bridgebuster
Active member
- Jun 27, 1999
- 3,969
I got sucked into another headache. Three elastomeric bearings that are partially delaminated from the masonry plate. The bearings in question are at an abutment. Photos and a framing plan are attached.
Bridge particulars: 3 span continuous stringer, W33x291; 10 stringers. Span lengths are 100’-110’-100’; deck with is 55’; 30-degree skew; expansion bearings at the abutment; fixed bearings at the piers.
The bearing at Girder 1 appears to have rotated ½” east; two bearings in the middle have rotated about ¼” east. No other bearings on this bridge or the adjacent bridge have delaminated. (The adjacent bridge is the one with the railing base plate spanning an expansion joint "Stupid Construction Questions").
The neoprene is vulcanized to the masonry plate. Is there any way to repair this? I waiting for a call back from the manufacturer but I’m interested in the experience of others. The owner is more interested in a repair rather than a cause.
There’s another thing that may or may not be related to the delamination problem: These bearings have been a headache since they were installed about 18 months ago. Every expansion bearing – on both bridges - leans more than what would be normally expected in the expansion direction at relatively mild temperatures – 70 degrees. They were reset once but the lean returned. Unfortunately I can’t get any information about the conditions under which the bearings were installed or reset; also no one in the office knows where the calculations are.
Last year when the leaning issue came up I was too concerned because the “excessive” lean was tolerable (elastomeric bearing tend to be forgiving). I did a check and the bearings have enough thickness.
Right now, I’m wondering if the problem is due to a manufacturing defect, an installation defect, a rotation of the superstructure, or a combination of these. I’ve seen skewed bridges that have rotated about the longer diagonal. However, the opposite span is fine and there’s no problem with the adjacent bridge. One other thing, at Bearing G1, there was a partial blow out in the end of the parapet formwork. A portion of the expansion joint was jammed. I'm wondering if somehow the bridge locked up resulting in damage the bearing. The end of the parapet is spalled.
Bridge particulars: 3 span continuous stringer, W33x291; 10 stringers. Span lengths are 100’-110’-100’; deck with is 55’; 30-degree skew; expansion bearings at the abutment; fixed bearings at the piers.
The bearing at Girder 1 appears to have rotated ½” east; two bearings in the middle have rotated about ¼” east. No other bearings on this bridge or the adjacent bridge have delaminated. (The adjacent bridge is the one with the railing base plate spanning an expansion joint "Stupid Construction Questions").
The neoprene is vulcanized to the masonry plate. Is there any way to repair this? I waiting for a call back from the manufacturer but I’m interested in the experience of others. The owner is more interested in a repair rather than a cause.
There’s another thing that may or may not be related to the delamination problem: These bearings have been a headache since they were installed about 18 months ago. Every expansion bearing – on both bridges - leans more than what would be normally expected in the expansion direction at relatively mild temperatures – 70 degrees. They were reset once but the lean returned. Unfortunately I can’t get any information about the conditions under which the bearings were installed or reset; also no one in the office knows where the calculations are.
Last year when the leaning issue came up I was too concerned because the “excessive” lean was tolerable (elastomeric bearing tend to be forgiving). I did a check and the bearings have enough thickness.
Right now, I’m wondering if the problem is due to a manufacturing defect, an installation defect, a rotation of the superstructure, or a combination of these. I’ve seen skewed bridges that have rotated about the longer diagonal. However, the opposite span is fine and there’s no problem with the adjacent bridge. One other thing, at Bearing G1, there was a partial blow out in the end of the parapet formwork. A portion of the expansion joint was jammed. I'm wondering if somehow the bridge locked up resulting in damage the bearing. The end of the parapet is spalled.
