scholarly journals Identification and Application of the Aerodynamic Admittance Functions of a Double-Deck Truss Girder

2019 ◽  
Vol 9 (9) ◽  
pp. 1818 ◽  
Author(s):  
Haosu Liu ◽  
Junqing Lei ◽  
Li Zhu
Keyword(s):  
Wind Tunnel ◽  
Turbulent Flows ◽  
Force Measurement ◽  
Wind Tunnel Test ◽  
Element Model ◽  
Fish Bone ◽  
Lateral Direction ◽  
Segment Model ◽  
Long Span ◽  
Unsteady Effect

This paper presents the aerodynamic admittance functions (AAFs) of a double-deck truss girder (DDTG) under turbulent flows. The objective of the investigation is to identify AAFs using a segment model wind tunnel test. All of the wind tunnel tests were based on the force measurement method and conducted in a passive spire-generated turbulent flow. The segment model adopts a typical DDTG section and is tested in the service and construction stages under 0°, 3°, and 5° wind attack angles. Furthermore, a nonlinear expression is put forward to fit the identified AAFs. The buffeting responses of a long-span road-rail cable-stayed bridge are then calculated for both the service and construction stages using an equivalent ‘fish-bone’ finite element model of the DDTG. The unsteady effect of the buffeting force is considered based on quasi-steady buffeting theory using the identified AAFs. The calculated buffeting responses are finally compared with those for two other AAFs (AAF = 1.0 and the Sears function). The results indicate that the traditional AAFs overestimate vibrations in the vertical and torsional directions but underestimate vibrations in the lateral direction. The identified AAFs of the DDTG can be regarded as a reference for wind-resistant designs with similar girder sections.

Study on one Special-Shaped Long-Span Arch Bridge Using Wind Tunnel Test

2010 ◽  
Vol 29-32 ◽  
pp. 370-376
Author(s):  
Fu You Xu ◽  
H.L. Wang ◽  
Zhe Zhang ◽  
Cai Liang Huang
Keyword(s):  
Wind Tunnel ◽  
Turbulent Flows ◽  
Wind Tunnel Test ◽  
Maximum Amplitude ◽  
Attack Angle ◽  
Torsional Stiffness ◽  
Aerodynamic Stability ◽  
Arch Bridge ◽  
Long Span ◽  
Bridge Model

Study on wind-resistant performance of one special-shaped long-span arch bridge is carried out using a full-bridge aeroelastic model with a scale of 1:66 in wind tunnel test. The tests on vortex-induced vibration (VIV for short), buffeting and aerodynamic stability of both bare arch and full-bridge are comprehensively conducted in smooth and turbulent flows with attack angle of -3º, 0º, 3º, and yaw angles ranging from 0º to 180º with a step of 15º. The results show that the first-order symmetric VIV of vertical bending appears on the bare arch in smooth flow with attack angle of -3º, 0º, 3º, and yaw angle of 0º, 5º. The maximum amplitude of VIV at 1/4 section of the bare arch is close to 30cm, higher than the corresponding value at the crown section. No stable VIV is observed on full-bridge model tests in both smooth and turbulent flows. For full-bridge model in turbulent flows, both means and standard deviations of girder torsional displacement at 1/2 and 1/4 sections are very small, which prove that the bridge integral torsional stiffness is significantly improved due to the 3-D cable-support system. The bridge possesses good aerodynamic stability for both bare arch and full-bridge service states.

Wind-Induced Responses Study and Wind-Resistant Design of Super-Long-Span Cable-Membrane Roof Structure of Shenzhen Baoan Stadium

2011 ◽  
Vol 71-78 ◽  
pp. 666-672
Author(s):  
Wen Bo Sun ◽  
Qing Xiang Li ◽  
Han Xiang Chen ◽  
Wei Jian Zhou
Keyword(s):  
Numerical Calculation ◽  
Wind Tunnel ◽  
Dynamic Response ◽  
Membrane Structure ◽  
Wind Tunnel Test ◽  
Scale Model ◽  
Induced Responses ◽  
Design Codes ◽  
Long Span ◽  
Roof Structure

In this paper, the system and the design philosophy of wheel-spoke cable-membrane structure of Baoan Stadium is introduced firstly. And then the study of wind tunnel test on 1:250 scale model is mainly presented, together with the numerical calculation of the wind dynamic response. Finally, the wind-resistant design of the roof structure based on the results of wind tunnel test and the foreign design codes is generally introduced.

