1. 1
Table of Contents
1.0 EXECUTIVE SUMMARY..................................................................................................................3
2.0 INTRODUCTION ............................................................................................................................4
2.1 Purpose...................................................................................................................................4
2.2 Description ..............................................................................................................................4
2.3 Design & Building Codes ...........................................................................................................4
3.0 SITE INFORMATION ......................................................................................................................4
3.1 Site & Bridge Location...............................................................................................................4
3.2 Existing Conditions...................................................................................................................5
4.0 PRELIMINARY BRIDGE DESIGNS ....................................................................................................5
4.1 Bridge Geometry Alternative #1................................................................................................5
4.2 Bridge GeometryAlternative #2................................................................................................6
4.3 Bridge Superstructure...............................................................................................................6
4.3.1 Bridge Loading Alt. #1.....................................................................................................8
4.4 Bridge Superstructure Alt. #2..................................................................................................10
4.4.1 Bridge Loading Alt. #1...................................................................................................10
4.5 Additional Considerations.......................................................................................................10
4.6 Bridge Substructure................................................................................................................ 11
4.7 Bridge Deck Drainage ............................................................................................................. 10
5.0 CONSTRUCTION PROCEDURES & AESTHETICS.............................................................................. 13
5.1 Preliminary Design #1............................................................................................................. 13
5.2 Preliminary Design #2............................................................................................................. 13
6.0 COST COMPARISON.................................................................................................................... 14
6.1 Preliminary Design #1............................................................................................................. 14
6.2 Preliminary Design #2............................................................................................................. 14
7.0 SUSTAINABILITY ......................................................................................................................... 15
8.0 CONCLUSIONS............................................................................................................................ 15
Preferred Alternative ................................................................................................................... 15
APPENDIX A.....................................................................................................................................16
A.1.1 Deck Load Calculations........................................................................................................16

2. 2
A.1.2 Superstructure Load Calculations......................................................................................... 18
A.1.3 Live Load Calculations.......................................................................................................... 19
A.2.1 Foundation Calculations ......................................................................................................20
APPENDIX B.....................................................................................................................................23
Project Validation Form................................................................................................................ 23
List of Tables
TABLE 1: Cost Comparison of Pre-StressedGirders..............................................................................7
TABLE 2: Alternative #1 Distributed Loads ..........................................................................................9
TABLE 3: Alternative #2 Distributed Loads ........................................................................................ 10
TABLE 4: Righting Moments for North Abutment.............................................................................. 11
TABLE 5: Cost Comparison of Alternatives......................................................................................... 14
List of Figures
FIGURE 1: Site and Bridge Location ....................................................................................................5
FIGURE 2: Typical Cross Section Alt. #1 ...............................................................................................6
FIGURE 3: Typical Cross Section Alt. #2 ...............................................................................................6
FIGURE 4: Steel (left) & Concrete (right) Beams ..................................................................................6
FIGURE 5: Beam Girder Selection Chart ..............................................................................................7
FIGURE 6: Loads Used to Calculate Design Truck Moment ...................................................................8
FIGURE 7: Design Truck Moment........................................................................................................9
FIGURE 8: Abutments on Spread Footings.........................................................................................12
FIGURE 9: Profile Views of Alternatives.............................................................................................12
FIGURE 10: Plan View of Alternatives................................................................................................13

3. 3
1.0 Executive Summary
TalkingStick Plazaisa proposedmixeduse development of approximately340 acres in the Salt
RiverPima-MaricopaIndianCommunity,locateddirectlyeastof the 101 Freeway &southof Talking
StickWay. Withthe southernexitof the 101 leadingtrafficeastdownMcDonaldDrive,DobsonRoad
neededabridge inorderto connectthe parts of the site dividedbythe ArizonaCanal asseeninfigure
one. A pre-stressedconcrete andasteel superstructure were comparedinordertodeterminea
preferredalternative. Aftercareful calculationof loadingandcostanalysisitwasdeterminedthatthe
precastpre-stressedconcrete bridge wasthe preferredalternativeasit not onlyoffers asavingsof
nearly$114,000, but is alsomore aesthetically pleasing, more sustainable,andhasa shorter
constructiontime.
DobsonRoad isproposedtobecome an arterial roadfor the site whichledthe bridge tohaving
twolanesineach directionaswell asa centerturninglane andpedestriansidewalks whichwill be
placedona nine-inchreinforcedconcrete deck.Pedestrianswillbe protectedbyArizonaDepartmentof
TransportationSD1.04 trafficbridge railing.The resultingbridgehas awidth76 feet, spanning115 feet,
and will be nine anda half feetabove the canal waterat mid-span.The bridge will be supportedoneach
endby abutmentsonspreadfootings,bothconstructedof reinforcedconcrete.

