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Debate: steel shims vs plastic shims for leveling crane rails
I work out of a yard in Nashville and I swear by steel shims under our crawler crane tracks for leveling on uneven ground. But my coworker keeps using these plastic composite shims he found online and says they hold up better. Idk, I feel like plastic squishes under 80 tons of crawler and throws your level off within a week, but maybe it's just me. Has anyone else here tested both and seen a difference in how long the level holds?
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hugow301mo ago
Man that's rough. I've been there with coworkers insisting on something that just feels wrong under load. Your mileage may vary but I've seen plastic shims creep even on lighter equipment than an 80 ton crawler.
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Did you read that report from the crane safety council a couple years back about long term creep testing on plastic shims? They stacked them under a 100 ton test load and measured how much they sank over a month. Plastic shims lost about an eighth of an inch in the first week alone under constant weight. Steel shims barely moved at all. That lines up with what I've seen on job sites. Your coworker might be getting lucky with softer ground that lets the crane settle evenly, but throw a load cycle or some vibration from the boom and that plastic will shift. I wouldn't trust plastic under any crawler over 50 tons, period. You're not crazy to stick with steel.
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