Dynamic Responses of a Simply Supported Bridge to Moving Vehicle Loads

2011 ◽  
Vol 117-119 ◽  
pp. 231-235 ◽  
Author(s):  
Jeng Hsiang Lin
Keyword(s):  
Time Domain ◽  
Analytical Approach ◽  
Dynamic Responses ◽  
Integral Approach ◽  
Convolution Integral ◽  
Moving Vehicle ◽  
Simply Supported ◽  
Vehicle Loads ◽  
Axle Loads ◽  
Good Agreement

The estimation of dynamic responses of a bridge under vehicle loads moving along the bridge is frequently a problem of great interest for bridge engineers. Presented herein is an analytical approach to estimate the dynamic responses of a simply supported Euler-Bernoulli bridge under a set of vehicle axle loads moving along the bridge at constant speed. The approach involves convolution of the vehicle axle loads with modal responses of the bridge. The convolution integral is solved in time domain by a numerical integral approach. The solution was verified and good agreement was found.

Analysis of Horizontal Reactions Due to Moving Vehicle Loads in Curved Bridges with Varied Support Conditions

2005 ◽  
Vol 8 (5) ◽  
pp. 529-545 ◽  
Author(s):  
Sang-Hyo Kim ◽  
Yong-Seon Lee ◽  
Kwang-Yil Cho
Keyword(s):  
Support Systems ◽  
Tangential Direction ◽  
Dynamic Responses ◽  
Radius Of Curvature ◽  
Moving Vehicle ◽  
Curved Bridge ◽  
Load Distributions ◽  
Moving Vehicles ◽  
Vehicle Loads ◽  
Support Conditions

A curved bridge can have two different bearing directions: chordal and tangential direction. This may bring differences of load distribution due to moving vehicles and structural behavior of a curved bridge. This study presents a 3D numerical model that can demonstrate the dynamic responses of a curved bridge to moving vehicles more precisely. The dynamic response induced by the centrifugal rolling motion of a vehicle is identified according to the variations of the superelevation and the radius of curvature of the deck. Dynamic characteristics of the curved bridge with the moving vehicle are analyzed under the condition of the support types and two different support systems. In general, while the vehicle is passing over the curved bridge, the negative reaction occurs in the inside of the girder. The final result shows that the support system located outside the girder is more advantageous than other systems, and the characteristics of load distributions differ from the others in the various conditions of support systems.

A MOM-Based Algorithm for Identification of Moving Vehicle Loads on Bridges

2006 ◽  
Author(s):  
L. Yu ◽  
T. H. T. Chan ◽  
J. H. Zhu ◽  
M. Z. Chen
Keyword(s):  
Time Domain ◽  
Basis Functions ◽  
Time Domain Method ◽  
Acceptable Solution ◽  
Force Identification ◽  
Moving Vehicle ◽  
Moving Force ◽  
Vehicle Loads ◽  
Ill Conditioning ◽  
Bridge Responses

An improved time domain method (ITDM) is proposed for moving force identification using bridge responses, which aims at an acceptable solution to the ill-conditioning problem that often exists in the inverse problem of moving force identification. Based on the method of moments (MOM) and the theory of moving force identification, the moving forces were described as a combination of whole basis functions, such as orthogonal Legendre polynomials or Fourier series, and were then estimated by solving the new system equations developed based on the basis functions. Under a number of response combination cases, the moving vehicle loads are identified using the ITDM and compared with the existing time domain method (TDM). Further a laboratory study was conducted to evaluate the effect of various parameters on the ITDM. Those parameters include basis function number, mode number, number of measured stations, and CPU executive time of the ITDM. Simulation and experiment results show that the ITDM has higher identification accuracy and robust noise immunity as well as being able to generate an acceptable solution to the ill-conditioning problem to some extent when it is used to identify the moving forces from bridge responses. Meanwhile, the ITDM can lessen the executive CPU time as well as being more flexible when compared with the TDM. This is beneficial to real time analysis of moving force identification in field.

