UBC Undergraduate Research

Life cycle assessment of Georgia and Dunsmuir viaduct Dennert, Katherine; Plant, Sherwood Apr 3, 2012

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
18861-Dennert_K_et_al_SEEDS_2012.pdf [ 1.07MB ]
Metadata
JSON: 18861-1.0108567.json
JSON-LD: 18861-1.0108567-ld.json
RDF/XML (Pretty): 18861-1.0108567-rdf.xml
RDF/JSON: 18861-1.0108567-rdf.json
Turtle: 18861-1.0108567-turtle.txt
N-Triples: 18861-1.0108567-rdf-ntriples.txt
Original Record: 18861-1.0108567-source.json
Full Text
18861-1.0108567-fulltext.txt
Citation
18861-1.0108567.ris

Full Text

UBC Social Ecological Economic Development Studies (SEEDS) Student Report        Life Cycle Assessment of Georgia and Dunsmuir Viaduct Katherine Dennert Sherwood Plant University of British Columbia CIVL 498E April 3, 2012            Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report”.      PROVISIO This study has been completed by undergraduate students as part of their  coursework at the University of British Columbia (UBC) and is also a  contribution to a larger effort – the UBC LCA Project – which aims to  support the development of the field of life cycle assessment (LCA).    The information and findings contained in this report have not been through a  full critical review and should be considered preliminary.  If further information is required please contact the course instructor Rob Sianchuk                Life Cycle Assessment of Georgia and Dunsmuir Viaduct CIVL 498E Report  Submitted: April 3, 2012   Katherine DennertSherwood Plant  CIVL 498E – Georgia and Dunsmuir Viaduct LCA iii   Abstract This study sought to provide a baseline comparison point to the City of Vancouver for the construction of the Georgia and Dunsmuir viaducts, as well as an approximation of several of the end of life options that are possible.  This is accomplished by doing a quantity takeoff of the viaducts using a combination of OnScreen Takeoff and Excel.  The volumes developed from this were then modelled in Athena Impact Estimator in order to determine the net impact of the construction of the viaducts.  In order to model the end of life options of the viaducts were considered; Greenway or Cut and Haul removal.  Based on approximated models, Cut and Haul removal was found to have the lower environmental impact.  The results should be considered preliminary due to the lack of information, LCA tools available and time constraints to complete a more detailed analysis.  Further analysis is recommended to validate the material quantities and develop models of more detailed end of life scenarios.       CIVL 498E – Georgia and Dunsmuir Viaduct LCA iv   Table of Contents Abstract ......................................................................................................................................................... 3 1.0 Introduction ...................................................................................................................................... 6 2.0 Goal and Scope ................................................................................................................................. 7 3.0 Model Development ....................................................................................................................... 11 3.1. Structure ..................................................................................................................................... 11 3.1.1. Material Takeoff Development ........................................................................................... 11 3.1.2. Material Takeoff Assumptions ............................................................................................ 11 3.1.3. IE Inputs and IE Input Assumptions .................................................................................... 12 4.0 Results and Interpretation .............................................................................................................. 13 4.1. Inventory Analysis ....................................................................................................................... 13 4.1.1. Bill of Materials ................................................................................................................... 13 4.2. Impact Assessment ..................................................................................................................... 14 4.2.1. Impact Categories ............................................................................................................... 14 4.2.2. Uncertainty ......................................................................................................................... 18 4.2.3. End of Life Assessment ....................................................................................................... 18 4.2.4. Chain of Custody Inquiry ..................................................................................................... 20 4.2.5. Functions and Impacts ........................................................................................................ 20 4.2.5.1. Structure Functions ......................................................................................................... 20 4.2.5.2. Functional Units .............................................................................................................. 20 5.0 Conclusions ..................................................................................................................................... 21 Appendix A:  IE Input Document ................................................................................................................. 22 Appendix B:  IE Input Assumptions Document ........................................................................................... 26     CIVL 498E – Georgia and Dunsmuir Viaduct LCA v   List of Tables Table 1.1: Structure Characteristics .............................................................................................................. 6 Table 4.1: Dunsmuir Viaduct Bill of Materials ............................................................................................ 13 Table 4.2: Georgia Viaduct Bill of Materials................................................................................................ 13 Table 4.3: Global Warming Potential, kg CO2 eq ........................................................................................ 