Download or read book Wind induced Vibrations of Cantilevered Traffic Signal Structures written by Narendra Pulipaka and published by . This book was released on 1995 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Full scale Investigation of Wind induced Vibrations of Mast arm Traffic Signal Structures written by Hung Nguyen Sinh and published by . This book was released on 2014 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Because of their inherent flexibility and low damping ratios, cantilevered mast-arm traffic signal structures are susceptible to wind-induced vibrations. These vibrations cause structural stresses and strains to develop in a cyclical fashion which can lead to reduced service life due to fatigue and, in extreme cases, full collapse. In 2001, after the collapse of several of these structures throughout the United States, American Association of State Highway and Transportation Officials (AASHTO) code standards were updated to include fatigue provisions for traffic signal supporting structures. In New York State, there is particular concern regarding structures spanning longer than 14 meters which currently do not meet these updated fatigue provisions. To address this concern, a full-scale experiment was conducted using an existing 25 meter mast-arm traffic signal structure, located in Malta, NY, in which the response of the structure was observed in relation to in-situ wind conditions. In previous studies, high-amplitude vertical vibrations of mast-arm traffic signal structures have been shown to be due to vortex shedding, a phenomenon in which alternatingly shed, low-pressure vortices induce oscillating forces onto the mast-arm causing a cross-wind response. When the frequency of vortices being shed from the mast-arm corresponds to the natural frequency of the structure, a resonant condition is created. The resonant condition causes the long-lasting, high amplitude vibrations, which may lead to the fatigue failure of these structures. Turbulence in the approach flow is known to affect the cohesiveness of vortex shedding. Results from this full-scale experiment indicate that the surrounding terrain conditions, which affect the turbulence intensity of the wind, greatly influence the likelihood of occurrence of long-lasting, high-amplitude vibrations and also impact whether reduced service life due to fatigue is likely to be a concern.

Download or read book Mitigating Wind Induced Fatigue in Steel Traffic Signal Support Structures written by Kyle Thomas Wieghaus and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Traffic signal structures undergo wind-induced vibrations that result in fatigue damage accumulation and reduced service life. Mast arms have failed and required removal while in service. A dual experimental and analytical modeling approach is taken to mitigate fatigue and fracture in steel traffic supporting structures. A full-scale prototype structure is instrumented to study natural wind response. Excitation mechanisms are identified, and response is characterized statistically by a lognormal distribution. Helical strakes are found to reduce the vortex-induced vibration of cantilevered traffic signal structures, however are not a panacea for fatigue mitigation as marginal service life gains occur in severe wind environments. A probabilistic framework is extended to assess the risk of wind-induced fatigue and estimate service life while considering uncertainties in fatigue demand and capacity. The framework is successfully demonstrated against compiled inspection records. Locations with higher prevailing winds are susceptible to wind-induced fatigue, but the prevalence of low-speed vortex-induced response is primarily responsible for the early fatigue failures in more mild environments. A low-cost damage avoidance system is proposed to mitigate fatigue and fracture in steel traffic supporting structures. Applied prestress introduces a fail-safe, supplementary load path to balance dead load moment, eradicating the detrimental tensile mean stress found in traffic signal structure connections. Field observations are made without and with the proposed system installed. The benefit of applied prestress is quantified by determining service life without and with the system based on changes in response and fatigue resistance using: (i) a code-based technique; and (ii) the proposed probabilistic framework. Fatigue performance is modeled as mean stress-dependent by modifying nominal stress-life relationships. Service life is shown to increase by an order of magnitude, regardless of wind environment. The concept shows potential to reduce the detrimental effects of non-redundancy for a variety of similar, fatigue-critical infrastructure components. The validity of simplified mean stress-dependent connection modeling is explored. A fracture mechanics-based, total life (initiation-propagation) model is used to demonstrate the detrimental effect mean stress has on tube-to-transverse base plate fatigue resistance. Using fatigue strength curves derived from total life analyses, probabilistic analyses are repeated to justify the use of simplified models. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/155395

