Articles

Infrastruct Welcomes New Engineering Staff to the Company

In August, Ethan Mannion and Dr Shahnur Alam Sourav joined Infrastruct to work on structural testing and investigation projects in Ireland and the UK.

Ethan is a Mechanical Engineer with experience in both the manufacturing and construction industries.

Infrastruct Welcomes New Engineering Staff to the Company
Shahnur recently completed his PhD in UCD and joins Infrastruct to further enhance our testing and investigation services.

Infrastruct Welcomes New Engineering Staff to the Company
Since joining Infrastruct, Ethan and Shahnur have been involved in structural investigations in multi-storey buildings, moisture monitoring in both new and existing buildings, non-destructive testing to determine floor slab depth and integrity in open tanks and a Special Inspection of a 72 year old concrete bridge.

These projects involved many types of tests including:

  1. Covermeter and GPR scanning of different types of structural elements
  2. Half-Cell Potential and Resistivity mapping on structural elements
  3. Relative humidity mapping in floor slabs
  4. Pulse Echo mapping of a bridge deck to determine the in-situ depth of the deck
  5. Ultrasonic Pulse Velocity (UPV) testing on structural elements (SonReb Analysis)
  6. Rebound Hammer testing on structural elements
  7. Sampling and testing for carbonation depth and chloride ion concentration of concrete
  8. BRE Screed testing on repairs floors
  9. Anchor testing
  10. Defects mapping

Infrastruct Welcomes New Engineering Staff to the Company
All testing and investigation works completed by Infrastruct is supervised by a Chartered Engineer and we prepare a detailed interpretative report with AutoCAD drawings (as required) for our Clients.

Articles

Impact Echo Testing on Existing Concrete Floors

Impact Echo is a non-destructive test system for examining and assessing concrete elements in structures. Impact Echo is used for:

  1. Location voids and honeycombing in concrete structures (depth of defects in elements)
  2. Locating delamination (at reinforcement) in concrete structures
  3. Determining voids in post-tensioning ducts
  4. Structural thickness of elements.

Infrastruct uses the Germann Instruments DOCter Impact Echo system.

Impact Echo uses a sharp mechanical impact on the concrete surface to generate stress waves that penetrates through the concrete. The stress waves travels into the concrete and are reflected from the back wall of the element or from an anomaly within the element, for example a void.  The reflected stress wavesare picked up using a sensitive displacement transducer placed about 50mm from the impact point.

Impact echo is an expert system requiring a detailed knowledge of its use, the technique and knowledge of the concrete element under test.

Examples of Use:

  1. Locating Voids in Post-Tensioning Ducts

The team in Infrastruct were requested to non-destructively examine post-tensioned downstand concrete beams and determine the location and condition of the ducts.

We used high frequency GPR to locate the duct profile within each concrete beam and we used the DOCter Impact Echo system at small intervals to assess and record the void condition within the ducts. This was very successful at locating voids in post-tensioning ducts.

Selected duct and tendon exposures were made to confirm the findings of the DOCter Impact Echo system.

Figure 1 shows the DOCter Impact Echo system in use on the Bridge and Figure 2 shows a voided post-tensioning duct located using the DOCterImpact Echo system.

  1. Locating Piles under Existing Floor Slab

The team in Infrastruct were asked to determine, non-destructively, the depth of a concrete slab and to locate buried piles under the concrete slab.

We used a combination of test systemsincluding the impact echo which was particularly useful in areas of congested reinforcement. The piles were located and marked up on the concrete surface and a detailed report prepared for the Client.

Figure 3 shows the DOCter Impact Echo system in use on the floor slab to locate changes in the thickness of the floor.

Articles

Moisture Testing in Concrete Floor Slabs

Concrete floors and screeds should be dry enough to allow resilient floor coverings to be installed without follow-on moisture-related damage.

If moisture is present in a concrete floor slab or screed it can:

  1. Cause damage to the floor covering material
  2. Affect certain flooring adhesives
  3. Cause bubbling, blistering or delamination of the floor coverings
  4. Affect certain types of levelling compounds or underlay materials
  5. Damage certain screed materials
  6. Affect or damage wall or skirting materials or finishes.

The drying out of a concrete floor slab (moisture leaving the slab over time) is typically a slow process and a common method for assessing the floor condition is using in-situ relative humidity probes.

Infrastruct use the Tramexhygro-i2probes for in-situ relative humidity monitoring of concrete floor slabs and screeds.

ASTM Standard F2170-19a ‘Standard Test Method for Determining the Relative Humidity in Concrete Floor Slabs Using in-situ Probes’ describes the quantitative determination of the percent relative humidity in concrete slabs.

