Composite effects on rotational constraints of a double-beam system reinforced with beam-end concrete

Development of Optimal Design Method for Steel Double-Beam Floor System Considering Rotational Constraints

“…Figure 4 shows the relationship between the stiffness ratio (µ), defined as the ratio of the rotational stiffness of the connection (K R ) to the flexural stiffness of the double-beam (K F ), and the end-fixity factor (r), defined as the fixed end moment to the negative moment generated at the connection. From the experimental study for the steel double-beam floor system [7], the connection comprised of the steel double-beam and the concrete panel corresponding to the connection of the DBO system represents a rotational constraint equivalent to a code conforming rigid connection suggested by ANSI/AISC 360 (American National Standards Institute/American Institute of Steel Construction) [27], as shown in Figure 4. Thus, the connection of the DBO system can be modeled as a rigid connection in the structural analysis based on the experimental result.…”

“…To secure the rotational constraints equivalent to the rigid connection, the value of stiffness ratio should be less than 0.05 as shown in Figure 4. In previous work [7], the flexural behavior of the double-beam floor system was experimentally evaluated according to the presence of the concrete panel, and the stiffness ratio of the composite connection was determined to 0.032 (see reference [7] for the detailed information about the…”

“…To secure the rotational constraints equivalent to the rigid connection, the value of stiffness ratio should be less than 0.05 as shown in Figure 4. In previous work [7], the flexural behavior of the double-beam floor system was experimentally evaluated according to the presence of the concrete panel, and the stiffness ratio of the composite connection was determined to 0.032 (see [7] for the detailed information about the stiffness ratio). In addition, as the stiffness ratio is independent of the boundary conditions, in this study, the stiffness ratio of the composite connection in the DBO system was fixed at 0.032 based on the previous work [7].…”

“…Recently, steel-concrete composite floor systems [6][7][8] have mainly been used to reduce the material quantity as the composite action of two materials can increase the flexural capacity in terms of stiffness and strength [9][10][11]. The initially developed steel-concrete composite floor systems [12,13] were aimed at reducing the floor height and improve the constructability, so beam-column connections were pinned using bolts.…”

“…To improve the constructability of the beam-column connection in the steel-concrete composite floor system, we proposed a steel double-beam floor system in previous works [7,19] as shown in Figure 1. The steel double-beam floor system is a composite floor system composed of steel-reinforced concrete (SRC) columns, steel beams, and concrete panels.…”