Log bridge
Encyclopedia
A log bridge is a bridge
that uses logs that fall naturally or are intentionally felled or placed across streams. The first manmade bridges with significant span were probably intentionally felled trees. The use of emplaced logs is now sometimes used in temporary bridges used for logging roads, where a forest tract is to be harvested and the road then abandoned. Such log bridges have a severely limited lifetime due to soil contact and subsequent rot and wood-eating
insect
infestation. Longer lasting log bridges may be constructed by using treated logs and/or by providing well drained footings of stone
or concrete
combined with regular maintenance to prevent soil infiltration. This care in construction can be seen in the bridge illustrated, which has well locked dry set stone abutments and a footpath leveled with boards.
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...
that uses logs that fall naturally or are intentionally felled or placed across streams. The first manmade bridges with significant span were probably intentionally felled trees. The use of emplaced logs is now sometimes used in temporary bridges used for logging roads, where a forest tract is to be harvested and the road then abandoned. Such log bridges have a severely limited lifetime due to soil contact and subsequent rot and wood-eating
Xylophagy
Xylophagy is a term used in ecology to describe the habits of an herbivorous animal whose diet consists primarily of wood. The word derives from Greek ξυλοφάγος "eating wood", from ξύλον "wood" and φαγεῖν "to eat", an ancient Greek name for a kind of a worm-eating bird...
insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
infestation. Longer lasting log bridges may be constructed by using treated logs and/or by providing well drained footings of stone
Rock (geology)
In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...
or concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
combined with regular maintenance to prevent soil infiltration. This care in construction can be seen in the bridge illustrated, which has well locked dry set stone abutments and a footpath leveled with boards.