Comparative Analysis on Aerostatic Coefficients of Bridge Deck Based on Wind Tunnel Test

2010 ◽  
Vol 29-32 ◽  
pp. 377-382
Author(s):  
Fu You Xu ◽  
Bin Bin Li ◽  
Cai Liang Huang ◽  
Zhe Zhang
Keyword(s):  
Comparative Analysis ◽  
Wind Tunnel ◽  
Working Conditions ◽  
Turbulence Intensity ◽  
Flow Separation ◽  
Bridge Deck ◽  
Force Measurement ◽  
Wind Tunnel Test ◽  
Microscopic Mechanism ◽  
Comprehensive Study

A comprehensive study of force measurement test in wind tunnel is conducted for the streamlined deck model of Dalian Cross-sea Bridge scheme. The factors, including stacking load in erection, vehicles arrangement, central slot and so on, are analyzed in terms of the influence of the three-component coefficient in the way of microscopic mechanism. The stall angles under different working conditions are also investigated. The results show that stacking loads and vehicle arrangement barely have any impact on the three-component coefficient, which can be neglected approximately; lift and pitching coefficients decrease for the slotted deck, and the slot width has little influence on the aerostatic coefficients; bridge railing, stacking loads and vehicles change the flow separation and re-attachment around the deck, increasing the turbulence intensity, leading to the fluctuation of stall angles.

The Static Wind Load Research of a Flat Box Girder Based on the Numerical Wind Tunnel

2013 ◽  
Vol 351-352 ◽  
pp. 410-414
Author(s):  
Nan Li ◽  
Ji Xin Yang
Keyword(s):  
Wind Tunnel ◽  
Flow Field ◽  
Wind Field ◽  
Wind Tunnel Test ◽  
Box Girder ◽  
Long Span ◽  
Long Span Bridge ◽  
Tunnel Technique ◽  
Aerodynamic Parameters ◽  
Good Agreement

In this paper, the wind field around the flat box girder of a long-span bridge under 0o attack angle was investigated by the numerical wind tunnel technique, which can not only get the distributions of the pressure, velocity and vortex in the flow field, but also obtain the various aerodynamic parameters of the bridges. The velocity profiles were obtained, and the coefficient of tri-component from the numerical simulations was in good agreement with that from the wind tunnel test, which demonstrated that it was reliable and feasible to utilize the numerical wind tunnel technique to simulate the wind field and certificate the coefficient of tri- component of the bridge.

Test Research on Aerodynamic Interference Effect on Aerostatic Coefficients of Main Beam in Parallel Bridge

2012 ◽  
Vol 178-181 ◽  
pp. 2131-2134
Author(s):  
Jie Wang ◽  
Jian Xin Liu
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Wind Tunnel Test ◽  
Lateral Force ◽  
Main Beam ◽  
Interference Effects ◽  
Force Coefficient ◽  
Long Span ◽  
Rigid Frame ◽  
Aerodynamic Interference

Against the problem of the aerodynamic interference effects on aerostatic coefficients between parallel continuous rigid frame bridges with high-pier and long-span, the aerodynamic interference effects on aerostatic coefficients of main beam in the parallel long-span continuous rigid frame bridges were investigated in details by means of wind tunnel test. The space between the two main beams and wind attack angles were changed during the wind tunnel test to study the effects on aerodynamic interferences of aerostatic coefficients of main beam. The test got aerostatic coefficients of 10 conditions. The research results have shown that the aerodynamic interference effects on aerostatic coefficients of main beam in parallel bridges can not be ignored. The aerodynamic interference effects on parallel bridge main beam is shown mainly as follows: The drag coefficient of main beam downstream dropped and the drag coefficient of main beam upstream changed but not change significantly. There are also the aerodynamic interference effects of lateral force coefficient and torque coefficient between the main beams upstream and downstream. The effects upstream are smaller and the effects downstream are larger.

