With the government’s systematic easing of lockdown restrictions many people are visiting key tourist destinations within the UK. The Eden Project is an attraction in Cornwall, England, UK and has been on Dr Mothersille’s list of places to visit for many years. The project is located in a reclaimed china clay pit, located 5 km from the town of St Austell.
The complex is dominated by a series of huge enclosures consisting of adjoining domes, up to 55m high, that house thousands of plant species. The largest of the two domed structures simulates a rainforest environment (and is the largest indoor rainforest in the world) and the second, a Mediterranean environment. The attraction also has an outside botanical garden which is home to many plants and wildlife native to Cornwall and the UK in general.
The site required stabilization of the boundary quarry faces and tying down the foundation ring beam using double corrosion protected ground anchors. The stabilization of the quarry faces involved the installation of over 2,000 rock bolts and soil nails up to 11m long.
During a recent visit, Dr Mothersille spotted additional rock bolt installation works in the peripheral rock faces around the pit.
What started as a fascinating trip to photograph an extraordinary collection of plant life ended with an interesting view of active rock bolt installation works!
The Engineering Management Institute (EMI) is an organisation that provides engineers of all experiences with career and personal development information to help them succeed in work and life. The EMI currently publish a podcast called ‘The Geotechnical Engineering Podcast’ (TGEP) through which they try to provide information to help listeners succeed.
TGEP invited Dr Mothersille to participate as a guest speaker to describe his career path, life choices and areas of expertise.
The podcast went live in May 2021; the YouTube link is given below. Enjoy!
Representatives from the Institution of Civil Engineers Yorkshire and Humber division invited Dr Mothersille to deliver a presentation on grouted anchors to the Yorkshire Geotechnical Group. Following months of negotiations and planning, due to competing existing commitments, the talk finally took place on 13th April 2021 and was successfully delivered to a virtual audience.
Through a valued collaboration with the USA division of the Deep Foundations Institute (DFI), DFI India has organised a series of webinars developed for students in civil engineering with particular interests in geotechnical engineering; the initiative is DFI India Student Outreach Program ‘Groundwork’.
Following an invitation by DFI (USA), on 16th March 2021 Dr Mothersille delivered a 40-minute lecture on ground anchors followed by a 10 minute Q & A session. The talk covered definitions/terminology, exploring the concept, worldwide applications, design, corrosion & corrosion protection, construction and testing (including the innovative AnchorTestTM technology for data processing and analysis). Finally, Dr Mothersille presented a case history detailing the raising of Hazelmere dam in South Africa. This example usefully demonstrated many of the aspects covered in the webinar on a unique project.
The session included an excellent 20-minute presentation from Ms Jewels Stover (Nicholson Construction) entitled ‘The Art of Negotiation’. The attendees included students, academics and practising engineers from all over India who would have certainly derived considerable benefits from these two subject areas.
Special thanks are due to Ms Mary Ellen Large (Director of Technical Activities, DFI, USA) for recommending Dr Mothersille to be a speaker at the event, Mr T Rambabu (UR Ground Engineering Pvt Ltd) for acting as session moderator, and Mr Pranav Jha (Assistant Manager, Operations, DFI India) for coordinating the IT aspects on the day.
Towards the end of 2020 the Nigerian Society of Engineers (NSE), UK branch invited Dr Mothersille to deliver a presentation to its membership covering his area of expertise. In January 2021, Dr Mothersille gave a presentation entitled ‘An Introduction to Ground Anchor Technology’. The presentation’s objective was to provide the audience with an insight into ground (grouted) anchor technology, initially defining terms and exploring the concept and then showing a variety of applications by drawing on examples from a worldwide database. After briefly covering some basic implementation features, a case study was described that captured several world firsts concerning ground anchor usage. By the end of the session, there was no doubt attendees gained an improved fundamental understanding of how ground anchors are applied, designed, constructed and tested.
The event was declared a resounding success by the President of the NSE, Dr. Sunday Popoola. The audience’s enthusiasm was proved by the fact that the Q & A session, convened afterwards, lasted longer than the 50-minute presentation itself!
It has been years in the making, but finally, a book deal is agreed with internationally renowned publisher Taylor & Francis Group. The textbook, scheduled for completion in summer 2023, is entitled ‘Grouted Soil and Rock Anchors’.
The book is aimed at consulting engineers, contractors; civil, structural and geotechnical engineering students and even asset owners, who during their activities, propose or encounter the use of grouted anchors. These geotechnical installations have been used worldwide to support various types of structure. Over time, millions of grouted anchors have been installed successfully ranging from systems of a few tonnes capacity in small retaining walls to pre-stressed tendons of several thousand tonnes capacity to resist direct tension, sliding, overturning and dynamic loading in dams. Other applications include stabilising deep excavations, bridge abutments and several different forms of geotechnical structure.
Anchors have established a permanent place in construction practice, but for engineers and asset owners not yet thoroughly familiar with modern anchoring technology, conventional and potential applications will be outlined to provide some perspective and encourage further exploitation.
The book is structured around the key areas of design, construction, testing and service behaviour performance. In addition, maintenance inspection, condition assessment, innovative applications and current research will be addressed. In recent years standards and codes of practice have undergone significant changes, particularly in Europe, and these essential developments will also be covered.