4. 4
2.0 Introduction
2.1 Purpose
TalkingStickPlazaisa proposeddevelopmentinthe SaltRiverPima-MaricopaIndian
Community,locateddirectlyeastof the 101 Freeway &southof TalkingStickWay. In orderto facilitate
trafficapproachingfromthe southof the site,DobsonRoadwill be extendedalongthe easternborder
of the site connecting TalkingStickWay tothe north and McDonaldDrive to the south.A bridge will
needtobe constructed overthe ArizonaCanal whichcutsthroughthe southern portionof the site.
2.2 Description
Providingaccesstoextensive shoppinganddiningexperiencesforthe surroundingcommunity,
Dobsonwill be constructedas an arterial roadfor the site containingtwolanesineachdirection,a
centerturninglane,andpedestriansidewalks.The bridge willbe asingle spanof 115 feet,asany
additional spanswould require piers tobe constructedwhichwouldcause anobstructionof the canal.
2.3 Design & Building Codes
In orderto assure the safe and effective use of the proposed bridgesovertheirexpected lifetimeof
50 to 100 years, several designcodesmustbe usedfordesignandanalysis.These codesinclude:
 AASHTO LRFD 2012 Bridge Design Specifications – 6th Edition
 PCI Bridge Design Manual – 3rd Edition
 Arizona Department of Transportation Bridge Group Design Guidelines
3.0 Site Conditions
3.1 Site and Bridge Location
The locationof the proposedbridge canbe seeninthe proposedlanduse planinfigure one on
the nextpage.

5. 5
Figure 1: Site and Bridge Location
3.2 Existing Conditions
The site currentlyconsistsof three dirtroads,one on eitherside of the canal andDobsonRoad
whichisto be turnedintoa minorarterial road.The majorityof the land to the northof the canal has a
lowgrade droppingonly18 feetfromTalkingStickWayto the edge of the canal, thoughthere isa much
steeperslope of roughly 5percentapproachingwhere the proposedbridge istobe constructed. Onthe
southside of the canal, the landisvirtuallyflatthroughout. Relevantsoilpropertiesusedinthe
determinationof the footingsandabutments canbe foundinthe geotechnical report.
4.0 Preliminary Bridge Designs
4.1 Bridge Geometry Alternative #1
The firstbridge design consistsof sevenpre-castpre-stressedBT-72AASHTO-PCIbulb-tee
beamsspacedat twelve feet.These beamswill supportanine inchcast inplace deckspanning115 feet
fromabutmentto abutment. The deckwill consistof five twelve footlanes,twofootshoulders,fivefoot
sidewalks,andone-foot-wide parapets.A typical cross-sectionforthisdesigncanbe seen onthe next
page in figure two,withatypical beamcross sectioninfigure four.

6. 6
Figure 2: Typical Cross Section Alternative #1
4.2 Bridge Geometry Alternative #2
The secondbridge designconsistsof eightcustomsteelI-beams,shownif figure four, spacedat
tenfeet.These beamswill supportaneightanda half inchcast inplace deckspanning115 feetfrom
abutmenttoabutment.The deckwill consistof five twelve footlanes,twofootshoulders,five foot
sidewalks,andone-foot-wide parapets.A typical cross-sectionforthisdesigncanbe seenbelow in
figure three.All dimensionsnotshowninfigure three are assumedtobe identical tofigure two.
Figure 3: Typical Cross Section Alternative #2
Figure 4: Steel (left) & Concrete (right) Beams
4.3 Bridge Superstructure Alternative #1
A pre-castpre-stressedsuperstructure designwaschosenforitsease of assembly,lowinitial
cost, andlowmaintenance.Startingwithaknownspanof 115 feetthe PCIBridge Design Manual was
usedto selectthe mosteconomical option fromall the pre-stressedbeams.Figure five showsan