Study on Static Wind Loading Coefficients of Suspension Bridge Based on CFD Simulation and Wind Tunnel Test

2011 ◽  
Vol 66-68 ◽  
pp. 334-339
Author(s):  
Mei Yu ◽  
Hai Li Liao ◽  
Ming Shui Li ◽  
Cun Ming Ma ◽  
Nan Luo ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Cfd Simulation ◽  
Wind Tunnel Test ◽  
Suspension Bridge ◽  
Wind Load ◽  
Dynamics Simulation ◽  
Wind Loading ◽  
Suspension Bridges ◽  
Long Span ◽  
Section Model

Long-span suspension bridges, due to their flexibility and lightness, are much prone to the wind loads, aerodynamics performance has become an important aspect of the design of long-span suspension bridges. In this study, the static wind load acting on the suspension bridge during erection has been investigated through wind tunnel test and numerical analysis. The wind tunnel test was performed using a 1:50 scale section model of the bridge, the static wind load acting on the section model was measured with varying attack angles. Numerical method used here was computational fluid dynamics simulation, a two-dimensional model is adopted in the first stage of the analysis, then the SIMPLE algorithm was employed to solve the governing equations. The analytical results were compared with the wind tunnel test data, it was shown from the study that the results of CFD simulation was good agreement with that of the wind tunnel test.

Experimental Study of the Nonlinear Torsional Flutter of a Long-Span Suspension Bridge with a Double-Deck Truss Girder

2021 ◽  
pp. 2150102
Author(s):  
Ming Li ◽  
Yanguo Sun ◽  
Yongfu Lei ◽  
Haili Liao ◽  
Mingshui Li
Keyword(s):  
Wind Tunnel ◽  
Model Test ◽  
Wind Tunnel Test ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Nonlinear Flutter ◽  
Long Span ◽  
Aeroelastic Model ◽  
Flutter Analysis ◽  
Section Model

The purpose of this study is to investigate the nonlinear torsional flutter of a long-span suspension bridge with a double-deck truss girder. First, the characteristics of nonlinear flutter are studied using the section model in the wind tunnel test. Different aerodynamic measures, e.g. upper and lower stabilizers and horizontal flaps, are applied to improve the flutter performance of the double-deck truss girder. Then, the full bridge aeroelastic model is tested in the wind tunnel to further examine the flutter performance of the bridge with the optimal truss girder. Finally, three-dimensional (3D) flutter analysis is performed to study the static wind-induced effects on the nonlinear flutter of the long-span suspension bridge. The results show that single-degree-of-freedom torsional limit cycle oscillations occur at large amplitudes for the double-deck truss section at the attack angles of [Formula: see text] and [Formula: see text]. The upper and lower stabilizers installed on the upper and lower decks, respectively, and the flaps installed near the bottoms of the sidewalks can all effectively alleviate the torsional flutter responses. Meanwhile, it is found that the torsional flutter responses of the truss girder in the aeroelastic model test are much smaller than those in the section model test. The 3D flutter analysis demonstrates that the large discrepancies between the flutter responses of the two model experiments can be attributed to the additional attack angle caused by the static wind-induced displacements. This finding highlights the importance and necessity of considering the static wind-induced effects in the flutter design of long-span suspension bridges.

scholarly journals Research on Snow Load Characteristics on a Complex Long-Span Roof Based on Snow–Wind Tunnel Tests

2019 ◽  
Vol 9 (20) ◽  
pp. 4369 ◽  
Author(s):  
Guolong Zhang ◽  
Qingwen Zhang ◽  
Feng Fan ◽  
Shizhao Shen
Keyword(s):  
Wind Tunnel ◽  
Basic Characteristic ◽  
Wind Tunnel Test ◽  
Experimental System ◽  
Similarity Criteria ◽  
Wind Tunnel Tests ◽  
Snow Load ◽  
Long Span ◽  
Characteristic Modes ◽  
Snow Distribution

A considerable number of studies have been carried out for predicting snowdrifts on roofs over the years. However, few studies have focused on snowdrifts on complex long-span roofs, as the complex shape and fine structure pose significant challenges. In this study, to simplify the calculation requirements of snow load on such roofs, work was conducted to decompose the snowdrift on a complex roof into snowdrifts on several simple roofs. First, the snow–wind tunnel test similarity criteria were investigated based on a combined air–snow–wind experimental system. Thereafter, with reference to the validated experimental similarity criteria, a series of snow–wind tunnel tests were performed for snowdrifts on a complex long-span structure under the conditions of different inflow directions. Finally, based on empirical orthogonal function (EOF) analysis, the snowdrifts on the complex roof were decomposed into basic characteristic distribution modes, including snowdrifts caused by the local and overall roof forms. The snow distribution under a specific inflow direction could be derived from the weighted combination of the basic characteristic modes, based on the wind direction coefficients. Therefore, it is possible for the snow load on a complex roof to be estimated preliminarily based on the snow distributions on several simple roofs.

Sign in / Sign up

Export Citation Format

Share Document