金屬複合木質桁架樑之靜曲性質研究

本研究以省產杉木及金屬管組合成平行弦桿複合軒架樑作為樓板托樑之應用，並以四點載重進行靜曲試驗，探討金屬管組合角度、管徑大小、杉木弦桿按合方式等因子對靜曲性質之影響。實大尺寸之複合析架樑其樑高為35cm，長312.5～336cm，結果顯示複合析架樑之破壞主要是在構材接合位置。樑腹金屬管以52.5°及60°角度組合之條件，其彎曲力矩分別較的45°組合者高出44.3%及32.4%。在剪力跨距範圍內之樑腹桿材所承載之軸向拉伸或壓縮力亦分別較45°組合者高出25.6%及12.6%。金屬管徑1.0cm及1.2cm之組合樑對彎曲力矩的影響不顯著。在靜曲剛性方面，以52.5°及60°角度組合之複合析架樑平均較45°者高出34.1%及42.1%，同時當上下弦桿材以雙支對剖材組合時，金屬管徑1.0cm組合樑之靜曲剛性較管徑1.2cm者高40.2%，然弦桿材以單支杉木材組合時，有相反之趨勢。

關鍵字

杉木；桁架樑；靜曲性質；托樑

並列摘要

The parallel chord composite trussed beams fabricated with China fir lumber and steel tubes were evaluated with static four-point bending test to identify the effects of orientation and diameter of web chord members and assembly configuration of top and bottom chord members on the static bending performance in the application of floor joints. Structural sizes of composite trussed beams were 312.5 to 336cm in length and 35cm in depth. The major failures were mostly occurred at the joints located between supports and loading heads. The maximum bending moment at failure for the beams with the steel tubes in 52.5° and 60° orientation at web were 44.3% and 32.4% respectively higher than that of 45° orientation. Similarly in static bending stiffness, there were 34.1% and 42.1% respectively, higher than that of 45° orientation. The axial tension or compression of web chords within the ranges of shear span for the beams with web chord in 52.5° and 60° orientation were 25.6% and 12.6% respectively, higher than that of 45° orientation. Insignificant difference in the results of maximum bending moment at failure was found between the beams assembled with the steel tubes both 1.0cm and 1.2cm in diameter. The static bending stiffness for the beams assembled with double chords on the top and bottom sides and 1.0cm steel tubes at the web was 40.2% higher than that of 1.2cm steel tubes, while the opposite trend was noticed for the beams assembled with single chord on the top and bottom sides.

並列關鍵字

China fir Trussed beam ； Static bending properties ； Joist

國際替代計量

金屬複合木質桁架樑之靜曲性質研究

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