Download or read book Fatigue resistant Design of Cantilevered Signal Sign and Light Supports written by Mark R. Kaczinski and published by Transportation Research Board. This book was released on 1998 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Deflection Criteria for Wind Induced Deflection Vibrations in Cantilever Highway Sign Structures written by J. A. Edwards and published by . This book was released on 1984 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Field Testing of Cantilevered Traffic Signal Structures Under Truck induced Gust Loads written by and published by . This book was released on 2007 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue resistant Design of Cantilevered Signal Sign and Light Supports written by Robert Joseph Dexter and published by Transportation Research Board. This book was released on 2002 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of Damping in Cantilevered Traffic Signal Structures Under Forced Vibrations written by Patrick S. McManus and published by . This book was released on 2000 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Issues in Structural and Materials Engineering 2011 Edition written by and published by ScholarlyEditions. This book was released on 2012-01-09 with total page 1922 pages. Available in PDF, EPUB and Kindle. Book excerpt: Issues in Structural and Materials Engineering: 2011 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about Structural and Materials Engineering. The editors have built Issues in Structural and Materials Engineering: 2011 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Structural and Materials Engineering in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Issues in Structural and Materials Engineering: 2011 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.

Download or read book Traffic Signal Pole Research damping written by University of Wyoming. Department of Civil and Architectural Engineering and published by . This book was released on 2001 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Researches the weakness and failure potential of cantilevered traffic signal structures due to wind-induced fatigue cracks.

Download or read book Guide Design Specification for Bridge Temporary Works written by American Association of State Highway and Transportation Officials and published by AASHTO. This book was released on 1995 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Loading and Design Methodology for High Mast Lighting Towers written by Robert J. Connor and published by Transportation Research Board. This book was released on 2012 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB’s National Cooperative Highway Research Program (NCHRP) Report 718: Fatigue Loading and Design Methodology for High-Mast Lighting Towers provides criteria for the fatigue design of high-mast lighting towers.

Download or read book Dynamics of Civil Structures Volume 2 written by Shamim Pakzad and published by Springer Nature. This book was released on 2020-09-22 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamics of Civil Structures, Volume 2: Proceedings of the 38th IMAC, A Conference and Exposition on Structural Dynamics, 2020, the second volume of eight from the Conference brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of the Dynamics of Civil Structures, including papers on: Structural Vibration Humans & Structures Innovative Measurement for Structural Applications Smart Structures and Automation Modal Identification of Structural Systems Bridges and Novel Vibration Analysis Sensors and Control

Download or read book Wind Load Effects on Signs Luminaires and Traffic Signal Structures written by and published by . This book was released on 1995 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this study were: (1) to revise the wind load section of the Texas Department of Transportation (TxDOT) standard for highway signs, luminaires and traffic signal structures, and (2) to develop strategies to mitigate large vibrations in single-mast traffic signal structures subject to cross-wind vibrations. The first objective was accomplished by developing a new design wind speed map for the State of Texas. State-of-knowledge wind engineering technology is incorporated in the revised design standard. A better understanding of the cross-wind vibration problem, which takes place in steady winds in the range of 5 to 15 m/s, was obtained by conducting water table, tow tank and field studies.

Download or read book Risk Assessment Model for Wind induced Fatigue Failure of Cantilever Traffic Signal Structures written by C. W. Letchford and published by . This book was released on 2008 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Increased Damping in Cantilevered Traffic Signal Structures written by G. Scott Riggs and published by . This book was released on 1998 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vibration Problems in Structures written by Hugo Bachmann and published by Birkhäuser. This book was released on 2012-12-06 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Authors: Hugo Bachmann, Walter J. Ammann, Florian Deischl, Josef Eisenmann, Ingomar Floegl, Gerhard H. Hirsch, Günter K. Klein, Göran J. Lande, Oskar Mahrenholtz, Hans G. Natke, Hans Nussbaumer, Anthony J. Pretlove, Johann H. Rainer, Ernst-Ulrich Saemann, Lorenz Steinbeisser. Large structures such as factories, gymnasia, concert halls, bridges, towers, masts and chimneys can be detrimentally affected by vibrations. These vibrations can cause either serviceability problems, severely hampering the user's comfort, or safety problems. The aim of this book is to provide structural and civil engineers working in construction and environmental engineering with practical guidelines for counteracting vibration problems. Dynamic actions are considered from the following sources of vibration: - human body motions, - rotating, oscillating and impacting machines, - wind flow, - road traffic, railway traffic and construction work. The main section of the book presents tools that aid in decision-making and in deriving simple solutions to cases of frequently occurring "normal" vibration problems. Complexer problems and more advanced solutions are also considered. In all cases these guidelines should enable the engineer to decide on appropriate solutions expeditiously. The appendices of the book contain fundamentals essential to the main chapters.