Hello! Thank you for spending your last Byways session with us today. My name is Kris Thompson and I cover above-ground resources for Districts 4-0 and 5-0. Being in the heart of the concrete industry, my Districts feature many historic concrete structures. Several of the large, multi-span bridges are hitting 100 years old and are in need of attention. I’d like to talk with you this afternoon about some of the challenges we’ve faced in our open and closed spandrel concrete arch rehabilitation projects. I hope if you have had your own successful experiences with this type of resource, you’ll consider sharing them during our discussion period following the presentations.
Rehabilitation vs. Replacement?
• Purpose & Need• Condition
• Long crossings-rehab can be more cost-effective
• Small structures-often in rural areas, low ADT
SR 4018 over the former NR-eligible Delaware, Lackawanna & Western Railroad, Lackawanna County
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Presentation Notes
With a high number of concrete arches in my Districts, how does the department decide if they will rehab or replace these bridges? It is based on a number of factors. Most importantly, what are the needs of this project? What traffic does this crossing need to accommodate? Would a rehabilitation of 15 tons be sufficient? Or does it need to carry full legal loads? This drives the examination of alternatives. If a bridge cannot be rehabilitated to the level needed at the crossing without losing its National Register integrity, perhaps it’s a replacement project? Or maybe it’s a rehabilitation that’s an adverse effect with the loss of integrity, but rehabilitating what we can is part of our minimization/mitigation commitments? Frankly, with the long, multi-span crossings, if the bridge is not significantly deteriorated, it may be more cost-effective to rehabilitate it than demolish and build another one, particularly if there are difficult site constraints. Small bridges in rural areas with a low ADT might also be good preservation candidates since they may not need to carry full loads. Rehab versus replacement decisions are made on a case by case basis, taking the needs and circumstances into consideration.
Identify character-defining features
STRUCTURAL SYSTEM
reinforcement bars
concretearches
spandrel columns
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Presentation Notes
The project eventually ends up on your lap. What’s the game plan? One of the first steps Barbara talked about in successfully applying the Standards is to identify the character-defining features of the bridge based on its significance. (click, click) For a concrete arch bridge, you have the structural system, including the interplay of concrete and steel rebars (click and click), the spandrel columns, arches, and piers carrying the load.
Identify character-defining features
Decorative Elements
parapet walls
obelisks
alcoves
Substructure
piers
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Presentation Notes
(click) The substructure, including the abutments, piers (click) and wing walls can be contributing, as can decorative elements (click). Often the parapet walls (click) add to the significance of concrete arches, as do features like obelisks (click) and alcoves (click).
Protect and Maintain
• Protection: Consideration of effects via 106, 4(f) & State History Code
• Maintenance: Regular inspections but little money for cyclical preservation activities
• Small repairs by PennDOT workforce
Standard 2: The historic character of a property shall be retained and preserved.
Standard 5: Distinctive features, finishes, and construction techniques or examples of craftsmanship that characterize a historic property shall be preserved.
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Presentation Notes
You have the character-defining features; what next? When addressing work needed for historic bridges, we start at the lowest impact level. What can we do to protect them? In Pennsylvania we have the State History Code, Section 106, and Section 4(f) mandating we consider the effects of the project on the bridge. It doesn’t require a preservation outcome, but it allows for consideration of ways to avoid and minimize impacts to the resource. Can we take steps to maintain them? Bridges on our system get inspected regularly, but with 25,000+ bridges in Pennsylvania, there is little money for cyclical preservation activities, unfortunately. PennDOT bridge maintenance will sometimes complete in-house designs and labor for small repairs. In the recent past, they were largely unaware of the Standards’ existence, let alone 106 or 4(f). They were doing the best they could with the money and time allocated, but weren’t always making the most sensitive choices for long-term preservation.
Repair or Replace Features In-Kind
Standard 6. Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual
qualities and, where possible, materials.
• Schuylkill Avenue Bridge, City of Reading
• 1924
• Over Schuylkill River, local roads, railroad, industries
• High ADT
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Presentation Notes
The next level up from maintenance is repair or replacement of features with in-kind materials, design, color, texture and other visual qualities; Standard 6 addresses this level of work. This is the Schuylkill Avenue Bridge in downtown Reading, prior to rehabilitation starting. This seven-span bridge crosses the Schuylkill River, a few local roads, a railroad, and industries on the north. It’s a good example of a large bridge that wasn’t in horrendous condition, whose rehabilitation could meet the crossing’s need at a reasonable cost. As an individually eligible bridge project, we solicited consulting parties shortly after the scoping field view. The turn out was a bit disappointing, but we were able to engage the local HARB’s chairperson and the Berks County Transportation Planner. After two meetings, we landed on a plan for how to move forward, continuing consultation through construction.
Repair or Replace Features In-Kind
Standard 6. Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual
qualities and, where possible, materials.
