The need, quality and sufficiency of site investigations has been of paramount importance since the early 1960s and the issue of client awareness of the benefits of site investigation have been well-discussed within construction industry.
In the late 1950s, Foundation Engineering produced the film “The problem below” to address this issue. The film described and projected the need and benefits of carrying out site investigations. A project in Boness in Scotland was selected for filming.
I recently saw this film again for the first time in about 20 years. Although the aircraft at Glasgow Airport was a Viscount turbo prop and the drilling rig a Conrad “slip rope” rig (with square boring rods and tools), the requirements for quality, sufficiency, client understanding and “buy-in” were well portrayed and appeared to be well understood.
Today’s clients are more likely to develop a project and move on as fast as possible to the next one, with many (if not all) the responsibilities and liabilities being devolved down the supply chain to architects, consultants and builders, by the use of sometimes onerous terms of engagement, including multi-assigned warranties. In dealing with these clients, the ground is generally taken for granted. When projects involve the redevelopment of brownfield sites the concerns of contamination and perceived high risk associated with this seem to become more evident, however.
Local planning authorities’ requirements and stipulations for such sites generally ensure the client and their team consider the geoenvironmental issues at pre-planning submission stage. The desire to obtain planning permission and the need to tackle contamination risk issues act as drivers for undertaking geoenvironmental investigations. In many instances however, the initial site investigation ignores some of the main geotechnical issues. How often is a geoenvironmental site investigation – which usually does not even include the most basic insitu geotechnical tests such as a standard penetration test – offered to a piling contractor for them to design, price and carry out foundation work?
When clients are in the early stages of conceiving a project they need to establish a funder, insurer and a project management team as well as the usual engineering consultancy service providers. The consultancy service providers called upon in the initial stages are generally architects and structural engineers, who usually may only see the above ground structure. The introduction of the geotechnical adviser into a project team at an early stage has been strongly advocated over the past ten years by the Institution of Civil Engineers and Association of Geotechnical and Geoenvironmental Specialists (AGS) but in many cases this is not happening.
The structural engineers in some instances see themselves as capable of undertaking this geotechnical role or are unaware of the good practice guidelines laid down by AGS and others. To address the situation and develop more client awareness, the industry needs access to the commercial team. To this end, AGS will shortly be completing its project benchmarking scheme, which will provide an assessment and score for each project where there is ground engineering site investigation input.
The scoring system is based on Key Performance Indicators (KPIs) for the particular geotechnical activities undertaken within ten selected groupings, including one for client satisfaction. This initiative is likely to eventually provide a substantial database of assessed projects, which can then set the norm for good, moderate and poor site investigation input. Information from project benchmarking and KPI scoring can also be developed to provide the client’s commercial team with a simple “traffic light” risk assessment of the project. It will then be simple to show the benefits of carrying out a full ground engineering site investigation service – desk study, phased intrusive ground study, associated supervision, laboratory testing and ground engineering advice.
The AGS and Federation of Piling Specialists recently had discussions concerning the quality and sufficiency of site investigation reports provided to foundation contractors, and agreed to consider a joint advisory paper, likely to be called “Guide to foundations”, published as part of the AGS Clients Guides. CDM regulations are also expected to be included. AGS members recognise the need for the Site Investigation Steering Group (SISG) series of publications to be redrafted and published as soon as possible, as the 1993 editions are well out of date. There are plans within the fraternity to arrange for the SISG Specification (Yellow book) to be redrafted within the next year or so.
Jim Cook is chairman of the Association of Geotechnical and Geoenvironmental Specialists and director of Buro Happold’s Ground Engineering group.
The following article originally appeared as a ‘Talking Point’ in Ground Engineering, June 2005.