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Structural modification of Bascule bridges for noise mitigation
Title
Structural modification of Bascule bridges for noise mitigation.
Creator
Takkasila, Harinatha Reddy., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Noise mitigation and enhancement of skid resistance on Bascule bridge decks, including bridges, pose a considerable challenge. Typically measured noise levels that vary from 60 to 70 dB(A) need to be reduced to eliminate public concern. The objective of this investigation was to find possible modifications to the structure of the open grid decking to reduce the radiated noise from the bridges and at the same time to improve the skid resistance. This study was complementary to the acoustic...
Show moreNoise mitigation and enhancement of skid resistance on Bascule bridge decks, including bridges, pose a considerable challenge. Typically measured noise levels that vary from 60 to 70 dB(A) need to be reduced to eliminate public concern. The objective of this investigation was to find possible modifications to the structure of the open grid decking to reduce the radiated noise from the bridges and at the same time to improve the skid resistance. This study was complementary to the acoustic testing completed in September 1994 at Florida Atlantic University. Deck panels infilled with different types of lightweight infill material for noise mitigation, were tested for fatigue performance and abrasion characteristics. The computer software ANSYS was used to model the grid panel and analyzed for different depths of concrete infill to evaluate the composite action between the infill concrete and the grid panel. A typical case study on counterbalance dynamics of an infilled deck for the Sunrise Boulevard Bridge, included horsepower requirements, trunnion bearing and bending stresses, and flexural strength adequacies of the stringer and floor beams. Skid resistance values for twelve bridges from E-274 and G-analyst measurements were compared for dry and wet conditions, and accident statistics compiled for the period 1988-1992. The cost analysis of identified options was carried out.
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Date Issued
1996
PURL
http://purl.flvc.org/fcla/dt/15284
Subject Headings
Bridges--Design and construction, Bridges, Iron and steel--Floors--Evaluation, Bridges--Noise, Tires, Traffic noise
Format
Document (PDF)
Noise radiation from an open grid bridge
Title
Noise radiation from an open grid bridge.
Creator
Tournour, Michel Andre., Florida Atlantic University, Cuschieri, Joseph M., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
When a vehicle crosses the grid section of an open grid or bascule bridge, a tonal noise is generated. The tonal character of the noise is a consequence of the periodic excitation of both the tire and the grid, that comes from the interaction between the vehicle tire and the periodic grid members. In this thesis, the parameters that control the level and frequency of the generated noise are investigated, with emphasis on understanding the contribution to the overall noise level from the...
Show moreWhen a vehicle crosses the grid section of an open grid or bascule bridge, a tonal noise is generated. The tonal character of the noise is a consequence of the periodic excitation of both the tire and the grid, that comes from the interaction between the vehicle tire and the periodic grid members. In this thesis, the parameters that control the level and frequency of the generated noise are investigated, with emphasis on understanding the contribution to the overall noise level from the vibrations of the grid. Field and laboratory measurements have been performed, together with analytical analysis, on sample grid designs. By determining the acoustic radiation efficiency of the grid, the noise contribution from the grid vibrations is estimated by combing the radiation efficiency with the field measured vibration levels. The results of this study show that the contribution from the grid is small compared to that which may be coming from the vibration of the tire. Without first reducing tire noise, structural modifications to the grid in the form of damping or acoustic baffles will not produce any significant noise reduction.
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Date Issued
1994
PURL
http://purl.flvc.org/fcla/dt/15046
Subject Headings
Bridges--Design and construction, Bridges, Steel plate deck, Bridges--Noise, Noise control, Bridges--Vibration
Format
Document (PDF)
Theoretical analysis of reinforced and prestressed concrete bridge members strengthened with CFRP laminates
Title
Theoretical analysis of reinforced and prestressed concrete bridge members strengthened with CFRP laminates.
Creator
Qu, Rong., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Nonlinear finite element analyses of the reinforced rectangular beams, prestressed solid slab and prestressed voided slab retrofitted with CFRP laminates are carried out using the software ANSYS(version 5.0) on the Sunwork station. The computer analyses are based on the proposed stress-strain relationship considering the effects of tensile stress on both elastic modulus and maximum compressive stress of concrete. Several assumptions are made in predicting the loss of tensile strength due to...
Show moreNonlinear finite element analyses of the reinforced rectangular beams, prestressed solid slab and prestressed voided slab retrofitted with CFRP laminates are carried out using the software ANSYS(version 5.0) on the Sunwork station. The computer analyses are based on the proposed stress-strain relationship considering the effects of tensile stress on both elastic modulus and maximum compressive stress of concrete. Several assumptions are made in predicting the loss of tensile strength due to crack, confinement due to the laminate bonding, tensile strength due to the prestress force, failure pattern due to the concentrated stress adjacent to the loading point and concrete crushing due to large compressive strain. A subroutine is developed using macro commands of ANSYS. In this research, Branson's equation or Ie procedure is assumed in the prediction of deflection of retrofitted concrete members. The modifications needed due to laminate bonding are the cracking moments of inertia (Icr) of the beams or slabs bonded with CFRP laminates, which are included in the analysis.
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Date Issued
1994
PURL
http://purl.flvc.org/fcla/dt/15083
Subject Headings
ANSYS (Computer system), Reinforced concrete--Plastic properties, Carbon composites, Fiber reinforced plastics, Bridges--Design and construction, Prestressed concrete construction
Format
Document (PDF)