A47 GREAT YARMOUTH WESTERN BYPASS: PERFORMANCE DURING THE FIRST THREE YEARS

The A47 Great Yarmouth wester bypass was constructed between September 1982 and March 1986. The design brief was to provide a road across very soft alluvial deposits with a low maintenance requirement without a significantly high capital expenditure. The design that evolved comprised installation of band drains, construction of a reinforced granular mattress, staged constuction with settlement periods, surcharging and finally a continually reinforced concrete road base. Special features comprised two unpiled underpasses designed integrally with the roadbase, to settle at the same rate as the road and the placement of polystyrene fill to reduce diffential settlement and lateral loading onto the piles af an adjacent bridge over the Great Yarmouth to Norwich railway. This interim report presents the results of the first three years of monitoring the rate of settlement, as part of a five year project.