STRESSES IN CONCRETE RUNWAYS OF AIRPORTS

Abstract

THE PROBLEM OF STRESSES IN CONCRETE RUNWAYS OF AIRPORTS IS ESSENTIALLY THE SAME AS THE PROBLEM OF STRESSES IN CONCRETE PAVEMENTS OF HIGHWAYS, EXCEPT THAT BOTH THE WHEEL LOADS THAT MUST BE CONTEMPLATED AND THE AREAS OF CONTRACT BETWEEN TIRE AND CONCRETE ARE GREATER FOR RUNWAYS THAN FOR HIGHWAYS. THESE DIFFERENCES, ESPECIALLY THE GREATER AREAS OF CONTACT, CALL FOR A RE-EXAMINATION OF THE FORMULAS THAT HAVE BEEN DERIVED FOR STRESSES IN CONCRETE PAVEMENTS DUE TO WHEEL LOADS. THE STUDY IS LIMITED TO THE CASE OF LOADS AT AN APPRECIABLE DISTANCE FROM EDGES OR JOINTS. THE REPORT OF RESULTS IS A REPORT OF NO SURPRISES. THE LARGER AREA OF CONTACT BETWEEN THE CONCRETE PAVEMENTS OF THE RUNWAY AND THE TIRE OF EACH WHEEL OF THE LANDING GEAR, AS COMPARED WITH THE CORRESPONDING AREAS FOR TIRES OF TRUCKS ON HIGHWAYS, CALL FOR ONLY VERY SMALL REVISIONS OF THE FORMULAS PRESENTED BY THE WRITER PREVIOUSLY, IN THE PROCEEDINGS OF THE HIGHWAY RESEARCH BOARD, 1926, AND IN PUBLIC ROADS, APRIL 1926 AND DECEMBER 1933. IN FACT, THE NEEDED REVISIONS OF THE FORMULAS ARE SO SMALL COMPARED WITH THE WELL- REALIZED UNCERTAINTIES, INCLUDING THOSE OF THE SUBGRADE, THAT IN MOST CASES THE CORRECTIONS MAY BE IGNORED. YET THE FORMULAS FOR CORRECTIONS ARE SIMPLE AND NOT DIFFICULT TO USE. IN THE INTEREST OF RECORDING THE EVIDENCE THE FAIRLY SIMPLE DERIVATIONS OF THE FORMULAS ARE SHOWN. /AUTHOR/