Environmental News Highlights – November 18, 2020

A roundup of headlines curated for state transportation environmental professionals


AASHTO Transportation Policy Forum Maps out Post-Election Political Landscape – AASHTO Journal

USDOT Transition Team Unveiled by Incoming Biden-Harris Administration – AASHTO Journal

Infrastructure is key to Biden’s climate dreams – E&E News

Congressman Earl Blumenauer bullish on transportation under Biden – BikePortland

No One’s Riding Transit. So Why Did Voters Support It? – Wired (Commentary)


More Than Half of Americans Plan Thanksgiving Travel Despite Pandemic, TripAdvisor Says – WBTS-TV


Regional initiative targets transportation, climate change in underserved rural communities – Daily Hampshire Gazette

Vermont groups urge state to join regional climate/transportation plan – Vermont Business

America’s Forgotten Marine Highway Network That Could Green Global Freight Transport – Forbes

The ‘order of planning’ determines transit priorities. What if we inverted it to prioritize people? – GreenBiz (Commentary)


Mapping air pollution at the neighborhood level – Axios


Chicago’s Mayor Turns City’s Infrastructure Into Weapons Against Protesters – The Appeal (Commentary)


State shares framework for new surface water quality protections – Arizona Public Media

Toll-road plans fall short on wildlife protection, urban sprawl – Orlando Sentinel (Commentary)

Oil pipeline a step closer to approval in Minnesota – Courthouse News

Analysis: Mississippi pump proposal evokes strong reactions – Associated Press


AASHTO Releases Historic Bridge Preservation Guide – AASHTO

Redesigning Slow Streets to reflect community & culture in East Oakland – Smart Growth America (Blog)


Transportation council considers signing on to national bicycle route – KWCC-TV

Cecil Township Taking Pa. Turnpike Commission, Construction Company To Court Over Noise Complaints – KDKA-TV

Can Times Square ever be completely car-free? – 6sqft

Escooter startup Voi uses AI to detect pedestrians and sidewalks – VentureBeat

Northern Kentucky foundation establishes $3M ‘active transportation’ fund – WCPO-TV


State of the Industry Report on Air Quality Emissions from Sustainable Alternative Jet Fuels – ACRP

2021 TRB Annual Meeting: Spotlight Sessions Include Coronavirus (COVID-19), Equity, and the Future of Transportation – TRB

Unfold Podcast, Episode 8: Transitioning to Low-Carbon TransportationUC Davis

[Webinar] The New NEPA Regulations: A Practical Guide to What You Need to KnowJD Supra


Hazardous Materials: Notice of Applications for Modifications to Special Permit – Pipeline and Hazardous Materials Safety Administration (List of applications for modification of special permits)

Hazardous Materials: Notice of Applications for New Special Permits – Pipeline and Hazardous Materials Safety Administration (Notice of actions on special permit applications)

Proposed Information Collection Request; Comment Request; Survey of State Emergency Response Commissions (SERCs) EPA (Notice)

Forest Service Manual (FSM) 3800, Zero Code; State and Private Forestry Landscape Scale Restoration Program – Forest Service (Notice of availability for public comment)

Indefinite Delivery and Indefinite Quantity Contracts for Federal-Aid Construction – FHWA (Interim Final Rule; request for comments)

Jurisdiction in Alaska – National Park Service (Final rule)

Hazardous Materials: Information Collection Activities – Pipeline and Hazardous Materials Safety Administration (Notice and request for comments)

Noise Abatement Part 2: State DOTs Study New Noise Wall Options

State departments of transportation across of the country are looking at new and better ways to predict traffic noise levels, as well new materials for highway sound barriers, in order to reduce the overall cost of noise abatement efforts.

[Photo courtesy of the Missouri Department of Transportation.

This second of a two-part series on state DOT noise abatement strategies examines some of the research state DOTs are conducting to find more cost-effective and innovative designs and materials to mitigate the high levels of roadway noise: everything from using less expensive materials or smaller barriers to designing duel use barriers such as vegetation walls and solar panels.

