The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Yoshitaka Yoshida - One of the best experts on this subject based on the ideXlab platform.
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wind induced vibration and control of trans tokyo bay crossing Bridge
Journal of Structural Engineering-asce, 2002Co-Authors: Yozo Fujino, Yoshitaka YoshidaAbstract:The Trans-Tokyo Bay Highway Crossing, completed in 1997, is 11 km in total length and is a combined tunnel and multiple Bridge route that includes a ten-span continuous steel box-girder Bridge with a total length of 1,630 m. The two longest spans of this Bridge measure 240 m, and the highway consists of four lanes with an overall width of 22.9 m. In this Bridge, significant vibration due to vortex shedding was observed under prevailing winds almost transverse to the Bridge Axis. This vortex-induced first-mode vibration peaked at a wind velocity around 16-17 m/s, with a maximum amplitude exceeding 50 cm. This paper describes the vortex-induced vibration that occurred in these particular spans, together with the extensive number of wind tunnel tests that were conducted before and after the Bridge construction. It is shown that the results from the field and from the wind tunnel tests are fairly consistent regarding the amplitudes and wind speed range of the vortex-induced vibration in the first vertical vibrational mode of the Bridge. The TMDs developed specifically to control first and second vertical flexural modes of this Bridge and aerodynamic vibration controls employed for higher modes are also explained.
Yozo Fujino - One of the best experts on this subject based on the ideXlab platform.
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Effects of wind barrier on a vehicle passing in the wake of a Bridge tower in cross wind and its response
Journal of Wind Engineering and Industrial Aerodynamics, 2004Co-Authors: S. Charuvisit, Kichiro Kimura, Yozo FujinoAbstract:Abstract Vehicles passing behind a Bridge tower in strong cross winds are affected by sudden change of wind forces acting on them, which may cause accidents due to miss-steering of the drivers. As a countermeasure, wind barrier has sometimes been applied. However, the efficiencies of wind barrier are not known quantitatively, because the characteristics of the aerodynamic forces acting on a vehicle and the response of the vehicle due to those forces are not clear. In this paper, aerodynamic forces acting on a vehicle passing in the wake of a Bridge tower with wind barrier are measured and their characteristics are presented first. Then, using the prediction procedures proposed in a previous study by the authors (J. Wind Eng. Ind. Aerodyn., submitted for publication), a vehicle response simulation was conducted and the effects of the wind barrier on the vehicle response were examined. In the experiment, the change of wind speed is confirmed to become moderate and the magnitude of the aerodynamic forces variation is found to reduce with the installation of wind barrier. Based on simulation results without wind barrier, the vehicle response becomes larger due to increased wind and vehicle speed, and reaches maximum when the wind direction is skewed 30° from the Axis normal to the Bridge Axis and against the vehicle heading direction. The effects of the wind barrier were studied with a fixed steering simulation, and the responses such as side acceleration and yaw angular acceleration are found to be reduced effectively.
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wind induced vibration and control of trans tokyo bay crossing Bridge
Journal of Structural Engineering-asce, 2002Co-Authors: Yozo Fujino, Yoshitaka YoshidaAbstract:The Trans-Tokyo Bay Highway Crossing, completed in 1997, is 11 km in total length and is a combined tunnel and multiple Bridge route that includes a ten-span continuous steel box-girder Bridge with a total length of 1,630 m. The two longest spans of this Bridge measure 240 m, and the highway consists of four lanes with an overall width of 22.9 m. In this Bridge, significant vibration due to vortex shedding was observed under prevailing winds almost transverse to the Bridge Axis. This vortex-induced first-mode vibration peaked at a wind velocity around 16-17 m/s, with a maximum amplitude exceeding 50 cm. This paper describes the vortex-induced vibration that occurred in these particular spans, together with the extensive number of wind tunnel tests that were conducted before and after the Bridge construction. It is shown that the results from the field and from the wind tunnel tests are fairly consistent regarding the amplitudes and wind speed range of the vortex-induced vibration in the first vertical vibrational mode of the Bridge. The TMDs developed specifically to control first and second vertical flexural modes of this Bridge and aerodynamic vibration controls employed for higher modes are also explained.
Martin Schollmayer - One of the best experts on this subject based on the ideXlab platform.
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Through-thickness performance of adhesive joints between FRP Bridge decks and steel girders
Composite Structures, 2009Co-Authors: Thomas Keller, Martin SchollmayerAbstract:The through-thickness performance of adhesive joints between pultruded FRP Bridge decks and steel girders was investigated experimentally and numerically. Through-thickness tensile stresses occur due to uplift forces caused by the load-bearing behavior of the Bridge deck transverse to the Bridge Axis. The tensile stress distribution in the adhesive joint is non-uniform with high stress concentrations below the FRP webs of the cellular deck. The joint ultimate loads could be accurately predicted based on stress concentration factors from FEA and FRP through-thickness tensile strength values obtained from small-scale coupon tests. The total safety factor of the joint was higher than the safety factor of the FRP deck for bending between the main girders. Fatigue loading up to 10 million cycles showed no stiffness degradation.
