SUMMARY

Construction Strategies and Techniques for Planned Bridge Replacements in Complex Scenarios

State departments of transportation (DOTs) undertake numerous bridge replacements annually. Specific replacements present unique challenges among these projects due to location restrictions, mobility implications, design characteristics, and environmental constraints. In these cases, DOTs must balance maintaining mobility, ensuring work zone safety, achieving construction quality, navigating geometric constraints, managing material availability, and mitigating environmental impacts while adhering to budget and schedule constraints.

DOTs employ various construction strategies and techniques for complex bridge replacement projects, carefully considering multiple factors in their decision-making processes. Navigating these complex scenarios is challenging, and the available strategies and techniques continually evolve. Given this dynamic environment, it is essential to document current practices, available guidance documents, and the experience gained by the DOTs. This synthesis report was prepared to help DOTs address future bridge replacement needs and overcome challenges associated with complex bridge replacement scenarios.

This synthesis documents the practices and decision-making used by the DOTs for planned bridge replacements in complex scenarios. For this synthesis, complex scenario refers to bridge replacements on critical arteries or remote roadways necessitating complex and, in some cases, costly strategies and construction techniques. Information gathered includes:

• Construction strategies and techniques DOTs use to construct bridge replacements;
• Factors and constraints DOTs consider when choosing the appropriate bridge replacement construction strategies and techniques; and
• Written policies, rubrics, guidelines, metrics, and tools DOTs use for bridge replacement decision-making in complex scenarios.

Information for the synthesis was gathered through a literature review, a survey of DOTs, and follow-up interviews with selected DOTs to develop case examples.

The literature review revealed that, while resources detailing general DOT bridge replacement guidelines and documents describing construction, procurement, and project delivery techniques are available, there is a notable gap in specific documentation that addresses complex bridge replacement scenarios and the associated decision-making processes employed by DOTs. The review focused on relevant FHWA documents and those shared by DOTs in response to a survey question regarding existing guidance for complex bridge replacement projects.

The survey questionnaire was developed and distributed to the voting members of the AASHTO Committee on Bridges and Structures in all 52 DOTs (50 state DOTs and

those of Puerto Rico and Washington, DC). Of those, 47 DOTs participated in the survey (a 90% response rate).

Detailed case examples from six DOTs—California DOT, Colorado DOT, Massachusetts DOT, Texas DOT, Washington State DOT, and Wisconsin DOT—were created to provide deeper insights into the strategies, decision-making processes, and project delivery methods (PDMs) employed for complex bridge replacements. These DOT examples were identified based on survey responses and literature review findings, focusing on DOTs that reported using unique strategies or methods, had specific guidelines or experience with various replacement strategies or PDMs, and had distinctive approaches to gaining stakeholder buy-in for complex bridge replacement projects.

The survey consisted of 17 questions addressing various aspects of complex bridge replacement projects, including construction strategies and techniques, project delivery and procurement methods, decision-making factors, strategies for gaining stakeholder buy-in, and any policy changes. The results revealed that DOTs employ a diverse range of construction strategies. Staged construction was used by all 47 DOTs, while constructing new bridges off the existing alignment and full detour closures were used by 46 of the 47 DOTs (98%). Accelerated bridge construction (ABC) techniques, aimed at minimizing disruption, were adopted by 41 of the 47 DOTs (87%) and temporary bridges by 43 of the 47 DOTs (91%).

However, 7 of the 47 DOTs (15%) reported being unable to use certain strategies due to state contracting or procurement restrictions. These restrictions affected options like bundling, indefinite delivery and indefinite quantity (ID/IQ), design-build (D-B), and construction manager/general contractor (CM/GC) methods, as well as innovative techniques like ABC due to contractor availability or other limitations. The most commonly used PDM was design-bid-build (D-B-B), employed by 46 of the 47 DOTs (98%), followed by D-B (39 of 47 DOTs, 83%), CM/GC (24 of 47 DOTs, 51%), and public-private partnerships (19 of 47 DOTs, 40%).

The survey also identified key factors influencing strategy selection: site/location, bridge/design, construction management, and cost. All 47 respondent DOTs considered average annual daily traffic (AADT) and detour distance significant site-related factors, with site characteristics and roadway safety being primary considerations for 46 and 45 DOTs, respectively. Environmental impacts and right-of-way procurement were important for 44 DOTs (94%), while disaster evacuation routes influenced 25 DOTs (53%). Critical bridge/design factors included proposed bridge geometry (46 of 47 DOTs, 98%), structure type (45 of 47 DOTs, 96%), existing bridge geometry (42 of 47 DOTs, 89%), and bridge size (41 of 47 DOTs, 87%).

