Study On The Influence And Optimization Measures Of Frame Structure Characterized By Floor Opening

In order to meet the functions of ventilation,lighting,and use of building structures,more and more shopping mall complexes have opened holes in the middle of structural floors.During the earthquake,due to the partial opening of the floor,the horizontal rigidity of the floor is reduced,and the horizontal force transmission path is changed.Therefore,it is necessary to investigate the seismic performance and optimization measures after the floor is opened.In this paper,based on the engineering example of a specific frame structure project,the model of opening and non-opening of the slab was established on the three kinds of slabs just vacationed,and the analysis of the seismic response of the slab opening to the structure was studied using the ETABS mode decomposition response spectrum method Performance impact.Establish four models with different opening rates and opening positions to explore the effects of opening rates and opening positions on the structure.Then,the thickness of the slab near the opening and the cross-section of the inner,middle and outer frame beams are used to explore the optimization measures after the floor is partially opened.The following conclusions are obtained:The opening of the floor slab will generally reduce the period of the structure,the maximum displacement angle between the floors,and the internal force of the beam and column.Under the assumption of rigid floor slabs,the internal force,period,maximum inter-story displacement angle,and vibration mode participation coefficient of the rotation of the floor slab structure are smaller than those under the elastic floor slab,and the rigid floor slab should be used with caution.The natural vibration period and maximum interstory displacement angle of the structure decrease with the increase of the hole opening rate.This is because the rigid-to-weight ratio of the structural floors increases when the hole is opened.Compared with the asymmetric opening structure,the symmetric opening structure has a smaller displacement coefficient than the vibration mode rotation coefficient around the Z axis,that is,its twist is smaller.Increasing the thickness of the floor slab near the opening has almost no effect on the vibration mode and natural vibration period of the structure and generally increases the internal force of the structural members,which has no effect of optimizing the structure.In general,increasing the cross-sectional size of the frame beam reduces the period of the structure and the displacement angle between the layers.This effect is more obvious when increasing the size of the outer frame beam.Increasing the cross-sectional size of the frame beam at a certain place will cause the internal force of the attachment member of the frame beam to increase and the internal force at a place away from the frame beam to decrease.However,when the cross section of the inner frame column is increased,the axial force at the bottom of the column can be generally reduced,especially for the column of the inner frame column.