The Study On Effects Of Semi-rigid Connection To Braced Steel Frame Limited Loads

With the broad application of steel structure, more and more problems have beenexposed in steel structural system. All of these problems can be sorted into twocategories: 1) structural design theory problem; 2) joint connection problem. Intraditional design theory, members are related to structure by effective lengths,and connection joints are generally predigested in either fully rigid or ideallypinned without considering the actual M-θcurve of joints. This theory andpredigesting is easy to apply, but have a low precision, and cannot reflect theactual load situation of members.In our country's code for design of structures, structural limited stateincludes two states, limited state for normal use and load capability limited state.Load capability limited state is the lowest criterion in structural design. Inthis paper, we use Fortran90 language to set up a program to analyze limited loadcapability of semi-rigid steel frame based on two-order elastic-plastic analysis(advanced analysis) theory. In the program we consider some adverse factors suchas geometrical imperfection of members, effect of residual stresses etc. and effectof semi-rigid joints, and gradual yielding associated with flexure on the sectionsof members. We use W. F. Chen's three-parameter model to describe the M-θcharacteristic of joints. Furthermore, results demonstrate the validity of themethod presented in the paper through calculation examples and contrast with theresults of Ansys sofeware analysis.Finally, we sum up the classification systems and simulation method ofsemi-rigid joints; we expound advantages and disadvantages of each method, weanalyze the effect of geometrical parameter to top and seat angle connection'sinitial Ki and Mu. We hope this analysis can offer some guides for designer.