LANDING BRIDGE HAER No. NJ-74 Spanning the Raritan River at Landing Lane New Brunswick Middlesex County New Jersey
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LANDING BRIDGE HAER No. NJ-74 Spanning the Raritan River at Landing Lane New Brunswick Middlesex County New Jersey PHOTOGRAPHS WRITTEN HISTORICAL AND DESCRIPTIVE DATA HISTORIC AMERICAN ENGINEERING RECORD National Park Service Northeast Region U.S. Custom House 200 Chestnut Street Philadelphia, PA 19106 HISTORIC AMERICAN ENGINEERING RECORD LANDING BRIDGE HAER NO. NJ- 74 LOCATION: Landing Lane over Raritan River, between New Brunswick and Piscataway Township, Middlesex County, New Jersey USGS Plainfield, NJ Quadrangle, Universal Transverse Mercator Coordinates: 18.545380.4484130 DATE OF CONSTRUCTION: 1895 PRESENT OWNER: County of Middlesex, New Brunswick, New Jersey PRESENT USE: Vehicular and pedestrian bridge. To be replaced 1991 SIGNIFICANCE: Landing Bridge is a representative example of late 19th century bridge design and construction, featuring Pratt trusses and riveted connections. The bridge was designed by George F. Blakely, who was at the time chief engineer for the Passaic Rolling Mill Co. of Paterson, New Jersey. It was built by the Penn Bridge Company of Beaver Falls, Pennsylvania. Portions of the stone abutments of the earlier bridge at this location were re-used in construction of Landing Bridge. PROJECT INFORMATION: Landing Bridge was recorded in January February 1991 by the Cultural Resource Group of Louis Berger & Associates, Inc., East Orange, New Jersey, for Buchart Horn, Inc., Marl ton, New Jersey. The recordation was undertaken pursuant to a Memorandum of Agreement among the Office of New Jersey Heritage, United States Coast Guard, County of Middlesex, and Advisory Council on Historic Preservation. Project personnel included Martha H. Bowers, Architectural Historian; Alison Helms, Historian; and Rob Tucher, Photographer. LANDING BRIDGE HAER NO. NJ-74 (PAGE 2) DESCRIPTION Landing Bridge carries Landing Lane over the Raritan River between the city of New Brunswick and Piscataway Township in Middlesex County, New Jersey. The Raritan River at this point is about 350 feet wide. Because its bed lies below mean sea level, the stream has pronounced tidal characteristics, with large areas of mud flats exposed along the north bank when the water is low. Landing Bridge is the northernmost of three vehicular crossings over the Raritan from New Brunswick, and is located in the extreme northern corner of the city. Along the south bank of the Raritan is the Delaware and Raritan Canal, constructed in 1834 and closed in 1933. Landing Lane is carried over the canal on a plate girder cantilever swing bridge erected in 1920. Beyond the canal, to the south, are residential neighborhoods of single family dwellings and large apartment buildings. On the north (Piscataway Township) side of the Raritan, the immediate area consists largely of wooded parkland. Portions of the park to either side of Landing Bridge contain archaeological remains of Raritan Landing, important during the 18th century as a commercial and trade center. Landing Bridge is a three-span, steel Pratt through truss structure erected in 1895 to replace a wooden covered bridge at this location which was destroyed by fire. Landing Bridge is 360 feet 7 inches long, and 28 feet 2 inches wide (out to out). It incorporates portions of the earlier substructure in each abutment. The north abutment is constructed of coursed, quarryfaced red-brown stone, and has rounded corners. The U-shaped wingwalls are of reinforced concrete, and the truss is seated on large granite blocks. The south abutment presents a substantial breast wall of mass concrete, behind which are large sections of quarryf aced stone. The two river piers, set on spread footings, have battered up- and downstream faces, and triangular nosings on the upstream ends to reduce the force of water and ice. The visible material of construction is unreinforced concrete; the extent to which they may have incorporated portions of earlier piers is unknown. The three Pratt truss spans measure (south to north) 119 feet 4 inches, 116 feet and 116 feet 1 inch long, center to center of bearings. Except at the bottom chord-inclined end post connections (which are pinned), all connections are riveted. The trusses are about 18 feet deep and are set 20 feet 11 inches apart, center to LANDING BRIDGE HAER NO. NJ-74 (PAGE 3) center. They accommodate an 18 feet 9 inches roadway edged with steel channel wheel guards and steel beam guard rails. A 5 feet 6 inches wooden sidewalk supported on channel stringers is carried on cantilever angle brackets extended from each panel point of west trusses. It is edged with an ornamental iron railing 3 feet 10 inches high (Buchart Horn 1990:1-2). The three spans are essentially identical. Each truss is divided into eight panels. Top chords and inclined end posts have box sections built up from top plate, side channels and bottom bar lattice. Diagonal and end verticals are composed of double angle flanges and bar