Anchor Bolts for Ship Lift Rails

[farhanjnawab]

Dear All,

We are supposed to rip-off concrete foundation slab 300mm thk holding ship lift 132 lb/yd rails through U type anchor bolts 25mm dia 350mm depth. Most of such bolts are sheared on top and are to be replaced with new ones. Our Contract does not specify the type of anchor bolts i,e. to which spec it should conform. But it is clear that it should be like for like. So, we took the 20 year old embedded U bolt sample to a lab for chemical tests (the results are attached herewith). The chemical results are conforming to A 325 type 1, A490 type 1, and F1554 Grade 55.. Could you folks please put some light and help us identify the exact code for these bolts. We are in a process to test mechanical properties also... To make it more clear the structure is a concrete base slab 300mm thick, U bolts being embedded 250mm deep, protuding portion of the bolt is used to fasten rail clips to the 132 lb/yd rails used to carry Navy Ships for repairs. Thank You.

 

[Ron]

While your chemistry results might meet several different ASTM criteria, the mechanical properties might be significantly different...for instance ASTM A325 and A490 are usually only applied to straight, high strength bolts. U-bolts are usually made of mild steel that can be bent into different configurations without cracking.

I doubt that the bolts have much stress in service...they are probably used primarily to keep the rail in place.

 

[Ltwine]

Suggest to consult with rail clamp suppliers to check current availability on high strength anchor bolts that meeting your test results. Ron is correct that A325 & A490 do not fit your purpose.

 

[paddingtongreen]

Normally, I would agree with Ron that the bolts get little stress, but I think you need to know why the existing bolts are sheared off at the concrete.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[farhanjnawab]

What other codes have steel which can be bent have chemical results matching with mine?
I have tried to search most of the ASTM's for anchor bolts but came out with A325, A490, F1554 whose chemical values are similar to one tested.
Mild steel as per A36 has C value max upto 0.270 whereas our bolt shows 0.437. Can we argue with our Clients that irrespective of the C value we can still use A36 bolts (does chemical composition change after 20 years in service)

 

[Ltwine]

Check the link below, it may help.

http://www.portlandbolt.com/technicalinformation/astm/ASTM_F1554.html