14 Table 4.4: Ozone Depletion Potential kg CFC-11 eq ................................................................................... 15 Table 4.5: Acidification Potential, Moles H+ eq .......................................................................................... 15 Table 4.6: Eutrophication Potential, kg N eq .............................................................................................. 15 Table 4.7: Smog Potential, kg NOx eq ......................................................................................................... 16 Table 4.8: Human Health Respiratory Potential, kg PM2.5 eq ................................................................... 16 Table 4.9: Weighted Resource Use, kg ....................................................................................................... 17 Table 4.10: Fossil Fuel Use, MJ ................................................................................................................... 17 Table 4.11 Greenway Impact ...................................................................................................................... 19 Table 4.12  Cut and Haul Impacts ............................................................................................................... 19  CIVL 498E – Georgia and Dunsmuir Viaduct LCA 6   1.0 Introduction The Georgia and Dunsmuir Viaducts originated as a single viaduct structure in 1915 to connect the eastern side of Vancouver to the downtown area. It crossed an industrialized area of False Creek. In the early 1960s Vancouver decided to replace this structure with two viaducts that would hopefully become a part of a larger inter-city freeway system. The proposed freeway system was cancelled in the late 1960s, but by this time construction on the current Georgia and Dunsmuir Viaducts was already approved and moving forward. The Georgia and Dunsmuir Viaducts were then finished construction in 1972. Georgia and Dunsmuir Viaducts are now reaching a period in their life spans where the surrounding area is being considered for redevelopment by the City of Vancouver and developers. This has led the City of Vancouver to investigate and consider what should be done with the Viaducts. They are interested in evaluating the environmental impacts that the viaducts have had and the impacts of potential end-of-life options. The generic options that are being investigated are completed demolition, partial demolition, and greening of a viaduct. The consulting engineers on the viaduct project in 1972 were Phillips, Barratt, Hillier, Jones and Partners, and the as-built drawings were completed on February 22, 1973. The viaducts are in place to allow for vehicles, cyclists, and pedestrians to travel between Vancouver’s downtown core, and the Eastside of Vancouver.  Overall, the viaduct structures include the structural components and accessories that are listed in Table 1.1. Table 1.1: Structure Characteristics Footings Reinforced concrete boxes supporting reinforced concrete piers Piers Reinforced concrete columns supporting reinforced concrete cross-girders and stringers Cross girder arms Reinforced concrete support arms suspending the reinforced concrete stringers Stingers Reinforced concrete I-beams  with post-tensioning steel suspended from the cross-girders and supporting concrete decking Concrete deck 9 inch thick concrete slab suspended by the stringers Asphalt topping Road surface placed on top of concrete decking Side rails Reinforced concrete barriers with aluminum railings   CIVL 498E – Georgia and Dunsmuir Viaduct LCA 7   2.0 Goal and Scope The goal and scope of the study for the Georgia and Dunsmuir Viaducts allows for the definition of the analysis and interpretation that will be utilized throughout the study. The defined terms and clauses will also lead to appropriate recommendations. This section defines the goal and scope of this study in accordance with ISO 14044 Clause 4.2.2 and 4.2.3 (Canadian Standards Association, 2006).  Intended application  Describes the purpose of the study. Examine life cycle impacts of creating the viaduct structures, and end of life scenarios in order to inform decision making around reducing the impacts of their end-of-life/next phase.  Reason for carrying out the study Describes the motivation for carrying out the LCA study. City of Vancouver wants a base line to examine future transportation infrastructure projects’ environmental impacts.  Intended audience , ie to whom the results of the study are intended to be communicated Describes those who the LCA study is intended to be interpreted by. City of Vancouver officials and employees, as well as those keen to learn about life cycle assessment (LCA).  Whether the results are intended to be used in comparative assertions intended to be disclosed to the public State whether the results of this LCA are to be compared with the results of other LCA studies. Yes, the results of this LCA study will be available to the public and can be compared with the results of other LCA studies or similar infrastructure of functional equivalence.  It is strongly recommended that the Goal & Scope be consulted to ensure a fair comparison.  Product system to be studied Describes the collection of unit processes that will be included in the study The product system includes those unit processes involved in the resource extraction and manufacturing of the construction and energy products used to create the viaduct, as well as those required in the two end of life scenarios.  Functions of the product system or, in the case of comparative studies, the system Describes the functions served by the product focused on in the LCA study The function of the viaducts is to provide a safe transportation surface between East Vancouver and the Downtown core.   CIVL 498E – Georgia and Dunsmuir Viaduct LCA 8    Functional unit A performance characteristic of the product system being studied that will be used as a reference unit to normalize the results of the study The functional unit is per m2 area of elevated transportation surface (includes road and sidewalk).  