- 摘 要
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(1 东南大学土木工程学院, 南京 210096; 2 上海市建筑科学研究院 上海市工程结构安全重点实验室, 上海 200032; 3 东南大学建筑设计研究院有限公司, 南京 210096)
[摘要]一麻五灰是传统木结构中常见的地仗保护做法。通过4组10根采用一麻五灰传统保护处理圆木柱的耐火极限对比试验,研究不同持荷水平、不同直径、是否采用一麻五灰传统保护处理等对圆木柱耐火极限的影响。研究结果表明:对于直径为200mm的圆木柱,当无表面防火处理时,荷载比为30%和50%时耐火极限分别为39-7min和8-7min;当表面采用一麻五灰传统保护处理时,荷载比为30%和50%时耐火极限分别为56-0min和19-9min;对于直径为350mm的圆木柱,当无表面防火处理时,荷载比为30%和50%时耐火极限分别为94-2min和62-5min;当表面采用一麻五灰传统保护处理时,荷载比为30%和50%时耐火极限分别为123-7min和94-7min。可见圆木柱的耐火极限随着持荷水平增加而显著降低,随着直径增加而显著增大;采用一麻五灰传统保护处理后,圆木柱的耐火极限明显增大;一麻五灰传统保护处理能有效降低圆木柱内部的温升梯度,延缓圆木柱开始炭化的时间、降低炭化速度。
[关键词]传统木结构; 圆木柱; 耐火极限; 一麻五灰; 炭化速度
中图分类号:TU372-5, TU366文献标识码:A文章编号:1002-848X(2017)17-0014-06
Experimental study on fire endurance of round timber column with traditional craftwork with one hemp fiber and five plastering application
Wang Zhengchang1, Xu Qingfeng2, Han Chongqing3, Chen Lingzhu2, Hu Xiaofeng1
(1 School of Civil Engineering, Southeast University, Nanjing 210096, China; 2 Shanghai Key Laboratory of Engineering Structure Safety, SRIBS, Shanghai 200032, China; 3 Architects & Engineers Co., Ltd, Southeast University, Nanjing 210096, China)
Abstract:Craftwork with one hemp fiber and five plastering application is one of the most common methods of plaster protection in Chinese traditional timber buildings. Fire endurance comparison tests were conducted on 4 groups of 10 specimens of the round timber columns which were protected by craftwork with one hemp fiber and five plastering application, and the influence of factors such as load level, diameter and craftwork with one hemp fiber and five plastering application were studied on fire endurance of the round timber column. Study results show that for the round timber columns with the diameter of 200mm, if there is no fire protection applied on their surfaces, their fire endurance are 39-7min and 8-7min respectively under the load level of 30% and 50%. If craftwork with one hemp fiber and five plastering application is employed on surfaces, their fire endurance are 56-0min and 199min respectively under the load level of 30% and 50%. For the round timber columns with the diameter of 350mm, if there is no fire protection applied on their surfaces, their fire endurance are 94-2min and 62-5min respectively under the load level of 30% and 50%. If craftwork with one hemp fiber and five plastering application is employed on surfaces, their fire endurance are 123-7min and 94-7min respectively under the load level of 30% and 50%. It shows that the fire endurance of round timber columns decreases greatly with the increasing of load level, and increases remarkably with the increasing of the column diameter. If craftwork with traditional one hemp fiber and five plastering application is employed, fire endurance of round timber column obviously increases. Craftwork with traditional one hemp fiber and five plastering application effectively decreases the temperature gradient inside the round timber columns, delays the beginning time of charring and reduces the charring rate.
Keywords:traditional timber structure; round timber column; fire endurance; craftwork with one hemp fiber and five plastering application; charring rate
*上海市青年科技启明星计划项目(17QB1403400),上海市优秀技术带头人项目(15XD1522600)。
通讯作者:许清风,博士,教授级高工,Email:xuqingfeng73@163.com。