FREE ELECTRONIC LIBRARY - Dissertations, online materials

Pages:     | 1 |   ...   | 17 | 18 || 20 |

«A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of ...»

-- [ Page 19 ] --

(b) Investigation of vehicle-bridge-wind system (Chapters 4 and 5) With the modal coupling techniques and hybrid aerodynamic analysis approaches developed in the first part, the vehicle-bridge-wind system is systematically studied in the dissertation. This part covers two consecutive topics: interaction analysis of the coupled system and accident assessment of vehicles. A rational prediction of the performance of the vehiclebridge system under strong winds is of utmost importance to the maximum evacuation efficiency and the safety of vehicles and bridges. Most existent works focus on either wind action on vehicles running on a roadway (not on bridges), wind effect on the bridge without considering vehicles on the bridge, or vehicle-bridge interaction analysis without considering wind effect. A comprehensive vehicle-bridge-wind coupled analysis is very rare.

The present study aims at building a framework for the vehicle-bridge-wind aerodynamic analysis, which will lay a very important foundation for vehicle accident analysis, based on dynamic analysis results, and facilitate the aerodynamic analysis of bridges, considering vehiclebridge-wind interaction. The framework starts with building a general dynamic-mechanical model of a vehicle-bridge-wind coupled system. After the framework is established, a series of 2-axle four-wheel high-sided vehicles on long-span bridges under strong winds are chosen as a numerical example to demonstrate the methodology. With the mechanical model of the vehiclebridge system, dynamic performance of vehicles as well as bridges is studied under strong winds.

Based on the dynamic interaction analysis results, an assessment model for vehicle accidents on bridges and on roads under wind action is introduced. All the existent accident analysis models are only for vehicles on roadways, and dynamic vibrations of the vehicles are not considered. The proposed model starts with a full interaction analysis between the bridge and the vehicle, which predicts, in addition to the bridge vibration, the vehicle response in the directions of vertical, rolling and rotation under the wind action and road roughness. Such vehicle and bridge vibration information is carried over to the following accident analysis of the vehicle only. With given accident criteria, the accident driving speed can then be predicted under

any wind speed. The main conclusions include:


• The proposed accident analysis model can be used to predict the accident-related response. With suggested accident criteria and driving behavior model, the accident risks can be assessed.

• Lowering driving speed is effective in lowering the accident risk only if the wind speed is not extremely high. Setting suitable driving speed limits is important to decrease the likeliness of accident occurrence.

• When wind speed reaches a certain high level, the vehicle should not be on the bridge, no matter what its driving speed. Rational critical wind speed limits should be set to decide when to close the bridge.

• Vehicles on the bridge are more vulnerable to accidents than those on the road. Lower driving speed limits should be set for vehicles on bridges than in the road to avoid accidents when strong wind speed exists.

(c) Mitigation of excessive responses of bridges (Chapters 6-8) Excessive responses of the bridge usually exist when wind speed is high. Under strong winds, modal coupling effects usually become stronger for long-span bridges. It may result in a significant additional component to the buffeting response of each individual mode, compared with cases of weak modal coupling. In addition to the traditional resonant suppression control mechanism of Tuned Mass Dampers, a more efficient control approach may exist for the coupled buffeting control of bridges in strong wind. Approximated closed-form solutions of coupled buffeting response are first derived for a multi-mode coupled bridge system attached with an arbitrary number of TMDs. This derivation clearly shows the contributions of all components of the response and indicates how TMDs can be designed to control each part. Finally, the applicability of dual-objective control with a passive TMD system, based on the new control approach, is briefly discussed.

After the new features of TMD, control on vibrations are studied. Optimal variables of TMDs in the coupled vibration control are numerically studied. The finding in this part verifies the common assumption that single-mode-based control strategy can be used for bridges with well-separated modal frequencies. However, for coupling-prone bridges with low frequency ratio, the control strategy should be based on the analysis of coupled vibrations. Many modern long-span bridges may fall into this category.

