Discussing current issues in engineering
Concrete has dominated the modern construction industry since the start of its commercial manufacturing in the nineteenth century. Asphalt concrete, a specific variety of concrete used for paving and typically referred to as “asphalt,” gained popularity during this same period. As the foremost option for road construction, asphalt’s popularity rose in conjunction with the commercial automobile industry. Today, concrete is the most commonly used building material in the world, and second only to water as the world’s most widely used substance.
Despite worldwide popularity, concrete and asphalt structures can fall short of their expected lifespans. Modern concrete and asphalt structures are known to deteriorate far faster than their historical counterparts. Deterioration takes many forms: cracks, breakdown into fine particles, interior hollowing, and separation into layers. All forms of deterioration threaten the integrity and safety of structures, translating into decreased lifespans and increased maintenance or replacement costs.
When compared to the endurance of historical concrete, widely studied processes like aggregate expansion, chemical damage, and rebar corrosion (in reinforced structures) present only a partial picture of deterioration root causes for modern concrete structures and asphalt pavements. A paper recently published by the journal PLOS ONE sheds light on one significant additional cause of deterioration.
The paper authors—a team of researchers drawn from six diverse institutional environments (medicine, manufacturing, higher education, and consulting)—began their inquiries with the unexplained odor that emanates from commercial cement when mixed with water. The researchers hypothesized that the odor derived from organic matter. From there, they examined the presence of organic matter in relation to concrete deterioration.
Currently, scientists and inspectors determine deterioration rates through surface crack measurements and a chemical test. This team of researchers used a micro focus CT scanner, like those used in medical settings, to develop cross-sectional images of asphalt and concrete samples. The samples originated from a variety of geographical locations and time periods where unexplained asphalt and concrete damage had occurred. After procurement, researchers exposed the samples to test conditions reproduced from moisture permeation levels calculated in the field. This permeation process enabled the team to accurately represent the real-world relative humidity of summer.
Researchers determined that asphalt and concrete samples contained organic molecules from a variety of sources: phthalates, surfactants, windshield washer fluids, and diesel exhaust particulates. Comparisons between CT scans showed that phthalates, chemicals used to increase the durability of plastics, had the most significant effect on concrete and asphalt deterioration. For the first time, researchers demonstrated that organic matter levels, whether introduced during the production process or real-world exposure, were indicators for the deterioration present in modern concrete and asphalt.
The researchers believe that their findings will contribute to the development of enduring concrete and asphalt materials and structures. To read more about the study and findings, click here.
Engineers use time-tested, evidence-based physical laws to determine how materials will behave in a particular situation. With knowledge of a material’s structural makeup, engineers can calculate the integrity of a design—built or theoretical—to ensure that structures fulfill the functions required of them.
The design innovations of previous decades have led to a rise in the use of composite materials throughout the engineering field. Composite products like concrete, plywood, and fiberglass confront consumers everyday as mainstays of modern design. Composite materials can offer expanded functionalities like increased strength or lightness as compared to their constituent materials. But as the complexity of material resources increases, so too does the complexity of equations required to calculate stresses and strains. Even with the advent of artificial intelligence (AI), up until now, engineers have been forced to code stress and strain equations into networks before AI can generate simulations and solutions.
New research published by Zhenze Yang, Chi-Hua Yu, and Markus Buehler of the Massachusetts Institute of Technology (MIT) reveals a process that can calculate the properties of a material through the use of machine learning and computer vision, rather than the input of differential equations (as is presently required).
Researchers selected a machine learning framework known as a Generative Adversarial Neural Network as the foundation of their AI model. In order to train the network, the team paired images depicting the internal microstructures of various materials under stress with color-coded images of the materials’ stress and strain values. After exposure to thousands of paired images, the network learned to calculate stresses based on the geometry of a material’s structural makeup.
Through extensive testing and AI exposure to additional scenarios, researchers also determined that their network could capture “singularities,” such as developing cracks in concrete, and accurately simulate the force and field changes resulting from such events. Overall, the research reveals a system capable of generating stress and strain calculations with less time, resources, and manpower than any other method known to the field of engineering.
Yang, Yu, and Buehler predict that their approach will lead to faster progressions through the engineering design process. Professionals like architects and materials inspectors will benefit from a tool capable of calculating material integrity with nothing more than a snapshot. In addition, nonexperts will be able to gather materials calculations for small scale and pet projects alike, because a fully trained version of the researchers’ network runs on computers with consumer-grade CPUs (central processing units).
To view Yang, Yu, and Buehler’s recent publication in the journal Science Advances, click here.
