Preserva on Assessment

Transcription

1 Preserva on Assessment For Bardo Road Over Li le Fishing Creek BMS # Columbia County PennDOT Engineering District 3 0 Prepared by TranSystems Final Report Dec 2017 for the Pennsylvania Department of Transporta on Environmental Policy and Development Sec on

2 BRIDGE LOCATION LOCATION VICINITY N BRIDGE LOCATION MAP Bardo Road (T-536) over Little Fishing Creek Greenwood Township, PA Source: PA Type 10 Map Columbia County

3 RESOURCE LOCATION QUADRANGLE LOCATION SCALE SOURCE N 0ft 2000ft USGS 2013 Lairdsville, PA Bardo Road (T-536) over Little Fishing Creek Greenwood Township, Columbia County, PA

4 PENNSYLVANIA METAL TRUSS BRIDGE PRESERVATION/REHABILITATION ASSESSMENT EVALUATIONS The purpose of this assessment is to provide a benchmark analysis in which to understand rehabilitation options based on existing conditions of the bridge and adjacent areas at the time of the analysis and the observed usage. This assessment is not a Historic Bridge Rehabilitation Analysis, with purpose and need established, and a more in-depth study may be required if the project is to be further developed. The ability of this analysis to determine whether the bridge can be rehabilitated to meet project need is constrained by the fact that actual need is not established for this analysis and that data utilized is based on a field view, file research, and chance interviews with local parties. When actual project need is established, this information will be updated based on current field data. A final determination of whether rehabilitation can meet the project needs and would be considered feasible and prudent under Section 4(f) of the USDOT Act of 1966 will be determined during the NEPA/Section 4(f) process. BMS #: Bridge Key #: District: 3-0 County: Columbia Township: Greenwood Owner: Columbia County Maintenance: Columbia County Location Information: 2.5 Miles Northeast of Millville Bridge Name: Bardo Road (T-536) Over Little Fishing Creek Columbia County Bridge No. 89 Type: Pony Truss Design: Pratt Truss Material: Steel Date: 1896 Alter/Rehab: 2011 (Truss Repairs) Source: Inspection File Length: 54-0 Number Spans: 1 Deck Width: 14-7 (center-to-center truss) Bridge Description The bridge carries one lane of a township road over a stream in a sparsely developed area. The one span, 47'-long, 3 panel, pin connected Pratt half-hip pony truss bridge is supported on stone abutments with flared wingwalls and later, concrete toe walls. The trusses are traditionally composed with built up box section upper chords and end posts and back-to-back angles with lacing for the verticals. The diagonals and lower chords Bardo Road Bridge Assessment Page 1

5 are eye bars. There is a repair to the lower chord on the upstream side. There is a welded repair to member U2-U3 on the east truss. NR Eligibility Status: Although this bridge was considered eligible at the onset of this assessment, the 2017 reevaluation of the metal truss bridge population determined the bridge to be not eligible. Historic Preservation Priority Justification: The bridge has no innovative or distinctive details. It reflects the period of design standardization that dominated after about Rolled floorbeams and stringers support the timber deck. Any original railings have been lost. The bridge is not historically or technologically significant within the regional population of early and complete truss bridges. Over 120 examples were built between about 1880 and the 1940s. There is highly altered, ca vernacular house and barn beyond the north end of the bridge. The character defining features include the truss form and method of truss member end connection (pinned Pratt half-hip pony truss), the upper chords (box sections), and the end posts (back-to-back angles). Roadway & Site Information Setting Description: The bridge is on Bardo Road south of an intersection with Sereno Hollow Road in Greenwood Township. The bridge carries one lane unimproved township road over Little Fishing Creek. The surrounding area is largely wooded, in a rural setting with fields to the northeast and southwest. A few homes are also present in the vicinity. The 11-6 bridge roadway width (rail-to-rail) is approximately the same width as the maintained approach roadway. The bridge and road have a very low reported volume (ADT 100). Type of Bridge Service: One lane (less than 18'-wide travelway) serving two-directional traffic. Bridge Roadway Width: 11-6 rail-to-rail Approach Travelway Width: 12-0 Minimum (at north) Vertical Clearance: N/A. Functional Classification: Rural Local ADT(Date): BMS2 lists a current ADT of 100 vpd (2016) is projected as 155 in The source of the BMS traffic count on the bridge is not known. Since AASHTO guidance on bridge width is founded on the number and types of vehicles that use a bridge, starting with an accurate assessment is critical, especially when the ADT on a rural local road is less than 400 and is projected to remain under Bardo Road Bridge Assessment Page 2

