The report describes the use of the TRRL high-speed profilometer to monitor the surface geometry of the Humber bridge. Profile measurements were made at a speed of 15 km/h on the steel deck, prior to machine laying of mastic asphalt, and on the final wearing course before and after trafficking. Surface texture depth measurements were also made on the finished surface. Results show that at short wavelengths the surface is not as even as that of a hand-laid surface but it is more even at longer wavelengths. The riding quality of the surface is not as good as that of a trunk road of bituminous construction because some of the junctions of the box sections in the steel deck caused large irregularities in the final wearing surface. After five months of trafficking, there was little change in the surface profile, texture depth was found to have decreased by an acceptable eight per cent. (A)

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