Analytical Study on Dynamic Response of RC Buildings Retrofitted by Compressive CFT Braces
By Hiroyuki Nakahara, Yuichi Nishida, Kenji Sakino and Koichiro Kitajima
Concrete Research and Technology,
Vol.22, No.3, Sep. 2011 (Issue 57)
- Synopsis:
- The criterion of 100mV depolarization is adopted in many cases of cathodic protection (CP) for reinforced concrete under atmospheric conditions. This criterion is very applicable and its validity is confirmed in many cases. However, it is not suitable for members under high moisture conditions such as upper members of piers, which are exposed to splash and tidal zones. Due to poor diffusion of oxygen into the concrete, the potential of steel in the concrete does not shift to a noble value after the CP current is interrupted. In this paper, another criterion, "less noble than -850mV vs. Saturated Copper Sulphate Electrode (CSE)" (-850mV) was examined for specimens in a laboratory. The results show that under the 100mV depolarization criterion, it was difficult to control the current density in order to gain the 100mV depolarization. On the other hand the -850 mV criterion is more applicable under high moisture conditions. It is also found that the pH of the corrosion spots of the rebars decrease to pH4 due to hydrolysis of Fe2+ ions. And corrosion products on the steel are seemed to be reduced by the CP current.
- Keywords:
- existing building out of law, fiber-based analysis, total collapse mechanism, story collapse
