Download or read book Fatigue related wind loads on highway support structures written by Gary R. Consolazio and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Related Wind Loads on Highway Support Structures written by Kevin W. Johns and published by . This book was released on 1998 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Performance of Variable Message Sign Luminaire Support Structures Fatigue related wind loads on highway support structures written by Gary R. Consolazio and published by . This book was released on 1998 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes research which focused on determining equivalent static pressures for fatigue loads on cantilevered highway sign support structures. A cantilevered variable message sign (VMS) instrumented with strain gages, pressure transducers, and a wind sentry, was continuously monitored for three months. Short-term testing was conducted on the structure in order to determine the dynamic characteristics such as stiffness, natural frequency, and percent of critical damping. Long-term monitoring was performed to capture the structure's response to natural wind gusts, galloping, and truck-induced wind gusts.

Download or read book Structural Supports for Highway Signs Luminaires and Traffic Signals written by Fouad H. Fouad and published by Transportation Research Board. This book was released on 2003 with total page 59 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 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 Mitigating Fatigue of Cantilevered Overhead Sign Structures Due to Natural and Truck induced Wind Gusts written by Mohamed Salah Gallow and published by . This book was released on 2014 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cantilevered overhead sign structures (COSS) are widely used across highways in the U.S. Several cases of failures have been reported for such structures due to fatigue wind loads. The structure's dynamic characteristics such as natural frequency and critical damping are responsible for its behavior during those loads. When the frequency of wind gusts load matches the fundamental frequency of the OSS, resonance occurs, which causes excessive vibrations. Consequently, fatigue stresses in crease and may exceed the fatigue critical limit, resulting in failure. Vibrations and fatigue stresses amplitudes are dependent on the structure's natural frequency. The objective of this study is investigating natural frequencies of COSS in order to mitigate fatigue stresses due to natural and truck-induced wind gusts. Investigating damping and other fatiguee wind loads are out of the scope in this study. Alterations in factors such as the members' configuration, arrangement, sizes, and layout of the structure control its stiffness and mass distribution which controls its natural frequency and consequently, fatigue stresses. A parametric study was considered in order to investigate the effect of these factors and recommend the best layout between 4-chord, 2-chord, and monotube CSS in mitigating fatigue. Structures were designed according to the American Association of State Highway and Transportation Officials (AASHTO) 2013, Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals (mentioned hereafter as the AASHTO Support Specifications (2013)) and modeled using commercial finite element analysis software. Wind pressure power spectral density and time history loading functions were applied on these structures to simulate natural and truck-induced wind gusts, respectively. Eventally, on the contrary of the 2-chord structure, slanted monotube CSS with curved end post was found to have least mass, highest frequency and nearly smallest fatigue stresses.

Download or read book Fatigue Analysis of Highway Support Structures Under Wind Effects written by Bingbing Shi and published by . This book was released on 1997 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Structural Supports for Highway Signs Luminaires and Traffic Signals written by Fouad Hilmy Fouad and published by . This book was released on 1998 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structural Analysis of Sign Bridge Structures and Luminaire Supports written by and published by . This book was released on 2004 with total page 246 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 Fatigue Performance of Variable Message Sign Luminaire Support Structures written by Gary R. Consolazio and published by . This book was released on 1998 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Calibration of Fatigue Design Wind Pressure for Sign Luminaire and Traffic Signal Support written by Guigui Zu and published by . This book was released on 2013 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study is focused on calibration of fatigue design wind pressure for sign, luminaire and traffic signal support under natural and truck-induced wind gusts. The design of the support structures in Canada is governed by the current Canadian Highway Bridge Design Code (CHBDC). However, the code is not specific on the fatigue design wind pressure (natural or truck-induced) for these structures. Although there are equivalent static natural and truck-induced wind pressures for fatigue design recommended in the provisions of the American Association of State Highway and Transportation Officials (AASHTO), none of relevant studies discussed the implied reliability by using these design pressures based on Canadian practice. Code calibration analyses of the sign, luminaire and traffic signal support under natural and truck-induced wind gusts were carried out in the study. For the calibration, the support structures were approximated by a linear elastic single-degree-of-freedom (SDOF) system, structural response with selected natural frequencies, damping ratios under natural and truck-induced wind gusts was estimated. A target reliability index of 4.25 for a service period of 75 years was adopted for the calibration. The calibration results were used to recommend fatigue design wind pressure for sign, luminaire and traffic signal support under both natural and truck-induced wind gusts. The recommended values could be directly adopted by the CHBDC.

