旧面板对轻型木结构钉节点力学性能的影响
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摘要
旨在通过新、旧定向刨花板(OSB)面板钉节点的对比研究,探究面板自然劣化对钉节点连接性能的影响,为今后的木结构设计和用材作参考。选取云杉-松木-冷杉规格材(SPF)、不同厚度的新旧OSB和国产麻花钉,将麻花钉垂直钉入OSB和SPF之间,依据荷载垂直于木材纹理和平行于木材纹理两种方向,共制作72个钉节点连接试件。试验参考ASTM D1761-12,对试件进行单调加载,研究不同厚度自然劣化后的旧OSB面板在横纹和顺纹连接情况下对轻型木结构钉节点力学性能的影响。结果表明:新旧OSB连接对比,除延性系数外,旧OSB面板与SPF连接的钉节点试件的荷载、刚度、耗能能力等都呈下降趋势;厚度不同的OSB连接对比,12. 0mm厚度的OSB面板连接的钉节点的荷载、刚度、延性系数、耗能能力都大于9.5 mm的OSB面板连接的试件,且12.0 mm旧板连接的力学性能下降幅度小于9.5 mm;在荷载、初始刚度、延性方面,旧板横纹连接小于顺纹连接的下降幅度;在耗能上,旧板横纹连接与顺纹连接区别不明显。试验中多发生钉子一铰弯曲和OSB、SPF破坏的试验现象,符合欧洲木结构设计规范中的破坏模式,因此可用欧洲规范计算本研究中钉连接节点最大荷载。
Light wood frame structure consists of wood frame shear wall,floor and roof system. As a main bearing system,the wall can not only withstand vertical loads and transmit the loads to the foundation,but also resist the horizontal effects caused by earthquakes or wind. The shear wall is mainly connected by nails. The performance of nailed joints directly affects the lateral stiffness and horizontal bearing capacity. Current studies focus on the influence of the panel type,thickness and the contact area on the mechanical properties of the nailed joints,in which,all the panels used were newmaterials and no study discussed the effects of old OSB(oriented strand board) on the mechanical property of nailed joints. By comparing the newand old OSB connected to the SPF lumber,this paper aimed at investigating the changing rules of the mechanical performance of nailed joints due to the natural aging OSB panels and then made reference to the design and material selection. The old OSB involved in the research was removed from existed buildings after 6 years' service. Seventy-two nailed joints specimens were made with SPF lumber,the newand old OSB and the domestic twist nails. The nails were driven vertically between the OSB and the SPF lumber according to the directions of perpendicularto-grain and parallel-to-grain. Monotonic loading test was applied based on ASTMD1761-12 to explore the influence of the newand old OSB panels with different thicknesses using the perpendicular-to-grain connection and parallel-to-grain connection on the mechanical properties. Test results showed that,when comparing old and newOSB connections,the load-withstanding,stiffness,and energy dissipation capacity of the nailed joints specimens connected with old OSB had a decreased trend except the ductility factor. The decrease of all mechanical properties for 12.0 mm thick old OSB was smaller than that of the 9.5 mm thick OSB. In the comparison of different thicknesses of OSB,the nailed joints specimens connected with 12.0 mm thick OSB showed better load-withstanding,stiffness,ductility coefficient,energy dissipation capacity than that of the 9.5 mm thick OSB. For the load-withstanding,stiffness,ductility factor,the decrease of perpendicular-to-grain connection of the old OSB was smaller than the parallel-to-grain connection. For the energy dissipation capacity,there was no obvious difference between the parallel-to-grain connection and the perpendicular-to-grain.The fracture modes of nailed joints were typically the OSB and SPF lumber cracking and rods bending,which consisted of the destructive pattern in the European Wood Design Code. The maximum load of the nailed joints can be calculated by the European Wood Design Code. The theoretical calculated values were in good agreement with the experimental values.The maximum load fitting results of the 9.5 mm thick newOSB board connected to the SPF lumber were better than that of the 12.0 mm thick OSB.
