CHAPTER 3

State of the Practice

This chapter documents the current state of the practice and decision-making used by DOTs for planned bridge replacements in complex scenarios by synthesizing the findings from the survey. The survey questionnaire was 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). The majority of AASHTO COBS voting members are state bridge engineers. Of the 52 DOTs, 47 participated in the survey (a 90% response rate).

The survey included 17 questions on construction strategies and techniques that DOTs use to construct bridge replacements, factors and constraints DOTs consider when choosing the appropriate bridge replacement construction strategies and techniques, and what (if any) written policies, rubrics, guidelines, metrics, and tools the DOTs use for bridge replacement decision-making in complex scenarios. The questions were formatted as multiple-choice, featuring either single or multiple selections, except for the last question, for which DOTs were asked to provide files or links for guidance documents. Some questions had multiple parts, employing survey logic to reveal additional questions based on prior responses. Two questions were structured as matrices, offering checkboxes for various relevant factors. Where necessary, text boxes were included to gather further information or explanations. These text boxes appeared in two scenarios: when an “other” option was available and when an explanation was asked for a particular choice.

The survey questions were organized into the following categories:

• Contact Information: The first two questions gathered basic information on the respondent’s DOT, including name, email, and phone number. These answers were used to identify each DOT’s responses and communicate with the respondents when necessary.
• Construction Strategies and Techniques: Two questions focused on the construction strategies and techniques the DOT used or considered for complex bridge replacement scenarios, and a third question asked whether there were replacement construction strategies and techniques not considered or implemented because of restrictions.
• Project Delivery and Procurement Methods: One question addressed the DOT’s project delivery and procurement strategies or techniques that the DOT used.
• Factors Considered for Decision-Making: Four questions explored factors related to site or location, bridge design, construction management, and cost to understand the major influences on decision-making for complex bridge replacement scenarios.
• Strategies for Gaining Buy-In: Three questions examined the existence and use of certain strategies to gain buy-in for complex bridge replacement projects.
• Policies for Decision-Making: Four questions inquired about policies and documents, the DOT’s interest in participating in a case study, and any changes to policies or guidelines based on experience.

The information is presented in several formats, including both tables and graphs, as appropriate. A copy of the electronically distributed survey questions is provided in Appendix A, and individual survey responses are provided in Appendix B. The percentage of DOT responses and counts are reported in the discussion. It is important to note that not all 47 DOTs answered every question. Consequently, the survey results represent the percentage of responses for each specific question. When multiple selections were possible for a question, this was indicated in the graph.

Construction Strategies and Techniques

After the survey obtained contact information, the first question gathered information related to DOT practice and focused on construction strategies and techniques for handling complex bridge replacement scenarios (Figure 3-1). The responses indicated a diverse application of strategies by DOTs. Staged construction emerged as the most frequently used technique, closely followed by constructing a new bridge off the existing alignment, shifting traffic, closure, and full detour. Temporary bridges involving diversions or runarounds are also frequently used, while 41 respondents reported using ABC techniques. None of the respondents selected the option indicating no use of any listed techniques, underscoring the application of varied methods in managing complex bridge replacement scenarios. Massachusetts DOT added bridge slides and New York State DOT added bridge slides and SPMTs to the list. It should be noted that MassDOT and NYSDOT added specific ABC techniques under “other” while other DOTs categorized these specific techniques under ABC.

The question on the DOT’s experience with the most typical construction techniques revealed that most DOTs utilize various techniques. Staged construction is prevalent, with all 47 DOTs indicating they have used it and would consider using it again (Figure 3-2). The strategies of closure, full detour, and construction of a new bridge off the existing alignment and shifting traffic are also commonly used, with 46 of the 47 responses (98%) confirming their use and potential future application. ABC techniques that minimize disruption were utilized by 42 of the 47 DOTs (89%), which also reported they would consider their future use. Another 2 DOTs noted that they considered ABC but could not use it due to restrictions. Temporary bridges involving diversions or runarounds were utilized by 43 of the 47 DOTs (91%), with 1 DOT unable

to use this strategy due to regulations. The “Other” category showed that 39 of the 47 DOTs (83%) did not consider different techniques. At the same time, 7 of the 47 DOTs (15%) tried alternative techniques and would consider their future use, and 1 DOT was restricted from using a considered alternative. None of the DOTs responded that they had used a technique but had no future plans to use to use it again due to the experience. This data highlights the widespread adoption of various construction techniques, with very few DOTs facing restrictions that prevent usage.

