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Assumptions made in this analysis are outlined below.
Directional Boring • yDue to the conduit separation requirements for AT & T, FPL, and Comcast infrastructure, a typical installation within the roadway by directional bore would require a minimum of three separate bores, each containing multiple conduits— FPL primary / service conduit, AT & T mainline / service conduit, and Comcast mainline / service conduits. FPL feeder conduit may or may not be bored separately from the other FPL primary / service conduits depending on the site-specific factors.
• yRestoration will be required at each“ bore pit” and within areas of the roadway that need to be excavated to intercept primary conduits for transformers, feeder conduits for switches, and service conduits for each building. One restoration area per property was assumed in the analysis.
Open Cut • yThis method assumes AT & T, FPL, and Comcast infrastructure will be installed in a joint trench with the required separation between each utility. Asphalt trench repair is assumed to be required for most joint trench installations as the opportunities for an off-roadway joint trench installation within the Town is limited due to right of way and property improvement restrictions.
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Based on these assumptions, costs for installing a typical conduit run by directional bore was estimated to carry an appreciably higher cost than installation of those same conduits within a joint trench via the open-cut installation method, despite the lack of pavement repair required. Additionally, there are technical challenges with boring on many of the Town’ s roadways that can be overcome using the open cut method.
These challenges include:
• yNarrow rights of way with a high level of utility congestion.
• ySignificant number of electrical and communications conduits to occupy a corridor with very limited space.
• ySpacing requirements between electrical and communications facilities that would require separate bores.
• yBore spacing required for constructability to prevent multiple bores from converging together as often happens in sandy conditions and tight spacing.
Based on the analysis above, it is assumed by this opinion of probable cost that open-trench installation methods will be used for most of the joint trench conduit installation within
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Town right-of way. It is further assumed the FPL service conduit installation on private property will be installed via directional bore to minimize private property disturbances and related restoration costs for the many high-end finishes that exist on private property. It is assumed AT & T and Comcast service can be installed as direct bury cable on private property. FPL service conduit was assumed to be installed as a separate bore to maintain the required separation to avoid electromagnetic interference issues.
An exception to this may be Phase 1 South( south of Sloan’ s Curve). This project area has a wide right-of-way with large properties that create long distances between service points. Because most properties are large, multi-family condominiums there is relatively little service conduit to be installed. Most runs are anticipated to be either feeder or primary electric and / or communications backbone. This reduces the number of entry / exit pits required throughout the area which in turn reduces the anticipated cost of bore machine setups related to directional boring. This combined with the general desire to disturb as little landscaping as possible could create a situation where directional boring becomes more technically feasible and the related costs are less than or comparable to an open cut conduit installation. For this reason, directional bore construction methods have been assumed for most of Phase 1 South. However, in order to allow the contractor the greatest freedom to achieve the lowest cost
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installation with the greatest schedule efficiency, the decision whether to bore or trench will be left to the construction team.
12.7.4 Electrical and Communications Utility Systems
• yUnderground electrical and communications facilities to be constructed under this program are anticipated to be significantly different from their overhead counterparts based on the nature of an underground system design and layout. However, costs related to“ betterment” or system upgrades are assumed to be the responsibility of the utility owner. For example, feeder ties that exist today would be replaced underground in-kind at a cost to the Town. New feeder ties that do not currently exist that are intended to enhance system reliability could be installed at a cost to the utility owner.
• yElectrical system costs consider a mix of“ Vista” and FPL standard switch gear. The opinion of cost considers that 90 percent of the switchgear will be standard style with the remainder being Vista style when specific site conditions dictate the use of the Vista cabinet.
• y“ Like-for-Like” copper coaxial systems were considered in this opinion of cost for the undergrounding of telephone facilities. It is understood from AT & T that the existing at-grade equipment cabinets will be reused. It is further
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