Light wood frame structure consists of wood frame shear wall,floor and roof system. As a main bearing system,the wall can not only withstand vertical loads and transmit the loads to the foundation,but also resist the horizontal effects caused by earthquakes or wind. The shear wall is mainly connected by nails. The performance of nailed joints directly affects the lateral stiffness and horizontal bearing capacity. Current studies focus on the influence of the panel type,thickness and the contact area on the mechanical properties of the nailed joints,in which,all the panels used were newmaterials and no study discussed the effects of old OSB(oriented strand board) on the mechanical property of nailed joints. By comparing the newand old OSB connected to the SPF lumber,this paper aimed at investigating the changing rules of the mechanical performance of nailed joints due to the natural aging OSB panels and then made reference to the design and material selection. The old OSB involved in the research was removed from existed buildings after 6 years' service. Seventy-two nailed joints specimens were made with SPF lumber,the newand old OSB and the domestic twist nails. The nails were driven vertically between the OSB and the SPF lumber according to the directions of perpendicularto-grain and parallel-to-grain. Monotonic loading test was applied based on ASTMD1761-12 to explore the influence of the newand old OSB panels with different thicknesses using the perpendicular-to-grain connection and parallel-to-grain connection on the mechanical properties. Test results showed that,when comparing old and newOSB connections,the load-withstanding,stiffness,and energy dissipation capacity of the nailed joints specimens connected with old OSB had a decreased trend except the ductility factor. The decrease of all mechanical properties for 12.0 mm thick old OSB was smaller than that of the 9.5 mm thick OSB. In the comparison of different thicknesses of OSB,the nailed joints specimens connected with 12.0 mm thick OSB showed better load-withstanding,stiffness,ductility coefficient,energy dissipation capacity than that of the 9.5 mm thick OSB. For the load-withstanding,stiffness,ductility factor,the decrease of perpendicular-to-grain connection of the old OSB was smaller than the parallel-to-grain connection. For the energy dissipation capacity,there was no obvious difference between the parallel-to-grain connection and the perpendicular-to-grain.The fracture modes of nailed joints were typically the OSB and SPF lumber cracking and rods bending,which consisted of the destructive pattern in the European Wood Design Code. The maximum load of the nailed joints can be calculated by the European Wood Design Code. The theoretical calculated values were in good agreement with the experimental values.The maximum load fitting results of the 9.5 mm thick newOSB board connected to the SPF lumber were better than that of the 12.0 mm thick OSB.
引文
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[7]SAWATA K,SHIBUSAWA T,OHASHI K,et al. Effects of density profile of MDF on stiffness and strength of nailed joints[J].Journal of Wood Science,2008,54(1):45-53.
[8]熊海贝,潘志付,康加华,等.轻型木结构面板钉节点单调加载试验研究[J].结构工程师,2011,27(6):106-112.XIONG H B,PAN Z F,KANG J H,et al. Test study on behavior of stud-to-sheathing nail joints under monotonic load in light wood frame constructions[J]. Structural Engineers,2011,27(6):106-112.
[9]邹晓静,郭云,刘雁.轻型木结构中钉节点试验研究[J].建筑结构,2010,40(3):111-114.ZOU X J,GUO Y,LIU Y. Test research on nail joints of light wood structure[J]. Building Structure,2010,40(3):111-114.
[10]日本住宅&木材技術センタ一:木造軸組工法住宅の限界耐力計算にょる設計の手引き東京[M].東京:株式會社研恒社,2002.Japan 2x4 Home Builders Association. Structural design guidelines for wood frame construction[M]. Tokyo:Japan 2x4Home Builders Association,2002.
[11]陈松来,陈志勇,樊承谋,等.木结构剪力墙中钉连接的实验研究[J].中山大学学报(自然科学版),2008(4):133-138.CHEN S L,CHEN Z Y,FAN C M,et al. Experimental study on nailed joints in shear wall of wood structure[J]. Acta Scientiarum Naturalium Universitatis Sunyatseni,2008(4):133-138.
[12]祝恩淳,陈志勇,潘景龙.覆面板钉连接的承载性能试验研究[J].同济大学学报(自然科学版),2011,39(9):1280-1285.ZHU E C,CHEN Z Y,PAN J L. Experimental study of behavior of panel-to-lumber nail connections in light wood frame construction[J]. Journal of Tongji University(Natural Science),2011,39(9):1280-1285.
