Feature-Based Costing Method for Skeletal Steel Structures based on the Process Approach
Haapio, Jaakko (2012)
Tampere University of Technology
2012
Rakennetun ympäristön tiedekunta - Faculty of Built Environment
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-15-2795-1
https://urn.fi/URN:ISBN:978-952-15-2795-1
Tiivistelmä
This thesis presents a new method for costing the skeletal steel structures used in industrial, commercial or office buildings or constructions. Furthermore it proposes a design concept that takes the joint details into account in dimensioning assemblies. Thereby the designer can compare the costs of not only members but also joints and choose a suitable construction both structurally and economically.
The fabrication processes required to complete the assembly in a workshop as well as the processes involved in transporting it to the site and erecting it are presented. The majority of fabrication processes are assumed to be carried out using NC equipments, each executing one process in its own cost centre in the workshop. A feature-based costing method consisting of the functions developed for individual processes is created. For erection a complete new approach is presented. The cost functions have components for material, labour, equipment investment and maintenance, real estate investment and maintenance, consumables and energy. Cost functions include both pre-set values for parameters of the process environment, based on literature and observations, and variables originating from features. Variables are defined by the designer during the structural design process.
In this context the word ‘feature’ is used to refer to attributes which affect the costs of the assembly during the manufacturing, transportation or erection processes. For example, paint thickness is a feature, but the colour of a paint is a feature only if there are differences between the costs of different colours.
The reliability of the method is proved by calculating the costs of eight assemblies of varying features. The results produced by the proposed method are compared with offers received from five European workshops and results produced by a method developed in Australia and using a similar approach.
The practicality of the method is illustrated by two examples where the rotational stiffness of joints was varied.
The final conclusion is that the proposed method provides a reliable and practical tool for the designer to evaluate her/his structural decisions from the economic viewpoint already at an early design stage, as well as allows optimising a structure aimed to minimise the total cost.
The fabrication processes required to complete the assembly in a workshop as well as the processes involved in transporting it to the site and erecting it are presented. The majority of fabrication processes are assumed to be carried out using NC equipments, each executing one process in its own cost centre in the workshop. A feature-based costing method consisting of the functions developed for individual processes is created. For erection a complete new approach is presented. The cost functions have components for material, labour, equipment investment and maintenance, real estate investment and maintenance, consumables and energy. Cost functions include both pre-set values for parameters of the process environment, based on literature and observations, and variables originating from features. Variables are defined by the designer during the structural design process.
In this context the word ‘feature’ is used to refer to attributes which affect the costs of the assembly during the manufacturing, transportation or erection processes. For example, paint thickness is a feature, but the colour of a paint is a feature only if there are differences between the costs of different colours.
The reliability of the method is proved by calculating the costs of eight assemblies of varying features. The results produced by the proposed method are compared with offers received from five European workshops and results produced by a method developed in Australia and using a similar approach.
The practicality of the method is illustrated by two examples where the rotational stiffness of joints was varied.
The final conclusion is that the proposed method provides a reliable and practical tool for the designer to evaluate her/his structural decisions from the economic viewpoint already at an early design stage, as well as allows optimising a structure aimed to minimise the total cost.
Kokoelmat
- Väitöskirjat [4672]