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Langdon Street Bridge Project subsection links Project Description | Project timeline | Project Plans | Contacts |
Background
| The Langdon Street Bridge was built in 1928, after the Flood of ’27, as part of the massive statewide effort to replace damaged and destroyed structures. The bridge is one of the standardized designs used during this reconstruction era which enabled a very efficient replacement process through mass production. It is generally known as a Warren type pony truss with curved top chords. The bridge has served the City well, but through the course of time, and demanding conditions including environmental and vehicle load impacts, this steel structure is currently structurally deficient and is no longer capable of supporting today’s vehicle loads without rehabilitation or replacement. In fact, the condition of key structu ral components has deteriorated to an unsafe level, and in 1990 the City Council ordered the closure of the bridge. As an interim measure to re-open the crossing, reinforcing I-beams spanning the abutments were placed inside of the trusses to support the bridge deck. This supplemental support now carrying the majority of the deck load, occupies space formerly used for parking on the bridge. |
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The City has been engaged in discussions with the State Agency of Transportation (VTrans) since the mid-1980s, and in 1988 we were successful in obtaining eligibility for State and federal funding assistance as part of the Town Highway Bridge Program. VTrans accepted responsibility for project development, including engineering and right-of-way services. Discussions ensued about rehabilitation and replacement options, and a number of alternatives were developed and considered. The Langdon Street bridge is listed as an historic structure located in an historic district as classified by the Vermont Division for Historic Preservation. Therefore, and quite appropriately, much of the design consideration focused on preservation to the extent feasible, thus assigning greater weight to this alternative. This aspect of the project development process is consistent with the community’s expressed interest in the bridge and with State and federal law. |
| The Montpelier Planning office initially took a lead role in the project development process, holding meetings with the Langdon Street merchants. Furthermore, the . In . A , and the . Also in 1996, the City received word that recent legislation had altered the City’s local funding share requirement from 10% to 5% for projects that include rehabilitation instead of reconstruction |  |
Description of the Project
| The project, as currently designed, consists of replacing the bridge deck with a pre-cast structure known as an Inverset bridge which is constructed of steel beam and concrete decking, tied together with steel diaphragms. The new concrete deck surface will be surfaced with a sheet membrane for protection and covered with asphalt pavement. The existing pony trusses will be completely rehabilitated off site, including the attached sidewalks super structure, and then reinstalled in their former position. The existing granite block abutment walls and bridge seat will be rehabilitated and prepared to support the new Inverset structure. To all appearances, the new bridge will be indistinguishable from the existing structure to most people, but the trusses will bear only the weight of the sidewalks, railings and pedestrians, not the entire bridge deck. Mr. Kitzmiller explained that this option was “selected because it maintains the character and look of the existing bridge”. It was also explained that construction impacts, and particularly project duration, were also thoroughly considered. Essentially, the project is similar to the rehabilitation approach used for the School Street bridge, except the School Street bridge trusses no longer support either the deck or the sidewalks. |  Bridge with pedestrian walk removed, August 11, 2006 |
The project is estimated to take about 18 weeks from start to finish, with the bridge closed for approximately six weeks. A temporary footbridge is planned to extend from the Washington County Courthouse parking lot on Elm Street to the parking lot behind the former Mountain Café on Langdon Street. When finished, the new bridge will accommodate the six parking spaces (3 on each side) that were lost when the temporary shoring was placed on the bridge. The new bridge will occupy the same footprint as the old. The trusses and handrail will be painted black. The handrail will be the same as the railing on the School Street Bridge and there will be curbs and a rub rail along the street to which parking meters will be attached, also similar to School Street. Other work included with the project consists of sidewalk reconstruction (concrete with granite curb) on both sides of the bridge, as well as some street paving. The sidewalk improvements will extend along both sides of the street from the driveway at Onion River Sports to the Elm Street intersection.
People may also be interested to learn more about the bridge and historic considerations which can be found in a report by A.G. Lichtenstein & Associates dated January 1997, copies of which are available on request from the Pubic Works office. This report was commissioned by the VT Division for Historic Preservation and is part of a statewide review of the historic truss bridge inventory and is highly regarded as a useful guide in determining rehabilitation / preservation alternatives and feasibility.
Incidentally, the bridge design selected will allow for consideration of adding the North Branch River Walk at any point in the future, if that project moves forward.
