Wind-Induced Performance of Long-Span Bridge with Modified Cross-Section Profiles by Stochastic Traffic

2014 ◽  
Vol 548-549 ◽  
pp. 1753-1757
Author(s):  
Jun Wu
Keyword(s):  
Wind Tunnel ◽  
Cross Section ◽  
Dynamic Loads ◽  
Dynamic Interactions ◽  
Buffeting Response ◽  
Long Span ◽  
Long Span Bridge ◽  
Fatigue Damage Accumulation ◽  
Section Model ◽  
The Impact

The presence of traffic on a slender long-span bridge (SLB) deck has two types of primary impacts: (1) modification of the bridge cross-section profiles, which may influence the flutter derivatives and in turn, wind-induced aeroelastic loads acting on the bridge; and (2) additional dynamic loads acting on the bridge including dynamic interactions from the vehicles. As compared to the investigations on the impact of traffic as external dynamic loads, those on the impact from the modification of bridge cross-section profiles are rather rare. A scaled bridge section model with vehicle models distributed on the bridge section has been tested in the wind tunnel laboratory. With the FDs obtained from the wind tunnel experiments of various modified bridge cross-section profiles by stochastic traffic, the present study is to numerically evaluate the impact on the wind-induced performance of the long-span bridge, such as the buffeting response and fatigue damage accumulation.

Super-long span bridge aerodynamics: on-going results of the TG3.1 benchmark test – Step 1.2

2019 ◽  
Author(s):  
Giorgio Diana ◽  
Stoyan Stoyanoff ◽  
Andrew Allsop ◽  
Luca Amerio ◽  
Tommaso Argentini ◽  
...  
Keyword(s):  
Numerical Models ◽  
Experimental Tests ◽  
Numerical Comparison ◽  
Aeroelastic Stability ◽  
Turbulent Wind ◽  
Long Span Bridges ◽  
Buffeting Response ◽  
Long Span ◽  
Long Span Bridge ◽  
Sectional Model

<p>This paper is part of a series of publications aimed at the divulgation of the results of the 3-step benchmark proposed by the IABSE Task Group 3.1 to define reference results for the validation of the software that simulate the aeroelastic stability and the response to the turbulent wind of super-long span bridges. Step 1 is a numerical comparison of different numerical models both a sectional model (Step 1.1) and a full bridge (Step 1.2) are studied. Step 2 will be the comparison of predicted results and experimental tests in wind tunnel. Step 3 will be a comparison against full scale measurements.</p><p>The results of Step 1.1 related to the response of a sectional model were presented to the last IABSE Symposium in Nantes 2018. In this paper, the results of Step 1.2 related to the response long-span full bridge are presented in this paper both in terms of aeroelastic stability and buffeting response, comparing the results coming from several TG members.</p>

Numerical Simulation of Wind-Driven Rain on a Long-Span Bridge

2019 ◽  
Vol 19 (12) ◽  
pp. 1950149
Author(s):  
Shenghong Huang ◽  
Qiusheng Li ◽  
Man Liu ◽  
Fubin Chen ◽  
Shun Liu
Keyword(s):  
Numerical Simulation ◽  
Wind Engineering ◽  
Multiphase Model ◽  
Rain Intensity ◽  
Long Span Bridges ◽  
Long Span ◽  
Long Span Bridge ◽  
Extreme Rain ◽  
Section Model ◽  
Bridge Spans

Wind-driven rain (WDR) and its interactions with structures is an important research subject in wind engineering. As bridge spans are becoming longer and longer, the effects of WDR on long-span bridges should be well understood. Therefore, this paper presents a comprehensive numerical simulation study of WDR on a full-scale long-span bridge under extreme conditions. A validation study shows that the predictions of WDR on a bridge section model agree with experimental results, validating the applicability of the WDR simulation approach based on the Eulerian multiphase model. Furthermore, a detailed numerical simulation of WDR on a long-span bridge, North Bridge of Xiazhang Cross-sea Bridge is conducted. The simulation results indicate that although the loads induced by raindrops on the bridge surfaces are very small as compared to the wind loads, extreme rain intensity may occur on some windward surfaces of the bridge. The adopted numerical methods and rain loading models are validated to be an effective tool for WDR simulation for bridges and the results presented in this paper provide useful information for the water-erosion proof design of future long-span bridges.

