水簾洞(OSAKA EXPO2025 休憩所プロポーザル案)

site plan

Rest room in the waterfall(OSAKA EXPO2025 Rest room proposal Competition)

Location: Yumeshima,Konohana-ku,Osaka Japan

Principal use:Rest room

Client:Osaka city


Gross Floor Area:830sq.m.

This is a proposal for a rest area in the Osaka Expo to be held in 2025. Our intention with this project was to design an unprecedented from and spatiality that would invite people inside,but that it would be also an architecture befitting of a festive event on the scale of the Expo,an international and celebratory occasion.

 The exterior is entirely made of water, the roof and beams are made of steel sheets like those found on any construction sites, and the pillars and foundation are made of steel ,with the aim of creating a completely different world while using materials that can be found anywhere. To guarantee its feasibility and detailing the structure was designed in collaboration with Yasuhiro Kanada, a structural engineer active in Japan and abroad.

A”Water Curtain Cave”

Based on the unique site characteristics adjacent to the Water World, and to contextualize it,we proposed a stacked rest area which allows water to move creating waterfalls to gather and spread out around it.

Creating an architecture that can only be realised at the Osaka Expo.

Given that the Expo will start in the middle of the season,from April to October, and close in the middle of the year after the middle of summer, we proposed an open rest space without an exterior area ,which is normally difficult to realize.This area consists of  a’waterfall curtain’ that uses 90% circulating water from which the remaining 10% is drinkable. It is a space where visitors can spend time in natural coolness using evaporative heat.Basically,creating a cicle reusing the circulating water, making it a realistic proposal with low running costs.

From reminiscent of terraced rice paddies,an original Japanese landscape

The stacked plattforms are reminiscent of terraced rice paddies,which are a part of Japan’s original landscape.It was designed this way with the intent of remind people of the beauty of the original Japanese landscape.

A generous space that is ‘diverse yet united’ in its stacked form.

The waterfall naturally overflows from the top of the building and flows into the lower areas.By planning various landscape,such as a place where the waterfall flows quietly,a place where the waterfalls gathers to create a dynamic landscape like a waterfall basin,a place where the surface of the water can be seen swaying from the ceiling,and a place surrounded by the waterfall,a cosy resting place is created where visitors can reset themselves from the bustling world of the Expo.This design allows the visitors  to spend time in a multitude of different places within the project,choosing the ones they prefer.

Creating a relaxing enivironment with a 1/f fluctuation effect 

Fluctuations exist in nature,and 1/f fluctuation,a moderate combination of regularity and abruptness, predictability and deviation, is said to give a sence of cosiness and calm.By controlling the flow of water in a waterfall and deliberately creating various streams,the sound of the waterfall’s flow can be differentiated to generate 1/f fluctuations.The space is planned to be comfortable for the people surrounded by it.

Shapes that allow water to flow rationally.

Fluid simulation results showed that a regular circle is the most efficient way for water to flow downwards naturally.The smaller the diameter of the root at the top,the less the pumping load on the water pump,so the roof at the top has the smallest diameter,and the building shape is designed in such a way that the diameter increases in turn,leading to a form that allows water to circulate without difficulty.

3Rs proposals

The roof is made of steel sheets,which will be cut off  at the end of the exhibition and reused at another construction site.

Excavated soil from the foundations is recycled and reused as soil pavement creating the floor finish for the rest area,and the base of the benches is also made though the same process,recycled soil wall finishy.

The ground beams are piled vertically,so that they can be easily reused as pile retaining material after the exhibition is over.

By carefully selecting materials that can be reused,such as paving iron plates, the projects was designed to reduce construction work,reduce costs and reduce waste.