Discussing current issues in engineering
The City of Hampton, Virginia, recently joined a short list of U.S. communities spearheading green infrastructure investment through the use of Environmental Impact Bonds (EIBs).
First developed by D.C.-based social investment firm Quantified Ventures, EIBs are a financing tool that encourages investment in green infrastructure by linking financial returns to measurable performance outcomes. Public utilities issue the bonds alongside performance targets and timeframes, and independent parties assess project success through the achievement of said targets. EIBs can be used to fund pilot approaches to sustainable infrastructure or to scale up lab-tested environmental projects.
The EIB’s outcomes-based financing approach helps to stabilize green infrastructure investments, which can be risky due to the varying efficacies of individual green projects, and thereby increases venture capital opportunities for communities interested in going green. For the City of Hampton, this EIB will equate to approximately $12 million in stormwater-related infrastructure projects with the end goals of reducing pollution and enhancing the city’s resilience to flooding events.
Hampton is bisected by Newmarket Creek, a tributary of the two-mile-long Back River that eventually feeds into the Chesapeake Bay. In recent years, severe weather events and sea level rise have led to the increased flooding of Newmarket Creek. Hampton’s planned green infrastructure projects would combine to expand the stormwater storage capacity of the Newmarket Creek watershed by an excess of 8.6 million gallons. With sea levels and the occurrence of severe weather predicted to continue rising, these projects will provide valuable security against future flooding events while also creating neighborhood assets for Hampton residents.
Project designs include a series of manmade wetlands and detention ponds that combine to form a “stormwater park,” extensive vegetation installations, and an increase in elevation for a major city road. You can learn more about the City of Hampton’s Environmental Impact Bond and green infrastructure projects here.
Research into a new bridge design offers potential relief for the expensive and dangerous threats posed to bridges by seismic events.
Contemporary bridge designs follow a monolithic model: forms are constructed then concrete is poured over the forms, yielding a final structure. These traditional monolithic bridges are strong enough to support their own weight plus additional loads such as traffic but are often damaged by unexpected seismic events like earthquakes.
Restoration to a bridge damaged by seismic activity is a lengthy and expensive process, and the damage itself can result in injuries and loss of life. In recent months, researchers at the University of Colorado Boulder and Texas A&M University set out to evaluate a theoretical bridge design, called the hybrid sliding-rocking (HSR) bridge, that aims to mitigate the issues plaguing traditional bridges as a result of seismic events.
Where a monolithic bridge emphasizes unyielding concrete, an HSR bridge offers columns containing limb-inspired joints that slide and rock to diffuse seismic energy as it travels through the ground. Not only is an HSR bridge more capable of energy dispersal—the uniquely complex sliding-rocking interaction also allows HSR bridges to self-center amidst seismic activity, almost like the adjustments to joint movement made by a person who has achieved “sea legs.”
Researchers at CU Boulder and Texas A&M conducted earthquake simulations on experimental HSR columns and found that the HSR columns sustained less damage when compared to practical evaluations of conventionally designed columns. Damages sustained by the HSR columns also proved relatively quick to fix with common restoration materials.
Although HSR bridge design remains theoretical, with no practical implementation into real world bridges at this time, findings from this latest research study generate optimism for the future of bridge safety and durability amidst seismic activity. You can learn more about the research study conducted by CU Boulder and Texas A&M here.
The American Society of Civil Engineers (ASCE) just released their first-ever Report Card for West Virginia’s infrastructure, giving the state an overall grade of “D”. This grade indicates the state’s infrastructure is in poor condition with new construction and repair efforts unable to keep up with the state’s needs. The report card was also broken down into infrastructure categories giving grades for bridges (D+), dams (D), drinking water (D), roads (D+), and wastewater (D).
The report found that of West Virginia’s 7,291 bridges, 21% are structurally deficient, which is significantly greater than the national average of 7%. Of the 38,854 miles of public roads in West Virginia, 31% are in poor condition compared to 21% nationally. As a result, the ASCE report estimates that it costs $723 per motorist per year from driving on roads in need of repair in West Virginia.
Dams in West Virginia were also rated as poor with 75% of the state’s dams classified as high-hazard potential, indicating failure would result in significant economic loss and loss of life. The state would reportedly need more than $900 million in funding to continue operation, maintenance, and repair of high hazard dams.