Traditionally, sound wall barriers are pre-cast or cast-in-place concrete sections. However, several different types of materials have been in use since the beginning of sound barrier construction in the 1960s. The latest noise barrier inventory – maintained by the Federal Highway Administration –indicates barriers constructed with a single material make up 84% percent of all noise barriers. Furthermore: 

  • Concrete comprises 55 percent of those barriers.
  • Block represents 18 percent of those barriers.
  • Wood comprises 5 percent of those barriers.
  • Metal, berm, and brick together account for another 5 percent of single material barriers.
  • “Other” materials comprise the final 1 percent of those barriers, including acrylic, composite, fiberglass, glass, opaque plastic, and transparent plastic.

There are noise walls designed with absorptive material to absorb sound, but the majority are built to deflect sound. Barrier analysis and design must meet the requirements of federal regulation 23 CFR 772 for all federally funded projects.

The Ohio Department of Transportation is in the start-up phase of a research project expected to begin January 2021 to look at the effectiveness of vinyl fence as a noise barrier as opposed to the now-standard concrete barriers.  The project involves constructing two 8-foot tall vinyl fences at two different locations, testing them for noise reductions, and comparing the reductions to nearby concrete noise walls.

Graphic courtesy of the California Department of Transportation

The Ohio DOT plans to use readily available vinyl fence materials that already have specifications available – indeed, one type of fence earmarked for testing is available at the local Home Depot.

Noel Alcala, the noise and air quality coordinator at the Ohio Department of Transportation and noise workgroup coordinator on behalf of the American Association of State Highway and Transportation Officials, explained in an interview that while vinyl is a lot less durable overall than concrete, it is “a lot less expensive and we have an indication that the noise reduction will be very noticeable.”

The Ohio DOT is also studying the feasibility of using vegetation growing on noise walls as both a sound absorber and an air quality improvement and plans to complete a report on that effort by the end of 2020. That effort – based on research conducted in 2010 – looked at a 400-foot long section of “green noise wall.” That wall consisted of a 12-foot-high section of stacked, 70-pound bags sprouting plants and grass as a way to muffle highway sound.

Trees and shrubs can decrease highway-traffic noise levels if high enough, wide enough, and dense enough, but it would take at least 100 feet of dense vegetation to provide the same benefit as the smallest feasible noise wall. Because of this, the FHWA has not approved using vegetation for noise abatement. 

However, future studies could show more innovative choices will result in higher levels of noise absorption. For instance, environmentally friendly and sustainable bamboo growth may provide the needed noise level abatement to meet FHWA requirements. One feasibility study presented at the 2016 International Congress and Exposition on Noise Control Engineering indicated that the noise-reducing effect of a bamboo barrier with a height of 5 meters (roughly 16 feet) and a thickness of 6 meters (nearly 20-feet) is roughly comparable to a 3-meter (nearly 10-foot) high solid noise wall.

Some states are looking to try new noise barriers with a dual purpose. In 2018, for example, the Minnesota Department of Transportation completed a literature review, Harnessing Solar Energy through Noise Barriers and Structural Snow Fencing, on the topic.

That study found that sound barriers equipped with solar panels are used successfully in Europe, though there are no current in-place solar panel noise barriers in the United States. However, two states, Massachusetts and Georgia, are currently working with partners to pursue pilot studies using solar panels built into sound walls so they can produce renewable energy without compromising their abilities to reduce noise – and do so safely. Given the number of miles of sound barrier currently constructed in the United States – over 3,000 miles total – the study found the potential for energy production could be at least 400 Gigawatt hours annually, roughly equivalent to the annual electricity use of 37,000 homes.

The California Department of Transportation is also looking at innovative designs to save money on noise abatement construction.

Currently, Caltrans is exploring the feasibility and effectiveness of lower height barriers and berms. Its latest research suggests that at freeway speed, most all light-vehicle noise is at the tire/pavement interface — literally at the zero-foot level. Meanwhile, on most heavy trucks — even with tall exhaust stacks – most noise is below 3.3-foot level.

That means shorter less-expensive noise barriers would help attenuate noise. A low vehicle noise source also means a short (4-foot) solid-concrete safety-barrier could provide noticeable noise mitigation if positioned correctly in the road cross-section. Shorter barriers mean lower overall costs. State transportation agencies across the United States are making strides to protect the public from high levels of traffic noise. Click here for a list of current state DOT noise reduction projects.

