Preserva on Assessment

Transcription

1 Preserva on Assessment For Ftorkowski Road Bridge over Hun ngton Creek BMS # Luzerne County PennDOT Engineering District 4 0 Final Report June 2016 Prepared by TranSystems for the Pennsylvania Department of Transporta on Environmental Policy and Development Sec on

2 BRIDGE LOCATION N BRIDGE LOCATION MAP Ftorkowski Road (T-482 ) over Huntington Creek Huntington Township, Luzerne County, PA Source: PA Type 10 Map; Luzerne County

3 RESOURCE LOCATION QUADRANGLE LOCATION SCALE SOURCE 0ft 2000ft USGS 1954 Shickshinny, PA N Ftorkowski Road (T-482 ) over Huntington Creek Huntington Township, Luzerne 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: 4-0 County: Luzerne Township: Huntington Owner: Luzerne County Maintenance: Luzerne County Location Information: North of Harveyville Road NE of Harveyville. Bridge Name: Ftorkowski Road (T-482) over Huntington Creek Type: Pony Truss Design: Pratt (Pinned) Truss Materials: Wrought Iron Date: CA 1889 Alter/Rehab: Yes; Dates Unknown Source: Plaque Length: 78' Number Spans: 1 Deck Width: 15-8 (curb-to-curb dimension) Bridge Description The one span, 78'-long, wrought iron, pin-connected, Pratt pony truss bridge was built by Dean & Westbrook using Phoenix sections for the upper chords and inclined end posts and standard design Phoenix Company connecting pieces and bearings along with details that are particular to Dean & Westbrook. The roadway width is This is not a standardized design Pratt pony truss bridge, and it represents Dean & Westbrook s innovative thinking about features intended to provide a stronger bridge with the most economical use of material. The verticals are composed of angles with Ftorkowski Road Bridge Assessment Page 1

5 lacing. Pin plates are used to make their connection at the cast iron upper chord connecting pieces. The deep, built up floorbeams are framed into the bottom portion of the verticals above the eyebar lower chords. There are punched pin holes in each vertical for the lower panel point connection. Placing floorbeams above the lower chords is not common in Pratt pony truss bridges. A triangular-shaped plate riveted to both ends of each floorbeam accommodates connection of an outrigger that meets the vertical at about its midpoint. The diagonals are eyebars, and the counters are bar stock with Dean & Westbrook s cast open loop heads. The bridge is finished with two lines of pipe railings set in their original cast iron socket fittings and a wood plank deck. It is supported on stone abutments with concrete repairs. NR Eligibility Status: Eligible (SHPO Finding 3/1988) under Criterion C for technological significance. Historic Preservation Priority: Exceptional (see Protocols for Levels of Priority located at insert hyperlink to Appendix 2 in the Management Plan Document). Historic Preservation Priority Justification: Of the several remaining examples of this Dean & Westbrook designed and fabricated Pratt pony truss bridge with the floorbeams above the lower chords, this example is the most historically and technologically significant. The makers plaque documents it to 1889, and it served as the prototype for the other examples, which have variations of the details of this bridge. Dean & Westbrook were the agents marketing and building highway bridges for the Phoenix Iron Company and using Phoenix sections. The company is noted for innovative designs, including at least five remaining examples of this one in Luzerne and Chester ( ) counties and the English Center (Lycoming County) hybrid design placed in The bridge has high technological significance because of its distinctive details (such as the floorbeam connection, outrigger detail and pin plate connection of the top chord to verticals). representing the era of experimentation in metal truss bridge design and the use of Phoenix sections, which did as much as any detail to prove the value of metal truss bridges during the last half of the 19 th century. The cast- and wrought-iron bridge provides an important snapshot of thinking about bridge design and fabrication prior to steel and standardization. All bridges with Phoenix sections have cultural value. The character-defining features include the truss form and method of truss member end connection (pinned Pratt Pony truss), the Phoenix section truss members, the truss to floorbeam connection details (floorbeams framed into the bottom portion of the verticals above the eyebar lower chords and punched pin holes in each vertical for the lower panel point connection) and the outrigger detail (outrigger meets the vertical at about its midpoint). The bridge plaque and bridge railings are also considered significant features. Ftorkowski Road Bridge Assessment Page 2

