Parking September 2010 - 46

design-build team often has the flexibility to issue multiple packages for early permit in order to fasttrack the project, because they do not have to wait for the bidding or negotiation phase and can begin construction much sooner. There are risks to this fast-track process, but they are typically borne by the design-builder and the design team—not the owner.

Contrast and Compare
During the design phase, the schedule comparison between design-bid-build and design-build is very similar. Design-build has the advantage, however, after the design is complete and permitted. The bidding and negotiation phase is typically eliminated, and the construction begins immediately after drawings are permitted. Another benefit is that the design team and contractor work in unison during the construction phase instead of at opposing ends. They almost have to, since the design team's client is the contractor. RFIs and changes orders are substantially fewer in design-build projects than in design-bid-build projects. For example, on a recently completed designbuild project, there were a total of 80 RFIs for a 2,470-space parking facility that took approximately 23 months to construct. That’s an average of 40 RFIs per year! In contrast, a smaller 1,900-space facility with the same contractor was delivered as designbid-build and had over 237 RFIs over a 19-month construction period.

The majority of the construction cost in a parking garage is contained in its structure. On average, 65 to 70 percent of a parking garage's construction budget is considered structure-related. These structural elements are typically the items that require the least input from the owner (How many owners do you know that care what the exact stress is in each post tension beam?) and use materials that are very common to the construction industry such as concrete and steel. On a recently completed 2,470-space parking garage, the structural items represented approximately 66 percent of the construction cost. MEP items represented only 7.7 percent, and the architectural elements represented the balance. This garage’s MEP system was considered robust, but not complex in any way, and was comprised entirely of lighting, floor drains and a small HVAC system that provided air conditioning to the electrical, telecommunications and the elevator machine rooms. Budget is only one part of the equation. The parking facility noted above was constructed in approximately 23 months from the time the first pier was drilled until substantial completion was reached. Of this 23-month schedule, the structural frame and precast façade were completed after 16 months, representing approximately 70 percent of the schedule. Compared to an office building of similar square footage, the garage had less risk for price fluctuations because most of the budget was tied up in structural items, which the contractors were able to procure very early in the construction process. If the MEP system represents only seven percent of the construction cost for a parking garage and the price for that system increases substantially, the contractor is able to absorb that price increase much easier than if they were constructing an office building in which the MEP systems could represent upwards of 25 to 30 percent of the construction cost. Design-build benefits the owners because it transfers the risk from the owner to the contractor. Once the guaranteed maximum price is set, there are no change orders, unless they are owner directed. Design-build allows the schedule to be compressed by eliminating the bidding and negotiation phase, and the construction phase is also shortened because the contractor can mobilize crews earlier to the jobsite without having to wait for bids to be received as in a traditional designbid-build format. The quicker schedule saves the owner money on the overall project, since he may be carrying a construction loan (typically with a higher interest rate than permanent financing), and it allows the parking facility to open sooner and begin generating revenue.

Perfect For Parking
Design-build typically isn't suited for complex projects like a medical tower with a curtain wall system and central plant. However, parking garages are the ideal projects to use the design-build delivery method because they have very simple architectural and MEP systems. Their MEP systems typically consist of lighting systems, drains, and fire protection systems, and many of those items are simple in nature and are repetitive on each level of the garage. In a recently completed 1,800-space parking facility for a large university, the design-builder saved the university money and time by having the MEP contractor design and install the entire MEP system. The parking garage was delivered nine months ahead of schedule, from the time 100 percent construction documents were issued to substantial project completion; and under budget, allowing the university to begin generating revenue sooner than expected.

National Parking Association PARKING September 2010

Parking September 2010

Table of Contents for the Digital Edition of Parking September 2010