Using composite yield mechanism to mitigate seismic damage to exposed steel column base connections

This paper presents partial results of a research program under way at Laval University for which the main goal is to introduce the behaviour of steel connections into commercial structural analysis software. The objective of this paper is to derive analytical characterization equations for three commonly used steel column base connections. The procedure to derive these equations is based on a curve standardization theory that requires a number of experimental results in the form of moment–rotation curves that characterize the behaviour of column base connections. Because of a lack of available experimental results, data were obtained from finite element models. The design of a simple steel structure introducing the semi-rigid behaviour of column bases is presented as an example. It shows that consideration of the semi-rigidity of column base connections increases the accuracy of the analysis results and leads to a decrease in structure weight and deformation.Key words: analysis, base, behaviour, column, connection, frame, partial, rigidity, steel, structure.

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Rotational restraint of a simple column base connection

Canadian Journal of Civil Engineering ◽

10.1139/l87-007 ◽

1987 ◽

Vol 14 (1) ◽

pp. 49-57 ◽

Cited By ~ 16

Author(s):

A. Picard ◽

D. Beaulieu ◽

B. Pérusse

Keyword(s):

Base Plate ◽

Relative Displacement ◽

Effective Length ◽

Test Results ◽

Effective Length Factor ◽

Steel Base ◽

Steel Column ◽

Simple Column ◽

Base Connections ◽

Column Base

This paper presents the results of an experimental investigation on the behaviour of steel column base connections. The purpose of the study was to determine the value of the rigidity ratio at the column base (GL). The connection is made of a steel base plate welded to the lower end of the column and attached to the footing by means of two or four anchor bolts. It is generally admitted that this type of connection behaves like a hinge and it is recommended to use GL = 10.0 to evaluate the effective length factor of the column.The test results indicate that for weak-axis buckling a conservative value of the rigidity ratio is GLY = 0.50 and for strong-axis buckling GLX = 1.50, if there is no relative displacement of column ends. The effective length of the column is therefore reduced. A design example shows that the column strength is increased by approximately 30% for slenderness ratios currently met in practice. Key words: steel column, column base connection, moment–rotation curve, buckling.

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Behaviour of a simple column base connection

Canadian Journal of Civil Engineering ◽

10.1139/l85-013 ◽

1985 ◽

Vol 12 (1) ◽

pp. 126-136 ◽

Cited By ~ 25

Author(s):

A. Picard ◽

D. Beaulieu

Keyword(s):

Base Plate ◽

Moment Capacity ◽

Steel Base ◽

Steel Column ◽

Ultimate Moment ◽

Fixity Factor ◽

Simple Column ◽

Concrete Footing ◽

Base Connections ◽

Column Base

This paper presents the results of an experimental investigation on the behaviour of steel column base connections. The connection is effected by means of a steel base plate welded to the lower end of the column and attached to the concrete footing with two or four anchor bolts. The testing program comprised 15 specimens. The measured moment–rotation curves were used to determine the fixity factors of the base connections, taking into account the presence of an axial compression load.The results indicate that the compression force in the column significantly increases the flexural stiffness of the base connection and that the rotational restraint offered by the column base is sufficient to be considered in design. The results also show that the method of analysis used to determine the ultimate moment capacity of the base connection is conservative. Key words: steel column, column base connection, moment–rotation curve, anchor bolt, flexibility factor, fixity factor.

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