The Research On Human-induced Vibration And Control Of Cantilever Steel Bar Truss Deck Slab Based On Pedestrian-structure Interaction

With the problem of large span floor vibration becoming more and more serious, the analysis of human induced vibration has been an important content in the structural design stage for the project designer. Therefore, as the main loading form and the cause of floor vibration for the load human induced, the analysis of loading dynamic characteristics and establishing a reasonable and correct loading model should be made. And it is the first condition to carry out large span floor human induced vibration response. But the engineering and technical personnel lacks for deep understanding of the interaction between human and structure, and only according to pedestrian loading model to calculate the induced vibration response is no longer applicable to the low frequency and large span structure. Based on these problems, this paper establishes Fourier series loading models through the experiment, and considering human-structure interaction, made the equivalent of the human body as a biomechanical model with one degree of freedom of mass, stiffness and damping. The biomechanical model and Fourier series loading model are combined to represent a single and moving pedestrian load. Then selecting a twolayer cantilever – steel bar truss deck slab of Gansu Science and Technology Museum as the engineering background, using ANSYS finite element software to simulate the response of the structure under the pedestrian load, the response whether humanstructure interaction considered or not are compared and analyzed. Finally according to the assessment criteria to evaluate the serviceability of the structure, the Tuned Mass Dampers can be adopted to control the vibration of this structure.The main research contents of this paper include the following aspects:(1) Using acceleration sensor to obtain a large number of continuous threedimensional loading time history on the floor, the Fast Fourier Transform is used to analyze it to obtain the Frequency Response Function and to get the distribution and expression with frequency of the parameters of dynamic load factor and the phase angle. The Fourier series load model can be established;(2) When considering the interaction of human and structure, the human body is equivalent to a single degree of freedom model with mass, stiffness and damping. Based on the dynamic equation, the walking frequency, each order of acceleration and load obtained from the former test, three key parameters: mass, stiffness and damping of the biomechanical model can be solved. Finally, according to a large amount of data, regression expression of three parameters can be fit out respectively;(3) A two layer cantilever steel bar truss deck slab of Gansu Science and Technology Museum as the engineering background, a solid model is established through the finite element software ANSYS. Firstly, the modal analysis is carried out to seek for the fundamental frequency of the structure; then considering multiple working condition of loading on the fixed point, single person walking, and crowd synchronization, make a comparison and analysis of acceleration response under the pedestrian load whether considering the human-structure interaction or not;(4) Acceleration response human induced as an assessment criteria of serviceability can be used to evaluate the comfort of the structure. Then make a determination whether to apply the device of vibration control or not. If required, the vibration control effects are compared and analyzed between a single Tuned Mass Damper and 3 degrees of freedom of the damper.