劉 朋, 徐敬文, 寧寶寬, 金生吉
(沈陽(yáng)工業(yè)大學(xué) 建筑與土木工程學(xué)院, 沈陽(yáng) 110870)
OSB板紋理對(duì)連接性能的影響*
劉 朋, 徐敬文, 寧寶寬, 金生吉
(沈陽(yáng)工業(yè)大學(xué) 建筑與土木工程學(xué)院, 沈陽(yáng) 110870)
冷彎薄壁型鋼; 定向刨花板; 垂直紋理; 水平紋理; 靜力加載; 連接剛度; 連接試驗(yàn); 破壞模式
1.1 試件制作
試件采用C型截面冷彎薄壁型鋼骨架柱和定向刨花板,通過(guò)自攻螺釘連接,如圖1所示(單位:mm).定向刨花板尺寸為250 mm×500 mm,厚度為11 mm,冷彎薄壁型鋼骨架柱長(zhǎng)度為300 mm,厚度為11 mm,截面尺寸見(jiàn)圖1c.
1.2 試驗(yàn)材料
試驗(yàn)采用INSTRON?4482測(cè)試設(shè)備,保持勻速加載.骨架柱采用600S162-54型,由于表面鍍鋅層會(huì)影響拉伸試驗(yàn),制作成標(biāo)準(zhǔn)拉伸試件前都進(jìn)行了去鋅處理,試驗(yàn)材料參數(shù)如表1所示.自攻螺釘均采用8號(hào)螺釘,長(zhǎng)度為49 mm.
圖1 試件及立柱截面圖
表1 骨架柱材料參數(shù)
1.3 試驗(yàn)裝置和測(cè)點(diǎn)
冷彎薄壁型鋼C型骨架柱固定在底部基座,側(cè)面與定向刨花板自攻螺釘連接,卡鉗與定向刨花板上部采用多點(diǎn)螺釘連接,確保提供居中的垂直上拉力,卡鉗另一端與全數(shù)字液壓伺服試驗(yàn)機(jī)MTS固定.位移計(jì)固定在底部基座,上部與MTS相連,試驗(yàn)加載裝置如圖2所示.采用ASTM A370標(biāo)準(zhǔn),保持速率為1.27 mm/min勻速加載,直到試件發(fā)生明顯破壞后停止加載.
垂直紋理與水平紋理試件的破壞形態(tài)均為螺釘周圍定向刨花板斷裂,未見(jiàn)螺釘從立柱拔出破壞或螺釘剪切破壞.荷載作用初期,試件處于彈性階段,變形較小;隨著荷載的增加,對(duì)于垂直紋理試件,當(dāng)荷載達(dá)到75%極限承載力時(shí),定向刨花板發(fā)出木纖維斷裂的聲響,螺釘下方一部分木質(zhì)纖維發(fā)生剪切破壞;隨著荷載繼續(xù)增加,木質(zhì)纖維被剪斷;當(dāng)荷載達(dá)到極限荷載時(shí),定向刨花板纖維被拉出板外,試件破壞,如圖3a、b、c所示.對(duì)于水平紋理試件,當(dāng)荷載達(dá)到70%極限承載力時(shí),定向刨花板發(fā)出微響,自攻螺釘對(duì)刨花板的木質(zhì)纖維產(chǎn)生明顯剪切剝離破壞;當(dāng)荷載達(dá)到極限承載力時(shí),螺釘下部的定向刨花板有木質(zhì)纖維被拉斷,同時(shí)伴隨著清脆的響聲,試件破壞,如圖3d、e、f所示.
圖2 試驗(yàn)加載裝置
圖3 試件破壞模式
試驗(yàn)得出的結(jié)論是垂直紋理試件承載力比水平紋理試件承載力高出約10%,水平紋理試件的連接剛度比垂直紋理試件高出約40%,試件的設(shè)計(jì)參數(shù)及試驗(yàn)結(jié)果如表2所示.
