It All Started With A $10 Bill

Sunday, November 11th at 2 pm is a big day for the Stearns Truss in Delphi.  It culminates nearly two years regular M-W-F work by an ingenious volunteer crew  This whole project started December 16, 2005 in a Pulaski County Commissioner’s meeting at Winamac.  Four Canal Association volunteers were present.  An offer to purchased the 78 foot long relic for $10 was met with a stipulation that it must be removed from the Big Monon Ditch in just three months.  That winter the weather was cooperative and the volunteers rallied to disassemble and transport all the pieces to Delphi by March 3rd.

CELEBRATE!!  Volunteers are ready to present their pride and joy.  This bridge is a “one-of-a-kind” lightweight, portable, once rusty, wrought iron span brought from near Medaryville.  It is a special lightweight span designed by Wm. Stearns and the last known of its type to exist in the US.  The special place where the BIG BLUE BRIDGE spans the canal is in west Delphi behind Pizza Hut / Dairy Queen.  It sits over a reconstructed section of the Wabash & Erie Canal.

The last task being completed is the handrail and some touch-up of the beautiful blue paint.  The bridge sports another color as well as the blue.  All iron that was added for safety, but not part of the original, is painted black.  This comprises the safety siderail which is made of angle iron with a similar look as the integrated original handrail thus the added materials are black.

With parking near the bridge a premium on dedication day the participants can enjoy parking downtown Delphi around the Court House and being chauffeured by Brian Stirm and his popular Trolley.  Ride to the dedication then back downtown and “Discover Delphi Days” at the participating stores.  The Trolley will also travel to Canal Park and the whole circuit every 20 minutes.  It runs from 12 noon to 4 pm both Saturday and Sunday (10th and 11th).  Take time to enjoy the small town flavor with a visit to this county seat that still looks like it did in the historic canal era.

Take a walk along the trial from the bridge and jaunt south on the towpath to Lock #33 or the Irish Construction Camp  — or go north and arrive by trail in a half mile at the Canal Interpretive Center.  The volunteers are developing several sites with relevant canal connections to the 1840s through the mid 1870s.  Just west of the Blue Stearns Bridge were Papermills and Delphi’s shipping connections brought goods from the east while local products of salt pork, grain and lime were sent afar on this manmade waterway.

Come to the dedication and visit with the many volunteers that have rallied to this restoration project.  Nearly a dozen of the 76 volunteers listed on the program have been as regular as “clockwork” and have keep the pace throughout the last 7 seasons with their M-W-F workdays.  Without this dedication and the personal donations and grant support for supplies and materials this would not have happened.  Thank the volunteers when you meet them in the reception line spanning this 78 foot long wrought iron bridge.

If you are coming to Delphi on Saturday you have several treats to expect.  First the Trolley is running from downtown to the Stearns Truss from 12-4 pm and it is an informal “look-see” of the bridge — a few volunteers will be present.  Second there is another dedication of a downtown historic property’s shinny new facade — the Opera House.  The Delphi Preservation Society is cutting a ribbon to highlight to the public this completion at 2 pm on Saturday.

Take some time and exploring the shops and their specials during Discover Delphi Days all weekend.  You can park on the Square and board the trolley in front of the Opera House building on either Saturday or Sunday 12-4 pm and ride out to see the bright blue Stearns Truss Bridge.

Hays Street Bridge Restoration

Patrick Sparks

Sparks Engineering, Inc. (

In the early 1900s the Galveston, Harrisburg, and San Antonio Railway was in the midst of an expansion from the City of San Antonio, Texas, westward, and as its tracks intersected the city’s existing roadways, the railway was required to construct above-grade crossings for horse-drawn carriages and, later, motor vehicles. In 1910 a viaduct was required to carry Hays Street over two active railroad tracks and two city streets, and to economize, the railroad decided to move two narrow-gauge iron trusses that formed a bridge over the Nueces River in southwest Texas to the San Antonio location. One truss was a 130 ft long 1910 Pratt truss and the other a more historically significant 225 ft long Whipple truss, both produced in 1881 by the Phoenix Bridge Company of Phoenixville, Pennsylvania. In the process of connecting the trusses to form the new bridge in San Antonio, the railway widened both spans from 16 ft to 25 ft, and constructed 1,000 linear ft of concrete approach spans. The Whipple truss, one of only six such trusses remaining in Texas, and one of the few remaining trusses with Phoenix columns in the country, featured segmental wrought iron columns, cast-iron joint blocks, and early laminated steel pins.

The bridge served its purpose dutifully as the region grew, but by the early 1980s it was determined to be structurally deficient and was closed to vehicular traffic. A movement began to replace the bridge, but in the 1990s, Douglas Steadman, P.E., formerly the president of W. E. Simpson Company in San Antonio, identified the trusses as historically significant and successfully lobbied for their inclusion on the list of Historic Civil Engineering Landmarks of Texas in 2001.  Steadman then led an effort to obtain grant funding and private contributions to save the trusses and convert the bridge for use as a pedestrian and bicycle crossing.

Thanks in part to those efforts, the bridge was recently rehabilitated and transformed by the City of San Antonio under a grant from the Texas Department of Transportation. Sparks Engineering, Inc., of Round Rock, Texas, served as the design consultant for the project. The work involved rebuilding the bridge’s two elevated concrete approaches, structurally rehabilitating the truss spans, and adding lighting, landscaping, and interpretive signage. The design team identified the following key goals for the project: safety, utility, beauty, permanence, and economy.

