Those planks or bamboo bridges you see in some resorts and some sea settlements in Asia?
These are often called puncheons in the outdoor rec. field.
PUNCHEON Puncheon is an effective way to cross some types of bogs, shallow marshes, and wooded wetlands. It uses sawed, treated lumber or native logs to elevate the trail tread above wet areas that are not feasible to drain. It provides a hardened surface that lasts for many years depending on the material used. The walking surface is parallel to the direction of the trail, and the support structures (sills) rest directly on the ground. The use of puncheon is strongly recommended since a wet, muddy trail and the damage caused from hiking directly through wetlands are undesirable. A puncheon bridge can range from as little as 10 feet to hundreds of feet long for crossing a swamp.
Puncheon can be constructed using either native or milled materials and often is a combination of the two. Most typically, the sill logs are made of long lasting native material (such as cedar, tamarack, locust, etc.) and the walking surface is made of heavy, treated planks. The determination of the material depends on a number of factors—the distance from an access point, ability to haul materials to the site, the availability of native materials, the skills available for the difficult job of hewing native puncheon, the desired length of time between replacement, and the ROS setting
While puncheon properly refers to an elevated walkway where the treadway supports are merely sills or sleepers laid on the ground, the terms puncheon bridge and bog bridge are well understood to mean an actual bridge, usually non-compiant wrt ADA and best practices, but still found in abundance in the backcountry. Pretty much any other terms you find imply proper engineering and standards compliance suitable for developed recreational sites.
Elevated bog bridge on the Appalachian Trail in Carrying Place Township – Maine. Walkway is supported by cedar posts driven to refusal by a people powered pile driver.
These open, narrow footbridges are catwalks.
2 A narrow walkway or open bridge, especially in an industrial installation.
‘Most people find these narrow catwalks to be the most frightening part of the tour.’
I have seen them referred to as
Literally meaning eight bridges in Japanese, they typically have a zig-zag pattern and cross marshy areas often planted with bearded irises. Designers of gardens in the West will often use the term when creating so-called "Zen" gardens.