2015 New Jersey Historic Preservation Awards Program Application

Rosemont-Raven Rock Road Bridge Rehabilitation

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Submission Information

Submission Name:Rosemont-Raven Rock Road Bridge Rehabilitation

Location/Address of Entry:Lockatong Creek, Delaware Township, Hunterdon County

Nominated by:Todd Batchelor, Project Engineer

Organization:TranSystems Corporation

Address:1037 Raymond Boulevard, Suite 400, Newark, New Jersey 07102

Day Telephone:201.334.1461FAX: 973.741.2414

E-Mail Address:

Application Information Checklist

BCategory – Please select A, B, C, or D

XNomination Form

XNarrative, comprised of 10 pages

XProject Cost

XList of Project Team Members with mailing addresses included

XTime required to complete the project

XPhotographs included. Number of photos 34 (See Appendix A)

XCD-Rom included. Number of images 34 (Two (2) CD-Roms of images included – pdf of full application submission included on CD 2)

XMaps included and number of maps 1 (See Appendix B)

XArchitectural drawings/renderings folded to 8.5” x 11”. Number of documents 19 (See Appendix C)

XLetters of support included and number of letters 3 (See Appendix D)

Other attachments are listed on a separate sheet of paper

Narrative

Introduction

The Rosemont-Raven Rock Road Bridge, also known as Bridge D-300, is a single span, wrought and cast iron, pin-connected Pratt through truss bridge that is owned and operated by Hunterdon County. The structure carries Rosemont-Raven Rock Road over the Lockatong Creek in Delaware Township, New Jersey (refer to Project Location Map in Appendix B).

According to recent research performed by Marfy Goodspeed to commemorate the bridge's rehabilitation project, the stone masonry abutments date to a previous crossing of the Lockatong Creek destroyed during an early October 1877 flood. Her research also uncovered Hunterdon Republican newspaper records indicating that a request for proposals for a new all wrought iron bridge crossing of the Lockatong Creek was placed in early November 1877 and received a week later. The project was awarded to the Lambertville Iron Works of Lambertville, New Jersey in late November 1877 for a bid of $2,850. The bridge tension members, compression fitting castings, and decorative work were fabricated by the Lambertville Iron Works and compression member Phoenix columns were fabricated by the Phoenix Iron Company of Phoenixville, Pennsylvania. The bridge was erected by the Lambertville Iron Works and was opened to traffic in 1878.

The Lambertville Iron Works has a rich history in Hunterdon County and is recognized as one of the county's foremost second-half of the 19th century foundries. Beginning operation in 1857 as Laver & Cowin, the works was known for its owner William Cowin and his three (3) cast iron and wrought iron spans designed by Trenton engineer Francis C. Lowthorp and built in Clinton, Glen Gardner, and Hampton between 1868 and 1870. By the time of Cowin's death in 1874 William Johnson was general manager of the works. Prior to holding the general manager position Johnson was a master machinist with the works and the holder of several bridge, boiler, and machine related patents. It was Johnson who proposed on the Rosemont-Raven Rock Road Bridge in 1877.

The Phoenix column, consisting of wrought iron segmental channels riveted together to form a circular tube of great compressive strength, was developed in 1862 by Samuel Reeves of the Phoenix Iron Company. The patented section was used by both the Phoenix Iron Company and other companies, such as the Lambertville Iron Works, in the erection of bridges as well as buildings, viaducts, and elevated lines. By joining the compressive members through fittings at cast iron nodes, the Phoenix column “was a great factor causing the substitution of wrought iron for cast iron in compression members of pin-connected bridges“, according to noted engineer and author J.A.L. Waddell.

The Rosemont-Raven Rock Road Bridge is 127’-6” long, center to center of end bearings, and 17’-0” wide, center to center of trusses. The bridge roadway carries a single lane of opposing two-way traffic. The span is comprised of two (2) nine panel wrought and castiron, pin-connected Pratt through trusses supporting floorbeams, stringers, and asphalt-filled galvanized corrugated steel bridge flooring. The trusses are approximately 17’’-3” deep. The interior verticals, upper chords, and inclined end posts are all patented Phoenix column compression members comprised of four (4) channel sections. These members are joined at each panel point with distinctivecast iron compression fittings fabricated locally by the Lambertville Iron Works. The connecting pins for the eyebar and counter rod members pass through these castings. Tension diagonals, end verticals, and lower chord members are made up of unique square cross-section eyebars as opposed to the more common rectangular cross-section. Diagonal counters consist of rods with loop forged eyes and adjustable sleeve nuts. The upper chord bracing system consists of transverse I section struts and lateral bracing rods connected at the upper panel point castings. The lower bracing system is a unique system of rods that join at a center ring. Outstanding decorative features include cast iron ball and spire finials at each upper chord panel point, cast iron filigree portal bracings, and bridge plaques mounted on the portal struts. The lattice railings consist of riveted plate and angle members with decorative cast iron end posts that are connected to the truss shoes. The lattice railings are connected to the vertical truss members with decorative cast iron spacers and tie washers. The truss expansion bearings are nested rollers. The bridge is supported on ashlar abutments with flared wingwalls. Both approaches are signed for a 5 ton gross weight limit and a 12 foot vertical clearance.