Lastly, an estimated $1.39 billion is needed in drinking water infrastructure over the next 20 years with West Virginia currently losing more than 50% of their treated water due to leaks in infrastructure. Significant portions of West Virginia’s wastewater systems have also deteriorated with 59 combined sewer systems needing $1.2 billion in funds to address state and federal requirements.
Some encouraging prospects, however, include the establishment of the West Virginia Roads to Prosperity Program in 2017 that will ultimately invest $2.8 billion in more than 700 road and bridge projects and create over 48,000 jobs. In addition, inter-agency collaborations are expanding access to resources to upgrade drinking water and wastewater infrastructure to meet new quality standards. And overall, it’s important to note that West Virginia’s “D” infrastructure grade is on par with the nation’s overall D+ grade from the most recent 2017 infrastructure report card for the United States. You can read West Virginia’s full ASCE infrastructure report card here.
Converting an Old 178-acre Golf Course for Stormwater Management Near the Texas Coast Completes Phase Two
One of the largest urban stormwater initiatives ever undertaken in the state of Texas recently completed phase two of the five phase project involving the conversion of a 178-acre golf course into detention ponds, natural habitat areas, and recreational trails for the protection of thousands of homes from flooding events.
Located just outside of Houston in Clear Lake City, TX, an out-of-use 178-acre golf course and country club were purchased by Harris County for the purpose of converting the property into a series of five stormwater detention ponds that will protect approximately 2,000 – 3,000 homes from 100-year flood events. Named “Exploration Green” the project completed phase one in 2018 with the construction of a 23.7-acre detention pond, 15.2 acres of natural habitat, and 1.25 miles of recreational trails. When Hurricane Harvey hit in 2018, 80% of the first phase was completed and the detention area held enough stormwater runoff that houses that typically flooded with just 5 to 10 inches of water from storms had no flooding with the 45 inches of rain from Harvey.
With the recent completion of phase two, the project added an additional 26.2-acre detention pond, 18 acres of natural habitat, and 1.3 miles of recreational trails. Together the two ponds provide a 250 acre-ft. storage capacity for flooding with natural areas comprising nearly 3 acres of wetlands, a small island providing bird habitat, and almost 15 acres of planted native grasses. In 2018 the project received an Excellence in Green Infrastructure Award from the U.S. Environmental Protection Agency and National Association of Flood and Stormwater Management Agencies and in 2020 the project was awarded the Engineering Excellence National Recognition Award from the American Council of Engineering Companies.
Ultimately, Exploration Green will consist of 5 detention ponds and 40 acres of wetlands designed to hold 500 million gallons of stormwater and clean the runoff from 95% of the storms that occur in the community. All five phases are expected to be completed by 2022.
ENR’s 2020 MidAtlantic Project of the Year Awarded to a Washington D.C. Innovative Highway Land-Use Project
Engineering News-Record (ENR) announced the 2020 MidAtlantic Best Project of the year was awarded to a project that constructed a seven-acre platform above highway I-395 in northwest Washington D.C., providing 2.2 million sq. ft. of commercial, retail, and open public space, while also creating a new 700,000 sq. ft. below-grade parking garage spanning three city blocks.
The $263.3 million project, “Capitol Crossing”, returned a three-block section of D.C. back into the city’s historic traffic grid by reestablishing an area between E. Street and Massachusetts Avenue near Capitol Hill. The original traffic grid, established by Pierre L’Enfant in 1791, was disrupted by the construction of highway I-395 in the 1960’s, which divided the East End and Capital Hill neighborhoods. I-395 however, was constructed below street level elevation and the contractors for Capital Crossing devised a plan to cover the existing highway with a massive seven-acre platform and restore street-level space.
The project was first awarded Best Project in the highway/bridge category, placing it as a finalist for the overall MidAtlantic Best Project award. Two panels of industry judges reviewed nearly 100 projects based on criteria including the project’s ability to overcome challenges, contribute to the industry and community, safety and construction measures, and design quality. Ultimately, Capitol Crossing was selected the winning project of the year for the MidAtlantic region.
Capital Crossing not only innovatively utilized space, but the project required extensive relocation of utilities including the installation of a new 138-kV high voltage transmission line, relocating a 36-inch water transmission line, excavating 30 ft. below the water table, and using a lift system with hydraulic jacks to move an 1876 Jewish Historical Society synagogue twice.
In addition, the team had to coordinate extensively with the District’s Department of Transportation, the Federal Highway Administration, and other local and federal authorities for the maintenance and evaluation of affected traffic. The project developed a six-phase traffic control plan including a 24-hour traffic simulation model to help evaluate weekday and weekend construction activities.
