Project Purpose. Project Need

Transcription

1 Project Purpose The purpose of the project is to implement a bridge improvement solution that corrects the existing safety problem at the Strasburg Pike Bridge. The project will provide a structurally sound bridge with adequate roadway and shoulder width over Mill Creek in the SR 2029 network to match the existing roadway cross-section north and south of the existing structure. Project Need The existing bridge, a single-span steel through girder structure, carries Strasburg Pike over Mill Creek. Currently the paved roadway width of the bridge approaches varies between 18 to 20 feet with no shoulders. The bridge is narrow and has no shoulders. The posted speed limit is 35 mph. A reinforced concrete slab culvert carries Strasburg Pike over the millrace immediately south of the creek. The need for improvements is driven by safety deficiencies at the bridge. Safety deficiencies stem largely from the lack of shoulders on the existing structure and the narrow lane width. Currently the roadway width is 18 feet with little to no shoulder. Traffic is forced to come to almost a standstill when two vehicles need to cross the bridge in opposite directions. The statewide accident statistics (2000) suggested that there is a safety concern at the bridge itself, reflective of the narrow structure width. Ten of the reported fifteen accidents in the vicinity of the bridge were hit-fixed object type accidents, versus rearend, sideswipes or head-on accidents. Seven of the fixed objects hits were the bridge itself. The accident history north and south of the bridge were comparatively lower than at the bridge. Additionally, there are deficiencies with the existing bridge s structural soundness. PENNDOT gave the structure a sufficiency rating of 15.6 out of a possible 100 points in their last evaluation. Sufficiency ratings are computed based on the following components: structural adequacy and safety; serviceability and functional obsolescence; and essentiality for public use. The superstructure of the Strasburg Pike Bridge is currently in poor condition and the roadway is narrow. There are no true parapets on the bridge the 18 high barrier on either side of the bridge is substandard. The horizontal geometry adjacent to the bridge includes three horizontal curves with curve radii of approximately 800 feet, 275 feet and 390 feet with minimal superelevation. The corresponding design speeds for these three curves are all less than 20 mph. In addition, the horizontal geometry results in less than adequate sight distance for both vehicles on SR 2029 and for vehicles entering SR 2029 from the adjacent driveways. The stopping sight distance required for a design speed of 35 mph is 250 feet. The existing sight distance for southbound vehicles on SR 2029 is approximately 170 feet with the existing mill creating the sight obstruction. The existing sight distance at two driveways near the existing bridge have sight distances less than 100 feet with either the mill, the existing bridge or existing fences creating the sight obstructions. Hidden Driveway signs are posted along SR 2029 to help warn drivers that vehicles may be exiting these driveways. 1

2 In summary, a structurally sound bridge over Mill Creek with adequate roadway and shoulder width is needed on SR ALTERNATIVES ANALYSIS Build alternatives developed for the bridge replacement project included two off-line alternatives and three on-line alternatives. A No Build option was also included as an Avoidance Alternative and as a baseline for the evaluation of impacts for the build alternatives. This section summarizes the alternatives and design options considered for the Strasburg Pike Bridge Replacement Project. This summary includes the reason for proposing the alternative, a brief description of the alternative, its impact to the Section 4(f) resources, and reasons for retaining it for further study or for dismissing it. 1. Identification and Evaluation of Alternatives that Avoid All Section 4(f) Resources Three Total Avoidance Alternatives were evaluated for this project: a No Build Alternative, and two off-line alternatives. No Build Alternative The No Build is included as an avoidance alternative and as a baseline for the evaluation of impacts for the build alternatives. The No-Build would include work considered as routine maintenance, such as paving, pavement marking and guide rail replacement. Since the No-Build would not impact Section 4(f) resources, it is considered a Total Avoidance Alternative. However, it would not correct the substandard conditions and design deficiencies of the existing roadway and bridge including the poor horizontal geometry and sight distance from surrounding driveways, narrow travel lanes and nonexistent shoulders. Additionally, the structure itself received a sufficiency rating of 15.6 out of 100 during PENNDOT s most recent inspection on July 12, On October 10, 2000, PENNDOT inspected the millrace culvert and rated it at 36.6 out of 100. The No- Build Alternative fails to correct the structural deficiencies of the existing bridge, and fails to meet the project needs; therefore it is not a prudent and feasible alternative. Off-Line Alternatives Off-line alternatives that met the project need included two versions of a bypass to the west of the existing bridge. Both involved construction of a new bridge and roadway beginning approximately 500 feet north of the existing bridge and tying back into Strasburg Pike south of the Binkley House and Mill Complex (Figure 4). Because construction of a new roadway and bridge would require the removal of the existing bridge, these alternatives also incorporate a cul-de-sac south of the Binkley House property to allow access to properties immediately south of the bridge during construction. Both alternatives would result in residential displacements and would impact agricultural land and floodplains. Off-Line Orange Alternative 2

