Moment-Curvature Relationship of Concrete-Filled Square Steel Tube Beam-Columns Under Monotonic Loading

Shear force‐deformation relationship of concrete‐filled square steel tube beam‐columns under monotonic lateral loading

“…As illustrated in Figure 2B, the deformation of the elastoplastic part can be considered as a horizontal deformation ( p d) and a rotational deformation ( p h) due to uniform bending, and can be obtained from the M-/ relationship of Ref. [6] shown in Figure 3. The rotation angle ( p R 0 ) obtained by Equations (6) and 7is expressed by the following Equation (8).…”

“…[6] shown in Figure 3. The rotation angle ( p R 0 ) obtained by Equations (6) and 7is expressed by the following Equation (8). In this model, the length of the elasto-plastic part is constant, but it is necessary to consider that the length varies depending on the buckling length-section depth ratio and the axial compression ratio.…”

“…To simplify the stress state of the elasto‐plastic part, assuming the stress state for uniform bending, the bending strength and the deformation of the elasto‐plastic part are calculated from the M ‐ ϕ relationship model in Ref. [6]. where l is the shear span (in the case of double curvature loading, l = L /2), L is the clear span of beam‐column, e l is the length of elastic part, and p l is the length of elasto‐plastic part.…”

“…The rotation angle ( p R ) of the elasto‐plastic part due to the bending moment is estimated from the curvature according to the M ‐ ϕ relation model (see Figure 3) in Ref. [6]. The rotation angle ( e R m ) due to the bending deformation of the elastic part and the rotation angle ( R s ) due to the shear deformation over the entire column length are calculated as for the elastic state.…”

“…To enable the flexural‐shear behavior of short to slender beam‐columns to be evaluated with a single model, the column member is divided into elasto‐plastic parts at the column ends and a remaining elastic part. In the elasto‐plastic part, the deformation is evaluated based on the bending moment‐curvature (called M ‐ φ hereinafter) relationship proposed by the author 6 and by employing the newly proposed curvature magnification. This paper presents the proposed model and a method for evaluating the shear strength and deformation at each point in the proposed model, and compares the predicted and experimental results.…”