Numerical study on parameter impact on fundamental frequencies and dynamic characteristics of pre-stressed concrete beams

This paper established 6 kinds of different concrete beams, and 5 kinds of models were applied horizontal pre-stress. Their fundamental frequencies and deflections were numerically computed, and the correctness of numerically computational model was experimentally verified. Fundamental frequencies of 6 kinds of models were 46.23 Hz, 68.45 Hz, 69.36 Hz, 70.46 Hz, 72.11 Hz and 157.73 Hz respectively. Concrete beams without being applied pre-stress had a low fundamental frequency. The fundamental frequency of concrete beams could be obviously improved through internally applying pre-stressed tendons to concrete beams. In addition, the improvement effect of Model 5 was more obvious. When pre-stressed tendons were externally applied to the concrete beam, the fundamental frequency was greatly improved. However, externally pre-stressed tendons would limit the use of concrete beams and increase the cost. When other parameters remained unchanged, the fundamental frequency of pre-stressed concrete beams would gradually increase with the increase of pre-stress. When the pre-stress was the same, fundamental frequencies gradually increased with the increase of eccentricity, the number of circular tendons in composite tendons and concrete strength, and gradually decreased with the increase of counterweight. When the applied load was the same, Model 1 was not strengthened and its deflection was the largest. On the contrary, the model which was applied external pre-stress and its deflection was the smallest, but its use was limited and cost was high. In the strengthening proposals of internal pre-stress, composite tendons were applied to Model 5, and it presented a small deflection. When other parameters remained unchanged and the applied load was lower than a value, the deflection of concrete teams gradually increased with the increase of applied load. On the contrary, the deflection of concrete beam tended to be stable with the increase of applied load. When the applied load was the same, the deflection of concrete beams gradually decreased with the increase of eccentricity, the number of circular tendons in composite tendons and concrete strength, and gradually increased with the increase of counterweight.