Lipped channel beams (LCBs) are commonly used as flexural members such as floor joists and bearers in the constructionud6 industry. These thin-walled LCBs are subjected to specific buckling and failure modes, one of them being web crippling. Despite considerableud7 research in this area, some recent studies have shown that the current web crippling design rules are unable to predict the test capacities underud8 end-two-flange (ETF) and interior-two-flange (ITF) load conditions. In many instances, web crippling predictions by the available designud9 standards such as AISI S100, AS/NZS 4600 and Eurocode 3 Part 1-3 are inconsistent, i.e., unconservative in some cases, although theyud10 are conservative in other cases. Hence, experimental studies consisting of 36 tests were conducted in this research to assess the web cripplingud11 behavior and capacities of high-strength LCBs under two-flange load cases (ETF and ITF). Experimental results were then compared with theud12 predictions from current design rules. Comparison of the ultimate web crippling capacities from tests showed that the design equations areud13 very unconservative for LCB sections under the ETF load case and are conservative for the ITF load case. Hence, improved equations wereud14 proposed to determine the web crippling capacities of LCBs based on the experimental results from this study. Current design equations doud15 not provide the direct strength method (DSM) provisions for web crippling. Hence, suitable design rules were also developed under the DSMud16 format using the test results and buckling analyses using finite-element analyses.
展开▼