System boundary Details the extent of the product system to be studied in terms of product components, life cycle stages, and unit processes. The system boundary of this project includes the construction and deconstruction of the footings, piers, cross girders, stringers, concrete deck, asphalt topping, and side-rails for the Georgia and Dunsmuir Viaducts. It does include investigating the potential end-of-life options of deconstruction (Cut and Haul) and greening (Greenway) scenarios. The maintenance and use of the viaducts is not included in the system boundary.  Allocation procedures Describes how the input and output flows of the studied product system (and unit processes within it) are distributed between it and other related product systems. No allocation was required in this study.  LCIA methodology and types of impacts State the methodology used to characterize the LCI results and the impact categories that will address the environmental and other issues of concern. The primary impact assessment method used in the BE Building LCA study was the Tool for the Reduction and Assessment of Chemical and other environmental Impacts (TRACI), developed by the US Environmental Protection Agency (US EPA).  An impact characterization method developed by the Athena Institute was also used to characterize weighted raw resource use and fossil fuel consumption. The impact categories selected and the units used to express them (i.e. category indicators) are listed below:  Global warming potential – kg CO2 equivalents  Ozone depletion potential – kg CFC-11 equivalents  Acidification potential – H+ mol equivalents  Eutrophication potential – kg N equivalents  Photochemical smog potential – kg NOx equivalents  Human health respiratory effects potential – kg PM2.5 equivalents  Weighted raw resource use – kg  Fossil fuel consumption – MJ   CIVL 498E – Georgia and Dunsmuir Viaduct LCA 9    Interpretation to be used Statement of significant issues, model evaluation results, and concluding remarks. Assumptions and interpretations are discussed in the Results and Interpratation section of this report. Any concluding remarks are contained in the Conclusion section.  Data requirements Explicit statement of all the data sources used to measure, calculate or estimate information from in order to complete the study of the product system. The data that was used in this study was collected from the as-built drawings that the City of Vancouver had on record and provided. Some questions were also asked of experts in the field of viaduct and bridge construction to gather what are typical types of materials and maintenance that can be expected on such structures.  Assumptions Explicit statement of all assumptions used by the modeller to measure, calculate or estimate information in order to complete the study of the product system. As a part of this report an IE Assumptions document is enclosed as an appendix. This document lists all the assumptions that were made during this study.  Value choices and optional elements Details of the application and use of normalization, grouping, weighting and further data quality analysis used to better understand the LCA study results. Due to the limitations of this study, and the time necessary, value choices and optional elements are not included. However, sufficient documentation is provided within this document to carry forth with further analysis.  Limitations Describe the extents to which the results of the modelling carried out on the product system accurately estimate the impacts created by the product system defined by the system boundary of the study. It is important to consider the system boundaries, assumptions and data quality.  Data quality requirements Qualitative and quantitative description of sourced data used in the LCA study, as well as the methods used to collect and integrate missing data. The data used in this study was collected from drawings provided by the City of Vancouver. These drawings were not a complete set, and the General Notes page was one of the missing sheets. Also one of the sheets with the Georgia Dunsmuir approaches meeting, G5 to G7 and GMS5 to G7, was also missing. This impacted the quality of data and required for many assumptions and estimation to be made.  Type of critical review, if any A review of the methods, data, interpretations, transparency and consistency of the LCA study – to be included in the LCA report. Although this study is prebared to be compared with other end-of-life phases for the viaducts a critical review of the study is not included in this report. If one wishes to  CIVL 498E – Georgia and Dunsmuir Viaduct LCA 10   utilize or include these results in future studies or reports it is advised they contact the authors of this report.  Type and format of the report required for the study Statement of the type and format followed by the report. This report was drafted in accordance to the provided outline for CIVL  498E – Winter Session 2012. It also takes into consideration ISO 14040 and ISO 14044.  CIVL 498E – Georgia and Dunsmuir Viaduct LCA 11   3.0 Model Development This section outlines the methodology that was used to develop the material takeoff, associated assumptions, and the inputs for the impact estimator model. 3.1.  Structure 3.1.1. Material Takeoff Development The quantity takeoffs were done using a combination of methods.  Because of the large repetition of shapes that had varied heights, strictly using OnScreen takeoff was not an option.  Instead OnScreen takeoff was used to develop the cross sectional areas and linearly dependant volumes of basic structures that were measured.  This data was then imported into Excel, and a range of formulae and spreadsheets were used to develop the volumes of material used. Due to the age and scanning of the drawings there was a significant amount of optical distortion.  This made accurate takeoffs difficult as some quantities, labels, and figures were difficult to interpret.  There was also a number of missing pages from the drawings, which lead to an added difficulty when it came to certain volumes and assumptions. 3.1.2. Material Takeoff Assumptions The pier foundations were done strictly in excel, using the conditions defined by the drawings.  For instance, foundation type F-I was a rectangular type foundation with a depth of 6’ 0”, a width of B, and a height of A.  By entering this formula into excel, in combination with the table of values presented by the drawings, a concrete volume estimation was established for foundations. The pier pedestal volumes were calculated using the same technique used for foundations. The piers themselves involved several steps.  