关键词: CRTSⅡ型板, 简支梁, 无砟轨道, 动力响应, 自振频率

Abstract:

In order to explore the dynamic performances of continuous CRTSⅡ ballastless track slab-bridge system,a multi-point measuring system was established.With the help of this system,the dynamic response of each component of the system was observed in detail,and the lateral acceleration,vertical acceleration and vertical displacement of the CRTSⅡ track slab system,as well as the natural vibration frequency,damping ratio and impact coefficient of the beam,were analyzed statistically.The results show that ( 1) CRTSⅡ track slab system has a good capability of buffering train-induced vibrations,with a total vibration reduction rate of more than 90%,a maximum vertical acceleration of bridge deck of 3. 93m/s2 and a maximum vertical displacement of 0. 131 4 mm after the vibration has been transferred to the bridge deck,which meets the requirements of the related standards; ( 2) the train load-induced vibration has a slight effect on the adjacent railway,which focuses on the fixed support side; ( 3) the train load-induced vibration is primarily positively related to the train speed,and parts of the structure may vibrate differently from the track slab-bridge system at a special train speed,which may lead to cracks or damage; and ( 4) the measured one-order natural vibration frequency of simply-supported beam in the CRTSⅡ track slab-bridge system is about 7. 27Hz,which is slightly greater than the theoretical one of the simply-supported beam without track slab.

Key words: CRTSⅡ slab, simply-supported beam, ballastless track, dynamic response, natural vibration frequency