Florida DOT Gearing Up for Statewide EV Adoption

Although Florida trails other big states in government support for electric vehicle infrastructure, the Florida Department of Transportation is now taking a lead role in building out an EV recharging network, according to a new report.

[Photo courtesy of the Florida Governor’s Office.]

The Southern Alliance for Clean Energy and Atlas Public Policy recently published “Transportation Electrification in Florida,” a brief that makes the case that Florida’s government has not kept pace with its own citizens in transitioning to EV transportation. Floridians purchase 4 percent of all EVs in the country, but Florida’s government only spent $23.3 million on EV infrastructure, representing about 1 percent of all states’ spending, according to the report.

This has put Florida is in a “really unique situation” because it is second in the country in EV sales and number of chargers, but only 18th in per-capita sales and 30th in per capita chargers, according to Stan Cross, Electric Transportation Policy Director for SACE.

“What that means is that Florida runs the risk in getting behind in charging really quickly,” Cross said. “If numbers [of EV buyers] go up quickly, Florida can’t keep up.”

However, the Florida DOT is not only playing catch up, it is working to get ahead of the curve with a stated goal to “position Florida as a national leader in EV adoption and infrastructure,” according to a presentation to other agencies and stakeholders.

As a result, the agency is developing an EV charging infrastructure master plan for the state and preparing legislative initiatives to encourage even more EV usage. These actions were the result of the new Florida Essential Infrastructure Law that puts the Florida DOT and other state agencies in the EV business.

Right now, the agency is modeling location criteria for EV charging sites, formulating an implementation strategy, and forecasting future EV usage and its impact to the state’s Transportation Trust Fund – largely fueled by gasoline and diesel taxes. Florida DOT’s effort is comprehensive, including support of EV transit and school bus fleets and integration with hurricane and disaster evacuation plans.

“The [Florida] DOT is thinking through what some of the policy implications are for moving the needle, the principles that should drive the state’s thinking on this,” Cross said. “[They] have a lot to figure out, and they’ve put many of the right policy recommendations on the table.”

In a recent blog, Cross noted that many of the policies the Florida DOT is studying “are aligned with policy considerations being implemented successfully” in other states, including promoting EV usage throughout the state, supporting rural infrastructure development and study incentives to potential EV buyers and to utility companies to help build charging stations. Most of Florida DOT’s work is in the planning stages as it prepares to issue a status report with preliminary recommendations to the governor by December 1.

Environmental News Highlights – November 11, 2020

A roundup of headlines curated for state transportation environmental professionals


Key House transportation figures win reelection – Trains

Biden to Move Fast to Strike Down Trump’s Environmental Agenda – Bloomberg Law

Public transit emerges a big winner in election – Marketplace

President Biden Promises To Boost Transit And Build For Bicyclists But Won’t Tackle Car DependencyForbes (Op-ed)


Supporting healthy urban transport and mobility in the context of COVID-19 – World Health Organization (Report)

Ontario allocates roughly $1 billion for COVID-19 resilience projects – REMI Network


Video: How State DOTs Work to Ensure NEPA Compliance – AASHTO Journal


AASHTO’s ETAP Podcast: Georgia DOT’s Innovative PEL Study – AASHTO’s ETAP Podcast

USDOT loan to aid rural California infrastructure project – Transportation Today

Proposition B: Austin approves $460M in transportation infrastructure bonds – KVUE-TV

Unmanned Aerial Systems Support Flood Management Activities – Innovator (FHWA)

What we’re voting for: infrastructure – The Verge (Commentary)


Why IKEA is investing in sustainable mobility – GreenBiz

Port of L.A. seeks input on zero-emission technology from private companies – City News Service


How one San Diegan uses his bicycle obsession to make the sport more inclusive and accessible to others – San Diego Union-Tribune

Hurricane Relief Through Mutual Aid – Yes!

