Condition Assessment. Condition A ssessm ent

Transcription

1 Condition Assessment Definition Condition A ssessm ent A process for rating the physical condition of an asset A process of systematically evaluating an organization s capital assets in order to project repair, renewal, or replacement needs to preserve their ability to support the mission or activities they were assigned to serve Usually a standardized approach for converting distress (e.g. a crack) into overall rating Many assets can be rated through a visual inspection Important for comparing condition of different assets 26/10/2015 Emad Elbeltagi 2 1

2 Definition Condition A ssessm ent Condition assessment is the most important function in asset management process. Its results represent the start point for other functions such as deterioration or repair selection It is worth to mention that, some systems (e.g., RECAPP) can use only the assessment results directly to generate a repair priority list, without using functions for deterioration or detailed life-cycle analysis 26/10/2015 Emad Elbeltagi 3 Why Condition A ssessm ent Avoid premature asset failure, leaving open the option of costeffective repair or rehabilitation Plan for and manage the required level of service Risk management of asset failures and mitigation of consequence of failures Accurate prediction of future expenditure requirements through understanding remaining asset life and capital investment needs 26/10/2015 Emad Elbeltagi 4 2

3 Condition A ssessm ent Condition and Performance Condition describes the physical state of the asset Can be directly measured Has a standard approach to calculate condition rating Used to determine the need and timing of preventative or remedial action to prevent loss of service or economic loss Performance describes how well the service delivered stakeholder needs expectations Measured in terms of reliability, availability, and capacity Used to compare actual performance against service standards or design criteria 26/10/2015 Emad Elbeltagi 5 Condition A ssessm ent Condition and Performance Examples 26/10/2015 Emad Elbeltagi 6 3

4 Condition A ssessm ent Condition Rating system Condition Description 0 Excellent condition, new asset 1 Very good condition No maintenance required 2 Good condition, regular maintenance (5%) 3 Fair condition, maintenance required to return to accepted level of service (15-20%) 4 Poorcondition, major maintenance or renewal (20-40%) 5 Verypoor, asset unserviceable, replacement is required (>50%) 26/10/2015 Emad Elbeltagi 7 Condition A ssessm ent FHWA Bridges Rating system Rating Description 9 Excellent condition, new condition: No noteworthy deficiencies 8 Very Good condition: No repair needed 7 Good condition: some minor problems for minor maintenance 6 Satisfactory condition : some minor deterioration for major maintenance 5 Fair condition: minor section loss, cracking or scour for minor rehabilitation, minor rehabilitation is needed 4 Poor condition: Advanced section loss, deteriorationor scour for major rehabilitation 3 Serious condition: section loss, deteriorationor scour have seriously affected primary structural components for immediate rehabilitation 2 Critical Condition: Advanced deterioration of primary structural elements for urgent rehabilitation. The bridge may be closed until corrective action is taken 1 Imminent failure condition: Major deterioration or section loss present. Bridge may be closed to traffic but corrective action may put back in light service 0 Failed condition: out of service and is beyond corrective action 26/10/2015 Emad Elbeltagi 8 4

5 Condition Assessment Process Develop an asset hierarchy Set the appropriate evaluation mechanism Field inspection (visual, metrics, ) Condition analysis 26/10/2015 Emad Elbeltagi 9 Asset Hierarchy An essential step for condition assessment, a building is hierarchically decomposed into its main components The hierarchy tries to classify and cluster these components under different categories For example, a building can be divided into different disciplines or systems (electrical, mechanical, structural etc.), that can further be divided into a more detailed level till the component level (interior doors, exterior doors, windows, ceiling etc.) The grouping of components into a branch in the hierarchy may be done to reflect similar characteristics (e.g., materials), similar inspection needs, or similar deterioration behavior, etc. 26/10/2015 Emad Elbeltagi 10 5