表2 試件設(shè)計(jì)參數(shù)及試驗(yàn)結(jié)果
試驗(yàn)得到連接試件的荷載與變形關(guān)系曲線如圖4所示.荷載作用初期,荷載與變形基本呈線性關(guān)系,試件處于彈性階段;隨著荷載的增加,試件取得最大荷載后,荷載急劇下降,荷載與位移關(guān)系曲線無(wú)明顯屈服,說(shuō)明其延性較差.垂直方向紋理連接試件在初始剛度時(shí)有一定的離散性,主要是由于定向刨花板的制作工藝所造成的,刨花板無(wú)法絕對(duì)均質(zhì),因此,試驗(yàn)中會(huì)造成個(gè)別試件的剛度和承載力存在差異(如SOC-V2和SOC-V3).荷載與變形關(guān)系曲線有“抖動(dòng)”,表現(xiàn)為荷載突然降低并且位移增大(如SOC-V1、SOC-V2和SOC-V5).試驗(yàn)中觀察發(fā)現(xiàn),“抖動(dòng)”一般出現(xiàn)在臨近荷載峰值,由于垂直紋理定向刨花板的螺釘相對(duì)運(yùn)動(dòng)方向與木纖維的方向平行,纖維層間膠體相連纖維的角度并不完全一致,因此,當(dāng)某層纖維剪斷時(shí),此時(shí)荷載就會(huì)驟然下降,位移增大,之后螺釘又碰到未被剪斷的纖維,又可以繼續(xù)承受荷載.其中,SOC-H3取得了最大承載力2.48 kN,其余試件都在1.8 kN波動(dòng).此外,與垂直紋理定向刨花板連接試件的荷載與變形關(guān)系曲線相比,水平方向紋理連接試件的初始剛度差異較小,但承載力相對(duì)較低.
圖4 試件荷載變形曲線
通過(guò)對(duì)10個(gè)定向刨花板與冷彎薄壁型鋼骨架柱的連接試驗(yàn)進(jìn)行研究,并對(duì)試驗(yàn)結(jié)果進(jìn)行分析,得到如下結(jié)論.
1) 水平紋理和垂直紋理的試件破壞形式不同,水平紋理試件呈現(xiàn)定向刨花板纖維剪切破壞并發(fā)生剝離;垂直紋理試件破壞模式為木質(zhì)纖維的撕裂.
2) 垂直紋理試件承載力比水平紋理試件承載力提高約10%,水平紋理試件的連接剛度比垂直紋理試件提高約40%,垂直紋理試件承載力相對(duì)較高,水平紋理試件的剛度相對(duì)較大.
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(責(zé)任編輯:鐘 媛 英文審校:尹淑英)
Influence of OSB texture on connection performance
LIU Peng, XU Jing-wen, NING Bao-kuan, JIN Sheng-ji
(School of Architecture and Civil Engineering, Shenyang University of Technology, Shenyang 110870, China)
In order to solve the problem that the horizontal and vertical texture of oriented strand board (OSB) will affect the mechanical connection performance of cold-formed thin-walled C-type steel column, the static tensile tests for 10 OSB and cold-formed thin-wall C-type steel column were carried out, and the influence of horizontal and vertical texture of OSB on the failure mode, connection stiffness and ultimate load capacity was analyzed. The results show that the specimen with vertical texture exhibits the fiber fracture damage, and the load capacity is about 10% higher than that of the specimen with horizontal texture. In addition, the specimen with horizontal texture exhibits the wooden fiber shear failure, and the connection stiffness is about 8% higher than that of the specimen with vertical texture. The tests can provide the design reference for the cold-formed thin-wall steel-OSB structures.
cold-formed thin-walled steel; oriented strand board (OSB); vertical texture; horizontal texture; static loading; connection stiffness; connection test; failure mode
2016-04-06.
遼寧省自然科學(xué)基金資助項(xiàng)目(2015020583); 遼寧省科技廳計(jì)劃項(xiàng)目(LJQ2013016); 遼寧省教育廳計(jì)劃項(xiàng)目(201564068); 沈陽(yáng)工業(yè)大學(xué)博士培育基金資助項(xiàng)目(50010101).
劉 朋(1983-),男,遼寧盤(pán)錦人,講師,博士,主要從事冷彎薄壁型鋼結(jié)構(gòu)等方面的研究.
10.7688/j.issn.1000-1646.2017.03.21
TU 398
A
1000-1646(2017)03-0357-04
*本文已于2016-12-22 17∶40在中國(guó)知網(wǎng)優(yōu)先數(shù)字出版. 網(wǎng)絡(luò)出版地址: http:∥www.cnki.net/kcms/detail/21.1189.T.20161222.1740.026.html