故宫太和殿二层斗拱竖向加载试验

为了更好地保护古建筑,采取静力试验方法,以故宫太和殿二层平身科、柱头科、角科斗拱为对象,研究了竖向荷载作用下斗拱的受力性能。基于上述3种斗拱构造特征,制作了1∶2比例模型,进行了竖向加载试验,讨论了不同斗拱在荷载作用下的破坏形式、内力及变形特征,归纳了斗拱的竖向刚度计算模型。结果表明:竖向荷载作用下,太和殿二层斗拱的坐斗及与之相交的头翘、正心瓜拱容易产生破坏,且模型倒置时下层构件受力要小于上层构件。对于不同斗拱而言,斗拱极限承载力:平身科角科柱头科;斗拱变形及残余变形量:柱头科角科平身科;斗拱延性:角科柱头科平身科。竖向荷载作用下,太和殿二层斗拱的竖向刚度计算模型可简化为三折线段形式。     

Structural,Visual, or Iconic: Transmutations of Wooden Brackets in Modern China

Together with pillars and roof, the bracket set is one of the most fundamental structural components of traditional timber-frame architecture in China. Not only structurally indispensable, it was also emblematic of specific building styles developed through history. Entering the modern era, however, its architectural validity was overturned by the use of modern technology and building materials, rendering brackets merely a visual and decorative motif. This paper contends that it was precisely when the bracket set lost its structural significance that it began to be discussed in ways that endowed it with layers of cultural meaning in the context of modern China. Examining its modern appropriations in materials other than wood throughout the twentieth century, the paper explores shifting meanings of brackets in their continuous transmutations from a reminder of a defunct component in the building tradition to a nostalgic sign for an irretrievable architectural past.