scholarly journals Evaluation on Impact Interaction between Abutment and Steel Girder Subjected to Nonuniform Seismic Excitation

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Yue Zheng ◽  
Xiang Xiao ◽  
Lunhai Zhi ◽  
Guobo Wang
Keyword(s):  
Reinforced Concrete ◽  
Seismic Excitation ◽  
Fe Model ◽  
Steel Girder ◽  
Perfectly Plastic ◽  
Impact Interaction ◽  
Girder Bridge ◽  
Steel Box Girder Bridge ◽  
Rubber Bearings ◽  
The Impact

This paper aims to evaluate the impact interaction between the abutment and the girder subjected to nonuniform seismic excitation. An impact model based on tests is presented by taking material properties of the backfill of the abutment into consideration. The conditional simulation is performed to investigate the spatial variation of earthquake ground motions. A two-span continuous steel box girder bridge is taken as the example to analyze and assess the pounding interaction between the abutment and the girder. The detailed nonlinear finite element (FE) model is established and the steel girder and the reinforced concrete piers are modeled by nonlinear fiber elements. The pounding element of the abutment is simulated by using a trilinear compression gap element. The elastic-perfectly plastic element is used to model the nonlinear rubber bearings. The comparisons of the pounding forces, the shear forces of the nonlinear bearings, the moments of reinforced concrete piers, and the axial pounding stresses of the steel girder are studied. The made observations indicate that the nonuniform excitation for multisupport bridge is imperative in the analysis and evaluation of the pounding effects of the bridges.

Study on Influence of Excavation of Metro Station on a Steel Box Girder Bridge

2013 ◽  
Vol 427-429 ◽  
pp. 209-215
Author(s):  
Lei Yang ◽  
Kai Feng Zheng ◽  
Jin Zhu
Keyword(s):  
Local Stress ◽  
Fe Model ◽  
Steel Girder ◽  
Box Girder ◽  
Metro Station ◽  
Finite Element Software ◽  
Steel Box Girder ◽  
Bridge Structures ◽  
Girder Bridge ◽  
Steel Box Girder Bridge

To evaluate the safety of a steel box bridge during the construction of a metro station, the process of excavation which was based on the metro station and its overpass bridge in Chengdu was analyzed. A detailed FE model was established which include the soil, the station and the bridge using general finite element software ALGOR. According to the procedure of the constructing station and completed station, investigating the absolute settlements and differential settlements of the earths surface and foundation in metro station incidence, the effect on the steel box girder overall stress and local stress was analyzed extensively. The results demonstrated that the excavation has a insignificant influence on the deformations and stresses of the steel girder. Thus it provides an important understanding of the interactions of bridge structures and underground constructions.

Applicability of Sub-Modelling Technique for Dynamic Analysis of Concrete Structures With Attached Equipment Under Missile Impact

2020 ◽  
Author(s):  
Genadijs Sagals ◽  
Nebojsa Orbovic ◽  
Thambiayah Nitheanandan
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Behaviour ◽  
Modelling Technique ◽  
Research Centre ◽  
Front Wall ◽  
Fe Model ◽  
Reinforced Concrete Slabs ◽  
Rc Structure ◽  
Impact Area ◽  
The Impact