Project Timeline (tentative)
| Description | Duration | Early Start | Early Finish |
| Pre-closure | 7/10/06 | 9/03/06 | |
| 635.11 Mobilization | 2 days | 7/10/06 | 7/11/06 |
| 210.10 Clearing & Grubbing |
1 day | 7/12/06 | 7/12/06 |
| 621.90 Temporary Traffic Barrier | 1 day | 7/12/06 | 7/12/06 |
| 203.15 Common Excavation | 5 days | 7/13/06 | 7/19/06 |
| 629.20 Adjust elevation of valve box | 1 day | 7/20/06 | 7/20/06 |
| 604.42 Change elevation of sewer main | 1 day | 7/20/06 | 7/20/06 |
| 604.40 Change elevation of drop inlets | 1 day | 7/20/06 | 7/20/06 |
| 301.15 Subbase of gravel | 5 days | 7/21/06 | 7/27/06 |
| 528.12 Temporary pedestrian bridge | 5 days | 7/20/06 | 7/26/06 |
| 616.40 Removing & resetting curb | 3 days | 7/21/06 | 7/25/06 |
| 616.21 Vertical granite curb | 3 days | 7/27/06 | 7/28/06 |
| 618.10 Portland Cement concrete sidewalk | 5 days | 7/31/06 | 8/04/06 |
| 618.30 Detectable Warning Surface | 1 day | 8/07/06 | 8/07/06 |
| Install containment / work platform | 5 days | 7/27/06 | 8/02/06 |
| 675.50 Removing Signs | 1 day | 7/31/06 | 7/31/06 |
| Closure of Bridge | 42 days | 9/04/06 | 10/15/06 |
| 641.10 Traffic Control (barricades) | 1 day | 9/01/06 | 9/05/06 |
| 529.10 Removal of Bridge Pavement | 1 day | 9/05/06 | 9/06/06 |
| 203.17 Unclassified Excavation | 2 days | 9/06/06 | 9/08/08 |
| 648.10 Removal of Parking Meter Posts | 1 day | 9/05/06 | 9/06/06 |
| Remove Containment / Work Platform | 3 days | 9/06/06 | 9/11/06 |
| 529.15 Removal of Structure | 8 days | 9/11/06 | 9/19/06 |
| 529.20 Partial Removal of Structure | 2 days | 9/19/06 | 9/21/06 |
| 507.16 Drilling & Grouting Dowels | 1 day | 9/19/06 | 9/20/06 |
| 507.15 Reinf. Steel & Conc. H.P. Class B | 3 days | 9/20/06 | 9/23/06 |
| 501.34 Curing Concrete H.P. Class B | 5 days | 9/23/06 | 9/28/06 |
| 506.50 Str. Steel (rolled beam) | 5 days | 9/21/06 | 9/26/06 |
| 506.60 Str. Steel | 5 days | 9/21/06 | 9/26/06 |
| 525.15 Metal Hand Railing (mod) | 5 days | 9/21/06 | 9/26/06 |
| 513.36 Containment | 2 days | 9/26/06 | 9/28/06 |
| 531.41 Surface Prep (field) | 5 days | 9/28/06 | 10/03/06 |
| 531.10 Bearing Device Assembly (inverset) | 1 day | 9/28/06 | 9/29/06 |
| 531.10 Bearing Device Assembly (Trusses) | 1 day | 9/28/06 | 9/29/06 |
| 525.30 Bridge Railing (Galv.) | 2 days | 10/03/06 | 10/05/06 |
| 513.30 Structural Painting (field) | 2 days | 10/05/06 | 10/06/06 |
| 510.23 Prestressed Conc. Girders | 1 day | 9/29/06 | 9/30/06 |
| 507.17 Epoxy Coated Reinf. Steel | 2 days | 10/07/06 | 10/09/06 |
| 516.10 Bridge Expansion Jt. | 1 day | 10/07/06 | 10/08/06 |
| 501.33 Concrete, H.P. Class A | 1 day | 10/09/06 | 10/10/06 |
| 519.20 Sheet Membrane waterproofing | 1 day | 10/10/06 | 10/11/06 |
| 301.15 Subbase of Gravel | 2 days | 10/11/06 | 10/13/06 |
| 616.21 Vertical Granite Curb | 1 day | 10/13/06 | 10/14/06 |
| 524.20 Joint Sealer | 1 day | 10/10/06 | 10/11/06 |
| 406.25 Bituminous Concrete Pavement | 1 day | 10/14/06 | 10/15/06 |
| Reopen Bridge | 10/15/06 | 10/24/06 | |
| 514.10 Water Repellent (mod-Silane) | 1 day | 10/10/06 | 10/11/06 |
| Remove temp. pedestrian bridge | 3 days | 10/15/06 | 10/18/06 |
| 648.11 Parking Meters | 1 day | 10/15/06 | 10/16/06 |
| 675.341 Square Tube Sign Posts | 2 days | 10/18/06 | 10/20/06 |
| 675.60 Erect Salvaged Signs | 1 day | 10/20/06 | 10/23/06 |
| 675.20 Traffic Signs, Type A | 1 day | 10/20/06 | 10/23/06 |
| 621.85 Guide Posts (mod) | 1 day | 10/18/06 | 10/19/06 |
| 646.51 Durable Crosswalk Marking | 1 day | 10/15/06 | 10/16/06 |
Conceptual Project Plans
The following 8.5"x11" plans can be downloaded from the links below:
The Final Scoping Report and full sized scoping plans for this project are available for viewing at the Department of Public Works.
For More Information
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Department of Public Works Montpelier City Hall 39 Main Street Montpelier, VT 05602-2950 Phone: (802) 223-9508 FAX:(802) 223-9524 Administration Todd Law, Director of Public Works, tlaw@montpelier-vt.org Thomas McArdle, Assistant Public Works Director, tmcardle@montpelier-vt.org Ginny Mackey, Administrative Assistant, gmackey@montpelier-vt.org |
Posted October 4, 2007
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