As an exploratory application of vibration control for long-span bridges in a hurricane-prone area, a movable vehicle-type of control facility is designed and its efficiency is studied. Placement of movable control system on bridge during evacuation will certainly block traffic and is not a perfect solution. However, it is better than otherwise to completely close bridge in evacuation. In extreme cases, to protect the bridge from being damaged, the movable control system can also be placed on the bridge when the traffic is completely closed. Some issues for practical implementation certainly need to be further addressed.

9.2 Future Work

The writer believes that the following issues deserve further research:


• In the dissertation, determinant results are given to assess the risks of vehicle accidents. However, the driving process of vehicles on the road or on the bridge is actually affected by many uncertain factors, so the reliability-based accident analysis is needed and can be carried out in the future work.

• Wind- and vehicle-induced fatigue is a very important topic. All existent works treat vehicle-induced fatigue and wind-induced fatigue separately. Based on the interaction analysis of the vehicle-bridge-wind system, the combined fatigue problem can be rationally predicted, which is a very interesting direction for future research.

• Vehicle performance on roadways under wind loading deserves more study. In some typical highway locations with various curvatures, slopes, and road surface conditions, vehicles may exhibit different accident-related performance. To envisage the transportation scenario of vehicles from several typical locations of the highway to even the whole highway system in one specific area will give the transportation authorities much valuable information. This is another very promising future direction based on the present study.

• The driver-behavior model, which can be adopted in the accident analysis model, should be improved by adopting statistic approaches, since every driver behaves differently. As a very challenging task, it deserves further study.

• In the dissertation, some temporary approaches with Tuned Mass Dampers are proposed to mitigate the vibration of long-span bridges under strong wind. Some more adaptive and economical ways can be studied, based on more advanced materials and mechanical engineering techniques.

–  –  –

Abe, M. and Fujino, Y. (1994). Dynamic characterization of multiple tuned mass dampers and some design formulas. Earthquake Engineering & Structural Dynamics, 23 (8), 813-835.

Abe, M. and Igusa, T. (1995). Tuned Mass Dampers for structures with closely spaced natural frequencies. Earthquake Engineering & Structural Dynamics, 24 (2), 247-266.

Abdel-Rohman, M. and Leipholz, H. H. (1978). Active Control of Flexible Structures, J. of Structural Division, ASCE, Vol. 104, No. 8 1251-1266.

Adikari, R., and Yamaguchi, H. (1994). Adaptive control of nonstationary wind-induced vibration of tall building, Proc. First World Conf. Structural Control, TA4, 43-52.

Agar, T. (1989). Aerodynamic flutter analysis of suspension bridges by a modal technique, Engineering Structures, 11(2), 75-82.

Amann, O. H., von Karman, T., and Woodruff, G. B. (1941) The failure of Tacoma Narrows Bridge, Federal Works Agency.

Anderson, E.Y. and Pederson, L.(1994). Structural monitoring of the Great Belt East bridges, Proc. of 3rd symposium on strait crossing, ed. Krokeborg, J., Alesund, Norway, 12-15 June, 207-216.

Baker, C. J. (1986). A simplified analysis of various types of wind-induced road vehicle accidents, J. of Wind Engineering and Industrial Aerodynamics, 22, 69-85.

Baker, C. J. (1987). Measures to control vehicle movement at exposed sites during windy periods, J. of Wind Engineering and Industrial Aerodynamics, 25, 151-161.

Baker, C. J. (1991a). Ground vehicles in high cross winds.1. Steady aerodynamic forces, J. of Fluids and Structures, 5, 69-90.

Baker, C. J. (1991b). Ground vehicles in high cross winds.2. Unsteady aerodynamic forces, J. of Fluids and Structures, 5, 91-111.

Baker, C. J. (1991c). Ground vehicles in high cross winds.3. The interaction of aerodynamic forces and the vehicle system, J. of Fluids and Structures, 5, 221-241.

Baker, C. J. (1994). The quantification of accident risk for road vehicles in cross winds, J. of Wind Engineering and Industrial Aerodynamics, 52, 93-107.

Baker, C. J. (1999). The quantification of accident risk for road vehicles in cross winds, J. of Wind Engineering and Industrial Aerodynamics, 52, 93-107.

Baker, C. J. and Reynolds, S. (1992). Wind-induced accidents of road vehicles, Accident Analysis & Prevention, 24, 6, 559-575.

