Technical
EFFC/DFI Guide to Tremie Concrete for Deep Foundations 3rd Edition
This is the 3rd Edition, published December 2024, providing authoritative guidance on the placement and testing of tremie concrete in deep foundations.
It is intended that the guide is used by contractors and concrete suppliers to improve the quality of concrete used in deep foundations. Historically there has been limited research and understanding about how concrete behaves in the ground, which has led to problems onsite as concrete mixes became more complex with the addition of admixtures, additives, aggregates etc.
The new edition incorporates field studies of concrete taken from construction sites in Europe and the US to provide an empirical testing criteria for the acceptability of fresh concrete. The guide’s data has been collected by the Technical University of Munich and the Missouri University, using an agreed methodology that includes a range of onsite and laboratory testing.
The guide now has recommendations on which tests should be used to determine the workability of the concrete. This is particularly useful on site, where construction teams can determine with a high degree of accuracy whether the concrete will work as intended within the pile or diaphragm wall.
In addition, the Guide incorporates work that numerically models the behavior of concrete when it is poured into an excavation. This is a new area of research which provides new insight into what is occurring during the tremie operation.
The Guide is a collaboration between the DFI in the US and the EFFC, and is a piece of work that is intended to benefit the global deep foundations industry.
EFFC-DFI Support Fluids Guide
The European Federation of Foundation Contractors (EFFC) and Deep Foundations Institute (DFI) have produced a comprehensive guide for the use of support fluids in deep foundations. The first edition of the Guide aims to represent the state-of-the-art of support fluid practice. It aims to improve the existing design, testing and practices for elements such as bored piles, barrettes and diaphragm wall panels. The Guide brings together knowledge and expertise from around the globe into a single document for the first time and is the first step towards establishing a global standard.
A research and development exercise is to follow that shall seek to to carry out a series of Field Research Studies (FRS), which will collect data from active project sites and develop and conduct non-standard tests in order to establish what testing methods have substantial value and to better understand the validity of the compliance values in use. Specifically, the FRS will be split into three parts; obtain contractor’s standard test data sets from about 40 sites; develop non-standard test methods and obtain data sets from about 20 sites by independent specialist visits; and work with academic partners carrying out related studies. The FPS are actively supporting the Support Fluid Task Group that is putting the Guide together and conducting the FRS.
Safe Lifting of Reinforcement Cages
Following several incidents when lifting reinforcement cages, the FPS and BAR (British Association of Reinforcement) have collaborated to produce a guidance note. This outlines current best practice in relation to the design and lifting of pre-fabricated reinforcement cages and site fabricated reinforcement cages for piling and walling works.
The document covers the provision of cage design information; information required on the purchase order; delivery and lifting on site; and quality. Two safety checklists (one for piling cages and one for diaphragm wall cages) are also provided.
Electronic Bearing Pile Schedule
The FPS has produced an Excel based spreadsheet to assist with the provision of pile design schedules. Structural Engineers should use this document and guidance to provide the piling contractor with the information they need in order to produce a cost-efficient, appropriate design. If information is not provided in this way there is significant potential that the resultant piling scheme far exceeds the needs of the project. Please contact the FPS if you need further guidance on how to use the e-pile schedule – fps@fps.org.uk
FPS E-Pile Schedule to EC7 Version 4 0 2018
PS Eurocode ePile Schedule Guidance Note – Rev 3 – 24 04 2018
Site Investigation
FPS Survey of Site Investigation Reports
This document reports the results of a survey of over 200 projects carried out between July and September 2006 and highlights many shortcomings in the quality of Site Investigation Reports.
Published Minimum Requirements for Site Investigation
This document is a list of excerpts from published sources on the subject of minimum requirements for a site investigation.
Pile Testing
Information on Pile Load Testing
Links to our advisory note on different pile integrity testing methods, the Handbook on Pile Load Testing and FPS Datasheets on Pile Load Testing
Review of pile integrity testing methods
Safety in Design
Use of Debonding Foam
Technical considerations related to the use of debonding foam on pile reinforcement.
