life cycle cost analysis for short and medium span bridges

LIFE CYCLE COST ANALYSIS FOR SHORT AND MEDIUM SPAN BRIDGESJTRP RESEARCH STUDY SPR-3914

SPR RESEARCH COMMITTEE:

TIMOTHY WELLS (CHAIR)

JEREMY HUNTER

RON McCASLIN

EDWARD SPAHR

ROAD SCHOOL 2018

1

OUTLINE

2

• INTRODUCTION AND MOTIVATION

• OBJECTIVES

• BRIDGE LIFE CYCLE COST ANALYSIS (BLCCA)

– Design program

– Deterioration factors

– Cost allocation

– Blcca implementation

• CONCLUDING REMARKS AND FUTURE WORK

INTRODUCTION AND MOTIVATION

3

• Life cycle cost analysis (LCCA):

Method used to assess the total cost of aproject. LCC is particularly useful when a singleproject has different alternatives that fulfillthe original requirements


4

• Bridge life cycle cost analysis (BLCCA): Initial costs:

Number of substructure elements

Deck span

Thickness for the superstructure

Span length

Material properties

Contractors experience


5

• Bridge life cycle cost analysis (BLCCA):Long term costs:

Repair or rehab of the bridge deck

Repair of collision-damaged girders

Re-painting steel bridge

Replace of the deck

Routine maintenance

Miscellaneous minor repairs such as spot painting or concrete patching

Mostly focused in scheduling and modeling.

Potential impact in decision makers.

Frangopol and Soliman (2016) BLCCA and other LCCAresearch efforts are not often use in practice.


6

• BLCCA in the literature:

OBJECTIVES

7

The main goal of this study is to identify themost cost effective bridge design solutions fordifferent span ranges and span configurationsbased on the Life Cycle Cost Analysis instead ofthe first cost approach currently used.

TASKS

8

1. Evaluate different design solutions for different spanarrangements in terms of its cost-effectiveness using BridgeLife Cycle Cost Analysis.

2. Identify the most effective bridge solutions in differentspan ranges.

3. Propose maintenance and work actions schedule fordifferent superstructure types.

4. Identify the most cost-effective major work actions foreach design option from the LCCA stand point.

OUTLINE BLCCA

9

• Alternatives

• Bridge Types

• Span Ranges

• Span Configuration

• Design

1. Design Program

• Condition Rating

• Deterioration Rates

2. Deterioration Factors • Agency Costs

• User Costs

3. Cost Allocation

• LCC Profiles

• LCCA

• Deterministic

• Stochastic

4. LIFE CYCLE COST

1. DESIGN PROGRAM

10

1.1 Bridge alternatives:Summary Material Types INDIANA

Material ID % Quantity

1,2 Concrete 29.11% 5573

3,4 Steel 27.01% 5172

5,6 Prestressed 38.28% 7328

7, up Other 5.60% 1072

TOTAL 19145 Concrete29%

Steel27%

Prestressed38%

Other6%

STRUCTURAL TYPES (NBI DATABASE)

1. DESIGN PROGRAM

11

1.1 Bridge alternatives:

Prestressed Concrete Box

Beams4% Structural Steel

Beams17%

Prestressed Concrete Bulb-

Tee Beam27%

Prestressed Concrete AASHTO

Beams18%

Structural Steel Girder

Reinforced Concrete Slab

11%

Prestressed Concrete Hybrid Bulb-Tee Beam

12%

STRUCTURAL TYPES

TOTAL BRIDGES IN THE DATA BASE: 389

GOES FROM 2011 to 2015

Summary Types

Type ID % Quantity

Prestressed Concrete Box Beams 1 3.87% 15

Structural Steel Beams 2 17.27% 67

Prestressed Concrete Bulb-Tee Beam 5 27.58% 107

Prestressed Concrete AASHTO Beams 4 17.78% 69

Structural Steel Girder 3 11.08% 43

Reinforced Concrete Slab 6 10.82% 42

Prestressed Hybrid Bulb-Tee Beam 7 11.60% 45

Reinforced Concrete Beam 8 0.26% 1

1. DESIGN PROGRAM

12

1.1 Bridge alternatives:

Concrete Options

Slab bridges

Prestressed concrete box beams

Prestressed concrete AASHTO beams

Prestressed concrete Bulb tees and hybrid bulb tees

Steel Options

Structural steel beams

Steel plate girders

Structural steel folded plate beams

SDCL beams

1. DESIGN PROGRAM

13

1.1 Bridge alternatives:Steel folded plate beams

Standard shapes built from bending flat steel plates using a break press.