7. 7
example of the chartsusedto selectthe size,spacing,andstrandsof the beams,alongwiththe cost
assessmentshown intable one.
Figure 5: Beam Girder Selection Chart
Table 1: Cost Comparison of Pre-Stressed Beams
Beam
Type
Beam
Spacing
(ft)
Number
of
Beams
Widt
h (ft)
Number
of
Strands
Area
(cubic
yards)
Price
Per
Girder
Price of
Strands
Deck
Thicknes
s (in)
Deck
Area
(Cubic
Yards)
Cost
of
Deck
Total
Cost
BIV-48 4 17 68 29 25 2243 1091 6 128 11500 51357
BIII-48 4 17 68 33 24 2163 1241 6 128 11500 50150
BIV-36 3 22 66 25 21 1891 1217 6 128 11500 54966
BT-54 6 12 70 30 19 1754 797 8 170 15333 37820
BT-63 6 12 70 26 21 1898 690 8 170 15333 39439
BT-72 6 12 70 22 23 2042 584 8 170 15333 41058
BT-72 8 9 68 32 23 2042 637 8 170 15333 34985
BT-72 10 8 74 36 23 2042 637 8 170 15333 32944
DBT-2 5 12 66 24 30 2670 637 0 0 0 33316
DBT-2 4 15 68 28 28 2478 929 0 0 0 38744
Type IV 6 12 68 34 23 2100 903 8 170 15333 42079
Type IV 8 9 66 38 23 2100 757 8 170 15333 35632
Type V 6 12 70 28 30 2697 743 8 170 15333 49075
Type V 8 9 68 38 30 2697 757 8 170 15333 40999
Type V 10 8 74 44 30 2697 779 8 170 15333 38324
Type V 12 7 76 42 30 2697 651 9 192 17250 37416
Type VI 6 12 70 24 32 2888 637 8 170 15333 51269

8. 8
As seenin table one,the BT-72 beamwastiedfor the fewestbeamsneededdue the large
twelve-footspacing.However,itbeatoutthe Type V andType VIbeamsbyrequiringlessreinforcing
strandsand havinga smallercross-section. Table 6.5.2.3-1of the PCIBridge DesignManual was usedin
orderto determine the cast-in-place deckthicknessof nine incheswhichresultedfromthe twelve-foot
spacing.The designtablesalsoaccountedfora half inchreductioninthe slabto account fora future
wearingsurface complyingwith9.7.1.1of the ADOTBridge DesignGuidelines.
4.3.1 Bridge Loading Alternative #1
The firstloadsto be consideredare the deadandlive loadsappliedtothe deck.ADOTBridge
DesignGuidelinesspecifythata stripanalysismust be usedfordeadloadsusingthe simplifiedmoment
equation 10/2
wS withSbeingthe effective length,stay-in-place formswill have aweightof 0.012 kips
persquare foot,and that un-factoredlive loadmomentswill be takenfromAppendix A4.1of the
AASHTOLRFD Bridge DesignSpecifications.The calculationsof the reinforcementscanbe foundin
Appendix A.1.1.
Loads actingon the beamgirdersare evaluatednext.Section6.5.2.2 of the PCI Bridge Design
Manual assumesthathalf of a 0.5 ksf barrierrail loadiscarried byboth the exteriorandfirstinterior
beam.Thisassumptionwasmade by assumingheavyparapetloads,stiff beams,andshortoverhangs,
whichholdstrue forthisdesign.Furtheranalysisof deadloadsisrequiredhowever,andiscarriedoutin
accordance with3.5.1 of AASHTOLRFD Bridge DesignSpecifications.Section3.6.1 of the ADOT bridge
guidelinesspecifythatall bridgesmustbe designedtohandle atleastHS-20-44 trafficloading,which
calculatesthe momentsassumingasimple span.The designtruck loadingand momentcanbe seenin
figure six andsevenrespectively,withthe restof the calculationsdetailedinAppendixA.1.2.
Figure 6: Loads Used to Calculate Design Truck Moment

