CHAPTER 5

Summary of Findings

This synthesis documents the practices and decision-making that state DOTs use for planned bridge replacements in complex scenarios. For this scope, complex scenario refers to bridge replacements on critical arteries or remote roadways necessitating complex and, in some cases, costly strategies and construction techniques. In these complex scenarios, the resulting techniques for replacing the bridge need to balance the goals of maintaining mobility, work zone safety, construction quality, geometric constraints, material availability, and environmental impacts, along with budgetary and schedule constraints.

This chapter summarizes the key findings from the literature review, a survey sent to 52 DOTs (50 state DOTs and those of Puerto Rico and Washington, DC) with 47 DOTs’ responses (a 90% response rate), and case example interviews conducted with six DOTs for this project. It also presents suggestions for future research.

Key Findings

Varied processes and techniques are used by DOTs for complex bridge replacement scenarios. Despite the diversity of approaches, there is a gap in standardized processes adaptable across various scenarios. DOTs incorporate distinct approaches informed by existing frameworks and innovative practices such as bridge bundling, ABC, and alternative PDMs. The integration of public and stakeholder input, along with the alignment of environmental, social, and economic considerations, is emphasized to ensure strategies are technically feasible, cost-effective, and socially and environmentally responsible.

Key findings from the survey reveal diverse applications of construction strategies, with staged construction and constructing new bridges off the existing alignment being the most frequently used techniques. Due to state contracting or procurement restrictions, 7 out of 47 DOTs (15%) were unable to utilize certain strategies such as bundling, ID/IQ, D-B, and CM/GC methods, as well as innovative techniques like ABC. The survey highlights varied PDMs utilized for complex bridge replacement scenarios, with D-B-B being the most common, followed by D-B and CM/GC. Factors influencing strategy selection include site-specific elements, bridge design considerations, construction management issues, and cost. Common strategies for gaining stakeholder buy-in include frequent communication and providing project websites. The findings underscore the use of flexible, adaptive approaches and continuous improvement in policies and practices.

Case study examples from six DOTs (California, Colorado, Massachusetts, Texas, Washington State, and Wisconsin) illustrated strategies, decision-making, and project delivery processes for complex bridge replacement scenarios.

• California: Caltrans employs an adaptable project delivery selection process using an Alternative Procurement Guide and emphasizes collaborative decision-making, early communication, and legislative support to use innovative techniques. Ongoing adaptation and feedback mechanisms are noted to be critical for refining strategies.
• Colorado: CDOT uses comprehensive evaluations through the Structure Selection Report and supports effective project management through its Alternative Delivery Program. Continuous stakeholder communication and innovative financial planning are noted to be critical for sustainability and efficiency.
• Massachusetts: MassDOT utilizes a systematic project review process and decision flowchart, prioritizes traffic and environmental considerations, and employs innovative techniques like bridge bundling and slide-in bridge construction. Continuous improvement and industry engagement are noted to be key to refining strategies.
• Texas: TxDOT emphasizes flexibility and collaboration for strategy selection, uses the state’s Bridge Project Development Manual for guidance, leverages ABC techniques in specific areas, and focuses on transparent communication.
• Washington State: WSDOT adopts a dynamic strategy selection approach, maintains comprehensive guidelines updated through stakeholder feedback, and emphasizes quality control and pilot projects for innovation to ensure effective strategies.
• Wisconsin: WisDOT involves collaborative decision-making for strategy selection, integrates ABC methods to expedite construction and minimize disruption, and highlights the importance of stakeholder engagement and communication through pilot projects.

Opportunities for Future Research

The synthesis findings reveal that while DOTs use specific strategies for complex bridge replacement scenarios, there is an opportunity to investigate aspects of the decision-making process and utilized strategies (e.g., ACMs and PDMs) for complex bridge replacement scenarios, to streamline the decision-making process and develop guidance. Suggestions for future research include the following:

• Investigation of the long-term benefits and challenges of implementing ACMs such as PDB and CM/GC compared to traditional D-B-B methods. Assessment of how these methods influence project timelines, costs, and quality.
• Studying contractor concerns with adopting innovative construction techniques. Exploring strategies to incentivize contractors to use innovative techniques, including financial incentives, training programs, and presentation of successful case studies.
• Evaluation of the effectiveness of different communication strategies used by DOTs to gain stakeholder buy-in for complex bridge replacement projects.
• Research on how digital communication tools (e.g., project websites, social media) can engage stakeholders better than traditional methods (e.g., public meetings, printed materials).
• Research on how complex bridge replacement decision-making considers asset life-cycle and indirect costs.
• Development of national guidance documents for strategy selection, project management, contracting methods, and PDMs for complex bridge replacement scenarios.
• Research into how agencies approach risk management programmatically with complex bridge replacement projects, which could consider complex bridge replacements in complex scenarios and simpler bridge replacements in complex scenarios.
• Investigation into how DOTs manage D-B projects, details on the process, and information on who participates in the decision-making.
• Specific examples of complex bridge replacements with details on how they were built, including the decision-making process, design and construction, experience gained, pros/cons of alternatives, and challenges and issues.

• Strategies to train the workforce to use alternative project delivery and construction techniques.
• Details and practice on Contractor Input During Design, which involves prequalifying contractors and collaborating with them during the design phase, as well as case studies of its use.
• Effective communication examples for DOTs to get feedback from contractors during the design phase.
• Investigation of how states consider indirect costs in complex bridge replacement decision-making, resulting in a guide.
• Experience gained by DOTs for alternative contracting.
• Current practice on how DOTs communicate their project information. How do the DOTs communicate this information in public engagement using white papers or project websites? What kind of engagement for stakeholders occurs? What is included in this communication? How do the state DOTs decide what this engagement includes?