National E-Mobility Equity Virtual Conference – Forth Mobility Fund (Blog)


If Florida takes over permitting, its life-giving wetlands will be lost to development – Miami Herald (Opinion)

It’s not too late to protect Northern New Mexico – Santa Fe New Mexican (Op-ed)


Parks Canada to create expert panel to advise on a long-term framework for how visitors will get around the Bow Valley and experience Banff National Park in the future – Parks Canada (Press release)


State DOTs Issue Transportation Alternatives & Trail Grants – AASHTO Journal

The Capital of Sprawl Gets a Radically Car-Free Neighborhood – New York Times

Bike Shortages Will Likely Last Until Next Year, and Possibly into 2022 – Bicycling

Boulder talks transportation: Future of bike share, which wheels go where – Boulder Beat (Blog)


(Date Correction) TRB Webinar: Planning an Effective Airport Deicing Runoff Management Program – TRB

Improving Mid-Term, Intermediate, and Long-Range Cost Forecasting for State Transportation Agencies – NCHRP

Improving Mid-Term, Intermediate, and Long-Range Cost Forecasting: Guidebook for State Transportation Agencies – NCHRP

TRB Webinar: Rail in the Time of Coronavirus – Planning, Operating, & Constructing Rail – TRB

TRB Webinar: Cross-Cutting Issues in Urban Congestion Pricing – TRB

Webinar – Protecting Traffic Infrastructure with Weigh In Motion (WIM) – CS2SMART (Link to registration)

2020 Moving Together Conference – UMass Transportation Center


Deepwater Port License Application: Blue Marlin Offshore Port, LLC (BMOP) – Maritime Administration (Notice of intent; Notice of virtual public meeting; Request for comments)

Pictured Rocks National Lakeshore; Snowmobiles – National Park Service (Proposed rule)

Noise Abatement Part 1: State DOTs Developing New Analytical Tools

State departments of transportation across of the country are looking at new and better ways to predict traffic noise levels, as well new materials for highway sound barriers, in order to reduce the overall cost of noise abatement efforts.

[Photo courtesy of the Ohio Department of Transportation.]

The first article of this two-part series will examine some of the new tools state DOTs are developing to better gauge the impact of noise on communities near transportation infrastructure such as highways. 

First, some background: According to the noise barrier inventory maintained by the Federal Highway Administration, more than 3,000 linear miles of noise wall barriers have been built since the 1970s across the United States.

Such sound barriers remain an essential part of highway design and construction as the World Health Organization determined that prolonged exposure to high levels of noise “interferes with people’s daily activities … disturbs sleep, causes cardiovascular and psychophysiological effects, reduces performance and provokes annoyance responses and changes in social behavior.”

Photo courtesy of the Iowa Department of Transportation

The Noise Pollution and Abatement Act of 1972 requires state departments of transportation to monitor and manage highway traffic noise generated by federally funded projects on existing and planned roadways. When that sound exceeds certain thresholds, 23 CFR 772 specifies mitigation efforts must be undertaken to reduce highway traffic noise.

Yet the cost of meeting those regulations and protecting the public against the roar of the vehicles — the predominant sound for both cars and trucks is that of tire-pavement interaction – takes considerable funding.

For example, between 2014 and 2016, FHWA found that total construction costs for noise barriers topped $671 million in just a three-year period – an average of $2 million per mile of noise wall.

That’s why many state DOTs are trying to find ways to reduce the cost of noise abatement efforts, noted Noel Alcala.

“The main goal of more accurate noise abatement modeling can result in cost reduction,” explained Alcala, the noise and air quality coordinator at the Ohio Department of Transportation and noise work group coordinator on behalf of the American Association of State Highway and Transportation Officials, in an interview. “Modeling noise levels more accurately can likely reduce costs noise wall in construction.”

States currently use the FHWA Traffic Noise Model 2.5 to predict noise levels that will occur once a road is built or expanded – even if that expansion occurs several decades in the future.

That complex formula includes the mixture of cars and trucks expected on the road; the buildings and vegetation in the area that would block some sound; the configuration and ground quality of the land between the road and the homes; the ways the sound is expected to diffract around the wall; and other key factors.  Other weather factors can also play a role, such as wind direction and ground and air temperatures. Also considered is the height where the noise is actually originating – at roadway level or top of truck stacks. 

Courtesy of Caltrans

The overall goal of some states, such as California – which sports over 750 miles of highway sound walls – is lowering the noise level at the transportation infrastructure source – a far-cheaper effort than blocking the noise with a more expensive sound wall. 

