Optimisation of complex geometry buildings based on wind load analysis

One result of climate change is the increasing strength and frequency of wind events. This creates a problem for the also increasing number of high-rise buildings many of which are of unconventional shape. However, current methods for calculating wind response either do not account for these geometries, such as the Eurocode or are prohibitively expensive and time-consuming, such as physical wind tunnel tests. This thesis aims to address this issue by developing a computational method by which one can analyse the structural effects of wind on a building and optimise the external geometry to reduce those effects in the early design phase. The method involves the combination of three main algorithms: Computational Fluid Dynamics (CFD) to simulate the wind and the pressure it exerts on a building, Finite Element Analysis (FEA) which calculates the structural effects such as deflection and stresses due to these forces, and an optimisation algorithm which can iteratively manipulate an input geometry to obtain better performance. For this thesis, a tool based on the method was developed in Grasshopper, the visual scripting plugin for Rhinoceros3D. Existing plugins were used for the main algorithms while custom scripting was used to combine them into a single tool that was made relatively easy to use and returned quick results.The methodology involved extensive research into the various aspects of the method. This was followed by the development of the method throughout which testing and validation were performed to determine its accuracy and timeliness. Case study buildings were tested with the goal of reducing structural material use. In all tests, the mass of structural material needed was reduced by allowing the optimisation algorithm to manipulate only the external geometry of the building. This produced a tool within Grasshopper and a set of guidelines for developing such a method.Architecture, Urbanism and Building Science

Optimisation of Complex Geometry High-Rise Buildings based on Wind Load Analysis

Wind analysis for the structure of buildings is a challenging process. The increasing strength and frequency of wind events due to climate change only add higher demands. In addition, high-rise buildings are growing in number and include many of unconventional shape. Current methods used in practice for calculating structural wind response either do not account for these geometries, such as the Eurocode or are prohibitively time-consuming and expensive, such as physical wind tunnel tests and complex Computational Fluid Dynamics simulations. As such, wind loads are usually only considered towards the end of design. This paper presents the development of a computational method to analyse the effect of wind on the structural behaviour of a 3D building model and optimise the external geometry to reduce those effects at an early design phase. It combines Computational Fluid Dynamics (CFD), Finite Element Analysis (FEA), and an Optimisation algorithm. This allows it to be used in an early design stage for performance-based design exploration in complement to the more traditional late-stage methods outlined above. The method was implemented into a rapid and easy to use computational tool by combining existing plugins in Grasshopper into a single script that can be used in practice on complex shaped parametric high-rise building models. After developing the method and testing the timeliness and precision of the CFD, and FEA portions on case study buildings, the tool was able to output an optimal geometry as well as a database of improved geometric options with their corresponding performance for the wind loading allowingfor performance-based decision-making in the early design phase.Design InformaticsStructural Design & Mechanic

Optimization of complex-geometry high-rise buildings based on wind load analysis

As technology advances, architects often employ innovative, non-standard shapes in their designs for the fast-growing number of high-rise buildings. Conversely, climate change is bringing about an increasing number of dangerous wind events causing damage to buildings and their surroundings. These factors further complicate the already difficult field of structural wind analysis. Current methods for calculating structural wind response, such as the Eurocode, do not provide methods for unconventional building shapes or, in the case of physical wind tunnel test and in-depth computational fluid dynamics (CFD) simulation, they are prohibitively expensive and time-consuming. Thus, wind load analysis is often relegated to late in the design process. This paper presents the development of a computational method to analyze the effect of wind on the structural behavior of a 3D building model and optimize the external geometry to reduce those effects at an early design phase. It combines CFD, finite-element analysis (FEA), and an optimization algorithm in the popular parametric design tool, Grasshopper. This allows it to be used in an early design stage for performance-based design exploration in complement to the more traditional late-stage methods outlined above. After developing the method and testing the timeliness and precision of the CFD, and FEA portions on case study buildings, the tool was able to output an optimal geometry as well as a database of improved geometric options with their corresponding performance for the wind loading.Design InformaticsStructural Design & Mechanic