aashtoware brm 5.2 - etouches · brm help desk . aashtowarebridge.com [email protected] . jira...

AASHTOWare BrM 5.2.3 Deterioration and LCCA

April 26, 2017 Mesa, Arizona

BrM Help Desk AASHTOWareBridge.com

[email protected] JIRA tickets: bridgeware.atlassian.net

Josh Johnson, PE TAM Lead Engineer [email protected]

• Contact • Element

Deterioration • NBI/Component

Deterioration • NBI Conversion • LCCA

Presenter

Presentation Notes

Before we start, let’s make sure you have our contact info.

http://aashtowarebridge.com/?page_id=14

Element Deterioration

CS 1

CS 2

CS 3

CS 4

T12

T23

T34

Markov

• Estimates the annual transition of elements between four discrete condition states: • CS1 – Good • CS2 – Fair • CS3 – Poor • CS4 – Severe

• Given that 100% of the element

is in Condition State 1 today, in how many years will only half of that element remain in the Condition State 1?




Presenter

Presentation Notes

Previously, this process of deterioration was predicted through a Markov model, which required a parameter to dictate how quickly the deterioration proceeded between each CS. The parameters were Median Years to Transition (T), or the number of years it would take 50% of the element currently in a CS to proceed to the next one.

Deterioration modeling is applied individually for each bridge element





Overall health of the bridge is evaluated by the bridge health index:

𝐻𝐻. 𝐼𝐼. = ∑ 𝑞𝑞𝑒𝑒𝑤𝑤𝑒𝑒𝐻𝐻𝐼𝐼𝑒𝑒𝑒𝑒∑ 𝑞𝑞𝑒𝑒𝑤𝑤𝑒𝑒𝑒𝑒

, where 𝐻𝐻𝐼𝐼𝑒𝑒 - element’s health index = 𝐶𝐶𝑆𝑆1 + 2

3 𝐶𝐶𝑆𝑆𝐶 + 1

3 𝐶𝐶𝑆𝑆𝐶

𝑞𝑞𝑒𝑒 - element’s total quantity 𝑤𝑤𝑒𝑒 - relative weight





Deterioration models are a combination of: • Weibull Survival Function • Markovian Process

The Weibull Function models only CS1 to CS2 transition (i.e. the onset of deterioration). The Markovian Process models the rest of transitions (CS2 to CS3 and CS3 to CS4).





Presenter

Presentation Notes

A pure Markov model begins deterioration at a steady rate from day 1, which is unrealistic for most elements. The current state of deterioration modeling uses a Weibull model for deterioration between CS1 and CS2, and a Markov model for the rest of the deterioration. A Beta value of 1.0 matches a Markov model, while larger numbers delay the onset of deterioration.

ß

Weibull CS 1

CS 2

CS 3

CS 4

T12

T23

T34

Markov

Element Deterioration • Contact • Element






Presenter

Presentation Notes

This graph compares the deterioration out of CS1 of an arbitrary element with a Markov model and a Weibull model. Note that deterioration of the Weibull has a comparatively delayed onset.

• Affects only CS1 to CS2 transition. • A shaping parameter (β) controls the shape of the

curve. • β = 1 is equivalent to Markov model • Slower deterioration rates in the early stage (based

on β values)




Presenter

Presentation Notes

This graph shows the effects of the Beta parameter on the shape of the Weibull curve. The blue line is a Beta value of 1.0, which is identical to a Markov model. The other lines show a Beta value of 2.0, 3.0, and 4.0.

