Construction

Construction costs in this study are defined as labor, equipment, fuel, and miscellaneous costs, such as road construction warning signage. This cost module does not include materials, as these costs were addressed in the previous section. Separating materials costs from construction costs provides for a more detailed breakdown of the construction

108 _{Material cost estimates for ECC were sourced from Victor Li of the Civil & Environmental}

Engineering (CEE) Department at the University of Michigan.

109 _{Lepech, M.; Li, V.C. “Crack Resistant Concrete Material for Transportation Construction.” Submitted}

“value chain.” Disaggregating the value chain aids in understanding which stage of the life cycle contributes the most to overall construction costs.

4.1.2.1 Model Framework and Parameters

Similar to the module for materials costs, the construction costs module analyzes the CC and ECC systems over the 60-year analysis period across all four construction activities. Appendix B and C provided construction activity and cost information needed to

complete this module. Construction costs for deck replacements, deck resurfacings, and joint/link slab replacements differ between the two systems. The construction cost for a repair is the same between the two systems because they both use the same type and quantity of material (conventional concrete) when a repair is needed. Once the construction costs were determined for each system for each of the 60 years under analysis, these figures were discounted to their present values.

As an example, the calculation for determining construction costs for a CC deck replacement is demonstrated in detail below.

CC Deck Replacement Construction Costs

As calculated in the materials cost module, the square footage of the bridge, less that of the joints is equal to 20,342 square feet. Multiplying this figure by the labor cost per square foot results in the total labor cost of the CC deck replacement.

Labor Cost of Deck Replacement = (Total Sq. Ft. of Bridge) x (Labor Cost per Sq. Ft.) = (20,352 sq. ft.) x ($9 / sq. ft.)

= $183,168

This labor cost figure needed to be disaggregated into two portions, costs attributable to the construction stage and that to the end-of-life stage. Fuel consumption by equipment used for each of these two stages was used as a proxy for separating labor costs into each of these stages. To determine the amount of fuel consumed by equipment, information from the LCI were used. Appendix C states the equipment used in each step of a

construction activity, such as forming a new deck, curing a deck and opening the road to traffic.110 It also includes the amount of days that each machine is needed throughout the construction activity.

The LCI used this information and other model parameters to determine the amount of fuel used by each piece of machinery used for each construction activity. All

construction machinery was assumed to operate on diesel fuel. Several sources were used111, 112, 113, 114, 115 to find the brake horsepower (bhp)116 capability for each machine

110 _{Deconstruction activities associated with the deck replacement (traffic control, removal of link slabs,}

removal of deck) are included in the end of life module.

111 _{South Coast Air Quality Management District. “California Environmental Quality Act Air Quality}

(CEQA) Handbook.” 1993. See http://www.aqmd.gov/ceqa/oldhdbk.html

112 _{El Dorado County, Air Pollution Control District. “Guide to Air Quality Assessment: Determining}

Significance of Air Quality Impacts Under the CEQA.” First Edition. Appendix C-2. February 2002.

113 _{U.S. Environmental Protection Agency. "Nonroad Engine and Vehicle Emission Study Report"}

used. These machines were then categorized into “classes” depending on the amount of bhp offered by a piece of machinery. For example, all machinery with a bhp between 100 and 175 was considered class 6 machinery.117 By using this information, total horsepower-hours needed by each class of machinery were calculated. Fuel efficiencies were needed to determine fuel consumption, as each class of vehicle consumes fuel at different rates.118 For each vehicle class, the product of total horsepower-hours and the corresponding fuel efficiency rates were calculated. By summing the total amount of fuel consumed for each vehicle class, the total amount of fuel consumed by a construction activity was estimated. Table 4.2 below provides a sample calculation for fuel consumed in a deck replacement for the CC system:

Table 4.2 Fuel Consumption for a CC Deck Replacement Vehicle Type Horsepower-hours (hp-hr) Fuel efficiency (L/hp-hr) Fuel Consumption (L) Class 1 88,560 0.223 19,743 Class 7 156,672 0.201 31,417 Class 8 9,600 0.201 1,925 Total 53,085 liters, or 14,024 gallons

Of the 53,085 liters of fuel that went into the CC deck replacement, 37% was used in demolishing the bridge, which means 63% was used for the construction of the bridge; thus the construction portion of the labor cost for a deck replacement is 63% of $183,168, or $115,000.

This same methodology was used to calculate equipment, fuel, and miscellaneous costs, with fuel consumption used to allocate costs to both the construction stage and end-of-life stage.

