Inspection
Before any repair is undertaken it is necessary to establish the cause and extent of deterioration through an investigation of the structure. Without this the use of inappropriate repair materials and methods could lead to additional problems later on. With experience gained from the survey of hundreds of structures, and a practical approach, our team is able to minimise survey time and expense.
Survey Planning
Establish Client Requirements
We use our expertise to advise the client on appropriate testing depending on the outcomes sought, safety requirements, and commercial aspects that may affect his business.
Review Exposure
We quickly establish the exposure by reviewing design, construction and operational activities (past and present).. In many cases the important parameters are immediately obvious (e.g. in splash zones of marine structures the problem is probably chlorides) while in others a cursory evaluation could be misleading.
Design Analysis
Clues to the cause of deterioration can often be found in the design. For example tension regions may have micro-cracking and have poorer penetrability. It is important to understand how the structure is working if critical areas are to be identified.
Construction Assessment
In some cases construction assessment goes far beyond looking at detailing (e.g. construction joints). It may be necessary to review materials used (e.g. contaminated aggregates), establish seasonal influences (e.g. effect of curing) and review techniques used (e.g. compaction).. In some cases it may be necessary to review construction records and discuss the method used with the contractor or owners representatives.
Survey Preparation
Logistical planning is critical to the success of surveys.
In some cases it may simply be a case of walking up to the surface and making observations, in others erecting access and catching a short weather window at a remote location may all but be impossible. Our survey managers have planned surveys from the North Sea to the remote regions of Northern Australia and can ensure the work is undertaken with the minimum of down time.
From the design and construction review the survey programme is drawn up detailing who will undertake what work and how they will be supported.
Inspection & Testing
Our survey managers are expert in sampling, non-destructive testing and laboratory analysis. As such they manage the inspection and testing programme.
Visual
Proforma, prepared in the planning stage, are used to show significant design or construction features. Standard classification systems are used for classification of reinforcement corrosion extent and concrete defect type and size.
Sampling
We know how to take samples to minimise the risk of contamination, ensure adequate sample size and statistically identify sample locations.
NDT’s
Our experts have been involved in non-destructive testing for over 20 years. In some cases they were involved in the pioneering development of some of today’s common test. Test methods that we commonly use (see pictures below) and can provide methods statements on include:
- Visual inspection, including crack measurement (width and movement) and remote viewing, eg binocular or video (P1-5).
- Corrosion surveys including
- Reinforcement electrical potentials using rapid scan Canin and potential wheel (P7)
- Carbonation and chloride penetration site test (P8)
- Concrete resistivity for corrosion rate (P9)
- Corrosion rate by linear polarisation (P12) and logging using embedded probes (P10 & 11)
- Cover survey using logging scancar (P13
- Concrete assessment including
- Pendulum hammer 1-10MPa strength test (P14)
- Digital Schmidt hammer tests (P15)
- Karsen tube absorption test for concrete quality and coating effectiveness (P16)
- Impact echo impulse response for internal defects & concrete (P17) thickness
- Radar (GPR) for location of deep reinforcement (including prestressing), buried objects & prestressing
- Thermography for location of delaminations
- Pull off testing for veneers, overlays, carbon fibre strengthening, coatings & shotcrete (P18)
- Extraction testers (P19)
- Concrete sampling by coring, jack hammering and dust collection (P20-24))
Monitoring
In some cases the structures condition cannot be immediately determined as load or environment can have cyclic effects. We can determine the appropriate monitoring systems and manage installation, monitoring and assessment. Systems readily available include linear polarisation, potential cell and rack probes, strain gauges and temperature measurement.
Assess Results
In many cases the cause of deterioration is simple to establish. However, secondary effects can have significant implications on the long-term prognosis. It may be necessary to undertake a range of check tests to determine if mechanisms other than the obvious are occurring.
The survey should establish the extent of deterioration so that the most effective repair method can be prescribed. In some cases spot testing in the various structural and environmental zones provides sufficient information. In others detailed mapping is required.
Future Prognosis
The survey results also establish the rate of decay so that an estimate of future deterioration can be made.
Structural Status
In some cases deterioration is relatively unimportant while in others it is critical. We work with associates to provide a structural analysis.
Appropriate Reporting
We pride ourselves on our practical approach to consulting. This means that reporting is appropriate to the clients needs for each projects. In some cases this could mean that the analysis is conveyed to the client along with the survey records. In others, such as litigation fully detailed reports are provided.
Benefits of Our Services
Expert input from durability, concrete, inspection and repair specialist consultants. Inspection is undertaken quickly with pragmatic approach to detailing repairs.