4.2 Project Delivery Systems and Contract Pricing Structures

Every construction project requires two foundational structural choices by the project owner: (1) the Project Delivery System, which defines the contractual relationships, lines of communication, and division of design and construction responsibilities among the Owner, Designer, and Builder; and (2) the Contract Pricing Structure, which establishes how the contractor is compensated and how the financial risks of cost overruns and quantity variations are allocated between the parties.

The Four Major Project Delivery Systems

1. Traditional Design-Bid-Build (DBB)

Design-Bid-Build (DBB) is the classic, sequential delivery method used across public works and conventional commercial construction:

• Two Separate Contracts (No Privity Between A/E and Contractor): The Owner executes two separate contracts: first, a professional services agreement with an Architect or Engineer (A/E) to prepare 100% complete working drawings and technical specifications; second, a construction contract with a Prime Contractor selected after competitive bidding. There is no direct contractual relationship (no privity of contract) between the Architect and the Prime Contractor.
• Linear Sequence and Checks & Balances: Traditional Design-Bid-Build generally bids the completed design for each construction package and follows a sequential schedule (Design $\rightarrow$ Bid $\rightarrow$ Build), which can take longer than overlapping design and construction; separately completed packages can still allow phased work. Its primary advantage to the Owner is clear upfront price competition on a complete design and independent quality oversight by the Architect during construction.
• The Spearin Doctrine (United States v. Spearin): Because the Owner hires the Architect and furnishes completed plans and specifications to bidders in Design-Bid-Build, the Owner impliedly warrants that the plans and specifications are accurate, free from design defects, and suitable for their intended purpose. Under the Spearin Doctrine, a contractor who builds strictly in accordance with owner-furnished design specifications is not liable if the completed system fails to perform due to a design flaw, and is entitled to a compensable Change Order to correct the defective design.

2. Design-Build (DB)

In a Design-Build delivery system, the Owner executes a single contract with a single Design-Build entity (an integrated design-build company, a prime contractor subcontracting with an architectural firm, or a contractor-architect joint venture) that assumes single-point responsibility for both architectural/engineering design and physical construction.

• Single Point of Responsibility: The Owner is never caught in the middle of finger-pointing disputes between an independent architect blaming workmanship and a contractor blaming defective plans—the Design-Builder is legally responsible for both.
• Fast-Track (Phased) Construction: Because design and construction are controlled under one roof, Design-Build enables Fast-Track construction, in which early construction packages (site clearing, mass grading, underground utilities, and deep foundations) begin in the field while structural steel, MEP systems, and interior finishes are still being designed. Fast-tracking significantly compresses the overall schedule from concept to occupancy, though it increases the risk of costly rework if late design changes conflict with foundation work already in place.

3. Construction Management: Agency CM vs. CM at Risk (CMAR)

Professional Construction Management (CM) introduces construction expertise during the design phase (constructability reviews, value engineering, cost estimating, and long-lead scheduling), but exists in two legally distinct forms:

• Agency Construction Management (CM as Advisor / CMa): The Agency CM acts purely as the Owner's fee-based consultant and advisor. An Agency CM does not perform construction work, does not hold subcontracts (the Owner signs separate contracts directly with multiple trade contractors or a general contractor), and does not guarantee the project's final cost or completion date. The Owner retains the financial risk of trade contractor default and cost overruns.
• Construction Manager at Risk (CMAR / CMc): The CMAR acts as an advisor during the pre-construction design phase for a pre-construction fee, and then steps into the legal shoes of a Prime Contractor during the construction phase. Unlike an Agency CM, a CM at Risk holds all trade subcontracts directly in its own name, assumes legal liability for trade performance and schedule, and typically guarantees that total construction costs will not exceed a negotiated Guaranteed Maximum Price (GMP).

