THE PROBLEM OF HORIZONTAL CURVES IN HIGHWAYS

TYPES OF CURVES MOST USED IN BRAZILIAN HIGHWAYS WERE STUDIED: THE SIMPLE CIRCULAR CURVE, TRANSITION CURVE, AND THE CIRCULAR TRANSITION CURVE, OR TRANSITION IN DOUBLE RADIUS. THROUGH NUMERICAL EXAMPLES, THE THREE TYPES OF CURVES WERE COMPARED TO PROVE THAT THE TRANSITION CURVE IN DUPLICATED RADIUS WAS MORE EASY TO LOCATE IN THE FIELD, AND THAT AFTER THE HIGHWAY WAS BUILT, PRESENTED 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 UNDERWAY, IN THE SECTION JAU- BROTAS OF THE HIGHWAY JAU-BROTAS-ITIRAPINA, THERE WAS A DESIGN FOR A DIFFERENCE IN LEVEL OF ABOUT 200 M WITH A SLOPE OF 6% AND MINIMUM RADIUS OF 120 M AND, SINCE THREE LANES FOR DIFFERENT VELOCITIES (40, 60 AND 80 KM) WERE GOING TO BE BUILT, THE SEARCH FOR THE TRANSVERSE COEFFICIENT OF FRICTION, BROUGHT VERY HIGH VALUES. VALUES WERE ESTABLISHED AFTER RESEARCHES ON THE SUBJECT. IN PARALLEL TO THE FIXING OF TRANSVERSE VALUES, COEFFICIENT OF FRICTION VALUES, THE IMPRESSION REMAINED THAT THESE VALUES NEEDED TO BE REFORMULATED IN RELATION TO THE PROGESS OF VEHICLES AND UPDATED VELOCITIES. AS A RESULT OF THE STUDY OF SUPER-ELEVATION CAME THE SUPERWIDTH. ALSO, 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. COPIES OF THE CALCULATIONS FOR THE SUPERELEVATION AND SUPERWIDTH, USED IN THE SERRA DE BROTAS, AS WELL AS THE ADOPTED METHODS, WERE INCLUDED. THE PROBABILITY OF ADOPTING TRANSITION TO THE EXISTING CURVES WITH SUPERELEVATIONS AND SUPERWIDTH FOR HIGHWAYS WITH SPECIFIC CONDITION OF COATINGS' RENEWEL, WAS SHOWN. /RRI/

  • Corporate Authors:

    Sao Paulo Highway Department /Brazil

    ,    
  • Authors:
    • Porto, J G
  • Publication Date: 1969

Subject/Index Terms

Filing Info

  • Accession Number: 00203534
  • Record Type: Publication
  • Source Agency: Road Research Institute /Brazil
  • Files: TRIS
  • Created Date: May 16 1977 12:00AM