Project Title:
A Portable Casting Machine – in-between in-situ & prefab casting
Author:
LAI Ho Fung
Advisor:
KUO Jze Yi
Site:
Kowloon City, HK
Category:
Construction Technique
School:
The University of Hong Kong
Academic Year:
Semester 2, 2022-2023
A thesis submitted to the Department of Architecture, HKU in partial fulfillment of the requirements for the degree of Master of Architecture.
Project Description:
Reviewing the places in the urban cities where we are living, almost all the construction are done by the professionals. This kind of top-down planning and controlled practice make our living environment becomes standard, fixed, identical and monotonous. Citizens who are the one to use the spaces and probably spend the rest of their whole life with the buildings, do not involve in the construction process and nearly have no say about their living environment.
Especially in Hong Kong, there are no culture of DIY and the spaces are limited. Based on such situation, the thesis aims to invent a new construction technique, by re-thinking the way that how concrete is being cast, to popularize the construction industry to the general.
Therefore, the invented construction technique has to:
(i) build small scale and light in weight, &
(ii) be low-tech and simple in the process,
so that it is easy for human to operate and handle, even though you are not trained in the construction professional industry.
In the construction industry nowadays, people are mainly adopting two concrete casting techniques i.e. in-situ casting and prefab casting, to construct buildings in the urban countries. Both of the existing techniques have their pros & cons. The two techniques are complementary to each other.
In-situ Casting
In-situ is flexible and handy, the technique allows the wooden formwork to be tailor-made for any shape required but the wooden formwork is one-off and a huge amount of plywood is being consumed in the building industry which makes the in-situ technique not economic and sustainable at all.
Prefab Casting
By contrast, more and more people are adopting prefab casting in the building industry with the development of building technology to increase the efficiency in construction. Molds are standardized and reused in the factory to mass-produce concrete elements for on-site assembling. Undoubtedly, prefab technique is much more economic and sustainable, however, it reduces the flexibility, the diversity and the plasticity of concrete casting.
Concrete is a material of paste-state before curing, it can be molded into any freeform and it is homogenous. Once the molds are standardized and fixed, the concrete casting will lose its flexibility, diversity and plasticity. Moreover, prefab usually relies on heavy machines in factory and on-site which makes the technique cannot be small-scaled, popularized and operated easily by human.
By studying and reviewing the existing two main concrete casting techniques in the construction industry, the thesis project extracts and combines their advantages to invent a unified new concrete casting technique for the construction industry. The new concrete casting technique is flexible, handy, yet economic and sustainable. This can be achieved through mold designs and the operations of the designed mold.
The Proposal
By rethinking and restructuring the way of concrete casting, the thesis invents several prototypes of adjustable and reusable mold to propose a new concrete casting technique. During the construction, the mold will always be adjusted by screwing the components of the mold to jamb with the concrete it cast previously for supporting and keeps the casting to go further. The mold goes along with the cast, as a casting machine allowing the concrete to grow in forming a building structure.
The proposed new way of concrete casting is economical in terms of (i) formwork, (ii) labour, (iii) construction space, and (iv) concrete material. It allows just a small group of 3-5 people in a small place, using a single mold repeatedly to cast the thinnest structural concrete.
In the operation, each worker with a casting machine on his hands, starts casting from the ground up. They begin to turn and climb up as they want and they need. The cast is ergonomic around their bodies and they can make decisions on the way they go. This new way of casting technique tolerates people to make wrong decisions and allows people to change their ideas during the construction. Therefore, the architecture made out of this new technique is so human-driven by using this sort of portable casting machine. These surprised and unintended spaces cannot be done by neither in-situ casting nor prefab casting as the existing two casting techniques require planning in advance. Moreover, the casting machine is so low-tech and easy to operate. All the technique is about how to mix concrete and screwing the components of the mold. The economical qualities of the technique facilitate the concrete casting operation and popularize the construction industry.
