A STUDY ON THE CAUSE OF THE CABLE OVERLAY PIPE MELTING DAMAGE BASED ON THE FIELD OBSERVATION OF THE YOKOHAMA BAY BRIDGE

Abstract

  After the Yokohama Bay Bridge was opened to traffic, the girder of National Highway 357 was erected in the lower layer. In the regular inspection conducted just after the lower girder erection, melting damage on the polyethylene overlay pipe was found near the transition appliance which is installed to prevent the cable angular bend in the cable-fixing zone. In order to make clear the cause of the damage, field observation of cable vibration, meteorological data, and temperature change of the polyethylene overlay pipe near the transition appliance was carried out for about 1 year in addition to the detailed inspection of the damaged part. As the results, it was found that the melting damage of the polyethylene overlay pipe was very likely to be caused by the generation of friction heat in the contact part with the transition rubber of the transition appliance. The friction heat was possibly generated by the wind speed restricted type rain-wind induced vibration of cable under the high contact pressure on the upper surface of the cable near the transition appliance which comes from the loading of the lower deck.