[13]European Committee for Standardization. EN 1995-1-1(Eurocode5)Design of timber structures-parts 1.1:general rules and rules for buildings[S]. Brussels:European Committee for Standardization,2006.
[2]高建,董文文,黄素涌,等.木结构中钉节点性能影响因素的研究进展[J].林产工业,2016,43(4):7-11.GAO J,DONG W W,HUANG S Y,et al. Research progress for influencing factor of nail joint properties in wood structure[J].China Forest Products Industry,2016,43(4):7-11.
[3]董伟博,高颖,于志明,等.轻型木结构夹板剪力墙钉连接节点试验研究[J].建筑结构,2015,45(6):54-57.DONG W B,GAO Y,YU Z M,et al. Experimental research on MIDPLY shear wall nail joints of light wood structures[J].Building Structure,2015,45(6):54-57.
[4]杜敏,费本华,谢宝元,等.轻型木结构中钉节点试验研究[J].建筑结构,2012,42(7):142-145.DU M,FEI B H,XIE B Y,et al. Test research on nail joints of light wood structure[J]. Building Structure,2012,42(7):142-145.
[5]阙泽利,杨玲,赵丹,等.不同覆面条件下木结构剪力墙钉节点性能研究[J].建筑结构,2014,44(9):93-96.QUE Z L,YANG L,ZHAO D,et al. Experimental study of nail joints of shear walls under different cladding conditions in wood frame structures[J]. Building Structure,2014,44(9):93-96.
[6]王昕明,肖忠平,张苏俊.速生杨木LVL与胶合板钉连接节点受力性能[J].林业科技开发,2015,29(6):85-90.WANG X M,XIAO Z P,ZHANG S J. Mechanical performance of nail-fastened nodes of fast-growing poplar laminated veneer lumber and plywood[J]. Journal of Forestry Engineering,2015,29(6):85-90.
[7]SAWATA K,SHIBUSAWA T,OHASHI K,et al. Effects of density profile of MDF on stiffness and strength of nailed joints[J].Journal of Wood Science,2008,54(1):45-53.
[8]熊海贝,潘志付,康加华,等.轻型木结构面板钉节点单调加载试验研究[J].结构工程师,2011,27(6):106-112.XIONG H B,PAN Z F,KANG J H,et al. Test study on behavior of stud-to-sheathing nail joints under monotonic load in light wood frame constructions[J]. Structural Engineers,2011,27(6):106-112.
[9]邹晓静,郭云,刘雁.轻型木结构中钉节点试验研究[J].建筑结构,2010,40(3):111-114.ZOU X J,GUO Y,LIU Y. Test research on nail joints of light wood structure[J]. Building Structure,2010,40(3):111-114.
[10]日本住宅&木材技術センタ一:木造軸組工法住宅の限界耐力計算にょる設計の手引き東京[M].東京:株式會社研恒社,2002.Japan 2x4 Home Builders Association. Structural design guidelines for wood frame construction[M]. Tokyo:Japan 2x4Home Builders Association,2002.
[11]陈松来,陈志勇,樊承谋,等.木结构剪力墙中钉连接的实验研究[J].中山大学学报(自然科学版),2008(4):133-138.CHEN S L,CHEN Z Y,FAN C M,et al. Experimental study on nailed joints in shear wall of wood structure[J]. Acta Scientiarum Naturalium Universitatis Sunyatseni,2008(4):133-138.
[12]祝恩淳,陈志勇,潘景龙.覆面板钉连接的承载性能试验研究[J].同济大学学报(自然科学版),2011,39(9):1280-1285.ZHU E C,CHEN Z Y,PAN J L. Experimental study of behavior of panel-to-lumber nail connections in light wood frame construction[J]. Journal of Tongji University(Natural Science),2011,39(9):1280-1285.
[13]European Committee for Standardization. EN 1995-1-1(Eurocode5)Design of timber structures-parts 1.1:general rules and rules for buildings[S]. Brussels:European Committee for Standardization,2006.