6 Roadway & Site Information Setting Description: The bridge is located on a one lane unimproved road in a rural setting with woodlands, active agriculture and scattered houses. There is an early 19 th century house beyond the bridge. The 15-8 wide bridge roadway is as wide if not wider than the maintained travelway. The bridge and road have a very low reported traffic volume. Type of Bridge Service: One lane (less than 18'-wide travelway) serving twodirectional traffic. Bridge Roadway Width: 15-8 face-to-face bridge railing. Approach Travelway Width: 13'± Vertical Clearance: N/A. Functional Classification: Rural Local ADT(2014): The ADT is listed as 55. The source of the BMS traffic count on the bridge is not known. This is an estimate and represents the conventional entry for low volume local roads in Luzerne County. 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 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 those bridges in service. Shoulders/Sidewalks: None. Observed Crash History: Minor impact damage was observed to the bridge railing at the south east corner. 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 an isolated incident, and is not indicative of a continual problem. Safety Features: Pipe railing with several bent sections on the south truss and a missing lower rail element on the north truss. Proximity of Alternate Routes: To reach the south side of the bridge on Ftorkowski Road, there are two alternate routes available. To the east, the alternate route is 4.7 miles long using SR 4015, SR 4024, T-671, T-494, SR 4019 and SR 4016 to bypass 0.5 miles on Ftorkowski Road. To the west, the alternate route is 0.6 miles long on SR 4015 and SR 4016 would be traveled to bypass 0.5 miles on Ftorkowski Road. Neither Ftorkowski Road Bridge Assessment Page 3

7 route has bridges with height or weight restrictions. The actual alternate route 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 adequate connectivity. Summary Geometric Deficiencies: With a bridge roadway width of 15-8, the bridge is classified as functionally obsolete because it does not meet the 18' definition of a two lane facility. The road is also a one lane facility. The sight distances appear to be adequate. Performance Summary: While it does not meet current design requirements, there is minimal evidence of a crash history and therefore it appears that the bridge is operating in a safe manner for those vehicles permitted to use the bridge. Hydraulics: Huntington Creek flows north to south. Banks are stable and well vegetated with trees. Rock protection has been placed along the west bank. There is a slight risk of overtopping as per BMS2. BMS Condition & Load Sufficiency Condition Code Ratings (2014) Superstructure: 4 Poor Substructure: 4 Poor Deck: 4 - Poor Controlling Load Ratings Inventory: 3T Operating: 3T Method: Load Factor (Floorbeams & Stringers) Allowable Stress (Truss) Engineering Judgment (Substructure) Posted? Yes (3 tons). LOAD FACTOR METHOD (unless noted otherwise) STRUCTURAL MEMBERS H-20 (20 Tons) HS-20 (36 Tons) ML-80 (37.74 Tons) TK-527 (45 Tons) STRINGERS (inv.) 7* 13* 11* 14* STRINGERS (opr.) 12* 22* 18* 23* (1) FLOORBEAM (inv.) 13* 23* 18* 22* (1) FLOORBEAM (opr.) * 36* (2) TRUSSES U2L3 (inv.) 16* 23* 18* 22* (2) TRUSSES U2L3 (opr.) 25 32* 28* 32* (3) SUBSTRUCTURE (inv.) 3* 3* 3* 3* (3) SUBSTRUCTURE (opr.) 3* 3* 3* 3* (1) Controlling Members (in red) (2) Allowable Stress Method (3) Engineering Judgment (*) indicates insufficient capacity for given truck Ftorkowski Road Bridge Assessment Page 4