In the survey, when asked whether there were certain bridge replacement construction strategies and techniques for complex scenarios that the DOT has not considered or implemented due to state contracting and procurement restrictions, 7 out of 47 DOTs (15%) answered affirmatively, indicating that these restrictions are indeed preventing the use of these strategies and techniques.

When asked which techniques DOTs could not utilize due to restrictions, the responses showed limitations for various DOTs in employing specific bridge construction methods. Colorado DOT is restricted from constructing multiple bridges in a bundle using ID/IQ delivery methods. The Iowa DOT cannot use ACMs such as D-B and CM/GC. Maine DOT notes that its ability to use ABC is minimal based on its contractor’s ability to staff a project with a compressed schedule. Similarly, Mississippi DOT is limited to using only the D-B method from alternative delivery methods. New Jersey DOT is in the transitional phase of implementing D-B project delivery. North Dakota DOT could not use the Bridge Slide technique due to restrictions. For specific DOTs, regulatory and practical constraints influence the ability to use a particular construction strategy.

Project Delivery and Procurement Methods

The survey data indicates the prevalence of different project delivery and procurement methods used by the DOTs. The D-B-B method is the most commonly used, with 46 of the 47 DOTs (98%) employing this traditional approach. D-B, which integrates both the design and construction phases by a contractor, is also widely adopted by 39 of the 47 DOTs (83%). The CM/GC method is used by 24 of the 47 DOTs (51%). CM/GC project delivery is an integrated team approach for planning, designing, and constructing a highway project. The DOT selects

the designer, the construction manager (CM), and the independent cost estimator (ICE) for this method. The CM is usually chosen based on qualifications or a best-value approach. Early collaboration with the CM during the design phase helps establish design priorities, foster innovation, provide pricing for design alternatives, and develop strategies to manage potential construction risks. Besides contributing during preconstruction, the CM submits a guaranteed maximum price for a specific work package or the entire project. The ICE’s central role is to ensure the fairness and reasonableness of the CM’s construction costs by providing checks and balances during the price negotiation process (D’Angelo et al. 2019). Public-private partnerships, which involve collaboration between public entities and private companies, are utilized by 19 of the 47 DOTs (40%) (Figure 3-3). P3 involves a contractual agreement between a public agency and a private entity, which may include a consortium of multiple firms, to deliver a transportation project. The extent of private sector involvement in the design, construction, financing, operation, and maintenance of a transportation asset is determined by the public agency’s priorities regarding cash outlay, the timing of financial commitments, performance requirements, risk allocation in the short and long term, and available resources (D’Angelo et al. 2019).

Various state DOTs are exploring and implementing different procurement and delivery techniques, as responses indicate. According to the responses DOTs provided for the “Other” option, Alaska DOT is considering adopting progressive design-build. Arkansas, California, Kentucky, Michigan, Ohio, and Washington State DOTs currently utilize PDB. Florida DOT employs a phased D-B approach and has had limited use of CM/GC so far. Idaho DOT is focusing on early procurement strategies to enhance project delivery. Illinois has recently passed legislation allowing the use of D-B and CM/GC methods. Although no projects have commenced under these methods yet, they are expected to in the future. Maine DOT uses a unique method called Contractor Input During Design, which involves prequalifying contractors and collaborating with them during the design phase to address constructability issues.

Factors Considered for Decision-Making

The survey on site- or location-related factors that influence DOTs’ strategy selections for complex bridge replacements reveals significant insights (Figure 3-4). All respondent DOTs (47) indicated that average annual daily traffic (AADT), including specific considerations like percentage of truck traffic and pedestrian impact, as well as detour out-of-distance travel,

are crucial factors in decision-making. Close behind, 46 of the 47 (98%) DOTs consider site characteristics, which include hydraulic, geotechnical, and geometric requirements along with archaeology. Roadway safety is also a major factor for 45 of the 47 DOTs (96%). Environmental impacts, which encompass environmental justice, wildlife habitats, endangered species, water, and soil contamination, as well as right-of-way procurement (whether temporary or permanent), are considered by 44 of the 47 DOTs (94%). Disaster evacuation routes influence the decisions of 25 of the 47 DOTs (53%). Notably, no DOTs reported that these factors do not impact their decision-making process, highlighting the importance of these considerations in bridge replacement strategies.

