Download or read book Fatigue Testing of Stiffened Traffic Signal Structures written by John P. Peiffer and published by ProQuest. This book was released on 2009 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sixteen fatigue tests were performed on twelve cantilevered traffic signal poles to quantify the fatigue resistance of a ring-stiffened built-up box connection. Two poles sizes were tested in three configurations: in-plane, out-of-plane, and diagonal. Cyclic loading was applied to produce stress ranges of up to 16 ksi in the main member, more than six times the stress range observed during field testing. Performance test results for this connection typically plot above an AASHTO detail design stress category D. Connection bolt fatigue failures were observed and may be the limiting fatigue design feature.

Download or read book Fatigue Testing of Ring stiffened Traffic Signal Structures written by Jay Alan Puckett and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Based upon in-service inspection of pole with traditional designs, Wyoming DOT's inventory exhibited approximately a one-third cracking rate. A ring-stiffened connection is presently used. Sixteen fatigue tests were performed on twelve ring-stiffened cantilevered traffic signal pole connections to quantify the fatigue resistance. Two poles sizes were tested in three loading configurations: in-plane, out-of-plane, and diagonal. Cyclic loading was applied to produce stress ranges at several levels and up to 16 ksi in the main member, more than six times the stress range observed during monitoring an in-service pole.

Download or read book Fatigue Testing of Traffic Signal Structures written by Brent Deschamp and published by . This book was released on 2002 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Testing of Traffic Signal Structures Using an Eccentric Mass Oscillator written by Christopher M. Schabron and published by . This book was released on 2011 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Traffic signal and other ancillary structures have failed due to fatigue caused by wind. Such structures are typically lightly damped and have low natural frequencies. The fatigue cracks begin in the base metal near welds. Because of geometric and functional requirements, welds are often category E or lower. Additionally, transportation agencies use unique connection details for a variety of reasons including aesthetics and economy. Fatigue resistance is difficult to categorize because of the uniqueness of the geometries, member sizes, and manufacturing processes. A low-cost performance based procedure is needed in order to test joints as manufactured. Such a procedure would permit the many tests required to develop reliable fatigue performance of a connection. This research focuses on the development of an economical fatigue test procedure for mast arm connections and base plate connections. A full-scale cantilevered traffic signal structure was fitted with an eccentric-mass oscillator, and the oscillator was used to excite the structure near its natural frequency. Different stress ranges were achieved by controlling either the frequency of the motor or the mass-eccentricity of the oscillator in a reliable and repeatable manner. The observations indicate that near-constant amplitude and direction control are possible for in-plane, out-of-plane, and bi-directional load effects. The proposed test is conducted at a fraction of the cost of traditional actuator-controlled methods.

Download or read book Fatigue Risks in the Connections of Sign Support Structures written by and published by . This book was released on 2008 with total page 212 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 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 Analysis of Overhead Sign and Signal Structures written by Jeffrey M. South and published by . This book was released on 1994 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Effects on Traffic Signal Structures written by Brian D. Gray and published by . This book was released on 1999 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue of Large Traffic Signal Structures written by Christopher Hahin and published by . This book was released on 1989 with total page 36 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 Traffic Signal Pole Research written by and published by . This book was released on 2004 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 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 Field Tests and Analytical Studies of the Dynamic Behavior and the Onset of Galloping in Traffic Signal Structures written by Micah Jonathan Florea and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unpredictable fatigue failures of cantilevered mono-tube traffic signal structures in Texas and throughout the United States in recent years have created the need to study their fatigue behavior. Based on recent research, the AASHTO specification has adopted a design equation for galloping loads that is overly conservative in many cases. The Texas Department of Transportation is interested in establishing design criteria for galloping that more accurately represents galloping potential and provides a more efficient design. In this study, three signal structures in Texas were monitored for a total of 9 months to detect the magnitude of galloping forces experienced in the field. Although large amplitude displacements were measured in the field, sustained galloping did not occur. In addition to the field tests, an analytical model was developed and used to perform a parametric study for predicting the galloping potential of traffic signal structures with various properties. The analytical model suggests that modifying the aerodynamic properties of the sign and signal attachments may be the most effective way to eliminate galloping

Download or read book Fatigue Testing and Analysis written by Yung-Li Lee and published by Elsevier. This book was released on 2011-04-18 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue Testing and Analysis: Theory and Practice presents the latest, proven techniques for fatigue data acquisition, data analysis, and test planning and practice. More specifically, it covers the most comprehensive methods to capture the component load, to characterize the scatter of product fatigue resistance and loading, to perform the fatigue damage assessment of a product, and to develop an accelerated life test plan for reliability target demonstration. This book is most useful for test and design engineers in the ground vehicle industry. Fatigue Testing and Analysis introduces the methods to account for variability of loads and statistical fatigue properties that are useful for further probabilistic fatigue analysis. The text incorporates and demonstrates approaches that account for randomness of loading and materials, and covers the applications and demonstrations of both linear and double-linear damage rules. The reader will benefit from summaries of load transducer designs and data acquisition techniques, applications of both linear and non-linear damage rules and methods, and techniques to determine the statistical fatigue properties for the nominal stress-life and the local strain-life methods. - Covers the useful techniques for component load measurement and data acquisition, fatigue properties determination, fatigue analysis, and accelerated life test criteria development, and, most importantly, test plans for reliability demonstrations - Written from a practical point of view, based on the authors' industrial and academic experience in automotive engineering design - Extensive practical examples are used to illustrate the main concepts in all chapters