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Section 2: Historic Bridge Team Report

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Overview

The purpose of the Historic Bridge Team (HBT) Report is to provide a summary of information required to assist in completing the Section 4(f) process. The Bridge Project Manager produces the HBT Report with information from the condition assessment report and with input from the District Environmental Coordinator, TxDOT ENV, and the Bridge Division design engineer. The final HBT Report is an engineering document, and must be signed and sealed for regulatory approval by the Bridge Project Manager.

The HBT Report consists of a summary of bridge information, a need and purpose statement, a statement of historic significance, an alternatives analysis, and a recommendation for the preferred alternative. A flowchart illustrating the processes involved in a historic bridge preservation alternatives analysis can be found on the TxDOT website. Each of the components of the HBT Report is discussed in more detail below.

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Bridge Information

The Bridge Information section provides a summary of general information about the bridge and the site, including the condition assessment and inspection information.

The following items should be included in the Bridge Information section:

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Need and Purpose Statement

The purpose of developing a bridge project is to ensure safety by remedying structural, geometric, or other functional deficiencies. Need and purpose statements outline the specific deficiencies and problems associated with the existing facility, and justify why a proposed project is necessary by establishing the objectives of the project.

Establishing a detailed need and purpose statement is vital to the development of the Programmatic Section 4(f) Evaluation since this statement lays the foundation for the alternatives analysis. Coordination is required between the District EC or ES developing the need and purpose statement, the BRG PM developing the alternatives analysis, and the ENV HIST developing the NEPA documentation, as these documents must be parallel.

The most important part of the need and purpose statement is establishing the need for the project by describing the deficiencies that exist and providing the justification for the expenditure of public funds to correct those deficiencies. The statement must be specific and detailed in describing the conditions that result in the deficiencies, including structural and functional deficiencies that will be addressed by the project. Include as much supporting information as possible.

The purpose defines the objective for the project and focuses on the desired outcome for the traveling public. The need for the project should be established first and the purpose determined second; for this reason, this statement is sometimes informally referred to as the need and purpose statement.

Issues discussed in the need and purpose statement should include as much of the following information as is relevant to the project:

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  • Narrow width. Describe the types and widths of vehicles using the bridge if the bridge deficiency is due to horizontal clearance. Indicate if impacts or crashes have resulted from narrow width.
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  • Insufficient height. Describe the types and heights of vehicles using the bridge if the deficiency is due to vertical clearance. Indicate if impacts or crashes have resulted from insufficient height.
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  • Increase in traffic. Provide ADT to show increase in traffic. If increase is situational and not supported by ADT, describe the situation that results in the increase in traffic. For example, if the bridge is the sole route available when other routes are blocked by train traffic, flooding, or some other temporary event, describe the event and provide an approximate increase in traffic.
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  • Types of traffic. Describe the types of vehicles accessing the bridge, and why these vehicles create a deficiency.
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  • Accident history. Describe accident history at the bridge, and why the accident history is the result of a bridge deficiency. For example, poor alignment or sight distance could result in accidents.
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  • Load capacity. Indicate the current and required load capacities for the bridge.
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  • Physical deterioration of bridge. Describe specific areas of deterioration and how they result in a deficiency. For example, deterioration often results in reduced load capacity. Issues such as scour, however, may not immediately affect load capacity but will need to be addressed to prevent future reduction in capacity. Be specific.
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  • Deficient railing. Describe the railing and its deficiency, and provide information about any accident history involving the deficient railing.

Functional obsolescence due to inadequate horizontal or vertical clearance is a common problem that should be addressed on historic structures, if possible. Vertical clearance restrictions caused by portal or other bracing on historic truss bridges should be carefully evaluated to ensure passage of essential service vehicles. Crash-tested rails should be added if possible; however, horizontal clearance, bridge geometry, and connection details present significant challenges for rail upgrades. At minimum, delineation of obstructions and bridge members located at the roadway level is required. In either case, coordination with BRG is required to determine the best course of action.

Guidance for developing a well-defined need and purpose statement is available on TxDOT ENV’s website. Contact your ENV Historian for additional guidance, if required.

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Statement of Historical Significance

The statement of historical significance details how the bridge meets the criteria for listing in the National Register of Historic Places. The statement also identifies the historic character-defining features of the bridge that must remain in any proposed project, in order for the bridge to continue to convey its significance. ENV writes the statement based on documents on file.

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Alternatives Analysis

The alternatives analysis serves as the foundation for initiating the necessary environmental and engineering studies for the environmental documents, Section 106 coordination, Section 4(f) coordination, and project development. The alternatives analysis outlines the functional and structural limitations of the historic bridge being evaluated and describes the rehabilitation requirements needed to comply with the Section 4(f) alternatives. Detailed information on conducting an alternatives analysis is provided in the Section 4.

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Recommendations

The recommendations section presents the most feasible and prudent alternative that minimizes harm to the historic structure while meeting the transportation needs of the local community. The recommendation is selected based on the outcome of the Alternatives Analysis.

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