Presenter
Presentation Notes
One of the biggest challenges was finding a color for patching that would hit a mid –tone on the bridge. After much discussion with the contractor and concrete supplier, multiple samples were cast to show color and texture on the different elements of the bridge (click and click). My favorite question on these projects has become, “So, which color concrete out of the 25 on the bridge do we match? The soot from the trains below? The salt stains on the parapets? How about the 1966 shotcrete repairs? Should we match those?” The ugly truth, which has become my nemesis, is that Knowing we cannot control for all the factors that affect each concrete pour’s color, our aim was for a middle tone in the same color family as the existing concrete. (click and click). After the consulting parties provided feedback on which samples they thought were most appropriate, the contractors formed up the larger patch areas and began to pour, There were instances on the parapet wall where the posts between balustrade panels had to be entirely replaced. Still within the Standards, it’s all good….
Repair or Replace Features In-Kind
Standard 6. Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual
qualities and, where possible, materials.
Presenter
Presentation Notes
Or was it??? Anyone notice anything that looks out of place? (click) The contractor insisted he saw nothing wrong with what we are looking at.
Repair or Replace Features In-Kind
Standard 6. Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual
qualities and, where possible, materials.
How does it get from this
to this??
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Presentation Notes
How did it get from this (click) to this (click)? These photos don’t do it justice…the posts were the color of an orangesicle. Not quite what we expected.
Repair or Replace Features In-Kind
• Little built-in accountability and consequences
• Inspector unwilling to say no• Lack of communication• Special provisions not detailed enough• Inexperience
Standard 6. Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual
qualities and, where possible, materials.
How did it go so wrong?
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Presentation Notes
Click between points. Little built-in accountability. Inspector unwilling to be the bad guy/girl. Poor timing on the communication in some cases. Special provisions weren’t specific enough. Last but CERTAINLY not least, inexperience, mostly on my part.
Repair or Replace Features In-Kind
Standard 6. Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual
qualities and, where possible, materials.
Presenter
Presentation Notes
This is not a new problem. Wrestling with how to visually minimize the effects of concrete repairs up against old concrete of many, many different tones and shades of grey and tan. About eleven years ago, the District took a chance on a coating system on the beautiful Lindbergh Viaduct in Reading. Multiple spans, over a park, lots of pedestrians up top. (click, click) Although it looks fantastic from afar, the loads of pedestrians below and on top of this bridge see what looks like a bad peeling, sunburn. The coating failed after a few short years.
Repair or Replace Features In-Kind
Standard 6. Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual
qualities and, where possible, materials.
• Tilghman Street Bridge
• 1924
• Crosses Lehigh River, railroad, canal, local roads and new waterfront development
• Connects 2 heavily-populated sections of Allentown
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Presentation Notes
Based on past experience, we decided to take a different approach to the Tilghman Street Bridge Project. Again, like Lindbergh viaduct, it has a high pedestrian count who use the bridge to cross the river and also will host an upscale redevelopment project beneath it on the west side of the river. It’s important for this bridge to retain its integrity of materials, workmanship, and design. There will be lots of eyes up close and personal on this structure.
Repair or Replace Features In-Kind
Standard 6. Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual
qualities and, where possible, materials.
• Partnered with Chemistry Unit, Construction & Materials Lab Testing Section
• Color meter readings on good/bad colors
• Provided a range of colors within a certain delta-all in
the same color family• Goal: Quantifiable
difference
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Presentation Notes
We partnered with the construction and materials Lab testing section’s chemistry unit to develop a quantifiable way of determining if the color of the concrete patches are appropriate. Again, our goal was hitting a consistent middle tone that will blend with the existing concrete when used as patching material. We chose several places on the bridge (in blue squares) that would either be acceptable as an end color or would be completely unacceptable. The chemist took color meter readings on the acceptable and unacceptable sample areas. Knowing those values and in comparison with a color chart, we determined what delta would be acceptable – where is the range that would work. We drew a polygon on the color chart that encompassed the color tones we’d accept. We now had a measurable way of determining if a color was close enough. It was no longer an argument of opinions as it had been on Schuylkill Avenue.
Repair or Replace Features In-Kind
Standard 6. Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual
qualities and, where possible, materials.
Presenter
Presentation Notes
That got translated into the special provisions, which laid out the expectations as well as the punishment if it was not done to the Department’s satisfaction. This included the potential of only being paid for 25% of the contract bid price on the rejected area AND they’d have to apply a sealant (that would also have to go through test panel and CP review processes) OR they’d tear it out and replace it with a section that met the approved concrete color. The contractors were NOT happy. After negotiation, we decided that the meter would only come into play if there was a disagreement that couldn’t be resolved; then it would determine if the color value poured fits within the polygon on the color chart.
Repair or Replace Features In-Kind
Standard 6. Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual
qualities and, where possible, materials.