According to the Short Span Steel Bridge Alliance (SSSBA) a maximum span of 60ft.

Narendra Taly and Gangarao (1979)

Barth et al (2015)

Civjan et al (2016)

Pavlich et al (2008)

1. DESIGN PROGRAM

14

1.1 Bridge alternatives:SDCL

Simple spans steel members at the early construction stages (Dead Load)

Concrete diaphragm during construction create a continuous structural system (Live Load)

Azizinamini (2005)

Hoorpah at al (2015)

Zanon et al (2015)

Indiana Experience:

2011 Project SR 246

80ft max span. 6 Spans

OUTLINE BLCCA

15

• Alternatives

• Bridge Types

• Span Ranges


• Design

1. Design Program




• User Costs

3. Cost Allocation

• LCC Profiles

• LCCA

• Deterministic

• Stochastic

4. LIFE CYCLE COST

1. DESIGN PROGRAM

16

1.2 Span Ranges:Summary Ranges

Ranges IDSpan

% QuantityMinimum Maximum

0 Culverts LESS THAN 20 FT 5.8% 1113

1 Range 1 30 60 41.6% 7960

2 Range 2 60 90 17.3% 3315

3 Range 3 90 130 6.1% 1164

4 Range 4 130 200 2.2% 430

N/A N/A 20 30 27.0% 5163

100.00% 19145

TOTAL BRIDGES INVENTORY: 19,145 (NBI DATA 2016)97% (18,073) of Total INDIANA Inventory are concrete and steel

65% of Total INDIANA Inventory

OUTLINE BLCCA

17

• Alternatives

• Bridge Types

• Span Ranges


• Design

1. Design Program




• User Costs

3. Cost Allocation

• LCC Profiles

• LCCA

• Deterministic

• Stochastic

4. LIFE CYCLE COST

1. DESIGN PROGRAM

18

1.3 Span Configuration

Summary Spans

SPANS ID % Quantity

1 1 SPAN 49.6% 9487

2 2 SPANS 10.1% 1941

3 3 SPANS 32.1% 6139

4 4 SPANS 4.3% 818

5 MORE THAN 5 SPANS 4.0% 760

TOTAL 19145

1 SPAN50%

2 SPANS10%

3 SPANS32%

4 SPANS4%

MORE THAN 5 SPANS

4%

Span Ranges

1. DESIGN PROGRAM

19

1.3 Span Configuration

0.45~0.50

0.35

0.50 0.50

0.32 0.36 0.32

SPAN RANGE 1 and 2

SPAN RANGE 3

OUTLINE BLCCA

20

• Alternatives

• Bridge Types

• Span Ranges


• Design

1. Design Program




• User Costs

3. Cost Allocation

• LCC Profiles

• LCCA

• Deterministic

• Stochastic

4. LIFE CYCLE COST

1. DESIGN PROGRAM

21

1.4 Design Standard Values:

• Width: 43'

• Lanes: 2 (12' wide with 8' wide shoulders)

• Railings: New Jersey according to drawing E706-BRSF INDOT

• Skew: 0° (average skew=20°)

• Moderate AADT

• Concrete deck of 8 in, min long reinf. 5/8”

• Max rebar spac 8 in.

1. DESIGN PROGRAM

22


• Structural steel ASTM A709 Gr 50. E: 29,000ksi, Fy: 50ksi Fu: 65ksi

• Reinf steel AASHTO A615 Gr 60. E: 29,000ksi, Fy: 60ksi Fu: 80ksi

• PS Strands: Low relax strands. E: 28,500ksi, Fy: 243ksi Fu: 270ksi

• Slab concrete f’c: 4ksi, E: 3,834ksi

• Concrete PS beams f’c: 7ksi. E: 5,072ksi. Conditions at transfer may vary.