Markovian model only (T1: 29, T2: 13, T3: 9, β: 1) Weibull + Markovian model (T1: 29, T2: 13, T3: 9, β: 1.8) Increasing T2 by 50% (T1: 29, T2: 20, T3: 9, β: 1.8) Increasing both T2 and T3 by 50% (T1: 29, T2: 20, T3: 14, β: 1.8)




• Protective Systems • Designed to slow element deterioration. • An element may contain several protective

systems




330 – Metal Bridge Rail 515 – Steel Protective Coating




ppe+: 1.0 (no protection)

ppe+: 1.5

ppe+ 2.0

ppe+: 2.5

Environmental Factors • Specified as modifiers that multiply the

default transition times of elements. • Environment factors:

• Benign: 2 • Low: 1.5 • Moderate: 1 • Severe: 0.7







Ben(1): 2.0 Low(2): 1.5 Mod(3): 1.0 Sev(4): 0.7

Estimates the future ratings of NBI components: • Deck • Superstructure • Substructure • Culvert

Implementation approaches: • Converting forecasted element ratings to NBI

ratings • Make use of element level deterioration • Using dedicated NBI deterioration models • Assign a number of years for a bridge to spend

in each NBI rating

NBI/Component Deterioration • Contact • Element



Presenter

Presentation Notes

One method of estimating how NBI ratings will deteriorate over time is to use element level deterioration and convert the predicted element level data into NBI Component level data. This is done through the NBI Converter, in which the user can limit the maximum amount of its constituent elements in each condition state. If the user does not wish to use element level deterioration, they can simply assign a number of years for the bridge to spend in each NBI rating before transitioning to the next NBI rating. This results in a very predictable deterioration pattern.

NBI Years 9 1 8 3 7 6 6 8 5 8 4 10 3 2 1

NBI Direct Deterioration




Presenter

Presentation Notes

If the user does not wish to use element level deterioration, they can simply assign a number of years for the bridge to spend in each NBI rating before transitioning to the next NBI rating. This results in a very predictable deterioration pattern.




Presenter

Presentation Notes

This image is not from the software but is for illustrative purposes only

NBI Conversion

Maximum Allowed NBI CS 1 % CS 2 % CS 3 % CS 4 % 9 100 0 0 0 8 100 5 5 1 7 100 20 5 2 6 100 100 10 3 5 100 100 20 5 4 100 100 100 15 3 100 100 100 100 2 100 100 100 100 1 100 100 100 100




Presenter

Presentation Notes

This table shows how a user would input their preferences for the cutoffs between each NBI rating. After the distribution of condition states in the elements that make up the component are calculated, each NBI rating is evaluated. In this case, if the component has more than 0% in CS2, CS3, or CS4, it does not meet the criteria and is evaluated for NBI 8, where it is allowed as much as 5% in CS2, 5% in CS3, and 1% in CS4. This process continues until the component satisfies the criteria for an NBI rating.

NBI Conversion Group by Unit




Presenter

Presentation Notes

Element CS distributions can not be directly averaged together for a component CS distribution because this would not reflect differences in amount and importance of different elements. The first method of combining the condition state distributions of elements into a single component condition state score is to average the elements CS ratings with other elements with the same units, and then to average the resulting CS distributions together before weighing the result against the translator. This allows element quantity to be used for a weighted average against other elements with the same units without letting inherently less frequent elements, like those measured by ‘each’, to be overshadowed by elements measured in ft.

NBI Conversion Relative Weight




Presenter

Presentation Notes

The second method is a direct weighted average. Elements are weighted by their quantity and by their element weight, which the user also assigns. Elements measured in “Each” would be assumed to be weighted much more heavily to offset their naturally lower quantity.

NBI Conversion Calibration




Presenter

Presentation Notes

In order to decide on the best parameters for the NBI Conversion, BrM supplies a calibration tool. The tool shows a table of how many structures were in each NBI rating at their last inspection as assigned by the inspectors, how many structures would be in each NBI rating if they were deteriorated at the element level between the last inspection and today and then converted, and how many structures would be converted to each NBI rating after 5 and 10 years of predicted element level deterioration. All of this is done assuming no action is taken to repair or preserve the structures. The table can be restricted to show only certain bridges, and only certain components or the NBI rating for the entire structure, which is determined by the lowest NBI rating of any component. This tool helps the user fine tune their conversion parameters to produce realistic results.

