Tag Archives: public projects

As goes the asphalt, so goes the nation?

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Two recent paving projects featured in the April edition of Roads & Bridges magazine tell the tale of a new, greener future for civil engineering specifications relating to asphalt projects.

  •  The use of recycled asphalt shingles (RAS) is gaining speed after a test in King County, Washington, where a 2 mile long stretch of roadway was overlaid with a 2-in.-thick layer of hot-mix asphalt (HMA) containing both reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS). The goal was to show that the addition of the shingles to the HMA had no significant negative impact on pavement performance, and the early testing seems to bear that out.

Locally, North Carolina (NC) has a standard specification that allows RAS from manufacturers’ scrap only. The regulations on RAS for other states can be found here.

recycled asphalt shingles

  • The use of a new Re-HEAT process in Greenville, Mississippi enabled the city to repair over 43 streets (versus the 20 streets originally planned). The Re-Heat process, which is an on-site, in-place pavement rehabilitation method that consists of heating existing pavement, removing surface asphalt, adding a polymer-modified asphalt-rejuvenating emulsion, and re-laying the recycled material, followed by conventional compaction. In addition to cost savings, the Re-HEAT process was faster and had an 80% smaller carbon footprint.

A win-win? Are these green projects which can save the greenbacks?

It is, assuming all goes as planned. Or, it can be a win, assuming all parties are aware of, and have given informed consent to, the risks associated with the use of experimental or new construction methods and products.

The lawyer in me can’t help but see potential litigation issues.   With some careful crafting of the construction documents and contracts, however, it can indeed be a win for all involved.  What are your reactions?  Have you specified or used RAS or a re-HEAT process?  Share your thoughts below.

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Photo:  D4647_CM032 via MoDOT/Creative Commons license.

Energy Inc. Conference: the Future of Energy (Tue Tip)

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alternative energy towersDid you know that North Carolina is one of the top nuclear power producers in the country, and also one of the top states in electricity consumption?  North Carolina also ranks among the top 10 states in wind power capacity (pdf).

If you are interested in the future of energy, come on out on for a breakfast seminar entitled “Energy Inc.””

Topics will include:

  1. How will alternative energies such as solar, wind, & water shape the future?
  2. What is the future landscape of collaboration between energy companies?
  3. How will energy laws change energy production/consumption in the future?
  4. How will the state’s energy change as a result of the  Duke Energy/Progress Energy merger ?

 

Panelists: 

Location: 

Cree LED Lighting,635 Davis Drive Ste. 100, Morrisville, NNC 27560

Date: 

Thursday, June 23, 2011

Time: 

7:30 AM          Registration & continental breakfast

8:00-10:00 AM:         Program

Are you interested in energy issues?  What do you think of the Duke Energy and Progress Energy merger?  Alternative energy issues?  Drop me a comment and share your thoughts! 

Photo:  (c) Freefoto.com.

Micropiles for bad soil: a Tar Heel victory

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Kenan constructionDespite foundation challenges, construction is almost complete on the expansion at University of North Carolina’s Kenan stadium.  The project started with a deep foundation system from design-build contractor GeoStructures.  Known as the Carolina Student-Athlete Center for Excellence, the addition was built on a parcel with a knotty mix of fill soils, subsurface boulders and varying depths to rock.   To achieve uniform foundation support, GeoStructures designed a Micropile system (also known as a Mini pile system) which could be drilled into the variable ground conditions.

After an pre-production load testing program that provided an optimized design, GeoStructures proceeded with installation of 265 micropiles ranging in capacity from 80 tons (160 kips) to 175 tons (350 kips) each. Although most were designed for compression loading only, designs in some areas called for tension resistance due to lateral loading. All of the micropiles were cased to rock with internal reinforcement and socketed into hard bedrock present at the site.

For a video peek into the various construction phases, check out UNC’s  “Hard Hat Hits”.

Do you have experience wiht micropile systems?  Foundation or soil tales of woe?  Just love the Tarheels?  Drop me a note in the comments section, below.