To that end, the California Department of Transportation has worked over the last few years to implement the most recent National Cooperative Highway Research Program or NCHRP findings into newer modeling techniques.

Caltrans relied on documents such as NCHRP Report 635Acoustic Beamforming: Mapping Sources of Truck Noise, which experimentally validated a practical acoustic “beamforming” measurement technique.

“Beamforming” uses a type of camera that takes pictures (or video) of soundwaves and illustrates that very little acoustic energy comes from tall truck exhaust stacks. Meanwhile, it shows that most highway noise is tire/pavement related and usually occurs very close to the pavement.

NCHRP Project 1-44, reported in NCHRP Report 630, also proved valuable to Caltrans efforts as it proposing a test method for measuring tire-pavement noise at the source using the on-board sound intensity (OBSI) method.

The agency also is implementing AASHTO T 360-16 (2020) – the Standard Method of Test for Measurement of Tire/Pavement Noise Using the On-Board Sound Intensity (OBSI) Method – to reevaluate noise modeling efforts and improve modeling to provide more accurate results. Caltrans has also moved to use more precise noise measurement processes, which it believes will lead to lower community noise levels.

“The AASHTO Standard which precisely measures pavement acoustics, allowed a lot of this work to be accomplished, explained Bruce Rymer, senior engineer in the Hazardous Waste, Air, Noise, & Paleontology Office within Caltrans.

“Using this new measurement technology, we found pavement acoustics had a much larger influence on roadside noise levels than previously acknowledged,” he said, “This is important for state DOTs because noise impacts of transportation projects on roadside communities have to be quantified and analyzed in order to receive federal funding.”

Other states are looking at ways to more accurately predict the costs of sound mitigation as well – now and in the future.

Iowa, for example, is looking at developing a new noise wall cost GIS-based prediction tool that incorporates residential lot information while ensuring that projects requiring noise abatement are properly planned and funded.

Charles Bernhard, Iowa DOT’s Traffic Noise Engineer, said those new processes include five distinct efforts:

Mapping out five-year highway project plans.

  • Eliminating highway projects that do not have an annual average daily traffic or AADT of greater than 10,000.
  • Eliminating projects by “work type” that do not meet the definition of a Type I project for noise
  • Creating a “parcel layer” that includes all residential parcels within 200 feet of the “edge of pavement” of the remaining highway segments.
  • Visually evaluate each remaining highway segment to determine if the segment has a “cluster” of seven or more residential parcels within the 200-foot “buffer.” 

Part 2 of this noise abatement series will examine some of the new types of sound wall materials some state DOTs are studying.

Video: Virginia DOT Uncovers Spooky Artifact During Highway Dig

The Virginia Department of Transportation recently made a major historical discovery at an old Civil War fort uncovered in the median of Interstate 64 near Williamsburg: A “witch bottle.” The superstition surrounding this rare artifact dates back hundreds of years to 17th century England when such “counter magical devices” served as “protection” against witchcraft and evocation.

[Photo courtesy of the Virginia Department of Transportation.]

Environmental News Highlights – November 4, 2020

A roundup of headlines curated for state transportation environmental professionals


The gas tax was already broken. The pandemic could end it. – Smart Cities Dive

What a Senate flip means for transportation – Politico

One-on-one with U.S. Transportation Secretary Elaine Chao – WAOW-TV

Republicans ready to restart critical infrastructure initiative in 2021 – The Hill (Commentary)

Climate Policymaking in the Shadow of the Supreme Court – Resources Magazine

Lawmakers say infrastructure efforts are falling victim to deepening partisan divide – The Hill


COVID-19 Creating Winter Challenges for State DOTs – AASHTO Journal

Two Reports Offer COVID-19 Transit Recovery Advice – AASHTO Journal

How COVID is paving the way for participatory transit planning – Grist (Commentary)

Economic Consequences of Proposed Pandemic-Related Cutbacks in MTA Transportation Services and Capital Spending – NYU Rudin Center for Transportation


What has four years of President Donald Trump meant for Florida’s environment? – Tampa Bay Times

