DRAFT PATTULLO BRIDGE ALIGNMENT ASSESSMENT OCTOBER 2011 SW1146SWU

Transcription

1 DRAFT PATTULLO BRIDGE ALIGNMENT ASSESSMENT OCTOBER 2011 SW1146SWU

2 TABLE OF CONTENTS SECTION 1 INTRODUCTION Objectives Background... 1 SECTION 2 ALIGNMENT OPTIONS... 4 SECTION 3 ASSESSMENT FRAMEWORK & METHODOLOGY Financial Customer Service Other Criteria... 8 SECTION 4 ALIGNMENT OPTION ASSESSMENT Financial Customer Service Other Criteria Summary i Pattullo Bridge Alignment Assessment

3 SECTION 1 INTRODUCTION As part of the decision to replace the existing Pattullo Bridge, there is a need to identify the preferred alignment for the new bridge across the Fraser River, the level of connectivity to the existing road networks in the adjoining municipalities, and the number of bridge lanes required to safely provide sufficient mobility for the forecasted travel demand. This document summarizes the assessment of the two key alignment alternatives identified in the previous study, with the evaluation of the connectivity and number of bridge lanes to follow in subsequent reports. 1.1 OBJECTIVES With the objectives of the previous study being primarily related to identifying the need to replace the existing bridge or retain the existing bridge, a full investigation of the bridge alignments and connection options was not warranted. However, the primary objective of this assessment is to identify the preferred alignment, from the two short listed options. Other key objectives of this alignment assessment study are: Conduct a high level financial assessment of the benefits and costs of the replacement options Develop appropriate criteria to assess the bridge alignment options to assist in identifying a preferred alignment with less impacts and potentially higher benefits. Document the results of the assessment in a brief summary report. 1.2 BACKGROUND In the previous Pattullo Corridor Study (Delcan / TransLink - May, 2008), two alignment options were retained for further consideration. The preferred of these two alignments was identified as Alignment 3 and is located downstream of the existing Pattullo Bridge with an offset of approximately 50 metres to avoid impacts to the existing river structures during construction. The other retained option, previously identified as Alignment 1, is located upstream of the rail bridge, with an offset of approximately 50 metres, again to avoid impacts to the existing river structures. Both of these alignments were assumed to be parallel to the existing bridges as shown in Figure 1. 2 Pattullo Bridge Alignment Assessment

4 Figure 1 Recent transportation planning work conducted in 2011 and related to the North Fraser Perimeter Road in New Westminster resulted in a decision to not to construct the United Boulevard Extension due in large part to the lack of support in the local community. In not constructing this vital link in the North Fraser Perimeter Road west corridor, this decision has placed the entire west corridor upgrade in jeopardy. As such, a previous recommendation from the Pattullo Corridor Study to connect the new Pattullo Bridge to the North Fraser Perimeter Road at the Front Street segment is no longer valid. Without the proposed upgrades to the entire North Fraser Perimeter Road corridor, connections to the Front Street corridor are impractical. Therefore, any connections to the new Pattullo Bridge on the north side of the river will remain as per the current conditions with the primary connection remaining along McBride Boulevard and the secondary connections to Royal Avenue and Columbia Street East, both Major Road Network Elements. The exact configuration of these connections to the Major Road Network elements on the north end of the new bridge will be investigated in later stages of the functional planning for the new bridge. On the south side of the river, the previous assumptions to provide the primary connections between the new bridge and King George Boulevard remain valid as no changes to the transportation network on the south side of the river have taken place to supersede the previous assumptions. Secondary connectivity to Scott Road and possibly to the South Fraser Perimeter Road (under construction) also remain valid and will be explored in more detail in subsequent reports. 3 Pattullo Bridge Alignment Assessment

