AN ANALYSIS OF FLEXIBLE STRIPS ON A LINEAR ELASTIC FOUNDATION

SOLUTIONS HAVE BEEN DEVELOPED FOR THE BEHAVIOR OF A FLEXIBLE ELASTIC STRIP SUPPORTED ON A SEMI-INFINITE ELASTIC MEDIUM AND SUBJECTED TO ANY SYSTEM OF FORCES OR MOMENTS. THE SERIES SOLUTION FOR CENTRIC MOMENT, SUGGESTED THAT A FINITE DIFFERENCE SOLUTION IS MORE EFFICACIOUS FOR THE STUDY OF A GENERAL LOADING SYSTEM, AND A COMPUTER PROGRAM WAS DEVELOPED TO ESTABLISH THE CONTACT PRESSURES AND SHEARING FORCE, BENDING MOMENT, ROTATION AND RELATIVE DEFLECTION OF THE STRIP UNDER CONDITIONS OF PLANE STRAIN. LIMITING SOLUTIONS WERE DEVELOPED AND SHOWED THAT THE SOLUTIONS OBTAINED BY THE TWO METHODS OF ANALYSING THE FLEXIBLE STRIP, AGREED QUITE CLOSELY WHEN LIMITING FLEXIBILITIES WERE CONSIDERED. IF THE DISTANCE OF THE LOAD AND MOMENT FROM THE EDGE EXCEEDED A CERTAIN LIMITING VALUE, THE INFINITE PLATE THEORY GAVE THE SHEARING FORCES, BENDING MOMENTS, ROTATIONS AND RELATIVE DEFLECTIONS TO WITHIN 7 PERCENT OF MAXIMUM VALUES. FOR DESIGN PURPOSES THE STRIP CAN BE REGARDED AS EFFECTIVELY RIGID IF THE VALUE FOR RELATIVE RIDGIDITY EXCEEDS 10, AS THE SHEARING FORCES, BENDING MOMENTS, ROTATIONS, AND RELATIVE DEFLECTIONS ARE PREDICTED TO WITHIN 4 PERCENT OF MAXIMUM VALUES. IN STRUCTURE-FOUNDATION INTERACTION STUDIES THE SOLUTIONS ARE SUPERIMPOSED TO ESTABLISH THE FORCES AND MOMENTS IN THE STRUCTURE AND THE FOUNDATION. IN THE PARTICULAR CASE OF A RAFT FOUNDATION, THE MOMENT AND SHEAR DISTRIBUTIONS WITHIN THE RAFT ARE DETERMINED BY SUPERPOSITION OF THE SOLUTIONS FOR A SINGLE FORCE AND MOMENT. EXCEPT IN RARE CASES, THE CONTACT PRESSURES BETWEEN THE RAFT AND THE SUPPORTING SOIL WILL BE COMPRESSIVE, AND SUPERPOSITION OF THE SOLUTIONS WILL BE PERFECTLY VALID. IF THERE IS A RESULTANT TENSILE CONTACT STRESS THIS IS GENERALLY NEGLECTED, AND TO ANALYSE SUCH A NO-TENSION CONDITION IT IS NECESSARY TO USE A TRIAL AND ERROR PROCEDURE, MAKING USE OF THE SOLUTIONS PRESENTED IN THE PAPER. AT THIS STAGE THE DESIGNER MUST USE HIS ENGINEERING JUDGMENT TO DECIDE ON THE VALIDITY OF THE LINEAR-ELASTIC THEORY FOR A SPECIFIC SOIL TYPE. HOWEVER, IT IS LIKELY THAT THE MATHEMATICAL MODEL CHOSEN TO REPRESENT THE STRESS-STRAIN BEHAVIOR OF SOIL IS NOT AS CRITICAL AS COMMONLY THOUGHT WHEN THE INFLUENCE OF THE RIGIDITY OF THE SUPERSTRUCTURE IS TAKEN INTO ACCOUNT IN THE FOUNDATION ANALYSIS.

• Supplemental Notes:
  • Vol Ce Ii, NO 1, PP 1-8, 9 FIG, 2 TAB, 12 REF
• Authors:
  • LEE, I K
  • Phillips, B E
• Publication Date: 1969-4

Media Info

• Serial:
  • Inst Engrs Civil Eng Trans /Australia/

Subject/Index Terms

• TRT Terms: Bending moments; Deflection; Deformation curve; Elasticity (Mechanics); Flexible structures; Foundation soils; Foundations; Linearity; Mat foundations; Pressure; Rotation; Shear stress; Stiffness; Structural analysis; Structural plates; Theory
• Uncontrolled Terms: Contact pressure; Plates; Shear forces
• Old TRIS Terms: Elastic continuum; Flexible foundations; Infinity; Strip
• Subject Areas: Bridges and other structures; Geotechnology; Highways;

Filing Info

• Accession Number: 00209177
• Record Type: Publication
• Files: TRIS
• Created Date: Mar 30 1970 12:00AM