Krish Anchor bolt failure : happens due to : 1. Improper design and improper original specification / installation ( could be : wrong specfication of steel, improper physical sizing [length, depth of embedment, amount of pre-load applied at the time of equipment erecton and tightening)] 2. Improper maintenance due to not tightening of nuts whiah had become loose . Anchor bolts should be maintained with pre-load conditions when the equipment is in service. Have you analyzed the cause of the failure for adopting a sound and sure repair approach? Satisfactory repair welding of anchor bolts - one cannot be too sure especiallyon the integrity of oldused anchor bolt and the repair welding integrity. Mechanical threading with a coupling is a surer way of repair approach. If you have no time for this, as a temporary solution , you can attempt repair welding at the cut off portion of anchor bolt. Surere repair approach with mechanical threading or replacement of the anchor bolt can be taken up during a shut down of the equipment. Butt welding is possible - with single "U or V" double "U or V or even "J" bevel design" and welding using appropriate welding process (SMA process) and matching welding electrode. Are you sure that your anchor bolts are Carbon Steel only? Normally these should be AISI 4140 or EN 19 types - high strength low alloy grades - Cr-Mo types. If it is EN 19 or 4140 variety, be sure to pre-heat and post weld the welded area . Normal ASME SEC IX pre-qualification and welding repair can be done and can be adopted. If the anchor bolt is low alloy steel, successful repair welding may pose problems - you have to recognize this factor before welding repair. A surer way is to consider mechanical threading with a coupling nut tightening. This is my view only. Trust this is of help to you C.V.Srinivasan Nishi Engineers Pvt Ltd India Nov 11,2005 E-mail: nishi@vsnl.com >Dear memebers, >Iwould like to know whether any ASME procedure/weld details >are available to weld the broken foundation bolt for >euipment.(Butt weld).Give your opinion and prefered welding >methods/joint design. Dia of bolt is 62 mm,carbon steel. > >regards

Krish Should be OK. You have to think of epoxy adhesive for good bonding between excavated old concrete and the new concrete with reinforcing rods. Epoxy adhesive compounds are available to have good bonding between old concrete and new concrete. Choose the appropriate brand of epoxy system and wait for curing before tightening to pre-load tension for good anchorate tightening. Importantly : You have to make sure to have the same pre-load tightness for good anchorage in all botls replaced. May be it is worth to have strain gauge measurement record, after pre-load tightening and known torque, at the new anchor bolts and the remaining foundation bolts for future comparison. Trust this is of help to you C.V.Srinivasan Nishi Engineers Pvt Ltd India Nov 14,2005 E-mail: nishi@vsnl.com >Thanks to shri srinivasan for reply. The fact is due to >corrosion the old anchor bolt is severely eaten away due to >water entry.We are planning to excavate the foundation up to >sound portion of old carbon steel bolt and corroded will be >replaced with new one with top thread.Any suggestion? >regards.