Study And Application Of Reinforcement The Feasibility Of The Substitution From US To GB In AP1000 Nuclear Power Project

Knowing that nuclear power is a kind of safe and clean energy,China has been committed to development of nuclear power since the Reform and Opening-up in an effort to combat pollution generated by traditional energy sectors.As construction of nuclear power projects getting more momentum across the country,rebar engineering has become a focus of nuclear power projects.The rebar used in AP1000 nuclear power projects is Grade 60420 per ASTM A615(hereinafter referred to as “American Standard rebar”),which is procured from overseas suppliers and features long procurement cycles and higher costs,and is not conducive for schedule control.It is true that some domestic manufacturers supply American Standard rebar,but given that the specifications available in domestic market are not complete,combined by the fact that the amounts of different types of rebar may vary from projects to projects,the domestically manufactured American Standard rebar could not meet the market demands,let alone their costs that are much higher than the GB Standard equivalence.Based on comparative analysis on properties,anchoring and connection engineering requirements of American Standard rebar and GB Standard rebar,as well as the practical substitution of rebar in AP1000 projects,this paper focuses on a systematic study on the feasibility and economy of substituting American Standard rebar with GB Standard rebar,and comes to the following conclusions:1.The comparison between American Standard rebar and GB Standard rebar suggests that the strength and anchoring property of GB Standard rebar meet the requirements of American Standard,and there is no need to select the greater from ACI and GB.In the comparison between ACI and GB in terms of the anchoring and overlapping length,the selected values of ACI are greater than GB in some cases,while in other cases those of GB are greater.As to the minimal strength of the welding connections and the sleeve connections,GB Standard rebar is higher than American Standard rebar.In construction practice,the substitution of rebar for anchoring also free contractors from the trouble of referring to the substitution form,which in return is conducive to the application of rebar and help further reduce errors.2.By comparing the American Standard and the GB Standard on rebar,it could be found that the two share much in common as they are fundamentally generic in structural mechanics and engineering.Substitution of the two types of rebar helps reduce the complexity of design drawings as the sketch of rebar could be clearly shown on the construction drawing.This makes the contractors who are familiar with GB Standards more comfortable and confident,thus realizing connectivity between the two materials.Quality control and on-site verification of the materials used at construction site also contribute to successful substitution of the rebar.3.Researches on the substitution of the rebar in the main structures and all disciplines of AP1000 projects have found that the substitution practice applies to such common types of steels as angle steel,channel steel and steel plates.This makes procurement of the rebar required for nuclear island construction easier,reduces construction cost,makes it more convenient for construction of AP1000 project in China,and increases the economic competitiveness of civil work of AP1000 projects.The substitution proposal,once approved by the design entity,can greatly reduce the procurement cycle of the rebar required,shorten the preparation time,reduce the costs,and secure better economic and social benefits.