9. 9
Figure 7: Design Truck Moment
Live loaddistributionaccordingtoAASHTOLRFD4.6.2.2.1-1 must be analyzednext.Forthis
beamdesign, Type (k) crosssectionfromtable 4.6.2.2.1-1 was selected.Detailsof thiscalculationare
showninAppendix A.Withall of these loadsaccountedfor,the loadcombinationlimitstatesaccording
to AASHTOLRFD Table 3.4.1-1 can be calculatedasshownbelow intable two,whichdetailsall the loads
whichare evenlydistributedalongthe spanof the bridge,withthe correspondingshearandmoments
calculatedinAppendixA.1.2.
TABLE 2: ALTERNATIVE #1 DISTRIBUTED LOADS (K-FT)
LIMIT STATE DC Non-
Composite
DC Composite DW Lane Load Sidewalk
STRENGTH I 2.36 0.25 0.27 0.64 0.075
LOAD FACTOR 1.25 1.25 1.5 1.75 1.75
TOTAL 4.92
SERVICE II 2.36 0.25 0.27 0.64 0.075
LOAD FACTOR 1.0 1.0 1.0 1.0 1.0
TOTAL 3.60

10. 10
4.4 Bridge Superstructure Alternative #2
A steel superstructuredesignwaschosenforthe secondalternativesince afairlyin-depthcost
analysisof all of the commonpre-stressedconcrete beamswasdone forthe firstalternative.Itwas
decidedthatsteel wouldbe usedforthe seconddesignin ordertodetermine if adifferentmaterial
wouldbe cheaperthanthe concrete route.The I-beamsectionwasdeterminedbyfollowingthe
standardsestablishedinthe AASHTOLRFDBridge DesignSpecificationswhichdictatedwebdepth
(2.5.2.6.3), webthickness(6.10.2.1),andflange geometries(6.10.2.2).
4.4.1 Bridge Loading Alternative #2
Once again,the firstloadstobe consideredare the deadandlive loadsappliedtothe deck.
ADOT Bridge DesignGuidelinesspecifythatastripanalysiswill be usedfordeadloadsusingthe
simplifiedmomentequation 10/2
wS withSbeingthe effective length,stay-in-place formswill have a
weightof 0.012 kipsper square foot,andthat un-factoredlive loadmomentswill be takenfrom
Appendix A4.1of the AASHTOLRFD Bridge DesignSpecifications.The calculationsof the reinforcements
can be foundinAppendixA.1.1.
Loads actingon the beamgirdersare evaluatednext.These loadsare analyzedinaccordance
with3.5.1 of AASHTOLRFD Bridge DesignSpecificationsconsideringStrengthIandService IIandare
detailedintable twobelow. Exactly likealternativeone, Section3.6.1of the ADOT bridge guidelines
specifythatall bridgesmustbe designedtohandle atleastHS-20-44 trafficloading,whichcalculatesthe
momentsassumingasimple span.The designtruckmoment willbe the same forboth alternativesand
can be seeninfigure seven,withthe restof the calculationsdetailedinAppendixA.1.3.
Live loaddistributionaccordingtoAASHTOLRFD4.6.2.2.1-1 must be analyzednext.Forthis
alternative Type (a) crosssectionfromtable 4.6.2.2.1-1 wasselected.Detailsof thiscalculationare
showninAppendix A.Withall of these loadsaccountedfor,the loadcombinationlimitstatesaccording
to AASHTOLRFD Table 3.4.1-1 can be calculated fromthe values shownbelow intable two,which
detailsall the loadswhichare evenlydistributedalongthe spanof the bridge,withthe corresponding
shearand moment calculations inAppendix A.1.2.
TABLE 3: ALTERNATIVE #2 DISTRIBUTED LOADS (K-FT)
LIMIT STATE DC 1 DC 2 DW Lane Load WL
STRENGTH I 1.51 1.73 0.2 0.64 0.05
LOAD FACTOR 1.25 1.25 1.5 1.75 0
TOTAL 4.35
SERVICE II 1.51 1.73 0.2 0.64 0.05
LOAD FACTOR 1.0 1.0 1.0 1.0 0
TOTAL 3.44
4.5 Additional Considerations
ADOT guidelineswouldcall forthe calculationof the numberof reinforcingstrands ineach
beamgirderfor alternative one,howeverthisstepwill be disregardedsince the PCIdesignchartswere