First of all, as there are 12 possible cross sections for piers, with 5 different elevations based rebar schedules.  An area takeoff was done using OnScreen Takeoff of the 12 different possible concrete cross sections for the piers.  Linear takeoffs were done at each of the 60 different cross sections to determine horizontal rebar volumes per unit height of a pier.  Count takeoffs were used to calculate cross sectional area of rebar per unit height of a pier.  This information was transferred into Excel, where a set of calculations were performed based on the information available from the drawings. The Pier Cross girder’s used a similar method to the piers themselves, though more assumptions were made.  Due to the complexity of the cross girder’s shape, and the difficulty in calculating their individual shapes because of variation it was necessary to idealize the shape as a simple chevron, and the volume was calculated for each chevron using excel.  The exception to this were the cross girders for G6 North and South, and D6 North and South, for which the takeoffs were completed in OnScreen Takeoff.  CIVL 498E – Georgia and Dunsmuir Viaduct LCA 12   The concrete surface spans were calculated entirely in OnScreen Takeoff using area measurements.  Assumptions had to be made in the consistency of the concrete thickness across both viaducts. The I-Bean spans were first measured in cross-sectional area from OnScreen Takeoff, as well as rebar areas per unit length.  The length and number of spans were tabulated again using OnScreen Takeoff and the total volume of concrete and rebar was calculated inside Excel. The guard railings were done using two area measurements and one linear measurement in OnScreen Takeoff.  The area measurements were the cross section of the concrete curb, and the cross section of the metal rail.  The linear measurement was the length of rail on each side of each viaduct.  The total volume of the rail was calculated in excel by combining these values. 3.1.3. IE Inputs and IE Input Assumptions This study utilized many sources of data and inputs. These inputs are outlined in the IE Input Document which is attached to this report as Appendix A. Appendix B outlines the assumptions that were made in relation to the inputs into our Impact Estimator. CIVL 498E – Georgia and Dunsmuir Viaduct LCA 13   4.0 Results and Interpretation 4.1.  Inventory Analysis 4.1.1. Bill of Materials By completing takeoffs for the viaduct structures a bill of materials was developed outlining all of the materials that were used in their construction. Table 4.1 outlines the metric quantities that make up the Dunsmuir Viaduct, while Table 4.2 outlines the bill of materials used in the Georgia Viaduct. Table 4.1: Dunsmuir Viaduct Bill of Materials Material Quantity Unit Aluminum 9 Tonnes Concrete 20 MPa (flyash av) 6458 m3 Concrete 30 MPa (flyash 25%) 1653 m3 Rebar, Rod, Light Sections 265 Tonnes Welded Wire Mesh / Ladder Wire 16 Tonnes Emulsified Asphalt Primer Coat 10 Tonnes Superpave 9.5 1902 Tonnes   Table 4.2: Georgia Viaduct Bill of Materials Material Quantity Unit Aluminum 9 Tonnes Concrete 20 MPa (flyash av) 7084 m3 Concrete 30 MPa (flyash 25%) 1408 m3 Rebar, Rod, Light Sections 240 Tonnes Welded Wire Mesh / Ladder Wire 18 Tonnes Emulsified Asphalt Primer Coat 10 Tonnes Superpave 9.5 2088 Tonnes  The largest quantity, by far, was concrete, in total it accounted for 16,602 cubic meters, or approximately 40,000 tonnes.  Compare this to the second most abundant material, Asphalt, which accounted for just under 4,000 tonnes.  The third most present material is steel reinforcing rebar, which accounts for just over 500 tonnes. It is important to reference the Assumptions Document in Appendix B to understand the assumptions that were required in calculating the volumes associated with concrete.  In some cases, particularly for the cross girders where more assumptions were made regarding the shape and intersection space of the piers, a number of smaller models were summed together to form the total.  In this case, any small mistakes may propagate throughout the whole system.  CIVL 498E – Georgia and Dunsmuir Viaduct LCA 14   Because the exact specifications of the asphalt lift on the viaducts are unknown, an assumption had to be made there regarding both the material used as well as the lift thickness.  Variations in both of these values could affect the entire mass by a significant amount over the total surface of the viaducts. Rebar will not vary as much, as the takeoff was done on more linear measurements within OnScreen Takeoff.  That said, there is room for some errors to propagate and create a slight variation off of the real values. 4.2. Impact Assessment 4.2.1. Impact Categories In this section, the characterization of the LCA models are presented to provide some context to the estimated resources and energy consumed and air, water and land emissions resulting from the product system process activity. As mentioned in the Goal & Scope, the impact assessment method used is the US EPA’s Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI), which includes impact categories of primary energy consumption, weighted resource use, global warming potential, acidification potential, human health (HH) respiratory effects potential, eutrophication potential, ozone depletion potential, and smog potential. The following tables are adapted from ISO 21931-1, and summarize the impacts with respect to each impact category for the manufacturing and construction of each of the viaduct components. The tables only include the manufacturing and construction phase of the viaduct life cycle as the use phase was not within the scope of this study. In addition, the end-of-life options will be examined within Section 4.2.3. Table 4.3: Global Warming Potential, kg CO2 eq Life Cycle Stage Process Global Warming Assembly Group Piers Footings Girders Stringers Decking Side Rails Paving Total Manufacturing Material kg CO2 eq 1095063.67 1554077.03 209826.81 972151.84 3336597.54 133419.33 406988.67 7708124.89   Transportation kg CO2 eq 36858.85 52308.82 7062.58 32721.75 112306.83 4490.77 13698.87 259448.46   Total kg CO2 eq 1131922.52 1606385.85 216889.38 1004873.58 3448904.38 137910.11 420687.54 7967573.36 Construction Material kg CO2 eq 239288.15 339589.58 45850.36 212430.03 729097.56 29154.16 88933.24 1684343.10   Transportation kg