Our big project at Market place has unexpectedly and unavoidably had to stop. This blog post explains why.
Why has work on Market Place stopped?
The reason is the events of 1966.
The events that took place in 1966 range from the Soviet Union’s Luna 9 landing on the moon months ahead of the US craft Surveyor 1 doing the same; in New York Andy Warhol was “producing” the Velvet Underground and Nico while in Hollywood Brian Wilson pieced together Good Vibrations; China’s Cultural Revolution began while popular opposition to the Vietnam War grew and grew. And West Germany were extra-time runners up in an international football tournament .
Meanwhile in Prescot, Market Place was being re-built for Prescot Urban District Council by a construction firm with the input of an architect and quantity surveyor.
The work included the building of a toilet block, new hard landscaping including a large space concrete flagged space of unknown purpose, and lots of brick or stone walls with stone copings. The space would be linked to the adjacent churchyard by a new flight of stairs, plus a new processional route with stone flagged paving would lead from Market Place into the churchyard via some new iron gates.
Market Place shortly after its 1966 landscaping scheme was completed.
The THI is presently in the process of more or less completely replacing the 1960s landscaping, though if you have passed the site recently you may have notice works have unexpectedly ground to a halt. And it’s all thanks to the people who created the space in 1966.
The works in 1966 included a brand new retaining wall to contain the edge of the churchyard and prevent it from collapsing into the new public open space at Market Place and the new parking area to Greenall Court, itself built in the late 1950s. This wall was strengthened by brick piers located every ten feet along the wall and half of these piers would be strengthened by concrete cores hidden inside the brickwork that gave extra stability.
This is all fine and dandy except that where the wall runs behind the public open space at Market Place, everyone seems to have lost the plot. For a long stretch of the wall there is no additional strengthening and so a long stretch of the wall is leaning slightly after 52 years, and of course it would be extremely wreckless and negligent of us to leave it as it is.
The retaining wall runs from where the churchyard meets the car park in the distance, then behind the former toilet block, around the stairs and then between the level changes between the churchyard and the pubic open space. If you look closely you can see little vertical shadows on the different stretches of wall. these are the shadows of the reinforced piers that help strengthen the wall. No such reinforcements were ever built on the stretch of wall that runs between the stairs and the car park and behind the toilet block.
It turns out the former toilet block was not designed or built to give additional support to the retaining wall behind it: it had a standard wall and roof construction. A seemingly last-minute change to the 1960s design of the public open space meant that the staircase from the churchyard was moved around and as a result one of the concrete-reinforced piers was not built.
Here is a photo taken after the toilet block had been taken down. Not a single bit of additional reinforcement to the big retaining wall was in place – just standard cavity walls – no concrete piers, no buttresses, nothing. Meanwhile the stretch of wall in the background has four support piers.
In all, if the wall over Market Place was strengthened in the same way that it is over the Greenall Court car park, there would be five more piers, of which three would have concrete reinforcement. Our contractor has looked for signs of other reinforcements by checking the foundation of the wall and drilling through it to see if there is hidden concrete reinforcement. No additional strengthening has been found.
Undoing the Problems Created in 1966
This leaves the conundrum for our design team: how do you strengthen an existing retaining wall without disturbing the archaeology of the churchyard on the other side? Also: how to you do this without having bits of structure poking into the rooms of the building that will stand directly next to the retaining wall?
The solution is to provide six new reinforced concrete buttresses to support the wall. Four of these will be hidden within the walls of the new bistro building. One will poke slightly into the kitchen of the bistro and the other buttress is part of the hard landscaping and will be encased in bricks recycled from the site.
In other words, all of this structural strengthening will be virtually undetectable and will have very little impact on the overall design of Market Place.
So why has there been a delay?
Of course with a leaning wall it would be dangerous to continue to build below it and there would be no point putting anything in the ground that would have to be torn out to accommodate the feet of the new buttresses.
After our contractor identified the leaning wall, our structural engineer had to design a solution. To do this further works was needed to help the engineer understand exactly how the wall is constructed – does it get any thicker lower down? Are there any hidden reinforcement? What are its foundations like and how deep are they? Getting this information takes time.
You can’t reinforce a wall until you know how it has been constructed. Here, digging down has revealed the depth and nature of the wall’s foundations (or lack of them!).
Armed with this type of information they can do their calculations and produce a structural design. This design has to be agreed and the architect’s and landscape architect’s designs need to be adjusted, the drainage layout has to be adjusted and the whole lot given to the contractor as a new instruction and of course it takes time for the necessary materials and equipment to arrive on site.
The contractor also has to figure out a method and a sequence for building these new buttresses: care has to be taken so that construction (i.e. digging holes in the ground to put the feet of the new buttresses in) doesn’t make the retaining wall any less stable or a danger to the people working below. This takes time.
The sequence of the works means that the building has to go up first before the landscaping can be fully laid out and constructed. In any case the stone has a long lead–in time between it being ordered and brought to site. This means everything has ground to a halt until the retaining wall is fixed.
When will work start again?
I am pleased to report that work is starting again this week. The first job will be strengthening the wall by building these new buttresses and their foundations. The rest of the work will pick up as planned. The finish date for the work will have been put back a few weeks and once we have a new programme of works I’ll let you know.