Engineers Club Of Memphis V2

Structure Type Studies for
Local Infrastructure Managers

Engineers Club of Memphis

8.22.2011

U.S. Bridge
 History
 Working Together
 Engineering Case Study
 Project Profiles

Engineers Club of Memphis - 8.22.2011

U.S. Bridge

U.S. Bridge has been Bridging America for 75
years. Since 1936 we have been
manufacturing bridges in the United States
with the highest regard for our customers
needs and quality of our work. As the largest
manufacturer pre-fabricated steel truss
bridges in the United States, we remain the
trusted leader in the industry.


History
 Founded as
American
Culvert in 1936
by brothers
Herman & Ted
Rogovin


History
 Designing & Building Truss
Bridges for over 60 years


Location
 Cambridge, Ohio
 Juncture of I-70 & I77
 21 shops covering
250,000 sq ft. in 11
buildings


How we work with you
 Feasibility Assessments
 Programming Costs
 Specifications & Schematic
Details
 Preliminary Engineering
 Modeling & Rendering


How we work with you …
 Hard Bid Quotes & Information
 Engineering Design & Plan Submittals
 Construction Submittals


How we work with you …
 On-Site
Installation
Assistance


Structure Type Study Reference Paper


Purpose of the Paper
 To give local infrastructure managers a guide and
reference to use when scoping and evaluating a site
for a bridge project.
 Ensures all costs and factors are
considered, including life cycle costs.
 Real world sites and examples.
 First of a 3 Part Series. Eventually 2 more sites will
be investigated.


Why was THIS bridge built
here?


Existing Site, Bridge & Conditions
 Situated in a low-land area
 Rural character (narrow 10 ft. lanes, no shoulders)
 Low Volume ~ 350 vehicles per day (vpd)
 Loosely consolidated sandy-silt, silt and clay
 Bedrock not encountered in the soil borings
 Existing 3-span beam bridge (simple spans)
 Steel floor with asphalt fill and wearing surface
 Frame-bent piers from steel caps on piles
 Built as a temporary structure 30 years prior
 Bridge in poor condition and closed


Hydraulic Conditions
 Channel was wooded & unmaintained
 Woody debris on the piers a maintenance problem
 Flooding of approach roadways
 Flood level at, or nearly at low-steel elevation
 Channel was constricting, as velocities through
channel were 5x greater than up- or downstream


Existing bridge


Utilities

Surrounding low land

Rural roadway & character

Farm drive


DETOURED! Subsurface Conditions


Wooded area Entrenched stream

Woody debris


What goes into Scoping a project
 What’s important to consider?
 Funding strings? or no funding strings?
 What are the goals of the project?
 How easy is it going to be to build?
 Maintenance - What am I going to be stuck
with?
 How long will this bridge be here?
 What else is important?


Goals for the Project
 Provide adequate bridge width for facility
 Provide adequate span to allow hydraulic clearance
 Minimized impacts to profile grade
 Minimized in-stream work
 Minimize impacted R/W & construction footprints
 Minimize detour (closure duration)
 Minimize adjacent road damage
 Minimize construction risk
 Minimize construction costs


Scope of Proposed Work
 Projected Traffic: 500 vpd.
 Bridge Width: 11ft lanes plus 4 ft shoulders = 30 ft rail/rail
 Approach slabs, guardrail, embankment & pavement
 Design Year Flood: 10-year, Low steel = EL 1028.0 ft
 Ordinary High Water (OHW) = EL 1024.0 ft.
 Increase hyd. opening using 2:1 slopes & spill-thru
abutments
 Deep foundations using friction resistance CIP/steel pipe
piles
 Over-the-side drainage with splash guards
 120 ft. (+/- ) span range
 New rock channel protection along end slopes & aprons
 Taper improvements into existing Engineers Club of Memphis - 8.22.2011

What’s left?
 Alternates of span configurations?
 Alternates of structure types?


Remaining Variables
 Structure Depth
 Profile Grade
 Impacted Footprint
Proposed Span ~ 120 ft

Exist Span = 90 ft (+/-)

STRUCTURE DEPTH

100-year EL = 1029.6
OHW EL = 1024.0
10-year EL = 1028.0
Normal EL = 1020.0


Case Study No. 1
 Structure Type Study Narrative (21
Pages)
 Alternate Descriptions
 Life Cycle Cost Analysis
 Evaluation Matrix
 Evaluation of Alternatives
 Evaluation of NPV of Alternatives
 Conclusion & Summary
 6 Appendices with drawings, cost
estimates, etc.


