What were the reasons for the weight restrictions imposed on the Menai Bridge and for its closure in 2019?
I refer you to my answer to you on WQ86591.
The weight restrictions were imposed in June 2022 and closure was 21 October 2022.
The weight restrictions were imposed in June 2022 after UK Highways A55 Ltd commissioned COWI to determine how to safely refurbish the hangers.
The 7.5t weight limit on the Menai suspension bridge was based on the recommendations from COWI at that time and it being safe to use while the ongoing assessment was undertaken on the complex structural analysis.
A subsequent structural analysis, undertaken in October, demonstrated that in certain loading conditions when the bridge could be subjected to shock loading such as harsh braking, could lead to a catastrophic failure of the suspended bridge deck.
This is turn could lead to a brittle failure of the hangers and through load transfer to adjacent hangers – ultimately an ‘unzipping’ effect on the suspended bridge deck, leading to a catastrophic failure.
It was these findings which led to the Menai suspension bridge closure.