Parametric Analysis and U.S. Department Safety Concepts of of Transportation Federal Railroad CWR Track Buckling Administration Office of Research and Development Washington, DC 20590 G. Samavedam A. Kish A. Purple J.Schoengart DOT/FRAIORD-93/26 Final Report This document is available to the public DOT-VNTSC-FRA-93-25 December 1993 through the National Technical Information Service, Springfield, VA 22161 ·Jck & Scruccures Notice This document is disseminated under the sponsorship of the Department of Transportation in the interest of information exchange. The United States Government assumes no liability for its contents or use thereof. Notice The United States Government does not endorse products or manufacturers. 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REPORT DATE 3. REPORT TYPE AND DATES COVl~ED December 1993 Final Report February 1990-November 1992 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Parametric Analysis and Safety Concepts of CYR Track Buckling RR419/R4011 6. AUTHOR(S) G. Samavedam*, A. Kish, A. Purple*, and J. Schoengart 7. PERFORMING ORGANIZATION NAMECS) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION U.S. Department of Transportation REPORT NUMBER Research and Special Programs Administration John A. Volpe National Transportation Systems Center DOT-VNTSC-FRA-93-25 Cambridge, MA 02142 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING U.S. Department of Transportation AGENCY REPORT NUMBER Federal Railroad Administration DOT/FRA/ORD-93/26 Off i~e of Research and Development Washington, DC 20590 11. SUPPLEMENTARY NOTES *Foster-Miller, Inc. 350 Second Avenue Waltham, MA 02154-1196 Under Contract to VNTSC 12a. DISTRIBUTION/AVAILABILITY STATEMENT 1Zb. DISTRIBUTION Ca>E This document is available to the public through the National Technical Information Service, Springfield, VA 22161 13. ABSTRACT (Maxi111.111 200 words) The work reported here is part of a major investigation conducted by the Volpe National Transportation Systems Center for the Federal Railroad Achinistration on the thermal buckling of continuous welded rail (CWR) track in the lateral plane with the objective of developing guidelines and recOlllllendations for buckling prevention. This report presents results of the developnent and application of a personal cQlll)Uter (PC) software model for prediction of CWR track buckling strength. This model is based on the dynamic buckling theory previously validated by tests. The model accOl.l'lts for all the f~rtant parameters influencing track buckling viz., rail size, curvature, lateral resistanc:e,tie-ballast friction, fastener torsional resistance, track longitudil'\Bl stiffness, track vertical stiffness, misalignment _..,litude and wavelength, and vehicle parameters. The sensitivity of the buckling temperatures with respect to each of the parameters is quantified, and critical parameters which strongly affect buckling strength are identified. A basis for buckling safety evaluation is presented. An approach using the coqiuter program for the developnent of safety limits in the form of allowable rail temperatures as fl.l'ICtions of track peak lateral resistance, misaligrment ~litude and curvature, is presented. Conclusions of practical interest from the parametric study are presented. 14. SUBJECT TERMS 15. NUMBER OF PAGES 120 Track Buckling, Dynamic Buckling, Lateral Stability, Continuous Welded Rails, Buckling Safety Limits, Parametric Study 16. PRICE ca>E 17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT OF REPORT OF THIS PAGE OF ABSTRACT Unclassified Unclassified Unclassified NSN 7540·01·280·5500 Standard Form 298 (Rev. 2 ·8~> Prescribed by ANSI Std. 239 , 8 298·102 PREFACE This report presents a comprehensive study of continuous welded rail (CWR) track buckling strength as influenced by the range of all key parameters such as the lateral, torsional and longitudinal resistances, vehicle loads, etc. The work was performed under the OMNI Contract DTRS-57-89-D00009 awarded by Volpe National Transportation Systems Center (VNTSC), at Cambridge, MA. The work was done by Foster-Miller, Inc. under the technical direction of VNTSC, and sponsored by the Office of Research and Development, Federal Railroad Administration, U.S. Department of Transportation at Washington, D.C. Mr. William Paxton of FRA is in