4. Turnkey / EPC (Engineering-Procurement-Construction)

A Turnkey project is an expanded form of Design-Build—frequently used in industrial plants, power generation, and commercial real estate development—in which a single Turnkey contractor/developer handles land acquisition, project financing, permitting, engineering design, equipment procurement, construction, and startup commissioning. The Owner simply pays the agreed price upon final completion and "turns the key" to begin operating a fully equipped facility.

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The Four Core Contract Pricing Structures and Risk Allocation

1. Lump-Sum (Fixed-Price / Stipulated-Sum) Contract

In a Lump-Sum Contract, the contractor agrees to furnish all labor, materials, equipment, supervision, overhead, and profit required to complete the entire scope of work shown in the Contract Documents for one fixed total dollar price.

• When Used: Requires well-defined, 100% complete plans and specifications at the time of bidding so the estimator can perform an accurate quantity takeoff.
• Risk Allocation: Places the highest cost risk on the Contractor and the lowest cost risk on the Owner. If the contractor builds the project more efficiently than estimated, the contractor keeps 100% of the cost savings as additional profit. Conversely, if labor rates, material prices, or crew hours exceed the estimate, the contractor absorbs 100% of the cost overrun (unless the Owner orders a scope change or a compensable Differing Site Condition occurs).

2. Unit-Price Contract

In a Unit-Price Contract, the bidder quotes a fixed dollar price per installed unit of measurement (which includes direct cost, overhead, and profit per unit—such as $140 per cubic yard of mass rock excavation, $85 per linear foot of 8-inch PVC sewer main, or $110 per ton of hot-mix asphalt) based on estimated quantities provided by the Owner's engineer. Final payment is calculated by multiplying the actual field-measured quantities installed by the contract unit prices.

• When Used: Ideal for heavy civil, highway, earthwork, deep foundation piling, and municipal utility projects where the nature of the work is clear, but exact quantities cannot be determined until excavation is underway.
• Risk Allocation: Splits risk cleanly between the parties: the Owner bears the quantity risk (if 1,500 cubic yards of rock are encountered instead of the estimated 1,000 cubic yards, the Owner pays for 1,500 cubic yards), while the Contractor bears the unit-cost risk (if the contractor's crew costs $160/CY to excavate rock that was bid at $140/CY, the contractor loses $20/CY). Most unit-price contracts include a Variation in Estimated Quantities (VEQ) clause allowing either party to request an equitable unit-price adjustment if actual quantities vary by more than 15% to 25% above or below the estimated bid schedule quantities (protecting fixed mobilization/overhead recovery on major underruns and preventing windfalls on major overruns).

3. Cost-Plus (Cost-Reimbursable) Contracts

In a Cost-Plus Contract, the Owner reimburses the contractor for actual, documented, auditable direct project costs (field payroll, materials, subcontracts, equipment rentals) plus an agreed Fee to cover the contractor's home-office general and administrative (G&A) overhead and profit. Cost-plus contracts require open-book accounting and a strict contractual list separating Reimbursable Job Costs from Non-Reimbursable Home-Office Costs. There are three primary Cost-Plus structures:

1. Cost Plus Percentage of Cost (CPPC): The Owner pays actual direct costs plus a fee calculated as a percentage (e.g., $15\%$) of those actual costs. CPPC places the highest financial risk on the Owner (and lowest on the contractor) because every dollar of waste, inefficiency, or material price inflation increases the contractor's dollar fee. Because it rewards overspending, CPPC is prohibited in federal government contracting.
2. Cost Plus Fixed Fee (CPFF): The Owner reimburses actual direct costs plus a predetermined, fixed dollar fee (e.g., actual reimbursable costs + $95,000 fixed fee). Because the contractor's fee remains fixed at $95,000 even if direct costs rise, the contractor has no financial incentive to inflate job costs (and has an incentive to finish quickly to earn the fixed fee in fewer months).
3. Cost Plus with Guaranteed Maximum Price (Cost-Plus GMP): The Owner reimburses actual direct costs plus the contractor's fee only up to a contractual ceiling known as the Guaranteed Maximum Price (GMP). If total actual costs plus fee exceed the GMP, the contractor must absorb 100% of the overrun above the GMP out of its own pocket. If total actual costs plus fee come in below the GMP, the resulting cost savings (underrun) either revert 100% to the Owner or are divided between the Owner and Contractor according to a Shared-Savings (Incentive) Clause (such as 70% to Owner / 30% to Contractor).