Moving Axle Load From Multi-Span Continuous Bridge: Laboratory Study

2006 ◽  
Vol 128 (4) ◽  
pp. 521-526 ◽  
Author(s):  
Tommy H.T. Chan ◽  
Demeke B. Ashebo
Keyword(s):  
Laboratory Study ◽  
Bending Moment ◽  
Identification Accuracy ◽  
Bottom Surface ◽  
Moving Loads ◽  
Moving Vehicle ◽  
Moving Force ◽  
Computation Efficiency ◽  
Axle Loads ◽  
Good Agreement

Laboratory study on the identification of moving vehicle axle loads on a multi-span continuous bridge from the measured bending moment responses is presented. A bridge-vehicle system model was fabricated in the laboratory. The bridge was modeled as a three span continuous beam and the car was modeled as a vehicle model with two-axle loads. A number of strain gauges were adhered to the bottom surface of the beam to measure the bending moment responses. Using measured bending moment responses as an input, the corresponding inverse problem was solved to identify moving loads. The moving forces were identified when considering bending moment responses from all spans of the beam. In order to avoid the lower identification accuracy around the inner supports of continuous bridge and to improve the computation efficiency, the moving force identification from the target (one selected) span of the continuous bridge was studied. The rebuilt responses were reconstructed from the identified loads as a forward problem. To study the accuracy of the method the relative percentage errors were calculated with respect to the measured and the rebuilt bending moment responses. The rebuilt bending moment responses obtained from the identified forces are in good agreement with the measured bending moment responses. This indirectly shows that the method is capable of identifying moving loads on continuous supported bridges.

Effective Pre-Stress Identification for a Simply-Supported PRC Bridge Based on the Dynamic Response Induced by the Passing Vehicle

2012 ◽  
Vol 430-432 ◽  
pp. 1320-1325
Author(s):  
Jian Qing Bu ◽  
Hai Yun Wang
Keyword(s):  
Dynamic Responses ◽  
Simulation Studies ◽  
Euler Beam ◽  
Direct Derivation ◽  
Moving Vehicle ◽  
Simply Supported ◽  
Beam Elements ◽  
Road Surface Roughness ◽  
Derivation Method ◽  
Beam Bridge

A new method is proposed to identify the bridge effective pre-stress from the dynamic responses induced by the vehicle moving on a simply-supported beam bridge with eccentric straight pre-stress, based on the sensitivity analysis. The bridge is modeled as Euler beam elements and the moving vehicle is modeled as a two-degree freedom system with five parameters. After calculating dynamic responses of the bridge by vehicle-bridge coupled vibration analysis, the dynamic responses sensitivity can be obtained by using the direct derivation method, and the regularization method is adopted to identify the effective pre-stress. The effects on the identified results from different responses, different measuring locations and different road surface roughness are considered in the numerical simulations. The simulation studies indicate that the proposed method can be used to identify the effective pre-stress accurately and effectively for a simply-supported PRC beam bridges.

scholarly journals Research on the Dynamic Responses of Simply Supported Horizontal Pipes Conveying Gas-Liquid Two-Phase Slug Flow

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 83
Author(s):  
Gang Liu ◽  
Zongrui Hao ◽  
Yueshe Wang ◽  
Wanlong Ren
Keyword(s):  
Slug Flow ◽  
Peak Frequency ◽  
Dynamic Responses ◽  
Piping System ◽  
Transverse Displacement ◽  
Vibration Acceleration ◽  
Two Phase ◽  
Horizontal Pipes ◽  
Simply Supported ◽  
Superficial Gas Velocity

The dynamic responses of simply supported horizontal pipes conveying gas-liquid two-phase slug flow are explored. The intermittent characteristics of slug flow parameters are mainly considered to analyze the dynamic model of the piping system. The results show that the variations of the midpoint transverse displacement could vary from periodic-like motion to a kind of motion whose amplitude increases as time goes on if increasing the superficial gas velocity. Meanwhile, the dynamic responses have certain relations with the vibration acceleration. By analyzing the parameters in the power spectrum densities of vibration acceleration such as the number of predominant frequencies and the amplitude of each peak frequency, the dynamic behaviors of the piping system like periodicity could be calculated expediently.

Dynamic Response of the Spectral Element Model by Using the FFT

2007 ◽  
Vol 345-346 ◽  
pp. 845-848
Author(s):  
Joo Yong Cho ◽  
Han Suk Go ◽  
Usik Lee
Keyword(s):  
Fourier Transforms ◽  
Initial Conditions ◽  
Element Model ◽  
Spectral Element ◽  
Dynamic Responses ◽  
Analysis Method ◽  
Euler Beam ◽  
Exact Analytical Solutions ◽  
Simply Supported ◽  
Spectral Analysis Method

In this paper, a fast Fourier transforms (FFT)-based spectral analysis method (SAM) is proposed for the dynamic analysis of spectral element models subjected to the non-zero initial conditions. To evaluate the proposed SAM, the spectral element model for the simply supported Bernoulli-Euler beam is considered as an example problem. The accuracy of the proposed SAM is evaluated by comparing the dynamic responses obtained by SAM with the exact analytical solutions.

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