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Cost-Benefits Analysis in SHM ProjectsOpening Keynote at SHMII-5Daniele Inaudi

Is SHM about Monitoring Bridges?

Is SHM about Insuring Safety of Dams?

Is SHM about reducing Risk in Excavations?

Is SHM about Avoiding Leakages in Pipelines?

Is SHM about Adding Prestige to a Building?

Is SHM about Preserving Natural

Resources?

Is SHM about Enabling Remote Management?

SHM is about all of this and more…

SHM has evolved from being a research

topic…

…to being an Industry

An « Industry » is a meeting place

between Supply and Demand…

… between Cost and Perceived Benefits

This presentation is about defining Cost and Benefits from a Customer-Supplier

Relationship Perspective

WARNING:This presentation has

no sophisticated financial models or a universal recipe for

commercial success…

… just some personal observations derived

from practice

Defining CostCapital Investment

+Operational Costs

Cost: Capital Investment

SHM design costs, including:Integration with the structure’s designPlanning and project management

Cost: Capital Investment

Hardware costs:SensorsCablesData acquisition and management hardwareCommunication

Cost: Capital Investment

Installation costs:Integration with building scheduleConfiguration CommissioningReporting

Operational Costs

System maintenanceSpare parts and consumablesEnergyCommunication

Operational Costs

Data ManagementPublishingArchiving

Operational Costs

Data analysisInterpretation Reporting

Load

A8

A7

A6

A5

A4

A3

A2

A1 B1

N Force [KN] Friction [KN/m2]

Laye

r1Zo

ne II

Zone

III

Layer 9

Zone

I

-4652

-2503

-3405

-1925

-1562

-777

-104

-4307

-9321

-8588

-6905

-5222

-3184

-3418

-2115

-1053

L=480t L=840t L=480t L=840t

108.

8910

5.54

127.

73

81.7

366

.57

94.9

3

-14.

61

22.7

3

58.3

556

.56

36.2

649

.25

42.2

244

.67

34.00

Depth[m]

8.45

12.62

16.85

21.08

25.30

29.54

2.30

6.40

10.50

14.73

18.96

23.19

27.42

31.65

4.35

Total Costs

Typically 0.5 – 3% of new construction costsHardware cost typically less than 50% of total costTotal Investment+ recurring costs are important for the owner

Identifying Benefits

Hard Benefitsvs.

Soft Benefits

Capital ValueHard(ly) Benefit

Reduction of Risk(hard and soft benefit)

Crack Detection in Tunnel

Approx. cost: 800’000€Benefits: Risk Reduction:

insurance

Increase Safety(hard and soft benefit)

Sinkhole detection and localization

Approx. cost: 400’000$Benefits: Risk Reduction: insurance, safety of rail

Increase Quality(hard and soft benefit)

Building Monitoring

Approx. cost: 25’000$ /buildingBenefits: Quality control, image

Average strain evolution May 2001 - June 2007

-800

-700

-600

-500

-400

-300

-200

-100

024

/05/

01

22/1

1/01

24/0

5/02

23/1

1/02

24/0

5/03

23/1

1/03

24/0

5/04

23/1

1/04

24/0

5/05

23/1

1/05

25/0

5/06

24/1

1/06

25/0

5/07

Date

Aver

age

stra

in [

me]

C1 (1675) C2 (1668)

C3 (1676) C4 (1669)

C5 (1663) C6 (1683)

C7 (1670) C8 (1682)

C9 (1662) C10 (1677)

Discover Structural Reserves

(hard benefit)

Loads on Arena roof

Approx. cost: 250’000$Benefits: Avoid strengthening

RS-232

C.M.P.

PC with Software

Ethernet

Worst-case scenario

Strain limit: 900µε

Early detection of defects

(hard benefit)

Bridge enlargement

Approx. cost: 150’000€Benefits: verify design, no

defects

Strain limit: 900µε

Safe Lifetime Extension

(hard benefit)

SHM before ReplacementBridge Candidate for Replacement:• Cost of Replacement, no SHM: 100%• Cost of SHM: 3%• Bridges found to be OK: 20%• Bridges needing rehabilitation: 20%• Cost of rehabilitation: 30%• Bridges needing replacement: 60%• Cost with SHM: 3%+20%x30%

+60%=69%• Saving from SHM: 31% !!!

Fatigue Crack Detection

Approx. cost: 1’000’000€Benefits: Postpone replacement

15 years

Increase Knowledge(soft benefit)

Full-scale testing of shaft

Approx. cost: 200’000$Benefits: Grants, pubblications

Adhere to standards and regulations(soft benefit)

Nuclear Power Plant

Approx. cost: 2’000’000€Benefits: Comply to

regulations, demonstrate safety

Image, prestige and public perception

(soft benefit)

New I35W Bridge

Approx. cost: 500’000$Benefits: Reassure public, help

fast construction, long-term SHM, data for research

Designing SHM Systems to Maximize

Owner’s Benefits

7 STEPS SHM Methodology1. Identify structures needing monitoring2. Acquire information on probable risks

and opportunities from design engineers or owners

3. Establish expected responses4. Design SHM system to detect such

responses and select appropriate sensors

5. Install and calibrate system6. Acquire and manage data7. Asses field data

1: Indentify Structures• New structures including innovative aspects.• New structures with unusual associated risks or

uncertainties, including geological conditions, seismic risk, meteorological risk, aggressive environment, vulnerability during construction, quality of materials and workmanship.

• Structures that are critical at a network level. • New or existing structure which is representative

of a larger population of identical or very similar structures.

• Existing structures with known deficiencies or very low rating.

• Candidates for replacement or major refurbishment works.

2: Risk/Opportunity Analysis• The SHM system designer, the design

engineers or the engineers in charge of the structural assessment and the owner, must jointly identify the risks and opportunities associated with the specific structure and their probability

• The analysis will lead to a list of possible events and degradations that can possibly affect the structure, their impact an probability

• The result of this step is a list of risks and opportunities that must be addressed by the SHM system

3: Responses

• For each risk and opportunity, associate one or several responses that can be observed directly or indirectly

• Roughly quantify the expected responses

• Define locations• Define risks to be addressed by

inspection and by SHM

4: Design SHM System• Select appropriate sensors and

technologies• Consider the required lifetime of the

SHM system• Consider the available budget• Consider reliability and redundancy• Consider installation and schedule

5: Installation and Calibration• Installation and testing of all

components• Verify correct installation in

accordance to the specifications• Site Acceptance Test (SAT)

6: Data Acquisition/ Mng • Database system• Data preservation• Data distribution and access• Documentation of interventions and structural

lifetime

7: Data Assessment

• By analyzing the responses of the structure, the engineer will be able to identify if any of the foreseen risks and degradations have materialized and if any of the opportunities are confirmed

• Establish procedures to respond to the detection of any degradation

• The analysis of the data might prompt for further investigation, including inspection, testing or installation of additional sensors

• Alerts, Warinings and periodic reports.

Retaining Forces

What is limiting SHM?

• Difficulty to estimate costs and benefits

• Too many actors• No resources to

manage SHM projects

• Need Actionable information, not data

• Limited budget

Competitor #1Doing Nothing

Competitor #2Fixing Potholes

Competitor #3Keep doing what you

always did

So…Where is the universal recipe for commercial

success in SHM?

As with any other business,

understanding and satisfying end-user

needs and identifying benefits is crucial

The good SHM designer has two ears, but only one

mouth

The bait must be appealing to the fish, not to the fisherman

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Cost-Benefits Analysis in SHM ProjectsDaniele Inaudi