Former Walmart exec brings ride-share technology to fresh produce transport – Green Biz

Eyes Will Be on Biden to Act Fast on Resilience for NYC – City Limits

Amsterdam will use flowers to keep its bridges clear of locked bicycles – Lonely Planet

Virginia breaks ground on largest infrastructure project in state history – InsideNoVa

Will ‘game-changing’ new runway quiet O’Hare jet noise conundrum? – Daily Herald


GM, Ford knew about climate change 50 years ago – E&E News

Trump administration funds projects to more efficiently charge and deploy electric buses – Utility Dive


How infrastructure improvements can aid inclusive revival – CT Mirror


Clean Water Act rollbacks hurt rivers and drinking water – Baltimore Sun (Commentary)

Moose deaths don’t sway WYDOT on 390 speed – Jackson Hole News & Guide

City plans to reduce sewage discharges into region’s rivers. – Pittsburgh Post-Gazette

Oregon DOT begins cleanup from wildfires along state highways and private properties – KTVL-TV


What’s behind Virginia’s increasing pedestrian death toll and how to reverse the trend – Virginia Mercury

More streets added to Montgomery County’s ‘Shared Street’ program for pedestrians – WDVM-TV

California Gets an A Grade in Surfrider’s Annual Beach Report – San Clemente Times

Can the Bike Boom Keep Going? – CityLab

Gov. Justice awards over $1.6 million in Transportation Alternatives and Recreational Trails Program grants benefitting Metro Valley region – WV Office of the Governor (Press release)


Transportation Research Record (TRR) Special Issue on COVID-19: Deadline October 31 – TRB

TRB Webinar: Celebrating TRB’s Centennial by Exploring the Future of Transportation Research – TRB

TRB Webinar: Planning an Effective Airport Deicing Runoff Management Program – TRB

AASHTO to Examine Election Impact on Transportation at Annual Meeting – AASHTO Journal


Information Collection: Interagency Generic Clearance for Federal Land Management Agencies Collaborative Visitor Feedback Surveys on Recreation and Transportation Related Programs and Systems – Forest Service (Notice; request for comment)

NPDES Electronic Reporting Rule— Phase 2 Extension – EPA (Final Rule)

National Wildlife Refuge System; Use of Electric Bicycles – Fish and Wildlife Service (Final rule)

Iowa DOT Studies Erosion, Sediment Control Techniques

To determine the effectiveness of its erosion- and sediment-control techniques, the Iowa Department of Transportation recently teamed up with Iowa State University over two construction seasons to establish which ones worked the best and which ones needed improvement.

[Photo courtesy of Iowa Department of Transportation.]

According to an Iowa DOT blog post, Melissa Serio with the agency’s construction and materials group teamed up with Mike Perez, an Iowa State researcher, to examine alternative erosion and sediment control techniques and adaptations used successfully by other transportation agencies to see how well the Iowa DOT’s standard practices.

Some of Iowa DOT’s frequently used erosion and sediment control techniques include: fabric silt fences to slow water flow and collect sediment; porous mesh tubes (called wattles) filled with straw or other material to control storm water flow; sediment basins or small retention ponds to hold water until solid materials can settle; and rock check dams.

“While we were convinced these elements help control erosion and sediment, it wasn’t clear whether these were the most effective or whether there were other approaches that could be undertaken to achieve better or less expensive results,” Serio explained. “It was important to understand the feasibility of possible changes to practice and identify the right improvements that could be put in place at the right price.”

Photo courtesy of Iowa DOT

While some of Iowa’s existing techniques already performed well, several potential improvements became apparent over the course of the two-year study. For example, simple adjustments to silt fences included reducing the space between posts, adding wire support to the fence’s fabric backing, and cutting a notch, or weir, at the top of the fence so that overtopping of water could be directed to the most desired location.

The Iowa DOT detailed that and other improvements in its final report and technology transfer summary.

Even as the research pointed to potential new best practices, the Iowa DOT said this study “also challenged our expectations.” For example, sediment basins appeared not to be as effective a sediment control measure as had been previously thought. In fact, some data collected suggested that water leaving the basins might have more sediment than it had when entering.

