NOLY - Built 1983 Traditional Geocache
eragonSaphira: Cache gone.
-
Difficulty:
-
-
Terrain:
-
Size: 
(micro)
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
This cache was placed as part of the Neighbour of Leap Year's day Bash Event. The container is a nano container, placed ate the site of a bridge over the road, which was built (predictably) in 1983.
Ever wondered how these bridges are built over roads without having too much of an impact on the normal flow of traffic? It is quite a sight to behold!
First and foremost, these bridges are segmental bridges, as they are built in short sections called segments. This is done one piece at a time. Concrete sections, to build the bridge, are either pre-cast and moved to the bridge's final location, or (as happens in most cases) cast-in-place. These bridges are very economical for long spans (over 100 meters), especially when access to the construction site is restricted.
Construction takes place in the following manner:
1. The support towers are built (segmentally). A "slip-form" is used to cast the concrete, and the falsework moves (slips) upward following the sequential concrete "pours". The falsework uses the newly constructed concrete as the basis for moving upward. On our roads, these are typically done between lanes and thus does not have much impact on the flow of traffic.
2. After the towers are built, a superstructure is built at the base of the bridge. This superstructure serves as the "launching" point for building the deck (we'll get back to this in a bit).
3. Now the deck is constructed, beginning at the base ("launching point"), one section at a time. With the cast-in-place bridges, the falsework is connected to the previously installed concrete and used as a mold. Next, the permanent reinforcing steel and supports are installed. Finally, the concrete is placed and cured, freeing the falsework to be moved.
4. Now for the "launching". Hydraulics are now used to pull the completed deck section (this section is made up the cast in place sections) across the "gape", from the base of the bridge, across (resting on) the support towers, to the end of the bridge as sections are casted and cured.
Additional Hints
(No hints available.)