6 400 for 20 years. When bridges that do not meet current design criteria (functionally obsolete) are located on very low volume local roads and are performing satisfactorily (absence of documented crash history), AASHTO policy affords the opportunities to keep functionally those bridges in service. Shoulders/Sidewalks: None Observed Crash History: The rail ends exhibit minor scrapes but the truss and bridge rail do not exhibit any signs of previous impact. Specific crash history data (from local police) was not available for this site, so observed conditions of impact were used to make a determination. Damage appears to be from isolated incidents and is not a continual problem. Safety Features: The bridge railings consist of Type 2-S guiderail welded to the exterior stringers. The guiderail continues off of the bridge and terminate immediately as turned down Type 2 Strong Post End Treatments. Proximity of Alternate Routes: To reach the south side of the bridge on Bardo Road, one alternate route is available. The alternate route is 1.1 miles long using Sereno Hollow Road and Mallard Road to bypass 0.3 miles on Bardo Road. There are no height or weight restrictions on this alternate route. The actual additional length traveled would be dependent on the ultimate origin and destination of the individual traveler as the local roadway network is fairly well developed to permit sufficient connectivity. Summary Geometric Deficiencies: With a bridge deck roadway width of 11-6, the bridge is classified as functionally obsolete because it does not meet the 18' definition of a two lane facility. The bridge s approaches are curved at both ends, however sight distance does appear satisfactory for the site, especially given the low daily traffic for the bridge. Performance Summary: While it does not meet current design requirements, there is minimal evidence of a crash history on the structure and therefore it appears that the bridge is operating in a safe manner for those vehicles permitted to use the bridge. The bridge has been weight restricted for 3 tons. Hydraulics: Little Fishing Creek flows east to west. No undermining of the substructure units was observed. The waterway opening is satisfactory. There is a slight chance of overtopping, as per BMS2. BMS Condition & Load Sufficiency Condition Code Ratings (2016) Superstructure: 5-Fair Substructure: 5-Fair Deck: 6-Satisfactory Bardo Road Bridge Assessment Page 3

7 Controlling Load Ratings Inventory: 5 T Operating: 8 T Method: Load factor (floorbeams & stringers) Allowable Stress (truss) Posted? Yes. 3 Tons. LOAD FACTOR METHOD (unless noted otherwise) STRUCTURAL MEMBERS H20 (20 Tons) HS20 (36 Tons) ML80 (37.74 Tons) TK527 (45 Tons) EXT. STRINGERS (inv.) 16* 28* 25* 31* EXT. STRINGERS (opr.) * INT. STRINGERS (inv.) 5* 9* 8* 10* INT. STRINGERS (opr.) 9* 15* 13* 17* (1) FLOORBEAM (inv.) 5* 7* 5* 10* (1) FLOORBEAM (opr.) 8* 12* 9* 11* (2) TRUSSES (inv.) 7* (3) 14* (3) 14* (4) 15* (5) (2) TRUSSES (opr.) 12* (3) 22* (3) 22* (4) 24* (5) (1) Controlling Members (in red) (2) Allowable Stress Method (3) Member U1L2 Controls (4) Member U2L3 Controls (5) Member U4L3 Controls (*) indicates insufficient capacity The latest analysis is from 2012 and incorporates the structural repairs during the 2011 rehab. The floorbeams control the ratings. The controlling truss members is U1L2 with a posting of 7 tons. For truck loading schematics showing the axle loads, see Appendix. The inventory rating level results in a live load which can safely utilize an existing structure for an indefinite period of time. The operating rating level generally describes the maximum permissible live load to which the structure may be subjected. Allowing unlimited numbers of vehicles to use the bridge at operating level may shorten the life of the bridge. Summary Structural Deficiencies The bridge is rated in overall fair condition (5). The condition of the superstructure and substructure controls the condition rating. Based on BMS2 data, confirmed by a cursory field view, the following specific deficiencies were observed. Refer to photographs for additional details. Truss Lines Truss members exhibit isolated areas of moderate to heavy rust with minor pitting. Bardo Road Bridge Assessment Page 4