CO2 eq 63475.14 90081.75 12162.57 56350.58 193405.18 7733.62 23591.01 446799.86   Total kg CO2 eq 302763.29 429671.34 58012.93 268780.61 922502.74 36887.79 112524.26 2131142.95        CIVL 498E – Georgia and Dunsmuir Viaduct LCA 15    Table 4.4: Ozone Depletion Potential kg CFC-11 eq Life Cycle Stage Process Ozone Depletion Potential Assembly Group Piers Footings Girders Stringers Decking Side Rails Paving Total Manufacturing Material kg CFC-11 eq 2.549E-03 3.617E-03 4.884E-04 2.263E-03 7.767E-03 3.106E-04 9.474E-04 1.794E-02   Transportation kg CFC-11 eq 1.526E-06 2.166E-06 2.925E-07 1.355E-06 4.651E-06 1.860E-07 5.673E-07 1.074E-05   Total kg CFC-11 eq 2.551E-03 3.620E-03 4.887E-04 2.264E-03 7.771E-03 3.108E-04 9.479E-04 1.795E-02 Construction Material kg CFC-11 eq 8.370E-06 1.188E-05 1.604E-06 7.430E-06 2.550E-05 1.020E-06 3.111E-06 5.892E-05   Transportation kg CFC-11 eq 2.592E-06 3.679E-06 4.967E-07 2.301E-06 7.899E-06 3.159E-07 9.635E-07 1.825E-05   Total kg CFC-11 eq 1.096E-05 1.556E-05 2.101E-06 9.732E-06 3.340E-05 1.336E-06 4.074E-06 7.716E-05  Table 4.5: Acidification Potential, Moles H+ eq Life Cycle Stage Process Acidification Assembly Group Piers Footings Girders Stringers Decking Side Rails Paving Total Manufacturing Material Moles H+ eq 353843.21 502162.22 67800.43 314127.24 1078140.40 43111.22 131508.50 2490693.21  Transportation Moles H+ eq 13510.60 19173.78 2588.79 11994.15 41166.04 1646.09 5021.32 95100.76  Total Moles H+ eq 367353.81 521336.00 70389.22 326121.38 1119306.44 44757.31 136529.81 2585793.98 Construction Material Moles H+ eq 78690.51 111674.89 15078.01 69858.15 239765.57 9587.42 29245.92 553900.47  Transportation Moles H+ eq 20002.16 28386.38 3832.64 17757.08 60945.46 2437.00 7433.95 140794.68  Total Moles H+ eq 98692.67 140061.27 18910.65 87615.23 300711.03 12024.42 36679.87 694695.15  Table 4.6: Eutrophication Potential, kg N eq Life Cycle Stage Process Eutrophocation Assembly Group Piers Footings Girders Stringers Decking Side Rails Paving Total Manufacturing Material Kg N eq 377.61 535.90 72.36 335.23 1150.57 46.01 140.34 2658.01   Transportation Kg N eq 14.13 20.05 2.71 12.54 43.04 1.72 5.25 99.44   Total Kg N eq 391.74 555.94 75.06 347.77 1193.61 47.73 145.59 2757.45 Construction Material Kg N eq 77.41 109.86 14.83 68.72 235.88 9.43 28.77 544.91   Transportation Kg N eq 20.72 29.41 3.97 18.40 63.14 2.52 7.70 145.87   Total Kg N eq 98.14 139.27 18.80 87.12 299.02 11.96 36.47 690.78          CIVL 498E – Georgia and Dunsmuir Viaduct LCA 16   Table 4.7: Smog Potential, kg NOx eq Life Cycle Stage Process Smog Potential Assembly Group Piers Footings Girders Stringers Decking Side Rails Paving Total Manufacturing Material kg Nox eq 3698.27 5248.47 708.63 3283.17 11268.44 450.59 1374.49 26032.06   Transportation kg Nox eq 307.25 436.04 58.87 272.77 936.18 37.43 114.19 2162.74   Total kg Nox eq 4005.53 5684.51 767.50 3555.94 12204.61 488.02 1488.68 28194.80 Construction Material kg Nox eq 1700.43 2413.19 325.82 1509.57 5181.10 207.17 631.98 11969.26   Transportation kg Nox eq 446.55 633.73 85.56 396.43 1360.63 54.41 165.97 3143.29   Total kg Nox eq 2146.98 3046.92 411.39 1906.00 6541.73 261.58 797.94 15112.54  Table 4.8: Human Health Respiratory Potential, kg PM2.5 eq Life Cycle Stage Process Respiratory Impacts Assembly Group Piers Footings Girders Stringers Decking Side Rails Paving Total Manufacturing Material kg PM2.5 eq 2524.68 3582.93 483.76 2241.30 7692.55 307.60 938.31 17771.13   Transportation kg PM2.5 eq 16.33 23.18 3.13 14.50 49.77 1.99 6.07 114.97   Total kg PM2.5 eq 2541.01 3606.12 486.89 2255.80 7742.32 309.59 944.39 17886.11 Construction Material kg PM2.5 eq 104.30 148.01 19.98 92.59 317.79 12.71 38.76 734.14   Transportation kg PM2.5 eq 24.04 34.12 4.61 21.34 73.25 2.93 8.93 169.22   Total kg PM2.5 eq 128.34 182.13 24.59 113.93 391.03 15.64 47.70 903.36  CIVL 498E – Georgia and Dunsmuir Viaduct LCA 17   Table 4.9: Weighted Resource Use, kg Life Cycle Stage Process Weighted Resource Assembly Group Piers Footings Girders Stringers Decking Side Rails Paving Total Manufacturing Material kg 13300409.75 18875488.13 2548511.62 11807548.81 40525601.96 1620482.77 4943197.57 93621240.61   Transportation kg 13500.53 19159.49 2586.86 11985.21 41135.36 1644.86 5017.57 95029.88   Total kg 13313910.28 18894647.62 2551098.47 11819534.02 40566737.31 1622127.64 4948215.14 93716270.48 Construction Material kg 73372.23 104127.37 14058.96 65136.81 223561.07 8939.46 27269.34 516465.24   Transportation kg 19969.50 28340.04 3826.39 17728.09 60845.95 2433.03 7421.82 140564.81   Total kg 93341.73 132467.41 17885.35 82864.90 284407.02 11372.48 34691.16 657030.05  Table 4.10: Fossil Fuel Use, MJ Life Cycle Stage Process Fossil Fuel Assembly Group Piers Footings Girders Stringers Decking Side Rails Paving Total Manufacturing Material MJ 16374906.27 23238708.80 3137620.54 14536958.55 49893420.31 1995070.38 6085857.39 115262542.24   Transportation MJ 574790.16 815722.60 110136.41 510274.72 1751353.35 70030.74 213625.10 4045933.09   Total MJ 16949696.43 24054431.40 3247756.96 15047233.27 51644773.66 2065101.12 6299482.48 119308475.32 Construction Material MJ 3121407.78 4429795.53 598097.66 2771055.59 9510754.32 380303.14 1160094.74 21971508.76   Transportation MJ 847551.27 1202815.87 162400.58 752420.66 2582441.15 103263.15 314998.82 5965891.51   Total MJ 3968959.06 5632611.40 760498.24 3523476.25 12093195.47 483566.29 1475093.56 27937400.27  CIVL 498E – Georgia and Dunsmuir Viaduct LCA 18   4.2.2. Uncertainty The project presents a rather large amount of uncertainty stemming primarily from a deficit of information and the lack of an LCA tool to handle viaduct analysis. The takeoff method used required a large number of calculations outside of OnScreen Takeoff.  The Takeoff method could only be relied on for area measurements, when the various heights and different cross sections were taken into account, an external compiling software was required.  A large number of Excel formulas worked to achieve this.  Unfortunately, due to a combination of rounding changes, and potential errors in the formulas, a source of error is introduced with this intermediate step. As mentioned earlier, the age of the drawings also contributes to the uncertainty.  Many drawings were signed off in 1969, and the scanned versions of these are missing sections of text, blurred out text due to low resolution, mis-scanned text, or blacked out text.  