ELEVATED HIGHWAY ADJUSTS TO BAD GROUND

AN ELEVATED HIGHWAY SECTION IN JOHANNESBURG, SOUTH AFRICA, HAS SPECIAL BEARINGS AND BUILT-IN PROVISIONS FOR JACKING TO CORRECT FOR ANTICIPATED PIER MOVEMENTS BECAUSE THE UNDERLYING SOIL IS UNSTABLE. THE JACKING SYSTEM, DEVELOPED BY GERMANY TO RAISE ELEVATED HIGHWAY STRUCTURES PASSING OVER COAL MINES, WAS USED AND MODIFIED TO BE CAPABLE OF MOVING ELEVATED STRUCTURES HORIZONTALLY. THE JACKING UNIT CONSISTS OF SIX HEAVY-DUTY RAMS, EACH CAPABLE OF LIFTING 330 TONS. AN ELECTRICALLY DRIVEN PUMPING UNIT CAN FEED EACH RAM ON AN INDIVIDUAL CIRCUIT AT THE SAME RATE. THE CONTROL SYSTEM IS DESIGNED TO PROVIDE A UNIFORM RATE OF LIFT, DESPITE UNEQUAL LOADINGS THAT MAY OCCUR DURING THE LIFTING OPERATION. THE PROPORTION OF LOAD CARRIED BY EACH JACK IS MEASURED BY 12 PRESSURE VESSELS DESIGNED FOR 5,000 PSI. SHOULD UNEQUAL LOADING OCCUR, PRESSURE FROM THE VESSELS CAN QUICKLY BE ADJUSTED. THE JACKING SYSTEM CAN ALSO BE ARRANGED TO TILT THE STRUCTURE.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/08919526
• Supplemental Notes:
  • Vol 178, No 17, 1 FIG, 5 PHOT
• Publication Date: 1967-4-27

Media Info

• Serial:
  • Engineering News-Record
  • Publisher: McGraw-Hill, Incorporated
  • ISSN: 0891-9526

Subject/Index Terms

• TRT Terms: Aerodynamic lift; Control; Control systems; Highway bridges; Jacks (Mechanical equipment); Loads; Motion; Road construction; Unstable soil
• Uncontrolled Terms: Jacking; Lifts
• Old TRIS Terms: Horizontal variation; Load control; Vertical movement
• Subject Areas: Construction; Geotechnology; Highways;

Filing Info

• Accession Number: 00214721
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 4 1994 12:00AM