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Case Studies

Some cemeteries are hundreds of years old; unmarked graves can be common. Sandberg can undertake Ground Penetrating Radar (GPR) surveys for the detection of graves and cemetery surveys. Due to the sensitivity of these areas, a non-intrusive survey method such as GPR is ideal. A GPR survey team can cover a large area in a single day making it very cost effective survey technique.
Masonry (brick and concrete block) is commonly used for the construction of walls for buildings and retaining walls. Concrete blocks, especially those with hollow cores, offer various possibilities in masonry construction. Major performance and durability problems can arise if the reinforced cores are not fully filled with concrete, or if specified reinforcement is omitted. GPR can detect both missing reinforcement and voids.
The purpose of the survey was to establish any voids present within the stone wall construction of St Helen’s church, Broadgate London. The North wall and part of the East wall were nominated for survey. The wall construction comprised a stone inner and outer leaf, with a rubble fill in-between; the total wall construction is approximately 900mm to 1m thick.
The use of non-steel reinforcement is a relatively new innovation. One such product, Glass Fibre Reinforced Polymer (GFRP) bars comprise of polymer, glass, carbon or aramid fibres set in a resin to form a rebar rod. GFRP bars are not detectable by conventional cover-meters or the Hilti Ferroscan; they are detectable howeverby GPR.
Sandberg undertook a Ground Penetrating Radar (GPR) survey at Paddington Station. The purpose of the investigation was to identify areas of voiding, variations in construction detail, general features and anomalies.
The purpose of the investigation was to establish the location of voids and services. This would identify areas of potential weakness in the slab construction, prior to the proposed siting of heavy plant.
We are often requested to undertake surveys of floor slabs; warehouse floor slabs are particularly common. Typically we are required to determine the thickness of the slab, reinforcement distribution and the position of any ground beams and pile caps...
The properties and thickness of the ballast layer are critical for rail-track performance. Sandberg recently undertook a GPR survey on a length of railway track near Southampton to determine the thickness of railway ballast. Approximately 100 linear meters of track was investigated...
Sandberg used ground penetrating radar to investigate the construction detail and help identify weaknesses. Mr Ken Evans, the trust's building surveyor, said the ground penetrating radar study was one of several being carried out to "understand this unique and somewhat complex monument...