VIBRATION SERVICEABILITY ANALYSIS OF EXTERNAL-PRESTRESSING CONCRETE FLOOR THROUGH FIELD MEASUREMENTS AND EXPERIMENTS

摘要

In this study,dynamic properties and vibration performance of a very special long-span external-prestressing concrete floor has been analyzed to assess its vibration characteristic and serviceability.We built a structural model with external-prestressing to study its vibration response under different human-induced excitation.Two different types of excitation have been considered in the test and experiment,which are ambient vibration test and pedestrian loads such as single or a group of people walking,stepping,jumping and bouncing.The natural frequencies and damping ratios are identified by the ambient vibration measurement and the root-mean-square(RMS)values of acceleration response are calculated under pedestrian excitation and compared with the acceptable threshold value given in some design codes.The tests indicated that the amplitude value of vibration acceleration response is different under different excitation condition.So it leads to different serviceability results.The RMS value can truly reflect the vibration characteristic of the floor.It is suggested that the natural frequency is not the most important parameter when evaluate the serviceability of concrete floors,but the RMS value of acceleration is.