A summary of the procedure to measure relative humidity in concrete floor slabs is as follows:

  1. In hardened concrete floors or screeds, drill a hole with a specific diameter in the floor to a predetermined depth and clean out using a hole brush and vacuum system. Avoid embedded reinforcement, if present, in the slab. See Figure 1 showing rotary drilling in a concrete slab with a dust removal system prior to inserting the plastic sleeve.
  2. Push a plastic sleeve, of suitable length, into the drilled hole and cap off and seal. The plastic sleeve allows measurement of the relative humidity of the concrete at a specific depth.
  3. Install the relative humidity probe into the hole and recap as shown in Figure 2.
  4. The Standard F2170-19a recommends a defined number of RH% probes per square meter in the floor slab and requires certain test locations to gather as much information on the moisture distribution in the floor.
  5. Allow at least 24 hours for the RH% probes to achieve moisture equilibrium within the sleeve before making the relative humidity measurement. We measure relative humidity in concrete and screeds using the Tramex CMExpertII system as shown in Figure 3.
  6. Record the result carefully ensuring the reading does not drift by >1% and the probe is in temperature equilibrium with the floor.

Non-Destructive Moisture Measurement

To scan concrete floors for changes in the moisture content, the Infrastruct Team also uses the Tramex CMExpertIIdigital meter (Impedance Mode). In this mode, the meter measures the surface moisture using the electrical impedance principle.

Measurements are non-destructive and large areas can be scanned quickly. See Figure 4 showing the Tramex CMExpertIIdigital meter in operation on a floor slab.

Articles

Permeability Testing On Underground Concrete Tanks

In early 2020, Infrastruct was requested to carry out in-situ permeability testing on underground reinforced concrete tanks for a large and well-known Irish manufacturing Company. The testing on the concrete tanks was required to assess, non-destructively, the in-situ quality of the concrete and its resistance to water penetration prior to entering service for the Company.

The permeability of concrete to liquids has major implications for the durability of the concrete during its service life and on its ability to retain the liquid within the tank structure. While there is no one standard test method recommended, Infrastruct uses the Germann Instruments GWT test system for the on-site assessment of water permeability.

The GWT system can be used for:

1. Evaluation of the water permeation of the skin-concrete in finished concrete structures.
2. Testing the water tightness of construction joints and sealed control joints.
3. Testing the concrete surface before and after the application of a protective water-proof coating to assess the effectiveness of the coating and its application.
4. Evaluation of the water permeation properties of masonry structures.

Photographs 1 and 2 below show the GWT test system on the reinforced concrete walls of the underground reinforced concrete tank. Note the marked-up location of the embedded reinforcement within the walls, it is recommended to avoid testing over the reinforcement.

The results of the GWT testing was recorded on-site by our Engineers and a comprehensive report, with interpretation, was prepared for our Client.

For more information on GWT testing or any structural testing and investigations, please contact Dr Thomas Callanan in Infrastruct Asset Management Services Limited.

Articles

BRE Screed Testing On Floors

Infrastruct was requested by a materials manufacturer in January 2020 to carry out in-situ testing on a floating screed floor.

The methodology to assess the In-situ Crushing Resistance (ISCR) of bonded, unbonded and floating screeds is provided in BS 8204-1:2003 ‘Screeds, Bases and In Situ Floorings – Part 1: Concrete Bases and Cementitious Levelling Screeds to receive Floorings’.

Infrastruct used the BRE Screed Tester for the in-situ testing on this screed. The equipment used a 2kg weight (floating screed, Category C only) dropped 1m down a vertical rod onto a foot piece to impact the screed surface over a 500mm2 area. The surface indentation caused by the four consecutive blows onto the screed in the same area was measured and recorded using a simple portable dial gauge device.

This test is very useful for identifying zones of poor compaction beneath an apparently good surface.

Photographs 1 and 2 below show the BRE Screed Tester using the 2kg weight on the Category C floating screed and the portable dial gauge device, zeroed on the test area before the testing and replaced on the test area after the testing to measure the indentation depth.

The results of the testing was recorded on-site by our Engineer and a comprehensive report, with interpretation of the results, was prepared for our Client.

For more information on screed testing, please contact Dr Thomas Callanan in Infrastruct Asset Management Services Limited.

Articles

Non-Destructive Testing On Reinforced Concrete Tanks

Infrastruct was contacted by the Consulting Engineers on a project to carry out non-destructive testing on a new, above ground reinforced concrete tank. The tank was designed to retain sewage as part of the treatment process and the Engineers needed confirmation that there were no hidden defects or anomalies within the walls of the structure.

Random 1200x1200mm test areas were selected on the walls of the structure and the following testing was carried out:

1. GPR surveys on selected sections of the concrete walls to identify the location of embedded reinforcement and scan for evidence of hidden voids within the walls.
2. Check the in-situ concrete integrity using the MIRA pulse echo tomographer to generate cross section images of the concrete walls to examine the concrete for internal voids or other hidden defects within the concrete.
3. Water permeation testing (GWT) to assess the permeability of the finished concrete tank walls (permeation of water under an applied pressure of 100kPa).
4. Ultrasonic Pulse Velocity (UPV) measurements to evaluate the depth of selected cracks.
5. Crack width measurements using a microscope to check the width of selected cracks.

Photographs 1, 2 and 3 below show the test equipment in use on the walls of the tank.

