RESISTANCE FACTOR CALIBRATION FOR PERFORATED COLD-FORMED STEEL COMPRESSION MEMBERS

Federal University Of Ouro Preto Brazil ,Roberta Layra Faragó Jardim,André Luís Riqueira Brandão,Marcilio Sousa Da Rocha Freitas

doi:10.7764/ric.00015.21

Abstract

Cold-formed Steel profiles are structural profiles widely used in civil construction. They are often manufactured with perforations. The designing can be performed using the direct resistance method. Formulations were adapted by Moen and Schafer (2008) to consider the presence of perforations in these profiles. The objective of this study is to investigate the structural safety of columns with web perforations. The calculation of the resistance capacity was performed using the formulations proposed by the authors. The reliability indexes were determined using the First Order Reliability Method (FORM), First Order Second Moment (FOSM) and Monte Carlo Method (MCM), which are reliability methods for the Load and Resistance Factor Design (LRFD) and Limit States Design (LSD) philosophies. Following the same criteria performed by AISI S100, the resistance factors were obtained from the FOSM method. Based on the results, it was found that the desired security level for the LSD philosophy was not achieved. The calculated resistance factors are predominantly lower than the target. However, for the LRFD philosophy, the safety level was achieved, and the resistance factors were higher than the target.

Highlights

Cold-formed Steel (CFS) profiles have less weight and greater width / thickness ratio plates
CFS profiles have commonly been manufactured with perforations along their length, on flanges and webs
Several sections can be manufactured from CFS members, providing advantages for their use

Summary

Introduction

Cold-formed Steel (CFS) profiles have less weight and greater width / thickness ratio plates. For this reason, section instabilities and instabilities along the length of the profiles can occur. Among the existing procedures for dimensioning CFS profiles, the Direct Strength Method (DSM) stands out. This is a method originally developed by Schafer and Pekoz (1998), whose resistance calculation is based on analyses of elastic buckling and stands out for its ease and functionality. The existing demand for profiles with perforations has led to studies by Moen and Schafer (2008), who presented proposals for changes to the original DSM buckling curves

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Conclusion