Side-by-Side Box Beam Bridge Life-Cycle Cost Analysis For or - - PowerPoint PPT Presentation

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Side-by-Side Box Beam Bridge Life-Cycle Cost Analysis For or - - PowerPoint PPT Presentation

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Side-by-Side Box Beam Bridge Life-Cycle Cost Analysis For or Better Inv nvestment nt and nd Engi ngine neering ng Decisions ons By Nabil Grace, Ph.D., PE Elin Jensen, Ph.D. University Distinguished Professor Associate Professor

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SLIDE 1

Side-by-Side Box Beam Bridge Life-Cycle Cost Analysis

For

  • r Better Inv

nvestment nt and nd Engi ngine neering ng Decisions

  • ns

By Nabil Grace, Ph.D., PE Elin Jensen, Ph.D. University Distinguished Professor Associate Professor Director, Center for Innovative Materials Center (CIMR) Civil Engineering Department Chair, Civil Engineering Department Lawrence Technological University, MI.

US-Japan Workshop Sapporo, Hokkaido, Japan October, 2009 Spo pons nsored by d by Nationa nal Scienc nce Founda undation n

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SLIDE 2

The LCCA Methodology

  • Establish design alternatives
  • Determine activity timing
  • Estimate costs (agency and user)
  • Compute life-cycle costs
  • Analyze the results
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SLIDE 3

Classification of Project LCC

Project Life-Cycle Cost

Agency

Element N New-Material Introduction Element 1 Non- Elemental

Engineers estimate

By Entity that Incurs Cost Level 1 Level 2 By Life-Cycle Cost Category Level 3 By Elemental Breakdown of Project

Construction OM&R Demolition

User

Construction OM&R Demolition

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SLIDE 4

Vehicle Operating Costs = Travel time Costs =

L Sa L Sn −

( ) ×

× ×w

AADT AADT N

L = length of affected roadway over which cars drive; Sa= traffic speed during bridge work activity; Sn= normal traffic speed; AADT = Annual Average Daily Traffic; N = number of days of road work; w = hourly time value of drivers;

L Sa L Sn −

( ) ×

× ×r

AADT AADT N

r = hourly vehicle operating cost;

User Cost

Crash Costs =

× × × × ca

  • An

N AADT AADT L

( )

Aa

Aa = during-construction accident rates per vehicle-mile; An = normal accident rates per vehicle-mile; ca = cost per accident.

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SLIDE 5

The real discount rate (r) r = [(1 + d) / (1 + i)] – 1 = (d – i) / (1 + i ) d – i Where: r = real discount rate, i = inflation rate, d = nominal discount rate (also called interest rate, funding rate)

Inflation and Discounting

≈

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SLIDE 6

LCC Calculations

Ct

t = sum of all costs incurred at time t

r r = real discount rate for converting time t costs T = number of time periods in the analysis period

( )

0 1 T t t t

C LCC r

=

= +

∑

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SLIDE 7

General Plan of Bridge

Cas ase S e Study

46

(SPAN 2) 55 (SPAN 1) 55 110 120 60 60 46

Bridge dimensions are in ft.

15 beams

28 (6) 15mm Ф STRANDS

Dimensions are in inch

(4) A06 BARS 36

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SLIDE 8

Establish Design Alternatives

  • Bridge with black steel reinforcement

and with cathodic protection

  • Bridge with epoxy-coated steel

reinforcement

  • Bridge with CFRP reinforcement
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SLIDE 9

The LCCA Methodology

  • Establish design alternatives
  • Determine activity timing
  • Estimate costs (agency and user)
  • Compute life-cycle costs
  • Analyze the results
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SLIDE 10

Activity Timeline of Black Steel Bridge 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 Year

Construction Deck Patch Beam End Repair Superstructure Replacement Deck Replacement Deck Shallow Overlay Beam Replacement

Determine Activity Timing

Routine inspection every two years Detailed inspection every five years Cathodic protection maintenance every year

Cathodic protection maintenance

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SLIDE 11

Activity Timeline of Epoxy-coated Steel Bridge 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 Year

Construction Deck Patch Beam End Repair Superstructure Replacement Deck Replacement Deck Shallow Overlay Beam Replacement

Determine Activity Timing

Routine inspection every two years Detailed inspection every five years The same activity timing with black steel bridge except cathodic protection activity

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SLIDE 12

Determine Activity Timing

Activity Timeline for CFRP Bridge 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 year