The design assures compatibility with the bridge’s historic character, in accordance with The Secretary of the Interior’s Standards for Rehabilitation (36 CFR §67.7). The iron trusses are the principal historic features of the bridge and had to be preserved.

Because of extensive deterioration, entirely new approaches were designed.  The characteristics of the approach spans that the team chose to maintain in the new design are the basic 1910 alignment and profile, although slight modifications were made in slope to improve the crossing’s accessibility and its vertical clearance above the two street crossings.  The new approaches are 15 ft wide, much narrower than the 30 ft width of the 1910 approaches, which opens up the space beneath the bridge visually and creates greater opportunities for plantings, seating, and interpretation installations at ground level. This design is compatible with the size, scale, and character of the neighborhood and surrounding environment, as recommended by the Secretary of the Interior’s Standards. The new approaches are of cast-in-place concrete, with a slender profile and tapered brackets that recall the character of the 1910 work.  Using mostly single-column supports at 40-ft on-center lends elegance to this dominant part of the project.  This scenario also represented the least cost, longest life-cycle, greatest utility, and best potential for aesthetic excellence.

The two historic trusses were in essentially good condition but with some areas of serious corrosion. The original materials were wrought iron and cast iron (used in the joint blocks in the Whipple span), which have very good durability The elements having the highest amounts of corrosion were those steel elements that were added in 1910, including lateral struts on the Whipple span and miscellaneous stiffening angles and cover plates on the floor beams.  The unusual laminated steel pins of the Whipple truss had detectable corrosion pits in some locations.

Because the geometry and sections of the main members are relatively simple to model, material characterization became the key issue in the structural analysis of the bridge. A rigorous evaluation was necessary because the materials were of unknown quality, the critical fabrications were never quality-checked by modern standards, design loads have increased over time, and the effects of decay and fatigue may have reduced the members’ capacity. On the other hand, the importance of bridges such as this one as significant icons of history requires that our evaluation methods be as least invasive as possible. So it was not feasible or appropriate to remove sufficient material to test the material properties in a laboratory. Instead, we used in-place nondestructive methods. In addition to a visual assessment and structural analysis, we relied on a combination of materials characterizations and nondestructive testing. In this approach, data regarding the elements’ microstructure, hardness, and chemical composition, together with other historical data, are used to characterize the behavior of the material without the need for physical sampling.

On the basis of the findings above, the team determined that the two truss spans could indeed be rehabilitated for use in the pedestrian crossing. The trusses themselves did not have to be strengthened, but corrosion was repaired and those diagonal members that had bent over the years were straightened. The center and top lateral struts of the Whipple span had been lengthened in 1910 with steel, not wrought iron, and these were severely corroded. The team therefore replaced them with weathering steel, a substitute material that is resistant to corrosion. All of the floor beams of the Whipple truss had to be rehabilitated and their corroded cover plates replaced. Two of the floor beams were removed from the truss for repair, but the remainder were rehabilitated in place.

In keeping with the practices used in constructing the truss, the team used traditional hot riveting methods rather than, as is more conventional, replacing the rivets with bolts. A special crew was trained in hot riveting in order to accomplish this, and the process was videotaped and posted on Hot riveting was also used to replace corroded rivets throughout the trusses. Pack rust was removed from many of the floor beams and vertical members; in some cases the team removed the rivets in order to do this, but in some cases a technique developed by the riveting consultant was used whereby the rust was loosened from the crevices with the aid of a rivet hammer.

The deck was replaced with lightweight, foot-friendly 2 × 6 pressure-treated lumber.  Only the floor beams were painted and the upper truss members were given an appearance coat of linseed oil.

The project was funded by a TxDOT Enhancement Grant, private donations, and the City of San Antonio. Plans and specifications were completed in September 2006, and the project was bid in early 2009. Construction began shortly thereafter and was completed in the spring of 2010.

The design required flexibility to meet current code requirements, ensure compatibility with the bridge’s historic character, and stay within budget.

In addition to the truss rehabilitation and the reconstruction of the concrete approaches, the project included architectural and pedestrian lighting, interpretive signs, and a landscaped entry plaza.  The $3.2-million project also included badly needed drainage improvements and repairs to broken and clogged storm sewer pipes in the neglected neighborhood nearby.

As a pedestrian bridge that will serve as a link between the east side of San Antonio and its downtown, the newly renovated Hays Street Bridge is inviting to all, providing not only a sense of community as an area of recreation but also as an attraction for visitors.

S. Patrick Sparks is the principal of Sparks Engineering, Inc., Round Rock, Texas.

Bridge Facts:

Total length of viaduct:  1,400-lf

Historic spans: 225-lf Whipple + 130-lf Pratt

Cost of project: $3.2 Million

Owner: City of San Antonio

Prime Consultant: Sparks Engineering, Inc., Round Rock, Texas

Site/civil engineer: Garcia & Wright, San Antonio, Texas

Contractor: Jay-Reese Contractor, Inc., Austin, Texas

Landscape architect: Bender Wells Clark, San Antonio, Texas

Electrical Engineer: Joshua Engineering Group, San Antonio, Texas

Riveting Consultant: Vern Mesler, Lansing, Michigan


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