The Clifton Suspension Bridge in Bristol will be closed during two major summer events.
The bridge is a popular route for walkers to Ashton Court Estate
There are concerns that the 140-year-old landmark could suffer structural stresses due to pedestrians.
The bridge will be closed during this year's 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."
Dayrell McArthur, chairman of the Clifton Suspension Bridge Trust, said the trustees' prime responsibility was the maintenance and conservation of the bridge and to ensure the safety of all who use it.
He said: "We have been in discussion with Bristol City Council, North Somerset Council, crowd control consultants and Avon and Somerset Police and it was agreed that this year the bridge must again be closed to ensure the safety of the public and the bridge."
Bridge closure times will be from 0930 BST on Saturday, 16 July, until 0500 BST on Monday, 18 July.
It will also be closed from 0930 BST on Thursday, 11 August, until 0500 BST on Friday, 12 August, and from midday on Saturday, 13 August, until 0500 BST on Sunday, 14 August.