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Updates from the field A brief look at a few of our recent projects Spring 2023

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 35 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 2022 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 24 different states and Canadian provinces while expanding our services to include Falling Weight Deflectometer FWD testing and increasing our Subsurface Utility Exploration SUE capabilities Our engineers evaluated nearly 1 000 bridges representing over 12 million square feet of deck area more than 3 300 miles of pavement and a range of other structures such as parking garage decks and floor slabs Last year Infrasense expanded its knowledge and capabilities by welcoming several new team members who bring a combined 40 years of experience with a variety of NDE techniques The following pages showcase a few of our most notable projects from 2022

Infrasense Looks FWD to More Falling Weight Deflectometer Projects in the Northeast New Jersey Lane miles surveyed 162 Pavement sections 14 FWD test locations 1 412 Calculated Outputs Asphalt Modulus at 68oF Concrete Modulus Subgrade Modulus Modulus of Subgrade Reaction Effective Structural Number Load Transfer Efficiency In the fall of 2022 Infrasense hitched up our new falling weight deflectometer FWD trailer and headed south to New Jersey to conduct pavement structure evaluations of 14 state highways Sections included full depth asphalt as well as asphalt over concrete composite pavements FWD testing was performed at over 1 400 locations along the project sections using a Dynatest Model 8200 trailermounted system Deflections were measured utilizing seven calibrated sensors spaced at specified offsets from the load cell Testing was performed in accordance with ASTM D4694 09 2020 and ASTM D4695 03 2020 and all test locations were documented in terms of linear distance using a DMI and with GPS coordinates The FWD deflection data was used to calculate the pavement layer moduli and subgrade modulus as well as the load transfer efficiency LTE of the concrete slabs under the AC surface layer Supplementary to the FWD testing a vehicle based ground penetrating radar GPR survey of 150 lane miles yielded continuous pavement layer thickness data along prescribed offsets within the project sections Over 200 cores were also available which aided the GPR analysis by confirming layer classifications and depth calculations The finalized layer thickness results were combined with the FWD results described above to calculate effective Structural Number SNeff The FWD and GPR results provided the client with valuable insights on the pavement condition and structural capacity and were utilized to come up with effective preservation and rehabilitation designs www infrasense com In 2022 Infrasense acquired a powerful piece of nondestructive testing equipment a falling weight deflectometer FWD After receiving training and calibrating the unit Infrasense began collecting FWD data including over 1 400 test locations on pavement throughout New Jersey

Following the completion of the analysis the state DOT provided chain drag inspection results for a small group of bridges On average the aerial IR survey results correlated well with the chain drag inspections providing delamination quantities within 4 of the delamination quantities obtained by traditional sounding Aerial Infrared Deck Evaluations Help DOT Budget Go Far in Fargo ND North Dakota Bridges 85 Square Footage 1 008 245 visual map Days of Data Collection 1 Decks with chain drag comparison 14 IR raw data map IR data with chain drag based areas R data with IR based areas Infrasense provided aerial infrared thermography Aerial IR bridge deck evaluations in 3 new states including North Dakota where IR data was collected on 85 bridge decks in a single day from a fixed wing aircraft These bridges were located along Interstates 29 and 94 and accounted for over 1 million square feet of roadway deck area Deck condition results were provided to the North Dakota Department of Transportation NDDOT as plan view maps of deck delamination patching and spalling Following the completion of the Aerial IR analysis NDDOT provided chain drag survey results for 14 bridges included in the Aerial IR project in order to compare the results of the two deck evaluation methods Overall the two methods compared favorably particularly for decks with greater quantities of delamination The comparison showed an average difference of 4 between the chain drag and Aerial IR delamination results Over the past few years Infrasense has been the industry leader in developing a methodology for network level aerial infrared scanning of bridge decks which offers a variety of advantages over traditional bridge deck inspection methods such as sounding and coring Condition data for hundreds of bridge decks can be collected in a single day without lane closures traffic disruptions or crews on the deck The adaptation of infrared to a highly efficient fixed wing aerial based survey has opened the door to low cost network level delamination surveys www infrasense com

