单檐歇山式木构古建抵抗强震试验调查

为更好地保护我国古建筑，以单檐歇山式木构古建筑为例，采用振动台试验方法，研究了强震作用下我国明清官式木构古建的抗震性能。根据清工部《工程做法则例》的相关规定，参照故宫某单檐歇山式木构古建构造特征，制作了一个十等材古建筑试验模型。该模型包括平摆浮搁柱底、榫卯连接、斗拱、梁架、瓦顶、墙体等构造。通过对模型输入烈度逐渐增强的1940年El-centro波，并考虑地震波为水平双向作用，分析强震作用下不同构造的试验现象，开展详细的震后调查，获得不同构造在强震作用下的抗震性能和震害机制。结果表明：强震作用下，我国明清官式木构古建的振动形式表现为柱架、斗拱、梁架及屋顶的近似同步往复摇摆；主要震害包括柱底偏移、榫卯节点开裂及拔榫、斗拱偏移及错位、额枋-垫板分离、墙体倒塌等，但承重木构架受损不严重，结构未产生倒塌。其良好抗震性能的原因与古建筑的构造特征密切相关。

Experimental investigation of seismic performance of single layer gable and hip roof type of Chinese ancient building under high intensity earthquake

To effectively protect Chinese ancient building, its single layer gable and hip roof type is taken as example, the seismic performances under high intensity earthquakes are studied by shaking table tests. According to rules of Building Codes in QING dynasty, referring constitutions of a single layer gable and hip roof type building in the Forbidden City, a model of Chinese ancient 10th level standard is built. The model includes free-standing column root, tenon-mortise connection between beams and columns, tou-kung (bracket sets), beam system, tile roof, filler walls and so on. Then the 1940 El-centro earthquake waves in horizontal directions are applied to the model, the intensity are gradually increased to very high level. Experimental phenomena of different constitutions of the model and analyzed, the damage symptoms are also investigated in detail. Results show that under high intensity earthquakes, the column structure, the tou-kung, the beam system and the roof vibrate as synchronous motion of slow sway. Main damage symptoms of the structure include column root deviates from its origin position, tenon pulled out of mortise, cracks appear on tenon-mortise joints, part of tou-kung components deviate from their origin positions, disconnection between the tie beam and its cushion board, collapse of filler walls and so on. However the damages are not serious, nor does the timber structure collapse. The seismic performances of Chinese ancient building under high intensity earthquakes relate closely to its constitution characteristics.