Experimental Behavior and Economic Cost of Tensile Rebar Splices Using Coupler and Forge Welding

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: Experimental Behavior and Economic Cost of Tensile Rebar Splices Using Coupler and Forge Welding

ارائه دهنده: Provider: Hamed karamlu

اساتید راهنما: Supervisors: Dr. Mostafa Moghadasi

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Dr. Fereydoon Rezaie-Dr.Amir RezaieSameti

زمان و تاریخ ارائه: Time and date of presentation: 2023

مکان ارائه: Place of presentation: Seminar 1- Civil Department

چکیده: Abstract: The use of reinforced concrete structures is increasing in Iran due to its optimal compressive strength, economic efficiency and durability. One of the most important issues in the implementation of reinforced concrete structures is the type of splice and its location, which strongly influences the behavior of reinforced concrete members. the rebar splice in reinforced concrete structures is the longitudinal connection of two rebars together so that it can withstand 125% of the Yield stress of the rebars. nowadays , in Iran, Lap splice is used to connecting reinforcements in most reinforced concrete structures. It can be said that the Lap splice is currently the most common type of Connection, which is done by placing the connecting bars of sufficient length side-by-side and usually tying them with steel wires. According to paragraph 9-21-4-1-2 of the ninth article of the National Building Regulations, edited in 1399, tensile and compressive bars with a diameter of more than 34 mm cannot be connected in a Lap spliceing. It is also forbidden to use a Lap spliceing in the joints of the beam to the column, at a length equal to twice the height of the cross section of the support and in places such as the foot of the columns where plastic joints can be formed. Also, since the stress in Lap splice is transferred by concrete, and given that concrete can be exposed to damage and there is a possibility of reducing its strength, this type of coating is not structurally appropriate compared to mechanical and welding joints in which the stress transfer to concrete does not depend. On the other hand, a significant percentage of the amount of bars consumed in the project is consumed for the length of the coating, which is not economically desirable; therefore, the use of alternative methods of The conventional method of splicing, lap splicing is inevitable, which can be referred to as appropriate mechanical or forging splices with acceptable behavior in structural elements as an alternative method of Lap splice. There are several benefits to using these types of splices in structural elements: (1) reduction in reinforcement congestion (which could increase construction quality significantly),(2) reduction in total weight of steel bars which is both economically and environmentally beneficial, (3) shortening the construction time, (4) connecting the wasted bars to reuse them.One of the most important concerns in reinforced concrete structures is the use of the appropriate method of splicing rebars due to its undeniable effect on the performance of structures, construction time and cost. Each of the standard coupler splices or the Forge Welding may be superior to each other in terms of the parameters mentioned above, especially the cost of the splice execution, as well as in terms of resistance to axial and lateral loads, ease of execution, availability of specialists and equipment needed to perform the splice, so in view of the mentioned material and the lack of empirical studies in the field of comparing the behavior of the standard coupler and Forge Welding, the study and laboratory research on this type of splice and the recognition of the advantages, disadvantages and comparing the economic cost of implementing them to each other is necessary. To this end, the study examined the experimental behavior and economic cost of tensile Rebar splices using couplers and Forge Welding. The Rebars used in this study were A3, and of each of the Rebars No. 16, 18, 20, and 22, one sample was considered as non-spliced samples, four samples were considered as coupler splices samples, and four other samples were considered as Forge Welding samples, with half of the spliced samples, without enclosure in concrete, and the other half of these samples were enclosed in concrete. A total of 4 samples without splices, 16 with mechanical splices, and 16 with Forge Welding were considered for use in direct traction testing and digital imaging Correlation process. After conducting experiments and calculating and comparing various parameters between mechanical and welded splices, mechanical splices perform better than Forge Welding in terms of most of the parameters compared, including Yield strain, Rupture stress, hardness and maximum load. It goes without saying that the Forge Welding splices absorbed more energy than mechanical splices. But in general, it can be concluded that mechanical splices perform better behaviorally than Forge Welding splices, and that they will also cost less and spend less time implementing these types of splices. on the other hand, Mechanical splices, are more reliable than Forge Welding splice.

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