Study On Ultimate Bending Strength Of Rigid Connections Between H-shaped Beam And RHS Column

The seismic design of steel frame requires that the ultimate bending strength ofbeam-to-column connection should be larger than the fully plastic moment of theconnected member. But in the past, it was very difficult to satisfy that as thecalculation of ultimate bending strength only took the flange connection into account.Then people has come to realize the importance to consider the moment capacity ofweb connection. For the rigid connection of H-shaped beam and H-shaped column,the web of beam end can be divided into the bending area and the shear zone asneeded. But when it comes to the rigid connection of H-shaped beam and RHS column,things will become much more complex as there is out-of-plane distortion in thecolumn flange. The calculation of its web connection’s bending strength had become aworldwide knotty problem until some Japanese scholars made a breakthrough in thisarea.Using yield line theory, different Japanese scholars induced three evaluateequations for the bending strength of web connection. This thesis made a review ontheir theoretical derivation at first, then tried to verify them with finite elementanalysis. The results show that the web connection’s bending strength is always lessthan the formulas predict. This can be well explained in plastic limit analysis theory.We all know that the yield line theory is based on upper bound theorem. It can onlygive an upper bound of the true value, which means the minimum one is most likely tobe the true one. By comparison, Eiji Tateyama’s formula gives the most recent value,and it is also very simple for engineering application. As the revise of ‘Technicalspecification for steel structure of tall buildings’ is going on, this thesis suggests thatwe should choose Eiji Tateyama’s formula, rather than choosing Suita Keiichiro’sformula like the Japanese recommendation. With parameter analysis, this thesis alsogived some suggestions for the seismic design of beam-to-column connection.As the Japanese formulas are only provided for the beam-to-column rigidconnections with symmetrical scallop, they don’t suit to our national conditions. Byimitating Eiji Tateyama’s method, we derived the computational formula of webconnection moment for beam-to-column rigid connections with asymmetrical scallop.It is in good agreement with ANSYS results and can be applied in engineering.