1. Introduction

Rapid increase in high economic growth and employment opportunities in Bangkok have led to an influx of labour immigration resulting in a surge of suburbanization around the metropolitan. This expansion of the city have resulted in the elimination of existing vital agricultural land, forest and water basins surrounding the area (Tonmanee & Kuneepong, 2004, p. 117). The lack of city planning, in term of growth, have led to an ecological imbalance causing many problems such as the dissolution of agricultural settlements from urban sprawl, congestion in the core of the city, irrational and ever growing commuting distances which aligns with the view of Doxiadis’s Ekistics thoery (Doxiadis, 2005).

This paper proposes that a transportation system developed based on several city growth theories such as Doxiadis’ Ekistics theory, Metabolism movement and Batty’s Fractal Cities could potentially solve some of these issues. By using these three main theories (Ekistics, Metabolism and Fractal Cities) to understand the urban sprawl by the translating them into biomorphic growth, we can attempt to control the direction of growth through physical infrastructure arrangements, topology and geometry of street and rail systems (Michael Batty, 2008, p. 770).

The paper will utilise urban parametric design strategies such as biomorphic growth simulations through the Processing language, shape grammar and deep relationality (Schumacher, 2009, p. 17) in order find alternative design methods towards the solution.

The site, located in southern Lopburi of Thailand, was chosen based on the continual growth of Bangkok and the decrease of agricultural land (Tonmanee & Kuneepong, 2004, p. 116) and the government’s urban planning for the near future, the proposed site have a high potential to transform into an unbalanced urbanization between urban sprawl and agricultural settlements. The program of a transportation infrastructure would influence the directional growth of the city’s network system (Doxiadis, 2005, p. 52).

2. Problem statement

Constantino Doxiadis believes that cities are becoming more dynamic and a new framework for a city that are constantly expanding is needed for better urban design. (Doxiadis, 1963) This paper questions: how can infrastructural of transportation systems influence and possibly improve the urban design of expanding cities through biomorphic growth models?

3. Methods

The paper commences with relevant literature reviews on city growths, focusing on the Ekistics theory (Doxiadis, 1963), metabolism movement (Kuan, Lippit, & Harvard University. Graduate School of, 2012) and fractal cities (M. Batty & Longley, 1994). Critical site analysis are carried out to provide contextual input during the experimentation process. Development of parametric urban patterns and growth of the optimize transportation network are then generated through the systems generation process, the structure is adapted from Kolb Learning Cycle (Kolb, 2015).

The experimentation on relevant case studies allows the generation of a design framework. The first type of case studies will be based on the simulation of growth using the computer language Processing. This stage explores the mimicry of growth from high parameter inputs (low levels of self-generations) to fully self-generated growth based on biomorphic algorithms (Lange, 2012).

The second type of case studies revolves around Shape Grammar, testing of geometrical growth in both 2 Dimensions and 3 Dimensions to assist in architectural and urban environments (O'Neill et al., 2009). Geometrical growth models such as the Padovan Sequence, Golden Ratio, Laplacian Circle Packing and Fractal Growth are explored and applied to the local context. Existing work on Shape Grammars on hierarchical transport network design (Vitins, Schüssler, & Axhausen, 2011) and Urban Grammars (Beirão, Duarte, & Stouffs, 2011) are also analysed in this stage.

The third stage consists of experimenting with different network connection systems using Grasshopper and Rhinoceros. Systems such as minimal path system, attraction occupation, direct path systems and other relevant systems are tested out.

After the observation, the contextual data are implemented for an active experimentation in each of the case studies. The evaluation process concludes whether the system solves issues formulated.

The cycle is repeated until a satisfactory outcome is produced, thus leading to a framework of selected methods that is deemed most effective for the generation of urban growth for a transportation network system.

The framework is then carried out on the local context focusing on three different levels: pedestrians, automotive and railways, the network systems generated from previous experiments will shape the design outcome which will assist in an informed developed design.

Reflection of the effectiveness on the parametric explorations will be carried out to determine whether the usage of biomorphic growth models can assist in designing an efficient transportation system.

4. Results

It is expected that the experiments of this paper will give a deeper understanding if and how biomorphic growth studies can be utilise for assisting in designing a transport system that anticipates the growth of cities. The case studies will help determined whether certain parametric systems are more effective than others when applied with the formulated urban problems, thus leading to a framework that could assist the design stage by treating cities as an ecological organization. The result of the framework will generate a design proposal for a transport network and system infrastructure with the aid of biomorphic generation.

5. Discussion

This paper have the potential to contribute to the study for transportation network system in a rapidly expanding environment which are currently under-researched (Vitins et al., 2011), which can influence future urban designs in many areas around the world. The framework can be adapted for different urban problems which could lead to new findings that will allows for more effective parametric assisted design methods. The results of the experiments of case studies can contribute to the generative design community as a guideline of existing technologies and potential usage that is time-saving and informative.