Study On Dynamic Characteristics And Vibration Serviceability Of A Large-span Steel Space Frame-glass Composite Floor

At this stage,vibration serviceability of the large-span flexible floor has gradually become a hot issue in the field of engineering research.Compared with the ordinary large-span floor slab structure,recently the structural system of large-span steel space frame-glass composite floor of the big sites archaistic construction and scenic pedestrian overpass is more flexible and complex,its dynamic characteristics and vibration mechanism are uncertain,and this kind of floor slab is lacking at home and abroad research.Based on Ming-tang site of Luoyang Sui-Tang paradise,this paper has researched the dynamic characteristics and vibration serviceability under human walking of the large-span steel space frame-glass composite floor of Ming-tang.Main research: a refined finite element model based on serviceability evaluation was established by considering the factors of load value,floor structure and architectural surface.The dynamic characteristics parameters were obtained by eigenvalue analysis,and compared with the result(frequency and vibration mode)of field test.Analyzing the dynamic response of the floor with various load conditions and different damping ratios by MIDAS/Gen.At the same time,the field test about vibration serviceability of the floor was carried out.Vibration mechanism of the large-span steel space frame-glass composite floor was obtained,and the vibration serviceability was evaluated.Research shows that: the finite element model who considering the factors of load value,floor structure and architectural surface,can reflect the dynamic characteristics of the actual structure well.The damping ratio of the floor is 2.78% ~ 2.98%,and the damping ratio will increase because of a number of rubber connecting product were used in the floor construction.The most unfavorable vibration position of the open holed,cantilevered and hanging floor commonly adopted in ruins protection buildings locates in the floor.Typical coupled vibrations between various floors can be observed in the floor,this characteristics should be considered carefully in the evaluation of vibration serviceability.The vibration serviceability of the large-span steel space frame-glass composite floor meet the design requirements under walking load that crowd density is 0.8 person per square meters.