This page presents a tool to compare the various repair techniques based on the output produced by the present value of the life cycle cost for the two options as well as the equivalent uniform annual cost.

Analysis of the inputs submitted to the tool will identify the most cost effective repair techniques(s) to be used.

The output generated by this WLC tool   is based on the assumption that the cost of future repairs as well as the maintenance cost is constant for the duration of the study period. 

Net Present Value: this compares the value of  today’s money with the value of the same money in the future, after taking the discount and inflation rate into account.

Equivalent Uniform Annual Cost: this is the same amount of money set aside each year over the duration of the study period.

 
Alternatively activate this URL http://projects.bre.co.uk/wlccomparator for more information on whole life costing.

Below is a brief description Ref: Economics of Parking Garage Rehabilitation by Mazzuca, M et Walker, C on the inputs required to calculate the present value of the life cycle cost and its equivalent uniform annual cost:

Study Period : this is basically the design life of the structure upon which the repair technique being used is to be evaluated.

Cost of Initial Repairs: this is the total cost for applying the specified technique.  These include cost incurred for all required repairs, contingency, etc.  This can be obtained by using the tool associated with the specified repair technique presented in the sub sections under  Repair Techniques Costing .

Interval Period for Future Repairs:   Allowance is to be made for time interval period where repairs will be needed for the duration of the study period.

Cost of Future Repairs: The cost of the repairs to be undertaken at the set time intervals has to be estimated.  The estimate will be attributed to the knowledge of the project as well as the expertise of the engineers.

Salvage Cost: The salvage cost remaining at the end of the evaluation will also have to be estimated.

Annual Maintenance:   The cost for undertaking annual maintenance is also estimated.

Interest Rate:   This is the percentage at which today's money will gain tomorrow.

Inflation / Discount Rate:   This is the percentage rate which determines how much today's activities will cost tomorrow.