Ever wonder how the bridges you drive over are kept in tip-top shape, so they don’t come crashing down on your next commute?
I visited the Georgia Department of Transportation (GDOT) with product designer Mike Myles to find that out. We also used that visit to validate ideas we had for a mobile bridge inspection app, because the most expensive mistake to make when creating a product is to build something nobody wants! More on what we learned and how we’ve incorporated them in our product development process, later.
Bridge inspections are mandated and regulated by the Federal Highway Administration (FHWA). There are 6 main types of bridge inspections, each with a prescribed inspection interval:
- Initial or Inventory Inspections – These are done no more than 90 days after a new bridge is put in service.
- Routine Inspections – These are done at 24-month intervals.
- Damage Inspections – These are done after an accident or a natural incident (hurricanes, earthquakes etc).
- Underwater Inspections – These are done at 60-month intervals.
- In-Depth & Special Inspections – These may follow the 60-month interval for inspections of bridges that require specialized equipment (for example cable stayed or suspension bridges) or may be conducted supplement to a routine, damage or initial inspection.
- Interim Inspections – These are scheduled at the discretion of the person in charge of an agency’s bridge inspection activities.
On our GDOT visit we met with two teams conducting routine inspections: A ‘top side’ team and an underwater inspections team. Top side teams are responsible for inspecting parts of a bridge that are above a water line, in cases where a bridge is over water. They are responsible for complete inspection on bridges not crossing water. Underwater, well it’s exactly what you think. These brave souls put on diving suits and inspect the parts of a bridge that are underwater, in all kinds of water conditions: clear, murky, fast moving and even the ocean.
Bridge inspections are typically conducted on a span by span basis, for multi-span bridges – a span is the horizontal space between two bridge supports. It’s like inspecting a mini bridge within a bridge. This allows inspectors to gather and report on findings efficiently on the bridge elements from one span to the next. The inspections process is similar for underwater bridge inspection, but differs in how the findings are collected – the designated diver inspecting elements and taking measurements whilst underwater and reporting findings to the onshore inspector.
For both inspections types, a critical finding on a bridge element can trigger supplemental in-depth inspection of the bridge, load rating recalculation, place the bridge on a scour critical list for monitoring or in severe cases closure of the bridge. These judgements are made on sight by the lead inspector, but are later reviewed by a regional supervisor upon submission of the inspection report. The reviewer ultimately approves or rejects the findings in the inspection report.
Clockwise from top L-R:
Bridge inspector retrieving equipment from their van at the site of an underwater inspection; Inspector examining a dive helmet with 2 bright tactical flashlight (for those murky waters); Dive inspector wading through water taking some measurements to check for settlement; Inspection supervisor recording findings communicated from the diver submerged in a lake.
This trip reinforced the importance of conducting field research with end users and/or customers, early in the product development process. A few of our pre-conceived ideas of the inspections process and requirements were quickly debunked. We learned, to be effective in the field, a bridge inspection app MUST function regardless of device connectivity (low connectivity or even offline). We also learned a great deal, the nuances of how routine bridge inspections are performed, that will inform the user experience and interaction design of the app.
The process of conducting early field research with users, is being replicated on our mobile work manager app and other initiatives. But that is fodder for another blog post, so stay tuned. Now you can feel a bit more relaxed the next time you’re driving 65 MPH on a 10 span bridge over a sea or fast flowing river, with an eighteen-wheeler in the next lane. You’re welcome!