Infrasense Provides Deck Condition Evaluations in Wisconsin for Tenth Straight Year Wisconsin Bridges 593 Square footage 6 758 223 Level 0 decks 255 Level 1 decks 101 Level 2 decks 18 Over the past 15 years Infrasense has performed Level 0 1 2 or 3 condition surveys on over 3 600 Wisconsin bridge decks representing approximately 36 million square feet These surveys were performed using some combination of vehicle based infrared thermography IR ground penetrating radar GPR and aerial IR In 2022 Infrasense evaluated 255 decks using aerial IR scanning 115 decks using a combination of vehicle based GPR and IR and an additional 223 decks were re analyzed using data from previous projects in order to provide additional condition information In recognizing the value in this highly economical networklevel 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 offers a variety of advantages over traditional bridge deck inspection methods such as sounding and coring Condition data for hundreds of bridge decks can be collected in a single day without lane closures traffic disruptions or crews on the deck The efficient data collection can be scheduled for the most optimal weather conditions ensuring high quality data adequate for delamination detection www infrasense com The Wisconsin DOT s deck scanning policy which includes IR GPR and IE 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

As a prequalified Subsurface Utility Engineering SUE firm in Massachusetts Infrasense is ready to provide assistance in meeting new SUE Quality Level B requirements set forth by a Massachusetts Department of Transportation MassDOT engineering directive Infrasense Utilizes NDE Tools for Local Subsurface Utility Engineering Project Massachusetts Test Methods Ground Penetrating Radar GPR Electromagnetic Induction EMI High Resolution Video HRV Approximate Survey Area 1 million sq ft Quality Level B Deliverable Format CADD Compatible Service Lines Located Gas Water Drainage Communications In June of 2022 Infrasense performed a SUE Quality Level QL B survey to map the location of underground utilities of known and unknown origin along 2 miles of a state highway in southeastern Massachusetts Level B surveys involve the use of geophysical testing methods to determine the existence and horizontal location of subsurface utilities The work is part of a new engineering directive issued by MassDOT and will result in safer job sites with fewer unexpected problems associated with subsurface utilities The 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 provided by the service providers and those consolidated by a local engineering design firm The field work included multiple days on site running multiple systems simultaneously EMI tracing was performed on all local service lines and service access points along the 2 mile project limits The locations and depths of new utilities were overlaid onto the client s CAD basemap The SUE survey confirmed the presence and refined the positions of gas water drainage and communications lines and identified an unknown service line along a majority of the project section that was not shown in the as built drawings www infrasense com

Detailed view of SUE QL B CAD Results provided by Infrasense

Infrasense Leads The Team for Bridge Deck Condition Evaluations Montana Bridge Decks 44 Square Footage 466 000 Technologies Ground Penetrating Radar GPR Infrared Thermography IR High Resolution Video HRV Rapid Automated Sounding RAS Chloride Ion Concentration Testing Infrasense led the way as the prime contractor for bridge deck condition evaluations in the Big Sky state Working on a team with ALLWEST Testing and Engineering of Missoula Montana and Advanced Bridge Inspections ABI of American Fork Utah Infrasense provided the Montana Department of Transportation MDT with comprehensive bridge deck condition reports on 44 decks across the state An array of data was collected on each bridge deck depending on the evaluation level prescribed by MDT High speed GPR IR and HRV data was collected by Infrasense with no lane closures or disruption to normal traffic flow This data was used primarily to evaluate the conditions of the bridge deck surface and to determine the concrete cover over rebar ABI provided data collection and analysis of rapid automated sounding RAS to detect rebar level delamination This data was collected using rolling closures to minimize the disruption to normal traffic flow ALLWEST provided chloride concentration ion testing for samples they obtained from prescribed decks using temporary lane closures Chloride ion data is valuable for measuring the concentration of chlorides that have seeped into the deck and will eventually cause rebar level corrosion The results of all testing methods were combined into a single plan view condition map for each deck and accompanied by a comprehensive written report to summarize the findings of the condition evaluation www infrasense com Last year Infrasense led a team to evaluate the condition of 44 bridge decks throughout Montana with more deck testing planned for 2023

GPR Thickness Surveys of Various Georgia Pavements Georgia 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 Lane miles surveyed 167 Total projects 3 Total ground truth cores 163 Average error of GPR thicknesses vs cores 7 5 Infrasense engineers traveled south to Georgia several times in 2022 for various pavement studies across the state These pavement surveys were performed on over 167 lane miles of Interstate highways in order to characterize the pavement structure and to identify and map potential areas of voids or moisture in the base and subgrade layers Pavement thickness and condition results were provided in tabular and GIS formats For each project data was collected using a dedicated survey vehicle stationed in the Southeast U S equipped with vehicle mounted ground penetrating radar GPR operated at normal driving speeds with no lane closures GPR data was collected synchronously with GPS data to present pavement structure results with high resolution geospatial information The GPR data and results are used in pavement evaluation summary PES reports for the Georgia Department of Transportation GDOT A PES is a prerequisite requirement for any pavement rehabilitation plan of a state roadway and GPR data is an integral part of these reports GPR pavement data is relied upon to provide engineers with a detailed picture of a roadway s subsurface condition and makeup GPR has been used to accurately delineate blacktopped Portland concrete pavements from full depth asphaltic concrete pavements where surface observations and historical project searches provided limited help Knowing this the engineer is able to provide better recommendations for rehabilitation www infrasense com