Wind accounts for the highest percentage of renewable energy generation in the United States. According to the U.S. Energy Information Administration, 8.4% of all electricity produced in the U.S. is derived from wind energy. In 2020, wind accounted for 43% of renewables-based electricity generation—5% more than hydropower and more than ten times the combined electricity yields of biomass, solar, and geothermal energy.
Electricity-generating wind turbines have occupied scattered spaces in the U.S. electricity landscape since their initial conception in the late nineteenth century. When oil shortages in the 1970s forced a reevaluation of the nation’s energy environment, federally funded research and development brought wind turbines into the mainstream.
Despite more than a century of use, the design of electricity-generating wind turbines has remained relatively unchanged. Now, Spain-based tech startup Vortex Bladeless is refreshing the traditional means of wind energy generation with a wind machine that forgoes the defining characteristics of a turbine.
Vortex’s wind machine is a modular, on-site wind energy generator without blades or rotating parts. The machine is comprised of a cylindrical body surrounding a central support that is anchored to the ground. Its ability to generate energy relies on a principle of fluid dynamics called called vortex shedding.
Vortex shedding occurs when fluids (like water or air) flow past a blunt body, creating alternating vortices at the back of the body that detach to form a “vortex street.” When wind passes through the blunt body, the cylinder oscillates toward the alternating low-pressure vortices and subsequently triggers a coil-and-magnet alternator system attached to the central support. Through this process, wind energy becomes mechanical energy becomes electrical energy. In action, the vortex machine resembles one prong of a struck tuning fork rather than the pinwheel shape of a turbine.
Vortex Bladeless launched initial manufacturing with a first series of Vortex Nano devices measuring in at 85 centimeters tall. The company has plans to manufacture generators in a variety of sizes in order to meet site-specific needs. Next on the list is the Vortex Tacoma: a 2.75-meter-tall generator weighing less than 15 kilograms with the capacity to generate 100w. Product features like variable sizing, a light weight, and a low center of gravity hold promise for the wind machine’s ability to occupy a variety of settings, whether rural hilltops or skyscraper railings.
Click here to read more about electricity generation in the United States. For more on the Vortex Bladeless wind machine, click here.
The Navajo Nation retains the largest land area of any indigenous tribe in the United States. Navajo land spans 27,000 square miles—an area larger than West Virginia—and occupies territory in three states: Arizona, Utah, and New Mexico. More than 173,000 of the 298,000 enrolled Navajo members live on Navajo Nation soil.
According to the Indian Health Service (IHS) and the Navajo Tribal Utility Authority, an estimated twenty to thirty percent of the Nation’s residents do not have access to piped water in their homes. Most occupants of homes without piped water rely on hauled water. In some cases, occupants may rely on bottled water for drinking, cooking, cleaning, and bathing.
The COVID-19 pandemic, which has rocked the Navajo Nation with 30,350 cases to date, exacerbated preexisting strains placed on Navajo communities through insufficient and unreliable water access. To combat these deficits, advocates from a variety of sectors—Navajo Nation and federal officials, nonprofits, universities, utility providers—united to form the Navajo Nation COVID-19 Water Access Coordination Group (WACG) which aims to increase tribal homes’ access to safe, quality drinking water.
Last year, in an effort to further WACG's mission, the Indian Health Service and Navajo Engineering & Construction Authority (with the help of Federal CARES Act funds) installed small hydrants connected to piped water throughout the Navajo Nation, creating 58 new transitional water points available to tribal households. This more than doubled the 48 existing water access points in the Navajo Nation. Furthermore, for the duration of the Navajo Nation COVID-19 Public Health Emergency, CARES Act funds enable the WACG to waive water fees and provide water storage containers and disinfection tablets free of charge.
Funding has equipped the WACG to expand water access in the Navajo Nation during the COVID-19 pandemic, but health, human services, and Native justice advocates continue to search for economically feasible infrastructure expansion solutions that will last beyond the current health crisis. As facilities on tribal lands near the end of their life expectancy, more systems need maintenance and replacement, resulting in high estimated construction costs passed on to consumers who may not be able to afford higher utility costs. Rex Kontz, deputy general manager of the Navajo Tribal Utility, says that when it comes to raising utility rates, “all you’ll get is a bunch of people disconnected for nonpayment.”
While there is still an effort to supply homes with piped water, long term solutions to Navajo water inaccessibility may look different from solutions found in many parts of the United States. Navajo officials and utility providers are considering large water loading stations with high flow rates that could serve more residents than the new water access points. WACG members, including the IHS and Johns Hopkins University, are also assessing tech-based solutions like hydropanels and solar powered filters at wellheads.