1. DESIGN PROGRAM

23


1. DESIGN PROGRAM

24

FINAL DESIGN PLAN SIMPLY SUPPORTED BRIDGES

SR 1 SR 1 SR 1 - 2 SR 2 SR 2-3 SR 3

30 45 60 75 90 130

X X

X X X X X X

X X X X X

X X X X X X

X X X

X X X

X X X X

X X

Span Range (SP)

PS Concrete Beam

Folded Steel Plate

PS Concrete Box

PSC Bulb Tee

Steel Girders

SUPERSTRUCTURE

TYPE

Span

Slab Bridge

Steel beam (5B)

Steel beam (4B)

1. DESIGN PROGRAM

25

FINAL DESIGN PLAN CONTINUOUS BRIDGES

SR 1 SR 1 SR 1 SR 1 - 2 SR 2 SR 2-3 SR 3

30 45 50 60 75 90 130

X X X

X X

X X

X X X X

X X X

X X X

X X X X

X X X X

X X X X

X X X X

SDCL Beams (5B)

SDCL Beams (4B)

2 Span Configuration

Span Range (SP)

Slab Bridge

Steel beam (5B)

Steel beam (4B)

SUPERSTRUCTURE TYPE

PS Concrete Beam

Folded Steel Plate

PS Concrete Box

PSC Bulb Tee

Maximum Span

Steel Girders

OUTLINE BLCCA

26

• Alternatives

• Bridge Types

• Span Ranges


• Design

1. Design Program




• User Costs

3. Cost Allocation

• LCC Profiles

• LCCA

• Deterministic

• Stochastic

4. LIFE CYCLE COST

2. DETERIORATION CURVES

27

2.1 Condition Ratings:

National Bridge Inventory (data since 1992)

STATE DESCRIPTION

N Not Applicable

9 Excellent Condition

8 Very Good Condition - No problems noted

7 Good Condition - Some minor problems

6 Satisfactory Condition

5 Fair Condition

4 Poor Condition

3 Serious Condition

2 Critical Condition

1 "Imminent" Failure Condition

0 Failed Condition

a) Deterministic models

b) Stochastic Models

Definition:

Predicting the future condition of infrastructure assets.


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• 2.1.1 Deterministic Analysis:

• The output obtained is commonly expressed by deterministic values that represent the average predicted condition.

– Extrapolations

– Regressions or

– Curve-fitting techniques.

𝑦 =

123…𝑛

𝑦 = 𝐶1𝑥𝑛 + 𝐶2𝑥

𝑛−1 +⋯+ 𝐶𝑛−2𝑥2 +

𝐶𝑛−1𝑥 + 𝐶𝑛

Nebraska DOT, Morcous (2007, 2011 and 2015)Some research using Indiana assets


29


Nebraska DOT, Morcous (2011)Some research using Indiana assets

• 2.1.2 Stochastic Analysis:

• Deterioration progression is set as one or more stochastic variables that capture the uncertainty of the process

– Markov Chains

» Time based

» State based.

𝑦 =

123…𝑛

𝑇𝑃𝑀 =1 ⋯ 𝑝(𝑥)𝑛1⋮ ⋱ ⋮

𝑝(𝑥)1𝑛 ⋯ 1

𝐶𝑅 = 𝐶𝑅0𝑇𝑃𝑀𝐴𝑔𝑒


30

2.2 Deterioration Rates:

• Two sources:

1. M. Moomen, Y. Qiao, B. R. Agbelie, S. Labi, and K. C. Sinha, Bridge Deterioration Models to Support Indiana’s Bridge Management System. 2016.• Deterministic approach based on curve fitting techniques and NBI

condition rating database (SPR 3828) (Concrete options)

2. Kepaptsoglou, K., and Sinha, K.C., 2002. IBMS Technical Manual 2002• Continuous regression models (SPR 3013) (Steel options)


31


SL= 80 YearsSL= 38 Years


32


SL= 65 Years

SL= 60 Years

OUTLINE BLCCA

33

• Alternatives

• Bridge Types

• Span Ranges


• Design

1. Design Program




• User Costs

3. Cost Allocation

• LCC Profiles

• LCCA

• Deterministic

• Stochastic

4. LIFE CYCLE COST

3. COST ALLOCATION

34

• Variation of concrete price through different time periods (Average values).

