Building Information Modelling (BIM) technologies are changing the conventional structural design process. BIM level-1 and level-2 are providing guidelines and frameworks for standardization with the standard Industry Foundation Classes (IFC) and collaborative design respectively. However, the predicted full potential of BIM, BIM level-3, which is a smart design system, is still in its infancy stage. Many studies focus on single technologies that BIM envelopes and do not grasp the benefit of incorporating all technologies into one model. Additionally, the industry is lagging in the adaptation of BIM technologies, since, as of today, only one company in the world is BIM level-2 certified. Witteveen+Bos recognises the potential of smart systems and is developing many innovative software solutions. In this thesis, as the objective stated, a conceptual partly BIM level-3 excavation site design tool has been developed. The developed tool, integrates parametric design with Plaxis, GIS and RockWorks. The developed tool helps stakeholders to visually explore many design solutions in a short amount of time, based on the costs, MKI, structural- and environmental requirements and the characteristics of the surroundings. The name SET (Smart Engineering Tool) was given to this tool.
Three essential boundary conditions are distinguished for the design of an excavation pit. Soil Layers, groundwater levels and the surrounding buildings. These boundary conditions impose loads and requirements on the excavation pit. The way the groundwater can be kept out determines mostly the costs. For this reason, SET works-out designs with a natural impermeable clay layer, an artificial underwater concrete floor or an artificial impermeable gel layer. Additionally, designs with different retaining walls and grout anchors or struts are worked-out. The design of an excavation pit must meet structural and environmental requirements. A vertical, horizontal and moment equilibrium must hold in the excavation pit. In urban areas, the most important concern is avoiding inadmissible damage or hindrance to adjacent structures, because the surrounding buildings are owned by third parties and deformations, causing damage to these buildings, happen quick. For this reason, the design of the excavation pit must meet the settlement requirements of the surrounding buildings. For each design, “Economisch Meest Voordelige Inschrijving” (EMVI) (Economically Most Attractive Tender) scores are used to quantify each design on durability, the impact on the surroundings, hindrance and risk. EMVI in combination with the cost estimates is used to find the design with the best cost to quality ratio. Rijkswaterstaat has determined a “Milieu Kosten Indicator” (MKI) (Environmental Cost Indicator) value for each building material. In this thesis, this value is used to quantify the environmental impact of a design
An analysis was made on the capabilities that a design tool should have. A literature study was performed on the BIM technologies. From this analysis six BIM technologies are included in the development of the tool. These are: parametric design, algorithmic design, collaborative design, central repository, interoperability and standardization. Additionally, for the development of the design tool, different programming languages and development platforms were considered. A combination of Python and JavaScript together with the Web-based Graphics Library (WebGL) was found to be most suitable. A Python back-end processes the data and runs a design algorithm, while the web-based front-end facilitates collocative design and 3D visualisations. The sever, created with the Python module Django, is used for the communication between Python and JavaScript. The JavaScript module Three.js is used to utilize the WebGL capabilities.
The development of the design tool, called SET (Smart Engineering Tool), is based on the method of rapid prototyping. This includes prototyping, test and review, refine and iterate. The prototyping process is split into four stages: (1) Interoperability and Standardization, (2) Design algorithm, (3) Collaboration, Interaction and 3D Visuals and (4) Integration. In each of these stages, an essential part of SET was developed. SET is interoperable with Plaxis 2D, a geotechnical finite element program and uses the input of GIS and RockWorks. SET’s internal design algorithm determines what excavation site designs should be calculated by Plaxis. This is based on user settings, and the boundary conditions, surrounding and environmental requirements. The boundary conditions are extracted from GIS files and from RockWorks models. The surrounding buildings are extracted from GIS, and RockWorks supplies the soil stratification. The design tool interprets these boundary conditions and standardizes the data. All data is transferred to a parallel computer, where finite element calculations are performed in Plaxis. Plaxis calculates the vertical, horizontal and moment equilibria and the deformations of the soil. SET analyses the successful Plaxis results and performs a unity check on bending moments in the retaining walls together with an analysis on the settlements requirements of the surrounding buildings. SET is tested and reviewed, by a geotechnical expert and an engineer, with two test cases. The results of these tests cases were analysed and validated. The functionalities and the user-friendliness of the tool have been scrutinized. Based on these tests, SET was reviewed, and refinements and iterations of the design tool emerged.
During the development of SET, Witteveen+Bos was working on a tender. The tendered project is a design of a bus lane next to the existing train tracks and is called “Hoogwaardig Openbaar Vervoer in het Gooi” (high quality public transport), in short “HOV in ‘t Gooi”. The currently level intersection of the bus lane with the ‘Oosterengweg’ was used to test SET with two test cases. A tunnel for the Oosterengweg underneath the train track and bus lane, was the first case and a tunnel for the train tracks and bus lane underneath the Oosterengweg, was the second case. The first case, was a similar solution as the final tender design of Witteveen+Bos. The second case however, was an “out of the box” design and which was initially deemed unfeasible by Witteveen+Bos. The testcases took around one hour to prepare in SET. For both test cases, the corresponding Plaxis calculations took around a day of computation time to finish. As a result, SET found many feasible designs for both test cases, in two days. The design of the train and bus tunnel, that was deemed unfeasible, was found to be feasible and almost a third of the cost compared to the Oosterengweg tunnel. However, it must be noted that the costs to redirect the train tracks and the maximum obstruction time of the train was not included in these designs.
It can be concluded that SET is partly BIM level-3. The foundations of the SET lie in BIM level-1 and -2. The design tool supports 2D and 3D visuals and parametric design is used in an object-oriented manner for the design of the excavation pit. The tool does not use the all-enveloping BIM standard IFC. However, the design tool does use standardization. Based on requirements from the surroundings and the environment, SET helps to explore a large number of designs in a short period of time and visualizes different designs in 3D and in an interactive graph. The data is managed from a server, which acts as a central repository. Stakeholders can access this server from a web browser and are able to analyse their preferred designs within the extended design space.
SET shows 6 major benefits. (1) During the conceptual design phase, the feasibility of designs in a large design space can be analysed without being labour intensive and within a short amount of time. (2) The decisions concerning the final design can be postponed to the very end. Thus, designs that would conventionally be deemed unfeasible in the conceptual stage can emerge as feasible in later stages. (3) The possibility of a collaborative platform stimulates shared and parallel decision making. Each stakeholder can incorporate various requirements, limitations and responsibilities into the model, which utilizes the knowledge and expertise of each stakeholder. (4) The design tool can be used from the very beginning in meetings and discussions with clients to convey information in real time, by the means of 3D visuals. Clients can be granted remote access to SET and evaluate design solutions from the comfort of their office, without sharing valuable scripts and sensitive or private data. (5) Calculations can be processed automatically on a parallel server without the supervision of an engineer. (6) SET integrates multiple design tools like GIS, RockWorks and Plaxis. Overall, SET reduces the required labour to create a design and increases the productivity of an engineer. This reduces the costs of the design process and allows engineers to create “out of the box designs”.