Research on the Wind Tunnel Force Balance Tests of Long-Span Closed Coal Trestle

2013 ◽  
Vol 477-478 ◽  
pp. 797-802
Author(s):  
Shu Liang Wang ◽  
Shu Guo Liang ◽  
Liang Hao Zou ◽  
Xiang Yang Zhou
Keyword(s):  
Wind Tunnel ◽  
Bridge Deck ◽  
Force Balance ◽  
Mean Values ◽  
Long Span ◽  
Balance Tests ◽  
Section Model ◽  
Base Forces ◽  
Experimental Values ◽  
High Flexibility

Structures with long span and high flexibility are very sensitive to the wind forces, so it is necessary to study on the wind effects on such structures. In this paper, based on section model wind tunnel high-frequency force balance tests, two horizontal base bending moments and shear forces of the typical supporting columns as well trestle bridge deck of the closed coal trestle under different wind directions were measured. The shape coefficients and their variations with the wind directions of the typical supporting columns as well trestle bridge deck were calculated then analyzed by the mean values of base forces. The experimental values of the shape coefficients were compared with those in the Chinese Load Code, the results shown that both were in good agreement, which verified the reliability of the test, which also illustrated that wind-resistant design of the coal trestle in accordance with the Code was reasonable. Based on analysis of the variances of base forces between overall model with and without surrounding buildings, influences of surroundings buildings were studied. Interference factors were proposed which provided the basis for the base forces checking and wind-resistant design of the long-span closed coal trestle structures.

scholarly journals PROCEDURE AND ALGORITHM FOR DETERMINING THE COEFFICIENT OF THE FREIGHT WAGON STABILITY IN COMPLIANCE WITH CURRENT REQUIREMENTS

2021 ◽  
pp. 31-53
Author(s):  
Oleksandr Safronov ◽  
◽  
Andrii Sulym ◽  
Pavlo Khozia ◽  
Yurii Vodiannikov ◽  
...  
Keyword(s):  
Equivalent Stress ◽  
Safety Margin ◽  
Dynamic Loads ◽  
Railway Track ◽  
Longitudinal Impact ◽  
Voltage Amplitude ◽  
Maximum Discharge ◽  
Fatigue Damage Accumulation ◽  
The Impact ◽  
Freight Wagons

Improving the reliability of test results is achieved by applying more advanced methods of recording and processing the results. Therefore, an important part of the study of the strength of freight wagons is the choice of methods for obtaining, processing and analyzing experimental data. The article outlines the procedure and algorithms for determining the equivalent stresses under longitudinal and dynamic loads acting during operation. It is shown that algorithms for determining stresses generated by dynamic longitudinal and vertical forces are significantly different due to various load application schemes. Thus, the testing of freight wagons under dynamic longitudinal loads is carried out by the impact against an experimental wagon, and testing under dynamic vertical forces is performed during the wagon motion in the composition of the experimental train on the characteristic, pre-selected (planned) sections of the railway track at specified speeds. To estimate the level of loading of the freight wagon structureunder vertical dynamic loads, a method based on the replacement of a real random process is used by some schematized process, which in terms of the fatigue damage accumulation should be equivalent to a real process. From the whole variety of schematic methods, two methods stand out, i.e., the full cycle method and the rainflow method, which most fully represent the real process.The advantage of the rainflow method is the ability to process the process in real time. However, the algorithm of the rainflow method is quite complicated and does not allow processing large amounts of information. In this regard, a method of maximum discharge was proposed, which is a kind of full cycles method and allows you to process an unlimited amount of information online. An example specified in GOST 25.101 was used for a comparative analysis of the rainflow and maximum discharge methods. Analysis showed a satisfactory matching of both methods. Based on the procedure outlined, the block structure of the computational process is proposed to determine the equivalent reduced voltage amplitude. Each block displays the impact of the forces depending on the loading condition, that is, longitudinal impact force and dynamic forces when the wagon is moving on straight track sections, curves and switches of the railway track. Key words: wagon car, process, dynamic load, longitudinal load, voltage, amplitude, algorithm, equivalent stress, safety margin, strength.

scholarly journals Steady-Suction-Based Flow Control of Flutter of Long-Span Bridge

2020 ◽  
Vol 10 (4) ◽  
pp. 1372
Author(s):  
Jian Zhan ◽  
Hongfu Zhang ◽  
Zhiwen Liu ◽  
Huan Liu ◽  
Dabo Xin ◽  
...  
Keyword(s):  
Flow Control ◽  
Bridge Deck ◽  
Control Method ◽  
Control Device ◽  
Maximal Increase ◽  
Long Span ◽  
Suction Control ◽  
Long Span Bridge ◽  
Bridge Model ◽  
Section Model

The present wind tunnel study focuses on the effects of the steady-suction-based flow control method on the flutter performance of a 2DOF bridge deck section model. The suction applied to the bridge model was released from slots located at the girder bottom. The suction rates of all slots along the span were equal and constant. A series of test cases with different combinations of suction slot positions, suction intervals, and suction rates were studied in detail for the bridge deck model. The experimental results showed that the steady-suction-based flow control method could improve the flutter characteristics of the bridge deck with a maximal increase in the critical flutter speed of up to 10.5%. In addition, the flutter derivatives (FDs) of the bridge deck with or without control were compared to investigate the fundamental mechanisms of the steady-suction-based control method. According to the results, installing a suction control device helps to strengthen aerodynamic damping, which is the primary cause for enhanced flutter performance of bridge decks.

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