A small party from IABSE uk visited Clifton Suspension Bridge on 26th April. Our guides were Trish Johnson, the Bridgemaster and John Rees from Cowi, the partner responsible for the engineering maintenance. I have been working with Cowi for some years looking at the masonry which presents its own interest. It was a delight for me and others to look closely at the superstructure.
One detail I found surprising. The chains are accessible at the ground in the side spans and at eye level at mid span. In both places the links are alternately 11and 10 plates side by side. In the side span there are 11at 1” and 10@1-1/8”. At mid span, that reduces to 11@1” and 10@7/8”. Given that the links ar 24ft long and 8” wide using different thicknesses would have given considerable savings but the force in the main chains at the tower is nearly the same as in the side span so how is the change in thickness accomplished. My guess would be in pairs of plates in each link.
If you are fancy in learning more about this amazing structure in excellent detail and superb photos, feel free to visit the 100th bridge of the month, by Bill Harvey.