Alternatives
 Alt. 1 – 3-Span, Cast-in-Place Slab
 Alt. 2 – Single Span, P/S AASHTO Girders
 Alt. 3 – Single Span, Steel Low (Pony) Truss
 Alt. 4 – 3-Span, Composite P/S Concrete Box
Beams


Basis for Comparisons
 Initial Construction
 Engineering costs (15% of construction)
 Roadway pay items (Appendices A & B)
 Bridge pay items (Appendices A & B)
 Right-of-way costs


Basis for Comparisons
 Life Cycle Costs
 Initial cost to construct
 Annual maintenance and inspections
 Annual work activities
 Minor rehabilitation projects (20 years)
 Major rehabilitation projects (50 years)
 Residual Values
 Net Present Value (NPV)


Annual Work Activities

 Debris Removal
 Bridge Inspection


10 Year Work Activities

 Silane Sealer
 Light Patching


50 Year Work Activities

 Deck slab replacement
 Deck edge replacement
 Superstructure replacement
or reconditioning


… and also qualitative measures

 Temporary construction
 Environmental permitting
 Ease of delivery
 Construction equipment


Life Cycle Costs: Net Present Values

 Cost basis = 2002 State Bid Tabulations
 Design Life Term = 75 years
 Interval timeline = 10 years; 20 years; 50 years
 Inflation (2002 – 2010) = 135%
 Discount rate = 2.7% per year
n

NPV = Σ RCFt / (1+i)t
t=0
to calculate NPV:
where:
RCFt = Real Cash Flow
i = Annual Discount Rate
n = term

#1 3-Span Concrete Slab Bridge
 36 ft - 45 ft - 36 ft spans c/c of bearings
 Bridge Limits = 118.3 ft
 Project Limits = 450 ft
 Structure depth = 2.07 ft (Slab thickness = 22 in.)
 Profile grade impacts: similar to existing
 Engineering = $113,000
 Construction = $753,000
 Maintenance: 7 projects in 75 yrs @ $1,332,800
 Life Cycle Costs (NPV) = $1,124,115


#1 3-Span Concrete Slab Bridge


#1 – Three Span Concrete Slab Bridge


#2 Single Span Prestressed I-Beam Bridge
 114 ft span c/c of bearings
 Project Limits = 1,350 ft
 Structure depth = 7.07 ft (AASHTO Type IV = 72 in.)
 Profile grade impacts: +3.3 ft


#2 Single Span Prestressed I-Beam Bridge


#3 Single Span Steel Half-Through Truss
 116 ft span c/c of bearings
 Structure depth = 3.56 ft (W30 FB + 10 ½” Slab)


#3 Single Span Steel Half-Through Truss


#4 3-Span Composite Box Beam Bridge
 36 ft - 45 ft - 36 ft spans c/c of bearings
 Structure depth = 2.16 ft (CB17 + 6” Topping)


#4 3-Span Composite Box Beam Bridge


Comparison Matrix
Comparisons Alternate 1 Alternate 2 Alternate 3 Alternate 4
(3-Span (1-Span (1-Span Steel Half (3-Span Comp.
CIP Slab) P/S Girder) Truss, DOT) Box Beam)

Construction
$876,000 $1,143,000 $949,400 $848,400
Cost
(3.2%) (34.7%) (11.9%) (0.0%)
(+/- % Min.)

Life Cycle Cost $1,124,000 $1,432,000 $1,212,000 $1,189,000
(+/- % Min.) (0.0%) (27.4%) (7.8%) (5.8%)

Total Cost/
$247/sf $325 /sf $264 /sf $239 /sf
SF of Bridge

Spans: 3 spans 1 span 1 span 3 spans
Bridge Limits: 118.32 ft 117.16 ft 120.0 ft 118.50 ft
Work Limits: 450 ft 1,350 ft 450 ft 450 ft

Embankment
0.07 ft 3.35 ft -0.09 ft 0.07 ft
Rise


Comparison Matrix, cont’d
Comparisons Alternate 1 Alternate 2 Alternate 3 Alternate 4
(3-Span (1-Span (1-Span Steel Half (3-Span Box
CIP Slab) P/S Girder) Truss, DOT) Beam)

Hydraulic
Clearance 1.9 ft 0.3 ft 0.3 ft 1.8 ft
(10 yr flood)

Substructure
4 2 2 4
Units

Deep 4,680 ft 5,760 ft 3,960 ft 4,770 ft
Foundations Driven Driven Driven Driven

Environmental ACOE 404 Permit ACOE 404 temp. ACOE 404 Permit
No work in stream
Impacts for pier const. work area for pier const.

