EXPERIMENTAL INVESTIGATION INTO ULTIMATE BEHAVIOR OF FRAMES WITH COMPOSITE LATTICE GIRDERS

Abstract

Test results of composite lattice girders with concrete slabs and companion steel girders under cyclic antisymmetrical bending loads are discussed. Significant conclusions may be summarized as follows: (1) The effective length factor for lateral buckling of the lower chord is reduced owing to an restraining effect supplied by the concrete slab. (2) By using assumptions that a plane section remains plane during bending, simple equations can be formulated to predict the elastic stiffness and ultimate bending capacity of composite lattice girders with good accuracy. (3) Since upper chords of composite lattice girders are prevented from buckling by slabs, one end of a lower chord buckles while the other end is forced to yield in tension. Therefore, composite lattice girders show more stable post-buckling hysteretic behavior over steel girders.