Overall, the Capitol Crossing team innovatively utilized available land space while improving traffic flow, reviving the historic vision of D.C., and providing commercial, retail, and pedestrian friendly promenade space. You can view complete building plans and layouts of Capitol Crossing at the official website here.
Dedicated as a National Historic Civil Engineering Landmark in Rockfish Gap, VA, the Claudius Crozet Blue Ridge Tunnel conservation project is almost complete after 18 years of restoration efforts.
The Blue Ridge Tunnel was the longest railroad tunnel in North America at the time of its completion in 1858, traversing nearly one mile through the Afton Mountain connecting Nelson and Augusta county. The tunnel was originally built using only hand drills and black powder and allowed efficient travel Westward from the Eastern United States.
With restoration funding provided by state grants and Federal transportation funds, the tunnel will offer 6,000 feet of pedestrian trails for hikers, walkers, and bicyclists while also linking into existing trail systems. Woolpert architecture, engineering, and geospatial firm was contracted in 2006 to provide planning, engineering, and construction plans for the design of the trails and restoration of the tunnel.
Overall, the tunnel is 16 feet wide and 20 feet high with an exposed rock interior and located 500 feet beneath the Rockfish Gap ridge of the Blue Ridge Mountains. In October the restoration of the tunnel won a Construction and Design award by the Coalition for Recreational Trails and in 2015 the project also won the Central Virginia Chapter of WTS International’s Innovative Transportation Solutions Award.
In September, the tunnel was officially dedicated by Virginia Gov. Ralph Northam and while the tunnel and trails are still under active construction, the public can expect the Blue Ridge Tunnel to open at the end of 2020. To learn more about the Claudius Crozet Blue Ridge Tunnel you can visit the Blue Ridge Tunnel Foundation’s website here.
Rapid snowmelt events have the potential to contribute to hazardous flooding in the United States and researchers are hoping to improve the design of infrastructure to withstand increased flooding levels from unseasonable snowmelt.
While snow usually melts gradually as seasons move from winter into spring, unseasonably warm temperatures and rain falls onto snow packs can lead to severe flooding events. This is putting newfound pressures on infrastructure designed to withstand rain precipitation and not additional water from snowmelt. Researchers from NASA’s Goddard Space Flight Center and the University of New Hampshire are hoping to improve current flooding estimates for civil engineers by incorporating snowmelt estimates into precipitation estimates for regions across the United States.
The national standards that civil engineers use to design flood resistant infrastructure (NOAA Atlas 14) exclusively uses liquid precipitation estimates and not water from snowmelt. In order to improve this standard, Eunsang Cho, a postdoctoral researcher at NASA’s Goddard Space Flight Center, and Jennifer Jacobs, a civil engineering professor at the University of New Hampshire, created a map that incorporates snowmelt into current precipitation maps for the continental United States.
Cho and Jacobs developed an estimate of snow water equivalent (SWE) that measures the amount of water contained in snowpack. They combined the SWE measure with NOAA’s precipitation data to provide a more accurate picture of NOAA’s current standard precipitation values.
They discovered that in snow-dominant regions, the incorporation of snowmelt increased total precipitation estimates up to 7.52 inches and nearly 17 inches for 25- and 100- year flood estimates respectively. They also found that 23% of the 44 states for which NOAA provides precipitation data, had higher precipitation values than those provided by NOAA.
Brian Henn, a scientist working on global climate models at Vulcan highlighted the fact that some of the most extreme snow melting events have occurred within the last 10 years, indicating that flooding events from snowmelt are becoming increasingly hazardous, especially when older infrastructure is not designed to withstand increasing flooding events due to precipitation from snow melts.
It is important to note, however, that NOAA Atlas 14 still works for most regions of the country where snowmelt is not a significant concern. But for mountainous regions of the western U.S. that contain heavy snowpack, NOAA values are becoming inadequate for estimating realistic precipitation amounts. Cho and Jacobs hope that their findings can improve current guidelines and further inform civil engineers so they can incorporate larger flooding events into the design of infrastructure. For more info you can read Cho and Jacobs’ complete published research article here.
Boulders Slowing Progress on the Chesapeake Bay Bridge Tunnel Expansion Project Now 2 Years Behind Schedule
Originally slated to be completed in 2022, the construction of a second Chesapeake Bay Bridge Tunnel in Virginia Beach is now officially two years behind schedule with the newest hinderance to timely construction being large granite boulders.
