Abstract

Material costs, labor shortages and tight schedules have caused architects, engineers and contractors to explore alternate project delivery methods. Overlapping design and build operations in varying degrees has the potential to reduce construction time and production costs. Integrated project delivery and multi-party agreements allow project teams to work in collaborative ways not envisioned by traditional design-bid-build. Lean construction and fast tracking strive the improve quality, reduce waste and avoid conflicts. Building information modeling allows for better planning, while sustainable practices focus on reducing life cycle costs. Research concludes that the design-build method is an improvement over traditional methods of construction.

Keywords: design-build, joint venture, integrated project delivery, lean construction, fast tracking, building information modeling, sustainability

An Investigation of the Design-Build Project Delivery Method

by Jeffrey C Kadlowec, Registered Architect

Rising material cost, labor shortages and tight projects schedules are forcing designers and builders to deviate from the traditional Design-Bid-Build (DBB) method into alternative delivery models [1]. Owners are seeing the benefits from collaboration through joint-ventures, improving project quality and performance with reduction in total cost. Bringing contractors and subcontractors together early with architects and engineers can significantly reduce the inherent risks that exist in the traditional process. Continued dissatisfaction with DBB has led owners to take interested in Design-Build (DB), which has gain a major and growing presence in the market [2].

Design-build provides a single point of contract, minimizing risks for the owner and compressing the delivery schedule. Whether a builder-led, designer-led or joint venture, this concept of the “master builder” is one of the oldest form of construction, dating back over four thousand years. The traditional method of procurement—in contrast—came into practice only 150 years ago [3]. The Design-Build Institute of America (DBIA) holds that a single contract is what differentiates it from the DBB method.

The “design-builders” have typically been a general contractor that employed architects and engineers directly or as a subcontractor. Until 1979, the American Institute of Architects (AIA) prohibited members from providing construction services. But in 2003, the AIA endorsed “The Architect’s Guide to Design-Build Services,” to assist its members in acting as design-build contractors [3]. The diagrams in Figure 1 illustrate how contractor-led and architect-led projects are commonly structured with the term integrated project delivery (IPD) used to describe joint ventures as a collaboration between builders and designers.

Single-source contracting for design and construction services offer many advantages—collaboration through mutual trust and respect with shared risk and reward, early involvement of key participants providing knowledge of cost and scheduling, and the elimination of waste and duplication through open communication and common goals [4]. The integrated project delivery (IDP) method of construction seeks to efficiently involve all participants throughout all phases of design, fabrication and erection to increase productivity, improve quality, reduce waste, avoid scheduling delays, and minimize conflicts between owners, contractors and architects [5]. A multi-party agreement (MPA) can be executed to create a formal organization for any project. Outlining the roles, relationships and contributions of all team members ensures overall success by establishing trust through transparent disclosure. Job Order Contracting (JOC) is one form of IPD—resulting in over 90% of projects that are on-time and in-budget—is specific to repairs, renovations and minor new construction [5]. Lean Project Management (LPM) utilizes operational systems based on lean principles: optimization of the whole, removal of waste, focus on process & flow, generation of value, and continuous improvement [6].

New models and practices in the construction industry have had a substantial impact on the success of projects. Collaborative working environments and lean delivery bring together key parties aligning interests through mutual trust and shared risk-reward [7]. Joint design, control and management by early involvement of architects, engineers and contractors with open communication and cooperation differs from the traditional DBB approach. Focus is on working collaboration for production, not a series of contracts and transactions. Design of the product and planning of the process are concurrent activities performed at the proper moment, not as soon as possible. Major decisions are made through unanimous agreement, not by individuals working in alone. The entire process is a continuous effort throughout the life of the project, not by a series of sporadic decisions [7]. This results in mutually beneficial, non-adversarial relationships through completion of the project and a likelihood towards future working collaborations.

The construction industry has recently seen unprecedented growth with large-scale and complex projects fueled by the urbanization of major cities. Construction accounts for 6-10% of the GDP in developed countries and 3-6% in developing countries [8]. Design-build has emerged to replace the traditional design-bid-build process, particularly in the public sector. Creating a harmonious work environment with better communication is key to the integration of project team members.

Much as my years of professional experience in architecture led to the conclusion that engineering coordination is key to project success, the results of a recent study [8] found effective design and construction (DC) coordination to be the critical factor affecting time, cost and quality in regards to project performance. Accordingly, proper coordination is necessary in the following areas: 1) Scheduling & Planning; project briefs, control of tasks & activities, methods of execution, 2) Human Resources; estimation of workforce, proper placement of staff, experience & expertise of project managers, 3) Documentation & Records; accurate drawings & calculations, verbal & written correspondence, quality & detail of execution plans, 4) Contract Implementation; understandable agreements, ongoing communication, specification and technical information, 5) Value Engineering & Quality Assurance; analysis of building features, lowered life cycle cost, performance & reliability, 6) Technical; project performance, identify issues, effective support, 7) Design; avoid changes & variations, frequent feedback, crucial directives, 8) Management; clear job duties, communication by project manager (PM) staff, proper record keeping, and 9) External Factors; permitting, progress evaluation, inspection agencies [8].

