LearningAlways
Structural
Hello,
I have a question regarding precast/tilt panel erection lifters and their tension failure mechanism.
Lifting tables showing anchor capacities are provided by anchor suppliers, capacities are either maximum mechanical capacity of the lifter (yielding of the lifters itself?) or a capacity that I'm assuming is limited by the concrete (e.g. concrete breakout). 9 times out of 10, the way to get the maximum capacity out of a lifter is to add lifter bars, typically #6 bent bars will do the job.
I've assumed for years that the failure mechanism of the 'concrete' portion of the lifter is tension bar yielding when a lifting device has lifting bars...adding a tension bar typically increases the capacity to the mechanical capacity of the lifter. I'm questioning that assumption.
Is it safe to assume in ALL cases that rebar will yield before a breakout cone is formed? Or in MOST cases? To that end, does embedded rebar form a cone that we need to worry about? I've never seen someone check that failure mechanism in a lifter or in any connection with embedded rebar... typically the check on embedded rebar is tension only and making sure the bar is developed properly, nothing to do with breakout.
Thank you.
I have a question regarding precast/tilt panel erection lifters and their tension failure mechanism.
Lifting tables showing anchor capacities are provided by anchor suppliers, capacities are either maximum mechanical capacity of the lifter (yielding of the lifters itself?) or a capacity that I'm assuming is limited by the concrete (e.g. concrete breakout). 9 times out of 10, the way to get the maximum capacity out of a lifter is to add lifter bars, typically #6 bent bars will do the job.
I've assumed for years that the failure mechanism of the 'concrete' portion of the lifter is tension bar yielding when a lifting device has lifting bars...adding a tension bar typically increases the capacity to the mechanical capacity of the lifter. I'm questioning that assumption.
Is it safe to assume in ALL cases that rebar will yield before a breakout cone is formed? Or in MOST cases? To that end, does embedded rebar form a cone that we need to worry about? I've never seen someone check that failure mechanism in a lifter or in any connection with embedded rebar... typically the check on embedded rebar is tension only and making sure the bar is developed properly, nothing to do with breakout.
Thank you.