Abstract This paper describes the work conducted by the Canadian Nuclear Safety Commission (CNSC) related to the numerical simulations of reinforced concrete (RC) structures under deformable missile impact. The current paper is a continuation of the work conducted in the frame of the OECD/NEA* IRIS (Improving Robustness Assessment Methodologies for Structures Impacted by Missiles) Phase 3 benchmark project. The concrete mock-up with two simple structures attached, one welded and another bolted, was built and tested at the VTT Technical Research Centre in Espoo, Finland. This mock-up was impacted by three subsequent missiles with varying velocities in order to obtain the damage accumulation. To examine vibration transmission through the mock-up, the simple structures modelling equipment were attached to the rear wall of the structure, while the missile impact was at the centre of the front wall. The parameters of the missiles and the RC structure were selected to ensure a flexible behaviour of the RC target in the impact area with only moderate damages, specifically cracking and permanent deformation without perforation. The non-linear dynamic behaviour of the reinforced concrete slabs under missile impact was analyzed using the commercial FE code LS-DYNA. A hybrid FE model using both 3-D solid and 2-D shell FE models was developed for the target discretization. Since the ultimate objective of this work is to model the entire structure over long time periods, a simplified combined shell-solid model with distributed (smeared) reinforcement was selected and validated. This model employs solid FE around an impact area and shell FE for the rest of the mock-up. Detailed modelling of a large RC structure with all equipment attached leads to a very large finite element (FE) model. Therefore, two-level FE modelling using sub-modelling approach was employed: first, analyze the vibrations of a reinforced concrete structure with simplified equipment modelling, and second, analyze in detail the equipment connected to it. This approach assumes uncoupled dynamic behaviour of the structure and the equipment. While the sub-modelling technique is commonly used in static analysis, a special sensitivity analysis was conducted to prove the applicability of sub-modelling for impact analysis. Finally, the effect of structural damping was examined and the best possible damping was selected. The selected damping values and sub-models resulted in relatively good agreement with the test results for both global (RC mock-up) and local (equipment) behaviour.

Damage Assessment in Bridges Based on Measured Natural Frequencies

2017 ◽  
Vol 17 (02) ◽  
pp. 1750022 ◽  
Author(s):  
Ivana Mekjavić ◽  
Domagoj Damjanović
Keyword(s):  
Reinforced Concrete ◽  
Damage Assessment ◽  
Structural Damage ◽  
Natural Frequencies ◽  
Reinforced Concrete Beams ◽  
Computational Technique ◽  
Steel Girder ◽  
Damage Scenarios ◽  
Steel Girder Bridge ◽  
Girder Bridge

This paper presents an identification technique for damage assessment of structures where only the information about the changes of measured natural frequencies can be directly utilized. The structural damage is characterized by a local decrease in the stiffness as represented by a scalar reduction of the material modulus. The objective of this study is to investigate the feasibility of using such a technique for identifying the structural damage in a real steel girder bridge. Numerical examples involving damaged reinforced concrete beams are first used to demonstrate the capability of the proposed computational technique, based on the nonlinear perturbation theory, to predict the exact location and severity of the damage. To experimentally validate the theory, laboratory damage detection experiments were performed on a simply supported reinforced concrete beam with various damage scenarios as the example. The results of the damage identification procedure based on the measurement of structure’s frequencies before and after occurrence of the damage show that this method can accurately locate the damage and predict the extent of damage. The method performs well even for a structure with a very serious damage as demonstrated by application of the proposed direct iteration technique to a six-span steel girder bridge. Using a limited number of measured natural frequencies, significant reduction in the stiffness of the bridge at multi-sites is detected.

Effects of Truck Impacts on Bridge Piers

2013 ◽  
Vol 639-640 ◽  
pp. 13-25 ◽  
Author(s):  
Anil K. Agrawal ◽  
Guang Yong Liu ◽  
Sreenivas Alampalli
Keyword(s):  
Static Load ◽  
Impact Resistance ◽  
Bridge Piers ◽  
Steel Girder ◽  
Federal Highway ◽  
Steel Girder Bridge ◽  
Girder Bridge ◽  
Bridge Failure ◽  
Aashto Lrfd ◽  
The Impact

According to Federal Highway Administration, impact by moving trucks is the 3rd leading cause of bridge failure or collapse in the country. Although current AASHTO LRFD Guide Specifications prescribe designing bridge piers by applying a 400 kips static load at a height of 4ft to improve their impact resistance, recent studies have shown that the dynamic forces because of truck impacts may be significantly higher than that recommended by the AASHTO Guide Specifications. In this paper, we present an extensive investigation on the impact of a three-span steel girder bridge with reinforced concrete piers by trucks running at different speeds through models of bridge and the truck in LS-DYNA, including a correlation between seismic and impact resistance of bridge piers. Results also present a comparison between static load prescribed by AASHTO Guide Specifications and dynamic impacts loads observed during numerical simulations. A performance based approach is proposed to design bridge piers against truck impacts.