6 Asset Hierarchy A building could be divided based on its Construction Components (MasterFormat): Steel framing; Masonry walls; Asphalt shingle roof; Carpeted floors, etc. Or based on Functional Components (UniFormat): Foundation; Exterior Walls; Roof; Partitions; HVAC; Lighting, Etc. One of the standard hierarchies used by many researchers is the UNIFORMAT II 26/10/2015 Emad Elbeltagi 11 Asset Hierarchy UniFormat II 26/10/2015 Emad Elbeltagi 12 6

7 Asset Hierarchy UniFormat II 26/10/2015 Emad Elbeltagi 13 Asset Hierarchy: Builder 26/10/2015 Emad Elbeltagi 14 7

8 Asset Hierarchy: RECCAP 26/10/2015 Emad Elbeltagi 15 Condition Evaluation Evaluating the condition of an asset component can be performed by: a distress survey and/or a direct condition rating The distress survey procedure most accurate and reproducible approach. It also provides a record of what's wrong with the inspected component. The direct condition rating is less accurate but faster method for performing a condition survey. It involves visually inspecting each component and evaluating that item against a set of criteria. 26/10/2015 Emad Elbeltagi 16 8

9 Condition Evaluation To decide between the use of a direct rating or a distress survey, it is important to know the purpose of the assessment To merely identify the condition of the component, then the direct condition rating approach is sufficient If the purpose is to identify current problems / failures, then the distress survey approach should be used The values of the condition indices provide means for comparing the condition of various components. 26/10/2015 Emad Elbeltagi 17 Condition Evaluation For a condition index scale from 0 to 100, where 0 represents a critical (failure) condition and 100 represents a new condition. A linguistic representation can be made from the numeric values 26/10/2015 Emad Elbeltagi 18 9

10 Inspection and Data Collection Evaluating the condition for building components using a distress survey requires full knowledge about the deficiencies that the component can suffer from To detect these distresses and measure its severities, a systematic approach for field inspection becomes crucial The mission of the inspection process is to obtain or get the required data to calculate and/or measure the performance or to evaluate the condition 26/10/2015 Emad Elbeltagi 19 Inspection and Data Collection Inspection should be performed in a fashion that is consistent, accurate, and less subjective To standardize the process, check deficiency lists are developed, these lists can be either in a paper form or in an electronic form The inspection process could be done using robots, images, satellite technology, automated devices, and/or smart sensors, Inspection methods could be categorized into four main groups: Visual inspection; Photographic and optical methods; Non-destructive evaluation methods; and Smart sensors. 26/10/2015 Emad Elbeltagi 20 10

11 Inspection and Data Collection Builder deficiency Checklist 26/10/2015 Emad Elbeltagi 21 Inspection and Data Collection Example: Windows deficiencies 26/10/2015 Emad Elbeltagi 22 11

12 Inspection and Data Collection Example: Relative weight of deficiencies 26/10/2015 Emad Elbeltagi 23 Analysis of Inspection Data As the inspection process provides measurements of the severity and density of component deficiencies, some analyses are required to translate these measurements into a condition value. Once the condition of a component is calculated, it is used to calculate the condition at any level in the asset hierarch. Empirical or regression-based formulas are often used to express the component condition based on some critical measurements. Using a deficiency list as used in the BUILDER, field measurements can be easily used to calculate condition index 26/10/2015 Emad Elbeltagi 24 12

13 Analysis of Inspection Data One way of calculating the condition, having a specific list of deficiencies, their weights and their severities. The weights are normalized so that the summation of weights = 100%. 26/10/2015 Emad Elbeltagi 25 Analysis of Inspection Data For example, if a component has four deficiencies D1, D2, D3, & D4 with weights 10, 30, 45, & 15, respectively If the corresponding severities are 25, 30, 10, & 15 then the CI= 100 (10x25+30x30+45x10+15x15)/100 = 81.75, Which implies that the component is in good condition 26/10/2015 Emad Elbeltagi 26 13

14 Pavement Condition Rating (Index) Sewer Pipes Condition Assessment Water Mains Condition Assessment 26/10/2015 Emad Elbeltagi 27 14