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Photo (c) GeoStructures 

 

Wind Power: It’s in the air!

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wind power turbinesWind Power.  It’s been defined as green, clean, sustainable, and even affordable.  In an effort to be more “green,” save or even generate money, and reduce waste, several companies are turning to the wind turbine.

In Indiana, Purdue University and its commercial partner Performance Services have planned and designed a  $200 million wind farm scheduled to begin generating electric power by late 2012.  Earlier this week, the University gave approval to proceed with the project, which will involve obtaining regulatory approval.  If the project is approved, the team hopes to generate 100 megawatts, which could power up to 25,000 homes.

In Canada, Greengate Power Corp. just this week  has received provincial approval from the Alberta Utilities Commission to build Canada’s largest wind farm in southern Alberta.  The project  is expected to be Canada’s largest operating wind energy project with a total generating capacity of 300 megawatts when it is completed.

Also this week, in a town outside of Boston, the local Conservation Commission has approved a wind turbine project, despite objections from the local golf club.

Closer to home, Iberdrola Renewables earlier this year filed an application with the North Carolina Utilities Commission to build what would be the state’s first commercial wind farm in Pasquotank and Perquimans counties.  If approved, the project would occupy approximately 20,000 acres of private land near Elizabeth City, and could potentially provide electricity for 55,000 to 70,000 North Carolina homes.  Construction of the structure, if approved, is slated to begin by the end of this year and could create about 400 jobs.

Share your thoughts:

What is your opinion of wind turbines? Do they make sense?  Is the return on investment worth the additional upfront costs? Do you just plain think they are ugly and not want them in your backyard, or do you see them as modern art and things of beauty?  Drop me a comment!

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Photo:  FreeFoto.com

Bayonne Bridge: Herculean Engineering Effort (Tue Tip)

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Map of Bayonne (Click on image to enlarge)

 Incredible feets of engineering are being planned for at the $1 billion-dollar Bayonne Bridge height raising project,  a project of the Port Authority of New York and New Jersey.  Engineers plan to raise the road from 151 to 215 feet above the Kill van Kull while simultaneously keeping the bridge open to traffic, a measure some are calling  “a Herculean feat of engineering and construction.”  The project is required to accommodate larger container ships (especially those arriving after the widening of the Panama Canal in 2014) to ensure continued viability of the port industry, and raising of the roadbed is the quickest and cheapest solution to the clearance issue. 

“It’s truly an exciting engineering project, by all means,” said Peter Zipf, the Port Authority’s chief engineer. “It’s a completely challenging project, and that’s an engineer’s delight. It’s coming up with a regional solution to a regional need.”   As an engineering precedent, Zipf said the Bayonne project will be the first time a replacement roadbed is constructed above the old one, with traffic remaining open, before the original structure is removed.

bridge construction rendering (Click on image to enlarge)

According to nj.com, during construction, the two inner lanes will be closed to traffic and used as a staging area where a crane will likely be used to hoist a series of 84-foot-wide girders into place, forming the steel structure underpinning the new roadway. Like the original, the new roadbed will be suspended by steel cables from the bridge’s original 79-year-old arch.  The two existing outer lanes will remain open, shielded from the work overhead, providing one traffic lane in each direction. To rise to the level of the higher roadbed, Zipf said the bridge approaches will be made slightly steeper and longer, constructed in a similar method from staging areas on the original approaches.

About the Bridge

When the $13 million Bayonne Bridge opened on November 15, 1931, at 1,675 feet it had become the longest steel-arch bridge in the world, an honor it held for the next 45 years.

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Thoughts on the engineering task ahead of them in maintaining traffic while raising the bridge?  Thoughts on possible legal implications should the project not go as planned?  Sign up for email delivery of the Blog’s posts to your inbox to learn the latest news concerning architects, engineers, designers, and other construction professionals.

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Photo credits: Map via Wikipedia/Creative Commons License; Plan sketch via Frank Cecala & Andre Malok/The Star Ledger.