For more on the Navajo Nation Water Access Coordination Group, click here. To read more about water access points installed in the Navajo Nation, click here.
President Biden’s recent unveiling of the $2 trillion American Jobs Plan renews emphasis on improvements to underperforming infrastructure. As the U.S. enters warmer months, wildfires and wildfire prevention will resume a chief position among infrastructure concerns.
2020 was the worst wildfire season experienced by America’s western states in 70 years. Thousands of Americans evacuated their homes throughout the season, and residents in and around wildfire-stricken areas endured air quality that ranked among the worst in the world.
Last week, the American Society of Civil Engineers (ASCE) hosted an ASCE Interchange interview with Geoff Coleman, a wildfire resilience expert and the vice president of California-based engineering firm BKF Engineers. Coleman spoke with Interchange’s Casey Dinges on key considerations for the future of wildfire-resilient infrastructure in America.
Coleman stressed the importance of public education on wildfire risks and mitigation strategies in fire-prone areas. He recommended that individuals consider evacuation routes and defensible space—the area around a structure designed to reduce fire danger—in home planning and maintenance, and suggested alternatives to traditional grass yards like rock gardens and drought-resistant, high moisture succulents.
More significantly, Coleman stressed the role that civil engineers and appointed officials must play in limiting community fire risks. When fires take hold of a wildland area, entire communication systems, water supplies, electric grids, and transportation networks are threatened. Coordination among emergency responders can be interrupted through the destruction of remotely located communication towers. Burning plastics and industrial materials may contaminate water that is then drawn back into municipal water supplies. An inability to isolate electric services can lead to mass shutdowns.
In order to diminish these possibilities, engineers and community leaders can focus on increasing defensible space around essential structures like water towers, cell towers, and power stations. Better yet, these essential structures can be located outside of fire-prone areas. Roads should be designed with evacuation, response, and reconstruction in mind: paved with compliant turnarounds, multiple points of egress, and widths in excess of forty feet to enable transportation of sufficient water supplies during a fire event and construction equipment in the aftermath.
Lastly, Coleman stressed the importance of introducing fire safety and prevention early into the design process through the involvement of fire code officials. The combined vigilance of engineers and their communities is required to create infrastructure that prioritizes public safety in wildfire-prone areas.
To view ASCE Interchange’s interview with Geoff Coleman, click here.
Homeowners and renters alike may be familiar with the Federal Emergency Management Administration (FEMA)’s Flood Maps, which provide a visual representation of a community’s flood risk. The National Flood Insurance Program (NFIP), which is managed by FEMA, uses community flood risks gathered from FEMA maps to calculate insurance rates for its more than 5.1 million policyholders—policyholders who, by many accounts, used FEMA flood maps to calculate their potential risk and therefore inform policy-buying decisions in the first place.
Unfortunately, FEMA maps were created to represent risks at a community level, and consequently do not serve as an accurate measure of risk for individual properties. The flood risk research nonprofit First Street Foundation uses modeling techniques to fill in these informational gaps, thereby establishing the first public collection of property-level flood risk data in the United States.
In a 2020 report, First Street Foundation’s team of researchers found that 14.6 million properties across America were characterized by substantial flood risk (a one-percent chance of annual flooding). Millions of these property owners may have been previously unaware of their risk because their properties were located outside of FEMA’s Special Flood Hazard Areas and were therefore excluded from FEMA Flood Maps.
In a study published last month, First Street Foundation noted that some property owners took steps to mitigate potential flood damage in 2020, thereby decreasing the number of residential properties at risk of unmitigated flood-related financial loss to 4.3 million. This decrease shows marked improvement for many properties once at unabated risk. Nonetheless, the February report makes it clear that underestimated flood risk remains a significant financial threat to millions of American households.
The discrepancy between supposed flood risk and actual flood risk is evidenced by substantial difference between premium flood insurance rates and estimated financial costs to properties as a result of flooding events. The average NFIP premium for the 5.7 million American properties with any flood risk is $902, while the average estimated loss for these same properties is $3,343 per year. This means that the current economic risk to 5.7 million properties is 3.7 times higher than the NFIP’s insurance pricing. The disparity continues to grow as sampled data is limited to the 4.3 million properties with substantial flood risk, where the average estimated annual loss of $4,419 is 4.5 times greater than the NFIP’s premium of $981.
The First Street Foundation’s February report highlights the need for increased flood risk awareness among American property owners and increased flood insurance coverage among insurers. As flood events become more widespread and intense due to climate change, America’s number of at-risk properties will continue to rise.