Separating “Combined” Construction Activities

Some of the construction activities were combined in the LCI. For the ECC system, the LCI considered deck replacements and link slab replacements to be only one construction activity. For the CC system, the LCI combined the deck resurfacing and joint

replacement activities into one construction activity. These LCI “combination”

114 _{U.S. Army Corps of Engineers. “Construction Equipment Ownership and Operating Expense}

Schedule.” Report No. EP 1110-1-8, Volume 2, Chapter 2. July 31, 2003.

115 _{Cooper Concrete. http://www.cooperconcrete.com/concretefaq.htm#How. Accessed: March 27, 2004.} 116 _{Bhp measures the amount of useful horsepower of an engine. Source: Bartleby.com.}

http://www.bartleby.com/61/14/B0451400.html. Date accessed: November 5, 2003.

117 _{U.S. Environmental Protection Agency. "Exhaust and Crankcase Emission Factors for Nonroad}

Engine Modeling – Compression-Ignition." Assessment and Modeling Division, Office of Transportation and Air Quality Report No. EPA420-P-02-016, NR-009b. November 2002. This document can be found at: http://www.epa.gov/otaq/models/nonrdmdl/p02016.pdf See Appendix C for a complete list of the equipment bhp classifications.

118 _{In this case, fuel efficiency for each machinery class was determined based on brake specific fuel}

consumption (BSFC). BSFC measures “an engine’s efficiency based on fuel consumption.” Source: http://www.westechperformance.com/pages/Tech_Library/Understanding/bsfc.html. Westech

construction activities needed to be separated for construction costs to be calculated for each individual construction activity.

Again, fuel consumption information from the LCI can be used as a proxy to separate the costs of these “combined” construction activities. Table 4.3 below presents ECC data, which is used to separate fuel consumption from the LCI “combination” activity into fuel for the deck replacement and fuel for the link-slab replacement.

Table 4.3 Construction Fuel Consumption for an ECC Deck Replacement and Link-Slab Replacement

Fuel Consumed (in Liters) % of Total

Deck replacement 49,877 91%

Link slab replacement 4,815 9%

LCI “Combination” Construction Activity: Deck replacement-link slab replacement

54,692 100%

Fuel consumption for the link slab replacement was obtained by screening the equipment used in the LCI “combined” construction activity and tallying only those line-items that related to the link slab. These line-items total 4,815 liters or 9% of the total amount of fuel for this LCI “combination” construction activity. The deck replacement was handled in the same manner and represented 91% of the total fuel costs for the LCI “combination” construction activity.

The resurfacing and joint replacement activities in the CC system were also combined in the LCI; thus allocating construction costs to each of these construction activities was handled in the same manner.

To calculate the overall construction cost associated with a construction activity, the labor, equipment, fuel, and miscellaneous costs were summed. While the example above calculates construction costs for a CC deck replacement, this method for calculating construction costs was also used for resurfacing and joint/link-slab replacement construction activities.

Repairs Construction Costs

Calculations for repairs required a different approach because of the types of data available. As discussed in the materials module, the contractor put forth an estimate of $200/cubic yard (cyd) for repairs, which included materials, equipment, labor, fuel and miscellaneous construction costs. Subtracting the $144/cyd for materials leaves $56/cyd for repair construction costs. Multiplying this figure by the 3.27 cubic yards of concrete needed for repairs yields a total construction cost (excluding materials) for a repair construction activity of $183. The cost of a repair activity is the same between both systems, but since there are fewer repairs for the ECC system over the 60-year analysis period, construction costs for repairs are lower for the ECC system.

4.1.2.2 Data Quality, Uncertainties and Limitations

With regard to fuel costs, this module assumes that a set amount of fuel is consumed for each horsepower-hour a particular piece of construction equipment is used. In reality, some equipment may sit idle over the course of a day. Thus, even if two pieces of machinery are categorized in the same equipment class, one may idle more frequently, which would result in less fuel costs. Since fuel consumption is used as a proxy for labor, equipment, and miscellaneous construction costs, incorporating idle time could also affect these construction costs, not just fuel costs. This level of detail for equipment usage is beyond the scope of this analysis.

With the LCI using many different sources for information, it is possible that there could be inconsistencies in the data. Data for bhp and fuel efficiencies were obtained from several sources. Results may be more consistent but less accurate when they are cited from a single source rather than several sources. There will also be some variation associated with the construction equipment and construction time schedule provided by the Michigan construction company. The amount of time needed to complete a

construction activity can vary between contractors, depending on the number of

personnel and materials available, weather patterns, and construction processes used. In addition, construction contractors may use different types of equipment than that

recommended by the Michigan construction company used for this study. Nonetheless, the Michigan construction company used for this study is well regarded by many in the industry and provided information that is believed to be as consistent with its

construction experience as possible.