Bristol's historic Suspension Bridge is to close during two events this summer.
The bridge is a popular route to Ashton Court
Trustees say the 140-year-old landmark could suffer "potentially unacceptable structural stresses due to the volume of pedestrian traffic."
As a result, the bridge will be closed during the Ashton Court Festival and the Bristol Balloon Fiesta.
Bridge Master John Mitchell said: "A crowd of pedestrians on the roadway of the bridge creates a far greater loading than normal car traffic."
He added that more people are walking to increasingly popular events at Ashton Court in recent years.
The bridge will close between:
0700 on 17 July until 0700 BST 19 July
0930 12 August until 0700 13 August
Noon 14 August until 0900 BST 15 August
Dayrell McArthur, chairman of the Clifton Suspension Bridge Trust, said the trustees' responsibility is the "maintenance and conservation of the bridge to ensure the safety of all who use it."
"We have been in discussion with Bristol City Council, North Somerset Council, crowd control consultants and Avon and Somerset police to try to find a way of managing the crowd that would best guarantee the safety of the public and the bridge.
"Unfortunately, all parties reluctantly agreed that the safest option was to close the bridge completely on those occasions when there is the most risk of structural problems."