“整数尺”手法在乡土营造中的应用再探——兼论嘉定孔庙大成殿“减尺定侧”方式的可能性

The“Integer-Number Ruler”in Vernacular Architecture—A Study on the“Decrease in Ruler Unit for Section Design”for the Main Hall of the Confucius Temple in Jiading

结合“整数尺”手法的研究背景,通过对上海嘉定孔庙大成殿的勘察及基于三维点云模型的数据分析,探讨其在屋面坡度设计中的“减尺定侧”作法,即从脊桁至檐桁,相邻桁条之间垂直向间距使用逐渐减小的整数尺的方式;进而结合该地区内多个大木单体样本分析此种定侧方式的营造逻辑和使用范围,以此将“整数尺”手法的研究领域由建筑开间、进深和柱高扩展至屋面坡度层面。

Through the study of the“integer-number ruler”and the analysis of survey data based on a 3D point cloud model of the Hall of Great Perfection at the Confucius Temple in Jiading,this paper discusses the possible application of the technique known as“decrease in ruler unit for section design”to the roof slope of the hall.This technique was used to calculate the vertical distance between two roof purlins(from ridge to eaves purlin)in such a way that their magnitudes expressed in whole numbers were gradually decreasing from high to low.The paper then analyzes the construction logic and scope of application of this technique in the region around Jiading in order to extend the“integer-number ruler”study from the building span,building depth,and column height to the roof slope.