Visit FloodFactor.com to access current flood risk data for 142 million public and private properties. Click here to read the First Street Foundation’s February 2021 report.
Every four years, the American Society of Civil Engineers (ASCE) releases its assessment of the current condition and needs of United States infrastructure. The Report Card for America’s Infrastructure takes the form of a school report card, with grades designated from A to F, as an easily identifiable (and modestly tongue-in-cheek) depiction of where our nation’s infrastructure stands in relation to our public safety, health, economic, and security goals.
This year, America ranked just below average at a C- overall. This is up from a D+ in 2017 and marks the first time that American infrastructure has ranked above the D range in two decades, indicating incremental progress in infrastructure restoration. According to Ruwanka Purasinghe, EIT, A.M.ASCE, a member of the committee that determines the quadrennial grade, “the overall grade of a C- shows that we’re on the right track but have a ways to go.”
The Infrastructure Report Card overall grade is derived from the assessment of seventeen individual categories—aviation, drinking water, energy, public parks, schools, stormwater, and transit, to name a few. Like nearly every other aspect of American societal life, all seventeen categories have faced heightened strain throughout the pandemic as COVID-19 continues to impact revenue streams intended for infrastructure. At the same time, climate change tests the limits of our existing structures and related severe weather events impede potential restoration efforts. Now more than ever, infrastructure networks require attention and investment in order to overcome the obstacles before them.
The ASCE cites three significant trends that contribute to report results for all assessed sectors. Firstly, the society highlights maintenance backlogs, a persistent issue also featured in the 2017 Report Card, as a cause of poor system performance. Nonetheless, the ASCE notes that new technology and appropriate asset management are helping to bridge the gap between limited funds and necessary maintenance. Secondly, in the last four years, federal, state, and local governments have made positive impacts on sectors through financial and human investment. For example, more than 25 major cities and states have now appointed chief resilience officers in order to promote resilience building at the state and local level. Lastly, the ASCE notes that some infrastructure sectors suffer from a scarcity of condition information and reliable data. When it comes to stormwater, for example, a dearth of updated asset records prevents accurate estimations for the lifespans of stormwater conveyance systems across the country.
When the ASCE unveiled the 2021 report at a virtual news conference last week, representatives from all corners of industry and politics voiced the need for bipartisan support on infrastructure investment. With a mounting annual investment gap of nearly $260 billion, America’s infrastructure can wait no longer. Infrastructure shortcomings demand resolutions—our collective economic foundation and quality of life depend on it.
To read the ASCE’s 2021 Report Card for America’s Infrastructure, click here.
As the pandemic continues to draw attention to infrastructure shortcomings all over the globe, engineers and city planners must ask themselves how they can contribute equitable and accessible industry decisions to a post-pandemic world. In an effort to confront this question, California’s Los Angeles County hosted a series of five webinars last year at the Los Angeles Headquarters Association, an organization designed to advance economic growth in the county.
The series ran from July to November and featured a long list of influential panelists including an L.A. City planning commissioner, regional non-profit executive, chief design officer at the L.A. mayor’s office, Lyft senior public policy manager, architects, and designers. Panelists addressed pervasive issues made plainer by the pandemic and our country’s present grappling with institutionalized racism and racial inequality.
Because engineering and design professionals have traditionally held a significant role in land use decision-making, panelists placed a focus on the professional’s duty to address the needs of a community. In the past, engineers have been key players in an approach that tells communities what they will receive without addressing (or even seeking out) the concerns of community residents.
Take, for example, the fact that women, specifically women of color and mothers with children, are more likely to ride the bus than men. Yet bus stops all around the country are essentially designed for the use of 30-year-old white men—individuals who may not be threatened by standing in the dark at night, or in the summer sun for twenty minutes. Furthermore, as discussion moderator Katherine Perez points out, community land-use decisions have often unevenly damaged diverse and low-income neighborhoods. Consider decisions regarding landfill or freeway locations—or any other variety of less-desirable infrastructure for that matter.
Webinar discussions highlighted the power that engineers have to address issues of equity through their creativity and influence on project budgets. As panelist Paul Moore, P.E., of the Arup professional services firm states, “[W]hile policymakers and planners can have fantastic ideas and intentions about how to reshape cities, it’s engineers who are often empowered to implement the ideas.”
The Los Angeles Headquarters Association webinars publicized the role of engineers in inclusive infrastructure. Moving forward, engineers around the world are responsible for the creation of equitable and sustainable value accrual practices through their infrastructure and design projects.
