本文關(guān)鍵詞： 橋梁工程 “上”形截面鋼梁 整體穩(wěn)定性 整體穩(wěn)定系數(shù) 偏跨比　出處：《建筑科學(xué)與工程學(xué)報(bào)》2017年05期 　論文類(lèi)型：期刊論文

【摘要】：為對(duì)"上"形截面鋼梁彎扭聯(lián)合作用下的整體穩(wěn)定性進(jìn)行分析,采用有限元數(shù)值計(jì)算方法,通過(guò)失穩(wěn)模態(tài)考慮構(gòu)件L/1 000(L為跨徑)的幾何初始缺陷,對(duì)比已有文獻(xiàn)試驗(yàn)結(jié)果,驗(yàn)證了模擬方法的正確性,在此基礎(chǔ)上,對(duì)跨中集中荷載和滿跨均布荷載作用下的簡(jiǎn)支"上"形截面鋼梁整體穩(wěn)定性進(jìn)行分析,通過(guò)曲線擬合給出了"上"形截面鋼梁整體穩(wěn)定系數(shù)計(jì)算公式,分析了荷載偏心距和跨徑對(duì)穩(wěn)定承載力及彎扭效應(yīng)分配的影響。研究結(jié)果表明:通過(guò)失穩(wěn)模態(tài)考慮構(gòu)件L/1 000幾何缺陷可以準(zhǔn)確地計(jì)算穩(wěn)定承載力;"上"形截面鋼梁整體穩(wěn)定系數(shù)的取值較國(guó)標(biāo)規(guī)范工字梁小,且均布荷載較集中荷載小;"上"形截面鋼梁的穩(wěn)定承載力隨著偏心距和跨徑的增加逐漸降低,且影響程度也逐漸變小;偏跨比較大時(shí),失穩(wěn)破壞主要由扭轉(zhuǎn)效應(yīng)引起,偏跨比較小時(shí),則主要由彎曲效應(yīng)引起;集中荷載較均布荷載更容易使"上"形截面鋼梁失穩(wěn);使用《冷彎薄壁型鋼結(jié)構(gòu)技術(shù)規(guī)范》(GB50018—2002)進(jìn)行"上"形截面鋼梁的整體穩(wěn)定性驗(yàn)算會(huì)偏于不安全。
[Abstract]:In order to analyze the overall stability of steel beam with "upper" section under the combined action of bending and torsion, the finite element numerical method is used. The geometric initial defects of the component L / 1 000 L are considered by the instability mode. The correctness of the simulation method is verified by comparing the experimental results. The overall stability of simply supported "upper" section steel beam under concentrated load and full span uniform load is analyzed, and the formula of overall stability coefficient of "upper" section steel beam is given by curve fitting. The effects of load eccentricity and span on the stability bearing capacity and the distribution of bending and torsion effect are analyzed. The results show that the stability bearing capacity can be accurately calculated by considering the geometric defects of the member L / 1 000 by considering the instability mode. The overall stability coefficient of steel beam with "upper" section is smaller than that of I-beam of GB standard, and the uniform load is smaller than that of concentrated load. With the increase of eccentricity and span, the stable bearing capacity of "upper" section steel beam decreases gradually, and the influence degree becomes smaller. When the span is large, the instability is mainly caused by torsional effect, but when the span is small, it is mainly caused by the bending effect. The concentrated load is more likely to make the steel beam with "upper" section unstable than the uniformly distributed load. Using the Technical Specification for Cold-Formed Thin-walled Steel structures (GB50018-2002) to check the overall stability of steel beams with "upper" section will be considered unsafe.
【作者單位】： 長(zhǎng)安大學(xué)公路學(xué)院;青海省交通科學(xué)研究院青藏高原公路建設(shè)與養(yǎng)護(hù)重點(diǎn)實(shí)驗(yàn)室;中交第二公路勘察設(shè)計(jì)研究院有限公司;
【基金】：交通運(yùn)輸部建設(shè)科技項(xiàng)目(2014 318 363 230) 陜西省交通運(yùn)輸廳科研項(xiàng)目(15-24K,16-29K)
【分類(lèi)號(hào)】：U441
【正文快照】： 0引言在橋梁鋼結(jié)構(gòu)中,鋼梁是最基本的受力構(gòu)件,往往在主軸平面內(nèi)承擔(dān)由橫向荷載所產(chǎn)生的彎矩、剪力以及荷載偏心時(shí)產(chǎn)生的扭矩作用,如果沒(méi)有設(shè)置足夠的平面外支撐,鋼梁的上翼緣在壓應(yīng)力作用下發(fā)生側(cè)向失穩(wěn)進(jìn)而帶動(dòng)整個(gè)截面發(fā)生側(cè)向彎曲和扭轉(zhuǎn),使構(gòu)件在未到達(dá)強(qiáng)度破壞之前就喪失

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