Additionally, 5 of the 47 DOTs (11%) reported other unspecified factors influencing their strategy choices. According to the responses for the “Other” option, Alaska DOT highlighted the absence of available detours as a critical factor affecting its strategy decisions. In Colorado DOT, the presence of hazardous materials at the site dictates specific handling and safety protocols, affecting the choice of replacement methods. Both Georgia DOT and Iowa DOT emphasized the importance of input in their decision-making processes, with Georgia focusing on stakeholder input and Iowa on public input. Maryland DOT stressed that worker safety in the work zone is a concern that influences its bridge replacement strategies. These factors demonstrate the diverse considerations that DOTs must balance when planning and executing bridge replacement projects.

When DOTs consider bridge replacement construction strategies and techniques for complex scenarios, they consider various bridge or design-related factors (Figure 3-5). The factor considered by the most DOTs is the proposed bridge geometry or properties, with 46 of the 47 DOTs (98%). Close behind, 45 of the 47 DOTs (96%) consider the structure type, and 42 of the

47 DOTs (89%) factor in the existing bridge geometry or properties. The size of the bridge is also a significant consideration for 41 of the 47 DOTs (87%). Eight of the 47 DOTs (17%), reported that bridge-related factors do not impact their strategy selection. Additionally, Colorado DOT noted that haul routes and associated weight restrictions for precast elements also impact its strategy selection. None of the DOTs reported that these design or bridge-related factors do not impact their decisions at all.

In deciding bridge replacement construction strategies and techniques for complex scenarios, DOTs consider various construction management factors. The most highly considered factor is the contract period strategy, including considerations like working days, calendar days, and incentive/disincentive systems (A+B), which 39 of the 47 DOTs consider (83%). Construction season factors, such as weather conditions and project duration, are also crucial and are considered by 38 of the 47 DOTs (81%). PDMs, including D-B-B, D-B, CM/GC, and P3, are factored in by 36 of the 47 DOTs (77%) (Figure 3-6).

Additionally, 34 of the 47 DOTs (72%) consider demolition constraints and construction delivery methods when planning their strategies. Construction techniques and quality are important for 33 of the 47 DOTs (70%), while material type, availability, and quality considerations influence the decisions of 32 of the 47 DOTs (68%). Material delivery times are considered by 31 of the 47 DOTs (66%). Two DOTs reported that these factors do not impact their decision-making process, and none of the DOTs selected “Other” as a factor. This data highlights the diverse and complex array of management factors that influence how DOTs approach bridge replacement projects

Forty-two of the 47 DOTs (89%) reported that direct costs are the cost factor most frequently considered by DOTs when deciding on bridge replacement strategies and techniques (Figure 3-7). This indicates a primary concern with the immediate expenses associated with construction and material costs. “Funding constraints,” which refer to the limitations on available financial resources, also influence decisions, as noted by 37 of the 47 responses (79%). This suggests that budget availability is a determinant of how projects proceed.

Thirty-five of the 47 DOTs (74%) consider asset life-cycle costs, pointing to increasing awareness of the importance of evaluating long-term costs such as maintenance and operational expenses over the bridge’s lifetime. Twenty-nine of the 47 DOTs (62%) take indirect costs into account, including broader economic impacts like traffic disruptions and local business effects.

Financing ability, or the capacity to secure and use resources for specific strategies or techniques, impacts the decisions of 21 of the 47 DOTs (45%), underscoring the role of financial solvency and resource management in project planning.

Strategies for Gaining Buy-In

Forty of the 47 survey respondents (85%) indicated that the DOT implemented strategies that helped gain buy-in (e.g., from legislators or other stakeholders) for various bridge replacement strategies. As indicated by 40 of the 47 DOTs (85%), the most commonly used strategy is frequent, in-depth communication with stakeholders throughout the project development and construction phases. This indicates the importance of continuous engagement in building support and trust in project management (Figure 3-8).