$$\text{Contractor Payout under Shared-Savings GMP} = \begin{cases} \text{Actual Cost} + \text{Base Fee} + s_c \times (\text{GMP} - (\text{Actual Cost} + \text{Base Fee})) & \text{if } (\text{Actual Cost} + \text{Base Fee}) < \text{GMP} \\ \text{GMP} & \text{if } (\text{Actual Cost} + \text{Base Fee}) \ge \text{GMP} \end{cases}$$

4. Time and Materials (T&M) Contract

A Time and Materials (T&M) Contract compensates the contractor based on fixed composite hourly labor billing rates (which already include base wages, payroll taxes, workers' compensation, overhead, and profit per hour) plus actual material and equipment invoices plus an agreed markup percentage. T&M is widely used for emergency repairs, small unquantifiable remodeling tasks, or force-account change orders. Because an open-ended T&M contract exposes the Owner to productivity risk, Owners typically require daily signed field time tickets and a Not-to-Exceed (NTE) cap.

Worked Numeric Example: Cost-Plus GMP with a 75% / 25% Shared-Savings Clause

Suppose a Tennessee CM at Risk signs a Cost-Plus Fixed Fee contract with a Guaranteed Maximum Price (GMP) to construct a medical clinic in Chattanooga under the following terms:

• Target Direct Cost Estimate: $2,000,000

• Contractor's Fixed Fee: $180,000

• Guaranteed Maximum Price (GMP): $\text{\textdollar}2,000,000 + \text{\textdollar}180,000 = \text{\textdollar}2,180,000$

• Shared-Savings Clause: Any savings below the $2,180,000 GMP are split 75% to the Owner and 25% to the Contractor.

• Scenario A — Cost Underrun (Actual Direct Costs = $1,860,000):

  1. Total Cost + Fixed Fee before savings split: $\text{\textdollar}1,860,000 + \text{\textdollar}180,000 = \text{\textdollar}2,040,000$
  2. Total Savings Below GMP: $\text{\textdollar}2,180,000 - \text{\textdollar}2,040,000 = \text{\textdollar}140,000$
  3. Contractor's 25% Incentive Share of Savings: $0.25 \times \text{\textdollar}140,000 = \text{\textdollar}35,000$
  4. Total Contractor Fee Earned: $\text{\textdollar}180,000 + \text{\textdollar}35,000 = \mathbf{\text{\textdollar}215,000}$
  5. Total Amount Paid by Owner: $\text{\textdollar}1,860,000 + \text{\textdollar}215,000 = \mathbf{\text{\textdollar}2,075,000}$ (saving the Owner $0.75 \times \text{\textdollar}140,000 = \text{\textdollar}105,000$ below the GMP).

• Scenario B — Cost Overrun (Actual Direct Costs = $2,110,000):

  1. Total Uncapped Cost + Fixed Fee: $\text{\textdollar}2,110,000 + \text{\textdollar}180,000 = \text{\textdollar}2,290,000$
  2. Because $2,290,000 exceeds the $2,180,000 GMP by $110,000, the Owner pays exactly the $2,180,000 GMP ceiling, and the contractor absorbs the $110,000 overrun, reducing the contractor's net realized fee to $\text{\textdollar}180,000 - \text{\textdollar}110,000 = \mathbf{\text{\textdollar}70,000}$.

Delivery comparisons describe typical arrangements. Design-bid-build can use separately designed bid packages; design-build does not guarantee the absence of disputes. A GMP’s design-completion percentage, variation-in-quantity trigger, shared-savings split, and reimbursable costs come from the particular agreement. Turnkey/EPC scope does not automatically include land acquisition or financing unless contracted.