seafarer's center pedestrian bridge
TRANSCRIPT
SEAFARER’S CENTER PEDESTRIAN BRIDGE
Mah-rukh Muhammad, Project Engineering Intern
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PROJECT: SEAFARER’S CENTER PEDESTRIAN BRIDGE
By Mah-rukh Muhammad
What: Pedestrian bridge, foundation, piers
Location: Adjacent to drainage ditch linking the executive
building to the Seafarer’s Center
Manage:
o Scope development
o Research
o Cost estimating
o Surveying
o Proposal preparation
Utilize
o C=Constructability
o A=Availability
o M=Maintainability
o E=Environmental
o O=Operations
o S=Security
o S=Safety
Create:
o Competitive sealed bids for the fabrication, delivery, and
erection of the bridge
o Competitive sealed bids for the construction of the bridge
foundation
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Table of Contents PROJECT PLAN: ................................................................................................................................................................................... 3
CAMEOSSS .......................................................................................................................................................................................... 5
PROJECT EXECUTION .......................................................................................................................................................................... 6
Optimal Routes .............................................................................................................................................................................. 6
Narrow Down Routes .................................................................................................................................................................... 7
Option 1..................................................................................................................................................................................... 8
Option 2..................................................................................................................................................................................... 9
Aerial Photo ............................................................................................................................................................................ 10
Bridge Design Considerations ..................................................................................................................................................... 11
Material Properties ..................................................................................................................................................................... 12
Painted Steel ........................................................................................................................................................................... 12
Aluminum................................................................................................................................................................................ 13
Galvanized Steel...................................................................................................................................................................... 14
Weathering Steel .................................................................................................................................................................... 15
Design Build Cost Estimates ........................................................................................................................................................ 16
Bridge Material Recommendation ............................................................................................................................................. 17
Materials Matrix ..................................................................................................................................................................... 17
Aluminum Versus Steel Life Cycle Cost .................................................................................................................................. 18
Decking Material ......................................................................................................................................................................... 21
Maximum Span Reactions........................................................................................................................................................... 23
28 Feet Bridge ......................................................................................................................................................................... 24
60 Feet Bridge ......................................................................................................................................................................... 25
Bridge Option Decision................................................................................................................................................................ 26
Foundation Design....................................................................................................................................................................... 27
Anchorbolt Design ....................................................................................................................................................................... 32
CAD Drawings .............................................................................................................................................................................. 34
Abutment Detail ..................................................................................................................................................................... 34
Bridge Location Drawing ........................................................................................................................................................ 35
Bridge and Foundation General Drawing .............................................................................................................................. 36
Bridge Profile .......................................................................................................................................................................... 37
Foundation Profile .................................................................................................................................................................. 38
Result: ............................................................................................................................................................................................... 39
References: ....................................................................................................................................................................................... 40
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PROJECT PLAN:
1. Find the optimal locations for the bridge pathway a. Study various routes
i. Map, AutoCAD, Google Earth ii. field visit
b. Speak with CAMEOSS Team about the best route for employees to take
c. Finalize the best routes and bridge locations down to three 2. Narrow options down to two
a. Option 1: wide end b. Option 2: narrow end c. Rule out third option by creating a Matrix
3. Find the length and width of both bridge options a. Contact Survey Department and make appointment to
survey the area. b. Point out the optimum locations to ensure survey accuracy
4. Research material properties:
a. Find information about the material b. Create an advantages and disadvantages table for each
material c. Factor:
i. Cost ii. Sustainability
iii. Maintenance iv. Reliability v. Safety
