A METHOD OF COMPUTING LIVE LOADS TRANSMITTED TO UNDERGROUND CONDUITS

MORE THAN TWENTY YEARS AGO THE IOWA ENGINEERING EXPERIMENT STATION CONDUCTED EXPERIMENTS WHICH INDICATED RATHER DEFINITELY THAT THE LOAD TRANSMITTED TO AN UNDERGROUND CONDUIT BY A TRUCK WHEEL APPLIED AT A ROADWAY SURFACE MAY BE SAFELY COMPUTED BY THE BOUSSINESQ FORMULA FOR A POINT LOAD APPLIED AT THE SURFACE OF A SEMI-INFINITE ELASTIC SOLID. UP UNTIL ABOUT 1929, THE USUAL PROCEDURE FOR COMPUTING LIVE LOADS ON SUCH STRUCTURES WAS TO SUBDIVIDE THE TOP OF THE CONDUIT INTO A NUMBER OF SMALL SUB-AREAS AND CALCULATE THE LOAD ON EACH SUB-AREA BY MEANS OF THIS FORMULA. THE SUMMATION OF LOADS ON ALL THE SUB-AREAS GAVE THE TOTAL LOAD ON THE SECTION OF CONDUIT CAUSED BY A WHEEL LOAD AT THE ROADWAY SURFACE. IN 1929, DR. D. L. HOLL INTEGRATED THE BOUSSINESQ FORMULA TO OBTAIN THE PRESSURE OVER A FINITE RECTANGULAR AREA IN THE UNDERSOIL. THE RESULT OF THIS INTEGRATION WAS A RATHER LENGTHY EXPRESSION WHOSE EVALUATION WAS NOT DIFFICULT, BUT WAS RATHER TEDIOUS. IN 1935 DR. N. M. NEWMARK INTEGRATED THE BOUSSINESQ FORMULA FOR THE PURPOSE OF EVALUATING THE PRESSURE AT A POINT IN THE UNDERSOIL DUE TO A UNIFORMLY DISTRIBUTED LOAD APPLIED OVER A RECTANGULAR AREA AT THE SOIL SURFACE. THIS PROBLEM WAS DIRECTED TOWARD THE DETERMINATION OF PRESSURE AT VARIOUS POINTS IN THE UNDERSOIL FOR THE PURPOSE OF ESTIMATING THE PROBABLE SETTLEMENT OF BUILDINGS AND OTHER STRUCTURES RESTING ON SOIL FOUNDATIONS. IN CONNECTION WITH THIS SOLUTION, NEWMARK PRESENTED A TABLE OF RATIOS WHICH GREATLY SIMPLIFIED THE SOLUTION OF HIS FORMULA. ALTHOUGH HOLL'S PROBLEM AND THAT OF NEWMARK WERE DIRECTED TOWARD DIFFERENT OBJECTIVES, THEY BOTH INVOLVED THE INTEGRATION OF THE BOUSSINESQ FORMULA OVER A RECTANGULAR AREA AND THE SIMILARITY BETWEEN THE TWO SOLUTIONS IS APPARENT. THE AUTHORS HAVE DEMONSTRATED THAT THE NEWMARK TABLE CAN BE USED TO SOLVE HOLL'S EQUATION, AND SUGGEST THAT ITS USE WILL GREATLY SIMPLIFY THE APPLICATION OF THAT EQUATION TO THE DETERMINATION OF LIVE LOADS ON UNDERGROUND CONDUITS. A REPRODUCTION OF NEWMARK'S TABLE IS INCLUDED IN THE PAPER FOR CONVENIENCE, AND SEVERAL EXAMPLES OF ITS APPLICATION IN THE SOLUTION OF HOLL'S EQUATION ARE GIVEN. /AUTHOR/

• Record URL:
  https://onlinepubs.trb.org/Onlinepubs/hrbproceedings/26/26-014.pdf
• Supplemental Notes:
  • Vol 26, pp 179-188, FIGS, 1 TAB. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
• Authors:
  • Spangler, M G
  • Hennessy, R L
  • Barber, E S
• Publication Date: 1947

Media Info

• Media Type: Digital/other
• Monograph Title: Proceedings of the Twenty-Sixth Annual Meeting of the Highway Research Board Held at Washington, D.C. December 5-8, 1946
• Serial:
  • Highway Research Board Proceedings
  • Volume: 26
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Boussinesq equation; Calculation; Conduits; Live loads; Underground structures
• Uncontrolled Terms: Computation
• Old TRIS Terms: Boussinesq formula; Underground
• Subject Areas: Bridges and other structures; Highways; Hydraulics and Hydrology;

Filing Info

• Accession Number: 00204361
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: May 29 1972 12:00AM