West Sussex County Council said the River Adur had eroded a support abutting the timber bridge on the western side, resulting in a sinkhole on the approach road last month.
Experienced cyclist Geoff Pike broke his arm while swerving to avoid a pothole, which later widened into the sinkhole, in April: click here to read more.
The bridge was closed from May 23 to allow stabilisation work to be carried out to a riverbank support.
A shuttle bus was provided by the county council because, due to other works in the area, there was no convenient local alternative route across the river.
The bus service will stop today.
A West Sussex Highways spokesman said: “We apologise for the inconvenience caused during these essential works and would like to thank residents for their patience.”
The contractor for the works was Balfour Beatty Living Places.