Three-day closure of DHB will facilitate additional structural works – General manager

The management of the Demerara Harbour Bridge will be utilising its three-day closure to facilitate critical repairs to the structure, General Manager, Wayne Watson stated Wednesday.

During an engagement at the Umana Yana, Watson noted that these works are in addition to the replacement of Span Nine, which was damaged on the left side of the bridge from east to west, as a result of loaded trucks carrying heavy materials.

To this end, Watson highlighted that currently, the bridge has four broken diamond panels; two are broken in the tension zone at 9R Panel Seven, and two at 9R Panel Nine.

General Manager of the Demerara Harbour Bridge, Wayne Watson

He also noted that some of the remedial works that were done earlier to preserve the structure were also fractured on the Span Nine, Panel Four.

As a result, “It is unsafe to continue to utilise the span in its current state,” he emphasised.

To address this issue, the Ministry of Public Works and engineers of the DHB took into consideration the closure of schools and the tide before ceasing operations for three days.

During the closure river traffic will be restrained for two days.

Watson added that preparation works had commenced the moment the new Span Nine arrived at the mooring station, which saw the installation of deck plates for electrical fittings.

Additional deck plates will be installed shortly.

Meanwhile, on July 24 at 11:59 when the bridge is closed, works will begin with the retraction of Span 10.

The Demerara Harbour Bridge new Span Nine

When fully retracted, all electrical and hydraulic systems including cables, cable wheels, control panels, and the cabin of Span Nine will be removed. The old Span Nine ramp will be disassembled and removed simultaneously.

Water will then be pumped from the Span Nine pontoon to elevate the span above the static rollers, which are the fittings that the bridge slide on.

Day two will see the filling of water into the Span Nine pontoon to lower it on the static roller, once the span is in position to install the ramp.

All tech plates from Span Seven will then be transported to the new Span Nine.

Installation of the cable wheels and control mechanism will then be reinstalled. Docking arms where the two spans meet will also be installed, simultaneously the electromechanical wrenches that move the span in and out will be secured.

Inspection works in the roller guides will commence following all connection and reinstallation works.

Further, inspection and trials will be conducted on day three to ensure the spans align. Thereafter, the spans will be locked and traffic will soon flow.

These works will be conducted in two 12-hour shifts with the DHB and InFab engineers working side by side.

Meanwhile, Watson said daily rehearsals are being conducted to improve methods to achieve the three-day target.