An analytical study on the residual strength of RC structures with degradation damage

Mohd Noh, Hamidun (2017) An analytical study on the residual strength of RC structures with degradation damage. PhD thesis, Kyushu University.



Nowadays, rebar corrosion has become one of the biggest threats in reinforced concrete (RC) industry due to chemical and mechanical attacks. The main consequences of this phenomenon include a loss of cross section of steel area and the induced of expensive pressure due to volume expansion which caused cracking of concrete, spalling and delaminating of the concrete cover. Thus, it reduces the bond strength between steel reinforcing bar and concrete, and deteriorates the strength of the whole structure. A continuous process of rebar corrosion is not just shorten the service life, reduce the safety and serviceability level, but can also increase the maintenance cost. For the purpose of maintaining safety and serviceability, it is necessary to evaluate the durability of existing structures accurately, in order to predict the structure's rate of deterioration and its future strength. In this study, an experimental work of electrolytic corrosion process was conducted for several levels of rebar corrosion. Next, a static loading test was adopted to assess the structural performance and obtain the residual strength of the beams. Meanwhile, continuum damage mechanics were utilized in analysis of damage caused by chemical and mechanical effects. Within the framework of this method, chemical damage caused by rebar corrosion was considered. Then the effects of chemical and mechanical damage were calculated by introducing two independent scalar damage variables into the constitutive equation. In order to calculate the chemical damage evolution, the diffusion process of chloride ions that impact the rebar corrosion in concrete was stimulated, and an evaluation was conducted of an affected cross-sectional area of a steel bar. The proposed method was found enable to validate the experiment's results and predict the future strength of RC structural members under various exposition periods. In addition, the comparison carried out between the isotropic and orthotropic conditions confirmed the importance of orthotropic analysis in order to obtain the worst-case scenario of the structure. Moreover, the dead load and the hydrostatic stress effects were also investigated and the predominant factor of dead load in the length of a structure span was determined and it was found that the dead load of a structure is dominant in increasing a structure's span length.

Item Type:Thesis (PhD)
Subjects:T Technology > TA Engineering (General). Civil engineering (General) > TA401-492 Materials of engineering and construction. Mechanics of materials
ID Code:10272
Deposited By:Mr. Mohammad Shaifulrip Ithnin
Deposited On:13 Aug 2018 11:27
Last Modified:13 Aug 2018 11:27

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