TECHNICAL REPORT STANDARD TITLE PAGE ~1-.~R-e~-'-I~N-o.----~----------~2.~Go-y-er-nm-.-nl~A~c-ce.-.~ ion~N~0.--------~3.~Re-c~ip~i.~nl~',~C~0~lo~lo-g~No-.------------ FHWA/TX-85/ +326-2F ~_~--:----c-.,. __- -_-_--L.-_--_---___- __ ~--..,,--...,..--_. ___ .. _.. .... . -... 4. T,ll. and Sublitl. 5. Report Dol. The Behavi or of Rei nforced Concrete Box Cul verts Under __ ~a!lua ry 1986 "_ Symmetri ca 1 and Unsymmetri ca 1 Live Loads 6. P"rlorming Organi 'nt,on Lod" ~A-u-'h-or-(.- )- --. -----------------. ------- --- 8."-P-er-,or-ml-n~-O-r-g-o-nl-,o-,i-on-R·-"-,o-t·-N·-o- -~ Mark P. Gardner, Jey K. Jeyapalan and Ray W. James Research Report 326-2F 9. Per/orming Orgonizollon Nom .. and Address 10. Work Unil No. Texas Transportation Institute The Texas A&M University System 11. Controcl or C,ronl No. College Station, TX 77843 Study 2-5-82-326 13. Type 0'/ Reporl and Period Covered 12. Sponsoring Agency Name and Addr.ss -----------------~ Texas State Department of Highways and Public Final _ September 1981 Transportation: Transportation Planning Division January 1986 ' ~1-4. -Sp-on-s-or-ni -g' -A·-ge-nc-y..:::..Co-;;;--------l P.O. Box 5051 Austin, Texas 78763 1S . Supplementary Nole. Research performed in cooperation with DOT, FHWA. Research Study Title: Behavior of Reinforced Concrete Box Culverts Under Backfill and Traffic Loads. 16. Ab.tracl The design criteria for reinforced box culverts currently used are primarily empirical in nature, and do not allow for the effects of soil-structure interaction. These effects have beensnown to make a considerable difference in certain situa- tions. In order to have a better understanding of the field behavior of R.C. box culverts, in another research study, the Texas Transportation Institute is studying the behavior of an instrumented 8' x 8' R.C. box culvert ..T he purpose of the study presented herein is to perform prediction analyses of the behavior of this 8' x 8' box c:u Tvert under traffi c loads us i ng a fi ni te element method computer program. In this study, soil properties determined from laboratory tests of soil samples taken at the site were used to determine the stress-strain parameters for use in the computer analyses. The culvert was represented in the analyses by a series of beam elements connected at common nodes. An incremental analysis was used to re- present placement of backfill materials. Predicted earth pressures, stresses and strains at the instrument locations on the test culvert are presented for symmetrical and unsymmetrical live loading conditions at various backfill cover heights. A no-slip soil-culvert interface condition is used throughout the analyses, due to the fact that this more closely represented actual field conditions. Furthermore, predicted bending moment distributions around the culvert are presented for various loading conditions. In addition, the shear force distributions around the culvert are presented in this report. Also, predicted crown deflections are presented for the various loading conditions. 17. Key Words 18. Distribution Statement No restrictions. This document is avail- Reinforced Concrete Box Culverts, able to the public through the National Prediction Analyses of Behavior, Technical Information Service, 5285 Port Traffic Loads. Royal Road, Springfield, Virginia 22161 19. Security Clossi!. (01 this report) 20. Security Clossi!. (01 thi. pagel 21. No. 01 Pages 22. Price Unclassified Unclassified 161 Form DOT F 1700.7 (B-I59) THE BEHAVIOR OF REINFORCED CONCRETE BOX CULVERTS UNDER SYMMETRICAL AND UNSYMMETRICAL LIVE LOADS by Mark P. Gardner Graduate Research Assistant Jey K. Jeyapalan Assistant Research Engineer Ray w. James Assistant Professor Research Report Number 326-2F Research Project 2-5-82-326 Conducted for The Texas State Department of Highways and Public Transportation In cooperation with the U.S. Department of Transportation Federal Highway Administration by the TEXAS TRANSPORTATION INSTITUTE The Texas A&M University System College Station, Texas January 1986 METRIC CONVERSION FACTORS Approximate Conversions to Motric Me.sur. . Approximate Conversions from Metric Me.sur. . Symbol Wh.., You Know Multiply by To Find Symbol Symbol When You Know Multiply by To Find Symbol LENGTH CD - ec~: : oN LENGTH fint finlicth es 3"20. 5 caentiimmeetta.,. cm ~. .C.I.t cmmm cmainlltiimmeattearrs, 0.40 4 Iincdhl. . in y meit pmrildes' 01.96 kmlleotmera, ters kmm -;;;;---- ~;;;: C..D. m ma.t. ..". . 31.13 fylairtd . Iyte t .... km kilometers 0.6 mil .. ml AREA lIIulrl inch. . 6.5 IIIUlr. cantlmet." cm' = - AREA squar. fHt 0.09 squ.ra maters m' cm' Iqua,. cantimater. 