–  –  –

Boonyapinyo, V., Miyata, T. and Yamada, H. (1999). Advanced aerodynamic analysis of suspension bridges by state-space approach, J. of Structural Engineering, ASCE, 125 (12), 1357-1366.

Brancaleoni, F. and Diana, G. (1993). The Aerodynamic Design Of The Messina-Straits Bridge.

J. of Wind Engineering and Industrial Aerodynamics, 48(2-3), 395-409.

Bucher, C. G. and Lin, Y. K. (1988). Stochastic stability of bridges considering coupled modes, J. Engineering Mechanics, ASCE, 114(12), 2055-2071.

Bucher, C. G. and Lin, Y. K. (1989). Stochastic stability of bridges considering coupled modes:

II., J. of Engineering Mechanics, ASCE 115(2), 384-400.

Cai, C. S. (1993). Prediction of long-span response to turbulent wind, Ph. D dissertation, The University of Maryland.

Cai, C. S., and Albrecht, P. (2000). Flutter Derivatives Based Random Parametric Excitation Aerodynamic Analysis, Computers & Structures, Elsevier Science, Ltd, UK, 75(5), 463-477.

Cai, C. S., Albrecht, P., and Bosch, H. R., (1999a). Flutter and Buffeting Analysis: Finite Element and RPE Solution, J. of Bridge Engineering, ASCE, 4(3), 174-180.

Cai, C. S., Albrecht, P., and Bosch, H. R., (1999b). Flutter and Buffeting Analysis: Luling and Dear Isle Bridges, J. of Bridge Engineering, ASCE, 4(3), 181-188.

Cai, C. S. and Chen, S. R. (2004a). Framework of vehicle-bridge-wind dynamic analysis, J. of Wind Engineering and Industrial Aerodynamics (accepted for publication).

Cai, C. S. and Chen, S. R. (2004b). Wind Hazard Mitigation of Long-span Bridges in Hurricanes, J. of Sound and Vibration (in press).

Cao, Y. H., Xiang, H. F. and Zhou, Y. (2000). Simulation of stochastic wind velocity field on long-span bridges, J. of Engineering Mechanics, ASCE, 1261(1),1-6.

Carlson, J. D., and Spencer, B. F., Jr. (1996). Magneto-rheological fluid dampers for semi-active seismic control, Proc., 3rd Int. Conf. on Motion and Vibration Control, III, 35–40.

Chang, C. C., Gu, M. and Tang, K. H. (2003). "Tuned mass dampers for control of suspension bridges in dual-mode buffeting vibration." J. of Bridge Engineering, ASCE 8(4), 237-240.

Chen, L. K. and Ulsoy, A. G. (2001). Identification of a driver steering model, and model uncertainty, from driving simulator data, J. of Dynamic systems, Measurement, and Control, ASME, 123 (12), 623-629.

194 Chen, S. R. and Cai, C. S. (2001). Modal coupling prediction and application on wind-induced vibration of long-span bridges, Proc. of 5th National workshop on bridge research in progress, Oct. 8-10, 2001, Minneapolis, sponsored by NSF, 189-192.

Chen, S. R. and Cai, C. S. (2002). New control mechanism of Tuned Mass Damper for strong wind-induced coupled vibration of long-span bridges in hurricane prone area, 15th ASCE Engineering Mechanics Division Conference, June 2-5, Columbia University, New York, CD Proceeding.

Chen, S. R. and Cai, C. S. (2003a). Evolution of wind-induced vibration for long-span bridgenumerical simulation and discussion, Computer & Structures, 81(21), 2055-2066.

Chen, S. R., Cai, C. S., Chang, C. C. and Gu, M. (2004). Modal coupling assessment and approximated prediction of coupled multimode wind vibration of long-span bridges, J. of Wind Engineering and Industrial Aerodynamics (in press).

Chen, S. R., Cai, C. S., Gu, M. and Chang, C. C. (2003). Optimal Variables of TMDs for Multimode Buffeting Control of Long-span Bridges, Wind & Structures, 6 (5), 387-402.

