The need for better site investigation

Philip Hines argues that poor site investigation information is almost worthless when it comes to designing a cost-effective piling solution.



Few would argue that effective site investigation is not only best practice but essential for identifying ground conditions that may have the potential to impact negatively during the proceeding construction phase of any project. It is also widely accepted that any failure to identify ground issues often results in unforeseen costs to the project, as well as that all too familiar issue of late completions. However, what is often overlooked is site investigation's ability to save money, as any subsequent ground engineering work, such as piling, can be effectively matched to the ground conditions and not guessed at or ‘over-engineered' to simply avoid future unknown issues.

Despite the proven cost-effectiveness of undertaking a proper site investigation and the many compelling arguments to support it, members of the Federation of Piling Specialists (FPS) are reporting that, increasingly, the quality of site investigation data they are being provided with is still often well below the standard required to produce an economical pile design.

Poor site investigation information is almost worthless when it comes to designing a cost-effective piling solution, and FPS members are too often having to make assumptions, which may be conservative, therefore leading to an over-engineered solution or optimistic leading to issues during construction, resulting in delays and claims. Optimistic solutions may appear attractive at the project outset but generally, lead to higher client costs.

Typically, testing carried out during site investigations is the cheapest onsite testing rather than more accurate laboratory testing. It provides testing information that varies widely and can be open to different interpretation. The technique for undertaking investigations is also too often driven by cost rather than ground conditions. This leads to poor sample recovery or inaccurate groundwater information. Quite simply, clients are still under-investing in site investigation to save money without considering the bigger picture and the benefits that quality site investigation data can add to a project.

The FPS is currently quantifying the quality of site investigation typically received, with a view to producing clear and concise guidance on the minimum site investigation information required for effective piling solutions.

For piling contractors, having access to high-quality site investigation data at the right time in the project development can mean certainty in a reduction in pile size, a reduction in concrete use and even less time on-site, which beyond the obvious economic savings can also bring environmental benefits too - a win-win scenario.

Transmitting the correct site investigation information is also critical. Nearly all site investigation information is recorded in AGS format, however, this information rarely gets communicated through project supply chains in a timely manner. AGS data allows large amounts of site investigation data to be quickly analysed and assessed. It is critical to ensure this information flows through the project supply chain and forms part of the project digital data set. With the development of BIM (Building Information Modelling) and digital data management on projects, this should allow a step change in communicating AGS data.

Construction companies all boast about the need for quality and how much value they place on this over straight cost, yet the reality is often what specialist contractors (such as piling) face on almost all projects - lowest cost wins. While skimping on site investigations up-front can save clients a few pounds it increases project costs and, in some cases, it even puts the project's entire viability at risk.

It is time that all clients fully realise the benefits of procuring proper and thorough site investigations. The standards are there, laid out clearly and endorsed by organisations such as The Association of Geotechnical and Geoenvironmental Specialists (AGS) and British Drilling Association (BDA) and as an industry, we must all lobby hard to ensure we arrive on site in receipt of meaningful site investigation data that allows us to do our job effectively and for the good of all… cost effectively!

Phil Hines is the chair of the Federation of Piling Specialists