5 SECTION 2 ALIGNMENT OPTIONS The Pattullo Corridor Study recommended that the new replacement bridge alignment be retained in the existing corridor. However, the level of analysis of this previous study could not accurately differentiate between a parallel upstream alignment and a parallel downstream alignment. Further work was subsequently undertaken in this study to examine the two alignment options in more detail and to determine the preferred alignment. Alignment Refinement Building upon the planning level findings from the previous study, the alignment of the new bridge is also determined by the level of connectivity to the municipal road networks and the likely bridge types and the associated span arrangement that are the most practical for this section of the Fraser River given the navigational channel requirements, river hydraulics, geotechnical, and environmental constraints. Together, these three aspects of the new bridge (alignment, connectivity, and bridge type / span arrangement) will need to be combined and evaluated together to accurately define the new bridge alignment. However, the analysis of the level of connectivity and specifically the connection configurations and related property impacts at either end of the new bridge is deferred to further studies which will be undertaken in later stages of the functional planning activities. Therefore, to allow for future modifications or refinements to the two alignment options, an alignment band for each option has been developed. The width of the bands depend upon a number of further assumptions including the retention of the primary connection to McBride Boulevard and the secondary connections to Royal Avenue (to / from the west) and Columbia Street (to / from the east) on the north side. How and where these connections between the new bridge and Major Road Network occur represents some level of variability in the actual bridge alignment. Furthermore, connections to McBride Boulevard involve two potential corridors on either side of the existing residential island located south of Royal Avenue, between McBride Boulevard and the approach to the existing bridge. These additional alignment variations are represented in the two alignment options as described below and shown in Figure 2: 4 Pattullo Bridge Alignment Assessment

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7 DOWNSTREAM ALIGNMENT This alignment is located approximately 50 metres downstream from the existing Pattullo Bridge. This alignment remains parallel to the existing bridge as this represents the most efficient roadway geometry due to the need to tie back into the main roadway corridors on the north and south side of the Fraser River. Due to the required roadway geometry to provide connectivity between the downstream alignment and the existing McBride Corridor, this alignment logically follows the approach to the existing bridge located on the west side of the residential island. This alignment represents Alignment 3 from the previous study. UPSTREAM ALIGNMENT This alignment is located approximately 50 metres upstream from the existing New Westminster Rail Bridge. As noted above in Section 1, this alignment represents Alignment 1 from the previous study. Two variations of this upstream alignment were developed to examine alternate means of connecting to the McBride Boulevard corridor. The first alternative includes a connection to the McBride Boulevard corridor west of the residential neighbourhood island and largely following the approach or connection to the existing Pattullo Bridge. Conversely, the second alternative includes a connection to the McBride Boulevard corridor east of the residential neighbourhood island, in the existing right-of-way of the local segment of McBride Boulevard. The connection to the King George Boulevard corridor is similar between the two upstream alignment variations with the actual connection being offset slightly to the east of the existing south bridge (approach structure) abutment. 5 Pattullo Bridge Alignment Assessment

8 SECTION 3 ASSESSMENT FRAMEWORK & METHODOLOGY Two alignment options, downstream and upstream, have been identified as candidates for the preferred alignment for the new Pattullo Bridge. The following section provides a high level comparative assessment of these two alignments using a set of the evaluation criteria previously derived and applied in both the Pattullo Corridor and the Pattullo Bridge Option Assessment studies. However, due to the high level nature of this assessment, only a subset of the previous criteria was used in this assessment with a focus on those criteria providing a clear difference between the options being assessed. The evaluation criteria are presented in three categories: Financial, Customer Service, and Other. A brief description of each of these categories is provided below. 3.1 FINANCIAL Four sub criteria are included under the financial evaluation category: capital cost; salvage value; property cost, and maintenance costs. Where applicable, an analysis period of 25 years has been applied and present value (PV) costs in 2011 dollars were generated by summing the costs over this analysis period. CAPITAL COSTS The capital costs evaluation represents the planning level / class C cost estimates using the elemental parametric cost estimating methodology. In addition to actual construction costs, these project cost estimates include values for future planning, design, project management, construction administration, and contingencies. SALVAGE COSTS The salvage value accounts for project elements that have not yet reached their full life at the end of the planning horizon / life cycle, and it is based on the initial cost, the service life, and the remaining life of the facility. The salvage value has been calculated with respect to the facility components within the jurisdiction of TransLink (e.g. key bridge structural elements). 6 Pattullo Bridge Alignment Assessment

