• Structural Engineering and Mechanics
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• v.54 no.6
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• pp.1111-1133
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• 2015

Rebar corrosion in concrete is one of the main causes of reduction of service life of reinforced concrete buildings. This paper presents the influence of rebar corrosion on the structural behavior of reinforced concrete (RC) buildings subjected to strong earthquake ground motion. Different levels of rebar corrosion scenarios were applied on a typical four story RC frame. The deteriorated conditions as a result of these scenarios include loss in cross-sectional area and loss of mechanical properties of the reinforcement bars, loss in bond strength, and loss in concrete strength and its modulus of elasticity. Dynamic analyses of the frame with different corrosion scenarios are performed with selected strong earthquake ground motion records. The influences of degradation in both concrete and reinforcement on structural behavior are investigated by comparing the various parameters of the frame under different corrosion scenarios with respect to each other. The results show that the progressive deterioration of the frame due to rebar corrosion causes serious structural behavior changes such as change in failure mode. The intensity, propagation time, and extensity of rebar corrosion have very important effects on the level of degradation of steel and concrete, as well as on the earthquake behavior of the structure.

• Earthquakes and Structures
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• v.5 no.3
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• pp.321-341
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• 2013

This paper investigates earthquake response of reinforced concrete regular frames subjected to rebar corrosion. A typical four-story reinforced concrete frame is designed according to Turkish Earthquake Code in order to examine earthquake response. Then different levels of rebar corrosion scenarios are applied to this frame structure. The deteriorated conditions as a result of these scenarios are included loss in cross sectional area of rebar, loss of mechanical properties of rebar, loss in bond strength and variations in damage limits of concrete sections. The frame is evaluated using a nonlinear static analysis in its sound as well as deteriorated conditions. The rebar corrosion effect on the structural response is investigated by comparing the response of the frame in each scenario with respect to the sound condition of the frame. The results shows that the progressive deterioration of the frame over time cause serious reductions on the base shear and top displacement capacity and also structural ductility of the corroded frames. The propagation time, intensity, and extensity of rebar corrosion on the frame are important parameters governing the effect of rebar corrosion on earthquake response of the frame.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.11a
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• pp.133-138
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• 2002

Rebar work takes up big proportion in a construction work. The current process of purchasing, cutting and election, and working of rebar induces a lot of loss in rebar. This study is focused on analyzing the problem and the present condition of the process from the calculating of rebar quantifies to the actual constructional stage through surveying those who have experience in the estimation department, or the construction site of a domestic construction company. Many reform measures such as diversification of standard(i.e., 8-meter)bar, calculation of rebar quantities and construction according to the rebar election drawing, expansion of accuracy in layout plan, thoroughness in examination of layout plan in advance, utilization of the worked material, systemization of rebar control(management), and a shift in attitude of the field(site) manager were proposed as the result of the survey.

• Advances in concrete construction
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• v.8 no.4
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• pp.247-255
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• 2019

Several reinforced concrete structures that get deteriorated by rebar corrosion are retrofitted using Carbon Fiber Reinforced Polymer (CFRP). When rebar comes in direct contact with CFRP, rebar may corrode, as iron is more active than carbon. Progression of corrosion of rebar in strengthened RC structures has been carried out when rebar comes in direct contact with CFRP. The experimentation is carried out in two phases. In phase I, corrosion of bare steel bar is monitored by making its contact with CFRP. In phase II, concrete specimens with surface bonded CFRP were casted and subjected to the realistic exposure conditions keeping direct contact between rebar and CFRP. Progression of corrosion has been monitored by various parameters: Half-cell potential, Tafel extrapolation and Linear Polarisation Resistance. On termination of exposure, to find residual bond stress between rebar and concrete, pull-out test was performed. Rebar in contact with CFRP has shown substantially higher corrosion. The level of corrosion will be more with more area of contact.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.109-110
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• 2015

Estimation of rebar quantity may be used as an index to evaluate the economic feasibility of structural designs. However, when using the software to estimate the rebar quantity, there may be some limitations such as data loss caused by human errors and estimation delays caused by increased input time, since the information on arrangement of rebar is inserted manually. To solve the problems of such quantity estimation software, it is necessary to develop a method on automatic input/output of structural design information for quantity estimation and an algorithm for accurate estimation of rebar quantity. The purpose of this study is to improve the existing rebar quantity estimation by connecting with the database on information related to rebar estimation and the algorithm for rebar estimation, in order to develop an algorithm to estimate an accurate, net rebar quantity. The study result can be used as basic data for development of software for efficient structural designs and automatic framework estimation of buildings.