Download or read book Fatigue Risks in the Connections of Sign Support Structures written by Christopher M. Foley and published by . This book was released on 2013 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind Loads on Dynamic Message Cabinets and Behavior of Supporting Trusses written by George Constantinescu and published by . This book was released on 2013 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large Dynamic Message Signs (DMSs) have been increasingly used on freeways, expressways and major arterials to better manage the traffic flow by providing accurate and timely information to drivers. Overhead truss structures are typically employed to support those DMSs allowing them to provide wider display to more lanes. In recent years, there is increasing evidence that the truss structures supporting these large and heavy signs are subjected to much more complex loadings than are typically accounted for in the codified design procedures. Consequently, some of these structures have required frequent inspections, retrofitting, and even premature replacement. Two manufacturing processes are primarily utilized on truss structures - welding and bolting. Recently, cracks at welding toes were reported for the structures employed in some states. Extremely large loads (e.g., due to high winds) could cause brittle fractures, and cyclic vibration (e.g., due to diurnal variation in temperature or due to oscillations in the wind force induced by vortex shedding behind the DMS) may lead to fatigue damage, as these are two major failures for the metallic material. Wind and strain resulting from temperature changes are the main loads that affect the structures during their lifetime. The American Association of State Highway and Transportation Officials (AASHTO) Specification defines the limit loads in dead load, wind load, ice load, and fatigue design for natural wind gust and truck-induced gust. The objectives of this study are to investigate wind and thermal effects in the bridge type overhead DMS truss structures and improve the current design specifications (e.g., for thermal design). In order to accomplish the objective, it is necessary to study structural behavior and detailed strain-stress of the truss structures caused by wind load on the DMS cabinet and thermal load on the truss supporting the DMS cabinet. The study is divided into two parts. The Computational Fluid Dynamics (CFD) component and part of the structural analysis component of the study were conducted at the University of Iowa while the field study and related structural analysis computations were conducted at the Iowa State University. The CFD simulations were used to determine the air-induced forces (wind loads) on the DMS cabinets and the finite element analysis was used to determine the response of the supporting trusses to these pressure forces. The field observation portion consisted of short-term monitoring of several DMS Cabinet/Trusses and long-term monitoring of one DMS Cabinet/Truss. The short-term monitoring was a single (or two) day event in which several message sign panel/trusses were tested. The long-term monitoring field study extended over several months. Analysis of the data focused on trying to identify important behaviors under both ambient and truck induced winds and the effect of daily temperature changes. Results of the CFD investigation, field experiments and structural analysis of the wind induced forces on the DMS cabinets and their effect on the supporting trusses showed that the passage of trucks cannot be responsible for the problems observed to develop at trusses supporting DMS cabinets. Rather the data pointed toward the important effect of the thermal load induced by cyclic (diurnal) variations of the temperature. Thermal influence is not discussed in the specification, either in limit load or fatigue design. Although the frequency of the thermal load is low, results showed that when temperature range is large the restress range would be significant to the structure, especially near welding areas where stress concentrations may occur. Moreover stress amplitude and range are the primary parameters for brittle fracture and fatigue life estimation. Long-term field monitoring of one of the overhead truss structures in Iowa was used as the research baseline to estimate the effects of diurnal temperature changes to fatigue damage. The evaluation of the collected data is an important approach for understanding the structural behavior and for the advancement of future code provisions. Finite element modeling was developed to estimate the strain and stress magnitudes, which were compared with the field monitoring data. Fatigue life of the truss structures was also estimated based on AASHTO specifications and the numerical modeling. The main conclusion of the study is that thermal induced fatigue damage of the truss structures supporting DMS cabinets is likely a significant contributing cause for the cracks observed to develop at such structures. Other probable causes for fatigue damage not investigated in this study are the cyclic oscillations of the total wind load associated with the vortex shedding behind the DMS cabinet at high wind conditions and fabrication tolerances and induced stresses due to fitting of tube to tube connections.

Download or read book Bridge Engineering written by and published by BoD – Books on Demand. This book was released on 2024-07-17 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world’s aging infrastructure faces unprecedented challenges. Bridges, the vital lifelines of the transportation network, are in need of innovative solutions to combat the effects of increased traffic loads, environmental stress, and the passage of time. This edited volume equips you with the knowledge to design and maintain safer, more durable, and sustainable bridges for the future. Explore advancements in the following aspects of bridge engineering: •Material science: Discover strategies to enhance the longevity of concrete bridges, and explore the potential of next-generation materials. •Fatigue assessment: Learn cutting-edge analytical methods to identify and address fatigue damage in critical bridge components, ensuring public safety and efficient maintenance. •Robotic and automation technologies: Uncover how robotics and automation are revolutionizing bridge repair and maintenance, streamlining processes and optimizing resource allocation. •Structural health monitoring (SHM): Delve into the exciting world of the Internet of Things (IoT) and its application in bridge health monitoring. Learn how wireless sensor networks can provide real-time data for proactive maintenance and informed decision-making. This book is a valuable resource for: •Bridge engineers seeking the latest advancements in design, materials, and monitoring techniques. •Policymakers developing sustainable infrastructure strategies. •Researchers pushing the boundaries of bridge engineering through innovative materials and methods. •Students eager to understand the future of bridge design and construction. Embrace the future of bridge engineering. Ensure a safer and more sustainable tomorrow.