Anchor bolt diameter?
Anchor bolt diameter?
(OP)
Public Works Issue-21' tall abutment with 26' span
I have an issue regarding anchor bolt diameters. AISC table J3.3 states for 1/2" dia. holes: std-9/16", oversize-5/8" and long slot- 9/16"x1 1/4" respectively.
I have a bearing plate on a pedestrian bridge that the fixed end has 3/4" dia. holes for the A307 1/2" anchor bolts and the sliding bearing end has 3/4"x1" slotted holes with 1/2" anchor bolts.
The engineer of record wants to fix the oversized holes by 'A': use a 1/2" washer over a 3/4" washer. Table 6.1 AISC (RCSC): ok if washers not thicker than 5/16". If both washers are at extreme for thickness tolerance, they will exceed 5/16". Or 'B' use 1/2" thick plate x 1 1/2" x 1 1/2" with 9/16" dia. hole.
My concern is that this criteria is for standard oversized holes, not larger than oversized holes as I have stated for my case. Am I interpreting this correctly? Also the washers or the 1/2" plate will bear next to a 1/4" fillet weld, this will result in the washers or plates taking the lateral force instead of the anchor bolts.
Thanks for any comments!
I have an issue regarding anchor bolt diameters. AISC table J3.3 states for 1/2" dia. holes: std-9/16", oversize-5/8" and long slot- 9/16"x1 1/4" respectively.
I have a bearing plate on a pedestrian bridge that the fixed end has 3/4" dia. holes for the A307 1/2" anchor bolts and the sliding bearing end has 3/4"x1" slotted holes with 1/2" anchor bolts.
The engineer of record wants to fix the oversized holes by 'A': use a 1/2" washer over a 3/4" washer. Table 6.1 AISC (RCSC): ok if washers not thicker than 5/16". If both washers are at extreme for thickness tolerance, they will exceed 5/16". Or 'B' use 1/2" thick plate x 1 1/2" x 1 1/2" with 9/16" dia. hole.
My concern is that this criteria is for standard oversized holes, not larger than oversized holes as I have stated for my case. Am I interpreting this correctly? Also the washers or the 1/2" plate will bear next to a 1/4" fillet weld, this will result in the washers or plates taking the lateral force instead of the anchor bolts.
Thanks for any comments!






RE: Anchor bolt diameter?
RE: Anchor bolt diameter?
RE: Anchor bolt diameter?
RE: Anchor bolt diameter?
DaveAtkins
RE: Anchor bolt diameter?
Those are for steel-to-steel bolted connections, not base plate connections.
RE: Anchor bolt diameter?
RE: Anchor bolt diameter?
RE: Anchor bolt diameter?
RE: Anchor bolt diameter?
RE: Anchor bolt diameter?
What is the determining factor as to whether you should use direct shear for base plates or not?
RE: Anchor bolt diameter?
RE: Anchor bolt diameter?
As the anchor bolts make contact, a concrete wedge breaks out and tries to slide up into the base plate. Friction then occurs which is used to resist the lateral force. It should not be assumed that all anchors make contact due to oversized holes. When forces get too large, use shear lugs. See AISC design guides 1 or 7.