BEHAVIOR OF SEMI-RIGID COMPOSITE CONNECTIONS.

Abstract

The new Load and Resistance Factor Design (LRFD) Specification recognizes two types of framing: Type FR (fully restrained) is the same as Type 1 in the 1978 Specification, and Type PR (partially restrained) combines Types 2 and 3. If the ultimate moment capacity and its moment-rotation characteristics in the service load range can be easily determined, the design of semi-rigid frames could be greatly simplified under the LRFD Specification. The results of an experimental program reported here indicate this behavior can be achieved by semi-rigid composite connections. Composite semi-rigid connections offer moment-rotation curves which are very stiff and fairly linear in the service range, and have an easily calculated ultimate capacity. Moreover, the system exhibits large ductilities, good energy dissipation capacity, and ease of construction.