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Concrete Beam Economics

Concrete Beam Economics. Bob Lawrence Alan Schuetz James Giancaspro Mark McDonnell. Agenda. Problem Statement Concrete Assumptions Example of Spreadsheet Program Economics of a Concrete Beam Alternative Solutions Concrete Steel Economic Assumptions for Concrete and Steel

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Concrete Beam Economics

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  1. Concrete Beam Economics Bob Lawrence Alan Schuetz James Giancaspro Mark McDonnell

  2. Agenda • Problem Statement • Concrete Assumptions • Example of Spreadsheet Program • Economics of a Concrete Beam • Alternative Solutions • Concrete • Steel • Economic Assumptions for Concrete and Steel • Costs for Concrete and Steel Beams • Conclusion

  3. Problem Statement • To develop a cost analysis of a concrete beam using multiple parameters and compare the final cost with alternative methods

  4. Concrete Beam length shall be from 0’ to 50’ Water, Sand, Aggregate and Steel will have constant unit prices. The price of water came from the Seattle Public Works. The prices for Sand, Steel and Aggregate were taken from Engineering News Report. The unit prices for Sand, Aggregate and Steel are calculated through a 20 city average. Economic Assumptions Concrete

  5. Only three types of concrete beams will be studied: Box, T, and L Concrete Beams have a life span of 50 years Labor cost will be the same for all 3 types Concrete beams require negligible maintenance At the end of 50 years the beam has no salvage value and is recycled Concrete Economic Assumptions Cont.

  6. Spreadsheet Presentation

  7. Spreadsheet Economics • 10’ Beam • Total Material Cost For A Box Beam $108.46 • Total Material Cost For A T-Beam $54.07 • Total Material Cost For A L-Beam $59.55 • 20’ Beam • Total Material Cost For A Box Beam $496.02 • Total Material Cost For A T-Beam $243.12 • Total Material Cost For A L-Beam $271.65

  8. Spreadsheet Econ. Cont. • 40’ Beam • Total Material Cost For A Box Beam $2,515.91 • Total Material Cost For A T-Beam $1,194.46 • Total Material Cost For A L-Beam $1,388.35 • 50’ Beam • Total Material Cost For A Box Beam $4,248.96 • Total Material Cost For A T-Beam $2,049.36 • Total Material Cost For A L-Beam $2,325.37

  9. Alternatives • Steel Beams • Wood • Plastic Lumber

  10. Alternative Cont. • We only considered Steel because Plastic Lumber is still in the developmental stage and the amount of Wood needed to hold an equal load is impractical

  11. Benefits Cheap Materials Can hold same load as Steel Durable Low Maintenance No Finishing Required Negatives Shorter life span Doesn’t allow for taller structures Concrete cannot take tensile force Concrete

  12. Benefits Long Life span Has Salvage value Allows for taller structures Works equally as well in tension and compression Negatives High Maintenance More expensive than concrete Steel

  13. Safety and Strength for steel and concrete beams will be set equal so there will be an even comparison Installation cost for steel and concrete beams are the same When disassembled neither will have an effect on the environment so that will not be considered. Assume 3 Masons can construct a concrete beam in 1 hour (pre-molded) Assumptions for Concrete/Steel Comparison

  14. Steel beam must be painted every 7 years or they will rust We will terminate our economic comparison at 49 years so the study times will be equal MARR 10% The spreadsheet program assumes all steel is 60 ksi. The price of steel is a national average. The current recycling value of steel is $90.00/ton Assumptions Cont.

  15. Steel Beams • There are only two steel beam that can hold the 10,000 lb. live and dead load we have specified for the concrete beams • They are the: W36 - 848 W36 - 798

  16. Concrete Beam 50’ in length Total Material Cost For a Box Beam $4,248.96 Total Material Cost For a T-Beam $2,049.36 Total Material Cost For a L-Beam $2,325.37 Steel Beam 50’ in length W36- 798 $25,935 W36- 848 $27,560 Materials Cost Comparison

  17. Maintenance Concrete • Concrete Beam • Maintenance cost is very near zero

  18. Maintenance Steel • Steel must be painted every 7 years • Assume 2 painters can cover 3,600 sq. ft per day • They are paid $.11 per sq. ft. • Paint cost $.05 per sq. ft. • One beam’s cost are: Labor: $396 Paint: $90

  19. Labor Cost Concrete • Labor Cost for Concrete and Steel are the same except for the beam must be formed out. • Assume 3 masons per beam • Assume Mason Labor Rate: $27.52/hour • Cost per beam: $82.56

  20. Concrete Concrete has salvage value of approximately zero Steel 50’ Length W36- 848 Salvage Value: $1908 W36 - 798 Salvage Value: $1795.5 Salvage Value

  21. Concrete Annual Worth Labor $8.33 Materials Box $428.72 T $206.78 L $234.63 Salvage $0 Maintenance $0 Steel Annual Worth Materials W36- 848 $2616.84 W36- 798 $2780.80 Maintenance Both beams $238.73 Salvage W36- 848 $1.72 W36-798 $1.62 Cost ComparisonPer 50’ Beam

  22. Total Costs • Total Costs • Concrete • Box -$437 • T -$215.16 • L -$243 • Steel • W36- 848 -$3017.81 • W36- 798 -$2853.95

  23. Conclusion • The main purpose of our project was to set up a Spreadsheet that calculates material prices for concrete beams • Although through comparison our recommendation would be for Concrete Beams

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