A low-tech dissipative buckling restrained brace. Design, analysis, production and testing

This work aims to foster the mass use of buckling restrained braces, mainly in developing countries. To reach this goal, two major objectives are pursued: (i) to contribute to a better understanding of the structural behavior of such dissipators and (ii) to propose cheap and simple yet efficient devices, suitable for the intended applications. Such devices should be patent free. The research approach consists of three consecutive stages: (i) designing, producing and testing individually short length dissipators, (ii) taking profit of the gained experience to design, produce and test individually four larger prototype devices (near 3000 mm long) and (iii) designing, producing and testing on subassemblies, a number of full scale dissipators. The two first stages are completed while the third one is in progress; this paper concentrates on the second stage. The considered devices consist basically of a steel cylinder as dissipative core and a steel tube filled with mortar as buckling restrainer casing. The design and production issues are accounted for in an integrated way and all the adopted technical solutions are explained. A numerical analysis of the buckling behavior is carried out; it allows formulating design recommendations. The experiments consist of imposing on the prototype devices axial cycling strain up to failure. The results of the tests are described and discussed; they show that the devices performed satisfactorily. The main conclusion of this work is that it is possible to obtain a reasonably cheap, efficient, robust, low maintenance and durable prototype device requiring only a low-tech production process. Further research needs are identified.