Project delivery experienced a major transformative shift in the last decade of the twentieth century. The rise of new tools, techniques and technologies brought the industry from a general understanding of design philosophies and construction practices, into a new era of sustainable principles [9]. Over the past thirty years, the lean construction, sustainability and building information modeling (BIM) have evolved construction—improving the design, planning and management processes while reducing the negative impacts on society, the economy and the environment.

Lean construction (LC) emerged by adopting principles of lean production in response to low productivity, unreliable planning, unfair division of risks / rewards, mistrust between project participants, dominance of low-bid criteria in contractor selection, and lack of involvement of contractors in design and planning [9]. The critical path method (CPM) used in planning and control of traditional DBB construction, limited master schedules to milestone levels of detail and decision making within each construction phase. Analysis of the CPM broke down tasking into a simplified “should,” “can / will,” & “did” approach; while sustainability, LC and BIM aim to synergize project delivery by developing context-specific target indicators, incorporating operations to provide continuous performance data, and ensure benefits throughout all lifecycle phases (9).

Fast-tracking has been extensively applied by the construction industry to meet growing demands and production time constraints [10]. However, there are inherent risks involved in overlapping design and construction as illustrated in Figure 2. Careful consideration should be taken since these risks could jeopardize the entire project due to costly redesign and rework, though well-designed projects could benefit from this accelerated strategy with proper managerial oversight. It is difficult to determine the optimal amount of overlap between design and construction due to varying levels of uncertainty. Owners continue to pressure for faster project delivery without enough consideration to the impact of time and cost risks [10].

As the construction industry continues to explore ways to reduce time schedules, the potential for increases in total cost has project managers developing new methods for analyzing the trade-offs. The time and cost optimized decision support model for fast-tracking construction begins with an extensive literature review. Scheduling and cost estimating models are then created and optimized using genetic algorithms. This new optimization module is then applied to case studies to measure its effectiveness [11]. By identifying specific areas for engineering and stages of construction phases, early planning becomes a tool to help owners in decision making.

Assessing the efficiency of construction companies can be determined bases on short-term and long-term performance. Developing and implementing strategies to solve actual problems and improve quality while reducing costs is key to their success. Project managers must strive for equilibrium between higher efficiency and lower costs in the shortest time while focusing on completion of design requirements [12]. Project administrators should carefully select skilled and knowledgeable leaders, create a friendly work environment, hold coordination meetings, and provide the necessary tools and equipment—while focusing on the project first, quality second and costs third. Master planning should incorporate the size of the labor force, take advantage of overtime, divide workload amongst subcontractors, expect change orders and market variations and take advantage of technological developments [12].

Accurate documentation is essential in the design and execution of a construction project. Various stakeholders require a proper framework is required for information in the form of design drawings, product specifications, cost estimates and contract documents. The amount of documents necessary to construct a project grows with its size and complexity. This large collection of data must be managed through an effect framework. Seamless flow and tracking of digital information and accessibility to these documents is key to the success of fast-track projects [13]. Identifying problem areas in document approval, document storage & placement, document tracking, searching & finding information, and sharing documents will optimize that process.

The pressure of budget constraints—particularly on government funded projects—continues to stress the “do more with less” mantra [14]. Before 1996, federal regulations prevented using most alternate delivery methods except DBB. When Congress passed the Clinger-Cohen Act, guidelines were established to determine if DB was appropriate for public projects. The Naval Facilities Engineering Command (NAVFAC), leading along with other organizations, began comparing similar DBB and DB projects in military construction (MILCON). Records were imported from financial information system (FIS) databases, including management of funding, project accounting and construction contracts. Using standard descriptive statistics, a single factor analysis of variance was used in the comparisons. Escalation tables from the office of management and budget (OMB) adjust for inflation. The area cost factor (ACF) index developed by the Department of Defense (DoD) identified a midpoint of construction based on historical averages over specific locations to determine “the cost of construction material, labor and equipment accounting for “weather, climate, seismic conditions, mobilization, overhead and profit, labor availability, and labor productivity. [14]. The results concluded—though without statistical significance—that the DB delivery method is superior to traditional DBB practices in building projects.

Figures

Figure 1: Models of contractor-led and architect-led design/build [3].
 

Figure 2: Traditional Design-Bid-Build versus Architect-Led Design Build schedules [3].

References

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