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Updates from the field A brief look at a few of our recent projects Spring 2024

INFRASENSE INC is an engineering consulting firm that specializes in the non destructive evaluation NDE of bridge decks highway and airfield pavements tunnels parking structures and other transportation facilities The company was founded in December of 1987 with support from National Science Foundation NSF Small Business Innovative Research SBIR Grants Since then Infrasense has provided 36 years of NDE consulting and testing services using ground penetrating radar GPR infrared thermography IR seismic vibrations impact echo ultrasonic testing imaging and image processing projects 2023 Bridge Deck Scanning Concrete Structure Scanning Pavement Structure Evaluation Utility Locating Mapping Aerial Imaging Consulting Infrasense has completed projects for clients in all fifty US states Canada Europe Asia and the Middle East Our staff brings many years of experience and our methods are supported and continually improved through ongoing research and development efforts We provide our clients with highly accurate and actionable information enabling cost effective network level assessments and project specific maintenance and rehabilitation decisions Infrasense spent the past year performing fieldwork and data analysis across 26 different states and Canadian provinces while continuing to expand our Subsurface Utility Exploration SUE services and exploring exciting new capabilities of our proprietary software In 2023 our engineers evaluated over 1 000 bridges representing over 12 7 million square feet of deck area more than 4 300 miles of pavement and a range of other structures such as tunnels support columns and parking garages

Condition Evaluation of Bridge Decks Using GPR and IR Baltimore Maryland Bridge Decks 11 Deck Area 800 000 sq ft Technologies 3DGPR groundcoupled IR HRV Infrasense provided the Maryland Transportation Authority MDTA with comprehensive bridge deck condition evaluations for 11 decks in Baltimore Maryland that had a total combined area of more than 800 000 sq ft This work was performed on a team with KCI Technologies and Innovative Subsurface Evaluation Engineering iSee Direction of Traffic Both high resolution video HRV and infrared imagery IR were collected by Infrasense at highway speeds with no lane closures or disruption to traffic flow The data was then analyzed to map and quantify regions of patching spalling scaling and subsurface delaminations 3DGPR data was collected by iSee The data was then analyzed by Infrasense to determine the concrete cover over rebar and to map and quantify subsurface regions with concrete deterioration Infrasense combined all of the analysis results from HRV IR and 3DGPR into plan view condition maps for each of the 11 decks which were accompanied by comprehensive written reports to summarize the findings of the condition evaluations www infrasense com Direction of Traffic Comprehensive deck evaluations were carried out with 3DGPR infrared and video scanning The results will aid MDTA in programming and planning preservation maintenance and rehabilitation efforts

Network Level Bridge Deck Evaluations Using Vehicle Based and Aerial NDE Systems Wisconsin Bridges 463 Square Footage 3 332 612 Level 2 Technologies Aerial HRV sample Aerial IR sample The Wisconsin DOT s deck scanning policy which includes IR GPR and Impact Echo is necessary to determine accurate scope of deliverable projects certify structure work concepts for various funding programs and refine deterioration models used in the Wisconsin Structures Asset Management System WiSAMS GPR IR RAS Over the past 16 years Infrasense has performed Level 0 1 2 or 3 condition surveys on over 4 000 Wisconsin bridge decks representing approximately 39 million square feet These surveys were performed using some combination of vehicle based infrared thermography IR ground penetrating radar GPR and aerial IR In 2023 Infrasense evaluated a total of 463 bridge decks 283 decks using aerial IR testing 34 decks using vehicle based IR and 119 decks using vehicle based GPR Additionally Infrasense partnered with Advanced Bridge Inspections LLC which performed vehicle based rapid automated sounding RAS on 27 bridge decks In recognizing the value in this highly economical network level information Wisconsin DOT has recently implemented a policy to scan all bridge decks greater than 15 years old on a 5 year cycle The different levels of condition survey provide different levels of detail and efficiency Level 0 aerial IR surveys provide delamination quantity estimates and supporting imagery at the network level whereas Level 3 surveys combine high resolution vehicle based data with underside inspections to create a comprehensive plan view map of bridge deck conditions and calculated deck preparation quantities based on Type 1 Type 2 and Full Depth Repair classifications Aerial IR sample mapped www infrasense com

