Experimental study of concrete filled cold-formed steel tubular stub columns

Abstract

An experimental programme was conducted to investigate the compressive behaviour of concrete-filled cold-formed steel tubular (CFCFST) stub columns with thicker tubes. A total of 30 CFCFST stub columns were tested. The cold-formed square hollow section (SHS) tubes included unstiffened sections and longitudinally inner-stiffened sections using different stiffening methods. Two tubular thicknesses of 6mm and 10mm were considered. The overall nominal dimension of the steel section was 200×200mm, and the length of the stub columns was 600mm. Normal concrete and self-consolidating concrete with a nominal compressive strength of 30MPa were used to fill the cold-formed SHS steel tubes. The effects of the stiffeners on the rigidity, ductility, failure mode and average sectional strength of the CFCFST specimens were examined. The measured strengths of the CFCFST specimens were also compared with the predicted capacities using methods in various codes including AISC, BS5400, EC4, and DBJ and from a finite element (FE) analysis. Results demonstrate that the inner stiffeners affect the deformability, failure mode and overall strength of the stub columns with the 6mm-thick tubes more significantly. The DBJ code method is comparatively the best in predicting the strength capacity. Using the validated FE model, an extended analysis has been conducted and this has provided further insight into the mechanical behavior of the CFCFST specimens.

Prediction of Ultimate Load of Rectangular CFST Columns Using Interpretable Machine Learning Method

“…To date, rectangular CFST members have been employed in many constructions such as buildings, bridges, and underground stations because of their strong moment resistance [13] and simple beam-column joints [10,14]. Moreover, with a given sectional size, rectangular CFST members exhibit greater stiffness than circular or elliptical members [15][16][17]. Although the design process for rectangular CFST columns is set forth in many current codes such as Eurocode 4 [18], AISC [19], and ACI [20], up until now, the axial behavior of rectangular CFSTmembers has received crucial attention from researchers/engineers.…”

A Novel Hybrid Model Based on a Feedforward Neural Network and One Step Secant Algorithm for Prediction of Load-Bearing Capacity of Rectangular Concrete-Filled Steel Tube Columns

“…For an illustration purpose, a set of input data gathered from Refs. [ 65 , 79 , 85 , 86 , 90 , 92 ] was used and the values of inputs are indicated in Table 8 below, together with the experimental value of N u , as well as the prediction by using: (i) existing empirical equations (see Equations (7)–(9)); (ii) SVM, FL, EBT models; and (iii) FNN-OSS model. For a comparison purpose, an indicator Δ was computed as below: where and are the predicted and experimental values of N u , respectively.…”

Life-cycle based analytical theory of concrete-filled steel tubular structures and its applications

“…约束效应系数(式(1))的 概念被拓展应用于新型钢管混凝土, 以研究不同材料 或 组 成 部 分 之 间 的 相 互 作 用 , 如 椭 圆 形 钢 管 混 凝 土 [19] 、中空夹层钢管混凝土 [22] 、内置FRP(fibre reinforced polymer/plastics)管钢管混凝土 [30] 、带加劲肋钢 管混凝土 [31] 、内置型钢钢管混凝土 [32] 、L形钢管混凝 土 [33] 、预制装配式钢管混凝土 [34] , 以及新型管材(如不 锈钢管、高强钢管)和/或新型内填混凝土材料(高强混 凝土、海水海砂混凝土)构成的钢管混凝土 [35~38] . 式(2)所示的核心混凝土本构模型被拓展用于中空 夹层钢管混凝土柱 [22] 、内置FRP管钢管混凝土柱 [30] 、 带加劲肋钢管混凝土柱 [31] 、内置型钢钢管混凝土 [32] 、 不锈钢管混凝土柱 [36] 、螺旋焊钢管混凝土柱 [39] 、哑铃 型钢管混凝土构件 [40] 、FRP约束钢管混凝土柱 [41] 、中 空型外壁钢板-混凝土组合桥塔塔柱 [42] 、五边形钢管 混凝土翼缘组合梁 [43] 等的静力性能, 不锈钢管混凝土 柱 [44] 和部分填充混凝土矩形钢管混凝土柱 [45] 的抗冲击 性能, 以及L形钢管混凝土混合构件 [33] 、预制装配式钢 管混凝土柱 [34] 等的抗震性能研究. 钢管混凝土构件承 载力计算方法被拓展用于内置FRP管钢管混凝土柱 [30] 和钢管海水海砂混凝土柱 [37] 的承载力计算方法的提 出.…”