Web crippling strength of cold-formed stainless steel lipped channel-sections with web openings subjected to interior-one-flange loading condition (original) (raw)

This paper reviews the research advancements and design practices related to the structural web crippling response of lipped Cold-Formed (CF) carbon steel, stainless steel, and aluminium channels with web perforations. The web crippling response differs among each material based on the non-linear stress-strain characteristics and degree of strain hardening. Therefore, the reduction in the web crippling strength of web-perforated CF channel sections made of different materials may not be equivalent. The research activities surrounding the web crippling response of CF channels with and without web openings were reviewed initially. Despite the limited design provisions given in the international specifications for the web crippling design of lipped CF channels with web openings, web crippling studies conducted across the world have developed suitable design equations in the form of reduction factors. Past research studies have substantially captured the web crippling response of carbon...

Web holes are commonly used in beams of buildings to facilitate services. In this paper, a combination of tests and nonlinear finite element analyses is used to investigate the effect of such web holes on the web crippling strength of coldformed ferritic stainless steel unlipped channels under the end-two-flange (ETF) loading condition; the case of flanges fastened to the load and reaction plates is considered. The results of 27 web crippling tests are presented, with 9 tests conducted on unlipped channels without web holes and 18 tests conducted on unlipped channels with web holes. In the case of tests with web holes, the holes are located either centred or offset to the load and reaction plates. A quasi-static finite element model is then presented. Good agreement between the tests and finite element analyses is obtained in terms of failure load, failure modes and post-buckling behaviour.

An extensive parametric study of cold-formed ferritic stainless steel unlipped channels with fastened flanges subjected to web crippling under end-two-flange (ETF) loading condition is undertaken, using quasi-static finite element analysis, to investigate the effects of web holes and cross-sections sizes. Both cases of unlipped channels with and without web holes are considered. The web holes are located either centred or offset to the load and reaction plates. It is noted that no cold-formed stainless steel standard provides capacity reduction factors for unlipped channels with fastened flanges subject to end-two-flange loading condition. The strengths obtained from reduction factor equations are first compared to strengths calculated from equations recently proposed for cold-formed stainless steel lipped channels. It is demonstrated that the strength reduction factor equations previously proposed for cold-formed stainless steel lipped channels can be unconservative for cold-formed...

This paper investigates the interior-one-flange web crippling strength of cold-formed steel channels at elevated temperatures. The stress-strain curves of G250 and G450 grade cold-formed steel (CFS) channels at ambient and elevated temperatures were taken from the literature and the temperatures were varied from 20 to 700 °C. A detailed parametric analysis comprising 3474 validated finite element models was undertaken to investigate the effects of web holes and bearing length on the web crippling behavior of these channels at elevated temperatures. From the parametric study results, it was found that the web crippling strength reduction factor is sensitive to the changes of the hole size, hole location, and the bearing length, with the parameters of hole size and hole location having the largest effect on the web crippling reduction factor. However, the web crippling strength reduction factor remains stable when the temperature is changed from 20 to 700 °C. Based on the parametric a...

This paper presents an experimental and numerical investigation into web crippling resistance of unfastened cold formed steel Z-sections subjected to Interior One Flange (IOF). Both Z-sections have stiffened and unstiffened flanges were studied. This paper presented the results of 12 test specimens considering the IOF loading condition. A verified finite element models were developed to simulate the experimental tests. An extended parametric study was carried out based on the verified finite element models. The parametric study included the different factors affecting the web crippling resistance such as; material yield stress, web thickness, inside bend radius, web depth and bearing load length to thickness ratios. The web crippling strength according to the Eurocode EN 1993-1-3 and the North American specification AISI S100-16 were compared to the experimental and the finite element results. The comparisons showed that the two specs; Eurocode EN 1993-1-3 and AISI S100-16 overestim...

The AISI (1996) Specification for the Design of Cold-Formed Steel Structural Members provisions for web-crippling are believed to be conservative for multi-web deck sections. They are based on unfastened specimens and are limited to the use of decks with certain geometric parameters. The unified web crippling equation of the North American (2002) Specification for the Design of Cold-Formed Steel Structural Members (adopted from Canadian S136-94 Specification) is also limited to certain geometric parameters. Although it has new web crippling coefficients for different load cases and different end conditions, in the End One Flange (EOF) loading case, coefficients for the unfastened configuration were used as a conservative solution for the fastened case because there was no directly applicable test data available in the literature.This thesis presents the results of an experimental study on web-crippling strength of multiple-web cold-formed steel deck sections subjected to End One Flange (EOF)loading. Seventy-eight tests were conducted at Virginia Tech. Test specimens lying inside and outside of certain geometric parameters of the specifications were tested with both unrestrained and restrained end conditions. Test specimens lying inside the specification parameters have revealed conservative results in the prediction of web crippling capacity using both AISI (1996) and North American (2002) equations. Using the unified web-crippling equation of North American Specification, a nonlinear regression analysis was performed to update the unfastened case coefficients and derive new fastened case coefficients. Also, the calibration of these coefficients is done for both Canadian S136 (1994) and AISI (1996) specifications.