A typical steel frame consists of linear elements in the form of beams, columns, braces and structural joints. The connections of the base of the columns with the supports are the subject of this HERON special issue.
The most common type of column base is that the foot of the column is provided with a welded base plate to be connected to the concrete foundation by some form of anchors. The structural properties of the column bases essentially influence the behaviour of a steel frame under loading. The papers in this HERON issue give details of the behaviour of column bases subject to bending and shear in addition to an axial force in the column. In particular, the resistance and rotational stiffness of the column base are covered.
The papers serve as background information for the rules on column bases in Eurocode 3 "Design of steel structures". The models as described in the papers extend the application of the "component method", initially introduced for beam-to-column joints.
The scope of the papers is limited to unstiffened rectangular base plates for columns focussing on a single I or H section or a rectangular hollow section. However, the methodology is believed to be suitable for extension to a wider variety of designs. The design rules are developed for practical use. As a consequence, a realistic balance is sought between accuracy of prediction on the one hand and quantity of effort involved on the other. It is recognised that the results may be over-conservative in some cases.
Alternative procedures, which are more advanced but more complicated, are available and have been used for the validation of the simplified rules. These procedures are promising for the development of computer software.
The papers are based on the COST C1 report "Column Bases in Steel Building Frames", drafted under the auspices of ECCS Technical Committee 10 "Structural Connections" by an ad hoc-group convened by Frantisek Wald from the Czech Technical University in Prague. The development work has been carried out in parallel with that of WG2 of COST C1.
We herewith wish to thank the editorial board to offer the HERON platform for the dissemination of what is believed a comprehensive "basis" for the design and analysis of steel column bases.
Guest editor: Nol Gresnigt