charge of this research program. The parametric study presented here is based on the computer program jointly developed by VNTSC and Foster-Miller. The computer program is based on the dynamic buckling theory developed and validated by previous research efforts of VNTSC. On the basis of test data, the practical range of each of the parameters involved has been identified and computer runs have been made over this range to yield the buckling strength variations and the sensitivity with respect to the parameters. Critical parameters and their ranges have been evaluated through this process. Several conclusions of practical interest are drawn from this study. lll APPROXIMATE CONVERSIONS TO SI UNITS APPROXIMATE CONVERSIONS FROM SI UNITS Symbol When You Know Multlply By To Find Symbol Symbol When You Know MultlplyBy To Find Symbol LENGTH LENgIH In Inches 25.4 milRmeters mm mm millimeters 0.039 inches In ft feet 0.305 meters m m meters 3.28 feet ft yd yards 0.914 meters m meters 1.09 yards yd ml m miles 1.81 kilometers km km kilometers 0.621 mnes mi AREA AREA In' square inches 645.2 millimeters squared mm2 mm' millimeters squared 0.0016 square inches int ft2 square feet 0.093 meters squared m' m' meters squared 10.764 square feet ft2 yd' square yards mt 0.836 meters squared m' meters squared 1.195 square yards ac ac aaes 0.405 hectares ha ha hectares 2.47 acres mi2 mi' squaremnes 2.59 kilometers squared km2 km' kilometers squared 0.386 square miles VOLUME VOLUME ft oz ftuidounces 29.57 milliliters ml ml milliliters 0.034 fluid ounces fl oz. gal gallons 3.785 liters I I liters 0.264 gallons gal ..... ft' cubic feet 0.028 meters cubed mi m3 meters cubed 35.71 cubic feet ft' < Ill yrJI cubic yards 0.765 meters cubed m3 mi meters cubed 1.307 cubic yards yrJI NOTE: Volumes greater than 1000 I shall be shown In m3• MASS MASS oz ounces 28.35 grams g g grams 0.035 ounces oz lb pounds 0.454 kilograms kg kg kilograms 2.202 pounds lb T shorttons(20001b) 0.907 megagrams Mg Mg megagrams 1.103 short tons (2000 lb) T TEMPERATURE (exact) TEMPERATURE (exact) •F Fahrenheit S(F-32)19 Celeius °C oc Celcius 1.8C +32 Fahrenheit "F temperature or (F-32)11.8 temperature temperature temperature ILLUMINATION ILLUMINATION fc foot-candles 10.76 lux 1, Ix lux 0.0929 foot-candles fc ft foot-Lamberti 3.428 candelalmt cdlm1 cdlm' candela/m2 0.2919 fooHamberts fl FORCE and PRESSURE or STRESS FORCE and PRESSURE or STRESS lbf poundforce 4.45 newtons N N newtons 0.225 poundforce lbf psi poundforce per 8.89 kilo pascals kPa kPa kHopascals 0.145 poundforce per psi square Inch Ill square Inch • SI Is the symbol for the International System of Units (Revised January 1992) < ,,, , •• M·,i~b~\~~ TABLE OF CONTENTS Section Page EXECCTNE SUMMARY---------------------------------------------------------------------- ES-1 J . I~TR OD UCTI ON------------------------------------------------------------------------------------- 1 ' CWR TRACK BUCKLING THEORY AND PARAMETERS ---------------------------------3 2. I Buckling Mechanism-----------------------------------------------------------------------3 ; ! Buckling Response Characteristic--------------------------------------------------------5 2. 3 Buckling Theory---------------------------------------------------------------------------- 6 2. 4 Energy Required for Buckling---------------------------------------------------------- 15 2. 5 Radial Breathing-------------------------------------------------------------------------- 17 3. CWR TRACK BUCK.LING PARAMETERS AND SENSITNITY STUDY--------------- 20 3. I Effects of Rail Properties---------------------------------------------------------------- 21 3. 2 Effects of Curvature---------------------------------------------------------------------- 21 3. 3 Effects of Lateral Resistance ------------------------------------------------------------ 23 3. 4 Effects of Tie/Ballast Friction----------------------------------------------------------- 30 3. 5 Effects of Torsional Resistance--------------------------------------------------------- 32 3. 6 Effects of Longitudinal Resistance----------------------------------------------------- 34 3. 7 Effects of Track Foundation Vertical Stiffness --------------------------------------- 35 3. 8 Effects of Initial Misalignments---------------------------------------------------------