8 The upper chord cover plate is rippled in some areas due to rust. As much as 75% of previous section loss to the truss members has been repaired during the 2011 rehab. The low chords at the bearings have been repaired with welding of the eyebars. Exterior bar L2L3 is slightly loose There is severe section loss on interior vertical hanger plates at right end of floorbeam 2 below pin area Bearings The bearings have been rendered useless in their ability to allow for rotation and thermal movement from their encapsulation in concrete. They were not visible due to the new full depth diaphragms and backwall. Floorbeams The floorbeams had new top flanges welded to existing. The original beams exhibit areas of pitting due to prior corrosion and areas of light to moderate spot rusting. Stringers The steel stringers were replaced during the rehab. There is isolated spot rust on the top flange, web of fascia stringers, and bottom flange at areas of lower lateral which were not able to be painted. The bottom flanges of the stringers are welded to te top flange of the floorbeams. Paint Condition The paint is in fair to poor condition. The bridge has areas pf light to moderate spot rust throughout. The truss members have areas of heavy pitting. Substructure The stone masonry abutments and wingwalls exhibit cracks and mortar loss throughout with some areas of loose or missing stones. There is moderate cracking in the footing and concrete is exposed in front of the base footing. Deck There are minor checks, scrapes, and splits along the sides of the timber deck. There are a few minor missing clips along the underside of the deck. The deck is not securely attached to te top of the beams and bounces under live loads. Rehabilitation & Preservation Considerations Benchmark for Assessing Rehabilitation The existing bridge is located on a very low volume local road with an extremely low reported volume of traffic. There is a nearby alternate route as detailed on Page 3 that provide access to the adjacent areas of the bridge. It needs to be determined if a bridge is necessary at this crossing and if making the needed structural repairs to make it satisfactory could be undertaken. The Bardo Road Bridge Assessment Page 5

9 bridge has structural deficiencies related to deterioration of the trusses, floor system and the coating system. There are conventional treatments to correct the deficiencies. Specific Options to Address Existing Conditions and AASHTO Criteria The options considered strive to address the documented structural deficiencies associated with the physical condition of the bridge, such as failing paint and related corrosion. Traditional treatments for improving load carrying capacity based on the capacity of the trusses are considered. This analysis is based on considering options that make the bridge structurally satisfactory while preserving what makes it historic. Options for addressing the deficiencies are divided into four categories (1) maintenance; (2) rehabilitation without adverse effect; (3) the option of building on a new location without using the old bridge and (4) other reasonable options. Maintenance The bridge was recently rehabilitated and repainted. There are conventional and cost effective treatments that could be performed on a routine basis in order to maintain this work and significantly reduce life cycle costs, like cleaning the bridge to maximize the life of the coating system. Rehabilitation without Adverse Effect Section 106 of the National Historic Preservation Act of 1966 (NHPA) requires federal agencies to take into account the effects of their proposed improvement on historic properties. An adverse effect on an historic resource occurs when the proposed improvement alters the character defining features that qualify the property for inclusion in the National Register. Adverse effects can be avoided by rehabilitating the structure to the Secretary of Interior s Standards for Rehabilitation. This could be accomplished by implementing the following rehabilitation program. Rehabilitation of the bridge would include conventional treatments that would not alter the characteristics that make the bridge historically significant. Structural deficiencies can be addressed by replacing deteriorated sections or the entire members of the truss and flooring system with an in-kind repair or total replacement. A No Adverse Effect is likely as long as the existing end connection details are utilized (pinned truss members and the floorbeam connection detail). Rivets do not need to be utilized for built-up members. Truss strengthening to achieve a higher load capacity can also be achieved without adverse effects by in-kind replacement with a higher strength material or providing a secondary support system (i.e. post-tensioning or adding supplemental members). The existing truss polytetrafluoroethylene (PTFE, better known as Teflon ) expansion bearings and steel fixed bearings would be cleaned and/or repainted. The repair of the substructure units will not adversely affect the historic significance and cultural value of the bridge if properly performed, as they are not considered character defining features. Appropriate placement of safety features to protect motorists and the truss lines is also permissible. The existing bridge railings are not original and could be removed and new railings installed, which are not attached to the trusses. Bardo Road Bridge Assessment Page 6

