An Introduction to Structures of Uniform Response

Structures of Uniform response (SUR) are highly optimized mathematical models that canbe used to assess the efficiencies of geometrically identical structures with similar boundary conditionsand lateral loading. In SUR, groups of primary members such as beams, columns and braces respondidentically to external forces. Individual elements of the same group of members are designed tosimultaneously undergo identical deformations and to develop equal stresses throughout the structure.SUR act as frameworks of equal strength and stiffness in which members of the same group share thesame demand-capacity ratios regardless of the location and number of elements within the system. Thefundamental idea behind SUR development is that structural response is largely a function of designand construction, rather than numerical analysis. Both strength and stiffness are induced rather thaninvestigated. The proposed methodology is particularly suited to all types of regular structures withproven hysteretic behavior. While the present article has focused attention on earthquake resistingmoment frames, the same procedures could be extended, without loss of generality, to other forms ofearthquake resisting structures such as Eccentric and Concentric Braced Frames, Special Truss MomentFrames, Shear Walls and Hybrid systems. The methodology reduces the otherwise complicated task ofstructural optimization to direct design through simple statics and recommended rules of generalapplication.

Keywords:

uniform drift , rocking wall , moment frame , seismic , plastic design