A tricky revamp of an important causeway on the Thames has brought the site back into use for emergency services and river users
– making it fit for at least the next 20 years.

Bargehouse Causeway is on the north bank of the Thames, just downriver of Woolwich Ferry. 
It’s thought the causeway was originally built more than 100 years ago for a ferry service, but a few years ago it was noticed that it was being undermined and several deep potholes had opened up in the surface of the causeway. So, on public safety grounds, The Crown Estate, owners of the foreshore, closed the site by installing a gate
at the water’s edge.

With its important role as a river access point, ourselves and The Crown Estate jointly agreed to fund repairs, with the PLA taking the
lead on the £90,000, five-month project. Not an easy job as, throughout the day access to the causeway is subject to the full tidal cycle. The complete causeway is only exposed at low water. All jobs had to be carefully planned as the team could only work on sections
as they were exposed by the tide and for the time they had until the tide came back in.

The causeway was originally built from unbound fill material and
topped off with cobbles and concrete. It was held up by timber piling on either side and was in an

advanced state of deterioration.
In a few places the timber boards
had crumbled, allowing the fill material to be washed away.
The surface collapsed leaving deep potholes in the causeway.

Our civil engineers prepared the
site with 52 new steel piles and hardwood infill panel walling to stabilise the causeway. Then came the trickiest part, laying concrete along the 66-metre length of the causeway, with the tide chasing
the team back every inch of
the way.

Our project engineer Lee Walker,
who has previously managed the construction of numerous Thames piers and site clearance and river
wall piling for the O2 Arena,
oversaw the scheme for the PLA.
He said: “Laying the concrete
surface was a challenge. We had
to be all set to go at low tide. We
had four concrete mixers lined up, specialist pumps and pipe work

running from the river bank to
the foot of the causeway.
As soon as the river was at its lowest level, we called the start
and worked for three hours, pumping 75 tonnes (32 cubic metres) of concrete into place, keeping just ahead of the water throughout.”

“We used special concrete,
so as soon as it was tamped
into place, the surface started

to harden. That was essential
as, within minutes, it was
covered by water.”

The result? A fully refurbished causeway, open again for public and emergency use, and fit for
at least the next 20 years.

The Crown Estate’s Ian Mills, commented: “We’re delighted to have Bargehouse Causeway again safe and available for public use.
“It wasn’t the easiest of jobs, so drawing on the PLA'’s experience
of tidal working was essential.”