Providing a project website was also commonly used, with 39 of the 47 DOTs (83%) using this approach to disseminate information and updates, thereby increasing transparency and accessibility of information to the public and stakeholders. Discussing the benefits of the strategy was another significant approach, cited by 36 of the 47 DOTs (77%), which likely helps clarify the project’s value and expected outcomes to gain public and stakeholder support.

Additionally, 10 of the 47 DOTs (21%) mentioned that providing a white paper that typically offers detailed information about the project scope, objectives, and methodologies helped gain buy-in. On the other hand, 3 of the 47 DOTs (6%) reported not having specific strategies to gain buy-in for bridge replacement projects, and 2 of the 47 (4%) noted using other unspecified strategies. Colorado DOT stated that negotiating property improvements is an alternative strategy utilized.

DOTs indicate a clear preference for frequent, in-depth communication with stakeholders (Figure 3-9). This strategy is the most widely used, with 23 of the 44 (52%) respondents indicating they use it “always” or “very often.” Providing a project website is also common, though not as universally adopted as direct communication, with responses varying from “always” to “never.” The least utilized strategy is issuing a project white paper, with 21 of the 44 respondent DOTs (48%) indicating they “rarely” or “never” use it. However, providing information about the project’s benefits is another widely adopted strategy, with 31 of the 44 DOTs (70%) using it

“always” or “very often.” These trends suggest that DOTs prioritize direct, clear communication and that they highlight their projects’ positive impacts to secure stakeholder support.

Policies for Decision-Making

In response to a survey question regarding the incorporation of changes into policy and/or practice from past projects with complex scenarios, DOTs reported several significant updates (Figure 3-10). The most shared areas of change include incentive and disincentive clauses (33 of 44 respondent DOTs, 75%), followed by communication with the community (32 of 44 DOTs, 73%) and design (31 of 44 DOTs, 70%), indicating an emphasis on enhancing project

performance, stakeholder engagement, and project planning. Project scheduling and management (30 of 44 DOTs, 68%) and the use of innovative materials or construction techniques (28 of 44 DOTs, 64%) also saw updates. Twenty-five of the 44 DOTs (57%) reported changes in contracting procedures and communication with design firms and contractors. Changes were also noted in selecting design firms or contractors and interagency communication. Additionally, 4 DOTs reported changes in other areas. The Alaska DOT mentioned the possible use of CM/GC methods for challenging projects, although this is just one factor in its decision-making process. The Florida DOT indicated that there are likely other areas where changes have been made. Meanwhile, the South Carolina and Wisconsin DOTs reported that no changes have been implemented in these areas. These updates reflect an effort among DOTs to refine their processes and adopt innovative practices to better manage complex bridge replacement projects.

Twenty-one of the 47 DOTs (45%) volunteered to participate in a case example illustrating the use of bridge replacement construction strategies and techniques for complex scenarios. When asked if the DOT has written policies, rubrics, guidelines, metrics, or tools for bridge replacement decision-making in complex scenarios, 17 of the 47 DOTs (36%) responded positively. Twelve DOTs shared DOT documents on their guidelines. Names and links for these resources are provided in Appendix B.

Survey Takeaways

This chapter documents the current state of the practice and decision-making used by DOTs for planned bridge replacements in complex scenarios. The findings are synthesized from a survey distributed to voting members of the AASHTO Committee on Bridges and Structures across 52 DOTs, including those of Puerto Rico and Washington, DC. With a response rate of 90% (47 of 52 DOTs), the survey provides a comprehensive overview of the strategies and considerations in use.

The survey comprised 17 questions on various aspects of complex bridge replacement projects. The questions aimed to gather insights on construction strategies and techniques, project delivery and procurement methods, factors considered for decision-making, strategies for gaining buy-in, and any changes in policies or guidelines.

