From the Editor: Personal and Mass-Media Stories Highlight the Importance of Inspections
During my career, I’ve performed inspections on hundreds of bridges. The inspections varied in detail depending on the reasons for looking at them.
Some were cursory inspections to determine whether or not to include particular bridges in the INDOT program for replacement or rehabilitation. There were some general criteria to follow about geometrics and structural condition, but a lot was left up to inspector experience. A couple of us would inspect five to 10 a day, mostly depending on how far it was between bridge locations.
Some inspections were more detailed to meet the requirements of the biennial National Bridge Inspection Standards. Depending on the size of the bridge, these may have taken the entire day or longer.
But the most-challenging inspections were those required because of some reported damage or failure, which required knowledge about the bridge as well as the cause of damage or deterioration.
While I was working in Indiana, we received a call that a bridge had caught on fire. It was a first for me. The bridge was a timber structure, and although details were sketchy, it was assumed this was a case of arson. The timber deck had burned through in a 10-foot-diameter approximate circle, and the tops of the timber beams were charred. We recommended replacing the timber decking in that area and reduced the load limit. We left it in service and immediately began preparing replacement plans.
Another unique instance for me was when a tornado passed over an old through-truss bridge and “relocated” most of the timber decking in the river below, leaving the rest tangled in the steel members. As with many tornado stories, this tornado appeared to cause no more damage to the surrounding area except for two trees and the timber deck. We spent hours climbing all over the structure looking for any signs of distress. Finding none, we replaced the timber transverse decking and added new longitudinal runners.
I’m not sure of the exact year, but sometime in the early 1980s, Indiana had record rainfall events in the northern half of the state. This prompted some concerned calls from the two northern districts that water levels were reaching the bottom of beams in several locations. Previously, the high-water record shown on our plans was from 1913 (if I remember correctly), but since that series of storms, the record level was revised.
I was flown by state helicopter from bridge site to bridge site to determine whether or not to close the bridge until the water receded. I remained on the safe side and asked all of them to be closed. I was fairly certain these older structures weren’t designed to withstand the transverse forces of water and debris, let alone the potential of “floating” the superstructure off its bearings. I might add that some of the helicopter landings were in parking lots where we were met by cars to get us to the bridge. Some of the landing sites were close to the bridge sites, but a little scarier than a parking lot.
When I was in Florida, I learned that climbing down around an end-bent to look at the underside of a bridge can offer surprises. More than once, as I turned the corner to get under the beams and look at the bearings, I found a snake resting there. I do not know which types of snakes they were, but I did report that the bearings looked just fine.
In Jacksonville, Fla., there are a few high-level bridges providing ship clearance over the St. Johns River. Some of them had grate decks and narrow sidewalks, which are bad enough on their own, but add to that the vertical clearance of 120-150 feet, and it becomes a different type of inspection experience. I had the opportunity to walk across a few of these doing a cursory inspection of the decks, and I will admit I didn’t thoroughly enjoy the task. At least I wasn’t part of the crew that did the major inspections with the bucket trucks!
Global Importance of Inspections
I’m sure many of you have interesting inspection experiences, and all of them are extremely important. We’ve all been following the details of the horrible collapse of the Champlain Towers South in Surfside, Fla., the cover story of this issue. That unfortunate event has brought to the forefront the imperative of proper and regular inspections of structures and the necessity to take action when inspections show the need. Let us at least learn that lesson.