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Bridge-in-a-Backpack

Rigidified FRP Tube Arch Bridges

Advanced Infrastructure Technologies (AIT) is revolutionizing bridge construction through advancements in technology. AIT’s composite bridge system won the 2011 Award for Innovation from the American Society of Civil Engineers. This innovative composite bridge system also known as “Bridge-in-a-Backpack” lowers construction costs, extends structural lifespan up to 100 years, and is a more sustainable alternative to the standard concrete and steel bridge construction.

How it Works...

Phases of an FRP Tube Arch Bridge InstallationThe AIT bridge system uses concrete filled, carbon fiber reinforced polymer (FRP) composite tubes. This advanced carbon fiber composite provides external reinforcement to protect and strengthen the superstructure elements for increased durability and protection from corrosive factors. The composite arches provide three simultaneous functions for the concrete: they serve as stay-in-place forms, external reinforcement, and protective shells against freezing-and-thawing damage. These arches are filled with self-consolidating concrete. Self-consolidating concrete doesn’t require vibration to achieve full consolidation. In addition, since the concrete is contained in the tube no rebar is required for additional reinforcement. Durable composite decking is attached to the arches and fill is compacted on top of the decking. Gravel and road pavement is then applied.

Costs...

Elimination of steel and steel reinforcement immediately increases the life-span of this type of bridge system because it eliminates the potential for corrosion. In addition, the concrete that is used for the arches stays in-cased in the fiber reinforcement, protecting the concrete from exposure to weather conditions as well. This joint free superstructure system will also reduce the required maintenance compared to standard concrete and steel superstructures. Currently the costs of the fiber reinforced polymer material is on the higher end, however the overall construction costs of this type of bridge system have been comparable if not less than standard bridges due to the reduced man-power and use of heavy machinery. The one thing AIT has failed to address is what happens if one of the tubular arches fails or is damaged. Standard roadway maintenance above the arch should be expected, however repairs to the arch system itself haven’t been discussed.

Applications...

Completed FRP Tube Arch BridgeCurrently AIT’s FRP bridge system can be used on single span bridges from 25 feet to 75 feet and multiple span designs exceeding 800 feet. AIT claims there are over 345,000 bridges under 75 feet in length based on the FHWA NBI data which represents 57% of the national inventory.

For more information on costs and applications, or FRP Tube Arch Bridges visit: www.AITBridges.com

Contributed by Steve Lange, PE, Highway & Bridge Sustainable Leader


The Green Gain

Green Parking Lot Model Layout The Environmental Protection Agency’s (EPA) Office of Solid Waste and Emergency Response (OSWER) initiated several pilot projects through their Innovations Pilot Initiative (IPI) to test sustainable / innovative planning and design approaches with the potential to reduce environmental impacts and improve the protection of public health. One OSWER IPI pilot project was based on development of a “green parking lot” with related innovative and sustainable components.

“Green parking lot” is a term used to describe parking lots that may incorporate a variety of environmentally preferred features, including reduced footprint and / or impervious surfaces, use of stormwater best management practices, and use of recycled materials. A non-profit sustainable community development organization located in Arkansas received an OSWER IPI grant award to design and construct a “green parking lot” for the organization’s new corporate office. A first of its kind in Arkansas, this “green parking lot” solution was to serve as a model for sustainable site development practices, focusing on achieving reduced water and air quality impacts.

The Results

The results of this “green parking lot” pilot program are noteworthy including:

  • Reduced nutrient (nitrogen and phosphorus), heavy metals (lead, cadmium, zinc and chromium), and bacterial (fecal coliform) loading to receiving streams
  • Reduced heat island effect / temperature of surface water runoff through the use of concrete paving and paver materials and increased shading provided by additional tree cover
  • Reduced air quality impacts (sulfur dioxide and particulate matter) through use of recycled materials, thereby reducing “upstream” sources of these air emissions
  • Choice of landscape materials and plant density is critically important to achieving water quality and heat island effect improvements

Several software program models are available to determine specific benefits associated with “green parking lots” such as the Long-Term Hydrologic Impact Analysis (L-THIA) and Pavement Life-Cycle Assessment Tool for Environmental and Economic Effects (PaLATE) models. The use of “green parking lots” to reduce adverse water and air quality impacts along with the modeling tools used to quantify these reductions has value to the architectural and engineering community at a project level and to municipal and state government officials at the watershed/macro level.