9 PROPERTY Based on the conceptual design drawings prepared in the previous studies, a number of property impacts were identified for each alignment option. Costs have been estimated based on the full and partial takes of the property impacted, recognizing industrial, residential, and other land uses. These cost estimates include contingencies to account for expropriation settlements and business losses. MAINTENANCE Maintenance cost estimates for the TransLink facility components have been applied to the alignments options over the entire planning / analysis period, such as all of the key structural components situated between the bridge abutments. 3.2 CUSTOMER SERVICE The Customer Service category consists of quantitative indicators which include travel time savings, vehicle operating savings, and traffic safety. Based on these indicators, user benefit / cost ratios are generated for each alignment option. TRAVEL TIME SAVINGS Travel time savings estimates are based on outputs from a version of the regional travel demand forecasting model, namely the Gateway Sub Area Model State 4 with the GMS 5.0 Draft 2 revised land use. The AM and PM peak hour output has been expanded to estimate annual travel time savings. The estimates, which include value of time, are calculated by summing the travel time savings over the entire analysis period assuming constant savings throughout. For the purposes of this study, travel time savings were calculated against a base case where the existing bridge would be rehabilitated and operated as a three lane bridge with a reversible centre lane as per the findings in the Pattullo Bridge Option Assessment Study (Delcan 2011). 7 Pattullo Bridge Alignment Assessment

10 VEHICLE OPERATING COSTS Vehicle operating cost estimates are based on the vehicle kilometres travelled output from the travel demand forecasting models. The output from the AM and PM peak hours has been expanded to estimate annual vehicle operating costs. These estimates include an average operating cost per kilometre and a summation of vehicle operating costs over the entire analysis period. TRAFFIC SAFETY IMPROVEMENTS Traffic safety is quantified by summing collision costs over the analysis period of 25 years. The expected number of collisions per annum was estimated using collision prediction models, collision rates, and collision modification factors where applicable. The evaluation considers only incremental differences (Δ) between the key alignment options rather than relative to the base case (which has not been estimated). It is anticipated that the difference between the base case and the two alignment options would be higher than the incremental difference between the two alignment options. Therefore, the current methodology is considered conservative. 3.3 OTHER CRITERIA Other criteria included in the assessment include pedestrian and cyclist accommodation, vehicle connections to the Major Road Network, property impacts, river navigation, and environmental impacts. PEDESTRIAN AND CYCLIST ACCOMMODATION The provision of appropriate pedestrian / cycling facilities on the bridge and the level of connectivity to the existing pedestrian and cycling facility network on both sides of the river has been evaluated qualitatively. The evaluation includes factors such as increased travel lengths, circuitous routing, and grades. VEHICLE CONNECTIONS TO THE MAJOR ROAD NETWORK (MRN) The vehicle connections to the MRN are evaluated based on the complexity of the connection which in turn relates to operational issues, property impacts, and construction costs. 8 Pattullo Bridge Alignment Assessment

11 PROPERTY IMPACTS Property impacts are estimated by the number of property takings associated with each alignment option. Reasonable estimates have been made in terms of the number of actual properties impacted. Though the impacts have been further categorized in previous studies, only an aggregation of the number of takings is presented due to the lack of detail being considered in this study with respect to the configurations of the various connections. RIVER NAVIGATION Improvements to navigation along the Fraser River have been evaluated qualitatively by comparing the achieved navigational clearance (vertical and horizontal) for each of the options. This evaluation is based on a high level assessment of bridge types and span arrangements (pier locations). ENVIRONMENTAL IMPACTS The environmental impacts include three sub categories: terrestrial impacts, aquatic impacts, and archaeological impacts. The two alignment options have been ranked according to low, moderate, or high impact ratings on terrestrial and aquatic features; and a relative ranking of higher or lower impacts on archaeological features. 9 Pattullo Bridge Alignment Assessment