The results of the testing was recorded on-site by our Engineers and a comprehensive report, with interpretation of all the results, was prepared for our Client.

For more information on non-destructive testing of concrete structures, please contact Dr Thomas Callanan in Infrastruct Asset Management Services Limited.

Articles

Reinforcement Scanning On Concrete Slats & Slabs

In late 2019, Infrastruct was instructed by the Contractor building a large Slatted Unit in the Midlands to carry out a covermeter survey to confirm the presence of embedded reinforcement in each concrete slat and slab forming the Slatted Unit.

Infrastruct used a combination of the following equipment to confirm the presence of reinforcement in each slat and slab in the Slatted Unit:

1. Proceq PM-650 Covermeter with the extension handle for line scanning on the concrete surface
2. Hilti PS-1000 X-Scan GPR system to locate reinforcement deep within certain slabs.

Photographs 1 and 2 below the Proceq PM650 and Hilti PS-1000 being used to scan the top surface of the concrete elements to locate and confirm the presence of embedded reinforcement.

The results of the testing was recorded on-site by our Engineer and a comprehensive report, with interpretation, was prepared for our Client.

For more information on testing concrete elements and structures for agricultural use, please contact Dr Thomas Callanan in Infrastruct Asset Management Services Limited.

Articles

Building Investigations

Late in 2019 Infrastruct was instructed by our Client to carry out testing and investigations on an old multi-storey building which was showing evidence of significant distress and deterioration. The goal of the structural testing and material investigation works was to conclusively determine the cause of the distress and deterioration.

The testing and investigation works included:

1. Reinforcement cover and layout surveys
2. Half-Cell Potential surveys
3. Carbonation depth measurements
4.Concrete dust sampling for chloride content analysis (laboratory testing)
5.Ultrasonic Pulse Velocity (UPV) testing on concrete beams and columns
6. Coring for:
a) Compressive strength and estimation of the characteristic compressive strength of the concrete
b) Petrographic examination of the concrete.

Photographs 1 and 2 below show the testing on the columns to determine the cover to the reinforcement and the UPV results for in-situ concrete quality assessment.

The results of the testing were recorded on-site by our staff and a comprehensive report, with interpretation, was prepared for our Client. The cause of the deterioration in the concrete was determined by the testing programme.

For more information on structural testing and investigations on buildings or other structures, please contact Dr Thomas Callanan in Infrastruct Asset Management Services Limited.

Articles

Non-Destructive Testing on Railway Track Slabs

Infrastruct was part of an engineering team that carried out a range of structural testing and investigations on reinforced concrete track slabs in a tunnel in Scotland.

Infrastruct used combination of non-destructive testing systems on this project to investigate the integrity of two separate sections of track slab.

The non-destructive testing systems used by Infrastruct to locate and target weaker areas or to locate areas with structural changes in the track slab were as follows:

  1. s’MASH Impulse Response to survey on the top surface of the concrete track slab. This testing was completed in a grid pattern on the top surface of the track slab to rapidly identify suspect areas for further investigations using other testing systems. In total, there were 328 s’MASH test points recorded and analysed.
  2. MIRA Pulse Echo Tomography on the top surface of the concrete track slab to graphically examine the concrete integrity in the suspect areas of the track slab.  Selected areas on the slab were scanned using the MIRA pulse echo system to determine if major voids or anomalies were present within or beneath the track slab.
  3. Impact Echo (Olsen CTG-2D) to survey the selected locations and map the changes in the slab thickness.
  4. Ground Penetrating Radar (GPR) to survey the slab using a 1GHz antenna on the top surface and locate embedded reinforcement and other services.

The combination of s’MASH Impulse Response, MIRA Pulse Echo Tomography, CTG-2D Impact Echo and GPR proved successful on this project in determining the defects under the track slab.

The results of the non-destructive testing were recorded on-site by our Engineers and a comprehensive report, with interpretation was prepared for our Client.

For more information on non-destructive testing on structures, please contact Dr Thomas Callanan in Infrastruct Asset Management Services Limited.

Articles

Post-Tensioning Special Inspection on 3 Span Bridge

Infrastruct AMS with a well-known civil engineering contractor recently completed a Phase 3 Post-Tensioned Special Inspection (PTSI) on a large three span bridge in the West of Ireland.

Combining the techniques of Ground Penetrating Radar (GPR), Impact Echo and Linear Polarisation Resistance (LPR) we were able to plot the post-tensioning duct profiles in each beam, non-destructively assess if voiding was present in the ducts and measure the rate of corrosion on the embedded reinforcing bars.

Duct and tendon exposures at selected locations confirmed the Impact Echo test results showing fully grouted sections as well as partially or fully voided sections in the ducts.

The pictures below show the marked-up duct profiles on the beams, the Impact Echo testing and a duct and tendon exposure in a fully voided section of post-tensioning duct.

For more information on any of the specialist testing described above or indeed any structural testing and investigations please contact Dr Thomas Callanan in Infrastruct Asset Management Services Limited.

Posts navigation