10 The following budgetary cost estimate has been developed (utilizing unit costs generated from previous truss rehabilitation projects and modified to reflect specific site constrains/conditions) to provide a rehabilitated structure that makes the bridge satisfactory for this site and meets a 15 ton minimum capacity. This value is the generally accepted minimum load carrying capacity for rehabilitated structures and represents the anticipated weights for a school bus, oil delivery truck, and small emergency service vehicle. Based on a review of the available structural analysis, it appears that a rehabilitation that results in a 20 ton weight limit would be possible without adverse effect; however, 18 additional truss members would require strengthening. If additional carrying capacity is determined to be required when a purpose and need is developed for the project, additional analysis would be needed. This would be addressed by means of additional analysis during the NEPA process. Cost Model - Rehabilitation Program for 15 Ton Capacity Remove Portion of Existing Bridge L.S. $25,000 Temporary Superstructure Support L.S. $100,000 Truss Bearings $10,000 $40,000 New Stringers 3 x 49 x 21#/ft = 3,100lb x $3.50 $10,850 New Floorbeams 2 x 15 x 50#/ft = 1,500lb x $5.00 $7,500 Truss Strengthening $10,000 $120,000 Pointing 150 $30/SF $4,500 Reset Loose Stones 25 $150/SF $3,750 Clean & Paint Superstructure L.S. $250,000 Subtotal: $561,600 20% $112,320 TOTAL: $673,920 Considering a 25 year life-cycle analysis that includes a 3% inflation rate and yearly flushing of the truss and bridge seats and spot cleaning and painting, the following costs should be added to this cost model. The cost does not include engineering, mobilization, maintenance and protection of traffic, erosion control measures, etc. Flushing Truss/Bearing Area $1,000/YR 25 ($1,550 ave.) $38,750 Spot Cleaning & Painting 15 years $38,950 TOTAL: $77,700 The cost model yields a total rehabilitation program in present dollars equal to $755,000. The cost for a bridge replacement is estimated to be approximately $1,200,000 based on similar statewide projects. The cost does not include engineering, mobilization, maintenance and protection of traffic, erosion control measures, etc. Bardo Road Bridge Assessment Page 7

11 Other Reasonable Options For Reuse This is a very low volume local crossing, and there is a sufficient alternate route to access properties on either side of the bridge. Although meeting any likely need, the cost for building a new bridge on a new alignment in close proximity to the existing structure while leaving this historic bridge in place is essentially the same as replacement. Ownership and maintenance of the existing bridge is left undetermined, which might not be conducive to long-term preservation. If it is determined that the actual need does not require a crossing at this location, then removal, relocation, and rehabilitation of the existing structure to the Secretary of Interior s Standards for Rehabilitation is an option that could also result in a No Adverse Effect. Likewise, if construction of a new bridge is required based on the project needs, then the removal, relocation, and rehabilitation of the existing structure to the Secretary of Interior s Standards for Rehabilitation is also an option that could result in a No Adverse Effect. That work would still require that the truss deficiencies be addressed and the bridge cleaned and painted. Due to the length of the span, it is anticipated that this would involve dismantling, rehabilitating, conserving and then relocating the truss for reuse. Summary of Rehabilitation Options Ultimately, the investment into a rehabilitation of a historic bridge works best when there is a long-term potential for preservation. Because of that goal, there is a hierarchy of rehabilitation options. Highest is the rehabilitation of the existing bridge at the current location that continues to meet transportation need at that crossing. Below that is a relocation and rehabilitation of the bridge to another crossing or rehabilitation of the bridge on existing location for a use other than the transportation need. The least preferred option is dismantling and storage of the historic bridge for a future use. This provides no assurance that the bridge will ever be rehabilitated and re-used, and would result in a finding of adverse effect. Based on the observed conditions and usage prior to closure, the Bardo Road Bridge could be rehabilitated to carry 15 tons without altering its character defining features and could still be eligible for the National Register. The cost of the rehabilitation would be less than the cost of a new bridge. There are definite challenges to moving forward with rehabilitation due to the work that must be done to address deterioration of the truss members, but rehabilitation appears to be a cost effective option. With conventional treatments for repairing or replacing these elements on the trusses and cleaning and painting the trusses with a properly done coating system, it is likely that the bridge would last a minimum of 25 years with routine maintenance. If construction of a new bridge is required at the crossing based on project needs or if the actual need does not require a crossing at this location, removal, relocation, and rehabilitation of the bridge would likely result in a No Adverse Effect finding and provide utility of the structure in another use. That use could be in a transportation purpose or in a non-vehicular use. Bardo Road Bridge Assessment Page 8