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Through-thickness performance of adhesive connections between FRP Bridge decks and steel main girders
2009Co-Authors: Martin SchollmayerAbstract:FRP Bridge decks offer several advantages compared with conventional concrete Bridge decks, particularly their much lower weight, but also their resistance against corrosion as well as easier installation and maintenance. The poorly conceived methods available for connecting FRP Bridge decks with their supporting structures – normally steel girders – nonetheless constitute a disadvantage. Connections involving studs or bolts are not appropriate in this case, since FRP is a very brittle material that offers no ductile properties. Bolted connections usually result in much higher stress concentrations, while adhesive bonding is a more material-adapted connection method since larger surfaces can be linked together, thus ensuring reduced stresses. The Bridge system investigated in this thesis consists of a pultruded FRP Bridge deck bonded to steel main girders, the Bridge's main structural components, which have to transmit the dead and traffic loads to the supports, whereas the Bridge deck is spanned in the transverse direction perpendicular to the steel girders. Uplift forces caused by the load-bearing behavior of the Bridge deck transverse to the Bridge Axis lead to through-thickness tensile stresses in the adhesive joint. The main objective of this thesis is the description of the structural behavior in the transverse direction. This includes analysis of the stresses in the adhesive connection as well as determination of the strength of the joints. Analytical and experimental investigations were carried out. It was shown, that the tensile stress distribution in the adhesive joint is non-uniform with high stress concentrations below the FRP deck webs of the cellular deck and above the steel girder web. Alternately inclined deck webs thereby induce significantly higher stresses below the vertical webs. A method for the calculation of the stress state in the adhesive layer is proposed which is validated by numerical and experimental results. The material strength of the connection in terms of a combination of tensile through-thickness and shear stresses is established. The total safety factor of the joint was higher than the safety factor of the FRP deck for bending between the main girders. A possible failure process would not start in the adhesive connection between Bridge deck and steel girder which eventually could lead to additional failure of other structural members. The system is redundant. Fatigue loading up to 10 million cycles showed no stiffness degradation. The results of this thesis prove the existence of a good load-bearing behavior under static and fatigue loads of adhesively-bonded joints between pultruded FRP Bridge decks and structural steel girders, where the adhesive connection is loaded with uplift forces and moments acting in the Bridge deck, in addition to the shear in the connection layer due to composite action. The basis for a design method for adhesively-bonded connections between pultruded FRP Bridge decks and steel girders is provided.
Hideaki Kawaki - One of the best experts on this subject based on the ideXlab platform.
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Influence of Elastomeric Bearings on Traffic-Induced Vibration of Highway Bridges
Transportation Research Record, 2000Co-Authors: Mitsuo Kawatani, Yoshikazu Kobayashi, Hideaki KawakiAbstract:Elastomeric bearings (rubber bearings) have been used in highway pseudo-continuous Bridges without joints changed from simple girders to reduce the environmental influence of traffic-induced vibration. In addition, elastomeric bearings have been adopted in simple girder Bridges for base isolation systems of earthquakeproof structures. Three-dimensional analysis of dynamic response of Bridges under moving vehicles is carried out to examine the change of dynamic response in Bridges caused by replacing steel bearings with elastomeric bearings. Analytical results are compared with experimental results in urban highway Bridges. It is not shown clearly in experiments that natural frequencies are changed slightly in analysis by replacing steel with elastomeric bearings. Although vertical displacements of main girders at the span center do not almost change between steel and elastomeric bearings, horizontal displacement in the Bridge Axis direction becomes larger with elastomeric bearings. For the evaluation of the experimental acceleration of the ground motion, the dynamic reaction force is analyzed and the dynamic influence is investigated.
Dion R. Allicock - One of the best experts on this subject based on the ideXlab platform.
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Seismic Vulnerability of Timber Bridges and Timber Substructures
2007Co-Authors: Ayman A. Shama, John B. Mander, Ian M. Friedland, Dion R. AllicockAbstract:There is little understanding of the seismic behavior of timber Bridges, as historically, little effort has been spent on documenting their performance in past earthquakes or conducting research to develop seismic and/or retrofit requirements for them. This research is devoted towards: (a) documenting the seismic performance of timber Bridges in past earthquakes; (b) assessing, from both theoretical as well as experimental perspectives, the strength and ductility capability of timber piled Bridges in both braced in-plane (transverse to the Bridge Axis) and out-of-plane (longitudinal) directions; and (c) conducting a seismic vulnerability analysis of timber Bridges to assess the expected mode of failure. In pursuit of these objectives, theories are developed to predict the performance of timber piles under lateral loading. Theoretical predictions were verified by experimental studies on full-scale timber specimens, and timber pile-to-concrete cap connections. For braced timber pile bents, a prototype timber Bridge was used to develop a near-full size physical model that was subjected to shaking table experiments and quasi-static reversed cyclic loading tests on the laboratory strong-floor. A nonlinear force-displacement computational modeling study was also conducted as a companion effort to the experimental investigation. Based on the experimental and theoretical research, the seismic vulnerability study of timber Bridges led to the development of fragility curves. It is concluded that timber Bridges are inherently robust and have the ability to withstand major earthquakes with minor to no damage. The main issues is in the provision of adequate deck seating on timber caps.