– 2011 to 2016:

• All = $621/yd3

• Concrete = $591/yd3

• Steel = $698/yd3

– 2016 only:

• All = $802/yd3

• Concrete = $829/yd3

• Steel = $786/yd3 VARIABLE CONCRETE UNIT PRICE DEPENDING ON THE STRUCTURE TYPE IS NOT A FACTOR.

3.1 Agency costs:

3. COST ALLOCATION

35

3.1 Agency costs:

Maximum Minimum Average

Concrete C Superstructure yd3 1,662.96$ 346.96$ 621.52$ 579.27$ 389.00

Concrete C Concrete All Configurations yd3 1,662.96$ 346.96$ 591.08$ 555.60$ 279.00

Concrete C Steel All Configurations yd3 1,465.63$ 410.44$ 698.70$ 632.36$ 110.00

Concrete C All Types Simply Supported yd3 995.55$ 415.74$ 581.71$ 564.87$ 108.00

Concrete C Concrete Simply Supported yd3 995.55$ 415.74$ 566.88$ 547.70$ 97.00

Concrete C Steel Simply Supported yd3 942.97$ 539.79$ 712.50$ 680.30$ 11.00

Concrete C All Types Continuous yd3 1,662.96$ 346.96$ 636.81$ 581.80$ 281.00

Concrete C Concrete Continuous yd3 1,662.96$ 346.96$ 603.98$ 557.43$ 182.00

Concrete C Steel Continuous yd3 1,465.63$ 410.44$ 697.17$ 629.14$ 99.00

Concrete C All Types 3 Spans yd3 1,662.96$ 346.96$ 646.78$ 600.59$ 143.00

Concrete C Concrete 3 Spans yd3 1,662.96$ 346.96$ 631.19$ 593.71$ 100.00

Concrete C Steel 3 Spans yd3 1,465.63$ 410.44$ 684.85$ 616.04$ 38.00

DataINDOT

ITEM UNIT Weighted

ҧ𝑥𝑤𝑒𝑖𝑔ℎ𝑡𝑒𝑑 =σ𝑖=1𝑛 𝑤𝑖𝑥𝑖σ𝑖=1𝑛 𝑤𝑖

ҧ𝑥 =1

𝑛

𝑖=1

𝑛

𝑥𝑖

3. COST ALLOCATION

36

3.1 Agency costs:

𝛼𝑆𝑙𝑎𝑏 =𝐶𝑜𝑛𝑐𝑟𝑒𝑡𝑒𝑆𝑙𝑎𝑏𝐶𝑜𝑛𝑐𝑟𝑒𝑡𝑒𝑇𝑜𝑡𝑎𝑙

=237𝑚3

270𝑚3= 88%

𝛼𝐷𝑖𝑎𝑝ℎ =𝐶𝑜𝑛𝑐𝑟𝑒𝑡𝑒𝐷𝑖𝑎𝑝ℎ

𝐶𝑜𝑛𝑐𝑟𝑒𝑡𝑒𝑇𝑜𝑡𝑎𝑙=

33𝑚3

270𝑚3= 12%

ҧ𝑥𝑤𝑒𝑖𝑔ℎ𝑡𝑒𝑑 =σ𝑖=1𝑛 𝑤𝑖𝑥𝑖σ𝑖=1𝑛 𝑤𝑖

𝑃𝑇𝑜𝑡𝑎𝑙 =σ𝑖=1𝑛 𝑤𝑖𝑥𝑖σ𝑖=1𝑛 𝑤𝑖

= 𝛼𝑆𝑙𝑎𝑏𝑃𝑆𝑙𝑎𝑏 + 𝛼𝐷𝑖𝑎𝑝ℎ𝑃𝐷𝑖𝑎𝑝ℎ = 88% Τ$529.27 𝑦𝑑3 + 12%𝑃𝐷𝑖𝑎𝑝ℎ = Τ$600.59 𝑦𝑑3

𝑃𝑆𝑙𝑎𝑏 = Τ$579.27 𝑦𝑑3

𝑃𝑇𝑜𝑡𝑎𝑙 = Τ$600.59 𝑦𝑑3 3 spans Configuration

• Percentage slab Concrete:– Price Slab= Simply Supported Price

• Percentage Diaphragm Concrete

𝑷𝑫𝒊𝒂𝒑𝒉 = Τ$𝟏𝟏𝟐𝟑. 𝟔𝟎 𝒚𝒅𝟑

• Prestressed concrete AASTHO continuous beams• Prestressed concrete Bulb tees• SDCL beam system• Closing pours for prefabricated options

3. COST ALLOCATION

37

3.1 Agency costs:

3. COST ALLOCATION

38

3.1 Agency costs:

OUTLINE BLCCA

39

• Alternatives

• Bridge Types

• Span Ranges


• Design

1. Design Program




• User Costs

3. Cost Allocation

• LCC Profiles

• LCCA

• Deterministic

• Stochastic

4. LIFE CYCLE COST

4. LCCA

40

4.1 LCC Profiles:

• Graphical representations of actions needed during the life span of the asset

– Life cycle length

» Material type

» Type of superstructure

– Working actions

» Maintenance

» Preventive

» ReplacementCleaning/washing