Dr Devon Mothersille is the lead author with highly respected co-authors Dr Donald Bruce (USA) and Professor Stuart Littlejohn (UK). The authors have collectively compiled over 120 years of experience and published hundreds of technical papers and articles covering various aspects of geotechnical engineering with particular reference to ground anchoring practice. Their collective expertise has been developed from direct input into projects all over the world, academic and industrial research, and dedicated participation in various committees associated with the development of standards, codes of practice and best practice guidance documents.
November 2020 has seen the publication of the new CIRIA report C794 entitled ‘Grouted anchors and soil nails: inspection, condition assessment and remediation’. This unique document fills a gap in the current literature, where there is limited guidance on this highly specialised area. It will undoubtedly assist asset owners, designers, contractors and others involved in the condition assessment, planning and execution of the works, including monitoring, maintenance, remediation, repair and replacement of grouted anchors and soil nail structures.
The drafting of C794 was a team effort. CIRIA awarded the contract for the work to the geotechnical engineering consultancy Gavin & Doherty Geosolutions Ltd (GDG). Following reviews from a project steering group, comprising some 20 individuals, GDG engaged the services of Mr Chris Irvin (Dywidag, UK) and Dr Devon Mothersille (Geoserve Global Ltd and Single Bore Multiple Anchor Ltd) for specialist input as technical authors.
The Covid-19 pandemic demanded that the launch event for C794 took place online, and this was judged successful with some 85 participants attending. The technical authors delivered four presentations covering the following:
Introduction and background
Grouted anchors: Condition assessment and remediation
Grouted anchors: monitoring and maintenance
Soil nails and soil nail structures
The presentations were followed by a question and answer session that allowed members of the audience to clarify points of interest and gain more detail on specific areas.
AnchorTestTM is an innovative Cloud-based software package, specifically developed for tablets, that permits anchor test data assessment and management in real-time. The solution has two components: a front-end tablet app runs on the Apple iPad platform, and a back-end Cloud-based system running on Amazon Web Services with an online cross-platform website, which can be accessed from any PC, tablet or even mobile smartphone. This tool provides full data analysis and data management capabilities and portability to create greater efficiency in the anchor testing process. AnchorTest is programmed to accommodate the major international anchor testing codes and incorporates a revolutionary, intuitive user interface. The use of this tool creates an environment where the testing of grouted anchors has effectively become a paperless exercise, with access to instantaneous feedback on the performance of the anchors in relation to established acceptance criteria.
The Qatar Petroleum multi-storey car par project involves major deep excavation works incorporating removable single bore multiple anchors (SBMAs). These anchors are unique in that although they are removable, they are classified as permanent since a ten-year design service life was specified by the structural designers. The anchor tendons were designed by SBMA Ltd and manufactured by DeCa srl in Italy before being shipped to site in Qatar.
The mandatory acceptance testing of the production anchors is currently underway, and the use of AnchorTest has allowed specialist foundation contractor, Bauer (Qatar), to operate with improved efficiency by reducing time and costs.
SBMA Ltd, in collaboration with its certified tendon manufacturer DECA srl, have been awarded the contract to implement removable anchors for the Maggoire Policlinico Hospital in Milan, Italy. The deal involves the design, manufacture, supply and supervision of the removable anchors which will form an integral part of the foundation support system.
The SBMA removable anchor technology will be the first of its type to be used in Italy and represents an exciting opportunity for the company. The anchors are to be installed in alluvial deposits, typically comprising sands and gravels and have working loads ranging from 410kN to 700kN.
To improve the understanding of this pioneering technology, the main contractor (SIS SCPA) and specialist anchor contractor (Palingero) were invited to an impressive demonstration at the DeCa factory in Genoa. Delegations from these organisations attended the demonstration which featured a full-scale removable anchor tendon being removed from a simulated borehole after being stressed and locked-off.
Travel restrictions imposed by the Covid-19 pandemic presented challenges for Dr Mothersille attending the session; however, these were overcome by using the Facetime facility on iPhone. Using this feature, Dr Mothersille was able to participate in the demonstration and discussions in real-time. Once again, this demonstrates how innovative thinking and technology can be utilised to adapt to and overcome the difficult circumstances the industry currently faces.
A trial anchor programme is scheduled for commencement in the coming weeks.
iPhone screen shows Dr Mothersille (insert) participating in discussions in Italy from his office in the UK
iPhone screen shows Dr Mothersille (insert) participating in a factory demonstration in Italy from his office in the UK
Craig Goch Dam is a masonry gravity structure built between 1897-1904. The dam is 36.5 m high above the river bed, 119 m long, 32 m thick at the base and the foundation extend 3 m below the river bed. Craig Goch reservoir has a capacity exceeding 9 billion litres covering an area of 217 acres. The primary purpose of the dam and other reservoirs in the area is to supply Birmingham with water.
Purely for intellectual interest, Dr Mothersille and his 26-year-old son Reiss visited the structure and were fortunate enough to witness it spilling and conveying thousands of litres of water downstream.
Dr Mothersille and son, Reiss, enjoy the spectacular views of water cascading over the spillway at Craig Goch dam