e-mosty June 2017: Osman Gazi B. US Suspension. Hålogaland B. e-mosty June 2017: Suspension Bridges | Page 56

To achieve an airtight and watertight system, the
termination and sealing of the wrapping at the cable
bands and tower and anchorage saddles required
specific sealing details. The details included a
Cableguard TM neoprene wedge in combination with
caulk sealant.
Once both were placed, a finishing strip of cable
wrapping was installed and then completed with the
installation of two additional stainless steel strap
bands. The finishing strips provide a neat and durable
detail and protect the underlying sealing materials
from the environmental elements (Figure 13).
However, for the Eastbound Bridge, the cable band
gaps were much narrower and ranged from 2mm to
6mm. The gaps were originally filled with a lead seal
that proved difficult to remove due to the hardness of
the sealant and the narrow width of the gap (Figure
15). While removal of the existing lead would allow
the placement of modern sealants, it was believed
that the removal process would have been overly
intrusive and not beneficial to the overall sealing of
the cable band.
Figure 13: Finishing strip at cable band interface
Both bridges had vertically split cable bands with
longitudinal gaps top and bottom. However the width
of the gap, and the manner in which they were
originally sealed, was different.
For the Westbound Bridge the cable band gaps were
approximately 19mm wide. The existing caulk sealant
was removed and replaced with modern sealants,
providing both a weather resistant and airtight seal
(Figure 14).
Figure 15: Eastbound cable band gap filled
with lead sealant
Therefore, air trials were performed on a segment of
the cable that had the new wrapping installed. An
injection sleeve was installed on the cable and a
temporary air blower was utilized to blow air into the
sealed cables and test the in-situ lead sealant in the
cable bands for air leaks.
Using an air pressure at the injection sleeve of 2000Pa,
an air integrity test was performed which revealed
only minor air leaks at the threads of the cable band
bolts and through the suspender ropes; however, the
in-situ lead caulking was air-tight (Figure 16).
Figure 14 ←: Westbound Bridge cable band longitudinal gap with
new caulk sealant
2/2017