11. 11
used,providingthe numberof strandsneeded.Section6.5.2and 6.6.4 of the PCIBridge DesignManual
detail the criteriaandcontrols to which the designcharts were developed.Calculationsthatwould
normallybe carriedoutaccordingto the ADOTprocessare assumedtobe safe due tothe following
considerationsincorporatedintothe designchartsused:
Trial designswere performedbyPCIon bothexteriorandfirstinteriorbeamswithastandard
overhangof three andhalf feetfromthe centerline of the exteriorbeam.Thisisafar greaterdistance
than the overhangof twofeetinthisdesignsuggestingoverhangdesignconsideredinAASHTOLRFD
A13.4.1 issafe. Each charts maximumspanwasdeterminedbysatisfyingthe StrengthIandService III
limitstates,orwhennofurther strandscouldbe addedto the section.Inorderto control the high
stressesassociatedwiththe transferregions,harpinghelddownattwofifthsthe lengthof the beam,or
de-bondingwasused.
4.6 Bridge Substructure
Abutmentsonspreadfootingsasseeninfigure eight will be usedtosupportthe superstructure
of bothbridge alternatives. The onlydifferencebetweenthe alternativesis the backwall supportingthe
superstructure isshorterforthe secondalternative since the superstructure isshorter,withall other
dimensionbeingidentical.These substructurescanalsobe seeninthe profile andplanviewsof each
alternative infigure nine andtenrespectively.Eachsubstructure wasanalyzedtowithstandthe failure
conditionsof bearingresistance,settlement,slidingresistance,andoverturning,detailedinAppendix
A.2. withthe table of rightingmomentsforthe northabutmentseenintable fourbelow.
TABLE 4: RIGHTING MOMENTS FOR NORTH ABUTMENT
COMPONENT Back
wall
Seat Seat Stem Footing End
Block
End
Block
Wing Toe
Soil
Heel
Soil
Total
WEIGHT (K/FT) 1.06 0.15 0.075 7.99 8.4 1.91 7.40 6.09 5.36 18.88 54.12
MOMENT ARM (FT) 9 10 9.83 7.5 8 7 7 10.75 2.75 12.75
RIGHTING MOMENT
(FT-K/FT)
9.51 1.5 0.74 59.96 67.2 13.39 51.80 65.56 14.75 240.76 493.00

12. 12
Figure 8: Abutment on Spread Footing for Alternative #1 (Left) Alternative #2 (Right)
Figure 9: Profile Views of Alternative #1 (Top) & Alternative #2 (Bottom)

13. 13
4.7 Deck Drainage
Both alternativeswere designedwithatwopercentcrowninthe middle of the roadway as seen
infigurestwoand three, anda slope of one percentfromnorthto south (lefttoright) as seeninfigure
nine.Thiswill allow watertoflowawayfromthe centerof the roadwaytowardthe shouldersandoff of
the bridge entirelyatthe south (right) endasseeninthe planview infigure nine,whichisidentical for
bothalternatives.
Figure 10: Plan View of Both Alternatives
5.0 Construction ProceduresandAesthetics
5.1 Alternative #1
Footings and abutments must be constructed first in order to facilitate the placement of
the superstructure beams. For this design only minor excavation would be necessary, followed
by placing reinforcing steel, and finally placing and curing the concrete. Placing the precast pre-
stressed beams is an extremely quick process as all of the beams are manufactured off-site and
only need to be placed onto the abutments and secured. This off-site manufacture also allows
the builders to neglect weather conditions during the placing of the beams as no curing is
needed. Reinforcing steel and stay-in-place forms for the deck would be placed followed by the
pouring and curing of the concrete. To finish the construction, the precast combined sidewalk,
parapet, and railing would be placed onto the deck.
The aesthetics of precast concrete are very versatile due to the off-site manufacture of
the beams. Nearly any color could be chosen to liven up a design meant to appear as masonry,
or perhaps Arizona wildlife on the exterior of the beams, and parapet walls.
5.2 Alternative #2
The construction of the second alternative would be very similar to the first with one
major change. After the construction of the footings and abutments, the steel beams and cross-

