Evolution of US stay cables
After the Second World War, in bridge engineering, one of the most dramatic development is the development of the stay cables. Especially in the last 20 years, perhaps before the stay cables has long been little attention's sake, there are only so many people think of modern dramatic technological developments. By tracing the development of cable-stayed from galvanized steel cable to the current level of technology, the development of a causal relationship is obvious.
Previous stay cables is similar to that used in concrete construction of external tendons, they by the same member, namely cable, anchor, into the hole pipe, corrosion protection materials. Stay Cables of development not only in the type, and almost at the same time in Anchorage and also made the development of anti-corrosion materials.
In the US, policy and guide the Federal Highway Management Committee also have an enormous impact on the development of cable-stayed. Therefore, improved application and acceptance requirements cable-stayed bridge.
This article will discuss the type of cable-stayed, effects and post-tensioned Society of the United States Federal Highway Administration Commission produced, corrosion protection systems as well as stay cable inspection, so that readers stay cables historical development in the United States have a general understanding.
Second, the cable-stayed type
There are many types of cables can be used in cable-stayed bridge in the form of cable and arranged according to their composition, it can be: the mountain by a plurality of wire rope or the mountain of interlocking steel cables, parallel high-strength steel, diameter to 7mm (0.25 inches) parallel prestressed steel wire, steel wire or by the seven mountain of diameter 15mm (0.6 inches) of prestressing strand.
The minimum is allowed to work off the stress intensity and contrast the different types of cables are found in Table 1. Obviously, by comparing the correlation value, use the best cable-stayed structure in parallel prestressed steel ASTM A421 or ASTM A416 prestressing strand.
"Squeeze anchor strand cable" standard forthcoming