火害下直交集成板CLT樓板之炭化深度及撓曲變形行為之研究

Charring Depth and Deflection Behavior of Cross Laminated Timber Floor under Fire

本研究透過進行日本扁柏及北美花旗松此兩種日本及北美常見的材種所製成的CLT樓板，進行1小時火害實驗，並探討其炭化深度及撓曲變形行為。由實驗結果可知日本扁柏CLT樓板之有效炭化速率約為0.77mm/min～0.87mm/min；北美花旗松CLT樓板之有效炭化速率約為0.63mm/min～0.82mm/min。實驗結果與文獻之炭化深度有相近。另外，兩組樓板CLT之炭化深度經量測觀察，分別都可發現在CLT板拼接處有較大的炭化深度產生。由於拼接處無法如同板本身緊密接合，因此會有火源竄入並造成較深的炭化層。樓板的撓曲變形行為方面，本研究亦參考國外規範，進行火害時由於炭化層產生，導致樓板整體勁度下降，以致整體撓度會有持續加大的評估方法進行探討。由評估結果可顯示，當曝火面第1層完全炭化，底層主軸由曝火面第1層集成元的強軸變為曝火面第2層集成元的弱軸，因此造成撓度大幅度的增加。然而，CLT板同層各集成元間並沒有進行側拼膠合，故在燃燒時，集成元間會因為受載重的影響產生縫隙，使得火焰經由縫隙對第3層的強軸集成元進行燃燒，亦可從實驗數據中觀察到此強軸集成元（曝火面第3層）受到火害的影響的行為。

Cross Laminated Timer (CLT) become one of the most popular Engineered wood recently, especially for the midrise and high-rise building. In Taiwan, the fundamental data for design, such as fire design or structural design are not sufficient, more research need to be conducted. In this study, the behavior of CLT under 1 hour burning was carried out, in order to obtain the experimental results for the establishment of Building code in Taiwan.In this study, totally 2 CLT specimens was prepared for the fire testing, including 1 Japanese Cypress CLT floor, and 1 Douglas Fir CLT floor. Charring depth, charring ratio, and residual section are measured after 1 hour fire burning. The testing results indicate that the charring ratios of these specimens are generally higher than the research results from reference, although the difference are limited. It is observed that the residual stiffness is greatly influenced by the strong axis layers of the CLT panel, the deflection is dramatically increased when the first layer disappeared. The testing results give government a fundamental data and reference for further code revision regarding the fire behavior of CLT panels.