14. 14
frames would need to either be welded or bolted into place. With upwards of 200 individual
steel members this process would be much longer than the concrete option. With the beams
and cross-frames in place the deck could be poured, followed by placing the sidewalk, parapet,
and railing as in the first alternative.
Aesthetic options for steel bridges are much more limited than precast concrete as they
can only be painted. However, the exterior parapet walls could still bear a design of masonry or
wildlife as in the first alternative, though it would a much smaller design, being only three feet
tall as opposed to almost ten feet.
6.0 Cost Comparison
6.1 Alternative #1
In order to develop a cost comparison for both alternatives the prices per unit of
measurement of a material was found followed by the amount of that material for each
alternative. The first alternative included concrete, rebar, steel strands, concrete forms,
paint/pigmentation, excavation, and stamping for aesthetic designs. These cost are tabulated in
table four. In addition to these cost, the cost of construction would be lower than the second
alternative due to the ease of placing the precast pre-stressed beams.
6.1 Alternative #2
Materials used for the second alternative, with cost tabulated in table four include;
concrete, structural steel, rebar, concrete forms, paint/pigmentation, excavation, and stamping
for aesthetic designs. Though the concrete cost of the second alternative is much lower than
the first, the cost of structural steel and the assembly of said steel is much greater.
TABLE 5: COST COMPARISON OF ALTERNATIVES
Cost Per
Unit
Unit Units Alt. #1 Units Alt.
#2
Total Per Alt. #1 Total Per Alt. #2
DECK CONCRETE
$265
3
yd 242.78 229.29 $64336.7 $60761.85
GIRDER CONCRETE
$50
3
yd 158.83 0 $7941.5 $0
STRUCTURAL STEEL $0.54 lb 0 268627 $0 $145058.6
REBAR $0.75 ft 25120 25120 $18840 $18840
STRANDS $0.74 lb 711.62 0 $526.5988 $0
FORMS $1.75 2
ft 6555.06 6190.83 $11471.355 $10833.95
PAINT/PIGMENT $6 2
ft 1725 4405 $10350 $26430
EXCAVATION $6.5 3
yd 1020.59 1020.59 $6633.84 $6633.84
ABUTMENT $93 3
yd 9950 9713 $925350 $903309
STAMPING $12 2
ft 1725 690 $20700 $8280
GRAND TOTAL $1,066,149.99 $1,180,147.00

15. 15
7.0 Sustainability
Precast concrete bridges are inherently sustainable, as they have a service life of 100
years or more requiring very little maintenance, and due to off-site manufacture reduce the
environmental impact at the construction site. Precast concrete is also frequently built using
recycled materials and can be recycled at the end of its service life.
In order to advance the sustainability of the proposed bridge even further, a water
collection basin could be used at the south of the bridge to collect rainwater that would go to
waste otherwise. Due to the drainage design of the bridge, all the water would flow from each
shoulder to the south end of the bridge where two catch basins could harvest rain water. With
an average of 9.4 inches of rain per year at the site, over 51,000 gallons of water per year could
be collected from the drainage of the bridge. This water could be used to irrigate the
agriculture parcel of the site, and with an average crop needing 27,160 gallons of water per
acre per year, the collected water would equal about one inch of annual rainfall for nearly two
acres of land. As in any desert environment, it is crucial to waste as little water as possible. Even
though the water collected would only be able to facilitate just over 3% of the agriculture
parcel for a year, every drop counts.
8.0 Conclusion
When comparing the alternatives, it is clear that the precast pre-stressed concrete
option is far superior. Looking purely at the cost comparison from table four which only takes
into consideration the materials of the project, a savings of $113,997.20 is found. This cost
comparison does not factor in the cost of construction which is predicted to be smaller than the
steel option, as far less welding and bolting of members is required, although the pre-cast
option would require a crane with a higher lifting capacity.
Maintenance cost over the life cycle of the bridge was another factor not considered
which should also be much lower for concrete, as steel is much more vulnerable to the
elements and requires frequent painting in order to protect it from said elements. All things
considered a precast bridge will save money and last longer than the steel option making it the
preferred alternative for Talking Stick Plaza.

16. 16
Appendix A.1 SuperstructureLoadCalculations
A.1.1 Preferred Alternative Deck Loads

17. 17

18. 18
A.1.2 Preferred Alternative Superstructure Loads

19. 19
A.1.3 Preferred Alternative Live Loads

20. 20
Appendix A.2 SubstructureCalculations
A.2.1 Preferred Alternative Foundation Calculations

21. 21

22. 22

23. 23
Appendix B Project ValidationForm