The overspend on maintenance for Poole's Twin Sails bridge is more than half a million pounds, a freedom of information (FOI) request has revealed.
Poole Council has spent almost £1.3m keeping it operational since it opened in 2012, having originally set aside about £730,000.
The bridge linking Poole and Hamworthy was closed in August after developing another technical fault.
It is not scheduled to reopen until late autumn.
The FOI request made by the Local Democracy Reporting Service asked for details of all closures and the amount of money spent on maintenance.
It listed 63 days when it was either partly or fully inaccessible, not including the current closure. Ten days were not listed.
In all but one year (2017/18) the council overspent against its maintenance and repairs budget, despite the budget itself rising from £75,000 in 2012/13 to £140,510 last year.
In total £1,273,622 was spent between the date of the bridge's opening and April this year.
An estimated £728,040 had been predicted as being needed.
Andy Hadley, the cabinet member for transport at BCP Council, which succeeded Poole Council, said: "The maintenance expenditure and budget is part of an overall budget for all highway structures and covers planned as well as reactive maintenance.
"The costs of unplanned maintenance for the bridges has been covered from within the overall budget for transportation services over the period.''
He also said most of the closures were to be expected.
"These dates include occasions when it was only closed overnight or remained open to cyclists and pedestrians.
"The majority... were put in place to enable regular maintenance works to be carried out, which is typical for these types of structure.
"Other closures have been for carrying out test lifts following routine replacement of components or to undertake inspections which cannot be done when the bridge is operational."