Partner Article

Why Site Investigations Are Important

Site Investigations (sometimes referred to as Ground Investigations, Geotechnical Assessments or Geo Environmental Assessments) are detailed, intrusive sub surface examinations carried out to determine the ground conditions beneath a proposed development site. A lack of knowledge in respect of the ground conditions can be one of the biggest risk elements in the development of concepts and budgets for a project. It can manifest itself as a huge cost impact if the ground beneath a particular site proves to be problematic. The site investigations will report on the engineering and environmental considerations related to a proposed development, as well as the profile of the sites naturally occurring soil and mineral deposits. This information is essential to understand the geology of a proposed site for development or redevelopment, to ensure the appropriate budget, design, planning or remedial works are taken into consideration before any construction begins. Why commission a Site Investigation and what does it entail? Site investigations are an essential part (and often a statutory requirement) of most civil engineering projects, regardless of size or scope. The site investigation report will, for example, provide information to:

• Specify suitable construction techniques

• Investigate and evaluate the safety of any existing structures and specify any remedial

measures (if required)

• Design and specify the depth and type of foundation required for a building or

structure

• Estimate and resolve potential problems with the foundations

• Determine the grounds bearing capacity

• Decide upon the suitability of the ground/soil as a construction material

• Estimate the maximum and differential settlements

• Determine the properties and levels of ground water

• Estimate the lateral earth pressure on retaining walls

Site Investigations are particularly useful if a proposed site is brownfield (i.e. has been previously developed and is potentially contaminated), greenfield or contaminated.Contaminated land contains substances that are (or potentially are) a hazard to public health or the environment. Here, site investigations (producing a contaminated land assessment) will be used to evaluate the potential of the contamination and highlight any remedial actions required to manage and mitigate any associated risks. Site investigations are usually requirements when planning civil engineering projects including industrial, commercial or residential developments, infrastructure projects (i.e. highways, rail, tramways, bridges or tunnels) or as part of land sales (pre-purchase) as part of the due diligence process. Development funding is often subject to the risk in the ground being understood, valued accurately and validated by a comprehensive and warranted site investigation.

A site investigation may be commissioned by a variety of professionals or organisations for

example:

• Building surveyors

• Design and Build contractors

• Commercial and residential developers

• Housing Associations

• Government Agencies

• Local Authorities

• Solicitors

Site investigations are approached in a variety of ways (dependant on your consultant or the project) however a phased approach, including desk research and study, site sampling and analysis, design of remedial strategy (if required) and monitoring and validation of remediation is commonplace. Site investigations can entail:

• On site coring (including cable percussion and rotary)

• Trial pit excavations

• Window sampling

• Dynamic probing

• Standard and cone penetration testing

• Soakage testing

• In-situ or field testing

• Unexploded ordnance risk assessment

• Groundwater monitoring

• Ground gas monitoring

• Laboratory analysis

Site Investigation v Ground Investigation

The terms ‘ground investigation’ and ‘site investigation’ can have different meanings to different people or organisations. Ground investigation is often more restrictive, producing specialist geotechnical information from intrusive geotechnical investigation and site monitoring whereas site investigations are often more in depth and involve desk study, appraisal of site data, assessment of the ground conditions (including geotechnical information) and the production of an interpretive site investigation report. Detailed site investigations are an essential part of modern civil engineering practice and whether commissioned by surveyors, contractors or developers or commissioned as part of the due diligence process of land acquisition, site investigation reports, performed by fully qualified professionals, can be relied upon to provide vital information, steering to inform the civil engineering and construction process. Alan Wood & Partners operate throughout the UK and have a dedicated, experienced and qualified site investigations team who’s specialist expertise covers a wide range of civil engineering disciplines, producing detailed and informative site investigation reports on behalf of clients in a variety of sectors.

This was posted in Bdaily's Members' News section by Alanwood .