Pontis Applications and Models prepared by: Cambridge Systematics, Inc'

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Pontis Applications and Modelsprepared
byCambridge Systematics, Inc.
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Outline

• Overview of the Pontis Modeling Approach
• Special Topics in Modeling
• Triggering Actions with Smart Flags
• Definition of MRR versus Improvements
• Removing Structures from Consideration
• Pontis 4.0 Update

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Pontis Modeling Approach
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Modeling Approach Overview

• The Pontis BMS use an integrated set of models
  to recommend bridge preservation and improvements
• Preservation Model
• Optimization model used to recommend the policy
  to follow for maintaining bridge elements in a
  state of good repair
• A set of actions, or policy, is recommended for
  each element
• Program Simulation Model
• Simulation model used to recommend projects for
  each bridge over a specified period of time
• Objective is to maximize benefit given a budget
  constraint
• The preservation policy is an input to the
  simulation

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Decomposition of a Structure in Pontis
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How Pontis Sees BridgesElements Environments

• The concept of bridge elements is essential to
  Pontis
• Elements may be decks, beams, arches, joints,
  etc
• AASHTO has defined a set of commonly recognized
  (CoRe) elements. Agencies may define additional
  elements
• A particular element may exist in one of four
  environments
• Environments are generally used to describe
  different weather or operating conditions

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How Pontis Sees BridgesStates Actions

• Depending on the condition of an element, the
  element is assigned to one of up to five states
• Lowest state is the best condition, highest is
  the worst
• For each state, for a given element, there are up
  to three feasible maintenance actions that Pontis
  may recommend
• Actions are more general than would be required
  for complete project specification
• CoRe elements have pre-defined states and actions
  - agencies may define their own as well

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Pontis Preservation Policy

• Pontis recommends the optimal maintenance
  policy,or set of recommended actions for each
  state, foreach element-environment combination
• Preservation models are built basedon expert
  opinion (elicitations)and inspection history
• Each element ismodeled independently
• The preservation modelsoptimize based on
  discountedlong-term agency costs usinga
  Markovian decision model

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Predicting Element Conditions

• Pontis generates a transition probability (TP)
  matrix for each element-environment combination
• Specifies probability of transition to each state
  for each action, including do-nothing and
  do-something actions
• Rows of the matrix are actions, columns are
  states
• Built based on elicitations and inspection data
• One can predict future conditions by multiplying
  TP matrix by the vector representing current
  conditions
• Easiest to demonstrate this through a spreadsheet

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Pontis Program Simulation

• Predicts bridge maintenance and improvement
  needsover time
• Recommends projects for individual bridges given
  aprogram-level budget constraint
• Uses
• Preservation policy
• User-specified improvement policy and costs
• User benefit models
• Project scoping parameters

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Program Simulation Steps

• Compile bridge data
• Determine needs
• Preservation needs are generated by applying the
  preservation policy to each element on the bridge
• Improvement needs (widening, raising,
  strengthening) are generated based on the
  improvement policy
• Apply project scoping parameters
• Minimum project cost, etc. . .
• Many new parameters and rules in Pontis 4.0

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Program Simulation Steps (cont.)

• Generate the list of project alternatives
• Sort the list of project alternatives
• Select projects
• With an unlimited budget, Pontis will do the
  project with the most benefit for each bridge -
  often a replacement
• With a budget constraint, Pontis will pick
  projects to generate the most benefit with the
  available budget
• Calculate impact of projects and roll forward
  bridge conditions
• Repeat process for each year of the simulation

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Modeling Changes in Pontis 4.0

• No changes to the preservation model
• New alternatives for representing preservation
  benefits and sorting projects
• Many new project scoping parameters to generate
  more realistic projects
• Many new performance measures calculated by the
  simulation (e.g., sufficiency rating, HBRR
  eligibility)
• Better treatment of user-defined projects
• Many additional modeling and user interface
  improvements

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Special Modeling Topics
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Special Topics - Smart Flags

• By default, smart flags get ignored in the
  program simulation
• New functionality has been added in Pontis 4.0
  for specifying agency preservation policies
• Can specify that a certain smart flag condition
  should trigger action on another element
• Example When the Soffit Smart Flag is in State
  5, replace the deck if not in State 1
• To use this functionality it is necessary to
  define actions and transition probabilities for
  smart flags

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Special Topics - MRR versus Improvements

• Users can specify that the simulation should
  include
• MRR only
• Improvements only
• MRR and improvements
• MRR and improvement needs both may trigger
  replacement
• When improvements are excluded, Pontis will not
  evaluate the need for widening, raising or
  strengthening bridges
• It is not possible to redefine what is MRR and
  what is an improvement

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Special Topics - Excluding Structures

• It is possible to exclude selected structures
  from consideration in the program simulation
• In Pontis 4.0 structures with programmed work
  will generally be excluded by look ahead rules
  (dont work on the bridge if a replacement in
  planned)
• In Pontis 3.4/4.0 bridges can be excluded by
• Developing a structure list the excludes selected
  structures
• A field can be used or added to indicate whether
  to exclude the structure
• Run the program simulation for bridges meeting
  filter criteria only

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Pontis 4.0 Update
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Pontis 4.0 Update

• Pontis 4.0 is in final acceptance testing
• Release scheduled for Summer 2001
• User Meeting scheduled for September
• FY 2001-2002 activities
• Finalize user, technical manuals
• New training materials
• Pontis 4.1 planned - Bridgeware integration
  release

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Pontis 4.0 Inspection Enhancements

• Improved user interface
• Improved support for English units
• Support for inspector work candidates
• Inspectors recommend work for the bridge
• Can use Pontis actions, or other agency-defined
  actions
• Recommendations are presented in project planning
• Desktop enhancements

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Inspection Module Interface
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Network Decision Enhancements

• New simulation rules added to improve match of
  models to agency practice
• Improved treatment of user projects
• New performance measures projected as part of the
  program simulation
• NBI Ratings
• Sufficiency Rating
• SD/FO Status
• New Results Module

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Results Module Interface
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Project Planning Enhancements

• Completely new interface replacing previous
  project planning and action log module
• Powerful and intuitive tree view
• Tools to manage, combine, organize projects
• Incorporates user-defined projects, inspector
  candidate and Pontis candidate work

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Project Planning Interface
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Bridge Analysis Enhancements

• New functionality to
• See all work planned or recommended for a bridge
• Fine tune the work items
• See the effects of performing selected items
• Finalize work for the bridge
• Supports bridge-by-bridge planning
• Takes advantage of Pontis model approach, and
  Pontis recommendations

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Bridge Analysis Interface
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Project Planning Interface

• Graphical management of project information
• Shows Pontis and inspector-generated bridge needs
  simultaneously
• Multiple views of project information
• by project, by bridge
• Customizable presentations
• Powerful query and selection features
• Tracks projects through entire lifecycle

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Database Enhancements

• Eliminate unnecessary data redundancy
• Improve elementhistory storage
• Storing network and bridgeperformance measures
• Support for trackinginspector workrecommendation
  s
• Use of float datatypes for measurements