DISCUSSION OF CAISSON CONSTRUCTION PROBLEMS AND CORRECTION IN CHICAGO

THE AUTHORS HAVE PRESENTED A VALUABLE AND INTERESTING PROBLEM WHICH IS OFTEN ENCOUNTERED DURING THE CONSTRUCTION OF CAISSONS. MODERN EARTH DRILLING EQUIPMENT HAS REDUCED THE COST OF CAISSON CONSTRUCTION BUT THE PROPER AND STANDARD PROCEDURES FOR CAISSON INSPECTION HAVE NOT YET BEEN DEVELOPED. SOME OF THE INSPECTION PROCEDURES, AS MENTIONED IN THE PAPER, ARE TOO COSTLY FOR SMALL AND MEDIUM SIZE PROJECTS, BUT THEY SEEM TO BE SUITABLE FOR LARGE SIZE PROJECTS AS MENTIONED BY THE AUTHORS. THE AUTHORS HAVE MENTIONED THAT THE BEARING CAPACITY OF SOUND LIMESTONE IN CHICAGO IS ABOUT 100TSF WITH A 20% ALLOWABLE INCREASE IN BEARING PRESSURES FOR EACH FOOT OF PENETRATION INTO THE ROCK. THE WRITERS EXPERIENCE IN THE PHILADELPHIA AREA WITH SOUND MICA SCHIST DOES NOT PROVE TO BE SO. IT WOULD BE APPRECIATED IF THE AUTHORS WOULD REVEAL HOW THE PERCENTAGE INCREASE IN BEARING PRESSURE WAS ARRIVED AT OR HOW THE CHICAGO BUILDING CODE ADOPTED IT. THE USUAL PROCEDURE FOR CAISSON INSPECTION IN THE PHILADELPHIA AREA IS TO DRILL AN EXPLORATORY HOLE OF 2 DIAMETER OF THE SHAFT. IT IS THE EXPERIENCE OF THE WRITER THAT IF THE HOLE IS DRIVEN WITH AN AIR PRESSURE OF 100 PSI, AND IF IT TAKES ABOUT 1 MIN TO DRIVE 1 FT, THE ALLOWABLE BEARING CAPACITY IS ABOUT 30 TSF. EXPERIENCE INDICATES THAT THERE IS A VARIATION FOR DIFFERENT TYPES OF ROCK FORMATION AND SO THERE IS NO STANDARD PROCEDURE FOR CAISSON INSPECTION IN GENERAL. /AUTHOR/

  • Supplemental Notes:
    • Vol 97, No SM8, P 1136
  • Authors:
    • Majumdar, D K
  • Publication Date: 1971-8

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Filing Info

  • Accession Number: 00236234
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Nov 15 1971 12:00AM