THE PROBLEM OF HORIZONTAL CURVES IN HIGHWAYS

A BRIEF STUDY WAS MADE OF THE SIMPLE CIRCULAR CURVE, A TRANSITION CURVE, AND THE CIRCULAR TRANSITION CURVE, OR TRANSITION IN DOUBLE RADIUS. NUMERICAL EXAMPLES WERE USED TO COMPARE THE THREE TYPES OF CURVES TO PROVE THAT THE TRANSITION CURVE IN DUPLICATED RADIUS IS EASIER TO LOCATE IN THE FIELD, AND THAT AFTER THE HIGHWAY IS BUILT, PRESENTS PRACTICALLY THE SAME CONDITIONS AS THE TRANSITION CURVE, IN RELATION TO COMFORT AND SAFETY. AS A RESULT OF THE CURVE STUDY FOR DESIGN AND EXECUTION, THE FIRST PROBLEM ARISING IN CONSTRUCTION, IS THE ONE OF SUPERELEVATION, ESPECIALLY IN THE ADOPTED COEFFICIENT VALUES. WHEN THE CONSTRUCTION CALLED SERRA DE BROTAS WAS UNDER WAY, IN THE SECTION JAU-BROTAS OF THE HIGHWAY JAU-BROTAS-ITIRAPINA, A DESIGN WAS USED FOR A DIFFERENCE IN LEVEL OF ABOUT 200M WITH A SLOPE OF 6% AND MINIMUM RADIUS OF 120M AND, SINCE THREE LANES WERE BEING BUILT FOR DIFFERENT VELOCITIES (40,60 AND 80 KM), THE SEARCH FOR THE TRANSVERSE COEFFICIENT OF FRICTION, BROUGHT VERY HIGH VALUES. ENGINEERS WITHOUT ANY KNOWLEDGE OF THE SUBJECT, IMMEDIATLY GAVE THEIR OPINION TO "CHANGE THE RADIUS", BUT THE DESIGN WAS ALREADY ESTABLISHED AND THE RADIUS 120M WAS THERE. THUS VALUES WERE ESTABLISHED AFTER RESEARCH ON THE SUBJECT; AND IN PARALLEL TO THE FIXING OF THE VALUES, THE IMPRESSION REMAINS THAT THESE VALUES NEED TO BE REFORMULATED IN RELATION TO THE PROGRESS OF VEHICLES AND THE UPDATED VELOCITIES. AS A RESULT OF THE STUDY ON SUPERELEVATION THE SUPERWIDTH WAS STUDIED. AS A RESULT OF THE SECTION CONSTRUCTION, IT BECAME EVIDENT THAT IT WAS NECESSARY TO GIVE A MINIMUM SUPERELEVATION OF 3% TO ANY CURVE, INDEPENDENT OF THE RADIUS. THE PROBABILITY IS SHOWN OF ADOPTING IN EXISTING HIGHWAYS SPECIFIC CONDITION OF COATINGS' RENEWAL-TRANSITION TO THE EXISTING CURVES WITH SUPERELEVATION AND SUPERWIDTH. /RRI/

  • Corporate Authors:

    Sao Paulo Highway Department /Brazil

    ,    
  • Authors:
    • Geraldo, J P
  • Publication Date: 1969

Subject/Index Terms

Filing Info

  • Accession Number: 00203450
  • Record Type: Publication
  • Source Agency: Road Research Institute /Brazil
  • Files: TRIS
  • Created Date: Mar 16 1970 12:00AM