News and Events - "Facilities"

Welcome to our newsroom! Here you will find the latest information about our company, projects and people. Browse articles published by our engineers and scientists in national publications and conference proceedings, view our press releases and read through news coverage of Terracon.

If you are a member of the media, you may contact our media relations representative at media@terracon.com.


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What’s Under the Hood (Concrete)?

Using ultrasonic echo tomography is a very useful structural diagnostic technique for diagnosing surface and internal concrete defects.

Ultra Sonic Echo Testing

Cracks, spalls, and surface defects such as voids, honeycombing, exposed rebar, etc., are typical symptoms of distress associated with reinforced concrete structures. These symptoms are typically identified as a precursor to a potentially larger issue hiding under the concrete surface. To an owner, this can mean unanticipated costs, potential impacts to building operations, and even safety concerns. The process of finding what has caused the defects will include an evaluation of distress symptoms such as cracks, voids, and surface defects. This effort requires a combination of visual assessment, and field and lab testing to develop a prognosis of the issue. One very useful and powerful tool used for assessment is ultrasonic echo tomography.

Defects in new or existing construction come from improper construction practices, improper design details, accidents, or sometimes natural disasters. These defects can impact the integrity of the structure and lead to sustainability and usability issues.

What is Ultrasonic Echo Tomography?

Ultrasonic echo tomography is a non-destructive test method used for evaluating the condition of hardened concrete by measuring the time of ultrasonic shear-wave transmitting in the hardened concrete. A shear-wave which is transmitted in an isotropic medium will be partly reflected when it reaches another medium with a different acoustic impedance. The amount of energy reflected depends on the significance of difference in the acoustic impedance of the two media. The effectiveness of ultrasonic echo testing in identifying defects inside concrete has been proven in many field applications.

3-D Ultra Sonic Testing

Diagnosis of A Reinforced Concrete Aeration Tank

This project involved a newly constructed cylindrical aeration tank that was designed to hold wastewater. The tank had an inner diameter of 63 feet, and a height of 18 feet. Our client observed concrete construction defects, including map pattern cracking, cold joints, and honeycombing on the exterior face of the reinforced 1-foot thick concrete wall of the tank after the forms were removed. These defects raised serious concerns related to the water-tightness of the concrete structure and its structural integrity.

Ultra Sonic Testing

To identify the probable causes of the observed defects, and determine if subsurface defects existed that were not visible on the surface, Terracon performed Ground Penetrating Radar (GPR) test and ultrasonic echo tomography test on the wall (on both interior and exterior faces) at several locations. The results of GPR test indicated inconsistent and less than specified concrete cover thickness near the exterior face of the wall which had contributed to the map pattern cracking mimicking the pattern of the reinforcing steel cage. Based on the 3-D models obtained from ultrasonic echo tomography test, the defects appeared to be limited to the vicinity of the exterior surface of wall, with no additional subsurface concrete flaws.  This was verified by through-wall coring performed on the concrete wall.

The findings allowed the client to determine that the new tank structure did not require demolition. They could be confident that the extent of observed surface defects were limited in nature. The structural engineer of record proposed a surface sealing repair coating to verify the water tightness of the structure. Significant demolition cost and schedule impacts were avoided.

Ultrasonic echo tomography is just one of the non-destructive techniques that can be utilized in evaluating concrete structures. With each unique project, a combination of a reasonable structural/materials evaluation and use of appropriate advanced non-destructive testing technology can help save time and money for all stakeholders.


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Air Barrier Testing Reveals Cost Reduction Solutions for School System

DSCN5239Ever notice a breeze in older buildings, even when it is not windy? Many buildings are leaking air, which means the owners are losing money. The Charlotte Mecklenburg School System (CMSS), one of the largest in the United States with a $1.3 billion operating budget, decided to take action to identify buildings in the school system that might be exhibiting air leakage. Full Story


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Just Testing or Real Teaming

The article discusses how advances in construction materials engineering testing and using advanced collaboration methods, can help achieve better results.


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Securing the Facility: Historic Data Center Roof Reconfiguration

Data Center Roof ReconfigurationWhen you’re responsible for housing the data center operations for the Southeast’s largest concentration of telecommunications companies, the words “leaky roof” are likely to cause you more than just a little anxiety. So when a renovation contractor requested that Terracon provide a roofing evaluation and specification to reroof the 10-story, 103-year-old 56 Marietta Street building in downtown Atlanta, it was clear that this project would require special attention. The historic brick hotel built in 1912 is now home to a 160,000-square-foot data center. The U-shaped building has four different levels of roofing which cover approximately 13,000 square feet. The third floor was Terracon’s particular focus and proved to be an unique opportunity for roof consultation.

EVALUATION

The project’s challenges began to mount early in the discovery phase. Terracon began by conducting destructive testing which identified that the building actually had two roofing systems – one of which was coal-tar pitch that dated back to the original construction. Coring roof samples then revealed that water had been running under the most recent roof system – a 15-year-old modified bitumen system. A subsequent moisture scan showed the third floor roof to be 100 percent wet. Full Story.


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ASHRAE Level 1 Energy Audit: A Tool for Success

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Handling Hazards: Environmental hazards like asbestos, PCBs and lead can change the complexion of a seemingly routine job.

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Building Envelope Strategy For a One-of-a-Kind Building Design

Scoobe-constructionWith a unique new design that includes an observatory dome 40 feet above the ground, half of its planetarium dome outside of the building, and multiple exterior cladding systems; some say the building looks like a spaceship.

The original San Antonio College Planetarium opened as part of the Alamo College System in 1961 and has entertained and educated more than 2 million people. The facility was rededicated in 1994 as the Scobee Planetarium to honor NASA astronaut and former San Antonio College student, Francis R. Scobee, who served as commander of the Space Shuttle Challenger’s tragic final flight in 1986. Complete story found here.


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Are you concerned about 1/8 of an inch?

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Full of Hot Air: How the IRC Fails to Address Effective Attic Ventilation

www.rci-online.org


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Retro Commissioning: the Direction

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