LAYER MODULI EFFECTIVE SN Evaluation of Pavement Structure for Highway Section Using FWD TSD and GPR New Hampshire 11 6 FWD Locations 10 per mile TSD Locations Continuous Infrasense field engineers took a short trip north to New Hampshire to put our new FWD system to work along with our driving speed GPR system to evaluate a 5 8 mile section of asphalt pavement 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 experiencing full depth cracking TSD data collected by ARRB in 2020 using their iPAVe system was made available to the project for a more robust analysis of the pavement condition Though not an objective of the project the availability of FWD and TSD data along the same section of roadway provided a unique opportunity for comparison which showed a strong correlation between the two datasets The FWD and TSD 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 is not structurally adequate to carry the traffic loads and a major rehabilitation would need to be performed As a result the NHDOT has chosen to remove the failed pavement and replace it with a thicker section to restore this section of roadway to new condition and allow more cost effective pavement preservation techniques to be utilized in the future www infrasense com REQUIRED OVERLAY Infrasense worked alongside ARRB Systems and Nichols Consulting Engineers NCE to collect and analyze Ground Penetrating Radar GPR Falling Weight FWD and Traffic Speed Deflectometer TSD data for a 5 8 mile section of New Hampshire highway pavement SNeff Lane miles surveyed REMAINING LIFE

Parking decks are just one of the types of concrete structures that Infrasense can evaluate using nondestructive testing methods Like bridge decks parking decks can be exposed to moisture and corrosive road salts causing concrete deterioration and necessitating inspections and repairs A Walk in the Park ing Garage Condition Evaluation of Target Areas of a Parking Deck New Jersey Test Results Concrete Deterioration Mid slab Rebar Cover Rebar Layout Surveyed Sections 8 Total Surveyed area 8000 s f In November of 2022 Infrasense carried out a ground penetrating radar GPR survey on 4 levels of a parking garage in New Jersey to map the concrete subsurface conditions within eight specified areas A 1500 MHz groupcoupled antenna system was deployed using a survey cart Testing was performed in a single day with minimal disruption to normal parking operations The eight test locations were selected based on visual inspection information such as spalling and evidence of corrosion The GPR survey covered specific elements of the garage including ramps transition slabs and parking space slabs In addition to the condition analysis the GPR data were collected using a high scan rate to map the individual steel bar spacing and cover The survey results were provided to the client in planview and statistical formats indicating the location of deterioration as well as the shape and area The reinforcement mapping results revealed the placement of the bars to be inconsistent with spacing varying between 2 and 12 inches and no regular pattern The final deterioration and reinforcing steel maps were overlaid on the site basemap and will be used by the client for rehabilitation planning www infrasense com

In 2022 Infrasense welcomed some new key contributors to our team including Ralf Birken David Vines and Parker Aubin They bring a combined 40 years of experience with nondestructive evaluation NDE including hardware and software development data collection analysis and reporting Ralf Birken Ph D Ralf joined Infrasense as Principle Engineer with over 20 years of research and engineering experience in industry and academia focusing on Subsurface Utility Engineering SUE pavement and bridge deck inspection and NDE He has a Ph D in Geophysical and Geological Engineering from The University of Arizona He is an inventor listed on 7 patents the author of 4 book chapters 15 journal publications 70 conference proceedings and 30 other miscellaneous publications posters or major technical reports In his spare time Ralf is a passionate basketball player coach and Celtics fan David Vines Ph D David has a Ph D in Civil Engineering from Northeastern University His academic and career focus has been on sensor systems data processing algorithms and software in the areas of pavement inspection and NDE He has over 10 years of experience at researching designing testing and deploying these technologies for customers as well as technical writing and presentations In his spare time if not with his daughter Olivia David can be found photographing wildlife or going for a run Parker Aubin Parker holds a B S in Mathematics from Boston College undergraduate research in geophysics and a M S in Civil Engineering from Tufts University Geosystems concentration Before joining Infrasense Parker worked for over 4 years in the field of Geotechnical Engineering He brings his wide experience from the civil engineering profession and his passion for geophysics and NDE In his free time Parker is driving or camping in one of his old VWs or tinkering with them to keep them going

21 G Olympia Avenue Suite 45 Woburn Massachusetts 01801