LTAP’s bridge training to cover inspection, maintenance
"The collapse of the I-35W bridge should make us appreciate all the effort that goes into keeping bridges safe," says Ken Johnson, P.E., a consultant and former county engineer responsible for bridge inspection for the Aitkin County Highway Department. Johnson and Bob Kleinschmidt, a retired Mn/DOT senior engineering specialist, teach Minnesota LTAP’s Bridge Maintenance workshop. They shared their thoughts during a visit to our offices to plan the curriculum and schedule for the next round of their classes.
Wreckage from the collapse of the I-35W bridge in Minneapolis
Maintenance is the easiest way to extend life. "It can be as easy as flushing off deicers in the spring and sealing hairline cracks," Johnson explains. "The little things pay off."
In the wake of the collapse, Johnson says people should understand two things. First, bridge inspection is very important work even though at times it may not seem glamorous—such as when inspectors have to clean off pigeon droppings. Pigeon feces can contain a pathogen that causes respiratory disease and is very harmful to humans. It also is very corrosive for bridges.
Second, while the public should demand performance, "people also need to recognize that we’re still human," Johnson says. "The human element is still there."
The bridge inspector is the "foot soldier," Johnson says, and has to decide where further testing and analysis is needed. Other technologies such as ultrasound may then be used.
Local agencies can call in Mn/DOT’s Bridge Office for further analysis of suspect areas, notes Kleinschmidt. Mn/DOT’s Technical Memorandum No. 05-02-B-02 (72 KB PDF), issued in July 2005, establishes a formal procedure for responding, reporting, and documenting "critical deficiencies" found during scheduled bridge inspections. (The FHWA requires all states to have such plans.) A critical deficiency is defined as any condition discovered during a scheduled bridge inspection that threatens public safety and, if not promptly corrected, could result in collapse or partial collapse of a bridge. (This memorandum and others are online at www.dot.state.mn.us/tecsup/tmemo.)
Kleinschmidt says their revised workshop curriculum will correct misperceptions about bridge terminology—such as structural deficiency—that have appeared in recent media reports. Other topics will include gathering data on bridge maintenance needs, planning for bridge emergencies, and developing a scour response plan. (Scour of the riverbed near bridge piers and abutments is a major cause of bridge collapses.)
Kleinschmidt and Johnson bring decades of experience to their training. While with Bemidji’s construction inspection unit, Kleinschmidt supervised bridge maintenance operations and the bridge safety inspection program, and developed the annual district maintenance program. Johnson worked in the development and use of treated timber for highway bridges while with Wheeler Lumber, LLC.
Johnson hopes Minnesotans won’t lose confidence in their infrastructure. "Minnesota is a nationwide leader in transportation," he says, "and the bridge collapse was an anomaly. Many states have bridges in much worse condition."
Eventually investigators will determine the cause of the collapse, Johnson says, and the findings will help improve future bridge inspection processes. His wish is that the tragedy will reverse the general erosion of public support for infrastructure and move public policy toward greater investment.
Johnson and Kleinschmidt will share some tips for bridge maintenance in two one-hour sessions at the Minnesota Spring Maintenance Training Expo, April 15–16, 2008. The LTAP Bridge Maintenance workshops are being planned for later next year.
—Pamela Snopl, LTAP editor