Equipment World Digital Magazine
Issue link: http://read.dmtmag.com/i/674536
The truth is, while there are still a relativly large num- ber of structurally deficient bridges across the country, roughly 58,500, that figure has dropped in recent years. It's still not good, as the American Road & Transporta- tion Builder's Association estimates with current fund- ing levels, it would take 21 years to replace or upgrade all those bridges. Being labeled structurally deficient only means a bridge has at least one structural defect that needs to be addressed. It doesn't necessarily mean the defect is criti- cal, but it does sound ominous to the general public. To rectify and help prevent these defects from be- coming worse and leading to the need for a replace- ment or rebuild, bridge engineers turn to preservation techniques. These projects are designed to either sus- tain or improve the condition of a bridge that's already in good condition, but do not necessarily improve the structural integrity or even add capacity. The main pur- pose is restoration. As defined in the FHWA Bridge Preservation Guide, these techniques are "actions or strategies that prevent, delay or reduce deterioration of bridges or bridge ele- ments, restore the function of existing bridges, keep bridges in good condition and extend their life. Preser- vation actions may be preventive or condition-driven." Preventive maintenance Bridge preservation boils down to preventive mainte- nance (PM), which involves efforts to prevent deterio- ration and maintain, or even improve, the functional capacity of a bridge. PM steps that may extend bridge life include sealing or replacing leaking joints (or even eliminating deck joints altogether), deck overlays, ca- thodic protection (CP) systems for decks, electrochemi- cal chloride extraction (ECE) treatments and concrete May 2016 | EquipmentWorld.com 68 better bridges | by Chris Hill | ChrisHill@randallreilly.com Preservation programs grow as state DOTs battle challenging bridge conditions Dire statistics about bridge conditions in the U.S. make headlines every year; either through condition reports from the Federal Highway Adminis- tration's (FHWA) bridge inven- tory figures, our own Better Roads Bridge Inventory Report or through period state-level reports from the Road Improve- ment Program.