3 The Orange Alternative extended approximately 1,600 feet in a north-south direction. From just north of the bridge, it veered west and closely followed the west side of Mill Creek, tying back into Strasburg Pike approximately 500 feet south of the existing bridge. Three residential and two commercial properties would be displaced by this alternative, as well as 0.73 acres of floodplains and 0.03 acres of agricultural land. Approximately 2.8 acres of right-of-way would be needed for the construction of the Orange Alternative. The estimated construction cost associated with this alternative was $5,000,000. This figure does not include the costs incurred in the purchase and relocation of displaced residential and commercial entities. This alternative was presented to the public at a plans display. Following review by LCPC, PENNDOT and FHWA, the Orange Alternative was dismissed at this time because of the displacements, the impacts to environmental features, and the high cost. Due to these factors, this alternative is not prudent and feasible. Off-Line Purple Alternative The Purple Alternative extended approximately 2,500 feet in a north-south direction. From just north of the bridge, it swung nearly 500 feet west of the existing road and tied back into Strasburg Pike at its intersection with Windy Hill Road almost a half-mile south of the existing bridge. Five residential properties would be displaced by this alternative while 0.49 acres of floodplains and 0.92 acres of agricultural land would be impacted. Approximately 6 acres of right-ofway would be needed for the construction of the Purple Alternative. The estimated construction cost associated with this alternative was $5,400,000. This figure does not include the costs incurred in the purchase and relocation of displaced residences. Although the Purple Alternative is more than 50% longer than the Orange Alternative, the total estimated construction costs appear to be very comparable. However, the roadway construction costs for the Purple Alternative are $700,000 more than those for the Orange Alternative (slightly more than double). The estimated costs for the structures associated with the Orange Alternative are $300,000 more than those for the Purple Alternative due to the greater bridging requirements and retaining walls needed to span a larger portion of the floodplain. 3

4 This alternative was presented to the public at a plans display. Following review by LCPC, PENNDOT and FHWA, the Purple Alternative was not carried forward for further consideration at this time because of the displacements, the impacts to environmental features, and the high cost. Due to these factors, this alternative is not prudent and feasible. 2. Identification and Evaluation of Other Alternatives Considered Because the Binkley House and Mill had previously been identified as eligible for the NRHP prior to the initiation of the project, the on-line alternatives were designed to minimize potential effects to the historic property. Three preliminary on-line alternatives were developed and were presented to PENNDOT at a Safety and Design Review meeting held on February 14, 2001 (Correspondence in Appendix A). On-Line Alternative #1 This on-line alternative widened the bridge and its approaches while essentially maintaining the current roadway alignment. This alternative incorporated design exceptions with narrow lanes (11 ft.) and shoulders (4 ft.) to reduce potential impacts to adjoining properties. This alternative did not include improvements to the roadway north of the structure where two residential driveways currently have limited sight distance when entering SR The flattened curve south of the structure would also have the effect of increasing the speed of traffic. This alternative would require the use of one Section 4(f) property (the NRHP Binkley House and Mill Complex). The pump and well contributing elements to the NRHP eligible Binkley House (Plate 1), will need to be removed to accommodate the new shoulder and retaining wall on the east side of the road. PENNDOT would need to acquire 0.13 acres within the NRHP eligible Binkley House and Mill Complex boundary for this alternative. On-Line Alternative #2 This on-line alternative incorporated design elements from the above alternatives. It extends approximately 1,000 feet along Strasburg Pike (500 feet north and 500 feet south of the bridge) and requires minimal design exceptions (11 ft. travel lanes and 4 ft. shoulders). North of the bridge, the alternative swings slightly to the west straightening the existing horizontal curve while providing increased sight distance from four driveways. South of the bridge, the alignment generally follows the current roadway curving slightly east and provides increased sight distance from two driveways. Of the six driveways where sight distance would be improved, two movements would still have less than the minimum sight distance of 250 feet. This alternative would require the use of one Section 4(f) property (the NHRP Binkley House and Mill Complex). The pump and well contributing elements to 4

