Study On Mechanical Properties And Impact Of The Panel Zone Of Beam-to-column Connection In Steel Frames

In the design of steel structure buildings, the joints’ calculation is generally oneof the key work and the difficulties. In most of the steel structure buildings, due to thejoint failure problems appeared firstly which was according to the previous seismicdamage information and survey results, then leading to the failure of the wholestructure. As an important part of the beam-to-column connection, the mechanicalproperties of panel zone play a pivotal role in the whole connection and the overallstructure. There had a different requirement for the design of panel zone in therelevant domestic and foreign standards or provisions. Since its promulgation, China’scurrent standard Technical Specification for Steel Structure of Tall Buildings(JGJ99-98) had been more than ten years, and during this period the standards orprovisions of United States and Japan for the panel zone part had different degrees ofmodification. In order to adapt to the design, construction and application of practicalsituation in our country and keep consistent with the foreign advanced ideas, thedesign requirements about the part of panel zone in the draft amendment for theTechnical Specification for Steel Structure of Tall Buildings (JGJ99-201X) also madecorresponding changes. In view of changes for calculation of bearing capacity aboutthe panel zone in the draft amendment did not given a specific basis of reason.Therefore this thesis traced to the source of the proposal and made the comparativeanalysis of similarities and differences between the proposed formula and the existedcalculation formula in United States, Japan and our country. Based on the combinationwith finite element parameters analysis, discussed the rationality and feasibility of theproposed formula of bearing capacity of panel zone.This thesis firstly made a brief overview of the beam-to-column connection andpanel zone, simply introduced the calculation formula of the bearing capacity for thepanel zone in relevant foreign and domestic provisions or standards. Secondly, on thebasis of analysis on mechanical properties of the panel zone, the proposed formula ofthe panel zone in the draft amendment for the Technical Specification for SteelStructure of Tall Buildings (JGJ99-201X) was deduced. Then the key variableparameters directly related to the capacity of the panel zone (the axial compressionratio, the effective beam depth, the effective column depth, the column web thickness,the column flange thickness and the stiffener thickness) were analyzed by the calculation of finite element model for the joint examples, and made the comparisonbetween the analysis results from finite element model and the theoretical value bythe provisions (or the proposed formula). Finally, this study could concluded that:(1)the proposed formula for the panel zone in the draft amendment for the TechnicalSpecification for Steel Structure of Tall Buildings (JGJ99-201X) is more reasonableand reliable than the calculation formula in China’s current standard TechnicalSpecification for Steel Structure of Tall Buildings (JGJ99-98).(2) the axialcompression ratio, the effective beam depth, the effective column depth and thecolumn web thickness had some effects on the elastic limit bearing capacity of panelzone, but the column flange thickness and the stiffener thickness had nothing with theelastic limit bearing capacity.