Considerations

Key considerations for design and planning include:Green Parking Lot

  • Construction cost for the Arkansas “green parking lot” exceeded typical parking lot construction costs due primarily to its demonstration nature; however, until the best management practices incorporated with the Pilot Project are more customary, initial capital costs will likely remain higher than typical parking lot costs.
  • Overall maintenance/operation costs will likely be higher for “green parking lots” given use of porous pavement, additional irrigation requirements, bio-retention swale plantings, and the like.
  • Environmental benefits through use of “green parking lots” include both site-specific and “upstream” considerations; however, significant benefits will be achieved only if this model is expanded to a regional level.
  • Stormwater management through infiltration can reduce the impact upon existing infrastructure; therefore mitigating some of the impacts of development within a watershed.
  • Other project elements, i.e., choice of lighting fixtures (reduced energy consumption), choice of plant materials (reduced irrigation demand), use of recycled materials (reduced “upstream” effect), and the use of constructed wetlands (further water quality improvement), contributed to the project’s environmental benefits, thereby demonstrating that innovative stormwater management practices (infiltration) are not the single most important consideration.

Contributed by Fred Mock, PE, Site/Civil Sustainable Leader


Renewable Energy at Airports

Roof-Mounted Photovoltaic System at Greater Rochester International AirportWith large, relatively flat expanses of obstruction-free land that is otherwise undevelopable, airports can offer an ideal site installation for solar arrays. On-site solar energy generation provides airports with a chance to produce revenue through leases and/or reduce utility costs by generating electricity from renewable sources. Denver International Airport has been one of the nation’s leaders in solar energy generation, with a 2.0 megawatt solar array (operational in 2008) and a 1.6 megawatt solar array (operational in 2010). These facilities are used to power both the airport’s fuel farm and the automated people mover. A third phase is in the planning stages. Solar systems send a clear message to stakeholders that the airport is “being green”.

The FAA recently published the Technical Guidance for Evaluating Selected Solar Technologies on Airports to be used as a reference for airport sponsors evaluating solar projects on airports. The report provides an introduction to solar photovoltaics, site planning issues, regulatory issues, financial issues, and the Federal government’s role in solar development. This report can be found on the FAA's website.

Considerations

Airports must weigh a number of issues when considering construction of a solar energy farm. The FAA approval process is similar to that of any other airport development project and some advance planning is required. For instance, ground-based systems must be constructed in land that is designated for non-aeronautical use on the Airport Layout Plan. Proposed facilities must also be sited so as to not affect NAVAID performance and must not create a glare issue for pilots. As such, the FAA may require a glare study as part of the airspace review process. Standard airspace and NEPA reviews are also required.

Costs & Payback

Ground-Based Solar Arrays at Sullivan County International AirportPayback periods of 40-50 years or more have been an impediment to more widespread adoption of solar energy. More recently, numerous states and the Federal government have begun implementing financial incentives and other measures that can reduce the payback period to less than 10 years in some circumstances. A recent study showed that average installed costs for photovoltaic systems in New York State went from $9250.56 in 2003 to $6890.02 per kilowatt, a 25% reduction. Further reduction in installed costs is expected as technology improves. System efficiency is expected to improve as well.

A Bright Future

The future of photovoltaic technology is “bright”. The combination of improved technology and a dynamic range financial incentives designed increase production of “green” energy means that use of photovoltaics will only increase. Airports offer ideal space to participate in this green energy revolution, and improve their bottom line at the same time.

Contributed by Jeff Wood, CSDP, Aviation Sustainable Leader


Sustainability Tracking, Assessment & Rating System

About the Program

The STARS program is an innovative framework, against which universities can gauge their progress towards sustainability. The Sustainability, Tracking Assessment & Rating System (STARS) program, a program of the Association for the Advancement of Sustainability in Higher Education (AASHE), is an innovative, voluntary self-reporting framework for colleges and universities to gauge progress toward sustainability and be recognized for sustainability leadership. The program is designed to:

  • Provide a guide for advancing sustainability in all sectors of higher education, from education and research to operations and administration.
  • Enable meaningful comparisons over time and across institutions by establishing a common standard of measurement for sustainability in higher education.
  • Create incentives for continual improvements toward sustainability.
  • Facilitate information sharing about higher education sustainability practices and performance.
  • Build a stronger, more diverse campus sustainability community and promote a comprehensive understanding of sustainability that includes its social, economic and environmental dimensions.

Recent Updates

AASHE launched STAR 1.1 on February 9, 2011. The release highlights two fundamental principles of STARS: a belief in a process of continuous improvement and the other of transparency. AASHE offers a downloadable PDF that details the differences between STARS 1.0 and 1.1.

Benefits of STARS Implementation

The use and implementation of STARS and its tools will facilitate the awareness and advancement of sustainability at participating campuses, as well as create program visibility to for students, perspective students, benefactors, faculty, and administration of these institutions.

For more information regarding the program and recent updates, visit: www.aashe.org

Contributed by Bob Lambert, PE, CSDP, Buildings & Facilities Sustainable Leader

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