Construction Deck Replacement Deck Shallow Overlay

Detailed inspection every ten years

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SLIDE 13

The LCCA Methodology

  • Establish design alternatives
  • Determine activity timing
  • Estimate costs (agency and user)
  • Compute life-cycle costs
  • Analyze the results
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SLIDE 14

The LCCA Methodology

  • Establish design alternatives
  • Determine activity timing
  • Estimate costs (agency and user)
  • Compute life-cycle costs
  • Analyze the results
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SLIDE 15

Bridge Life-Cycle Cost

$0 $1,000,000 $2,000,000 $3,000,000 $4,000,000 $5,000,000 $6,000,000 $7,000,000 10 20 30 40 50 60 70 80 90 100

Year Life-cycle cost

Black Steel Bridge Epoxy-Coated Steel Bridge CFRP Bridge

5.98 5.63 2.29

Breakeven year

20

Construction Deck Replacement Deck Shallow Overlay Superstructure replacement

Medium span bridge with High-traffic-below and High-traffic-above

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SLIDE 16

Bridge Life-Cycle Cost Comparison

$0.00 $1.00 $2.00 $3.00 $4.00 $5.00 $6.00 $7.00 Life-Cycle Cost (million dollar)

Medium span bridge with High-traffic-below and High-traffic-above

Superstructure Replacement Superstructure Demolition Cathodic Protection Update Cathodic Protection Maintenance Beam Replacement Beam End Repair Deck Replacement Deck Shallow Overlay Deck Patch Detailed Inspection Routine Inspection Initial Cathodic Protection Initial Construction Cost Black Steel Bridge Epoxy-Coated Steel Bridge CFRP Bridge

$0.59 $0.11 $1.85 $1.32 $1.23

5.98

$0.61 $1.03 $1.85 $0.60 $1.32 $0.51 $1.24

5.63 2.29

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SLIDE 17

Sensitivity Analysis

  • Sensitivity analysis studies the manner of

how the most optimal target solution or function (Output), would be affected by changes in the value of one or more parameters (Input) of a model, while the rest of them remain unchanged.

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SLIDE 18
  • Tornado chart shows a graphical

representation of the changes produced in the target optimal solution or function whenever a specific quantity or value in a model’s parameters changes.

Sensitivity Analysis

Tornado chart

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SLIDE 19

Sensitivity Analysis

Tornado Chart of Black Steel Bridge

$5.681 $6.393 $5.511 $6.726 $6.985 $6.235 $5.698 $6.504 $5.344 $5.301 $4.0 $4.5 $5.0 $5.5 $5.98 $6.5 $7.0 AADT below bridge Normal driving speed Sn over bridge Driving speed reduction below bridge Real discount rate Normal driving speed Sn below bridge Life-Cycle Cost (million dollar) parameter -10% parameter +10% Initial value 70 mph 3% 25 mph 100,000

Top 5 sensitive parameters

45 mph

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SLIDE 20

Tornado Chart of Epoxy-Coated Steel Bridge

$5.335 $5.995 $5.165 $6.350 $6.640 $5.889 $5.389 $6.159 $5.025 $4.955 $4.0 $4.5 $5.0 $5.63 $6.0 $6.5 $7.0 AADT below bridge Normal driving speed Sn over bridge Driving speed reduction below bridge Real discount rate Normal driving speed Sn below bridge Life-Cycle Cost (million dollar) parameter -10% parameter +10% Initial value 70 mph 3% 25 mph 100,000

Top 5 sensitive parameters

45 mph

Sensitivity Analysis

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SLIDE 21

Tornado Chart of CFRP Bridge

$2.310 $2.169 $2.104 $2.500 $2.476 $2.175 $2.291 $2.371 $2.048 $2.028 $1.6 $1.8 $2.0

$2.29

$2.4 $2.6 Normal driving speed Sn over bridge Superstructure construction unit cost of traditional bridge Driving speed reduction below bridge Normal driving speed Sn below bridge Real discount rate

Life-Cycle Cost (million dollar) parameter -10% parameter +10% Initial value 70 mph 3% 25 mph

Top 5 sensitive parameters

$110 / SFT 45 mph

Sensitivity Analysis

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SLIDE 22

Parameter Study

Parameter Matrix

Short-span bridge (30ft - 60ft) Double span (45ft) Medium-span bridge (60ft - 110ft) Double span (60ft) Long-span bridge (110ft - ) Double span (122ft) Low traffic below Bridge Low traffic above bridge

C C N/C

High traffic above bridge

C C N/C

Medium traffic below bridge Low traffic above bridge

C C C

High traffic above bridge

N/C C C

High traffic Below bridge Low traffic above bridge

N/C C C

High traffic above bridge

N/C C C

C: Considered N/C : Not considered (Not so common)

