Liang Cao

In this paper, an analytical model representing the human-structure interaction (HSI) system of steel-concrete composite floors under human vibrations is described and discussed. In the theoretical analysis, the human and composite floor are idealized as the subsystems represented by a linear oscillator model and the anisotropic rectangular plate, respectively. The analytical formula for the natural frequency and acceleration response of a steel-concrete composite floor with various boundary conditions and HSI is proposed. For analyzing the natural frequencies, the human subsystem can be treated as a structural system with added mass, damping, and stiffness. The proposed analytical solution on the acceleration response is based on the combined weighted residual and perturbation method, which is simple to be implemented and can avoid the cumbersome numerical calculations. The theoretical solutions are validated with the experimental results. A sensitivity study utilizing the analytical solution was also conducted to investigate the effects of walking frequency, occupant weight, sprung mass, equivalent damping ratio, occupant natural frequency, and occupant spacing on the natural frequency and peak acceleration.

An accurate determination on the acceleration response of a long-span and lightweight steel-concrete composite floor is essential for assessing the floor’s human-induced vibration serviceability, in which the interaction between human and structure should be considered. In the theoretical analysis, the human and floor subsystem are idealized as the linear oscillator model and anisotropic rectangular plate, respectively. This paper presents an analytical approach to determine the acceleration response induced by the walking activity on a steel-concrete composite floor with two opposite edges simply supported and the other two edges clamped. The proposed approach is based on the combined weighted residual and perturbation method. Implementation of this method is simple and avoids cumbersome mathematical calculations. The theoretical solution is validated with experimental results. A sensitivity study using the analytical solution was also conducted to investigate the effects of walking path, damping ratio, and walking frequency on the peak acceleration.

The current trend toward longer spans and lighter floor systems, combined with reduced damping and new activities, have resulted in an increasing complaints on floor vibration from building owners and occupants. Heel-drop, jumping, and walking impacts, which may lead to discomfort problems in daily life, were imposed on a large-span arched prestressed concrete truss (APT) girder system studied. The natural frequencies, peak acceleration, average root-mean-square acceleration (ARMS), maximum transient vibration value (MTVV), and perception factor for the girder were obtained and checked against the existing codes and standards. The purpose of this paper is to provide researchers and engineers with a detailed evaluation on the vibration behavior of the APT girder under different human activities, with a comprehensive review on the relevant criteria and some suggestions. Lastly, the following threshold peak accelerations are suggested: 650[ ]mm/s²for transient heel-drop impact, 1450[ ]mm/s²for transient jumping impact, and 250[ ]mm/s²for steady-state walking. In addition, the threshold values of 90[ ]mm/s²and 50[ ]mm/s²are suggested for MTVV and ARMS, respectively, under steady-state walking.

An extensive experimental and numerical research was undertaken to study the vibration serviceability of a long-span fanshaped prestressed concrete floor system to be used in the lounge of a major airport. Specifically heel-drop and jumping impact tests were conducted to obtain the natural frequencies and modal damping ratios of the floor system, followed by the discussion on the distribution of peak accelerations. Running tests and simulation were also performed to capture the acceleration responses. Moreover, the finite element method was used to evaluate the dynamic characteristics. The floor system is found to have a low fundamental frequency (≈6.00 Hz) and the corresponding modal damping ratio (average ≈2.20%). The comparison of the experimental results with the published American institute of steel construction (AISC) design guide indicates that the prestressed concrete floor system exhibits satisfactory vibration perceptibility overall. The study results also show that the intensity and the location of impact excitation have a significant influence on the rate of acceleration decay. A crest factor β_rp is proposed based on the test results to calculate the maximum root mean square acceleration for running for convenience.