5. Contact Bridge Fabrication and Erection Companies and find out the cost of both options for each material
6. Analyze the costs and the material properties to recommend bridge material
a. Create a materials matrix
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7. Analyze decking material options a. Decking material advantages and disadvantages b. Decking material costs c. Create decking material matrix to recommend a decking
material 8. Meet with CAMEOSS team to analyze Option 1 and Option 2
a. Address any project concerns at this point 9. Find out the dead, live, and uplift weight loading of that material
and analyze geotechnical properties of the area and foundation 10. Meet with PCM team to present both bridge options and narrow
it down to one option 11. Design foundation with the data accumulated
a. Utilize Klotz and Associates design program i. Foundation includes piers, abutment cap, backwall
12. Design anchorbolts using the Brown and Root Design Guide 13. Create all bridge and foundation drawings in AutoCAD
a. Abutment Detail b. Bridge Location Drawing c. Bridge and Foundation General Drawing d. Bridge Profile e. Foundation Profile
14. Create Specification Documents a. Bridge b. Drilled Pier c. Excavation d. Hydromulching e. Safety f. Mobilization and demobilization g. Storm water control
15. Create bid packet for that option. Bid packet must include: a. Bridge b. Foundation
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CAMEOSSS
Constructability o Material o Foundation o Bridge construction company
Availability o Power o Location o Foundation
Maintainability o Maintenance issues in material
Environmental o Investigate on if it meets environmental compliance
Operations o Time frame o What needs to be done o Who will do it
Security o Make sure that the bridge is secure
Safety o Effective lighting o Safe with heavy loads o Nearby emergency exit
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PROJECT EXECUTION
Optimal Routes
Option 1: Located 112 feet from the bottom of the ditch
Option 2: Located 300 feet from the bottom of the ditch
Option 3: Located 230 feet from the bottom of the ditch
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Narrow Down Routes
SCALE 1 bad
2 medium
3 good
Remaining Options:
Option 1
Option 2
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Option 1
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Option 2
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Aerial Photo
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Bridge Design Considerations
Design consideration factors:
Loading: Pedestrian Traffic
Bridge Foundations must not run into cable installed in the ground
Width:
o The ADA compliant minimum inside clear width is 4 feet, but the actual
width of the bridge will be 5 to 6 feet
o Narrow Bridge Advantages
more efficient load support
less material
minimizes the risk of unintended use (like vehicular traffic)
o Since a narrow bridge is advantageous, we will go with the minimum:
6 feet
Length obtained from survey:
o Option 1: 60 feet
o Option 2: 28 feet
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Material Properties
Painted Steel
Advantages Disadvantages
High strength to weight Weak fire resistance
Strong and flexible Must be repainted Maintenance
Eco-friendly and low waste Brittle fracture
Uniformity Susceptibility to buckling
Ductility a solid material's ability to
deform under tensile stress Fatigue Toughness the ability of a material to
absorb energy and plastically deform without fracturing
Heavy and expensive to transport
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Aluminum
Advantages Disadvantages
Light weight Low bending Low vibration absorption
Low stress capability
Anti-corrosive
High strength to weight ratio
Conductivity
Resilient
Recyclable
Seamless
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Galvanized Steel
Galvanized steel is steel that has been coated with zinc to prevent
corrosion. The steel is submerged in hot, melted zinc, which triggers a
chemical reaction that permanently bonds the zinc and steel together.
During the galvanization process, the steel is first exposed to zinc at a
temperature of approximately 860 degrees. The zinc reacts to available
oxygen in the environment to form zinc oxide, which then forms zinc
carbonate after reacting to carbon dioxide. Iron molecules in the steel react
with the zinc, creating layers of metal that are able to withstand even long
term contact with saltwater.
*In addition to steel advantages and disadvantages on page 10, galvanized
steel provides the following as well:
Advantages Disadvantages
Long life Internal rusting
Low corrosion Unstable joints
Protection at all areas Water contamination
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Weathering Steel
"Weathering" refers to the chemical composition of these steels, allowing them to exhibit increased resistance to atmospheric corrosion compared to other steels. This is because the steel forms a protective layer on its surface under the influence of the weather. The corrosion-retarding effect of the protective layer is produced by the particular distribution and concentration of alloying elements in it. The layer protecting the surface develops and regenerates continuously when subjected to the influence of the weather. In other words, the steel is allowed to rust in order to form the 'protective' coating.
Advantages Disadvantages
Low maintenance
Marine environments
o Weathering steel should
not be used for bridges
within 2km of coastal
water.
Appearance improves with age
Atmospheric Pollution
Weathering steel should not be used in atmospheres where high concentrations of corrosive chemicals or industrial fumes, specifically SO2, are present.
Long Term Performance
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Design Build Cost Estimates
Painted Steel Excel Bridge
60' by 6' cost $53,000
28' by 6' cost $32,000
Aluminum deck Gator Bridge
60' by 6' cost $33,450
28' by 6' cost $18,000
Excel Bridge
Galvanized Steel 60' by 6' cost $68,000
28' by 6' cost $42,000
Weathered Steel Big R Bridge
60' by 6' cost $35,100
28' by 6' cost $17,700
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Bridge Material Recommendation
Weathering steel is no longer an option because:
o It should not be used in atmospheres where high
concentrations of corrosive chemicals or industrial
fumes are present
o It is within 2 K of coastal waters
This leaves the options of:
o Painted Steel
o Aluminum
o Galvanized Steel
Materials Matrix
Materials Matrix Strength
Eco-friendly Flexible
Anti-corrosive
Fire Resistance Maintenance
Ease of Transport Weight Cost SUM
Painted Steel 2 1 1 1 1 1 2 9
Aluminum 1 2 1 2 2 3 2 2 3 18
Galvanized Steel 3 1 3 1 2 1 1 1 13
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Aluminum Versus Steel Life Cycle Cost
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Figure 1 shows the Present Value (PV) for each cost and Total Cost of Ownership (TCO) for each option for a three percent discount rate. Using a three percent discount rate, aluminum has a better TCO than all other steel options by more than $7,000 for an urban environment, and by more than $16,000 for a maritime environment. Aluminum has a TCO equivalent to galvanized steel after 33 years in the urban environment, and after 21 years in the maritime environment. When employing a six percent discount rate, aluminum has a better TCO than all other steel options by more than $4,000 in all maritime and urban environments except Hot-Dip Galvanized in an urban setting; in this case, both aluminum and steel are close to being equal in terms of TOC at the end of 50 years. Aluminum has a TCO equivalent to galvanized steel after 50 years in the urban environment, and after 21 years in the maritime environment.
