Concrete Beam EconomicsConcrete Beam Economics

Bob LawrenceBob Lawrence

Alan SchuetzAlan Schuetz

James GiancasproJames Giancaspro

Mark McDonnellMark McDonnell

AgendaAgenda

Problem StatementProblem Statement Concrete AssumptionsConcrete Assumptions Example of Spreadsheet ProgramExample of Spreadsheet Program Economics of a Concrete BeamEconomics of a Concrete Beam Alternative SolutionsAlternative Solutions ConcreteConcrete SteelSteel Economic Assumptions for Concrete and SteelEconomic Assumptions for Concrete and Steel Costs for Concrete and Steel BeamsCosts for Concrete and Steel Beams ConclusionConclusion

Problem StatementProblem Statement

To develop a cost analysis of a To develop a cost analysis of a concrete beam using multiple concrete beam using multiple parameters and compare the final parameters and compare the final cost with alternative methodscost with alternative methods

Economic Assumptions Economic Assumptions ConcreteConcrete

Concrete Beam Concrete Beam length shall be from length shall be from 0’ to 50’0’ to 50’

Water, Sand, Water, Sand, Aggregate and Steel Aggregate and Steel will have constant will have constant unit prices.unit prices.

The price of water The price of water came from the came from the Seattle Public Seattle Public Works.Works.

The prices for Sand, The prices for Sand, Steel and Steel and Aggregate were Aggregate were taken from taken from Engineering News Engineering News Report. Report.

The unit prices for The unit prices for Sand, Aggregate Sand, Aggregate and Steel are and Steel are calculated through calculated through a 20 city average.a 20 city average.

Concrete Economic Concrete Economic Assumptions Cont.Assumptions Cont.

Only three types of Only three types of concrete beams will concrete beams will be studied: Box, T, be studied: Box, T, and Land L

Concrete Beams Concrete Beams have a life span of have a life span of 50 years50 years

Labor cost will be Labor cost will be the same for all 3 the same for all 3 typestypes

Concrete beams Concrete beams require negligible require negligible maintenancemaintenance

At the end of 50 At the end of 50 years the beam years the beam has no salvage has no salvage value and is value and is recycledrecycled

Spreadsheet PresentationSpreadsheet Presentation

Spreadsheet EconomicsSpreadsheet Economics

10’ Beam10’ 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

Spreadsheet Econ. Cont.Spreadsheet Econ. Cont.

40’ Beam40’ 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’ Beam50’ 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

AlternativesAlternatives

Steel BeamsSteel Beams WoodWood Plastic LumberPlastic Lumber

Alternative Cont.Alternative Cont.

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

ConcreteConcrete

BenefitsBenefits– Cheap MaterialsCheap Materials– Can hold same Can hold same

load as Steelload as Steel– DurableDurable– Low MaintenanceLow Maintenance– No Finishing No Finishing

RequiredRequired

NegativesNegatives– Shorter life spanShorter life span– Doesn’t allow for Doesn’t allow for

taller structurestaller structures– Concrete cannot Concrete cannot

take tensile forcetake tensile force

SteelSteel

BenefitsBenefits– Long Life spanLong Life span– Has Salvage valueHas Salvage value– Allows for taller Allows for taller

structuresstructures– Works equally as Works equally as

well in tension and well in tension and compression compression

NegativesNegatives– High MaintenanceHigh Maintenance– More expensive More expensive

than concretethan concrete

Assumptions for Assumptions for Concrete/Steel Concrete/Steel

ComparisonComparison

Safety and Strength Safety and Strength for steel and for steel and concrete beams will concrete beams will be set equal so be set equal so there will be an there will be an even comparisoneven comparison

Installation cost for Installation cost for steel and concrete steel and concrete beams are the beams are the samesame

When disassembled When disassembled neither will have an neither will have an effect on the effect on the environment so environment so that will not be that will not be considered.considered.

Assume 3 Masons Assume 3 Masons can construct a can construct a concrete beam in 1 concrete beam in 1 hour (pre-molded)hour (pre-molded)

Assumptions Cont.Assumptions Cont.