Evaluation of Pavement Structure for Interstate Highway Section Using FWD GPR and Core Data New Hampshire Land miles surveyed 19 2 FWD data 10 tests per mile GPR datapoints Continuous Cores 22 Infrasense working as a subconsultant to GreenmanPedersen Inc GPI carried out FWD and GPR testing to evaluate a 4 8 mile section of asphalt pavement along an interstate highway in northern NH The New Hampshire Department of Transportation NHDOT was seeking a detailed structural analysis in order to select the most appropriate treatment for this section of highway which was slated for major rehabilitation Cores and borings obtained by NHDOT were also made available to the project The project section is comprised of two lanes of traffic in each direction of travel as well as eight interchange ramps FWD data were combined with continuous pavement layer thicknesses generated from GPR data to determine pavement moduli structural number remaining service life and required overlay thickness The results showed that the existing pavement does not have enough structural capacity to provide a 20 year design The results also showed a notable difference between the structural capacity in the two directions of travel with one direction requiring more than double the overlay thickness on average Using this information the NHDOT selected full depth reclamation FDR of the existing pavement to improve the underlying base courses and repaving with 6 5 inches of new pavement The project is being designed by GPI and will also include replacing drainage and guardrail with construction expected to start in the Spring of 2026 www infrasense com Infrasense completed Ground Penetrating Radar GPR and Falling Weight Deflectometer FWD testing for 4 8mile section of interstate highway pavement in northern New Hampshire The data were analyzed to determine the structural capacity of the pavement structure

GPR data is an integral part of pavement evaluation summary PES reports which are a Georgia DOT prerequisite for any pavement rehabilitation plan of state roadways GPR Thickness Surveys of Various Pavements Georgia Lane miles surveyed 470 Total projects 12 Total ground truth cores 396 Average error of GPR thicknesses vs cores 9 1 In 2023 Infrasense Engineers conducted a series of pavement studies in Georgia focusing on over 470 lanemiles of Interstate highways to comprehensively characterize pavement structures The projects spanned various key highways each featuring 3 to 7 lanes in both directions numerous exit and entrance ramps and bridge decks approach slabs within the surveyed section of pavement For most of these projects data is collected using a dedicated survey vehicle equipped with vehicle mounted ground penetrating radar GPR operated at normal driving speeds with no lane closures or traffic disruptions GPR data is synchronized with GPS for high resolution geospatial information Potential voids or moisture in base and subgrade layers are identified in the GPR data and along with pavement layer thicknesses are provided in tabular and GIS formats Some projects require additional nondestructive evaluation methods including 3D GPR Array scanning for detailed evaluations of the rebar in continuously reinforced concrete pavements CRCP and stripping in asphalt pavements as well as traffic speed deflectometer TSD surveys to calculate layer moduli effective Structural Number required overlay thickness and even load transfer efficiency at concrete joints The results generated from GPR and other methods are utilized in Pavement Evaluation Summary PES reports which serve as prerequisites for rehabilitation planning and contribute significantly to ongoing efforts to enhance Georgia s roadway infrastructure www infrasense com

Traffic Speed Deflectometer TSD Data Saves Millions for Mississippi DOT on a State Highway Rehab Project Mississippi Miles Evaluated 12 7 TSD Measurements 12 700 GPR Scans 8 500 000 Cores 23 As part of a larger scale TSD 3DGPR data collection effort MSDOT identified a handful of project sections for more detailed investigation and rehab design recommendations In the summer of 2023 Infrasense and Nichols Consulting Engineers NCE completed the first project level analysis of a 12 7 mile section of a state highway constructed of asphalt pavement An initial review of the TSD and surface distress data showed the asphalt to be degraded This was further supported by core samples extracted by the DOT a number of which showed evidence of stripping within the asphalt As a result the objective of the TSD and GPR analysis was to identify the extent of the stripping and with this information provide rehabilitation recommendations The GPR data was analyzed to identify the thickness of the asphalt pavement and underlying base layers as well as detect areas with high reflection activity within the asphalt material The TSD data analyses leveraged the results of the GPR analysis to calculate SCI12 asphalt modulus subgrade modulus effective structural number and required overlay thickness The rehab recommendations generated from this effort and will ultimately save Mississippi DOT approximately 15 million dollars in construction costs compared to what was originally planned Infrasense worked alongside Nichols Consulting Engineers NCE to analyze traffic speed deflectometer TSD and ground penetrating radar GPR data provided by ARRB Systems to detect stripping within the asphalt pavement Calculated Outputs Corresponding with Stripping Signal reflection activity from GPR analysis SCI12 from TSD data Effective Structural Number from TSD analysis www infrasense com

