Bournemouth, Christchurch and Poole Council's apologised after a second technical fault was found on the Hamworthy side of the Twin Sails Bridge in Poole.
It means the structure's having to stay in an upright position until repairs in the mid-autumn, to allow marine traffic to continue to use the channel.
Drivers faced big problems on the road as a result of the problem this morning.
They're being told to use Poole Bridge instead.
The council has given more information on how the fault was discovered:
"Following a noise heard coming from the remaining lifting ram last weekend (Aug 3), engineers attended and on inspection decided there was serious risk of longer term damage to Twin Sails if it was kept in operation.
"To allow marine traffic to continue to use the channel the bridge will need to remain in the upright position until repair around mid autumn.
"Further parts have been ordered."
Julian McLaughlin, Director for Growth & Infrastructure, said:
“The current situation is most unfortunate but with two faults on the same side of the bridge we have no choice but to halt its operation until repaired.
“We have a duty to maintain and protect the structure of the bridge.
“At present our engineers are working hard to replace the first pin so that further examination of the second pin can then progress. Effort is being made with third parties to bring the bridge back into service as soon as possible.
“In the meantime, Poole Bridge is operational and open to all road users.”
Councillor Andy Hadley, portfolio holder for Transport and Infrastructure, said:
“Whilst this will inconvenience and frustrate many people (including myself), I am confident that the engineers are doing everything possible to fix the issue and ensure Twin Sails is not further damaged, and is safe to use.
“We have legal obligations to keep the channel open for boats, especially the RNLI and Sunseeker who need to be able to operate, so we have to close Twin Sails to traffic until new parts can be supplied. Thankfully we still have Poole Bridge available.”
The traffic lights at Blandford Road and Rigler Road in Hamworthy have been changed north to south to help manage traffic flows in the area until Twin Sails is back in service.
The bridge will be left in the upright position to enable marine access through the channel. In the event of strong winds, it will be lowered but remain out of action and re-lifted when conditions improve.