Leigh Woods Pier
Back at Clifton for a second long BoM as befits the 100th month and my life long love affair with the bridge.
As last month, this is much too long to post on the web and is available (beyond the introduction below) as a pdf here.
And now it is time to move from simple observation to my real place of work, within the vaults.
Figure 1 By drawing a line across the edge of the shadow and pushing what is below we can see the whole rock face. There are better ways of doing this but I haven’t quite got there yet.
Let’s begin with a picture from last month because it shows the pier quite well. At first sight it looks like a massive block of masonry but Telford would not have done that so why might we think that Brunel would? In 1999 the vaults inside were rediscovered and that is the source of my involvement with the bridge.
Figure 2 The gorge face of the Leigh Woods pier
The scale is completely obscured here by the matching scale of the decorations. Those courses are about 500mm high. The water runs about one third down mark the floor level of the upper layer of vaults. How could anyone imagine that this great block could be solid. Perhaps I should begin with a look at the internal shape as a solid model.
Figure 3 The vaults as if they were solid and the masonry cut away.
A close look at Figure 3 shows some interesting features, but first we need to sort out the orientation. The long central vaults are directly beneath the road, between the tower legs. There are two smaller vaults each side of the block and again this is in two storeys. You can see how the sloping rock surface intersects the vaults. The central space has walls sloping outwards as we move down but that only extends to the floor. The vault below is parallel sided. By contrast, the corner vaults taper inwards all the way down through the two stories. This pattern produces a steadily thickening wall.