Study On The Applicable Height Of Prefabricated Frame Structure

The prefabricated frame structure has many advantages such as green environmental protection,convenient construction and open space,and is widely used in factories,office buildings,residential buildings and other buildings.At this stage,domestic research on prefabricated frame structures mostly focuses on joint connection forms,new material components,etc.There are relatively few studies on applicable height limits;and the country is vigorously developing high-rise buildings,while the existing prefabricated frame structure height It is difficult to alleviate the increasingly tense situation of land resources.Therefore,it is more and more important to study the applicable height of the fabricated frame structure.The applicable height of the fabricated frame structure given in the specification can be further improved under the premise of ensuring the safety and stability of the structure.Taking a 13-story frame structure(with a height of 3.6m)in a 7-degree(0.15g)seismic fortification area as an example,the research is carried out,and ANSYS is used to build models of fabricated and cast-in-place frame structures of different heights,and load ELCENTRO waves,Taft waves,and Nanjing waves.Carry out time history analysis,comprehensively evaluate the feasibility of the structure at various heights through seismic performance indicators,comfort and economy,and draw the following conclusions:(1)When the height is the same,the story displacement angle and maximum lateral displacement of fabricated frame structure in seismic response are greater than those of cast-in-place frame structure.With the increase of height,the two types of frame structures show the characteristics of shear deformation,and the displacement angle and maximum lateral displacement show an increasing trend.The dynamic response results of three seismic waves to frame structures with different heights are different,and Elcentro wave is the most harmful to the structure.(2)When the total number of floors of cast-in-situ frame structure increases from13 to 18,the maximum lateral displacement under large earthquake increases from0.18027 m to 0.33428m;The maximum elastic displacement angle increases from 1/680 to 1/582;The cost proportion of the unit cost of main materials increased from78.6% to 98.4%.Due to the limited cost,it is not suitable to continue to raise the height,so the applicable height of the cast-in-situ frame structure in the area of 7degrees(0.15g)is 18 floors(64.8m).(3)When the total number of floors of fabricated frame structure increases from13 to 18,the maximum lateral displacement increases regularly layer by layer,and the cost proportion of unit cost increases from 87.7% to 98.9%.The maximum elastic displacement angle has increased from 1 / 580 of the 17 th floor to 1 / 489 of the 18 th floor,which has exceeded the deformation requirement of 1 / 550 under frequent earthquakes and is difficult to ensure structural safety.Therefore,the applicable height of the fabricated frame structure in the area of 7 degrees(0.15g)is 17 floors(61.2m).(4)In view of the inapplicability of the fabricated frame structure when the height reaches 18 floors(64.8m),it is proposed to add an X-shaped central support reinforcement structure to improve its stiffness and energy dissipation effect.After adding braces,the deformation of the structure under seismic response is significantly improved,the maximum elastic displacement angle is reduced by 26%,and the maximum lateral displacement is reduced by 51.3%,so that the structure can meet the applicable requirements at this height,indicating that the applicable height of the fabricated frame structure can be further improved by adding energy dissipation braces.