Chen, S. R. and Cai, C. S. (2004a). Accident assessment of vehicles on long-span bridges in windy environments, J. of Wind Engineering and Industrial Aerodynamics (submitted for review).

Chen, S. R. and Cai, C. S. (2004b). Strong wind-induced coupled vibration and control with Tuned Mass Damper for long-span bridges, J. of Sound and Vibration (in press).

Chen, X., Matsumoto, M. and Kareem, A. (2000). Aerodynamic coupling effects on flutter and buffeting of bridges, J. of Engineering Mechanics, ASCE, 126(1), 17-26.

Chen, X. Z. and Kareem, A. (2001). On the veering of eigenvalue loci and the physics of coupled flutter of bridges, Proc. 5th Asia-Pacific Conference on Wind Engineering (Kyoto, Japan), 461Chen, X., Kareem, A. and Haan, F. L. (2000). Nonlinear Aerodynamic Analysis of Bridges under Turbulent Winds: the New Frontier in Bridge Aerodynamics, Proceedings of the International Conference on Advances in Structural Dynamics (ASD 2000), Hong Kong, China, December 2000 475-482.

Cheung, Y. K., Au, F. T. K. Zheng, D. Y. and Cheng, Y. S. (1999). Vibration of multi-span nonuniform bridges under moving vehicles and trains by using modified beam vibration functions, J. of Sound and Vibration, 228, 611-628.

Coleman, S. A. and Baker, C. J. (1990). High sided road vehicles in cross winds, J. of Wind Engineering and Industrial Aerodynamics, 36, 1383-1392.

Pages:     | 1 |   ...   | 17 | 18 || 20 |

Similar works:

«2013 South Dakota Crop Protection Guide Corn Weed Control (text) Weeds: Mike Moechnig, Darrell L. Deneke, Leon J. Wrage, Jill Alms, Dave Vos, and Mark Rosenberg Insects: Adrianna Szczepaniec and Buyung Hadi Diseases: Kay Ruden “This document represents only a portion of the 2013 Corn Crop Protection Guide. The complete guide is available at iGrow.org. Information in this publicationis based on SDSU and other research and observations and provides a summary of label recommendations. It is not...»

«A GREAT KOREAN MUSIC PIONEER MIN-CHONG PARK: A PERFORMANCE GUIDE OF HIS SELECTED VIOLIN WORKS A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirement for the degree of Doctor of Musical Arts in The School of Music by Sin Myung Min B.A., Kookmin University, 2006 M.M., Temple University, 2009 December 2014 ACKNOWLEDGEMENTS I would like to express my deep appreciation to the members of my...»

«52 Chimera 26: Geographical Journal, University College Cork Suburbia: social and spatial trends that emerged in Celtic Tiger Ireland. Matthew Williams Department of Geography, University College Cork, Ireland. Long after the roar of the “Celtic Tiger” has become inaudible; its effects remain in the form of ghost estates, incomplete rural development and inadequate service provision across the Irish landscape. This paper will give a brief account of suburban housing development in Ireland...»

«Freshwater prawn (Macrobrachium rosenbergii) farming in Greater Noakhali Districts Catherine Lecouffe January 2005 The Greater Noakhali Aquaculture Extension Project (GNAEP) is a project of the Government of Bangladesh (GoB) supported by Danish International Development Assistance (Danida), under the overall responsibility of the Ministry of Fisheries and Livestock (MoFL) and implemented by the Department of Fisheries (DoF). The project began in July 1998 and has been extended until June 2006....»

«SAFETY DATA SHEET Section 1. Identification Ammonia, Anhydrous Product Name: Synonyms: Ammonia CAS REGISTRY NO: 7664-41-7 Supplier: Tanner Industries, Inc. 735 Davisville Road, Third Floor Southampton, PA 18966 Website: www.tannerind.com Telephone (General): 215-322-1238 Corporate Emergency Telephone Number: 800-643-6226 Emergency Telephone Number: Chemtrec: 800-424-9300 Recommended Use: Various Industrial / Agricultural Section 2. Hazard(s) Identification Hazard: Acute Toxicity, Corrosive,...»

