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Plowman Craven has 60 years’ experience providing integrated measurement and consultancy services to the property and infrastructure markets.

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0207 490 7700
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Structural, Geotechnical & Environmental Monitoring

Plowman Craven's structural, geotechnical & environmental monitoring services - plus a range of construction surveying and rail track monitoring services - are integrated with our broader surveying and measurement offerings throughout the project lifecycle, helping to save our clients valuable time and create efficiencies in our delivery.

With a strong management team, industry leading expertise and the resources of the Plowman Craven group, we are a market leader in the structural, geotechnical and environmental sector.

Our construction monitoring services are also fully integrated with Plowman Craven’s Environmental Planning division - for centralised installation, management and delivery of a complete package.

> Things to consider when defining a monitoring scheme.

Things to consider when defining a monitoring scheme

How do I know if my project requires a monitoring scheme?

It is not always straightforward to identify whether monitoring is required when undertaking construction works. However, here are a few questions to consider which may make the decision process more straightforward.

  • Is the project taking place adjacent to or above assets such as railway lines, tunnels, heritage buildings, utility services or other sensitive property? Is a rail track monitoring solution required?
  • Does the activity involve the excavation of a basement?
  • Do I need to comply with certain environmental legislation during the works, such as Section 61?
  • Could the work cause ground movement which may impact the stability of surrounding structures?
  • If making changes to an existing building, is structural integrity likely to be compromised? Is the activity likely to have a significant impact on ground water and would it be useful to understand conditions as the work progresses?

This list is not exhaustive and a positive answer to a question does not always indicate that monitoring is definitely required. It is certainly a good place to start, however, in order to understand whether further discussion with a specialist monitoring contractor is necessary.

When is the right time to start monitoring?

This is a question commonly asked and the natural response is always to suggest it should commence as early in the project programme as possible. Ideally, it is always preferable to understand how structures or ground conditions naturally change through seasonal variations, and then use this information to define a baseline for future comparison.

However, obtaining a baseline over the course of a year or more is rare and often unfeasible due to both programme and cost constraints.

The key is to ensure that monitoring is established well in advance of any works that might have an influence, to ensure that stable data is obtained. It is also important to liaise with any key project stakeholders, such as London Underground or Network Rail, to understand their requirements for baseline monitoring.

Collecting good quality baseline data is vital if observations and trends are to be understood during the works.

Do I need continuous automated monitoring or is a periodic manual regime sufficient?

Typically there is no ‘one-size-fits-all’ approach and each monitoring scheme should be considered on a case by case basis. However, here are a few questions you can ask yourself to establish which approach may be best suited:

  • How much risk is involved with the works and what assets are located nearby? A good example would be piling within the exclusion zone next to a live London Underground tunnel. This operation carries a very real risk on impacting the safety of critical infrastructure and therefore an automated, near real-time system would likely be required. Conversely, piling several meters away using appropriate methodology may carry minimal risk and LU may therefore be happy with monitoring taking place manually on a periodic basis.
  • How long will the monitoring be required for and how often is the data needed? For shorter schemes of a few weeks or months manual monitoring, where a survey team regularly attends site, might be a cheaper option. However, on larger schemes where the monitoring could last for years, it is likely to be more cost-effective to automate the monitoring, eliminating the need for costly site visits. This is also the case when more frequent data is needed to support activities that carry a higher level of risk. Increasing survey frequencies can dramatically increase the cost of a scheme over quite a short space of time, so again, an automated approach may be preferable.
  • What are the constraints in carrying out the monitoring? Whilst site activities may not pose a significant threat to surrounding infrastructure, and a manual monitoring regime would typically be sufficient, access restrictions may not make this practical. A good example is when carrying out rail track monitoring of live railways. Access to this sort of asset is typically only available during engineering hours and/or possessions and therefore the window for collecting data can be limited. There can also be significant costs involved in obtaining possessions which can greatly increase the total cost of a monitoring scheme.

Plowman Craven regularly works with clients who are considering either manual and/or automatic monitoring techniques and we are always happy to talk through the benefits of each approach. We also frequently provide unbiased cost comparisons so that the appropriate informed decisions can be made.

Are there any sources of information that would help me define a monitoring scheme?

Over the last few years, a number of excellent resources have been created which help to both define and specify monitoring schemes. Whilst they should always be backed up by expert advice, these are a great place to start when trying to understand best practice and how monitoring can benefit a project.

A couple of our favourite examples can be found via the following links:

  1. The Survey Association - Guide to Instrumentation & Monitoring
  2. BSI BS EN ISO 18674 Series

What information can a monitoring scheme provide?