0.16 IIIUlri inch" In' IIIUlr. yard, 0.8 squlra mat." m' .. m' Iquar. met.rs 1.2 lIIuara yard, yd' aseqru. .r . mil .. 02.46 IhII.Uctlr"a. .k ilomlters hkmi ' .-., kham ' shqeUcitr"e. k.i llo0m.0et0e0rs m 'l 02.45 .Ieq. u.a. " milts mi' MASS (weight) - MASS (weight) 01 OUncll 28 1I,.rm II .... t lI"m, 0.035 ounc. . 01 Ib pound, 0.45 kilov"m, kll kll kilogr.ms 2.2 pounds Ib short tOM 0.9 tonnes o tonnes 11000 kill 1.1 short lonl 12000 Ibl - VOLUME VOLUME CD w - ml millilit.,. O.Ol fluid ounces fI 01 t TIPb" ; tlalbSlPeOspOoMon , 15 millilitte."rs ml - I lit.l,". 12.10 6 qpuinatrst s qpt fl o~ fluid ounces 30 millilit." ml I lit.,s 0.26 ..l ion, gal c cups 0.24 litl,. I m' cubic mete" 35 cubic flit fI' CpIt qpuinatrlt . 0.4975 lit.e"r , I N - ;=;; ;= - m' cubic miters 1.3 cubic yards yd' ,II ..l ions 3.8 lit.rs I TEMPERATURE (IXICt) ft' cubIC flit 0.03 cubic met." m' yd' cubic y.rds 0.76 cubic mltl" m' C.lsius tiS Ithan Fahrenheit TEMPERATURE (exlCt) t.mperature .dd 321 t.mp.ratur. 'F Flhranheit 5/9 11ft., Calsiu, tamparatura , 3u2b1 trlcti", temper.ture OF 32 98.6 71O2F -401-~!i~ !~!~f ?~!,~!~.+4~~41~~r8 ~~~,i L~I~, 1~~1~ ,+~!,~~~i .~,~r! ~2,~~!O1! ., in· 2.54 I. ...c tlyl. For other allact convlrsions and more detailed tibias. ... NBS -40 -20 0 20 40 60 80 lOa Misc. Publ. 286. Unit' of W.igh,. .nd Measures. Prica $2.25. SO Cat.log No. Cll.l 0:286. ~ n ~ ABSTRACT The design criteria for reinforced box culverts currently used are primarily empirical in nature, and do not allow for the effects of soil-structure interaction. These effects have been shown to make a considerable difference in certain situations. In order to have a better understanding of the field behavior of R.C. box culverts, in another research study, the Texas Transportation Institute is studying the behavior of an instrumented 8' x 8' R.C. box culvert. The purpose of the study presented herein is to perform prediction analyses of the behavior of this 8' x 8' box culvert under traffic loads using a finite element method computer program. In this study, soil properties determined from laboratory tests of soil samples taken at the site were used to determine the stress- strain parameters for use in the computer analyses. The culvert was represented in the analyses by a series of beam elements connected at common nodes. An incremental analysis was used to represent placement of backfill materials. Predicted earth pressures, stresses and strains at the instrument locations on the test culvert are presented for symmetrical and unsymmetrical live loading conditions at various backfill cover heights. A no-slip soil-culvert interface condition is used throughout the analyses, due to the fact that this more closely i; represented actual field conditions. Furthermore, predicted bending moment and shear force distributions around the culvert and crown deflections are presented for various loading conditions. iii IMPLEMENTATION STATEMENT The results of this study show that soil-structure interaction can playa very important role in determining the behavior of certain types of drainage structures under backfill and live loads. This interaction indicates that the design loads specified by present standards may be much simpler than those actually occurring in the field during and after construction of the culvert. By comparing results from finite element method predictions with those from an ongoing study of an instrumented culvert of the same properties and dimensions, good correlation of predicted and measured pressures is found, except for data taken at 2 ft soil cover. While some of the difference may be attributed to measurement errors, it is believed that the finite element model used may in general result in unconservative pressure predictions for concentrated wheel loads and shallow depths of fill. This error is probably due to the increasing importance of the nonlinear soil behavior as soil stresses are increased. It should be noted that the field data presented herein should not be considered for design purposes without further reference to the final results of the field instrumentation study being conducted by the Texas Transportation Institute, Study Number 2-5-81-294, entitled IIDetermi nat i on of Earth Pr essu res on Rei nforced Concrete Box Cu1 verts II. This study is being conducted by Dr. Harry Coyle, Dr. Ray W. James, Richard E. Bartoskewitz, and Dale Brown. Their cooperation and assistance is acknowledged and greatly appreciated. iv DISCLAIMER The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Federal Highway Administration. This report does not constitute a standard, specification or regulation. v