21st Century bid to repair ancient Walls

Jun 20 2008 by David Holmes, Chester Chronicle

21st Century bid to repair ancient Walls

A £100,000 piece of kit is being used to help engineers devise the best strategy for repairing a collapsed section of the City Walls.

Fortunately, nobody was injured when the 30 metres of wall gave way at the side of The Chester Grosvenor hotel earlier this year.

But the wall is expected to costs hundreds of thousands of pounds to repair and it may not be reinstated until 2010.

This week, specialists were scanning the walls either side of the breach using a £100,000 laser gun which gives readings every 5mm. It will help create a three-dimensional computer-generated image which can be analysed precisely to discover if adjoining areas are suffering from bulges, leans or frailties.

Dan Garner, of the AOC Archaeology Group, said: “I don’t know what the engineers will come up with as a solution. They are waiting for our data. One option is to dismantle the entire stretch of wall and rebuild it but it might be possible to use an alternative engineering solution which involves just repairing the collapsed section.”

The laser survey may shed light on the reasons for the collapse which coincided with the removal of an adjacent brick wall which had concealed the Roman wall.

Fortunately Mike Morris, head of archaeology at Chester City Council, had taken photos of the exposed section before it collapsed which will be helpful when it comes to rebuilding the wall using the fallen stones.

This week it emerged there are problems with another section of the Wall adjacent to the Roman Gardens. Water has been seeping into the sandstone creating concerns about the structure at that point. A gateway between Park Street and the gardens has been reinforced to make it safe. But the reinforcements have lowered the head room by six inches, causing fears someone may bump their head on the way through, resulting in the gate being locked.