The tunnel expansion project is designed to add two additional tunnels parallel to the two current tunnels in order to end the two-way traffic congestion inside the existing tunnels. Construction of the first new tunnel started in 2017 and is being built under a shipping channel located nearest to Virginia Beach. The project was originally scheduled to be completed in 2022 with a price tag of $756 million. However, after a number of delays, the current projected completion date is 2024 with giant boulders being the newest obstacle.
The granite boulders, as large as 6 feet in diameter and weighing up to 25 tons, help make up two 5.25 acre manmade islands. In order to construct the new 5,700 ft long tunnel, the boulders need to be excavated in order to provide access for a tunnel boring machine (TBM) arriving from Germany this year. The TBM is designed to bore through soft soil, not hard granite boulders. Therefore, the construction contractors must pound steel pilings through the boulders as part of the excavation effort to provide access for the TBM. Mike Crist, the bridge tunnel’s deputy executive director of infrastructure described this process as driving a nail through granite rock.
As a result, construction progress is going much slower than anticipated due to the new boulder debacle and construction on the second parallel tunnel is not expected to begin before 2037. You can find more info on the Chesapeake Bay Bridge Tunnel project and the tunnel boring process here.
Next Milestone Complete for a Major Addition to the Only Railway Bridge Connecting Virginia to Washington D.C.
Virginia and DC transportation officials recently announced that environmental impact assessments have been completed for a proposed railway crossing over the Potomac River. The new metro bridge would ease current traffic congestion and ultimately provide hourly passenger rail service between Richmond and Washington DC.
The bridge plan includes two passenger railroad tracks and a pedestrian bridge built alongside the current 116-year-old Long Bridge Potomac crossing, which has been operating at 98% capacity for decades and is currently the only railroad bridge connecting Virginia to DC.
The new bridge construction would allow for passenger rail service to operate on its own tracks rather than sharing the existing track with freight trains. This means passenger trains could leave and arrive hourly throughout the day between Richmond and DC in addition to easing the current traffic bottleneck for commuter rail operations in Northern Virginia.
Amtrak has pledged $944 million to the project and the VRE Commuter Rail Operating and Capital Fund is allowing the use of tolls from Interstate 66 to help fund the project. Virginia’s contribution is relying on an amendment to the two-year budget that would allow the transportation trust fund to keep road and transit construction projects moving forward.
Secretary of Transportation Shannon Valentine highlighted the fact that this new bridge construction would be opening up rail capacity for the entire Mid-Atlantic by connecting the Northeast and Southeast rail corridors of the U.S. which would allow for exponential growth in freight and commuter rail service throughout Virginia. Valentine further explained that this would expand capacity for the Port of Virginia and connect workers to important employment centers, which would contribute to the economic recovery of COVID-19 and overall growth of the Commonwealth.
With the completion of the environmental impact study, Virginia can begin preliminary engineering for the project with the possibility of Virginia Railway Express trains starting service to and from Baltimore beginning as soon as 2025. You can learn more at the official Long Bridge project website.
Imagine powering up your laptop or phone by simply connecting them to the brick walls of your house.
Researchers at Washington University in St. Louis, Missouri are working to do just that with the successful transformation of every-day red bricks into energy storage devices currently capable of powering LED lights.
Julio M. D’Arcy, assistant professor of chemistry and fellow chemistry department scientists recently published their research highlighting the development of “smart bricks”.
Using the strong porous structure naturally found in bricks, D’Arcy and colleagues pumped gases through these pores, which reacted with the brick’s chemical components, creating a coating called PEDOT. The coating comprised of plastic nanofibers embedded inside the brick acts as a sponge capable of storing and conducting electricity within the brick.
Considering bricks already occupy large amounts of space in the form of walls and buildings, this common building material could be utilized as an additional means to store electricity. For example, when used as electricity storage for solar panels, D’Arcy estimates that 50 smart bricks could power LED lighting for up to five hours from stored electricity.
However, there are some limitations with the initial development of smart brick technology. Similar to traditional batteries, the bricks can store large amounts of energy. But batteries can hold onto the charge of electricity and continually deliver it over long periods of time, while the initial research shows that smart bricks can only sustain the stored electricity for short periods of time.
But with further research and development of smart brick capabilities, there is significant potential for someday optimizing the use of everyday brick walls for powering your everyday devices.
Colman Engineering, PLC
A professional engineering firm located in Harrisonburg, VA