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16 Photo 1: View from the South Approach Looking North, Approximately 200 from Bridge Photo 2: View from the North Approach, Approximately 200 from Bridge Bardo Road Bridge Assessment Photo Page 1

17 Photo 3: Elevation View Looking Northwest (Downstream) from Southeast Corner Photo 4: Elevation View Looking Northeast (Upstream) from Southwest Corner Bardo Road Bridge Assessment Photo Page 2

18 Photo 5: Top of Concrete Pour at South Abutment; Concrete Encapsulates the Bearings and Joints at the Abutments Photo 6: General Deck View from Southwest Looking North Bardo Road Bridge Assessment Photo Page 3

19 Photo 7: Typical Light Wear of Timber Deck Photo 8: Pinned Connection at Joint U1, West Truss Bardo Road Bridge Assessment Photo Page 4

20 Photo 9: Typical Upper Chord Pinned Connection; Joint U2, West Truss Shown Photo 10: Splice in Member U1 U2 in Relation to Joint U2, West Truss Bardo Road Bridge Assessment Photo Page 5

21 Photo 11: Close Up of Splice in Member U1 U2, West Truss (East Truss Typical) Photo 12: Member U2 U3, West Truss; Note Distortion in Top Plate Due to Rust Packing at Rivet Locations Bardo Road Bridge Assessment Photo Page 6

22 Photo 13: Typical Pinned Floorbeam Connection; Joint L1, East Truss Shown Photo 14: Typical Floorbeam Connection, Joint L3, East Truss Shown Bardo Road Bridge Assessment Photo Page 7

23 Photo 15: Peeling Paint and Surface Rust at Joint U5, West Truss Photo 16: Rust Along Member U4 L5, East Truss at Rivet Locations Bardo Road Bridge Assessment Photo Page 8

24 Photo 17: Welded Repair of Member L0 L1, East Truss; Typical at West Truss and North Abutment Photo 18: Repair to Member U2 U3 at Joint U3, East Truss; ¾ Thick Plate is Welded to Member Bardo Road Bridge Assessment Photo Page 9

25 Photo 19: Member Repair at Joint U3, East Truss Extends to Member U3 U4 Photo 20: Rusting of Counter Members at Intersection, Panel 2 (Typical) Bardo Road Bridge Assessment Photo Page 10

26 Photo 21: Typical Deck Underside, Looking South Photo 22: North Abutment Bardo Road Bridge Assessment Photo Page 11

27 Photo 23: South Abutment; Note Spalls in Toe Wall Photo 24: Stringer Ends Encased in Concrete, South Abutment (Typical) Bardo Road Bridge Assessment Photo Page 12

28 Photo 25: Hay and Corn Fields in southwest quadrant Photo 26: Storage Barn and House North of Structure; Note Narrow Approach Pavement and Absence of Shoulders Bardo Road Bridge Assessment Photo Page 13

29 Appendix Truck Loading Information

30 The figures below show common truck axle loadings used for analysis of bridges in the state of Pennsylvania. Note the following: One KIP = 1,000 pounds 2,000 pounds = 1 Ton One wheel load = Axle load divided by two The following sheets show the approximate weights of common vehicles.

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