This makes it difficult to perform the proper takeoff in OnScreen Takeoff and errors can be introduced.  This was particularly problematic in the transferring of large volumes of values from tables in the drawings into Excel, when some numbers could be misinterpreted.  In some cases a 6 or an 8 could be confused, leading to 2 foot differences in measurements. Another significant area of uncertainty was the information deficit.  Due to the age of the project, as well as the change in construction technology, many of the production methods are unknown.  For instance, the specific composition of concrete used in the viaducts is unknown, due to a missing general notes page.  As a result the impact associated with concrete may vary as the specific mixture varies.  The same is true for asphalt, as well as the specific construction methods used in assembling the viaducts.  Machinery impacts are difficult to account for because, while it is possible to predict what equipment was used in the assembly, it is hard to know what their working hours were and how that will affect the impact. The final source of uncertainty was the lack of specialized life cycle assessment software.  Athena Impact Estimator for Buildings and Athena Impact Estimator for Highways, while strong software for building estimation and highway estimate respectively, are not designed for conducting LCAs on bridges and viaducts.  Unfortunately, there are no other available LCA tools for use in this study, so these tools were used to develop results in using the material takeoffs.  The anticipated results are some material additions, changes in rebar ratio, or smaller values. 4.2.3. End of Life Assessment Two end-of-life options for the viaducts were analysed; converting them into a greenway, like High Line Park in New York, or using a Cut and Haul method of removal.  By comparing their potential impacts, it should be possible to draw some conclusions regarding which option is better, or if there is an optimal combination of the two. The first method, greenway construction, would add a lift of rubberized asphalt in order to seal the viaduct surface.  A layer of drainage rock would be added above that in order to drain away excess water during rain or water and prevent standing puddles.  On top would be a lift of loam  CIVL 498E – Georgia and Dunsmuir Viaduct LCA 19   that would be populated with grass and plant life.  This method is viewed as low impact, while improving green space in the region. The second option is Cut and Haul.  This requires large section of the viaduct to be saw cut and then, using a crane or excavator, placed in haul vessels.  The option for haul that was analysed was barging from the viaducts to the North Vancouver concrete recycling facility.  A trip of approximately 18km.  This was determined to be one of the most effective methods of removal. Table 4.11 Greenway Impact Impact category Manufacturing Construction Overall Material Transport Total Material Transport Total Total Fossil Fuel Consumption MJ eq. 31830795.70 208683.59 32039479.30 11661285.41 1202067.37 12863352.78 89805664.14 Weighted Resource Use kg 25580220.94 4917.07 25585138.01 274558.47 28323.50 302881.98 51776039.98 Global Warming Potential CO2 eq. 237765.78 16019.21 253784.99 906173.41 92274.46 998447.88 2504465.74 Acidification Potential H+ moles eq. 146078.50 4926.95 151005.45 279212.16 28380.41 307592.57 917196.04 HH respirator effects PM2.5 eq. 1013.38 5.92 1019.30 381.20 34.11 415.31 2869.22 Eutrophocation Potential N eq. 107.03 5.10 112.14 275.37 29.40 304.77 833.82 Ozone Depletion Potential CFC-11 eq. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Smog Potential Nox eq. 991.63 110.02 1101.65 5914.69 633.73 6548.42 15300.14  Table 4.12  Cut and Haul Impacts Impact category Deconstruction Recycling Transport Total Global warming CO2 eq. 18784.63 41983.92 60768.55 Acidification H+ moles eq. 6271.73 49265.89 55537.63 Respiratory effects PM2.5 eq. 8.29 55.88 64.17 Eutrophication N eq. 5.99 46.39 52.38 Smog NOx eq. 127.94 1050.77 1178.71 Total energy MJ eq 259886.20 573061.80 832948.00 Fossil energy MJ eq 257320.48 567404.25 824724.72 Non-renewable, nuclear MJ eq 2189.03 4826.93 7015.96 Renewable energy MJ eq 376.69 830.63 1207.32  All model uncertainties considered, it would appear that Cut and Haul has a drastically lower impact than a greenway.  It should be considered that the delivered services from these scenarios are not perfect functional equivalents, as the Cut and Haul does not include the development of the greenspace provided by the greenway, and the greenway does not provide the street level development space of the Cut and Haul.  Further analysis of these scenarios should address this in the LCA model development. Taking the above results at face value, however, would indicate that removing the viaducts completely is the correct course of action based solely on this impact estimation.   CIVL 498E – Georgia and Dunsmuir Viaduct LCA 20   4.2.4. Chain of Custody Inquiry This study included investigating the chain of custody for concrete. Lehigh Concrete Group is a group of local concrete manufacturers that manage all links in the supply chain, from resource extraction to ready-mix delivery. They were contacted as they were likely the concrete suppliers for the viaduct structures during their construction. Their chain of custody, with regards to their aggregate suppliers, cement suppliers, etc., is the shared amongst the Ocean Concrete Group and Allied Ready Mix. Lehigh Concrete Group gets its extracted aggregate from Sechelt Island and then the aggregate is barged to the mix facilities. The Cement is manufactured at their plant in Delta, BC and is then shipped via barge or truck to the mix facilities. The fly ash that is used in their mixes is sourced from Edmonton, AB and typically shipped to the mixing facilities in Vancouver via rail or truck. There are three Lehigh Concrete mixing facilities in the Lower Mainland. These mix facilities are located on Mitchell Island in Richmond, Granville Island in Vancouver, and in North Vancouver. The ready mix concrete is then loaded into a concrete truck and transported to site. Lafarge is the other current major supplier of concrete within the Lower Mainland. Their facilities are a further distance from the viaducts and not likely to be the supplier of the concrete to this structure. Their chain of custody information was not available upon request. 