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SLIDE 23

High-traffic-below & High-traffic-above

1.22 1.23 2.17 8.33 7.99 3.79

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 Black Steel Epoxy-Coated Steel CFRP

Initial Cost Life-cycle Cost

Initial cost ratio 1 : 1.01 : 1.78 LCC ratio 1: 0.96 : 0.45

Long span Box Beam Bridge (122 ft span)

6.98 6.80 3.57

Black Steel Epoxy-Coated Steel CFRP

High-traffic-below & Low-traffic-above

Initial cost ratio 1 : 1.01 : 1.78 LCC ratio 1: 0.97 : 0.51

1.22 1.23 2.17 5.84 5.66 3.31

Black Steel Epoxy-Coated Steel CFRP

Medium-traffic-below & Low-traffic-above

Initial cost ratio 1 : 1.01 : 1.78 LCC ratio 1: 0.97 : 0.57

1.22 1.23 2.17

Medium-traffic-below & High-traffic-above

7.19 6.85 3.54

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 Black Steel Epoxy-Coated Steel CFRP

Initial cost ratio 1 : 1.01 : 1.78 LCC ratio 1: 0.95 : 0.49

1.22 1.23 2.17

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SLIDE 24

Initial Cost Life-cycle Cost

High-traffic-below & High-traffic-above

0.59 0.61 0.98 5.98 5.63 2.23

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 Black Steel Epoxy-Coated Steel CFRP

Initial cost ratio 1 : 1.03 : 1.66 LCC ratio 1: 0.94 : 0.37

Medium span Box Beam Bridge (60 ft span)

4.78 4.60 2.01

Black Steel Epoxy-Coated Steel CFRP

High-traffic-below & Low-traffic-above

Initial cost ratio 1 : 1.03 : 1.66 LCC ratio 1: 0.96 : 0.42

0.59 0.61 0.98

Medium-traffic-below &High-traffic-above

4.72 4.38 1.91

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 Black Steel Epoxy-Coated Steel CFRP

Initial cost ratio 1 : 1.03 : 1.66 LCC ratio 1: 0.93 : 0.40

0.59 0.61 0.98 3.52 3.34 1.69

Black Steel Epoxy-Coated Steel CFRP

Medium-traffic-below & Low-traffic-above

Initial cost ratio 1 : 1.03 : 1.66 LCC ratio 1: 0.98 : 0.48

0.59 0.61 0.98

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SLIDE 25

Initial Cost Life-cycle Cost

Initial cost ratio 1 : 1.02 : 1.53 LCC ratio 1: 0.88 : 0.41

Short span Box Beam Bridge (45 ft span)

Medium-traffic-below & Low-traffic-above

0.69 2.31 2.12 1.11

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 Black Steel Epoxy-Coated Steel CFRP

Initial cost ratio 1 : 1.02 : 1.53 LCC ratio 1: 0.92 : 0.48

0.45 0.46

Low-traffic-below & High-traffic-above

2.82 2.47 1.16

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 Black Steel Epoxy-Coated Steel CFRP

0.69 0.45 0.46 1.66 1.47 0.93

Black Steel Epoxy-Coated Steel CFRP

Low-traffic-below & Low-traffic-above

Initial cost ratio 1 : 1.02 : 1.53 LCC ratio 1: 0.89 : 0.56

0.69 0.45 0.46

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SLIDE 26

Initial Cost Comparison

1.23 0.61 0.46 2.17 0.98 0.69 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 Long-span Medium-span Short-span

Epoxy-coated CFRP

LCC Comparison (Most traffic)

7.99 5.63 2.47 3.79 2.23 1.16 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 Long-span Medium-span Short-span

LCC Comparison (Least traffic)

5.66 2.04 1.47 3.31 1.33 0.93 Long-span Medium-span Short-span

1: 1.76 1: 1.61 1: 1.50 1: 0.47 1: 0.40 1: 0.47 1: 0.58 1: 0.65 1: 0.63

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SLIDE 27

Conclusions

  • Bridges built with CFRP reinforcement are mo

more re econom

  • nomical than traditional bridges for LLC
  • Medium-span bridge is the most cost-efficient on

initial construction cost when CFRP reinforcement is used

  • Among these thirteen bridges, “Medium-span with High-

traffic-below & High-traffic-above” is the most cost- efficient one when CFRP reinforcement is integrated in the design

With the results of the completed analysis of all the thirteen side- by-side box beam bridges, the following conclusions have been drawn:

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SLIDE 28

THANK YOU!