0 10 20 30 40 50 58

Bridge Construction

Bridge Reconstruction

Deck overlay

Sealing and Cleaning Sealing and Cleaning

4. LCCA

41

4.1 LCC Profiles:

Cleaning/washing

0 10 20 30 40 50 58

Bridge Construction

Bridge Reconstruction

Deck overlay

Sealing and Cleaning Sealing and Cleaning

Condition rating jumps due to rehabilitation, repair or replacement

Superstructure TypeNHS Bridges

(Unit)

# Bridges with

Jumps > 3 rat.% Reconstruction Action Repair Actions

Steel structures 1736 61 4% 22Superstructure

replacement39

Collision Damage repair

Localized section stregnthening

Superstreucture jacking elevation

Prestressed beams 748 13 2% 10Superstructure

replacement3

Partial Replacement

Beam ends Repair

Prestressed boxes320 10

3%10

Superstructure

replacement0

Slab bridges 1014 35 3% 27Superstructure

replacement8

Partial depth

External pos tensioning

Superstreucture jacking elevation

Total 3818 119 3% 69 50

4. LCCA

42

4.2 BLCC :

It is a helpful instrument to provide better information to decision-makers. General model BLCCA:

𝐿𝐶𝐶 = 𝐷𝐶 + 𝐶𝐶 +𝑀𝐶 + 𝑅𝐶 + 𝑈𝐶 + 𝑆𝑉

DC = Design Cost CC = Construction Cost

MC = Maintenance Cost RC = Rehabilitation Cost

UC = User Cost SV = Salvage Cost

4. LCCA

43

4.2 BLCC :

Different service life depending on the superstructure and material type.

P = Life Cycle Cost

i = Discount rate

SL = Service Life

𝑃𝑝 =𝑃

1 + 𝑖 𝑆𝐿 − 1

Present worth of life cycle in Perpetuity:

4. LCCA

44

4.2 BLCC :

4. LCCA

45

4.2 BLCC :

CONCLUDING REMARKS

46

• Deterioration rate and its usage in the estimation of service life has an important role into the LCCA.

• Cost allocation and work actions scheduling affect significantly the outcome of the LCCA.

• Consideration of long term cost changes the cost-effectiveness of the superstructure design alternative.

• Based on current data, concrete superstructures for simply supported structures are most cost-effective for span lengths greater than 75ft. However, steel options are more attractive for spans ranging from 50ft to 65ft.

FUTURE WORK

47

• Finalize design program and initial cost estimation

• Implement stochastic methodology into LCCA

– Identify probabilistic distributions for the different parametersused in BLCCA

• Make recommendations to designers of cost effectivesuperstructures depending on span range based on LCCA

48

THANK YOU! QUESTIONS?

life cycle cost analysis for short and medium span bridges

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