An experimental study of the Behavior of Coupler Mechanical Tensile Splices and Economical Comparation

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: An experimental study of the Behavior of Coupler Mechanical Tensile Splices and Economical Comparation

ارائه دهنده: Provider: Mehdi soltani saber

اساتید راهنما: Supervisors: dr.mostafa moghadasi

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: dr. nili and dr. rezaie

زمان و تاریخ ارائه: Time and date of presentation: 2021

مکان ارائه: Place of presentation: onile

چکیده: Abstract: Nowadays, reinforced concrete structures have received more attention than steel structures due to their economic justification. In this type of concrete structures, there is no use of continuous rebars for reasons such as limited production length limit, transport and practice floor by floor, Therefore, in order to connect the rebars properly, it is necessary to splice the rebars. There are several methods for splicing rebar, such as mechanical splices, welded splices, backing splices and Overlapping. Overlapping is currently the most common type of connection. Coupler mechanical splice has been used to reduce splice length, make changes and compare economically with Over;appings in this research. This research has been done in 6 general stages. The first step is performed on rebars with 400 (A3) tread, without splices to obtain their mechanical properties. At this stage, the average yield stress and rupture of the rebars are obtained. The second stage of experiments to obtain the mechanical characteristics of mechanical coupler splices with standard coupler is reviewed. In the third stage of this research, the shortening of the on this stage, by reducing the threads, it has not met the requirements of the regulations based on 125% of the surrender force-splice length and the use of thread reinforcement adhesives have been investigated. In the fourth step, PS77 thread reinforcement adhesive was used to strengthen the shortened threads which was associated with increased rupture stress but acceptable reliability coefficients were not obtained. For this reason, in the fifth step, Vaiken glue has been used to strengthen the shortened threads, and acceptable results have been obtained. In the sixth step, a sample with a Overlappings is tested. The yield stresses in the types of splices with and without splices did not change much, but the final stresses in the types of splices, especially the Overlappings, decreased. The modulus of elasticity of the rebars has decreased between 40 and 70% after splice. The ductility ratio decreases with increasing yield strain and decreasing the final strain of spliced rebars. The area below the stress-strain diagram of the spliced specimens is greatly reduced due to the reduction of the final strain. The amount of energy absorbed by the spliced rebars is reduced, This reduction in Overlapping has reached 95%. The use of mechanical coupler splices reduces