doka1
Structural
- Jan 7, 2009
- 66
I am a foreman for a concrete contractor on a 5 story steel structure building. The steel is being erected with 3/4" f1554 gr 55 anchor bolts. During the installation of the underground plumbing the plumbing contractor bent several anchor bolts. Of course bolts were bent to different degrees, one was sheared about 2 inches from the base, 3 were bent to the ground (runover), and about 10 were just bent. Having delivered the project with all anchor bolts intact, our position as always in such situations, is that it is not our responsibility for the repair of the bolts. We further expressed to GC that in such situations there are a number of repair procedures that must and should be followed. Without further information from the EOR we could not proceed on correcting the situation.
The GC did as we suggested and submitted an rfi regarding the situation, and added in the rfi the suggested fix was to core the bolts and epoxy new anchors as the anchor bolts are in fact in the right location. The EOR's replied agreed with the suggested repair and stated that any bolt bent any more than 45 degrees should be cored and epoxied.
When asked to begin work on the repair we reviewed with the GC the potential problems with such a procedure. The inability to oversize the core more than 1.5" and damaging rebar as some are in pedestals. Nonetheless, the work was started. Before coring any bolt we attempted to straighten each bolt. We did not apply any heat, and bent only about 5 degrees at a time, with rests between each bend slight bend of the rod. We were able to straighten out 11 of 14 bolts, and none of which showed signs of stress or cracks from being bent.
The GC would still like to see all the bolts the be cored and epoxied as they do not want to the deviate from the EOR direction. I stressed my concerns that we may be doing more harm than good by replacing all the bolts considering some stirrups and column steel may be cut during coring. Furthermore, all bolts are 3/4" which are typically for erection purposes only, so is it really necessary to go to such lengths. It does seem odd that a 5 story building to have only 3/4" anchor bolts, but I must mention the building does have a lot of steel bracing, this certainly has something to do with the sizing of the rods, correct?
In summary, I am just looking for some feedback on whether or not bolts bent more than 45 degrees can be salvaged. I understand that there are a lot of variable to determine whether or not this is possible, ie whether or not the bolt is in tension.
My issue is that the GC is taking an easy approach to the engineer's direction. I dont feel the engineer has fully analyzed the situation and understands the consequences or the feasibility of the repair. I feel the GC should suggest another option like welding (is that ok on f1554 gr 55?, or even offsetting a hole in the baseplate.
Your comments are appreciated!
The GC did as we suggested and submitted an rfi regarding the situation, and added in the rfi the suggested fix was to core the bolts and epoxy new anchors as the anchor bolts are in fact in the right location. The EOR's replied agreed with the suggested repair and stated that any bolt bent any more than 45 degrees should be cored and epoxied.
When asked to begin work on the repair we reviewed with the GC the potential problems with such a procedure. The inability to oversize the core more than 1.5" and damaging rebar as some are in pedestals. Nonetheless, the work was started. Before coring any bolt we attempted to straighten each bolt. We did not apply any heat, and bent only about 5 degrees at a time, with rests between each bend slight bend of the rod. We were able to straighten out 11 of 14 bolts, and none of which showed signs of stress or cracks from being bent.
The GC would still like to see all the bolts the be cored and epoxied as they do not want to the deviate from the EOR direction. I stressed my concerns that we may be doing more harm than good by replacing all the bolts considering some stirrups and column steel may be cut during coring. Furthermore, all bolts are 3/4" which are typically for erection purposes only, so is it really necessary to go to such lengths. It does seem odd that a 5 story building to have only 3/4" anchor bolts, but I must mention the building does have a lot of steel bracing, this certainly has something to do with the sizing of the rods, correct?
In summary, I am just looking for some feedback on whether or not bolts bent more than 45 degrees can be salvaged. I understand that there are a lot of variable to determine whether or not this is possible, ie whether or not the bolt is in tension.
My issue is that the GC is taking an easy approach to the engineer's direction. I dont feel the engineer has fully analyzed the situation and understands the consequences or the feasibility of the repair. I feel the GC should suggest another option like welding (is that ok on f1554 gr 55?, or even offsetting a hole in the baseplate.
Your comments are appreciated!