Seismic Performance Research of Steel Girder Bridge with Isolation Bearings and Restrainer Cables

2013 ◽  
Vol 353-356 ◽  
pp. 2000-2003
Author(s):  
Peng Zhang ◽  
Cui Ping Pang ◽  
Min Yuan ◽  
Wan Wen Wang
Keyword(s):  
Seismic Performance ◽  
Seismic Isolation ◽  
Steel Girder ◽  
Girder Bridges ◽  
Steel Girder Bridges ◽  
Lead Rubber Bearings ◽  
Steel Girder Bridge ◽  
Girder Bridge ◽  
Rubber Bearings ◽  
Existing Bridges

The seismic performance of multi-span simply supported steel-girder bridges with sliding and high rocker steel bearings is poor during earthquakes. During the past 20 years, seismic isolation has emerged as one of the most promising strategy for improving the seismic performance of existing bridges. In this study elastomeric bearings, lead-rubber bearings, and cable restrainers are attempted to modify the seismic response of bridges, and theirs effects are analyzed and compared.

scholarly journals Effect of Cross-Frames on Load Distribution of Steel Bridges with Fractured Girder

2020 ◽  
Vol 5 (4) ◽  
pp. 32 ◽  
Author(s):  
Mohammad Abedin ◽  
Armin B. Mehrabi
Keyword(s):  
Load Distribution ◽  
Steel Plate ◽  
Steel Girder ◽  
Girder Bridges ◽  
Steel Girder Bridges ◽  
Solution Methods ◽  
Profile Changes ◽  
Girder Bridge ◽  
The Impact ◽  
Sudden Collapse

In steel girder bridges, fracture of one girder may occur without noticeable bridge profile changes. It is critical to ensure that the bridge will have adequate capacity to prevent collapse until the next cycle of inspection discovers the damage. It is realized that once one of the bridge girders is fractured, vertical loads need to be distributed through an alternative path to the intact girder(s). In this case, cross-frames can play an important role in transferring the loads and preventing from sudden collapse. This paper investigates the impact of cross-frames on load distribution after a fracture is occurred in one girder. Bridge configurations with different cross-frame spacing were studied using finite element modeling and simulation of the bridge behavior with a fractured steel plate girder. Nonlinear and dynamic solution methods were used for these analyses. Results of this investigation demonstrated the important role cross-frames can play in providing some reserved capacity for the bridge with fractured girder to enhance the bridge redundancy. The contribution of the cross-frames and the behavior of the bridge after fracture in one girder however depends on the configuration of the bridge. A study of the variation of the effect of cross-frames with respect to the number of girders is also included in this paper.

Study on Influence of Temperature to Section Deformation of Steel Box Girder during Cantilever Installation

2013 ◽  
Vol 351-352 ◽  
pp. 114-117
Author(s):  
Zhong San Li ◽  
Jun Qing Lei ◽  
Kun Zhang ◽  
Yun Xiao ◽  
Dao Jin Lin
Keyword(s):  
Temperature Change ◽  
Atmospheric Temperature ◽  
Relative Deformation ◽  
Element Analysis ◽  
Box Girder ◽  
Steel Box Girder ◽  
Flat Steel ◽  
Girder Bridge ◽  
Steel Box Girder Bridge ◽  
The Impact

Because of solar radiation and the atmospheric temperature rise, the temperature change of the steel box girder bridge be larger. Thermal conductivity and sensitivity to the temperature change of steel is very good. The impact of temperature effect can be compared with the dead and live load under certain circumstances. Taking a bridge as example, the relative deformation of flat steel box-shaped girder is analyzed with the finite element analysis software. The results can be reference for other bridges.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

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