12 SECTION 4 ALIGNMENT OPTION ASSESSMENT Each of the two alignment options has been assessed against the various criteria and the results are presented in Table 1. It is noted that the results are primarily based on those presented in the Pattullo Corridor Study and the Pattullo Bridge Option Assessment Study. Table 1 Evaluation Results for the Downstream and Upstream Alignments CRITERIA FINANCIAL UNIT DOWNSTREAM UPSTREAM Alignment 1 Alignment 3 Capital Cost - Facility $M Salvage Value $M Property $M Maintenance and Operations $M Total Cost (PV) $M CUSTOMER SERVICE Travel Time Savings $M Vehicle Operating Savings $M Traffic Safety (Δ) $M 0 7 Benefit / Cost (B/C) OTHER Pedestrian & Cyclist Accommodation Vehicle Connections to MRN Property Impacts (displacement) Significant Improvement over existing conditions More complex connectin to MRN on thenorth side of the river 7 in New Westminster 9 in Surrey Two parks impacted directly Significant Improvement over existing conditions Less compex connection to MRN at the north approach to the bridge 7 in New Westminster 9 in Surrey No parks impacted River Navigation Moderate Improvement Moderate Improvement Environmental Impact Low to potentially moderate impact on terrestrial (vegetation, wildlife) Moderate impact on aquatic (vegetation, fish, wildlife) Lower anticipated archaeological impacts Low impact on terrestrial (vegetation, wildlife) Low to moderate impact on aquatic (vegetation, fish, wildlife) Higher anticipated archaeological impacts 10 Pattullo Bridge Alignment Assessment

13 4.1 FINANCIAL As can be seen from Table 1 under the financial category, the total cost of the downstream alignment option is higher than that of the upstream alignment option by a magnitude of approximately $46 million (PV). The total cost includes the capital cost, salvage value, property cost, maintenance and operational costs. From the information presented in the Pattullo Bridge Option Assessment Study, a Base Case was identified which consisted of a rehabilitated three lane bridge with a centre reversible lane with a total cost of approximately $139 million (PV). For comparative assessment purposes, the total cost of this Base Case reversible lane option can be discounted from the implementation costs for the two alignment options to achieve the incremental cost for each option. The incremental costs for the two options are summarized below: Downstream Alignment Upstream Alignment $455 Million $409 Million 4.2 CUSTOMER SERVICE Several criteria were evaluated under the customer service category including travel time savings, vehicle operating savings, and traffic safety. Incremental Benefit to Cost ratios were then generated for each of the two alignment options. Based on the results presented in Table 1, the two alignment options show identical travel time savings and vehicle operating costs with a minor difference in the traffic safety improvements. The similarity in travel time and vehicle operating cost savings is due to the fact that both the downstream and upstream options were assessed using the same alignment in the travel demand forecasting model. The slight difference in the location of the two alignments would not result in significant travel time differences given the level of accuracy involved in using the macro level travel demand forecasting model. This information was extracted from that presented previously in the Pattullo Bridge Option Assessment Study. Similar to the total cost under the financial category, the travel time and vehicle operating savings for the Base Case has been discounted from the benefits estimated for each of the two alignment option. The travel time savings, vehicle operating savings, and traffic safety measures altogether yield total benefits of $448 Million for the downstream alignment and $455 million for the upstream alignment. 11 Pattullo Bridge Alignment Assessment

