MOMENT-ROTATION FOR BASE CONNECTION WITH DIFFERENT DETAIL CONFIGURATIONS

Abstract

This research has attempted to indicate and to distinguish the difference between the variety of fixed steel base details. The aim of this study has been carried out to produce information in an easily presentable form to aid designers in their understanding of choosing between the wide range of common fixed steel base details. In this research, finite element technique for both linear and nonlinear analyses of base connections has been integrated with the problems of fixed base detail configurations using ANSYS-program. The analyses is conducted to investigate both of the base plate and the type of detail. configuration and then, the global frame analyses is investigated. In case of linear analysis of the base plate, the base plate is divided into a number of shell elements with six-degrees of freedom. The underneath concrete base has been idealized in the form of uncorrelated gap elements (as compression member only). The attached anchor bolts are treated as elastic springs that sustain tensile, compression and shear resistance. In case of nonlinear analysis, SOLID45 element type is used for base plate, anchor bolts, stiffener plates and the attached part of the column. The concrete base is chosen as gap elements (LINK I 0). However, the analysis is focused on the influence of base detail configurations, including attachment size and stiffeners arrangement and their height, upon the design aspects of the base plate and the global frame analysis. In this respect, the buckling length and lateral displacement of multi-story and multi-bay frames have been also investigated. The results of the present analysis have been verified by means of comparisons with other researches. Empirical formulas to calculate the moment-rotation relationship for different base detail configurations have been proposed. These formulas are accurate and rather simple for daily applications use.