Assessments of Structural Form

Our aging, and in some instances ‘new’, buildings and structures commonly do not have any ‘as-built’ information, or if they do, it may not be correct. The maintenance, repair, refurbishment and strengthening of existing structures requires detailed and accurate ‘as-built’ information if projects are to progress as efficiently and safely as possible.  CRL Surveys can assist in the clarification of ‘as-built’ details, as follows:

At selected locations the form and type of construction, together with the relationships between adjacent, discrete, elements can variously be investigated using a combination of non-destructive direct / indirect measurement, the removal of internal, finishing-panels (with due regard and safety protocols for asbestos, lead-paint, historic plasters and other potentially hazardous materials and zoonoses), together with remote scanning using various covermeters and related scanners, ultrasonics and radar.

However, where necessary, increasingly damaging and intrusive techniques, including remote inspection using various borescopes /endoscopes and breaking-out will be employed.

NB:  Our intensions will be to maximise the information gathered, whilst minimising the extent of disruptive and damaging intrusion.

For Pre-cast Concrete (cladding fixings and connections), Brickwork and Other Elements with inherent cavities and voids:- Fixings, connections and ties have been available in a wide range of types, manufactured in a wide range of materials, including plastic / nylon, mild steel / galvanized mild-steel, alloy steels and stainless steel.  The above instruments, other than a proprietary wall tie detector, fitted with an appropriate detector-head, will be inappropriate for the detection of fixings, other than those manufactured from mild-steel / galvanized mild-steel.

Furthermore, even where fixings were manufactured from mild-steel / galvanized mild-steel detection limits, with respect to both depth and accurate positioning, vary significantly from instrument to instrument and generally, in our experience, resolutions deteriorate significantly with depths greater than around 100mm.  Furthermore, in some cases, congested reinforcement /contamination of the concrete with magnetic constituents can result in erroneous responses which can be, at best, difficult and misleading to resolve.

Therefore, at selected locations cavities or voids can be investigated using fibre-optical borescopes / endoscopes, inserted through small drilled holes.

NB:  Low or poor lighting within the cavities and the limited fields of view, together with contamination of the cavities with rubble and other debris will collectively limit the resolution of the fixings.

In cases where the above cannot satisfactorily resolve the required detail, or where further investigations are considered appropriate and safe, such investigations will be carried out, using small drills / breakers and hand-held tools used carefully to breakout and expose the hidden details.

To minimise damage and unnecessary breaking-out the results from the various covermeters and related scanners, ultrasonics, radar and borescopes / endoscopes can be interrogated and used to focus on particular ‘features’, which can then carefully be exposed by ‘keyhole’ breaking-out.  Once exposed, to the point where a ‘feature can be satisfactorily resolved, breaking-out can be halted, the detail subjected to direct inspection and measurement and the break-out made-good.

NB: Intrusions into a structural fabric although limited, both in number and size, to maximize the amount of information gathered, whilst minimizing the amount of disruption and damage caused will represent potentially ‘vulnerable-points’ going forward, regardless of making-good, until the structure has been subjected to appropriate repair and maintenance.