5 the NRHP eligible Binkley House (Plate 1), will need to be removed to accommodate the new shoulder and retaining wall on the east side of the road. PENNDOT would need to acquire 0.13 acres within the NRHP eligible Binkley House and Mill Complex boundary for this alternative. On-Line Alternative #3 This on-line alternative combined a widening and a straightening of the roadway while providing increased sight distance from four driveways intersections north and south of the bridge. This alternative included standard lane (12 ft.) and shoulder (8-10 ft.) widths. The southbound shoulder width was proposed to be 10 feet near the mill to increase the southbound stopping sight distance at the mill to the minimum 250 feet. This alternative would require the use of one Section 4(f) property (the NHRP Binkley House and Mill Complex). The pump and well contributing elements to the NRHP eligible Binkley House (Plate 1), will need to be removed to accommodate the new shoulder and retaining wall on the east side of the road. PENNDOT would need to acquire 0.25 acres within the NRHP eligible Binkley House and Mill Complex boundary for this alternative. The use of the pump and well in front of the Binkley House are common to all the on-line alternatives. PENNDOT would need to acquire 0.13 acres within the NRHP eligible Binkley House and Mill Complex boundary for On-Line Alternatives #1, and #2. On- Line Alternative #3 requires the use of the most land area from the Section 4(f) resource almost twice that of the other on-line alternatives. Therefore, On-Line Alternatives #1 and #2 would have similar impacts on the Section 4(f) resource, while On-Line Alternative #3 would use more land area from the resource. On-Line Green Alternative Following the Safety and Design Review, PENNDOT indicated their preference for On-Line Alternative #2, but with slight modifications. This alternative would require the use of 0.24 acres of floodplains and one Section 4(f) property: the NRHP Binkley House and Mill Complex. No displacements or agricultural impacts would occur. Land areas from the east and west sides of Strasburg Pike would be required for the design of the bridge replacement. Increasing roadway and shoulder widths and straightening the curved roadway will require 0.86 acres of total right-of-way for the construction of the Green Alternative. Of the 0.86 acres, PENNDOT would need to acquire 0.13 acres within the NRHP eligible Binkley House and Mill Complex boundary for the On- Line Green Alternative. The pump and well, and landscape features including shrubbery on the east side of Strasburg Pike in front of the Binkley House, would need to be removed to 5

6 accommodate a new shoulder and retaining wall on the east side of the road. The pump a contributing element to the NRHP eligible resource, will be replaced after construction on a new concrete pad. The PA SHPO was consulted in this decision. A temporary detour would be necessary during construction due to the closure of the existing bridge. The 5.5-mile detour would use all local roads and would require no improvements. The On-Line Green Alternative was presented to the public at a plans display held on May 31, Following review by LCPC, PENNDOT and FHWA, it was carried forward for further consideration because it meets the project needs, requires no displacements, and has fewer impacts to floodplains and agricultural land than the off-line alternatives. It requires 0.86 acres of total right-of-way versus 3.0 acres and 6.0 acres for the Off-Line Orange Alternative and the Off- Line Purple Alternatives, respectively. The On-Line Green Alternative, at an anticipated cost of $950,000, will have a much lower construction cost than the off-line alternatives because of its shorter roadway length. Because of these factors, this alternative is prudent and feasible. A summary of the alternatives is included in Table 1. CONCLUSION Based upon the above considerations, there is no prudent and feasible alternative that would avoid the use of land from the NRHP eligible Binkley House and Mill Complex. The proposed On-Line Green Alternative is a prudent and feasible alternative with the least harm to Section 4(f) resources. 6