«RI Department of Environmental Management Local Agriculture and Seafood Act Grants Program 2016 GUIDELINES & INSTRUCTIONS The Rhode Island Department of Environmental Management, Division of Agriculture is accepting grant applications for the Local Agriculture and Seafood Act Grants Program. The goal of the program, which was established by the Local Agriculture and Seafood Act (LASA) of 2012, is to support the growth, development, and marketing of local food and seafood in Rhode Island. It is...»

«SOMALIA 2015 HUMAN RIGHTS REPORT EXECUTIVE SUMMARY The Federal Government of Somalia, formed in 2012, was led by President Hassan Sheikh Mohamud. Clan elders nominated the members of the House of the People of the Federal Parliament in 2012. Parliament elected Hassan Sheikh Mohamud as president later that year. Former Transitional Federal Government (TFG) president and presidential candidate Sheikh Sharif described the presidential vote as fair and conceded defeat. The regional governments of...»

«Assessing the Alliance for Green Revolution in Africa August 2009 Report Contributions: Sam Moyo, Walter Chambati, Tendai Murisa and Amade Sucá TABLE OF CONTENTS 1. INTRODUCTION 2. THE CONTEXT: DECLINING AGRICULTURAL PRODUCTIVITY 3. OVERVIEW OF THE AGRA PROJECT 3.1 Background 3.2 Principles and policies: defining the problem and interventions 3.3 Programmes and their implementation 3.4 The actors and partnerships involved 3.4.1 AGRA Leadership 3.4.2 Implementation partnerships 3.4.3 AGRA and...»

«Research in ISSN : P-2409-0603, E-2409-9325 AGRICULTURE, LIVESTOCK and FISHERIES An Open Access Peer Reviewed Journal      Open Access Res. Agric. Livest. Fish. Research Article Vol. 2, No. 1, April 2015: 125-133 FISHERS ACCESS TO THE COMMON PROPERTY WATERBODIES IN THE NORTHERN REGION OF BANGLADESH Md. Amzad Hossain1*, Mousumi Das1, Md. Shahanoor Alam2 and Md. Enamul Haque3 1 Department of Aquaculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur-1706,...»

«As. J. Food Ag-Ind. 2012, 5(02), 96-103 Asian Journal of Food and Agro-Industry ISSN 1906-3040 Available online at www.ajofai.info Research Article Effect of vacuum cooling on physico-chemical properties of organic coriander Apichart Sirinanuwat1, Danai Boonyakiat 2,3 and Pichaya Boonprasom 1,3* 1 Division of Food Engineering, Faculty of Agro-Industry, Chiang Mai University, Thailand, 50200 2 Department of Horticulture, Faculty of Agriculture, Chiang Mai University, Thailand, 50200 3...»

«Tsakiri, Ioannidis, Carty 1 LASER SCANNING ISSUES FOR THE GEOMETRICAL RECORDING OF A COMPLEX STATUE Maria TSAKIRI1, Charalambos IOANNIDIS1, Alistair CARTY2 1 School of Rural and Surveying Engineering, National Technical University of Athens, Greece. 2 Archaeoptics Ltd, Glasgow, UK KEY WORDS: laser scanning, heritage applications, three-dimensional, close range, data capture ABSTRACT Recent advances in laser scanning technology allow for fast and efficient 3D documentation of cultural heritage...»

«ENVIRONMENTAL AND AGRONOMIC EVALUATION OF VALUE-ADDED NITROGEN FORTIFIED POULTRY LITTER AND BIOSOLIDS FERTILIZERS ENVIRONMENTAL AND AGRONOMIC EVALUATION OF VALUE-ADDED NITROGEN FORTIFIED POULTRY LITTER AND BIOSOLIDS FERTILIZERS A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Crop, Soil, and Environmental Sciences By Mark Stephen Reiter Virginia Polytechnic Institute and State University Bachelor of Science in Crop and Soil...»

<<  HOME   |    CONTACTS
2016 www.dissertation.xlibx.info - Dissertations, online materials

Materials of this site are available for review, all rights belong to their respective owners.
If you do not agree with the fact that your material is placed on this site, please, email us, we will within 1-2 business days delete him.