Prior to this rehabilitation project the bridge had been subjected to several modifications over its lifetime including the following work:

  • Replacement of the deck and stringers with modern materials,
  • Installation of welded cover plates at the floorbeams,
  • Installation of welded plates between the floorbeams and their u-bolt hangers,
  • Installation of random welded attachments to the trusses, remnants of which remained,
  • Installation of localized welded repair plates on the Phoenix column members,
  • Installation of welded angles on the upper chord Phoenix members,
  • Installation of welded supplementary struts and connection plates at the inclined end posts,
  • Installation of welded supplementary members and connection plates at the end vertical hangers,
  • Installation of welded knee braces between the interior vertical truss members and upper chord lateral struts,
  • Installation of welded modern turnbuckles in several counter members,
  • Removal of portions of the cast iron portal bracing filigree to accommodate the welded repairs to the end vertical hangers,
  • Installation of welded repairs and replacement sections of the lattice railings,
  • Insensitive repairs to the finials, and
  • Insensitive repointing of the abutments and wingwalls.

The bridge had also experienced age-related physical material deterioration despite regular maintenance, localized vehicular impacts, and structural capacity issues. Its location on a lightly traveled rural road had helped to preserve the bridge by limiting exposure to traffic.

Despite the alterations listed above, the bridge was a well preserved example of its type and technologically distinguished as one of the earliest and most complete bridges built with Phoenix columns in the state. It is also the work of the Lambertville Iron Works, successor to the firm that fabricated the most important 19th century bridges in the region.

The Rosemont-Raven Rock Road Bridge has been determined eligible for the National Register of Historic Places.

Description of Project Activities

Preparations for this first comprehensive rehabilitation of the bridge began in 2002 with an in-depth physical inspection, a load testing program, a structural analysis, and a concept study that established the project scope of work, all performed and coordinated by TranSystems (formerly Lichtenstein Consulting Engineers). In conjunction with the final design development by TranSystems, a public involvement program was conducted in 2008 to help gauge public reaction to the project. Consultation with the public was continuous throughout the project’s final design and construction phases due to their strong attachment to the bridge and desire to see it preserved. The rehabilitation work was completed during an uninterrupted shutdown of the bridge from spring 2013 to late summer 2014. TranSystems was tasked with providing construction support services to the county during the construction phase to ensure that the bridge rehabilitation work proceeded in accordance with the Secretary of the Interior’s Standards for Rehabilitation.

The Rosemont-Raven Rock Road Bridge was nearing the end of its useful life. Rehabilitation of the bridge was necessary to maintain the transportation corridor and to protect public safety. The bridge had experienced widespread physical deterioration, had insufficient structural capacity, and had inadequate safety features. Over time the bridge’s physical condition had suffered due to significant deterioration and the introduction of visually incompatible features to this historic structure. Long-term moisture exposure, vehicular impact damage to truss members, and the demands of modern day traffic usage were accelerating its deterioration. As a direct result of the physical deterioration the capacity of the floor system members were well below the project’s H15 truck design loading. Several Phoenix column members also had insufficient structural capacity. Although numerous repair projects had been performed to the bridge in the past, there are no records of a comprehensive rehabilitation of the bridge having taken place. Aesthetic details, particularly the portal bracing and lattice railings, had been altered with unsuitable modifications over time. Welded supplementary members and components were aesthetically and technologically inappropriate for the bridge (refer to Photographs 1 and 3 in Appendix A).

Through intensive study and alternatives analysis, it was determined by the conclusion of scoping that the then 130-year old bridge could be rehabilitated and continue to serve the traveling public’s needs. From the outset of the scoping project the goal of retaining as much historic fabric as possible guided the work performed to the bridge. The work undertaken at the Rosemont-Raven Rock Road Bridge consisted of the following rehabilitation activities (refer to selected drawings in Appendix C for further details):