Presenter
Presentation Notes
Samples, test panels, dead men, full panels of pre-cast elements. Consulting party coordination, helping out with what should be but isn’t the easy task of finding an appropriate color, texture, aggregate mix, etc. So far, the colors and textures have been spot-on.
Repair or Replace Features In-Kind
Standard 6. Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual
qualities and, where possible, materials.
Penn Street Bridge, Reading Buttonwood Street Bridge, Reading
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Presentation Notes
Another element that often requires patching, repairing of small sections, or wholesale reconstruction (if the deck has to be removed) is the very character-defining parapet walls along with the associated obelisks, overlooks, and lighting. This is another one that I have met with varying results, more positive than the patching. These are examples from two of Reading’s concrete arches, Penn Street Bridge and Buttonwood Street Bridge. These are both cases where the contractor (same one) made an extra effort to meet with me before they started work and pull me in often to ensure they are on the right path. They also made the expected quality of the work clear to their staff, and pulled their best carpenters to build the forms to rebuild these, in some case, fairly complicated motifs. Schuylkill Avenue.
Design of Missing Features
Penn Street Bridge (1913) Reading
Standard 6. Replacement of missing features shall be substantiated by documentary, physical, or pictorial evidence.
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Presentation Notes
One of my favorite projects. City love for this bridge. Birthday party. Consulting parties came to the table with their own agendas but understood the process was about consensus-building and compromise. They had fantastic suggestions and came to meetings with an open mind. Engaged, certainly. One noticed the original obelisks with light fixtures on these old post cards and asked if we could replicate them. They had been removed, along with alcoves, at some point in the past.
Design of Missing Features
Penn Street Bridge, Reading
Standard 6. Replacement of missing features shall be substantiated by documentary, physical, or pictorial evidence.Standard 9. The new work shall be differentiated from the old and shall be compatible with the massing, size, scale, and
architectural features.
• Have documentation of original obelisks
• Consulting party coordination led to consideration of reconstruction
• Not possible-current lighting requirements would change proportions and spacing of obelisks
• Would obstruct reconstruction of overlooks
• Conclusion after discussion re: hierarchy of character-defining features
• Compromise achieved-one set reconstructed
Presenter
Presentation Notes
Standard 6 requires substantiation of missing features that are to be replaced by documentary, physical, or pictorial evidence. In this case, we had several post cards depicting the obelisks and the overlooks (click). The designers considered if rebuilding the obelisks was possible and determined it wasn’t if we were going to rebuild the overlooks. The overlooks were identified by the group as a very important character-defining feature of the structure, and also served a practical function. The proposed lighting has to accommodate pedestrian and vehicular traffic; if the lights were attached to the obelisks, the obelisk placement would differ from the original, obstruct the overlooks, and change in proportion and size. These changes would not be in keeping with the Standards 6 or 9. Another CP suggested a single set of obelisks be added to the Reading end of the bridge, acting as a gateway of sorts into the city. The designers were able to accommodate this compromise.
New Work – Compatible but Differentiated
Standard 9. The new work shall be differentiated from the old and shall be compatible with the massing, size, scale, and architectural features.
SR 78 over Schuylkill River (1955), Hamburg, Berks County
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Presentation Notes
This is the SR 78 bridge over the Schuylkill River (and other resources) between the Borough of Hamburg exit and the exit for Cabela’s/SR 61 in northern Berks County. Originally carried Old Rt. 22. When 78 was constructed, the parapet walls were replaced with safety-shaped barriers, farther narrowing the already slight profile of the road. There is a need for better acceleration lanes at these two interchanges, which affects the width of the bridge. It also needs shoulders, of which it currently has next to none. 44,000 VPD, with 35% heavy truck traffic. It needs to be widened. The need that kept this at a rehabilitation project was that you don’t detour 44,000 vehicles per day. You don’t even take it down to one lane unless there is no other option. District agreed to a creative solution – adjacent structures flanking the original bridge, tied together at the deck and the pier bases. Through CP consultation, we landed on a design that met Standard 9’s requirements – it maintains the scale, size, and massing but is different enough that it could be distinguishable as a later addition. It also has the benefit of, in theory, being reversible.
Lessons Learned
• The Standards are there to help. Use them. Share them with your project team, including the contractor and inspectors.
• Make special provisions work for you. Be specific and thorough.
• Work with Construction to develop enforceable consequences for work that doesn’t meet expectations. Define those expectations in the special provisions and ensure they are reasonable.
• Meet with the contractor and inspectors periodically, even if you don’t have specific work to review.
• A contractor who is held to a standard with consequences will likely give you a good product.
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Presentation Notes
Thank you for your time this morning. Concrete arches are a big part of the built environment in my Districts, and I’m glad I have had the opportunity to be a part of their continued preservation. I’m going to hand it over to Kara Russell who will be talking about the management of another type of structure, truss bridges.