8 The latest analysis is from The bridge has been posted for a weight restriction of 3 tons based on the condition of the substructure units since 12/09/86. The stringers control the rating of the superstructure with a H20 capacity of 7 tons at inventory rating level and 12 tons at operating rating level. The controlling truss member is U2L3 with a posting of 16 tons at inventory stress levels. 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. For schematics showing the axle loads of typical PennDOT vehicles used for live load ratings, see Appendix. Summary Structural Deficiencies The structure is rated in overall serious (3) condition due to the condition of the substructure. Based on BMS2 data, confirmed by a cursory field view, the following specific deficiencies were observed. Refer to photographs for additional details. Truss Lines There is section loss (4 x1 area of 100% section loss) at the lower portion of all inclined end posts (on one segment of the Phoenix section). The truss members have peeling/flaking paint with pitted and rusting wrought iron. One lower chord eyebar is bowed. A few diagonals are slightly loose or bowed. Bearings The bearings are buried in debris with peeling paint, pitting, and minor rust. Floorbeams There is moderate corrosion on the floorbeams, especially at the bottom flange, with slightly peeling/flaking paint. Stringers The stringers also have light to moderate corrosion, with slightly peeling/flaking paint. The stringers control the load capacity ratings for superstructure. Substructure The condition of the stone abutments is rated as poor because of missing stones, cracks, movement and failing concrete repairs. Portions of each abutment have already been repaired / rebuilt with concrete. The east abutment is more deteriorated than the Ftorkowski Road Bridge Assessment Page 5

9 west one with a full height crack indicative of settlement. Concrete sections where prior repairs have occurred are lightly cracked. Masonry portions show some mortar deteriorations. The previously repaired stone abutments are in poor condition with open and cracked joints. The far abutment has a full-height crack, missing stones and displacement in one wingwall. Deck Transverse timber planks are weathered and have checks/splits. Several planks are warped up at the ends and there are a few bent/exposed nails. Timber nailers have checks and splits. Rehabilitation & Preservation Considerations Benchmark for Assessing Rehabilitation The existing bridge has an exceptional historic preservation priority and is located on a very low volume local road with an extremely low reported volume of traffic. There are nearby alternate routes 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 adequate could be undertaken. The bridge has structural deficiencies related to capacity of some flooring system members, corrosion of the several truss members, peeling/flaking paint and deteriorated abutments. There are conventional treatments to correct the deficiencies to increase its load carrying capacity, reduce its inspection cycle, and conserve the historic bridge for long-term service and preservation. The deficiency that will require the most sophisticated repair technique is addressing the holes in the Phoenix section inclined posts, but work in the past 15 years on conserving other truss bridges with Phoenix sections and increased understanding of welding wrought iron can be used to inform a cost-effective strategy. 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 of the superstructure and deterioration of the substructure. Traditional treatments for improving load carrying capacity based on the capacity of the trusses are considered. There is also a body of empirical work related to conserving Phoenix sections that can be applied to considering the effectiveness of making needed repairs. This analysis is based on considering options that make the bridge structurally adequate 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. Ftorkowski Road Bridge Assessment Page 6

10 Maintenance The nature of the work needed to address the several structural superstructure and substructure deficiencies could be considered maintenance work. They include addressing the deteriorated condition of the stone abutments and addressing the holes in the inclined end posts, one bowed eyebar, and cleaning and painting the bridge. It also includes cleaning debris from the bearing, addressing corrosion on flooring system components, replacing the deteriorated timber plank deck, and placing appropriate safety features like guide rail at the approaches. If the bridge were to be repaired and repainted, there are conventional and cost effective treatments that should be performed on a routine basis in order to 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, including repairs to the Phoenix section. 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. The deteriorated sections or the entire members of the flooring system require in kind repair or replacement. This can be done in a manner that does not have an adverse effect as long as the floorbeam connection details to the truss are maintained. There are several approaches to repairing corroded Phoenix sections that can be evaluated to determine the most appropriate and cost effective way to address the holes in the columns just above each bearing such as removing a portion of the Phoenix section and replacing with a pipe section of similar diameter with welded fins reading as the channel flanges. Truss expansion bearings will be replaced with neoprene or polytetrafluoroethylene (PTFE, better known as Teflon ) bearings while the fixed bearings will be cleaned and repainted. The stone abutments also need to be repaired to address the cracks, failed mortar joints, missing stones, and deteriorated seats. Repair to the substructure units or replacement of the existing substructure unit with concrete abutments, will not adversely affect the historic significance and cultural value of the bridge, as it is not considered a character defining feature of the bridge. The appropriate placement of safety features to protect motorists and the truss lines is also permissible. The original bridge railings should be retained and the new railings should not be attached to the truss. It may be efficient to lift the truss from its seats in order to repair or reconstruct the abutment(s) in order to allow Ftorkowski Road Bridge Assessment Page 7

