Tibetan heritage buildings have a high historical and cultural value. They have endured adverse environmental loadings over hundreds of years without significant damage. However, there are few reports on their structu...Tibetan heritage buildings have a high historical and cultural value. They have endured adverse environmental loadings over hundreds of years without significant damage. However, there are few reports on their structural characteristics under normal environmental loadings and their behavior under dynamic loadings. In this research, a typical Tibetan wooden wall-frame building is selected to study its dynamic characteristics. Field measurements of the structure were conducted under environmental excitation to collect acceleration responses. The stochastic subspace identification （SSI） method was adopted to calculate the structural modal parameters and obtain the out-of-plane vibration characteristics of the slab and frames. The results indicated that the wall-frame structure had a lower out-of-plane stiffness and greater in-plane stiffness due to the presence of stone walls. Due to poor identified damping ratio estimates from the SSI method, a method based on the variance upper bound was proposed to complement the existing variance lower bound method for estimating the modal damping ratio to address the significant damping variability obtained from different points and measurements. The feasibility of the proposed method was illustrated with the measured data from the floor slab of the structure. The variance lower and upper bound methods both provided consistent results compared to those from the traditional SSI method.展开更多
This investigation was conducted to determine the feasibility of using a two-component polyurethane （PUR） adhesive, with special waterproof properties, in constructing wooden structures. We designed and conducted te...This investigation was conducted to determine the feasibility of using a two-component polyurethane （PUR） adhesive, with special waterproof properties, in constructing wooden structures. We designed and conducted tests to compare the shear strength and adhesion performance of PUR with polyvinyl acetate （PVAc） adhesive on block-shear specimens constructed of oriental beech （Fagus orientalis L.）, fir （Abies alba Mill.）, poplar （Populus deltoides Bartr.）, white oak （Quercus alba L.）, sycamore （Platanus orientalis L.） and white walnut （Juglans cinerea L.）. The values of the percentage of wood failure were also determined in specimens constructed with each adhesive. The highest shear strength values of both adhesives were obtained in specimens constructed of beech, while the lowest shear strength values were obtained in fir and poplar specimens. Average shear strength of the PUR adhesive was 16.5% higher than that of the PVAc adhesive. Specimens constructed of fir, poplar and sycamore were characterised by the highest percentages of wood failure, whereas the lowest average percentages of wood failure were obtained in beech and oak specimens. With the exception of oak specimens, there was no statistically significant difference between percentage of wood failure among the PUR and PVAc adhesives. Generally, the PUR adhesive showed an acceptable adhesion performance on wood materials used in our study.展开更多
Today,on the one hand,while the traditional design process continues,on the other hand,digital design systems along with advances in computer technologies continue to present designers with new and effective ideas.Par...Today,on the one hand,while the traditional design process continues,on the other hand,digital design systems along with advances in computer technologies continue to present designers with new and effective ideas.Parametric design is preferred by designers for its relationality,contributing toward versatility,ensuring flexibility,simplifying diversification,and for presenting programmatic solutions.As is seen in a number of areas,we have also begun to encounter the use of parametric designs produced with parametric design systems and wooden materials in urban landscaping.The purpose of this study is to examine the upper cover application and seating elements generated by taking advantage of parametric designs from wooden construction materials in urban landscaping areas,and examine the impact of wooden material characteristics while generating behavior and parametric structures of technologies.After researching parametric design and wooden material concepts,an attempt was made to reach conclusions through analyses conducted by examining parametric wooden designed pavilion and seating element specimens applied in various regions of the world.展开更多
基金National Natural Science Foundation of China under Grant No.51338001Natural Science Foundation of China under Grant Nos.51178028 and 51422801+2 种基金the Fundamental Research Funds for the Central Universities under Grant No.2014YJS087Program for New Century Excellent Talents in University under Grant No.NCET-11-0571111 Project of China under Grant No.B13002
文摘Tibetan heritage buildings have a high historical and cultural value. They have endured adverse environmental loadings over hundreds of years without significant damage. However, there are few reports on their structural characteristics under normal environmental loadings and their behavior under dynamic loadings. In this research, a typical Tibetan wooden wall-frame building is selected to study its dynamic characteristics. Field measurements of the structure were conducted under environmental excitation to collect acceleration responses. The stochastic subspace identification （SSI） method was adopted to calculate the structural modal parameters and obtain the out-of-plane vibration characteristics of the slab and frames. The results indicated that the wall-frame structure had a lower out-of-plane stiffness and greater in-plane stiffness due to the presence of stone walls. Due to poor identified damping ratio estimates from the SSI method, a method based on the variance upper bound was proposed to complement the existing variance lower bound method for estimating the modal damping ratio to address the significant damping variability obtained from different points and measurements. The feasibility of the proposed method was illustrated with the measured data from the floor slab of the structure. The variance lower and upper bound methods both provided consistent results compared to those from the traditional SSI method.
文摘This investigation was conducted to determine the feasibility of using a two-component polyurethane （PUR） adhesive, with special waterproof properties, in constructing wooden structures. We designed and conducted tests to compare the shear strength and adhesion performance of PUR with polyvinyl acetate （PVAc） adhesive on block-shear specimens constructed of oriental beech （Fagus orientalis L.）, fir （Abies alba Mill.）, poplar （Populus deltoides Bartr.）, white oak （Quercus alba L.）, sycamore （Platanus orientalis L.） and white walnut （Juglans cinerea L.）. The values of the percentage of wood failure were also determined in specimens constructed with each adhesive. The highest shear strength values of both adhesives were obtained in specimens constructed of beech, while the lowest shear strength values were obtained in fir and poplar specimens. Average shear strength of the PUR adhesive was 16.5% higher than that of the PVAc adhesive. Specimens constructed of fir, poplar and sycamore were characterised by the highest percentages of wood failure, whereas the lowest average percentages of wood failure were obtained in beech and oak specimens. With the exception of oak specimens, there was no statistically significant difference between percentage of wood failure among the PUR and PVAc adhesives. Generally, the PUR adhesive showed an acceptable adhesion performance on wood materials used in our study.
文摘Today,on the one hand,while the traditional design process continues,on the other hand,digital design systems along with advances in computer technologies continue to present designers with new and effective ideas.Parametric design is preferred by designers for its relationality,contributing toward versatility,ensuring flexibility,simplifying diversification,and for presenting programmatic solutions.As is seen in a number of areas,we have also begun to encounter the use of parametric designs produced with parametric design systems and wooden materials in urban landscaping.The purpose of this study is to examine the upper cover application and seating elements generated by taking advantage of parametric designs from wooden construction materials in urban landscaping areas,and examine the impact of wooden material characteristics while generating behavior and parametric structures of technologies.After researching parametric design and wooden material concepts,an attempt was made to reach conclusions through analyses conducted by examining parametric wooden designed pavilion and seating element specimens applied in various regions of the world.
