Model

Model Maintenance optimisation tool for
reinforced concrete structures

This system is a pilot risk-based model using a generic methodology to allow building owners and consultants to select the most appropriate repair technique for a corroded damaged reinforced concrete structure.

The recommendation of the most appropriate techniques are based on two main parameters:
Time To Corrosion Initiation and the End of Service Life, which can be obtained from the project details.

The model contains tools which can be used for calculating the cost of the selected repair techniques. The selected repair techniques are then compared using a whole life costing analysis tool incorporated within the model.

The Model
- provides guidance on the most appropriate repair strategy
- predicts the residual life of the structure and the time to failure of the repair
- identifies the most cost effective way to meet the client's service life requirements bearing in mind the nature of the structure

The model should not be used for drawing up budgets for repair without consulting an experienced contractor for his\her estimate after looking at the job

The diagram below presents an overall concept on the basic steps in using the model. The model is made up of web pages, which is activated by the various links on the diagram. A brief description of the various links on the diagram is presented in the box below

STEP 1:
This is an introductory page which presents information on the definition of Time to Corrosion Initiation and how it can be assessed using an external tool (DME 5.1) developed within Microsoft Excel. This chapter has two sub sections (Carbonation & Chlorides), these two sections present assistance on how to use the DME 5.1 tool for the associated sub-section.
The main objective of using the DME 5.1 tool is to deduce from the Carbonation or Chlorides Analysis the [Time to Corrosion Initiation] value and use the result within the Repair Strategy Selection tool.

STEP 2:
Repair Strategy Selection: This section  presents a tool and some technical information on how to select the most appropriate repair technique based on the results of the Time to Corrosion Initiation analysis deduced from DME 5.1.
The tool takes as its inputs the source of corrosion (ie. carbonation or chloride), the time to corrosion initiation and year of end of service life.  Based on these inputs, the tool provides a recommendation on the most appropriate repair strategy.

STEP 3:
Repair Techniques Costing: this chapter gives a brief description on all the techniques presented within the system.  Each technique is represented as a sub-section to this chapter. 
Each sub-section presents into detail a description of the technique and also a tool to calculate the cost of applying the technique.

STEP 4:
Comparative Whole Life Costing : this chapter provides a tool to calculate the whole life cycle cost of the project for a given number of years.   It presents a description on how to use the tool and the economic aspect of the output produced from the analysis

The flexibility of the system means that any one of the four main steps can be used, if the appropriate inputs are already known.

This is not a structural tool therefore structural analysis should be carried out if there are concern about overloading or loss of capacity.

For further information, activate this link Guidance Document