Winner of the Inaugural LECA® Integrated Design Project - University of Leeds

University of Leeds University Winner of integrated Design

LECA® UK are delighted to announce that the winner of the LECA® Integrated Design Project Award is George Marchant. In conjunction with the structural engineering department at the University of Leeds, we are pleased to confirm that his technical report on an ambitious development of Fulham FC’s Craven Cottage football ground was the winner of this prestigious award - judged on its innovative ideas and intricate understanding on common issues facing structural engineers when increasing stadium capacity and developing an underground car park. This report successfully tackled common geotechnical issues facing designers when developing retaining walls including key factors issues such as variable loads, soil parameters, flood water management and lateral stability. 

Q&A with George Marchant:

1.       Throughout your studies what have you found to be areas of interest within geotechnical engineering?

Through many design projects, I developed an understanding that geotechnical engineering as one of the most significant factors in dictating the duration and cost of a project in both the design and construction stage of a project. However, what I found most interesting about geotechnical design was the design of the structure in service and how future surrounding projects may affect the geotechnical design. Impacts such as new loading or the removal of material within the zone of influence of a design are difficult to predict, but simultaneously need to be considered within the design.

 2.       What did you base your study on in order to win this award?

One of the main modules in my 4th year of study was the group design project that involved the redevelopment of Craven Cottage football stadium in Fulham. Within the project, we were each tasked to design structural elements that would meet the specific criteria set by the clients. One of the most challenging requirements was to incorporate a new underground car parking structure that would include 750 new spaces. To limit the interference with any pile foundations in the listed stand that was to remain, the cark park was situated in the same footprint as the playing surface. To remain in this footprint, five levels of parking were needed for the 750 spaces. This meant a retaining structure needed to be designed for an excavation of 21m in depth. To achieve this, I considered the use of a secant pile wall installed to a depth of 25m. The design considered to use of top-down construction to minimise the depth of excavation at any point to only be 4m (the depth of one floor) and maximise the use of the monolithic floor slabs with the secant pile wall which acted as props to resist the earth-pressures of the excavation. With the use of software and hand calculations, the maximum moment experienced in the retaining structure occurred after the top slab had been installed and the level below had been excavated. To resist the loading, the secant pile wall was 1m in diameter which would mean a vast amount of material would be required considering the perimeter of the pitch was in excess of 300m! This meant that in the final stage of the group project, we heavily discussed whether 750 spaces would actually be necessary for the cost and time it would take to build.

 3.       What are your career aspirations within geotechnical engineering?

Although it may not be the exact area I choose to specify in, geotechnical engineering will be prevalent with my civil engineering career. However, I am very conscious that in all sectors of engineering, that has to be a focus on sustainability. My 4th year dissertation examined the composting ability of compostable plastic bags. Although the compostable material reduced the solid waste associated with carrier bags, its production used a greater amount of non-renewable resources and have produced larger emissions than its single-use plastic counterpart. This showed that there are no single solutions to solve current environmental issues. I believe an area within geotechnical engineering that needs further exploration is how materials can be better re-used within a project. 

4.       How do you view LECA® LWA? Is this something which you have encountered in the past during your studies? 

I can definitely see where LECA® LWA would have been advantageous in certain designs where the bearing capacity of the construction material is low. I believe a further understanding of the benefits of lightweight aggregate may have led to a greater exploration of its use within the design projects. 

5.       What advice would you give to anybody who would like to go into geotechnical study?

In one of my first geotechnical lectures at university, my professor suggested that “geotechnics is not an exact science, but rather more of an art form”. At the time, as a class of young, inexperienced students thought it was comical to suggest that calculations involving soil could be a form of art. But when design projects became more advanced in the later years of study, where slope stability, retaining wall and foundation design became prominent, it became clearer what the lecturer was trying to indicate. Unlike the design of typical structural elements, the exact environment in which geotechnical elements are to be constructed is not always known. This coupled with the interaction of existing structures and natural features to the new geotechnical element mean that there are no specific steps in a method of calculation that will cover all elements of the same type. It is therefore critical to approach each design without any preconceived ideas that it will be exactly the same as previously similar designs. 

- We would like to congratulate George and wish him all the best in his future career within civil engineering! Well done!