Use of Debonding Foam – Technical Considerations
Breaking Down of Piles
The adoption of a suitable pile breaking method can result in financial and program savings and, most importantly, will address and reduce potential health and safety issues. In this document, the FPS consider the different methods available.
Breaking Down of Piles (FPS) -May08
Safety in Design
Guidance on the application of CDM 2007 to pile foundations and embedded retaining walls, and examples of hazards associated with such works and how these might be managed within the design phase of a project.
Other Guidance
FPS Guidance: CFA Piling: Preventing ground & rig instability through over-flighting
The guidance outlines the key factors that may lead to settlement or instability of the piling rig when carrying out Continuous Flight Auger (CFA) piling as a result of over-flighting and presents best practice to mitigate these risks.
CFA Piling Preventing ground rig instability through over-flighting FINAL
Design of Piles to Eurocodes (Position Paper)
Design of Piles to EC2 and EC 7(position paper)- Nov11
Design of bored piles in chalk
FPS Position on the use of CIRIA Report PR11.
Bentonite Support Fluids
Information to assist the decision whether or not a particular bentonite will produce a satisfactory support fluid. Guidance on the preparation, use, re-use and disposal of the bentonite slurry, and also on methods of testing.
Unexploded Explosive Ordnance (UXO)
The legacy of unexploded explosive ordnance (UXO) occasionally leads to problems on construction projects in the UK. These problems have led to delays and increased costs, especially during the groundwork phases of construction. The CIRIA guide “Unexploded Ordnance (UXO) – a construction industry guide” presents industry best practice for the assessment and management of UXO risk for construction projects. This note summarises some aspects relevant to piling and ground improvement contractors.
Unexploded Explosive Ordnance (UXO)
FPS Reference Material – Temporary Works
The aim of this document is to provide a simple summary of temporary works items that are commonly associated with the various forms of ground engineering that FPS members may undertake. This is designed as an aide memoir for FPS members, main contractors, engineers and their clients and does not constitute a definitive list of temporary works that could be encountered on site. In particular this does not remove the need for individual organisations to undertake site specific assessments of temporary works requirements. Statutory legislation and the Contract will define the respective responsibilities of the parties involved to manage the design and checking of temporary works.
Self-Drilling Hollow Bar Systems, Grouted Ground Anchors, Micropiles and Soil Nails: Application, Benefits and Limitations
Guidance Note on Self-Drilling Hollow Bars Grouted Ground Anchors Soil Nails Tension Piles
This note provides an overview of self-drilling hollow bar systems, grouted ground anchors, micropiles and soil nails, their application, benefits and limitations, together with comment on their design as tension elements in the UK. All of these elements have their place within the design and execution of stabilisation or foundation works however their performance characteristics and durability considerations are different. Key features of the different systems are highlighted.
Technical Note on the Corrosion of Pile Reinforcement Cages
FPS Guidance Note on Corrosion of Pile Reinforcement Cage
This note provides an overview of the provision protection to extended bars against corrosion, relating to the use of the main bars of the pile reinforcement cages being used as ‘feet’ to provide the required concrete cover to the main cage, and support the installed cage, giving some flexibility to the bore depth. The note provides examples of measures which can be take to avoid corrosion occuring.
FPS Guidance Note on Considerations for Specifying Crosshole Sonic Logging Test
FPS Guidance Note on Considerations for Specifying Crosshole Sonic Logging Test
In accordance with their duty under Construction Design and Management Regulations, specifiers must eliminate, substitute or reduce safety risks and must do this when specifying CSL. This can be achieved in the following ways; CSL should be avoided in dry stable rotary piles and small diameter piles where the sonic logging tubes have <300mm clear separation. Consider alternative integrity testing methods. Where CSL must be used, limit its use to the top of the pile within a single cage length to eliminate the need to splice tubes, reduce testing frequency, limit the number of tubes (tube spacing as great as 1.5m is acceptable) and where applicable reuse inclinometer or base grouting tubes.