Experimental study of slender concrete-filled elliptical hollow section beam-columns

Abstract

Experiments on concrete-filled elliptical hollow section beam-columns have been conducted to examine their fundamental structural behaviour. A total of 27 specimens were tested -3 stub columns and 24 longer members of varying slenderness. Seven of the tested specimens also contained steel reinforcement. The specimens were loaded in compression, either concentrically or with different major or minor axis eccentricities.Measurements of the applied load, the strains at mid-height, the axial displacement and the lateral deflection at mid-height were recorded. Plots of load against the lateral deflection at mid-height and load against axial displacement are presented for the

Numerical analysis and design of slender concrete-filled elliptical hollow section columns and beam-columns

“…The three main experimental studies used for validation of the numerical model and the assessment of design proposals in the present study are [34][35][36]. The geometric and material properties, reinforcement ratios , nondimensional slenderness  (defined in Section 4.1) and ultimate loads recorded by [34][35][36] are summarised in Table 1. The cross-sectional geometry of the tested specimens is shown in Figure 1.…”

“…The cross-sectional geometry of the tested specimens is shown in Figure 1. A total of 48 tests from [34][35][36] were used for validation of the numerical model presented in Section 3.…”

“…In the experimental study described in [34], a total of 24 concrete-filled slender columns of 150 × 75 × 6.3 EHS cross-section and various lengths, either with or without steel reinforcement and loaded in compression either concentrically or eccentrically, were tested. The ends of the columns were fitted with knife-edges, resulting in the boundary conditions in the intended axis of bending and buckling being pinned-pinned while in the orthogonal direction, no end rotations were permitted.…”

“…The model was validated against the experimental results of [34][35][36] by comparing ultimate loads, load-deflection behaviour and failure modes. Once satisfactory agreement between the experimental and numerical results was achieved, an extensive parametric study comprising 360 simulations was conducted, in which the cross-sectional geometry, reinforcement ratio, reinforcement cover, column slenderness and load eccentricity were varied.…”

“…These studies provided a basis upon which design rules for steel EHS members have been formulated [28], including rules for compressive resistance [21], bending [23], flexural buckling [24] and shear [29]. In the context of concrete-filled elliptical hollow section (CFEHS) members, previous experimental studies include compression testing of stub columns [4,30,31], members in bending [32], concentrically-loaded slender columns [33] and eccentrically-loaded columns [34][35][36][37]. The behaviour of CFEHS columns in fire conditions was also examined by [35].…”