• Korean Journal of Construction Engineering and Management
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• v.13 no.1
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• pp.106-117
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• 2012

The proportion of rebar factory manufacturing which has been settled down in Korea recently seems to increase because of their strength such as high decreasing rate of rebar loss and manufacturing accuracy and the external factors such as an increase of downtown projects and a decrease of skilled workers. However, factory manufacturing using straight rebars causes a certain amount of rebar loss and an environmental problem including $CO_2$ emissions. To solve these problems, Bar in coil (BIC) has been introduced; however its application is very rare because it has not been produced so far in Korea and manufacturing machines of BIC are very expensive. Also, although BIC's application is expected to expand due to its strengths, few analysis of its application has been conducted. Therefore in this study, analysis of the BIC's characteristics and the influence to the rebar manufacturing industry are conducted for the advancement of rebar work as a basic research. To achieve this, inquiry on the present condition of rebar manufacturing industry in Korea is implemented. Then, the validation of BIC's applications by aspects of industry and the analysis of stakeholders' economical profit and loss are conducted.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.4
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• pp.289-296
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• 2014

The rebar detailing is an important work influencing the final performance and quality of RC structures. But it is one of the most irrational and illogical activity in construction site. Many groups of workers, including main contractors, structural engineers, shop drawers, rebar fabricators, and etc., participate in this activity. A loosely-organized process for this activity is apt to produce a big amount of rebar loss or even degraded structures. A 3-dimensional rebar auto-placing system, called as Rebar Hub, has been designed and implemented in this research. Rebar Hub provides a totally integrated service from 3D structural modeling of buildings to rebar auto-placing considering anchorage, splice, and the length of ordered rebar. In addition, Rebar Hub can recognize the 2D drawing CAD files and then build 3D structural models which are used for the start point of 3D rebar auto-placing. After rebar auto-placing, each members of the 3D structural model have rebar information belonging to them. It means that the rebar information can be used for the afterward works such as quantity-survey, manufacturing and fabrication of rebars. Rebar Hub is showing outstanding performance while applying to practical projects. It has almost five times productivity and reduces the rebar loss up to 3~8% of the initially-surveyed amount of rebar.

• Journal of the Korea Institute of Building Construction
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• v.5 no.4 s.18
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• pp.99-106
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• 2005

With labor shortage and high-wage, the construction cost is rising and the construction-business is dull, demanding the construction environment of Korea to raise profitability through major cost savings and rationalization of construction management. Therefore, in this study, to improve many problems found in calculating rebar quantity for capital expenditure programming which is considered the beginning stage of rebar work. and to improve problems such as no grasping of rebar loss due to lack of systematic management in order/purchase stage and construction management stage, a rebar information-management-system was found and preyed. The relation database was designed for the rebar information management system by analyzing work process of a rebar manufacturing plant, as the rebar information that is necessary in a rebar manufacturing plant if similar to that of a purchasing department of general construction company. The Proposed rebar information management system was implemented in two large rebar production plants. The implementation of the proposed system showed that the system increased work efficiency, reduced the management manpower, and improved the project-integrated management

• Journal of the Korea Institute of Building Construction
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• v.23 no.4
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• pp.485-496
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• 2023

Precise construction cost estimation is paramount to determining the total construction expense of a project prior to the initiation of the construction phase. Despite this, manual quantification and cost estimation methods, which continue to be widely used, may result in imprecise estimation and subsequent financial loss. Given the fast-paced and efficiency-demanding nature of the construction industry, trustworthy quantity and cost estimation is essential. To mitigate these obstacles, this research is focused on establishing an automated quantity estimation algorithm, particularly designed for the main rebar of beams which are recognized for their complicated reinforcement configurations. The exact quantity derived from the proposed algorithm is compared to the manually approximated quantity, reflecting a variance of 10.27%. As a result, significant errors and impending financial loss can be averted. The implementation of the findings from this research holds the potential to significantly assist construction firms in quickly and accurately estimating rebar quantities while adhering strictly to applicable specifications and regulatory requirements.

• Corrosion Science and Technology
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• v.4 no.3
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• pp.81-88
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• 2005

The effects of rebar corrosion on the structural behaviour of reinforced concrete structures were discussed based on recent experimental investigation. The load carrying capacity of the deteriorated beams was quantitatively estimated by evaluating the degree of rebar corrosion in terms of the average cross-sectional loss of longitudinal reinforcing bars and bond deterioration between corroded reinforcing bars and concrete.