A small counterpoint; structures made of a weathering steel, like COR-TEN, don't need to be painted. The trade offs include ensuring the welds weather at the sa

A small counterpoint; structures made of a weathering steel, like COR-TEN, don't need to be painted. The trade offs include ensuring the welds weather at the same rate as the structure and needing a salt alternative for de-icing in the winter. The most prominent example I know of is the New River Gorge Bridge in West Virginia.