Infrasense Scans 15 Bridge Decks in Minnesota with Ground Penetrating Radar
Posted: 2013-2-5
Source:
PR Web
Infrasense, Inc., a national leader in infrastructure nondestructive evaluations, is
carrying out subsurface investigations for 15 bridge decks throughout
Minnesota's Metro region. The completion of this project will bring the total
bridge decks evaluated in Minnesota to 137 (over 2.5 million square feet) since
2009. Ground Penetrating Radar (GPR) tests were performed on each bridge
deck, accompanied by underside visual inspections. These tests provide a
condition assessment of the reinforced concrete bridge decks without requiring
any cores or exposed rebar, and with minimal disruption to traffic flow.
Ground penetrating radar (GPR) data is collected at highway speeds to estimate
rebar depth, corrosion conditions and deteriorated concrete. The GPR data is
collected in a series of lines spaced 3 feet transversely across the width of the
deck, with each line representing a cross sectional slice of the deck at a
particular offset. Decks in good condition consist of strong and uniform radar
reflections from the rebar. GPR data with weak and inconsistent reflections
indicate rebar-level deterioration in the bridge deck.
Recently a study evaluating the accuracy of Infrasense's results provided to the
Minnesota DOT was carried out by an independent consultant for MnDOT. The
study compared the predicted quantities for 12 decks surveyed by Infrasense
against subsequent construction repair quantities. The study found that, on
average, Infrasense’s predicted deterioration quantities were within 3.5 % of the
documented construction quantities.
Ground penetrating radar surveys provide transportation agencies with accurate
and comprehensive bridge deck condition information, enabling effective
preservation, rehabilitation, and replacement decisions. With large bridge deck
inventories, highway agencies have primarily relied on visual inspection at the
network level. Since the mechanisms of deterioration occur below the surface,
their manifestations are not readily seen in the visual inspections, often leading
to subsequent project-level focus.
Traditionally, highway agencies have employed sounding (chain or hammer) to
identify delaminated areas for project-level rehab. Although sounding has
proven reliable, the labor and closures required for a sounding survey makes it
prohibitive for obtaining data of a large number of decks. Also, sounding is not
effective when there is an asphalt overlay. In response to these limitations, a
number of highway agencies, including MnDOT, have utilized alternative
methods, particularly ground penetrating radar.
About Infrasense, Inc.
Since 1987, Infrasense, Inc. has applied the most current technologies to the
most difficult challenges in subsurface scanning. Infrasense’s engineers are able
to nondestructively extract critical information from a diverse range of
structures. The firm has conducted research to advance the field of subsurface
detection, while also providing valuable information to clients across the country.
To learn more about Infrasense and the services we provide, visit our website:
http://www.infrasense.com.
carrying out subsurface investigations for 15 bridge decks throughout
Minnesota's Metro region. The completion of this project will bring the total
bridge decks evaluated in Minnesota to 137 (over 2.5 million square feet) since
2009. Ground Penetrating Radar (GPR) tests were performed on each bridge
deck, accompanied by underside visual inspections. These tests provide a
condition assessment of the reinforced concrete bridge decks without requiring
any cores or exposed rebar, and with minimal disruption to traffic flow.
Ground penetrating radar (GPR) data is collected at highway speeds to estimate
rebar depth, corrosion conditions and deteriorated concrete. The GPR data is
collected in a series of lines spaced 3 feet transversely across the width of the
deck, with each line representing a cross sectional slice of the deck at a
particular offset. Decks in good condition consist of strong and uniform radar
reflections from the rebar. GPR data with weak and inconsistent reflections
indicate rebar-level deterioration in the bridge deck.
Recently a study evaluating the accuracy of Infrasense's results provided to the
Minnesota DOT was carried out by an independent consultant for MnDOT. The
study compared the predicted quantities for 12 decks surveyed by Infrasense
against subsequent construction repair quantities. The study found that, on
average, Infrasense’s predicted deterioration quantities were within 3.5 % of the
documented construction quantities.
Ground penetrating radar surveys provide transportation agencies with accurate
and comprehensive bridge deck condition information, enabling effective
preservation, rehabilitation, and replacement decisions. With large bridge deck
inventories, highway agencies have primarily relied on visual inspection at the
network level. Since the mechanisms of deterioration occur below the surface,
their manifestations are not readily seen in the visual inspections, often leading
to subsequent project-level focus.
Traditionally, highway agencies have employed sounding (chain or hammer) to
identify delaminated areas for project-level rehab. Although sounding has
proven reliable, the labor and closures required for a sounding survey makes it
prohibitive for obtaining data of a large number of decks. Also, sounding is not
effective when there is an asphalt overlay. In response to these limitations, a
number of highway agencies, including MnDOT, have utilized alternative
methods, particularly ground penetrating radar.
About Infrasense, Inc.
Since 1987, Infrasense, Inc. has applied the most current technologies to the
most difficult challenges in subsurface scanning. Infrasense’s engineers are able
to nondestructively extract critical information from a diverse range of
structures. The firm has conducted research to advance the field of subsurface
detection, while also providing valuable information to clients across the country.
To learn more about Infrasense and the services we provide, visit our website:
http://www.infrasense.com.
