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（河北工業(yè)大學(xué)土木與交通學(xué)院， 天津 300401）

［摘要］為了研究軸壓重復(fù)荷載作用下箍筋約束混凝土L形柱的性能，進(jìn)行了5根箍筋約束混凝土L形短柱的軸心重復(fù)受壓試驗(yàn)和1根箍筋約束混凝土L形短柱的單調(diào)軸心受壓試驗(yàn)，研究了L形柱的破壞特征、滯回曲線、骨架曲線、應(yīng)變發(fā)展和延性，并建立了延性系數(shù)計(jì)算公式。試驗(yàn)結(jié)果表明，軸壓重復(fù)荷載作用下L形柱的破壞特征與單調(diào)荷載作用下相似，隨著配箍特征值增大，破壞類型由斜向破壞轉(zhuǎn)變?yōu)榭v向壓碎破壞，峰值荷載及相應(yīng)位移增大，骨架曲線下降段越平緩，延性越好。延性系數(shù)計(jì)算結(jié)果與試驗(yàn)結(jié)果吻合良好。采用有限元軟件ANSYS分析了軸壓重復(fù)荷載作用下箍筋對(duì)L形柱核心混凝土的約束作用，約束機(jī)理與單調(diào)荷載作用下相似。建立了約束混凝土抗壓強(qiáng)度、峰值應(yīng)變與配箍特征值、箍筋有效約束系數(shù)的關(guān)系表達(dá)式，計(jì)算結(jié)果與試驗(yàn)結(jié)果吻合良好；并在此基礎(chǔ)上建立了L形短柱軸壓承載力計(jì)算公式，與試驗(yàn)結(jié)果比較，計(jì)算結(jié)果偏于安全，可用于軸壓重復(fù)荷載作用下箍筋約束混凝土L形短柱的軸心受壓承載力的分析。

［關(guān)鍵詞］L形柱； 軸壓重復(fù)荷載； 配箍特征值； 延性； 約束混凝土

中圖分類號(hào)：TU375-3文獻(xiàn)標(biāo)識(shí)碼：A文章編號(hào)：1002-848X(2019)06-0079-07

Research on the performance of L-shaped concrete columns confined by stirrups under axial repeated loads

Wang Xiaowei， Wei Shihua

（School of Civil Engineering and Transportation, Hebei University of Technology, Tianjin 300401, China）

Abstract:To study the performance of L-shaped concrete columns confined by stirrups under axial repeated loads, axial repeated loads tests of 5 L-shaped concrete short columns confined by stirrups and  axial monotonic load test of one specimen  were carried out. The failure characteristics, hysteresis curve, skeleton curve, strain development, ductility of L-shaped columns were studied and the formulas of ductility coefficient was established. The test results show that the failure characteristics of L-shaped columns under axial repeated loads are similar to those under axial loads. With the increase of stirrup characteristic value, the failure type changes from oblique failure to longitudinal crushing failure; the peak load and corresponding displacement of L-shaped columns increase; the descending segment of skeleton curves turns to be more flat and ductility becomes better. The calculated results of ductility coefficient are in good agreement with the experimental results. The restraint effect of stirrup on core concrete of L-shaped column was analyzed by using finite element software ANSYS, and the restraint mechanism is similar with axial load. The relation expressions between the compressive strength, peak strain and stirrup characteristic value, stirrup effective constraint coefficient were established; the calculated results are in good agreement with the experimental results. On this basis, the calculation formula of axial compression bearing capacity of L-shaped concrete short columns was established. The calculated results are relatively safe compared with the experimental results, and it can be used to analyze the axial compression bearing capacity of L-shaped concrete  short columns confined by stirrups under axial repeated loads.

Keywords:L-shaped column; axial repeated load; stirrup characteristic value; ductility; confined concrete