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(1 西安科技大學(xué)建筑與土木工程學(xué)院, 西安 710054; 2 西安建筑科技大學(xué)土木工程學(xué)院, 西安 710055)
[摘要]為了更好地研究大氣環(huán)境中的混凝土結(jié)構(gòu)在凍融作用下的耐久性能,采用氣凍氣融的試驗方法,對足尺(150mm×300mm×2 700mm)鋼筋混凝土梁在不同凍融循環(huán)次數(shù)作用后的抗彎承載力進(jìn)行了研究,分析了凍融對鋼筋混凝土梁在靜荷載作用下的裂縫發(fā)展規(guī)律、開裂荷載、極限荷載、跨中撓度以及混凝土截面應(yīng)變的影響。研究結(jié)果表明:經(jīng)過凍融循環(huán)作用后的鋼筋混凝土梁在靜荷載作用下,其裂縫發(fā)展規(guī)律與未凍融梁基本一致;隨著凍融循環(huán)次數(shù)的增加,開裂荷載、極限荷載以及跨中撓度逐漸降低,凍融循環(huán)150次時,開裂荷載下降為未凍融時的60%,極限荷載下降為未凍融時的86-7%,跨中撓度下降為未凍融時的79%;混凝土截面應(yīng)變符合平截面假定,且隨著凍融循環(huán)次數(shù)增加,混凝土受壓區(qū)高度有所增加。
[關(guān)鍵詞]氣凍氣融; 開裂荷載; 極限荷載; 跨中撓度; 截面應(yīng)變
中圖分類號:TU375-1文獻(xiàn)標(biāo)識碼:A文章編號:1002-848X(2018)22-0062-05
Experimental research on flexural bearing capacity of RC beam under air-freezing and air-thawing actions
Guan Xiao1, Niu Ditao2, Li Qiang1, Xiao Qianhui1
(1 School of Architecture and Civil Engineering, Xi′an University of Science and Technology, Xi′an 710054, China;2 School of Civil Engineering, Xi′an University of Architecture and Technology, Xi′an 710055, China)
Abstract:In order to better study the durability of concrete structures in the atmosphere under freezing and thawing, the test method of air-freezing and air-thawing was used to study flexural bearing capacities of the full-scale (150mm×300mm×2 700mm) reinforced concrete beams in different freeze-thaw cycles. The effects of freezing and thawing on the crack development law, cracking load, ultimate load, mid-span deflection and concrete cross-section strain of reinforced concrete beams under static load were analyzed. The study results show that the crack development law of reinforced concrete beams subjected to freeze-thaw cycles is basically the same as that of beams without freeze-thaw cycles. With the increase of freeze-thaw cycles, the cracking load, ultimate load and mid-span deflection gradually reduce. When the freeze-thaw cycle time is 150, the cracking load decreases to 60% at the time of non-freeze-thaw cycle, and the ultimate load decreases to 86-7% at the time of non-freeze-thaw cycle, and the mid-span deflection decreases to 79% at the time of non-freeze-thaw cycle. The concrete cross-section strain conforms to the flat section assumption, and as the number of freeze-thaw cycles increases, the concrete compression zone height increases.
Keywords:air-freezing and air-thawing; crack load; ultimate load; mid-span deflection; cross-section strain
*國家自然科學(xué)基金(51278403),教育部長江學(xué)者和創(chuàng)新團(tuán)隊發(fā)展計劃(IRT13089)。
作者簡介:關(guān)虓,博士,講師,Email: 86484869@qq.com。