Walls, roofs gave protection, cover to animals, people

Although there are reasons why covered bridges are covered, the shelter they afforded led to unintended uses.
By NORMAN LEIGH
VINDICATOR SALEM BUREAU
SALEM -- Anyone who enjoys the sight of a decades-old covered bridge reaching across a sparkling stream should thank those who designed the structures.
They were meant to last.
The walls and roofs of the spans are intended to protect the bridges' structural elements from the weather. Dampness is the enemy of wooden bridges, which would rot if not sheltered.
Another benefit of covering and walling bridges is that the superstructure shielded horses and livestock from views of deep ravines and rushing waters that could frighten the animals.
The first covered bridge built in America was constructed in 1805 in Philadelphia.
Ensuing decades saw various engineers developing more advanced designs meant to improve bridges' strength, durability and load-bearing capacity.
Named for designers: In time, covered bridges were constructed in styles named after the men who developed specific ways of joining timber beams, wooden pins, iron rods and planking.
Leading designs were the Burr truss, after Theodore Burr; the Town lattice, after Ithiel Town; and the Howe truss, after William Howe.
Covered bridges also gave rise to other uses that were unintended by their designers.
Couples took advantage of their shadows for romance, leading to the spans sometimes being dubbed "kissing bridges."
Advertisers and circus promoters utilized them as billboards. Bandits hid within darkened bridges and waylaid passers-by. Travelers sought shelter beneath their roofs during storms.
People congregated within them for weddings, town meetings, bare-knuckle fights and church suppers.
They were more than simple conveyances. They were part of the fabric of the surrounding community.