Research methods: The analysis method of the strength and rigidity is adopted for reinforcement system and the on-bridge test method is adopted with theoretical calculation and testing train.
Research conclusions : The analyses show the reinforcement system is suitable for jack-in construction of frame bridges with different spans, widths and axial lengths and the tests show the reinforcement system is safe and reliable under condition of train speed limited to 45km/h. This reinforcement system will be safe and reliable for higher speed if some improvements are made，so it is a good way for jack-in construction of bridge of existing line and worth being used widely.
2007, Vol. 24 
