Geotech#
The role of geotechnical engineering is to ensure that an acceptable state of equilibrium is achieved after constructions, at or under the ground surface. As such, the Geotech consultants work comprises of the geotechnical design of the required temporary and permanent structures (referred to as ‘underground works’) for the Advanced Building Design project.
The geotechnical engineer in this project should first ensure a safe and robust load transfer from the building to the supporting ground without compromising the global stability of the structure. In addition to the bearing capacity of the foundation system, the induced soil deformations need to be limited to avoid additional distress to the structural elements (beams, columns, and slabs). Furthermore, the building is embedded in the ground because of the multi–storey underground space, located beneath the building. In doing so, a ground model needs to be established based on the geotechnical interpretation of experimental and field soil investigation data. The geotechnical engineer will be responsible for proposing and designing feasible solutions providing:
safe excavation pit for the construction area of the building including parking area (temporary structure)
safe and robust design of the foundation system (permanent structure) and
watertight and durable basement wall (permanent structure).
Chief Consultant: Varvara Zania
This document covers the following
Skills and motivation#
Geoechnical Consultants have the following skills and motivations:
Experience with geotechnical design (desirable- at least one member)
interest to explore different materials and techniques
Analsyse existing drawings, model and building to establish current carrying capacity.
Ability to listen and grow from feedback (essential)
Willingness to explore different options
Enthusiasm to find solutions that work for the whole team.
Your chief consultant can support you with#
In the project you will be supported by the chief consutlant with the following:
Understanding the role of the Geotechnical consultant
Assessing the current carrying capactiy of the existing foundations
You will need to independently learn#
Work in BIM / Design software to develop your designs
Develop the interfaces between the disciplines in your team.
Work out the questions you need to ask in consultancy sessions.
Work out how to keep the team moving so that they are not sitting around waiting for you.
Assignments#
Part A#
Design Management Scheme#
Identify the parts of the project and the associated deadlines and collaborative requirements for the geotechnical group for the 13 and 3 week period and provide these to the PM in a timely manner to be coordinated by your PM group. In order to achieve this and define the relevant tasks, and milestones for the overall project planning you need to have prepared:
Evaluation of the available geotechnical information including:
Soil conditions,
Laboratory and field test data
Overview of foundation principles and retaining system layouts.
Overview of limit states for the design of the retaining and foundation systems according to EN 1997.
Part B#
@Varvara please check against general Part B description
B Drawings#
At this stage of the project you should have developed preliminary geotechnical design models for the underground works. These will be depicted in four drawings that contain:
Presentation of the ground model. Soil stratigraphy and soil parameters for each layer
Overview of the foundation(s) layout of superstructure, presented in plan view along with the footprint of the building and showing relevant structural components
Overview of the retaining system to support the excavation, presented in two cross sections in two orthogonal directions of the building. Include interactions with the new building and if relevant interactions with the neighbouring buildings.
Moreover the following milestones should be met that will help you to create the required drawings:
Identification of major geotechnical challenges – focus areas in the project
Overview of expected design procedures and calculation methods. Identification of design verification limit states, load cases and combinations including selection of partial factors of safety in accordance to EN 1997 -1.
Preliminary definition of design load cases in co-ordination with the Structural Engineer.
Definition of an interaction model between the superstructure and the foundation in coordination with the structural engineer.
Design Options#
Documentation of 2 Different design options.
B Client Report#
Contribute towards the client recommendations for your subject, what options would you recommend to the Client?
Part C#
C Consultant Report#
Your report should include:
Design basis (ground model, loads, load combinations, safety factors of safety, preliminary geotechnical design models)
Preliminary design for the ultimate limit states of the foundations, retaining structures (temporary) and basement wall.
Definition of the interactions at the basement area between the permanent retaining wall, and the structural components in the parking area in coordination with the structural engineer.
Construction plan incl. interface to adjacent structures and groundwater control
Drawings: Plan (1:100) and cross sections (1:100)
Plan for the final design calculations to be carried out in the 3 weeks period. This should include the final geotechnical design models.
C BIM#
Provide the team with a BIM model to support coordination with the other subjects. The BIM Model should contain the following elements:
Retaining system (sheet piles, diaphragm wall, anchors, struts, foundation system)
Part D#
D Consultant Report#
Design basis (final version). This includes final geotechnical design models in addition to the 13 week report content.
Final design including both the ultimate and the serviceability limit states (ULS and SLS) of the foundations, retaining structures (temporary) and basement wall.
Assessment of soil-structure-interaction effects in collaboration with the structural engineer. The soil foundation stiffness is first estimated for static and dynamic load conditions, thereafter the effects of compliance on the structural performance is assessed.
Plan for additional soil investigation and monitoring during construction.
D BIM#
The BIM Model must contain the following elements:
Retaining system (sheet piles, diaphragm wall, anchors, struts etc.),
foundation system (raft foundation, piles etc.)
Your BIM should be created as per your agreement with PM so they can take off the quantities they need and so can the materials consultants
Requirements#
Basement area boundary#
The basement should not extend beyond the site boundary.
Parking (ommitted 2025)#
Geotechnical structures#
Design of geotechnical structures shall comply with the basic requirements for resistance, serviceability and durability of structures. EN 1997 principles should be followed.
Geotechnical design#
The general requirement for reliability of the geotechnical design is fulfilled by the application of the principles delineated in EN 1997.
Ground model#
Processed information from ground investigation and other available data shall be collected in a Ground Model.
Geotechnical design model#
A Geotechnical Design Model shall be developed for each geotechnical design situation and associated limit states, as expected for each underground structure (foundation and excavation support systems) for ULS and SLS.
Construction concept#
The factors that influence the selection of the excavation support method and the foundation type (thereafter also the construction materials) should be carefully assessed. A concept for the foundation layout, the excavation pit, and the basement system should be developed.
Excavation support#
Define after appropriate design verifications the materials and dimensions of the support system.
Foundation type#
Define after appropriate design verifications the materials and dimensions of the foundation system.
Basement wall#
Define after appropriate design verifications the materials and dimensions of the basement wall.
Tunnels#
You can choose to include or ignore these. This a decision for your team correlated against the information that you find / look for.
Integration#
Geotech -> Architecture#
The coordination with the architect is essential in the integration of the car parking and the access roads in the construction site. Also consider for fire safety adequate evacuation strategy of the underground car parking.
Geotech -> Structures#
The collaboration with the structural engineer should be continuous throughout the duration of the design phase. The following are the focus areas:
Load transfer mechanism from the superstructure to the foundation
Identification of areas with potential of uneven load distribution
Load cases to be considered in the design of the foundations
Effect of soil deformations in the serviceability limit state to the structural behaviour
Structural elements in the basement area and interactions among them
Stiffness of the soil-foundation system and assessment of soil-structure-interaction for the static and dynamic response of the structure.
Geotech -> MEP#
The coordination with the building services is essential for adequate space allocation in the underground areas of the construction site of relevant installations.
Geotech -> PM/ICT#
Be aware of the waste management system you chose, to remove the waste from the building and coordinate the height of the basement accordingly. Is it from –1 Level, removed by a waste management truck, that results in a higher floor to floor for –1 Level than for –2 Level and –3 Level. This results in the access ramp to be either inside or outside the excavation/retaining system area, therefore, coordination of these has to be between Geotechnical Engineer, Structural Engineer, Architect, MEP, Fire and PM.
Geotech -> Materials#
The material selection for the building components in the underground space should be coordinated with the materials engineer. You should consider the different alternatives that are available and discuss the pros and cons balancing design criteria and sustainability.