Abstract
This report presents the results of continuous composite beam tests for the purpose of some clarification of stiffness and behavior on partial composite beams with negative moment subjected to vertical loads. Considering only six specimens with 3/8-in. stud connectors in this experiment it may not be generalized to apply these results to all composite beams with larger scale studs. However, the following conclusions may be drawn from the investigation reported herein : 1. In the spacing of the stud connectors, the difference in stiffness increases with increasing the load but we can make that there is no remarkable difference in stiffness. Generally speaking, there is no influence of spacing the stud connectors on stiffness of composite beams. It seems to be quite all right in practical application to space the stud connectors uniformly. 2. Generally, in composite beams, as the degree of partial shear connection becomes higher, steel beams act more compositely with concrete slabs and stiffness becomes higher. However, that tendency must become gentler in composite beams with more and more high degrees of partial shear connection. 3. Composite beams with extremely low degrees of partial shear connection like the U16 specimen are not unity and are considerably lower in stiffness than beams with above 50% shear connection. In the U16 specimen a few stud connectors were broken about the same time before the theoretical collapse load. Considering toughness we are not in a position to urge composite beams to be combined by extremely low degrees of partial shear connection as good.
