不同樑腹材料對杉木複合工字樑靜曲性質之影響

Effects of Web Materials on Flexural Properties of China Fir Composite I-Beams

賴政彥(Cheng-Yen Lai) ； 葉民權(Min-Chyuan Yeh)

《台灣林業科學》 17卷2期 (2002/06) Pp. 219-230

https://doi.org/10.7075/TJFS.200206.0219

摘要

本研究以杉木材爲樑翼構材，並分別使用合板、粒片板、中密度纖維板(MDF)和定向粒片板(OSB)等四種木質複合板材作爲樑腹材料，探討以不同厚度及組合方向對所組成之木質複合工字樑的靜曲性質之影響。試驗採用長360cm之實大尺寸試材以四點載重靜曲試驗法評估，杉木複合工字樑之跨距與30cm樑深之比值爲11.7。結果顯示，本質複合工字樑之破壞模式主要可分爲樑翼材之水平剪斷破壞（合板）、垂直剪斷破壞、I型破壞、樑腹材之垂直剪斷破壞（粒片板和OSB）及端部挫曲(9mmMDF)等五種，因應力集中之發生，故破壞之位置均發生在剪斷跨距範圍內之樑腹材彼此接處的樑翼開槽接合面。整體而言，在不同樑腹材料之比較上，杉木複合工字樑之靜曲承栽能力以MDF與OSB組合者較優，分別較粒片板與合板複合工字樑高出約24•與39•；在靜曲剛性方面則較粒片板與合板複合工字樑高出約11•與27•。在靜曲撓度之限制下，各組工字樑所能承載之載重值，以在最大靜曲破壞時之載重值的52-61•範圍內之MDF爲最佳，其次依序爲OSB(66-68•)、粒片板(52-77•)與合板(74-77•)，同時，所測得之變位量均未超過在建築技術規範中規定之最大彎麯變位量，且僅爲規定之19-28•。

關鍵字

木質複合工字樑 ； 靜曲承載能力 ； 靜曲剛性 ； 靜曲撓度

並列摘要

The influence of thickness and orientation of various web materials on the flexural properties of composite I-beams fabricated with China fir flanges was investigated in the study. The web materials included plywood, particleboard, medium-density boards(MDF), and oriented-strand board(OSB). Beam specimens were 360 cm long and 30 cm deep, and were tested flexurally based on third-point loading with a span/depth ratio of 11.7. According to the results, the failure mode of I-beam specimens can be classified into 5 major types: horizontal shearing failure of flanges (plywood), vertical shearing failure of flanges, web buckling at end-reaction(9 mm, MDF), I-type failure of flanges, and vertical shearing failure of webs (particleboard and OSB). The failure always occurred along the grooves of the flange at the junctures of the butt joints of the web within the shear span ranges of the I-beams. The static flexural loading capacities of I-beams fabricated with MDF and OSB panels as webs had similar values were 24• and 39•higher than those fabricated with particleboard and plywood panels, respectively, in addition, bending stiffness values were 11• and 27• higher, respectively. Flexural loading capacities under the limitation of the design deflection for I-beams fabricated with MDF panels were between 52• and 61• of the maximum loads at failure, which showed the highest values, followed by I-beams fabricated with OSB webs(66-68•), particleboard(52-77•), and plywood(74-77•). All deflection measurements of China fircomposite I-beams were lower than the limitation specified in the code and ranged between 19•and 28•.

並列關鍵字

wood composite I-beam ； static flexural loading capacity ； bending stiffness ； deflection