Numerical Analysis Of Staggered Steel Bracing-RC Concrete Frame Structure Of Tall Building

Tall buildings is10storeys and over10storeys or height of buildings is greater than28meters in chinese code(Technical specification for concetre structures of tall buildings,2001).Modern tall buildings is widly used because of the development of sociaty and the needs ofpeople living, tall buildings play an important role in the development of the city. Tallbuildings structure and multi-story(single-story) buildings structure should withstand thevertical load and horizontal load, also need to resist earthquakes. However for Single layerbuilding structure, the value of internal forces and displacements produced by horizontaleffect is very small, so it's often negligible; for multi-story structure, the value of internalforces and displacements produced by horizontal effect is gradually increasing; for tallbuildings, horizontal effect is control factor and can't be negligible. Therefore, research on tallbuildings is mainly about structural systems for resisting horizontal effect and method ofstructural analysis and design.The main contents of this paper is: summarizing structural characteristics of the existingseveral common structural systems for resisting lateral force, then propose staggered bracedframe structural system. Considering the mechanical characteristics of this structure,itindicates that this structure system is the most suitable for tall building; while braceundertaked axial tension or pressure, so imagine brace material is steel, so the final form ofthe structural system is staggered steel brace-reinforced concrete frame structure of tallbuildings. In this paper, design comparison groups to do research on the staggered braceframe structure (staggered steel brace-reinforced concrete frame structure of tall buildings)'sdynamic characteristics,seismic performance of elastic, elastoplastic seismic performance.From works based on examples in this paper, draw the following conclusions:(1) Staggered brace frame structure makes the structural stiffness of pin where the bracelocated is grater, the mass of the pin is smaller than the frame shear wall structure.(2) In the case of the same mass, mass distribution has some impacts of vibration of thestructure, the structure that the mass distribution is more uniform will have smaller vibrationcycle. Do elastic response spectrum analysis of5structures shows that: the staggered brace frame structure setting staggered brace, under the effect of two factors which the stiffness ofthe structure is grater and the structural mass is small and uniformly distributed, has a goodseismic performance. The seismic performance is better than brace frame structure, frame,frame shear wall structure, weaker than the staggered shear wall structure.(3) Deformation curve of the staggered brace frame structure under earthquake is theflexure-shear style, between each floor there is wave-shaped deformation characteristics, thelower floors has a large fluctuations, the upper floors has a small fluctuations, weak layer isthe lower part of the building. Do PUSHOVER plastic calculations on3structures which arethe frame structure, brace frame structure, staggered brace frame structure. From analysis ofthe structural ultimate displacement of monitoring points, the ductility of the staggered braceframe structure is poorer than the frame structure, better than the brace frame structure, theductility is between the two structures system. Staggered brace frame structure has a higherultimate seismic bearing capacity of plastic than the frame structure, the brace frame structure.(4) In process of PUSHOVER plastic calculation, plastic hinge of the staggered braceframe struture located in the beams, columns, braces, the plastic hinge in beams is many, theplastic hinge in columns and beam is few. The plastic hinge appears in the brace of thestaggered brace frame struture,but the plastic hinge does not appears in the brace of the braceframe struture, indicating that the brace of the staggered brace frame struture can better playit's role in energy consumption than the brace frame structure. The plastic hinge of staggeredbrace frame structure mainly concentrated in the lower part of the building, the bottom of thecolumn is in the most unfavorable stress state, in the design process,we can enhance the localcolumn for better seismic performance.