To learn more about the L.A. Headquarters Association webinars and panelists, click here.
EnviroRail Embraces Green Railroad Construction and Maintenance Through Partnership with Mechanical Concrete
The Nebraska-based railroad service contractor EnviroRail recently licensed Mechanical Concrete, an industrial strength aggregate confinement technology, marking a first for the future of sustainable railroad construction and maintenance.
All roads require regular maintenance throughout their lifespans. This is due in part to the fact that most road foundations, including railroad foundations, are comprised of compacted stone aggregate which weakens when wet. As pressure is applied to the wet aggregate particles spread out laterally resulting in a loss of road structure. This process yields features like ruts, potholes, and collapsed road edges. Railroads are particularly susceptible to this form of deterioration because of the high pressure loads typically transported by rail.
Samuel G. Bonasso, P.E., the creator of Mechanical Concrete, realized that in order to slow down this cycle of road deterioration and maintenance he needed to address the structural issue associated with loss of road base structure. His solution was simple: to prevent the loss of road structure, prevent aggregate lateral spread. What’s more, Bonasso incorporated a readily-available, oft-discarded industrial waste product into his process, creating a reliable and sustainable materials sourcing practice.
Each year, more than three hundred million waste auto tires are generated in the United States. And while tire recyclers make use of some eighty percent of waste tires through the recycling process, roughly half of those recycled tires are then burned for tire-derived-fuel. Mechanical Concrete is the first large-scale reuse alternative for discarded tires.
Mechanical Concrete uses waste auto tires to contain stone aggregate, thereby preventing the majority of aggregate lateral spread. Waste tires are stripped of their side walls to create a durable rubber cylinder and then filled with a granular aggregate. The resultant product creates a foundation that is stronger and more dependable than aggregate used in isolation.
In demonstrations hosted by West Virginia University’s School of Engineering, Mechanical Concrete proved three times stronger than traditional road foundations, and ultimately required seventy-five percent less maintenance. The recent contract between EnviroRail, as a nationwide railroad services contractor, and Mechanical Concrete provides encouraging evidence for a new era of railroad maintenance and sustainability.
Click here to learn more about EnviroRail’s contract with Mechanical Concrete. For more information on Mechanical Concrete, visit the company site.
Hospitals have struggled to make space for influxes of COVID-19 patients since early in the pandemic. In counties around the country, continued surges of the virus now affect medical services for any individual who may need care, regardless of whether the individual suffers from COVID-19. Health districts have been forced to respond to diminished ICU bed capacities with creative measures. For New York State’s Long Island region, as for many other areas around the country, these measures have taken the form of temporary field hospitals.
The placid, wooded campuses of Long Island’s Stony Brook University (SBU) and SUNY College at Westbury host two of these temporary hospitals. The structures are hulking, frame-supported tents that add a combined 2,060 beds to the area’s medical network. Each tent is comprised of heavy-gauge vinyl panels that are individually tensioned and bolted to a metal framework.
Prior to construction, engineers faced the difficult task of securing a stormwater control system for projects with two major flooding factors stacked against them. Firstly, the tents would be constructed on poorly drained turf fields and thereby posed a flood risk in the presence of a medium rainfall event. Secondly, the heavy-gauge vinyl material that would ensure a leak-proof final product also made rain cascade faster down the roofs of the tents—in this case, engineers anticipated a maximum rate of 1,230 gallons a minute. If left unchecked, this could accelerate damage to foundations or result in seeping from a structure’s base.
A conventional frame-supported tent utilizes gutters and downspouts to catch and route stormwater. Project engineers needed to take this approach one step further by redirecting stormwater far away from the vulnerable turf. They selected 12-inch double-walled corrugated pipe for its flexibility and local availability. The pipe’s light weight allowed single workers to manipulate and secure large sections at a time, while its flexibility enabled ninety-degree connections aboveground.
Beginning at the field hospital gutter systems, the corrugated pipe bends down and around the tent structures, passing underneath ambulance roadways and eventually into underground swales designed to contain large quantities of runoff and facilitate its percolation. The use of corrugated pipe enabled SBU and SUNY field hospital project engineers to confront flooding factors without sacrificing construction speed or versatility. In both cases, the whole construction process took about three weeks. The hospitals were ready to accept patients in April 2020.
To learn more about stormwater drainage for SBU and SUNY field hospitals, click here. To learn more about the temporary fabric structures frequently used in field hospital designs, click here.
Colman Engineering, PLC
A professional engineering firm located in Harrisonburg, VA