Steel beam must be Steel beam must be painted every 7 painted every 7 years or they will years or they will rustrust

We will terminate We will terminate our economic our economic comparison at 49 comparison at 49 years so the study years so the study times will be equaltimes will be equal

MARR 10%MARR 10%

The spreadsheet The spreadsheet program assumes program assumes all steel is 60 ksi.all steel is 60 ksi.

The price of steel The price of steel is a national is a national average.average.

The current The current recycling value of recycling value of steel is $90.00/tonsteel is $90.00/ton

Steel BeamsSteel Beams

There are only two steel beam that There are only two steel beam that can hold the 10,000 lb. live and can hold the 10,000 lb. live and dead load we have specified for dead load we have specified for the concrete beamsthe concrete beams

They are the:They are the:

W36 - 848W36 - 848

W36 - 798W36 - 798

Materials Cost ComparisonMaterials Cost Comparison

Concrete BeamConcrete Beam 50’ in length50’ 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 BeamSteel Beam 50’ in length50’ in length W36- 798W36- 798

$25,935$25,935 W36- 848W36- 848

$27,560$27,560

Maintenance Concrete Maintenance Concrete

Concrete BeamConcrete Beam Maintenance cost is very near zeroMaintenance cost is very near zero

Maintenance Steel Maintenance Steel

Steel must be painted every 7 yearsSteel must be painted every 7 years Assume 2 painters can cover 3,600 sq. Assume 2 painters can cover 3,600 sq.

ft per dayft per day They are paid $.11 per sq. ft.They are paid $.11 per sq. ft. Paint cost $.05 per sq. ft.Paint cost $.05 per sq. ft. One beam’s cost are:One beam’s cost are:

Labor:Labor: $396$396

Paint:Paint: $90 $90

Labor Cost ConcreteLabor Cost Concrete

Labor Cost for Concrete and Steel Labor Cost for Concrete and Steel are the same except for the beam are the same except for the beam must be formed out.must be formed out.

Assume 3 masons per beamAssume 3 masons per beam Assume Mason Labor Rate: Assume Mason Labor Rate:

$27.52/hour$27.52/hour Cost per beam:Cost per beam:

$82.56$82.56

Salvage ValueSalvage Value

ConcreteConcrete Concrete has Concrete has

salvage value of salvage value of approximately approximately zerozero

SteelSteel 50’ Length50’ Length W36- 848W36- 848

Salvage Value: $1908Salvage Value: $1908 W36 - 798W36 - 798

Salvage Value: Salvage Value: $1795.5$1795.5

Cost ComparisonCost ComparisonPer 50’ BeamPer 50’ Beam

Concrete Annual Concrete Annual WorthWorth

Labor $8.33Labor $8.33 MaterialsMaterials

– BoxBox $428.72$428.72– TT $206.78$206.78– LL

$234.63$234.63 Salvage $0Salvage $0 Maintenance $0Maintenance $0

Steel Annual WorthSteel Annual Worth MaterialsMaterials

– W36- 848 $2616.84W36- 848 $2616.84– W36- 798 $2780.80W36- 798 $2780.80

Maintenance Maintenance – Both beams $238.73Both beams $238.73

SalvageSalvage– W36- 848 $1.72W36- 848 $1.72– W36-798 $1.62W36-798 $1.62

Total CostsTotal Costs

Total CostsTotal Costs ConcreteConcrete

– BoxBox -$437-$437– TT -$215.16-$215.16– LL -$243-$243

SteelSteel– W36- 848 -$3017.81W36- 848 -$3017.81

– W36- 798W36- 798 - -$2853.95$2853.95

ConclusionConclusion

The main purpose of our project The main purpose of our project was to set up a Spreadsheet that was to set up a Spreadsheet that calculates material prices for calculates material prices for concrete beamsconcrete beams

Although through comparison our Although through comparison our recommendation would be for recommendation would be for Concrete BeamsConcrete Beams