Strip take on 2
R/W Strip take on 1 side Strip take on 1 side Strip take on 1 side
sides (embank &
Impacts (ditch) (ditch) (ditch)
ditch)


Comparison Matrix, cont’d
Construction Alternate 1 Alternate 2 Alternate 3 Alternate 4
Comparisons (3-Span (1-Span (1-Span Steel Half (3-Span Box
CIP Slab) P/S Girder) Truss, DOT) Beam)

Work area for lifting
Temporary Causeway Causeway to
beams none
Works or Areas & form shoring construct piers
(60T ea.)

Flood Risk
High Medium Low Medium
during Const.

Utilities n/a n/a n/a n/a

Equipment 500T Crane; 250T Crane; 250T Crane;
Concrete pump
Needed Concrete pump Concrete pump Concrete pump

In-stream piers are
In-stream piers are Delivery of long Smaller crane lifts;
Other susceptible to
susceptible to beams; road crane lifts from
Factors debris; smaller
debris damage roadway
crane lifts


Conclusions
 Based on the owner preference for a clear-span
bridge, the lowest cost one-span bridge is the steel
low-truss bridge. This is, in fact, what the owner
selected, and the structure was constructed in 2002.
 The premium to do the selected alternative over
least cost alternative is $101,000 (initial costs) which
is reduced over time to a Net Present Value premium
of only $23,000 (75 years).


PROJECT PROFILE
Owner: Shelby County, TN
Route: Bass Rd.
Contract Docs: Shelby
County, TN
Contractor: Shelby County
Roads & Bridges
Bridge Contractor:U.S. Bridge
Style: Hybrid Cambridge /
Seneca
Floor Framing: Raised

Connections: Welded
Span: 70 ft.
Width: 32 ft.
Finish: Painted
Floor/Deck: Concrete
Railing: W-Beam

Bass Rd. Shelby County, TN

PROJECT PROFILE
Route: Kenville-Rosemark
Rd.
County, TN
Roads & Bridges
Seneca

Connections: Welded
Span: 60 ft.
Width: 40 ft.
Finish: Painted
Railing: W-Beam

Kenville-Rosemark Rd., Shelby County, TN

PROJECT PROFILE
Route: Sycamore Rd.
County, TN
Roads & Bridges
Seneca

Connections: Welded
Span: 55 ft.
Width: 30 ft.
Finish: Painted
Railing: W-Beam

Sycamore Rd., Shelby County, TN

Lunch and Learn Presentations Available:

Prefabricated Steel Truss Bridges

Historical Bridge Rehabilitation

Steel Truss Bridge Rehabilitation


Geometry & Description – Bridge Styles

Cortez Beam Bridge 1 Cambridge Flat 1

Cambridge 2 Viking 4

Cost Scale
__________________________________ 5
Seneca 1 3
4 Thru-Truss 3
Least Expensive Most Expensive

Geometry and Description - Finishes

Weathering

Painted

Weathering
Galvanized

Galvanized & Painted Galvanized Weathering Painted
Galvanized

Accessories - Railing Systems

Guard Rail Systems Type

Independent Rail System

Independent Rail Attached to
Stringer
W Beam with Bracket
Attached to Truss

W Beam Attached Directly to Truss Truss Mounted Rail System

Accessories – Approach Railing

Approach Rails Yes or No

W Beam to Thrie Beam to Tubular
Railing

Thrie Beam Transition to
Tubular Rail

Thrie Beam Transition
Thrie Beam Transition to Tubular Rail
to Tubular Rail
W Beam Flared End

Thank you for your time.

Engineers Club of Memphis

8.22.2011

Engineers Club Of Memphis V2

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