11 easier access to the work and avoid costly stream regulations and restrictions. The cost of structural repairs to the trusses and cleaning and painting should be estimated with the bridge on the ground rather than over the stream. 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 adequate 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, 4 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. $15,000 Temporarily Remove & Reset Truss L.S. $35,000 Construct New Substructure Units 150 $1,500 $225,000 Stone Facing 1,000 SF x $15/SF $15,000 Truss Repairs $15,000 $60,000 Truss Bearings $10,000 $20,000 Clean & Paint Superstructure L.S. $150,000 New Stringers 6 x 78 x 30# = 14,040 LB x $3.50 $49,140 New Timber Deck 1,225 SF x $20 $24,500 Bridge Railing 156 x $75 $11,700 Approach Guiderail 300 x $50 $15,000 Subtotal: $620,340 20% $124,068 TOTAL: $744,408 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 estimate. The cost does not include engineering, mobilization, maintenance and protection of traffic, erosion control measures, etc. Ftorkowski Road Bridge Assessment Page 8

12 Flushing Truss/Bearing Area $1,000/YR 30 ($ ave.) $51,405 Timber Deck Repairs 10, 20 & 30 years $13,943 $3,360 + $4,515 +$ 6,068 Spot Cleaning & Painting 15 & 30 years $39,850 $15,580 + $24,270 TOTAL: $105, $43,345 The cost model yields a total rehabilitation program in present dollars equal to $800,000. The cost for a bridge replacement is estimated to be approximately to $1,200,000 based on similar statewide projects. The cost does not include engineering, mobilization, maintenance and protection of traffic, erosion control measures, etc. Other Reasonable Options For Reuse This is a low volume local crossing, and there are adequate alternate routes 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. Because the bridge is accessible and the span length is relatively short, it is possible to lift the bridge and transport it. 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 Ftorkowski Road Bridge could be rehabilitated to carry 15 tons without altering its character defining Ftorkowski Road Bridge Assessment Page 9

13 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 a crossing is not required at this location or if construction of a new bridge is required at the crossing based on project needs, then 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 nonvehicular use. Ftorkowski Road Bridge Assessment Page 10

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16 15' HOUSE ' DETERIORATED ' 13' BITUMINOUS PAVEMENT CONCRETE WINGWALL 16' TIMBER DECK WEST OUT TO OUT FLOW 75' HUNTINGTON CREEK FLOW 34' CONCRETE WINGWALL EAST 11' STONE MASONRY WINGWALL 6 AERIAL UTILITY POLE NO FTORKOWSKI ROAD (GRAVEL) LEGEND X PHOTO NUMBER AND DIRECTION TITLE NTS FTORKOWSKI ROAD

17 Photo 1 North Elevation Photo 2 West Approach Looking East Ftorkowski Road Bridge Assessment Photo Page 1

18 Photo 3 East Approach Looking East Photo 4 South Truss with Bridge Railing Ftorkowski Road Bridge Assessment Photo Page 2

19 Photo 5 North Truss and Deck Photo 6 General View of Deck Looking West Ftorkowski Road Bridge Assessment Photo Page 3

20 Photo 7 Truss Upper Chord Connection Photo 8 Truss Vertical and Inclined End Post Ftorkowski Road Bridge Assessment Photo Page 4

21 Photo 9 Bridge Railing Connection to Inclined Post Photo 10 Truss Upper Chord Ftorkowski Road Bridge Assessment Photo Page 5

22 Photo 11 Truss Lower Chord Photo 12 Floorbeam Connection detail Ftorkowski Road Bridge Assessment Photo Page 6

23 Photo 13 East Abutment Photo 14 West Abutment Ftorkowski Road Bridge Assessment Photo Page 7

24 Appendix Truck Loading Information

25 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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