Representatives of the Missouri Department of Transportation, MoDOT said that Business Highway 65/MO 76 Bridge across Lake Taneycomo is structurally sound and is in no danger of collapsing. The major problem that the bridge has is a deteriorating deck.
That information was part of an overall discussion that took place at a City of Hollister Work Session Meeting on Tuesday Aug. 7. The meeting, attended by representatives of MoDOT, the cities of Hollister and Branson, and Taney County, was held primarily to discuss, what most people call the “Lake Taneycomo Bridge and Hollister Roundabout” project. Early on, as the Lake Taneycomo Bridge was being discussed, the topic of the Interstate 35W Bridge disaster in Minneapolis last week came up.
Kirk E. Juranas, MoDOT’s District 8 Engineer, pointed out that the two bridges are of different styles and that the problems with the deck of the Lake Taneycomo Bridge relate more to pot holes and the damage that they can cause to vehicles than to the possibility of the bridge collapsing. In terms of bridge ratings, under MoDOT’s guidelines the bridge is rated a 3 on a scale of 0 through 9 with nine being the highest.
Under MoDOTs guidelines the three major components of a bridge, super structure, sub structure, and deck are each rated. David O’Connor, District 8 Maintenance Engineer and former MoDOT Bridge Engineer, who was not at the meeting but was contacted later, pointed out that the unusual architecture of the Business Highway 65/MO 76 Bridge, its open-spandrel arch design, as compared to most modern bridges, poses some challenges in terms of ratings.
He said that the bridge’s substructure, including piers and arches, is rated a 6, the deck, including the surface that vehicles drive on, is rated a 3, and its super structure, including the columns coming up off the arches is rated a 3. He went on to point out that the overall rating of 3 that the bridge received is based on the lowest rating of any of the three components being rated. Any rating of 2 would cause the bridge to be closed.
O’Connor said, “The bridge went from a 4 to a 3 rating during the last year.” He went on to point out that the primary reason for the the deterioration of the bridges deck was water and salt saturation.” From the general discussion that took place at the meeting, it appears that the 3 rating of the super structure is related to the unique architectural structure of the open-spandrel arch type bridge. Some of the floor beams, attached to the columns of the super structure coming up off the arches are poured as part of the deck. O’Connor stressed that there is minimal deterioration to the columns or the floor beams.
Chad E. Zickefoose, MoDOT’s District 8 Transportation Project Manager stated that the bridges deck will receive a scheduled one inch overlay this summer. He pointed out that although it would not increase the rating of the bridge it would help reduce the decks rate of deterioration, provide a temporary fix of about two or three years and provide users of the bridge with a more smooth ride.
Zickefoose also said that, “A Value Engineering Study” regarding the “Lake Taneycomo Bridge and Hollister Roundabout” project would be conducted Sep. 10-13. The recommendations of that study will serve as the basis for determining a long term solution to the decks problem and a determination if and for how long the bridge will have to be closed.
Furnished courtesy of the Branson Daily Independent.