A suite of nondestructive methods were used to map underlying defects in the piers and abutments Bridge Deck and Substructure Condition Evaluations Berkshires Massachusetts Elements Tested Deck 8 Pier caps 48 columns NDE Testing Methods GPR HRV Impact Echo Rebound Hammer This past summer Infrasense performed a comprehensive condition evaluation of the bridge deck and substructure elements for a bridge carrying a state highway in the Berkshires in western Massachusetts The condition evaluation included the use of GPR high resolution video HRV infrared thermography IR impact echo IE and rebound hammer RH testing The evaluation included the 865 foot long top deck end limit abutment walls 8 pier cap structures and the 48 total supporting columns to identify and map quantities of concrete deterioration The top deck survey including the HRV IR and GPR testing was collected by Infrasense at normal traffic speed with no lane closures or disruptions to traffic flow The underside data collection was completed using the GPR IE and RH tools with total access requirements ranging from 8 feet to a maximum of approximately 25 foot heights The field crew was able to access all the elements on foot using ladders and by way of a large mobile scissor lift The combined datasets were analyzed in parallel to map and quantify regions of concrete deterioration rebar spacing and cover subsurface delaminations spalling and patching on each of the bridges structural elements The final results were derived from the combined NDT findings and displayed with the final report and statistical analysis as plan and profile view maps www infrasense com

Subsurface Utility Engineering Survey in Historic Harvard Square Cambridge Massachusetts Test methods Ground Penetrating Radar GPR Electromagnetic Induction EMI Total surveyed area 152 000 sq ft SUE Quality Level B In August of 2023 Infrasense pahked the GP ah in Harvahd Yahd to perform a SUE Quality Level QL B survey The objectives of this survey were to map the location of underground utilities and buried trolley tracks determine the asphalt thickness and identify the limits and depth to the top of the Red Line subway tunnel along Massachusetts Avenue in Cambridge Massachusetts Level B surveys involve the use of geophysical testing methods to determine the existence and horizontal location of subsurface utilities The Harvard Square survey included the use of GPR and EMI tools as the primary detection instruments and GPS for positional accuracy The infield located utilities combined with those identified using GPR data collection were reviewed against as built drawings and test pit results provided by the client Kleinfelder The field work included multiple nights on site and two different GPR setups using different antenna frequencies and deployments A pushcart system with a 400 MHz antenna capable of penetrating 10 12 feet below the surface was used to detect underground utilities and subway tunnels A vehicle based horn antenna was used for the pavement thickness testing The results of this multi phase survey were provided as a utility map showing the locations and depths of EMI and GPR identified utilities tabular and graphical pavement thickness profiles and a plan view contour map of the tunnel limits and depths www infrasense com As a prequalified Subsurface Utility Engineering SUE firm in Massachusetts Infrasense is ready to provide assistance in meeting new SUE Level B requirements set forth by a Massachusetts Department of Transportation MassDOT engineering directive

Urban Network Level Pavement Structure Evaluation Toronto Ontario Canada Project lane kilometers 2671 5 Project road segments 10 096 Days of Data Collection 17 Infrasense engineers got reacquainted with the metric system this summer while collecting and analyzing over 2600 kilometers 1669 miles of pavement data in Toronto Canada Working for the Prime Contractor International Cybernetics ICC Infrasense is providing the ground penetrating radar GPR pavement thickness data for this multiyear project that will provide the city of Toronto with an up to date pavement management system PMS Pavement segments ranged from quiet tree lined residential streets to busy downtown city blocks to the Gardiner Expressway Data was collected using a single air launched GPR antenna mounted to a survey vehicle and equipped with a high resolution GPS and a distance measuring instrument DMI that collect geospatial and distance data synchronously with the GPR data Despite the complex network of roads to scan Infrasense field engineers managed to collect the data in just 17 days The pavement structure data are an invaluable component of Toronto s Pavement Management System The pavement layer thicknesses are used in planning preservation treatments and rehabilitation efforts Network level pavement evaluations for metropolitan areas such as Toronto present unique challenges Infrasense was able to add new features into our proprietary software in order to solve project specific problems such as GPS interference in downtown areas and daily coverage QA during data collection Infrasense worked closely with ICC to provide the GPR thickness results reported at 1 meter intervals in both tabular and geospatial formats that can be efficiently integrated into ICC s own project deliverables

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