Abstract: The reinforced concrete and pre-stressed concrete truss arch bridges were 1argely built in China，otherwise truss stone arch bridge was rarely constructed．The inherent causes have been discussed for Tianchi Bridge which is atruss stone bridge．The method of adding to reinforced concrete arch with 3-fibs to reinforce and strength the orginal arch bridge was put forward according to approximate formula about one order self-vibration frequency．To ensure the excellent link with the two arch interfaces。the method with firstly remove pavement then recon struct it was adopted．The capacity standard was impmved from truck-10 to truck-20．The static and dynamic calculation for before and after reinforce have been performed by Nastxan．The results show the self-vibration frequency was effectively improved and the capacity was achieved．At last．the construction key was given．

Key words: Truss 8tone arch bridge, Tianchi Bridge, Disease analyze, reinforce design, Static and dynamic calculation

摘要： 钢筋砼及预应力砼桁式拱桥在国内建造较多，而桁式石拱桥很少见．文中分析桁式石拱桥一天池大桥振感明 显的内在原因，根据拱桥一阶自振频率近似计算公式，采取加设三条钢筋砼拱肋加固改造方案，通过调整桥面系加 载顺序确保新旧拱圈之间有良好结合，并将原设计标准由汽一lO提高到汽一2o，应用rqastran程序对加固前后进行 静、动力分析．结果表明，加固后该桥的自振频率显著提高，满足承载力要求，达到了加固改造的目的，文中最后给 出了施工要点．

关键词: 桁式石拱桥, 天池大桥, 病害分析, 加固设计, 静动力计算