14 The resulting benefits to cost ratios (B/C) for the downstream and upstream options were estimated to be 0.98 and 1.11, respectively. Based on this benefit to cost ratio analysis, the upstream option is performs slightly better financially when compared to the downstream option. 4.3 OTHER CRITERIA This category includes a number of qualitative evaluation criteria: pedestrian and cyclist accommodation, vehicle connections to the Major Road Network, property impacts, river navigation, and environmental impacts. As depicted in Table 1, both the downstream and upstream option are considered to provide significant improvements in pedestrian and cyclist accommodation, similar impacts in the number of properties affected, as well as moderate improvement in river navigation (based on the proposed pier placement associated with a cable stay bridge with a main span of 350 metres see Figure 3). A summary of the assessment of each option with respect to these criteria is provided below: PEDESTRIAN AND CYCLING ACCOMMODATION For the purposes of this study, one way pedestrian / cycling facilities have been assumed to be located on both sides of the new bridge. In both alignment options, the connections to the existing cycling network on the north and south side of the river would be similar in that direct connections to the BC Parkway (south side) and the Central Valley Greenway along Columbia Street remain the primary objective. In both options, connections to the BC Parkway in New Westminster and the Brunette Fraser Greenway would be provided indirectly via the Central Valley Greenway. VEHICLE CONNECTIVITY TO MAJOR ROAD NETWORK With regards to the vehicle connections to the major road network, the upstream alignment has somewhat less complex connections to the MRN whereas the downstream option has more complex connections which also lead to higher construction costs. In the downstream alignment, the further offset of the bridge alignment downstream of the existing bridge alignment results in the required geometry for the roadways connecting to the existing road network to be more constrained and thus complex. It is anticipated that connections to the road network in New Westminster and Surrey for the upstream alignment will be more direct. 12 Pattullo Bridge Alignment Assessment

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16 PROPERTY IMPACTS Based on the assessments conducted in the previous reports and assuming similar levels of connectivity to the identified Major Road Network elements, a similar number of properties are impacted in both alignment options. However, downstream alignment affects park land (Brownsville Bar Park) on the south side of the river and potentially some park land (Albert Crescent Park) on the north side of the river depending upon the final configuration of the bridge connections. The upstream alignment is anticipated to have minimal to no impacts on any park land. RIVER NAVIGATION Additional analysis was conducted to identify areas where the placement of additional bridge piers in the river would potentially result in river bed scour issues. These scour issues, if significant, could potentially affect the stability of the foundations for the two existing bridges. To this end, a number of no pier zones were identified as shown on Figure 3. Also, further analysis was conducted to identify the navigation channels for this section of the Fraser River. Through discussions with Navigable Waters Protection Division (Transport Canada), Port Metro Vancouver, and the Council of Marine Carriers, a primary / deep sea channel 225 metres wide and 45 metres in height (vertical clearance) was identified along with a secondary / domestic channel of 60 metres. These channels are also shown on Figure 3. Assuming a 350 metre cable stay bridge in both alignments, the approximate location of the main bridge piers have been located on these two figures. As can be seen, in both alignments, placement of the bridge piers avoids the no pier zones and thus the associated river bed scour issues. The bridge pier locations also span the two navigation channels, therefore avoiding any impacts to future river navigation. With the removal of the existing Pattullo Bridge, the number of piers in the Fraser River will be less than today. 13 Pattullo Bridge Alignment Assessment

17 ENVIRONMENTAL EFFECTS In terms of the environmental category, most of the assessed criteria for the two alignment options have similar rankings that range from low to moderate. A brief summary is provided below: Downstream Alignment: Terrestrial Impacts Vegetation: New Westminster connections will affect bluff and park vegetation; significant impacts to heritage chestnut tree between Wellington Street and Columbia Street may not be avoidable due to alignment. Low to Potentially Moderate Impacts Terrestrial Impacts Wildlife / Habitat: Limited wildlife habitat capability / suitability associated with bluff and park vegetation. Low Impacts Aquatic Impacts Vegetation: Potential for bridge pier on Surrey shoreline would affect riparian vegetation. Potential for bridge pier on New Westminster shoreline would affect limited riparian vegetation. Connection to King George Highway will displace Pattullo Channel riparian vegetation. Moderate Impacts Aquatic Impacts Fish / Habitat: Potential for bridge pier on Surrey shoreline affects intertidal zone. Potential for bridge pier on New Westminster shoreline affects limited intertidal zone. River piers and associated armouring will displace subtidal substrates. Connection to King George Highway will displace Pattullo Drainage Channel with Class A fish habitat. Moderate Impacts Aquatic Impacts Wildlife / Habitat: Limited wildlife habitat capability / suitability associated with riparian vegetation if bridge pier located on New Westminster shoreline. Potential for bridge pier on Surrey shoreline affects riparian vegetation. Connection to King George Highway will displace Pattullo Channel & riparian vegetation. Moderate Impacts Archaeological Impacts: In New Westminster, there is no preferred option. In Surrey, the alignment is in close proximity to archaeological site DhRr-002; the highest archaeological potential is beneath and adjacent to the CN Rail ROW between sites DhRr- 002 and DhRr-074. The alignment is also located within site DhRr-064, formerly the BCER Interurban Line ROW. Lower Anticipated Impacts 14 Pattullo Bridge Alignment Assessment

