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Concrete and Structural Investigations. Issue No.19 – CSI:SUMO

Updated: Jan 31

Concrete and structural Investigations

It certainly no CSI:Miami, but CSI:SUMO (Concrete & Structural Investigations) gives you all the ‘concrete evidence’ you need!

Utilising the latest non-invasive survey techniques, SUMO’s engineering geophysics team have a solution to help you understand more about your concrete assets.

Ground Penetrating Radar (GPR), which is used predominantly in these investigations, can detect voids and delamination within the concrete, as well the thickness of the concrete slabs or walls themselves. Utilities within concrete can also be identified, along with steel elements such as beams, girders and metal plates. In addition, critical information which is required for structural assessments, such as post- tension cables and reinforced concrete bar (rebar) can also be easily mapped.

Condition of Concrete structures

SUMO can detect voids and delamination within the concrete. This allows for early detection of potential structural issues in a wide range of infrastructure.

The example below shows evidence of voids below the floor of a dry dock. The GPR survey detected a series of voids generally occurring at the interface between the granite setts forming the top layer of the dock floor and underlying mass concrete. The void anomalies correlated with the voids identified in a programme of coring that preceded the GPR survey.

GPR Radargram

Above : GPR Radargram showing voids beneath a dry dock floor at depths beween 0.75m and 1.5m

Concrete reinforcement (rebar)

GPR can locate and map the position and orientation of steel reinforcement and post tension cables within concrete. This information is critical during structural assessments, repairs, or modifications of existing concrete structures.

Rebar marked out on a concrete slab

Above : Rebar marked out on a concrete slab using a high frequency GPR.

Data is either recorded and/or interpreted on site, depending on your requirements, including budget and timescales, to produce 3 alternative survey outputs…

  1. Mark out survey only.

  2. Mark out survey with basic reporting.

  3. Post processed survey with full reporting.

Concrete Slabs

GPR can measure the thickness of concrete slabs or walls accurately. This is useful in determining the structural integrity of the concrete and identifying potential areas of weakness or failure.

In the example below the base of a concrete warehouse floor has been detected with GPR as a continuous, planar, horizontal high amplitude reflection. This occurred beneath the level of the rebar reflections in other scans. Post tension cables were identified in the data as discrete individual hyperbolic reflections of significantly wider diameter than rebar reflections, seen above the base of the floor. Further possible cables or structures were detected below the reflection from the base of the floor at 300mm depth.

GPR radargram

Above : GPR radargram showing the base of a concrete floor at 280mm depth, along with 3 post tension cables above the slab at 190mm depth and possible cables/structures below the slab at 300mm depth.

Buried Utilities

SUMO’s high frequency GPR is able to accurately locate and map underground utilities buried in concrete. This helps in avoiding accidental damage to these utilities during construction or excavation activities.

GPR data

Above : section view of GPR data showing a utility/service within the concrete below the rebar

Most sites take no more than a day to survey and immediate initial results may be presented on-site, with more detailed post-processed results, presented in AutoCAD, available shortly afterwards to suit your timescale.

Want to learn more?

Please pick up the phone and speak to Simon Haddrell or Richard Fleming on

01684 592266

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