Gulph Creek Stone Arch Bridge - Delaware Department of ...

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Chapter 3—Historic Context for Common Historic Bridge Types Figure 3-71. Fullersburg Bridge (1924), spanning Salt Creek at York Road, Oak Brook, Du Page County, Illinois. This is an example of a T-beam concrete bridge. 3-71a. Elevation view 3-71b. View of T-Beams on underside of superstructure. 3-90
Chapter 3—Historic Context for Common Historic Bridge Types 3.3.4 Reinforced Concrete Channel Beams History and Description: Channel beam bridges have been built since the 1910s, and were a standard type developed by some state highway departments in the second or third decade of the twentieth century. They are most often found in simplespan lengths of less than 50 feet. Channel beam bridges are similar to T-Beam bridges in that the stems of the adjacent channel beams extend down to form a single stem, but this type differs from the T-Beam because there is a full-length seam or joint along the bottom of the stem. Primary reinforcing steel consists of stem tension reinforcement located longitudinally at the bottom of the stem, and shear reinforcement or stirrups located higher up in the stem legs. Channel beam bridges are usually precast but may be cast-in-place. When precast, the structure may be conventionally reinforced or prestressed. Cast-in-place channel beams usually have a curved under-beam soffit (without diaphragms) constructed over U-shaped removable pan forms, making them appear similar to jack arch deck bridges when viewed from underneath. In Texas, a pan form girder bridge was developed in the late 1940s that also appears similar to channel beam bridges from below, but this type does not have the characteristic seam found in the channel beam bridge. Moreover, channel beam bridges usually have diaphragms, causing them to be called “waffle slabs.” Assessment: The concrete channel beam is of low to moderate significance within the context of this study. Some channel beams that retain integrity may be considered significant, such as early twentieth century representative examples of the type, those with decorative features such as a balustrade or parapet, or those that can be documented as having been built according to a standardized plans. Character-defining features that contribute to integrity include: deck, longitudinal beams, parapet or railing when integral and abutments, wingwalls and piers. Example of Reinforced Concrete Channel Beams 1. CR 4048 (Brysonia Road) Bridge (1948), spanning Pleasantdale Creek, Adams County, PA. Determined NRHP eligible as part of state-wide bridge survey. Figure 3-72 depicts an example of concrete channel beam structure. 3-91
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