LCC Methodology Hkan Sundquist Structural Design and Bridges

LCC Methodology Håkan Sundquist Structural Design and Bridges KTH ETSI Methodology 1

There are many requirements on a bridge ETSI Methodology 2

The classic task ETSI Methodology 3

The classic bridge design task ETSI Methodology 4

LCC optimization ETSI Methodology 5

Include maintenance and operation costs ETSI Methodology 6

Agency or owner costs ETSI Methodology 7

The bridge must also contribute economically to the society ETSI Methodology 8

Include society costs during maintenance and repair Include eventual accident costs ETSI Methodology 9

User benefit and cost ETSI Methodology 10

Costs for the society due to accidents and total failure n Accidents are usually covered by the society and not by agencies like SRA or Finn. RA ETSI Methodology 11

LCC n Life Cycle Costing LCC is a technique which enables comparative cost assessments to be made over a specified period of time, taking into account all relevant economic factors n n initial capital costs future operational and maintenance costs n n owner costs user costs society costs future disposal cost n Used methodology is usually the present value of the total cost of this asset over its lifetime ETSI Methodology 12

LCC scheme ETSI Methodology 13

Definitions n LCC owner or agency n LCC = LCCA + LSC + LCCC n LCCA = is the cost for acquisition of the project (design, construction…) by the net present value calculated to a specified time usually the opening of the bridge n LSC = (Life Support Cost) is the cost for future operation, maintenance and repair of the bridge, by the net present value calculated to a specified time usually the opening of the bridge. n LCCC = (Life Cycle Cost Consequence), is the future costs for eventual negative consequences, by the net present value calculated to a specified time, usually the opening of the bridge. ETSI Methodology 14

LSC, the Life Support Cost n LSC = CI + CN n CI = is the investment in the necessary equipment and other resources for the future operation and maintenance n CN is the future cost for operation, maintenance and repair, by the net present value calculated to a specified time, usually the opening of the bridge n The investment part of the maintenance, CI, could be divided in parts ETSI Methodology 15

CI = Investment for operation and maintenance n CI = CIr + CIv + CId + CIt n CIr = spare parts and material n CIv = instrument, tools, vehicles that is needed for inspection and maintenance n CId = documentation i. e. drawings and instruction manuals needed for inspection and maintenance n CIt = education of personnel for operation and maintenance ETSI Methodology 16

The costs are recalculated to one point in time usually the day of opening the bridge • Ct the sum of all costs incurred at time t, • p the real interest rate or a rate taking into account changes in the benefit of the structure and • t is the time period studied, typically for a structure for the infrastructure the expected life span. ETSI Methodology 17

Interest rate p. L interest rate for loans with long duration pi inflation pc increase of usefulness of the bridge i. e. increase of traffic ETSI Methodology 18

Net present cost for a cost of value=1, 0 year 0 ETSI Methodology 19

User cost delay L vr vn ADTt Nt r. L w. L T length of affected roadway the traffic speed during bridge work activity the normal traffic speed the average daily traffic, i. e. cars per day at time t the number of days of road work at time t the amount of commercial traffic is the hourly time value for commercial traffic the hourly time value for drivers studied time interval T ETSI Methodology 20

User costs, operation New notations: o. L operating cost for the commercial traffic vehicles o. G operating cost for transported goods o. D operating cost for cars T time interval ETSI Methodology 21

Societal costs, accidents and failure New notations: An the normal accident rate per vehicle-kilometres Ar the accident rate during roadwork Cacc the cost for each accident for the society Rj probability for a specified failure coupled to KH, j cost for failure (One value for ultimate limit state and one for serviceability limit state) For normal bridges the probability of failure is so small that it could be omitted in the analysis! 22 ETSI Methodology

Valuation n Degradation models n Knowledge on interest rents (100 year!!) n Knowledge about the future of the traffic system! (will the traffic increase or decrease? ? ) n Knowledge on costs for n n operation, maintenance, inspection and repair ETSI Methodology 23

“Soft values” must also be included ETSI Methodology 24

Environmental issues must also be included! ETSI Methodology 25

Parameters needed for the LCC analysis n Methodologies for dividing the bridge into different parts and giving measures of the components n Costs for construction and repair different parts of the bridge n Yearly operating costs n Actions in time for MR&R actions n Cost for disposal of the bridge n User and societal costs ETSI Methodology 26

Suggestion for bridge parts ETSI Methodology 27

Bridge parts and measures ETSI Methodology 28

Cross-section definitions ETSI Methodology 29

Foundation ETSI Methodology 30

Materials for LCC OBS, LCA requires added material definitions! ETSI Methodology 31

Costs n Cost parameters should be given by the agencies hopefully in data bases updated every year!? Costs for construction n Cost for MR&R actions n Parameters for calculating the user costs n Societal costs n… n ETSI Methodology 32

Definition of actions n Management n Operation n Inspections n Repair n Upgrading n Final demolition and disposal ETSI Methodology 33

Operation n Management is the owners own work for keeping the bridge inventory, the planning and other actions to manage the bridge stock. Usually this work can be assigned as percentage of the actual value to re-build the bridge stock. n Operation is the yearly work to superficially and regularly inspect, clean, repair small damages of the bridges. The Swedish term is “Drift” ETSI Methodology 34

Examples of operation (yearly) actions Examples of “operation maintenance actions”. In the Swedish system this is called “Egenskaper” or “properties” ETSI Methodology 35

Time between different MR&R actions n. Needed parameters: n Life span n Yearly operation actions n Time interval between inspections n Time between maintenance and repair ETSI Methodology 36

Methods for judging time between MR&R actions 1. Mechanistic or chemical models 2. Evaluation results from large field observations, 3. The up to day most applied method is to use experience from specialists, usually people deeply involved with inspection of bridges ETSI Methodology 37

LCC With everything in hand it is just to calculate the LCC for a bridge or maybe all bridges in a county or for a road network!! ETSI Methodology 38

GOOD LUCK! Trying and commenting our programs! ETSI Methodology 39