Construction management considerations such as contract period strategy, including working days, calendar days, and incentive/disincentive systems (A+B), influenced decision-making for 39 of the 47 DOTs (83%). Weather conditions and project duration were also influential in strategy selection for 38 of the 47 DOTs (81%), with PDMs factored in by 36 of 47 DOTs (77%). Additionally, demolition constraints and construction techniques were considered for 34 and 33 DOTs, respectively. Cost considerations, particularly direct costs, were the most frequently considered by 42 DOTs (89%), with funding constraints noted by 37 DOTs (79%) and asset life-cycle costs by 35 DOTs (74%).

Frequent in-depth communication was the most commonly used strategy employed by 40 DOTs (85%) to gain stakeholder buy-in. Providing a project website was another approach used by 39 DOTs (83%). Discussing the benefits of the strategy was reported to help clarify the project’s value for 36 of the DOTs (77%), with 10 DOTs also using white

papers for detailed project information. Negotiating property improvements was another noted strategy.

Based on past experiences, DOTs reported updates in policies and practices, including the incorporation of incentive and disincentive clauses (33 of 44 respondent DOTs, 75%), improved community communication (32 of 44 DOTs, 73%), project design (31 of 44 DOTs, 70%), scheduling and management (30 of 44 DOTs, 68%), and the use of innovative materials or techniques (28 of 44 DOTs, 64%). The survey responses emphasized the importance of flexible and adaptive approaches. They highlighted the need for continuous improvement in policies and practices to address evolving challenges in complex bridge replacement projects.

Six DOTs’ case study examples (California DOT, Colorado DOT, Massachusetts DOT, Texas DOT, Washington State DOT, and Wisconsin DOT) illustrate various strategies, decision-making processes, and PDMs for complex bridge replacement scenarios.

California DOT (Caltrans) utilizes an adaptable project delivery selection process guided by an Alternative Procurement Guide. It focuses on collaborative decision-making and early stakeholder communication and notes the importance of legislative support for implementing innovative techniques. Colorado DOT conducts comprehensive evaluations using its Structure Selection Report and supports effective project management through its Alternative Delivery Program. Critical elements for complex bridge replacement projects include continuous stakeholder communication and innovative financial planning for sustainability and efficiency.

Massachusetts DOT (MassDOT) employs a systematic project review process and decision flowchart, prioritizing traffic and environmental considerations and using techniques like bridge bundling and ABC. Continuous improvement and industry engagement are noted for refining strategies. Texas DOT (TxDOT) focuses on flexibility and collaboration in strategy selection, guided by the Texas Bridge Project Development Manual, and leverages ABC techniques while maintaining transparent communication.

Washington State DOT (WSDOT) adopts a dynamic strategy selection approach, maintains comprehensive guidelines updated through stakeholder feedback, and emphasizes quality control and pilot projects for innovation. Wisconsin DOT (WisDOT) involves collaborative decision-making, integrates ABC methods to expedite construction and minimize disruption, and notes the importance of stakeholder engagement and communication through pilot projects.

The synthesis findings highlight an opportunity to investigate further the decision-making processes and strategies used in complex bridge replacements, explicitly focusing on alternative contracting methods (ACMs) and PDMs. Future potential research could focus on the long-term benefits and challenges of implementing methods like progressive design-build (PDB) and CM/GC compared with traditional D-B-B methods, particularly regarding their impact on project timelines, costs, and quality. Additionally, it could be helpful to study contractor concerns to adopt innovative techniques such as ABC and prefabricated components and to explore strategies to incentivize their use, including financial incentives, training programs, and presentation of successful case studies.

Further areas for future potential research include evaluating the effectiveness of different communication strategies used by the DOTs to gain stakeholder buy-in and examining how digital communication tools can enhance stakeholder engagement compared to traditional methods. Investigating how decision-making processes consider asset life-cycle and

indirect costs, developing national guidance documents for strategy selection and project management, and understanding risk management approaches for complex bridge replacement projects are also potential subject areas. Moreover, the research could explore how DOTs manage D-B projects, the details of contractor involvement in the design phase, and effective communication strategies for obtaining contractor feedback. Experience gained from the DOTs using ACMs and current public engagement and communication practices are additional areas for future exploration.