CANTILEVERED END SPAN STEEL PLATE GIRDERS

THE GEOLOGIC CONDITIONS AT A GIVEN STRUCTURE SITE MAY EXERCISE GREAT CONTROL OVER THE STRUCTURAL DESIGN. THIS IS PARTICULARLY TRUE IN UTAH WHICH WAS ONCE INUNDATED BY PREHISTORIC LAKE BONNEVILLE, WHICH DEPOSITED UP TO SEVERAL HUNDRED FEET OF FINE SAND, SILT AND CLAY. STRUCTURE AND ROADWAY FILLS ARE BOTH SUBJECT TO SETTLEMENT. ROADWAY FILLS HAVE BEEN FAIRLY WELL CONTROLLED THROUGH USE OF SAND DRAINS EITHER WITH OR WITHOUT SURCHARGE ON THE FILLS. IT WAS RECOGNIZED IN UTAH THAT IF BRIDGES COULD BE DESIGNED AND CONSTRUCTED INDEPENDENTLY OF THE APPROACH FILLS AND THE ASSOCIATED SETTLEMENT, THE MAINTENANCE PROBLEM WOULD BE REDUCED TO PERIODIC LIFTS OF NEW SURFACING TO MATCH WITH THE BRIDGE DECKS FOR GOOD RIDING QUALITY. THE IDEA WAS DEVELOPED TO UTILIZE STEEL SUPER STRUCTURES WITH CANTILEVERED END SPANS WHICH ELIMINATES DECK JOINTS AND ROADSIDE HAZARDS IN THE FORM OF BRIDGE PIERS ADJACENT TO THE TRAVELED-WAY. THE FIRST STRUCTURE CONSTRUCTED OF THIS TYPE WAS THE WHITE RIVER BRIDGE WHICH ACCOMMODATES A SINGLE LANE OF TRAFFIC AND CROSSES THE RIVER AT 90 DEGREES ON A FLAT GRADE. THE PIERS CONSIST OF A SINGLE LINE OF DRIVEN STEEL PILES ENCASED IN CONCRETE. THE GIRDERS ARE FIXED TO THE TOP OF THE PIERS AGAINST LONGITUDINAL MOVEMENTS BUT ARE FREE TO ROTATE. THE STRUCTURE WAS BUILT WITH A MAXIMUM IMPACT FACTOR OF 30%. BRIDGE STRUCTURES OF THIS TYPE OF DESIGN SINCE THE FIRST STRUCTURE HAVE UTILIZED A 100% LIVE LOAD IMPACT FACTOR IN THE CANTILEVERED SPANS. DETAILS OF DESIGN AND CONSTRUCTION ARE PRESENTED; THIRTEEN STRUCTURES OF THIS TYPE HAVE BEEN COMPLETED. A FOUR SPAN BRIDGE HAS NOT YET BEEN CONSTRUCTED WITH CANTILEVERED AND SPANS. HOWEVER, CALCULATION HAS BEEN MADE OF THE THEORETICAL IDEAL PIER LOCATIONS.

  • Supplemental Notes:
    • pp 190-199, 5 FIG, 3 PHOT
  • Authors:
    • Mansour, A E
  • Publication Date: 1967-10

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  • Accession Number: 00208989
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 7 1994 12:00AM