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(1 武漢理工大學(xué)基建處, 武漢 430070; 2 中建三局科創(chuàng)產(chǎn)業(yè)發(fā)展有限公司, 武漢 430100)

摘要: 為研究初始幾何缺陷對(duì)鋼梁內(nèi)嵌式預(yù)應(yīng)力組合梁抗火性能的影響,建立了鋼梁內(nèi)嵌式預(yù)應(yīng)力簡(jiǎn)支組合梁在高溫下非線(xiàn)性升溫過(guò)程受力行為的有限元模型. 通過(guò)考察梁的破壞形式、跨中撓度、側(cè)向位移、拉索張力以及梁的曲率等關(guān)鍵參數(shù)的變化,得到初始幾何缺陷對(duì)該預(yù)應(yīng)力組合梁抗火性能的影響機(jī)理. 分析結(jié)果表明:對(duì)于內(nèi)嵌鋼梁的預(yù)應(yīng)力簡(jiǎn)支組合梁,初始幾何缺陷形式可分為跨中彎扭屈曲和腹板局部屈曲兩種,其中跨中彎扭屈曲對(duì)該預(yù)應(yīng)力組合梁的抗火性能有一定影響. 初始幾何缺陷越大,該預(yù)應(yīng)力組合梁跨中撓度隨溫度升高而下降的速率越大,臨界溫度更低. 由于預(yù)應(yīng)力拉索會(huì)隨著組合梁變形協(xié)調(diào),因此初始幾何缺陷越大,同一溫度下拉索應(yīng)力與塑性應(yīng)變也將更大. 在高溫破壞時(shí),梁加載點(diǎn)處曲率最大,其次是跨中區(qū)段. 初始幾何缺陷形式影響了梁沿縱向的曲率分布,在第一階彎扭屈曲形式的初始幾何缺陷影響下,梁跨中曲率增大,但整體曲率所有下降;在第四階彎扭屈曲影響下,梁跨中曲率減小,但整體曲率有所增大.

關(guān)鍵詞: 抗火性能; 初始幾何缺陷; 預(yù)應(yīng)力筋; 鋼梁內(nèi)嵌式組合梁; 有限元模擬

中圖分類(lèi)號(hào):TU394 文獻(xiàn)標(biāo)志碼:A 文章編號(hào):1002-848X(2023)03-0080-07

DOI:10. 19701 / j. jzjg. 20210474

Effect of initial geometric defects on fire resistance of steel beam embedded prestressed composite beams

LIU Yuchen1, ZHENG Zhiyuan2, YAN Jihu2, NIE Jun2

(1 Infrastructure Development Office, Wuhan University of Technology, Wuhan 430070, China;2 China Construction Third Bureau Science and Technology Industry Development Co. , Ltd. , Wuhan 430100, China)

Abstract:To investigate the effect of initial geometric defects on the fire resistance of steel beam embedded prestressedcomposite beams, a finite element model of the stress behavior of steel beam embedded prestressed simply-supportedcomposite beams during nonlinear temperature rise at high temperature was established. The mechanism of the influence ofinitial geometric defects on the fire resistance of this prestressed composite beam was obtained by examining the changes ofkey parameters such as failure mode, mid-span deflection, lateral displacement, tensile tension and curvature of the beam.The analysis results show that for the prestressed simply-supported composite beam with embedded steel beams, the initialgeometric defects can be divided into two forms: mid-span buckling and web local buckling, among which the mid-spanbuckling has a certain influence on the fire resistance performance of the prestressed composite beam. The larger the initialgeometric defect is, the greater the rate of decrease of the spanwise deflection of this prestressed composite beam with theincrease of temperature, and the lower the critical temperature is. Since the presstressed tensile will coordinate with thedeformation of the composite beam, so the larger the initial geometric defect, the greater will be the tensile stress andplastic strain at the same temperature. At high temperature damage, the curvature is greatest at the beam loading point,followed by the mid-span section. The initial defect form affects the curvature distribution along the longitudinal direction ofthe beam. Under the influence of the initial geometric defects in the form of first-order bending and torsional buckling, thecurvature in the span increases, but the overall curvature all decreases; under the influence of the fourth-order bending andtorsional buckling, the curvature in the span decreases, but the overall curvature increases.

Keywords:fire resistance; initial geometric defects; prestressing tendons; steel beam embedded composite beam; finiteelement simulation

第一作者:劉雨晨,碩士,工程師,主要從事工程管理和組合結(jié)構(gòu)研究,Email:630751260@ qq. com.

[引用本文] 劉雨晨,鄭志遠(yuǎn),鄢吉虎,等. 初始幾何缺陷對(duì)鋼梁內(nèi)嵌式預(yù)應(yīng)力組合梁抗火性能的影響[ J]. 建筑結(jié)構(gòu),2023,53 ( 3):80-86. LIU Yuchen,ZHENG Zhiyuan,YAN Jihu,et al. Effect of initial geometric defects on fireresistance of steel beam embedded prestressed composite beams[J]. Building Structure,2023,53(3):80-86.