Ultimately, the main reason monitoring is required is to determine whether certain parameters are deviating away from their normal state. This might be the rotational movement of a retaining wall, an increase in pore water pressure or an increase in noise and vibration levels in comparison to ambient conditions. This in turn provides assurance to stakeholders, informs engineering decision making and ensures compliance with relevant obligations.

Therefore, the key to determining what monitoring is required and what equipment is to be used is to first identify the question you are trying to answer. It is not uncommon to see specific monitoring approaches or equipment included in specifications that will not provide results to validate the parameter in question. This can lead to misunderstandings when interpreting the results and, in extreme cases, compromised decision making. Always start with the problem and work backwards.

Another thing to consider is that the type of data that can be provided through monitoring regimes continuously changes.

Over the past few years a number of extremely innovative businesses have begun offering new monitoring products to the industry and they continue to develop them at a fast-moving pace. New advances allow parameters to be measured in ways that were not possible previously, providing more meaningful data in a greater range of situations.

Added to this are the benefits that improved data interpretation and analysis capabilities bring. It is becoming more and more common for monitoring data to be augmented and post-processed in a way which provides additional insights to clients, therefore speeding up the decision-making process. Design assumptions can now be validated at an almost real-time pace, increasing safety and opening up the potential for constant optioneering throughout the construction process.

At Plowman Craven, we are passionate about the possibilities new technical approaches can bring and we are always happy to share our thoughts with others!

Structural Monitoring

Ensuring all buildings and surrounding structures remain stable during construction is a critical challenge for developers undertaking major projects, with precise monitoring and early warning of movement a necessity.

Our consultative and expert approach minimises risk and creates programme efficiencies.

Having worked on many major tunnelling and construction developments, we’re experts in the measurement and monitoring of deformation, deflection and settlement during demolition, excavation and construction works.

We monitor for Heave/Settlement, Distortion and Deformation in real time using web-based display and alert software. We are passionate about data visualisation and continuously strive to provide meaningful insights to our customers.

Geotechnical Monitoring

Comprehensive monitoring schemes will consider not only the protection of assets but will also provide data to support geotechnical design. Our team is highly experienced in monitoring ground movement during construction as well as the various techniques used to monitor changes in ground water conditions.

We have access to a number of Ground Investigation suppliers and regularly work with them to install instruments such as extensometers, inclinometers and piezometers. These instruments can be manually read or linked to bespoke data acquisition systems in order to provide near real-time measurements via our web-based data visualisation software.

Our instrumentation systems can also be used for detecting movement during excavation by incorporating sensors into piling and propping schemes.

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Construction Surveying

The importance of establishing and maintaining an accurate and robust survey control is a project fundamental and translates to topographic survey/BIM modelling in the early stages, setting out, monitoring and as built surveys during the construction phase.

Positional control during construction works is key to a successful and error-free project, particularly when verifying accuracies in the construction of pre-fabricated, modular tower blocks.

Plowman Craven can offer all of these services with an onsite survey presence throughout the project life cycle, ensuring the all-dimensional surveys are referenced to the same assured control grid and eliminating discrepancies.

Services include: Control Establishment & Verification, Grid Lines & Datums, As-Built Surveys, Window Alignment Surveys

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Condition Surveys

Condition Surveys delivered by Plowman Craven present an accurate recording of the existing condition of a building or surrounding area.

The recording of the condition of buildings or structures assists in identifying costs for repairs, maintenance and improvement works prior to the acquisition, disposal or occupation of a property. It also helps to determine a scope required to enable fit-out works, and assists in protecting an individual or company’s interests prior to and after development.

We provide condition surveys and schedules of condition for a variety of property types including (but not limited to) office, retail, light industrial, and railway premises and structures.

Correlation, Utilities and Gauging Surveys

When a development involves piling or other sub-surface works, it is essential that the geospatial relationship of items both above and below ground is determined to a high degree of accuracy and reliability.

This complete geospatial correlation helps to mitigate risk and assist in the avoidance of major disaster, considerable cost implications, reputable damage and construction delays.

Plowman Craven works closely with developers and underground asset owners to deliver precise correlation surveys for projects where Network Rail and London Underground assets are present.

In addition, our specialist in-house utilities division uses the latest technology to trace, identify and map all underground utilities and service routes including gas, water, telecoms, electricity and drainage.

How Can We Help?

Let’s discuss your requirements and see how our expertise can help on your next project.

Plowman Craven has 60 years’ experience providing integrated measurement and consultancy services to the property and infrastructure markets.

Jay Holland Plowman Craven

Talk to our expert

01582 765566
jholland@plowmancraven.co.uk

James Holland

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