TWO-LAYER PLASTIC LINER SYSTEM WILL KEEP AUSTRIAN ALPINE TUNNEL DRY

TWIN LAYERS OF POLYVINYL CHLORIDE (PVC) OUTSIDE THE CONCRETE LINING WILL KEEP DRY 2 PARALLEL BORES ALONG A NEW SECTION OF EXPRESSWAY SOUTH OF SALZBURG. THE TWO-LANE VEHICULAR TUNNELS THROUGH SOUND LIMESTONE FORMATIONS, ARE CONNECTED BY A POST-TENSIONED CONCRETE BOX GIRDER BRIDGE SPANNING THE SALZACH VALLEY. AFTER BORES ARE MUCKED OUT, ROCK ANCHORS ARE PLACED TO HOLD A WIRE MESH MAT AGAINST THE ROCK FACING BEFORE SPRAYING A CONCRETE LAYER WHICH SMOOTHS THE TUNNEL WALLS. A 0.047- IN.-THICK PVC LAYER WILL BE STRETCHED ACROSS THE TUNNEL WALLS AND SECURED TO THE ROCK BY PNEUMATICALLY DRIVEN BOLTS THAT FASTEN PLASTIC COVERED STEEL DISKS. THE DISKS (3.5-IN-DIA), SPACED 3.5 FT APART, PROVIDE A SOLID BASE FOR THE OUTER 0.055-IN THICK PVC LAYER, WHICH IS PROCESSED AGAINST THE BASE LAYER BY A SPECIALLY DESIGNED TRUCK-MOUNTED ROCK. THE TWO LAYERS ARE WELDED BY HIGH FREQUENCY HEATING AT DISK POINTS. THREE STEEL FORM WORK SECTIONS ARE THEN POSITIONED TO CAST THE INNER CONCRETE LINING. THIS METHOD INSURES A COMPLETE WATERTIGHT LINING THAT KEEPS THE 10-IN. THICK INNER CONCRETE SHELL COMPLETELY DRY. THE PVC IS SHRINKPROOF AND CAN STRETCH THREEFOLD WITHOUT RUPTURING. THE CONSTRUCTION OF THE 3.7-MILE EXPRESSWAY SECTION WHICH INCLUDES THE TWO TUNNELS (5,44 9-FT.-LONG NORTHERN TUNNEL AND 7, 929-FT.-LONG SOUTHERN TUNNEL) WILL COST $95 MILLION EXCLUDING THE BRIDGE.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/08919526
• Publication Date: 1973-4-12

Media Info

• Features: Photos;
• Pagination: p. 68
• Serial:
  • Engineering News-Record
  • Volume: 190
  • Issue Number: 15
  • Publisher: McGraw-Hill, Incorporated
  • ISSN: 0891-9526

Subject/Index Terms

• TRT Terms: Boring; Box girders; Bridges; Concrete construction; Costs; Limestone; Pneumatic equipment; Polyvinyl chloride; Sprays (Materials); Tunneling; Wire mesh
• Old TRIS Terms: Pneumatic devices
• Subject Areas: Bridges and other structures; Construction; Finance; Highways;

Filing Info

• Accession Number: 00215625
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 20 1973 12:00AM