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The recommended material to be used for the
bridge is aluminum. 1. Cost:
The material cost itself is the least
It has the least total cost of ownership
2. It scored the highest amount of point in the materials
matrix, due to advantageous factors that outweighed
those of the other materials.
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Decking Material
Decking Options:
1. Aluminum
2. Standard Timber Tech Composite Decking
3. Fiber Reinforced Polymer Synthetic Concrete
Aluminum deck Gator Bridge
60' by 6' cost $33,450
28' by 6' cost $18,000
Standard Timber Tech Composite Decking Gator Bridge
60' by 6' cost $36,150
28' by 6' cost $19,260
FRP Synthetic Concrete Gator Bridge
60' by 6' cost $36,870
28' by 6' cost $19,596
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Maintenance, durability, adherence (non-slip surface), and
sustainability should be considered when choosing the
most suitable decking material.
Decking Material Matrix Maintenance Durability Adherence Sustainability Cost SUM
Aluminum deck 3 3 3 3 3 15
Standard Timber Tech Composite Decking 1 1 1 2 2 7
FRP Synthetic Concrete 2 2 2 1 1 8
The recommended decking material is aluminum.
1. Least cost
2. Most points in the decking material matrix
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Maximum Span Reactions
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28 Feet Bridge
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60 Feet Bridge
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Bridge Option Decision
Maximum allowed load according to Geotechnical report:
4500 psf
Load the drill shafts of the 60 foot bridge would have to
resist:
5000 psf
Recommended cause of action:
1. Have geotechnical engineer drill 50 feet, obtain bore
hole, and provide allowable skin friction resistance or
other method to resist 5000 psf
2. Use the 28 foot bridge option
Decision:
To use the 28 foot option
o Less project cost due to the size being half
of the 60 foot
o Cost of geotechnical engineer drilling bore
holes saved
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Foundation Design
Foundation Design Program Viathor Vbent Analysis run on the estimated dimensions to
predict whether it can sustain the maximum loading or not.
Hand calculations done to confirm the Foundation Design Program results as well.
Calculations:
Allowable Load 4500 psf Factor
2
Load at bottom column 31.5 kips Drilled Shaft diameter 2.5 feet Drilled Shaft area
4.908739 ft^2
Abutment Bearing Pressure 6.417127 kips
6417.127 psf
Condition:
reaction dead load 470 lb reaction live load 3780 lb
Total 4250
Abutment cap assumption:
10 feet long
2 feet deep
3 feet wide
Concrete weight
150 pcf
Dead load created by abutment
9000 lbs
Weight Applied to 2 Drill Shafts 17500
*multiply by 2 due to factor of safety
*divide by 2 due to drilled shafts
Sizing
*Assume 30 Inch drilled Shafts
Bearing Pressure
3565.071 psf
Result: Under Allowable
Soil Reduction factor
0.96
New Bearing Pressure 3422.468
*due to spacing
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Pier Diameter
2.5 feet
Pier Length
22-24 feet
Because, as seen in the Bore Log Report above, the soil obtains stiffness at 24 feet
10 inch Backwall
Abuntment Cap
2 feet deep
3 feet wide
10 feet long
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Anchorbolt Design
Anchorbolt Calculations
Wind load 5165 lb/ft
Bridge length 28 ft
Load * length 144620 lb
Approx 140000 lb
Bolts 8
17500 lb
17.5 kip/bolt
Approx 17.4 kip/bolt
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CAD Drawings
Abutment Detail
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Bridge Location Drawing
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Bridge and Foundation General Drawing
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Bridge Profile
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Foundation Profile
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Result:
Bridge: o aluminum bridge and deck o 28 foot bridge, 6 foot clear width
Foundation:
o Piers o Backwall o Abutment cap o Anchorbolts o Grout pad
Final Product: o Drawings created
Abutment Detail Bridge Location Drawing Bridge and Foundation General Drawing Bridge Profile Foundation Profile
o Specifications created Bridge Drilled Pier Excavation Hydromulching Safety Mobilization and demobilization Storm water control
o Bid Package created
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References:
Texas Department of Transportation Geotechnical Manual 2012
Klotz and Associates Vbent Foundation Design Program
COLORADO DEPARTMENT OF TRANSPORTATION BRIDGE DETAIL
MANUAL
Brown and Root Anchorbolt Design
Professional Deck Builder, Designing Pier Footings
Prentice Hall Introduction to Structural Steel Design