Flexible tied bas is the key structure of arch bridge,which prestress loss has an impor-tant impact on the reliability of bridge,to find out a resonable replacing sechem,this paper relies on a concrete filled steel tube flexible tied arch bridge with span arrangement of 46 m +202 m +46 m as the engineering background,assume 10% prestress loss as the initial state,6 replacement schemes are put forward.By using JC and PNET method,the reliability changes of the bridge is analyzed under each sce-hmes.Results show that scehme 1 and 2 are excutable,scheme 2 can shorten the construction time and ensure the safety,which makes it the final scheme.%柔性系杆作为系杆拱桥的关键构造，其索力损失必然对桥梁的可靠性能造成重要影响，索力损失到一定程度需及时进行更换。依托某跨径跨布置为46 m ＋202 m ＋46 m 柔性系杆飞燕式钢管混凝土拱桥，以系杆索力损失10％为初始状态，提出4种系杆更换方案（单侧同时更换1根、2根、3根、4根，上下游侧同时进行更换），采用一次二阶矩（JC）法及 PNET 法，分析了不同方案下桥梁构件及体系的可靠度变化规律。结果表明：方案1、2均可行，方案1安全但施工步骤多，方案2能够保证桥梁的最低安全等级，同时尽可能缩短施工时间，建议采用方案2。
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