18 Upstream Alignment: Terrestrial Impacts Vegetation: New Westminster connections will affect bluff and park vegetation; impacts to heritage chestnut tree between Wellington Street and Columbia Street can likely be minimized due to simplified connection configuration. Low Impacts Terrestrial Impacts Wildlife / Habitat: Limited wildlife habitat capability / suitability associated with park & bluff vegetation. Low Impacts Aquatic Impacts Vegetation: Potential for bridge pier on Surrey shoreline affects limited riparian vegetation. Connection to King George Highway to cross over railway and Musqueam Drainage Channel. Moderate Impacts Aquatic Impacts Fish / Habitat: Potential for bridge pier on Surrey shoreline affects limited intertidal zone. Potential for bridge pier on New Westminster shoreline affects limited intertidal zone. River piers and associated armouring will displace subtidal substrates. Moderate Impacts Aquatic Impacts Wildlife / Habitat: Limited wildlife habitat capability / suitability associated with riparian vegetation if bridge pier located on New Westminster or Surrey shoreline. Low Impacts Archaeological Impacts: In New Westminster, there is no preferred option, however the upstream alignment is in closer proximity to designated historic building Dh-Rr-048 (the Woodland s Nurses Lodge). In Surrey, the upstream alignment is located within the boundaries of Dh-Rr-074, an area of significant archaeological potential, and crosses the CN Rail ROW, an area of heightened archaeological potential. The alignment also crosses the boundary of Dh-Rr-064, the former BCER Interurban Line ROW. Higher Anticipated Impacts 4.4 SUMMARY From the information presented in Table 1, it can be seen that the upstream alignment possesses higher benefits with lesser impacts. Based on these findings, it is recommended that the further transportation planning work continue with the upstream alignment with further refinement of this alignment dependent on the assessment of the bridge connection options (north and south) as well as any further effects to river navigation, environmental, geotechnical, and river hydraulic characteristics. 15 Pattullo Bridge Alignment Assessment

19 CRITERIA UNIT DOWNSTREAM UPSTREAM Alignment 1 Alignment 3 FINANCIAL Capital Cost - Facility $M Salvage Value $M Property $M Maintenance and Operations $M Total Cost (PV) $M CUSTOMER SERVICE Travel Time Savings $M Vehicle Operating Savings $M Traffic Safety (Δ) $M 0 7 Benefit / Cost (B/C) OTHER Pedestrian & Cyclist Accommodation Vehice Connections to MRN Property Impacts (displacement) Significant Improvement over existing conditions More complex connecton to MRN on the north side of the river 7 in New Westminster 9 in Surrey Park land impacts Significant Improvement over existing conditions Less compex connection to MRN at the north approach to the bridge 7 in New Westminster 9 in Surrey River Navigation Moderate Improvement Moderate Improvement Environmental Impact Low to potentially moderate impact on terrestrial (vegetation, wildlife) Moderate impact on aquatic (vegetation, fish, wildlife) Lower anticipated archaeological impacts Low impact on terrestrial (vegetation, wildlife) Low to moderate impact on aquatic (vegetation, fish, wildlife) Higher anticipated archaeological 16 Pattullo Bridge Alignment Assessment