lattice, while intermediate verticals consists of paired channels joined by double bar lattice. Three of the original end verticals of the north span have been replaced with rolled flange sections. In addition, rolled channels have been used to reinforce most of the intermediate verticals in all three of the west trusses. Two angles form the counters in the two center panels of each truss. Angles also form the upper lateral bracing, while double lattice is used for the sway frames and portal frames. The sway frames are stiffened by slender angle knee braces. Atop the north and south portals are builder's plates surmounted by small plates in which "1895 11 is cut out in stencil fashion. Each builder's plate bears the following inscription: 1895 Erected by the Board of Chosen Freeholders of Middlesex County Michael Welsh, Director George H. Blakely, Consulting Engineer Penn Bridge Co. Builders, Beaver Falls, Pa. The bottom chords of Landing Bridge are fashioned from two pairs of angles joined at intervals with web plates (except at the two center panels of each truss, where the plate is continuous). The chords of the east trusses have been reinforced with plates. Riveted floor beams are placed below the bottom chords at each panel point. The floor beams carry rolled I-beam stringers which in turn support 5" crossbeams over which is laid open-grid steel decking. Attached to all intermediate floor beams are inverted queen-post trusses equipped with turnbuckles to permit tension adjustment. Angles are used for bottom lateral bracing. The bridge appears to have originally been illuminated only by two LANDING BRIDGE HAER NO. NJ-74 (PAGE 4) lamps, set on iron posts located along the sidewalk railing, one at the south portal, the other at the north end of the south span. currently the bridge is equipped with fluorescent lighting suspended from lateral struts above the roadway. Landing Bridge has been repaired numerous times since its construction. The first major work occurred in 1939, when the structure's original wooden de.ck was replaced with reinforced concrete and the bridge was reinforced to increase the live load capacity (Buchart Horn 1990:4). Plates were added to many truss members, for example on the bottom chords and on the faces of all the diagonals in the east trusses except for those in the two center panels. To carry the greater weight of the new deck, the inverted queen post trusses were added to all the intermediate floor beams. Winter roadway deicing with salt resulted in significant deterioration of the floor system and lower chords, particularly on the east side, which, unlike the chords of the west trusses, were not protected from runoff by the presence of a sidewalk (Buchart Horn 1990:4). In 1965, major rehabilitation was again undertaken, during which the reinforced concrete floor was removed and replaced with a lighter timber deck overlaid with bituminous asphalt. Other work included reinforcing nearly all the verticals of the west trusses with channels, and replacing the gusset plates connecting the diagonals and counters in the center panels of the east trusses. A third large-scale rehabilitation was undertaken in 1972. The by now rotted timber deck was replaced with the existing open steel grating, which required installation of new crossbeams, and many truss members were again reinforced or repaired. By 1989, however, the bottom chords had greatly deteriorated, and shear cracks were visible on many floor beams (Buchart Horn 1990: 5-6). Landing Bridge is currently posted with a 3-ton load limit and is scheduled for replacement in 1991. The Pratt truss type is characterized by parallel top and bottom chords, with verticals in compression and diagonals in tension. It was first patented in 1844 by Thomas and Caleb Pratt. It proved to be extremely popular among engineers and bridge builders, due to its strength, simplicity of design, and adaptability to many different loading and siting situations (Jackson 1988: 24). Through most of second half of the 19th century, Pratt trusses (as well as LANDING BRIDGE HAER NO. NJ- 74 (PAGE 5) most other iron and steel truss types) were built with pinned connections. Unlike British and European engineers, who greatly favored riveted construction, American engineers for the most part preferred to use pinned connections, particularly for highway bridges where the relative flexibility of pinned trusses presented no concern. Pinned trusses featured a limited number of connections, and driving pins was easier and quicker than riveting in the field. As important, pin-connected spans required fewer, and less skilled, workmen to erect (Edwards 1959: 104; Cooper 1889:41). In the late 1880s and early 1890s, however, major improvements were made in the development of portable pneumatic riveting systems, and by the turn of the century most American truss bridges were built with riveted connections (Jackson 1988:29). HISTORICAL INFORMATION Background At the north end of Landing Bridge is the site of an extinct 18th and early 19th century port known as Raritan Landing.