IMPORTANT: This module is intended to be a decision support tool and should not be solely relied upon for determining the inspection interval, i.e. a certain degree of engineering judgement should be applied while putting the model output into practice. It is advisable that the module is operated after the report 'Risk Based Inspection for Highway Structures', which explains, in detail, the adopted methodology and the intended use of the model, has been carefully read and understood.Each structure has it's own Risk Based Inspection Information. Users can set inspection costs, PI intervals and Failure/Deterioration levels. To view this information first
open a structure that you are interested in, the click on
Inspections on the
Structure menu.
Field | Explanation |
Road used | Determined automatically from the carried field on the structure details |
Obstacle Crossed | Determined automatically from the crossed field on the structure details |
Primary Deck Form | Determined automatically from the most recent inspection |
Primary Deck Material | Determined automatically from the most recent inspection |
BCI Average | Determined automatically based upon the lasted condition scores |
BCI Critical | Determined automatically based upon the lasted condition scores |
Rate of Deterioration | Determined automatically based upon the Primary Deck Form and Material. More details here |
Extent of Failure | Requires engineering input from the user |
User Defined Rate of Deterioration | Requires engineering input from the user |
Exposure | Requires engineering input from the user |
Potential Failure Mode | Requires engineering input from the user |
Inspectability Consideration | Requires engineering input from the user |
Inspection Costs - This section is only visable for user's with a high permission level for the RBI module. The section enables users to set inspection and access costs.
Risk Based Inspection ScoresThe risk posed by a group of structures, an individual structure and/or an element of very high importance (as defined by the CSS inspection procedure[8]) due to deterioration or damage is evaluated as a function of the
probability and
consequence of rapid deterioration, damage or failure.
The risk score and associated rating is obtained from the table below while the risk based inspection intervals are derived based on the risk rating and the table below.
| | Probability of Rapid Deterioration, Damage or Failure |
Consequence of Failure | Very Low 1 – < 30 | Low 30 – < 50 | Moderate 50 – < 70 | High 70 – < 90 | Very High 90 – 100 |
Very Low 1 – < 10 | Very Low 1 | Very Low 15 | Low 25 | Moderate 40 | Moderate 60 |
Low 10 – < 30 | Very Low 15 | Low 25 | Moderate 40 | Moderate 50 | High 70 |
Moderate 30 – < 50 | Low 25 | Low 30 | Moderate 50 | High 70 | High 80 |
High 50 – < 70 | Low 30 | Moderate 40 | Moderate 60 | High 80 | Very High 90 |
Very High 70 – 100 | Moderate 40 | Moderate 60 | High 80 | Very High 90 | Very High 100 |
Risk Rating | Alterations to Principal Inspection Interval |
Very Low | Increase the Principal Inspection interval |
Low | Increase the Principal Inspection Interval |
Moderate | Maintain the Principal Inspection Interval |
High | Reduce the Principal Inspection Interval |
Very High | Reduce the Principal Inspection Interval |
A risk rating of ‘Very Low’, ‘Low’ and ‘Moderate’ is considered to represent structures that have inspection intervals which are broadly acceptable or negligible in terms of risk mitigation. This does not preclude the analysis being repeated for structures with ‘Very Low’ and ‘Low’ risk ratings with an appropriately increased inspection interval so that the associated resulting risk rating would be ‘Moderate’. A risk rating of ‘High’ and ‘Very High’ represents structures that pose critical risk(s) and are considered to have inappropriate inspection intervals. For these structures the analysis should be repeated with an appropriately decreased inspection interval so that the associated resulting risk score would be ‘Moderate’.
The other associated scores and factors calculated as part of the Risk Score are described in their own knowledge base articles.
Potential Failure Mode ScoreProbability of Rapid DeteriorationCurrent Condition ScorePrincipal Inspection Adjustment FactorConsequence of Failure ScoreMagnitude of Failure ScoreSocio Economics ImportanceInspection IntervalThis section includes the
proposed (calculated) PI Interval which is automatically calculated by the system. The interval is assessed for it's risk score then increased or decreased until a moderate risk score is acheived.
The upper and lower limits are also automatically calculated by assessing varying interval lengths. The lower limit represents the limit of a high risk rating for the structure, whilst the upper limit represents the limit of a low risk rating.
This section can also be used to set a user defined Altered PI Interval, this will override the automatically calculated interval. A reason for using a user defined must be recorded.
Inspection InformationThis section displays the last PI and GI dates from the inspections (actual) folder. The next PI and GI dates are also displayed, these are based upon the current final inspection programme developed using the Inspection Programme module.