4.2.5. Functions and Impacts The following section outlines the function that the Georgia and Dunsmuir Viaducts provide, and the functional unit that is used to measure the impacts of the viaducts. 4.2.5.1. Structure Functions The Georgia and Dunsmuir Viaducts serve as a part of the transportation infrastructure within the Lower Mainland. Its one function is to provide a means for vehicles, cyclists and pedestrians to travel between Vancouver’s downtown core and East Vancouver. One hundred percent of the surface of the viaducts contributes to this function. 4.2.5.2. Functional Units In a LCA study, a functional unit is a performance characteristic of the product system that will be utilized to express LCA results relative to its delivered performance. In this study, the functional unit relatively measures the performance of the viaduct structures. As previously mentioned, the viaducts provide a transportation solution for vehicles, cyclists and pedestrians. This study is designed to determine the effect of the viaducts have, and the effects of alternative solutions for the end-of-life of the viaducts. Considering the function that the viaducts serve the functional unit is:  Per m2 area of elevated transportation surface (includes road and sidewalk) In order to equate results using functional units, the total impacts of the viaducts need to be divided by their total area of road and sidewalk. CIVL 498E – Georgia and Dunsmuir Viaduct LCA 21   5.0 Conclusions This LCA study applied LCA methods to create models of the Georgia and Dunsmuir viaducts from drawings.  These models made it possible to provide a preliminary estimate of the impact of construction and end of life for the two viaducts which can be used as a benchmark for further development in the area of urban highways, and even as a comparison point for all road construction projects in the City of Vancouver.  This information will allow urban planners to make more informed decisions when it comes to determining transportation infrastructure in the City. The study found that the optimal end of life option for the viaducts is the removal by a Cut and Haul scenario.  This should be taken with a grain of salt, however, since there was lack of information and LCA tools to complete a more detailed analysis to be done with confidence.  Time constraints also caused issues with researching end of life modelling.   It is recommended that future work on estimating the impacts of removing the viaducts begin by validating the material quantities estimated for the viaducts.  Then, research and develop end of life models using more sophisticated LCA modelling techniques and more complete datasets on machinery type and their useage. CIVL 498E – Georgia and Dunsmuir Viaduct LCA 22   Appendix A:  IE Input Document     CIVL 498E – Georgia and Dunsmuir Viaduct LCA 23    IE Inputs Document Assembly Group Assembly Name Input Fields Input Values Known/Measured IE Inputs 1  Piers 1.1 Georgia Viaduct Cast-in-place Piers Number of Piers 28 29   Elevations (ft) varied varied   Volume of concrete (tonnes) 9678.2415 9678.2415   Concrete (psi) unknown 4000   Concrete flyash % unknown 2500%   Volume of rebar (tonnes) 2.013801814 2.013801814  1.2 Dunsmuir Viaduct  Cast-in-place Piers Number of Piers 24 24   Elevations (ft) varied varied   Volume of concrete (tonnes) 8226.16441 8226.16441   Concrete (psi) unknown 4000   Concrete flyash % unknown 2500%   Volume of rebar (tonnes) 1.705662184 1.705662184 2 Footings 2.1 Georgia Viaduct Concrete pile cap/foundations Number of foundations 28 1   Volume of concrete (tonnes) 13780.73719 13780.73719   Concrete (psi) unknown 3000   Concrete flyash % unknown average   Volume of rebar (tonnes) 7.014395229 7.014395229  2.1 Dunmuir Viaduct Concrete pile cap/foundations Number of foundations 24 1   Volume of concrete (tonnes) 11620.93444 11620.93444   Concrete (psi) unknown 3000   Concrete flyash % unknown average   Volume of rebar (tonnes) 5.91505563 5.91505563 3 Cross Girders 3.1 Georgia Viaduct Cross girders Number of cross girders 28 28   Volume of concrete (tonnes) 1667.393756 1667.393756   Concrete (psi) unknown 4000  CIVL 498E – Georgia and Dunsmuir Viaduct LCA 24     Concrete flyash % unknown 2500%   Volume of rebar (tonnes) 176.192396 176.192396  3.2 Dunsmuir Viaduct Cross girders Number of cross girders 24 24   Volume of concrete (tonnes) 1437.740942 1437.740942   Concrete (psi) unknown 4000   Concrete flyash % unknown 2500%   Volume of rebar (tonnes) 150.07588 150.07588 4 Stringers 4.1 Georgia Viaduct Precast I-beam stringers Number of I-beams per span varies per span varies per span   Span length (ft) varies per span varies per span   Total number of i-beams 142 142   Total length of i-beams 2635.128 2635.128   Total volume of concrete (tonnes) 8115.986 8115.986   Concrete (psi) unknown 3000   Concrete flyash % unknown average   Total volume of rebar (tonnes) 348.2291895 348.2291895  4.2 Dunsmuir Viaduct Precast I-beam stringers Number of I-beams per span varies per span varies per span   Span length (ft) varies per span varies per span   Total number of i-beams 170 170   Total length of i-beams 2918.25 2918.25   Total volume of concrete (tonnes) 7124.00158 7124.00158   Concrete (psi) unknown 3000   Concrete flyash % unknown average   Total volume of rebar (tonnes) 309.869721 309.869721 5 Decking 5.1 Georgia Viaduct 9" concrete slab Total surface area (sq ft) 186554 186554   total volume (tonnes) 28559.1735 28559.1735   Concrete (psi) unknown 3000   Concrete flyash % unknown average  5.2 Dunsmuir Viaduct 9" concrete slab Total surface area (sq ft) 169876 169876   total volume (tonnes) 26005.8794 26005.8794   Concrete (psi) unknown 3000  CIVL 498E – Georgia and Dunsmuir Viaduct LCA 25     Concrete flyash % unknown average 6 Side rails 6.1 Georgia viaduct concrete (tonnes) 1059.98208 1059.98208   Concrete (psi) unknown 3000   Concrete flyash % unknown average   rebar (tonnes) 29.653 29.653   railing (tonnes) 8.553597252 8.553597252  6.2 Dunsmuir viaduct concrete (tonnes) 1050.71112 1050.71112   Concrete (psi) unknown 3000   Concrete flyash % unknown average   rebar (tonnes) 24.4947 24.4947   railing (tonnes) - aluminum 8.478784448 8.478784448 7 Paving 7.1 Georgia Viaduct topping primer 17.33587 17.33587   ashpalt 3620.487754 3620.487754   Asphalt Type unknown SuperPave 9.5  7.2 Dunsmuir Viaduct topping primer 15.78604 15.78604   ashpalt 3002.080164 3002.080164   Asphalt Type unknwon SuperPave 9.5  CIVL 498E – Georgia and Dunsmuir Viaduct LCA 26   Appendix B:  IE Input Assumptions Document    CIVL 498E – Georgia and Dunsmuir Viaduct LCA 27   IE Input Assumptions Document Assembly Group Assembly Name Specific Assumptions 1  Piers Because there is no assembly in the IE that would mimic the construction of the piers, given the higher rebar content and highly varied shapes, it was necessary to enter these into the IE as extra basic materials: both concrete are rebar quantities were determined externally and separately and the input into IE.  