The survey revealed diverse applications of construction strategies among DOTs. Staged construction emerged as one of the most frequently used techniques, with all 47 DOTs indicating they have used it and would consider using it again. Similarly, constructing a new bridge off the existing alignment and closure and full detour were employed by 46 of the 47 DOTs (98%). ABC techniques, which aim to minimize disruption, were used by 41 of the 47 DOTs (87%). Temporary bridges were also implemented by 43 of the 47 DOTs (91%).

Due to state contracting or procurement restrictions, 7 out of 47 DOTs (15%) could not use specific bridge replacement construction strategies and techniques for complex scenarios. These restrictions included certain PDM or contracting methodology options (bundling, ID/IQ, D-B, CM/GC) and construction techniques like ABC due to restrictions, contractor availability, or limitations. For specific DOTs, regulatory and practical constraints influence the ability to use a particular construction strategy.

Project delivery and procurement methods varied among the DOTs for complex bridge replacement scenarios. The D-B-B method was the most commonly used, employed by 46 of the 47 DOTs (98%). The D-B approach, which integrates both the design and construction phases by a contractor, was adopted by 39 of the 47 DOTs (83%). The construction manager/general contractor (CM/GC) method was used by 24 of the 47 DOTs (51%). P3s, which involve collaboration between public entities and private companies, were utilized by 19 of the 47 DOTs (40%).

However, several DOTs faced restrictions that limited their ability to use certain methods, such as ID/IQ, ACMs such as D-B and CM/GC, or ABC, due to contractor staffing constraints.

In the survey, DOTs were asked about the factors that influence strategy selections under four categories: site or location, bridge or design, construction management, and cost. Site or location-related factors played a role, with all 47 DOTs considering AADT and detour distance as significant. Site characteristics and roadway safety were also major considerations for 46 and 45 DOTs, respectively. Environmental impacts and right-of-way procurement influenced decision-making for 44 DOTs, while disaster evacuation routes influenced the decisions of 25 of the 47 DOTs (53%). The absence of available detours, the presence of hazardous materials at the site, and stakeholder and public input worker safety in the work zone were some other site-related factors that were noted by DOTs to be critical in decision-making. For bridge or design-related factors, factors such as the proposed bridge geometry (46 of 47 DOTs, 98%), structure type (45 of 47 DOTs, 96%), existing bridge geometry (42 of 47 DOTs, 89%), and the size of the bridge (41 of 47 DOTs, 87%) were highly considered by most DOTs.

Regarding construction management factors that impact strategy selection for complex bridge replacements, the contract period strategy, including considerations like working days, calendar days, and incentive/disincentive systems (A+B), was considered by 39 of the 47 DOTs (83%). Construction season factors, such as weather conditions and project duration, were also considered by 38 of the 47 DOTs (81%). PDMs, including D-B-B, D-B, CM/GC, and P3, were factored in by 36 of the 47 DOTs (77%). Additionally, demolition constraints and construction techniques were important for 34 and 33 DOTs, respectively. Cost considerations were another critical factor, with direct costs being the most frequently considered by 42 of the 47 DOTs (89%). Funding constraints influenced decisions, as 37 of the 47 responses (79%) noted. Asset life-cycle costs were considered by 35 of the 47 DOTs (74%).

Strategies used to gain buy-in from stakeholders were also examined. Frequent in-depth communication with stakeholders was the most commonly used strategy, employed by 40 of the 47 DOTs (85%). Providing a project website was another effective approach that 39 of the 47 DOTs (83%) utilized. Discussing the benefits of the strategy was cited by 36 of the 47 DOTs (77%), helping to clarify the project’s value and expected outcomes. Ten DOTs also noted using white papers to provide detailed information about the project scope, objectives, and methodologies. Negotiating property improvements was also noted as an alternative strategy for gaining buy-in.

DOTs reported that, based on past experiences, they updated policies and practices in various areas. Changes included the incorporation of incentive and disincentive clauses (33 of 44 respondent DOTs, 75%), communication with the community (32 of 44 DOTs, 73%), and design (31 of 44 DOTs, 70%), project scheduling and management (30 of 44 DOTs, 68%), and use of innovative materials or construction techniques (28 of 44 DOTs, 64%).

The survey highlighted diverse strategies and considerations employed by DOTs for bridge replacement projects in complex scenarios. The findings underscore the use of flexible and adaptive approaches.