Double Overlap Beam

Beams with continuity over supports may be fabricated and erected by means of prismatic members of somewhat longer lengths than the spacing between supports, and is simply lapped and connected (bolted, etc.) to the corresponding member in the adjacent span. The continuous beam is composed of a doubled section over the supports, where the bending moment is ordinarily greatest, and a single section over the midspan. Charts are presented of parameters required for the moment-distribution analysis of continuous beams formed of members with double sections at one or both ends, the equations for the connection force required between the adjacent elements of the beam, and the analytical procedure. By judicious arrangement of overlap lengths of adjacent members, the resulting moments at critical points in the beam can be manipulated to reduce the bending moment at maximum points, while increasing the moment at minimum points.