Concrete was entered as a raw volume (yards cubed), and rebar as a weight (tons).  1.1 Georgia Viaduct Cast-in-place Piers The concrete type was unknown, so it had to be entered based on assumed structural requirements.  In this case we consulted with two external sources who claimed that a 28 day strength of 4000psi at 25% flyash would be the likely concrete for construction.  The rebar was assumed to have a standard density of steel, and the volume was calculated used excel tables.  1.2 Dunsmuir Viaduct  Cast-in-place Piers The concrete type was unknown, so it had to be entered based on assumed structural requirements.  In this case we consulted with two external sources who claimed that a 28 day strength of 4000psi at 25% flyash would be the likely concrete for construction.  The rebar was assumed to have a standard density of steel, and the volume was calculated used excel tables. 2 Footings The footings were assumed to be constructed using a similar method as defined by Concrete Footing Foundations in the IE.  Unfortunately, because of the shear volume of footings involved, the volume of concrete used for all footings in one viaduct was used.  The thickness was assumed to be 1 foot, the width 25 feet, and the length determined from that.  The concrete was assumed to be 3000psi with #5 rebar.  The equation used to L = Volume/(width*height)  2.1 Georgia Viaduct Concrete pile cap/foundations The formula: Length = Volume/25 was used to calculate the length, which was input into the document as the length of the concrete slab assuming a depth of 1 foot and a width of 25 feet.  2.1 Dunsmuir Viaduct Concrete pile cap/foundations The formula: Length = Volume/25 was used to calculate the length, which was input into the document as the length of the concrete slab assuming a depth of 1 foot and a width of 25 feet. 3 Cross Girders The cross girders were also entered as extra basic materials.  Unfortunately, because of their complex geometry, it was difficult to get an exact volume of concrete and rebar used in their construction.  As a result the shape was idealized in excel as a chevron with a flat base, and the individual dimensions were pulled from the drawings.  This did represent a source of error as some of the numbers on the drawings were illegible.  CIVL 498E – Georgia and Dunsmuir Viaduct LCA 28    3.1 Georgia Viaduct Cross girders The width was assumed to be 5 feet based on the drawings for cross girders.  The width was assumed to be twice the value of g found in the design drawings.  The slope was assumed to be approximately 2% for the super elevation of the cross girder.  An exception to this was G6 North and South, which, due to unique and more complex geometry, was calculated in OnScreen Takeoff with an assumed thickness of 5 feet.  3.2 Dunsmuir Viaduct Cross girders The width was assumed to be 5 feet based on the drawings for cross girders.  The width was assumed to be twice the value of g found in the design drawings.  The slope was assumed to be approximately 2% for the super elevation of the cross girder.  An exception to this was D6 North and South, which, due to unique and more complex geometry, was calculated in OnScreen Takeoff with an assumed thickness of 5 feet. 4 Stringers The stringers were entered into the IE as extra basic material.  The volume calculation was done based on the cross sectional area of the stringer, the number of stringers per span, and the total length of each span.  The rebar weight was calculated in a similar way, based on the cross sectional area of rebar per linear meter.   4.1 Georgia Viaduct Precast I-beam stringers   4.2 Dunsmuir Viaduct Precast I-beam stringers  5 Decking The decking entered into the IE as concrete slab on grade.  Since the depth of concrete slab is limited to 4 or 8", the thickness was assumed to be 8" and the width assumed to be 25feet in order to ease calculations.  5.1 Georgia Viaduct 9" concrete slab The width of the span was assumed to be 25 feet, and the formula L = volume/(0.6667 feet*25 feet) in order to generate the appropriate values.  The volume was found by using the actual concrete thickness of 10" multiplied by the actual surface area of the road. Superelevation was ignored.  5.2 Dunsmuir Viaduct 9" concrete slab The width of the span was assumed to be 25 feet, and the formula L = volume/(0.6667 feet*25 feet) in order to generate the appropriate values.  The volume was found by using the actual concrete thickness of 10" multiplied by the actual surface area of the road. Superelevation was ignored. 6 Side rails The side rails were done as a linear measurement in TakeOff, as well as a cross section.  By multiplying the two, an approximation of concrete and rebar use was obtained.  Unfortunately, the guard rail has a more complicated shape, and  CIVL 498E – Georgia and Dunsmuir Viaduct LCA 29   so some of the variation in concrete shape was neglected.  The aluminium railing was calculated based on its cross sectional area multiplied by its length.  6.1 Georgia viaduct A single railing cross section was developed with concrete and rebar areas per unit length.  This was multiplied by the total length of railing in the structure.  6.2 Dunsmuir viaduct A single railing cross section was developed with concrete and rebar areas per unit length.  This was multiplied by the total length of railing in the structure. 7 Paving The paving was assumed to be a standard 50mm lift of SuperPave 9.5.  The IE for Highways was used with an assumed width of 10m, and a length calculated based on the surface area of the street divided by that width.  7.1 Georgia Viaduct topping      7.2 Dunsmuir Viaduct topping    

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.18861.1-0108567/manifest

Comment

Related Items