The Analysis Of Tribology Damage Mechanism Of The Stayed Cable From Tongzilin Bridge In Yalongjiang

With the development of the technology in construction in recent years, more and more cable stayed bridge which always be treated as the beautiful and useful style, was built in the exercise of long span bridge. Stayed cable is the primary bearing carrier for main beam, but its service life is found too short. This limitation affected the natural life of the whole bridge seriously.The stayed cable of the Tongzilin Cable Stayed Bridge in Panzhihua, has served 20 years when it is reinforced, with its polyethylene protecting jacket protected well. However, serious damage is found when the stayed cable has been anatomized. Observed comparatively and using scanning electron microscopy-X-ray energy dispersive spectroscopy (SEM-EDX), laser scanning confocal microscope (LSCM) and other equipments to scan those serious damaged wire, carefully analyzing the damage of the surface, we can get the conclusion:1. In structure of the internal cable, the free elongation part (the middle of the cable) has some damage, but it's perfect in metal colour, without any rust. The part near main tower (the head of the cable) has a little rust and damage. No grout was found in both the front parts. However, it is more serious about the damage and rust in the cable near main beam (the tail of the cable), and much grout accumulates there; The fretting damage and corrosion both affects the safe of the cable's use. To view the situation as a whole, steel wire damages in the cable has an obviously symmetrical trend, and the whole cable can reduce the use of the moving loads in the free elongation part.2. In the wire of the stayed cable, new plane is created where the damage is too serious; the axial stress is obvious in the damage on macroscopic level. But, we found there is combined effect of axial, tangential and radial friction mechanism on microcosmic level. In the free elongation part, the tangential and radial damage is very obvious, the depth is 6-8 um, which is much deeper than the two terminals. However, the steel wires'wear is more obvious in the head and the tail, and the fatigue always be concealed. New plane was created coninuely in the tail, with a lot of rust adsorbed. So the tail of the cable is the crucial part for stayed cable's natural life..3. The component of the surface is detected in detail in the zone where the damaged is serious by X-ray energy dispersive spectroscopy (EDX). The content of oxygen and zinc decreases, and iron increases; it shows that the galvanization layer is damaged seriously; the element is bare in the air and the friction carries on. The other zones galvanization layer is steady as Zn0.4. Faced with the difficulty of the check in crack expanding, the cable was cut. The section was polished, and scanned by optical microscope. No obvious crack was found, but it's rough on the edge of the section where the external damage is serious.