Life Cycle Cost Analysis (LCCA) • Short-Term analysis: 5 years

• Considers project alternatives in a short-term program

• Example: • Bridge Rehab, Deck Rehab, etc.

• Long-Term analysis: 75

• Considers what happens to the bridge after the program.

• Applies preservation policies




Preservation Policies Life Cycle Cost Analysis (LCCA) • Contact

• Element Deterioration

• NBI/Component Deterioration

• NBI Conversion • LCCA

Component Conditions Action Deck Deck NBI = 6 Epoxy Overlay (Thin Bonded Polymer)

Deck Deck NBI = 5 Concrete Deck Overlay (Polyester Concrete Overlay)

Deck Deck NBI <=4 and Super NBI >= 5 and Sub NBI >= 5 Deck replacement

Super (515) - Steel Protective Coating < 40 and (107) Steel Opn Girder/Beam > 60

Paint

Super (107) Steel Opn Girder/Beam < 50 Repair Beams Sub Substructure HI < 50 Substructure Rehab Bridge Super NBI <= 4 or Sub NBI <= 4 Bridge Replacement

Utility

𝐿𝐿𝐶𝐶𝐶𝐶𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈 = 1 −𝐿𝐿𝐶𝐶𝐶𝐶

𝐶 × 𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟 𝑟𝑟𝑐𝑐𝑐𝑐𝑟𝑟× 100

𝐿𝐿𝐶𝐶𝐶𝐶 = ST + LT − 𝑅𝑅𝑟𝑟𝑐𝑐𝑅𝑅𝑅𝑅𝑅𝑅𝑟𝑟𝑟𝑟

𝑅𝑅𝑟𝑟𝑐𝑐𝑅𝑅𝑅𝑅𝑅𝑅𝑟𝑟𝑟𝑟 =𝑅𝑅𝑟𝑟𝑟𝑟𝑟𝑟𝑅𝑅𝑟𝑟𝑅𝑅𝑟𝑟𝑅𝑅 𝑆𝑆𝑟𝑟𝑟𝑟𝑆𝑆𝑅𝑅𝑟𝑟𝑟𝑟 𝐿𝐿𝑅𝑅𝐿𝐿𝑟𝑟

𝑆𝑆𝑟𝑟𝑟𝑟𝑆𝑆𝑅𝑅𝑟𝑟𝑟𝑟 𝐿𝐿𝑅𝑅𝐿𝐿𝑟𝑟× 𝑅𝑅𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟 𝐶𝐶𝑐𝑐𝑐𝑐𝑟𝑟

Life Cycle Cost Analysis (LCCA) • Contact • Element



Life Cycle Cost Analysis (LCCA) Updated Utility – Rehab Project

𝐿𝐿𝐶𝐶𝐶𝐶 = 𝑆𝑆𝑇𝑇 + 𝐿𝐿𝑇𝑇 − 𝑅𝑅 = $260,570 + $345,032 − $53,911 = $551,691

𝐿𝐿𝐶𝐶𝐶𝐶𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈𝑈 = 1 −$551,691

𝐶 × $1,6𝐶5,000× 100 = 𝟖𝟖𝟖𝟖.𝟎𝟎𝟎𝟎

𝐵𝐵𝑟𝑟𝑟𝑟𝑟𝑟𝐿𝐿𝑅𝑅𝑟𝑟 = 83.02 − 75.83 = 𝟕𝟕.𝟏𝟏𝟗𝟗




BrM Help Desk AASHTOWareBridge.com

[email protected] JIRA tickets: bridgeware.atlassian.net

Josh Johnson, PE TAM Lead Engineer [email protected]

Presenter

Presentation Notes

For further help, feel free to reach out to us.

http://aashtowarebridge.com/?page_id=14

aashtoware brm 5.2 - etouches · brm help desk . aashtowarebridge.com [email protected] . jira...

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