huangyhg

wire rope
does anyone have any suggestions as to reference material (references, tests, studies, etc) concerning embedment criteria for wire rope. i have been asked to design some precast lifting details using 6x19 class wire rope purple grade. found plenty of information concerning the wire rope but none on embedment criteria. am not quite sure how to figure the amount of embedment required to develope it. the two lifts are estimated at 59,000# and 99,000#. any suggestions are welcome. thanks in advance.
i am no precast expert, but my opinion is that you should not embed the wire rope into the precast, but instead cast a female anchor of some sort into the precast, and thread an eyebolt into this anchor. the wire rope would then be looped through the eyebolt.
daveatkins
agree with daveatkins about not embedding wire rope in concrete. for the loads that you describe, suggest using wire rope sockets for attachment, rather than loops. see info beginning on page 70 of "uss wire rope engineering handbook" - it can be downloaded from my website homepage (link below).
most state dot’s have standard lifting device designs for precast box beams and girders. for precast bridge construction i am use to seeing a par of lifting devices consisting of two or three bundled prestressing strands embedded in the concrete. here are a couple of examples.
jd2, i've got some practical, unpublished information regarding using remnants of prestressing strand in precast panels for lifting. the table was developed in 1972 by the chief engineer of formigli corporation, a well known precast manufacturer by whom i was employed at the time. the load values are based upon testing, tempered by structural analyses.
if you use rope you might exceed the preferred bending radius which i think is about 16:1. as you bend tighter than this you start to effect the capacity of the wire. at 10:1 the wire will start to distort and around 5:1 the wire will use strength.
could i suggest using something like:
thanks to all for your responses/advice/information. personally, i try to utilize engineered connectors (as per ussuri) whenever possible whether it be for wood, concrete, metal stud, etc. in this case, i was specifically requested by the gc to look at wire rope. i used to work for a precast/prestressed manufacturer and, as mentioned by epr, we used pieces of pre-stressed strand as lifting inserts. this was always done as a "we've done it this way for years and have never had any problems with it" and it was in the company engineering manual as a "do it this way" method with no calculations as backup (but many years of "testing"). without any experience with wire rope, i was not sure if the embedment/development requirements would be exactly the same as pre-stressing strand. regardless, after posting the initial request in this thread and doing some research (thank you michst), i notified the gc that i did not have the ability to properly analyze the situation as he requested it and that he would need to modify his request to include other inserts, methods of picking, etc. or he would need to find another engineer with wire rope experience. have not heard back from him in several days so i guess the issue is dead (at least for me). again, i thank everyone for their input.
it's not uncommon in these environs to use 'waste' strand for lifting loops with some precast elements.
epr: is it possible for you to upload your info to sre's website?
sre: ok?
dik
dik,
i'll send it to sre, and he can determine whether he wants to post it on his site.
thanks, epr, it's on my site now (top of the home page)

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