A £3.9m project is underway on the Humber Bridge to replace four solid steel “A-frames”, which connect the main span bridge deck to the towers at either end of the bridge, to strengthen the landmark crossing.
The works will require the closure of the nearside lane in both directions for up to 40 weeks from the end of October 2013. This is necessary to reduce the load on the structure whilst the work is carried out and to enable safe access to the working areas.
Following on from early traffic disruption when installing traffic management for the Toll Plaza project in July, Bridgemaster Peter Hill is aware that the lane closures are likely to be a cause for concern to customers.
He is keen to explain that the works are essential and will be phased in with current traffic management for the new state-of-the-art electronic toll collection project to ensure that both the duration of disruption to bridge users, and cost of the works, is minimised.
He said: “We appreciate that customers will be worried that this work could affect traffic flow in and around the Humber Bridge toll area, but we want to stress that we are doing all we can to minimise any impact.
“At peak times we will have three approach lanes and three toll booths open in each direction, as at present. We will only reduce this to two lanes, or possibly one, at the quietest times during nights and at weekends, and only when the works make this essential for safety.
“With the maintenance work continuing until next summer, we are also planning ahead for the winter months and the effects poor weather will bring to minimise disruption.”
He also wants to highlight that, although this maintenance work is completely unrelated to the Humber Bridge Toll Project - which is currently underway and will see a smooth, quicker traffic flow across the bridge - it is both economically and operationally sensible to undertake the works in parallel to avoid having to duplicate the lane restrictions for each project separately, which would significantly extend the duration of disruption for bridge users.
The A-frames each weigh five tonnes and are below the 1,410-metre main span of the bridge. They have to be replaced because the A-frame bearings, which allow movement as the bridge contracts and expands with the weather, have become worn over time.
The wear and tear has been exacerbated by the dynamic forces on the giant structure over the 32 years since it was built, including the prevailing westerly wind blowing across the Humber estuary. Expert analysis indicated that complete replacement of the system was necessary and would provide a sustainable, low maintenance solution for the Humber Bridge Board.
The work is being carried out by Hull-based Spencer Group and will, predominantly, be carried out below the carriageway. It will require Spencer, working with sub-contractors, to erect scaffolding to create an expanded working area underneath the bridge deck before the main works can begin.
For updates on the work and traffic flow, visit www.humberbridge.co.uk
Alternatively, look out for news about the lane closures on the Humber Bridge Facebook page, as well as the new Humber Bridge Updates app, which can be downloaded from iTunes and Google Play or from the Play or App Store on your device.
Why is the work being carried out?
The work is to replace four solid steel “A-frames”, which connect the main span bridge deck to the towers at either end of the bridge. They have to be replaced because the bearings supporting these frames, which allow them to move as the bridge contracts and expands with the weather, have become worn over time.
What is being done?
Two “wind shoes” will be fitted, which are designed to absorb lateral loading from the bridge deck, together with vertical “pendals”, which will restrain the bridge deck vertically. Temporary, load-bearing “arms” will be installed to enable the A-frames to be dismantled and removed before the permanent solution is put in place. Concrete strengthening work will also be carried out.
How long will the work take?
The work will be carried out over 40 weeks from the end of October 2013. The Humber Bridge Board is expecting the work to begin on Monday, October 28 2013.
How will I be affected?
The works will require the closure of the nearside lane (the outer lane) in both directions and a speed limit of 30mph across the bridge will be in force. However, the toll booths and approach lanes will remain the same – operating three open in each direction at peak times. These lanes will reduce to two, or perhaps one, at off-peak times, including evenings and weekends.
How much disruption will be caused?
The Humber Bridge Board hopes there will be little disruption to the flow of traffic, but with a single lane and a reduced speed limit, users may need to allow some additional time for crossing the bridge.
Has the construction of the new electronic tag system had an impact? Did the A-frame work have to be carried out at the same time?
No, the replacement of the A-frames is nothing to do with the Humber Bridge Toll Project and the Board are working hard to run both projects in tandem, as smoothly as possible with minimum disruption to commuters.