“Further research in a controlled environment will provide more insight, but these initial findings are extremely valuable as we seek to maximize the effectiveness of our erosion and sediment control measures,” the agency noted. “We plan to include the most effective and cost-efficient erosion and sediment control treatments identified in this research project as part of standard road plans in the near future – mostly likely beginning the spring of 2021,” the Iowa DOT said.

Universities Join Forces to Test Resiliency of Bridge Design

In a study published in the Journal of Structural Engineering, Texas A&M University and the University of Colorado-Boulder researchers have conducted a comprehensive damage and repair assessment of a still-to-be-implemented bridge design using a panel of experts from academia and industry. The researchers said the expert feedback method offers a “unique and robust” technique for evaluating the feasibility of bridge designs that are still at an early research and development phase.

[Photo courtesy of Texas A&M University.]

“Bridges, particularly those in high-seismic regions, are vulnerable to damage and will need repairs at some point,” explained Dr. Petros Sideris, assistant professor in Texas A&M’s Zachry Department of Civil and Environmental Engineering, in a blog post.

“Now the question is what kind of repairs should be used for different types and levels of damage, what will be the cost of these repairs and how long will the repairs take — these are all unknowns for new bridge designs,” he added. “We have answered these questions for a novel bridge design using an approach that is seldomly used in structural engineering.”

Most bridges are monolithic systems made of concrete poured over forms that give the bridges their shape: a design strong enough to support their own weight and other loads, such as vehicle traffic. However, Sideris said if there is an unexpected occurrence of seismic activity, such structures could crack and remedying that damage would be exorbitantly expensive.

To overcome such shortcomings, Sideris and his team – with funding from the National Science Foundation – developed a new design called a hybrid sliding-rocking bridge. Instead of a monolithic design, these “sliding rocking” bridges are made of columns containing limb-inspired joints and segments. Hence, in the event of an earthquake, the joints allow some of the energy from the ground motion to diffuse while the segments move slightly, sliding over one another rather than bending or cracking.

Yet despite potential benefits of this design, no data existed about how it would behave in real-world situations. That is where the new testing procedure developed by Texas A&M and the University of Colorado-Boulder comes into play.

“To find the correct repair strategy, we need to know what the damages look like,” Sideris said. “Our bridge design is relatively new and so there is little scientific literature that we could refer to. And so, we took an unconventional approach to fill our gap in knowledge by recruiting a panel of experts in bridge damage and repair.”

Sideris, Dr. Abbie Liel at the University of Colorado-Boulder, and their respective research teams recruited a panel of eight experts from industry and academia to determine the damage states in experimentally tested hybrid sliding-rocking segment designed columns. Based on their evaluations of the observed damage, the panel provided repair strategies and estimated costs for repair.

The researchers then used that information to fix the broken columns, retested the columns under the same initial damage-causing conditions and compared the repaired column’s behavior to that of the original column through computational investigations.

The panel found that columns built with their design sustained less damage overall compared to bridges built with conventional designs. In fact, the columns showed very little damage even when subject to motions reminiscent of a powerful once-in-a-few-thousand-years earthquake. Furthermore, the damage could be repaired relatively quickly with grout and carbon fibers, suggesting that no special strategy was required for restoration. “Fixing bridges is a slow process and costs a significant amount of money, which then indirectly affects the community,” explained Sideris. “Novel bridge designs that may have a bigger initial cost for construction can be more beneficial in the long run because they are sturdier. The money saved can then be used for helping the community rather than repairing infrastructure.”

ETAP Podcast: Georgia DOT’s Innovative PEL Study

In this episode of the Environmental Technical Assistance Program or ETAP Podcast, Jannine Miller and Charles Robinson from the Georgia Department of Transportation discuss the agency’s I-85 Corridor Study and how the department is using a new tool as part of that work: Planning and Environmental Linkages or PELs.

Miller and Robinson explain that PELs represents a collaborative and integrated approach to transportation decision-making that considers environmental, community, and economic goals early in the transportation planning process, while using the information, analysis, and products developed during planning to inform the environmental review process required for transportation projects.

The benefits of PRLs, they emphasize, are improved relationships with stakeholders, improved project delivery timelines, and better transportation programs and projects. To listen to this ETAP Podcast, click here.