
Reinforced Concrete ◽  
Ground Motion ◽  
Ground Motions ◽  
Time History ◽  
Far Field ◽  
Base Shear ◽  
Reinforced Concrete Frame ◽  
Structural Dynamic ◽  
Concrete Frame ◽  
Near Fault

This paper examined the engineering characteristics of the near-fault ground motion. The four-story reinforced concrete frame was designed under Code for seismic design of building (GB50011-2010).The SAP2000 software was applied to model it, and the nonlinear time history analyses of structure were implemented. Near-fault ground motions with forward directivity and fling-step and far field ground motions were selected as seismic inputs．The results show that in terms of some structural dynamic response parameters, such as the vertex displacement, between the corner of the layer displacement, and the base shear et al., the structural responses to the ground motion with near-fault are increased by considerable magnitudes when the seismic responses of structures step into the elastic-plastic stage, compared with far-field ground motion, and the influence of damaging the mid-lower structure is significantly greater.

Seismic Analysis of Reinforced Concrete Rib Arch Bridge

2012 ◽  
Vol 256-259 ◽  
pp. 1496-1502 ◽  
Author(s):  
Da Lin Hu ◽  
Tian Qi Qu ◽  
Hong Bin Wang ◽  
Long Gang Chen
Keyword(s):  
Reinforced Concrete ◽  
Seismic Response ◽  
Ground Motion ◽  
Seismic Analysis ◽  
Element Model ◽  
Structural Dynamic ◽  
Arch Bridge ◽  
Internal Forces ◽  
Arch Bridges ◽  
Horizontal Ground Motion

There are few researches on seismic response of reinforced concrete rib arch bridges at present; therefore, it is necessary to analyze seismic performance of this kind of bridges. Based on the engineering background of a three-span reinforced concrete rib arch bridge, a full bridge finite element model is built to analyze the structural dynamic characteristic and seismic response of the bridge. The internal forces and displacements of each key section is compared and discussed when the bridge is excited by horizontal unidirectional ground motion or the combination of vertical and horizontal ground motion. The structural seismic response calculated with different analysis methods is compared. The research results of this study can be used as a reference for the seismic design of similar bridges.

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