FULL-SCALE TESTS ON THE MANCUNIAN WAY ELEVATED ROAD

AN INVESTIGATION HAS BEEN MADE INTO THE LONG-TERM STRAINS WHICH HAVE OCCURRED IN PRECASE UNITS FOR THE MANCUNIAN WAY ELEVATED ROAD FROM THE TIME OF CASTING UP TO THE PRESENT. THE INVESTIGATION SHOWED THAT THE LIMESTONE CONCRETE USED FOR THE STRUCTURE HAD A FAVORABLE THERMAL SHRINKAGE CHARACTERISTIC. ON CASTING, ITS LOW COEFFICIENT OF EXPANSION GAVE RISE TO LOWER CONTRACTIONS FOLLOWING THE PEAK HYDRATION TEMPERATURE THAN FOR A CONCRETE OF EQUIVALENT STRENGTH USING A GRAVEL AGGREGATE. IN CONSEQUENCE THERE WAS LESS LIKELIHOOD OF EARLY CRACKING. THE SHRINKAGE OF THE STRUCTURE ARISING FROM MOISTURE LOSS, AS MEASURED IN A PRECAST UNIT WHICH WAS NOT BUILT INTO THE STRUCTURE, WAS NEGLIGIBLE. MEASUREMENTS TAKEN ON PRESTRESSING INDICATED THAT DIFFUSION OF PRESTRESS COULD BE ALLOWED FOR BY TAKING 90% OF THE SECOND MOMENT OF AREA FOR THE FULL CROSS SECTION, WITHOUT MODIFICATION TO THE POSITION OF THE NEUTRAL AXIS. THE LOADING TESTS INDICATED THE ADEQUACY OF THE STRUCTURE: COMPOSITE ACTION OCCURRED BETWEEN THE PRECAST CONCRETE UNITS AND IN SITU CONCRETE IN THE EDGE BEAMS AND CENTRAL RESERVATION, CAUSING THE NEUTRAL AXIS TO BE RAISED ABOVE THAT OF THE PRECAST UNITS ALONE.

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Filing Info

  • Accession Number: 00209076
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jan 12 1970 12:00AM