| With the diversity of building function requirements,the long-span and large space structures gradually moved into the daily life.On account of the characteristics such as large span,light mass,big flexible,problem of vibration comfort under the human-induced load is more likely to happen to this floor.Because of the special structural arrangement of long-span prestressed girders floor,the reduced height of this structure is less than others.This structure can be very good to solve the building function requirement of long-span and large space.But it has a lower stiffness out of plane and is more sensitive to the vertical vibration,considering the vibration comfort performance reinforcement of existing buildings cost is larger.So in this article,we’re going to think about controlling the comfort level to the design phase,changing the four factors of the structure,such as change the beam height,concrete thickness,increase the concrete floor under the secondary beam and beam spacing.Reaching optimize structure layout plan under vibration comfort.Main work and achievements of the research are presented as below:(1)The entity model of floor is established in the software ANSYS,using the modal superposition method and considering the first six order mode.The relative error of the base frequency and measured value of the obtained structure is-5.5%,and the relative error of peak acceleration and measured value is 8.5%,the simulation results are obtained while in good agreement with the test results.(2)The simulation analysis of the different arrangement of 57 entity models was carried out,based on the correct approach to modeling.The main conclusion as below:1)Modal analysis is obtained by the first six order frequency and vibration pattern of each model.The low-order mode is mainly centered on vertical deformation,and the high-order mode has the horizontal motion of horizontal direction.2)Increase of secondary beam height and increase the concrete floor under the secondary beam,long-span prestressed secondary beam floor structure of fundamental frequency will be increased significantly,and increase the concrete floor under the secondary beam effect is more significant.As the thickness of the concrete slab increases,the base frequency decreases.The change of the spacing of the secondary beams has little effect on the structural base frequency.3)The transient response analysis under the jumping load was carried out by using the modified semi-sinusoidal load model.To obtain the maximum peak acceleration and displacement peak of the different building scheme,the frequency value of the jumping is required according to the frequency division of the structural base frequency.4)By comparing the different floor layout of maximal peak value of acceleration and displacement peak,increase of secondary beam height and increase the concrete floor under the secondary beam,the peak acceleration will be significantly reduced,and increase the concrete floor under the secondary beam effect is more significant.The thickness of the concrete plate increases,the peak acceleration decreases.(3)Increase the height of the secondary beam and increase the concrete floor under the secondary beam can effectively solve the vertical vibration problem of the long-span prestressed girders floor.The concrete usage of the increase the concrete floor under the secondary beam is slightly higher than that of the increasing the secondary beam height,but the quantity of steel is less.(4)And if thinking about the overall cost,considering the vibration comfort of floor structure is the control index,ensuring the floor height.It is possible to consider adding a flat beam floor to optimize the layout scheme of the building,meeting the requirement of the comfort level of the building. |
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