  • Bridge relocation and complete bridge disassembly at the east approach roadway, transportation of truss members and decorative elements to a specialty fabrication shop for repair, and on site reassembly and placement in its original location. Disassembly was deemed to be the prudent option for truss rehabilitation due to the need for truss member replacements and repairs and the need for pin replacements. Furthermore, member repairs made in a shop environment are superior to those performed on site. A comprehensive member match marking plan was developed by the engineer and contractor to ensure that all bridge elements would be returned to their original locations and orientations upon reassembly (refer to Photographs 5 and 6),
  • Removal of deteriorated and structurally inadequate stringers and floorbeams and replacement with new galvanized and painted high strength steel elements matching the overall shape of the original members (refer to Photographs 7 and 8),
  • Removal of existing asphalt-filled galvanized corrugated steel bridge flooring and replacement with new corrugated steel flooring and compression seal deck joints (refer to Photographs 3, 4, 7, and 8),
  • Removal of newer concrete bearing seats, replacement of underlying deteriorated bearing seat stones with locally quarried material, and construction of new cast-in-place reinforced concrete backwalls (refer to Photographs 7 and 8),
  • Complete cleaning and repointing of the stone masonry abutments and wingwalls using accepted practices and compatible materials (refer to Photographs 7 and 8),
  • Installation of a new custom designed bridge railing system, designed to AASHTO specifications using square tube elements. Although a new element on the bridge, these railings effectively protect the truss lines from vehicle impacts. They are attached to the new floor system rather than the trusses and could be removed in the future without physically impacting the trusses. The railingsystem lendsitself to historic truss bridges due to its simple, clean shape and open appearance (refer to Photograph 4),
  • Rehabilitation of existing lattice railings including repair of damaged decorative hardware and end posts, heat straightening of impact damaged rail elements, and refabrication of elements damaged beyond repair. Rivets matching the existing were used in the repairs and in newly fabricated work (refer to Photographs 9, 10, and 11),
  • Removal of non-original welded knee braces between the interior vertical truss members and upper chord lateral strut members (refer to Photographs 12 and 13),
  • Removal of non-original welded supplementary strut members and connection plates at the inclined end post members (refer to Photographs 14 and 15),
  • Removal of under capacity end vertical hangers, welded supplementary members, and welded connection plates and replacement with high strength members matching the original dimensions (refer to Photographs 14 and 15),
  • Removal of random welded attachments to the truss members to restore the members to their original appearance,
  • Removal of modern welded turnbuckles installed in several counter members with frozen/inoperable sleeve nuts and replacement with rod material and coupler nuts. Restoration of tension adjustment function to all original sleeve nuts at the counter members (refer to Photographs 16 and 17),
  • Repair of impact damaged truss members (including tension members, counters, and lateral bracing rods) using heat straightening and shortening methods. Heat straightening and shortening is not a commonly applied method of bridge repair and can be described as more of an art than a science that requires years of experience to master. In order to ensure successful application of the methods, careful inspection of the members was necessary and detailed contract documents were prepared to limit the work to qualified contractors and the repair procedures to accepted practices. The use of this repair method resulted in the retention of original members that might have otherwise required replacement (refer to Photographs 18 and 19),
  • Repair of material losses at the eyebar heads with pad welding. Pad welding is a method of building up weld filler material to restore members to their original dimensions. Material testing was performed using the original end vertical hanger members that were proposed for replacement. Testing results indicated that the cast iron eyebar material was weldable. The use of this repair method resulted in the retention of original members that might have otherwise required replacement (refer to Photographs20 and 21),
  • Removal of the welded supplementary angles that were previously installed at the upper chord members. Upon removal of the angles it was determined that the material losses to the original Phoenix column member surfaces due to long-term trapped moisture were beyond repair and that the originally proposed scheme of strengthening these members with internal tubes was no longer a viable option. Instead, after consultation with the SHPO, the upper channels of the members were replaced with new material that dimensionally matched the original members. The new channels were fabricated using stock high strength structural tube sections that were cut and then welded to plate flanges. The new channels were riveted to the existing members matching the original construction. Upon completion and painting of these new channels it is difficult to distinguish between new and old. In conjunction with the member disassembly, the interior surfaces of the upper chords and inclined end posts were completely primed to ensure long-term durability (refer to Photographs 22,23, and 24),
  • Installation of bolted repairs at lower ends of the Phoenix column vertical members to offset holed through areas and material losses noted at the interior surfaces (refer to Photographs 25 and 26),
  • Shop replacement of deteriorated rivets at the Phoenix column members,
  • Replacement of all truss pins and pin nuts with high strength, non-galling, stainless steel material (refer to Photographs 12 and 13),
  • Complete rehabilitation of the frozen/inoperable truss expansion bearings including replacement of rollers and plate components with high strength, non-galling, stainless steel material. The truss shoes and masonry plates were also faced with stainless steel plates. Damaged areas at the cast iron truss shoes and masonry plates were repaired to restore the external appearance of the truss bearings (refer to Photographs 27, 28, 29, and 30),
  • Rehabilitation of the upper chord finial balls. Several of the cast iron finial balls had previously cracked and the damaged areas were sealed with silicone. These damaged areas were repaired with weld material by the fabricator to provide a permanent repair (refer to Photographs 31 and 32),
  • Rehabilitation of the truss portal bracings. These decorative castings were previously broken at the end upper chord panel point locations to accommodate connection plates for the supplementary welded end vertical hangers. The fabricator duplicated the original decorative pattern and recreated the broken areas, making the repairs difficult to distinguish from the original material (refer to Photographs 33 and 34), and
  • Shop blast cleaning and painting of the disassembled truss members (refer to Photographs 2 and 4).

Approach roadway work includes milling and repaving of the roadways and installation of an approach guide rail system attached to the new bridge rails.

Project Goals, Objectives, Impacts, and Benefits