Tropical Fruit Warehouse

An extraordinary redevelopment by IPUT Real Estate Dublin, the Tropical Fruit Warehouse stands in the shadow of Santiago Calatrava’s iconic Samuel Beckett bridge in the centre of Dublin. Two historic warehouse buildings, previously used for the import of tropical fruit and latterly as a studio by U2, are being carefully restored and topped off with a spectacular glass box.

In this extraordinary design by Henry J Lyons Architects, the warehouses, which feature intricate masonry and stonework, melt together with the transparent glass box, that floats above it like a light, contemporary jewel.

(Pictures: courtesy of IPUT Real Estate Dublin)

Process
At an early stage of the design process Octatube was brought on board to develop the glass box, in close cooperation with the design team consisting of Henry J Lyons and ARUP amongst others. We started with a pre-engineering period of 10 weeks. During this phase various options were proposed, and the design was assessed, both aesthetically and structurally. During a series of design workshops, the challenges were discussed, and decisions made.

For example, during this phase it was decided to put in place the second skin facade at full height (approx. 8,5 meters) instead of dividing it in two. This yielded a significant advantage for the structural scheme of the facade and increased the transparency of the entire design.

The pre-engineering process led to a clear design direction and assignment for the further engineering and execution of the project.

Double skin facade
The floating glass box cantilevers over the existing warehouse buildings. A primary concrete load-bearing structure protrudes from the warehouses, to which the steel structure is attached. The double skin facade, in which the glass spans from floor to floor, is attached to this construction.

The outer layer of the double skin facade is separated by a glass fin construction, consisting of CNC cut glass fins, and supported on the bottom by a high-quality stainless-steel construction. The fins finish 1.70 meters above the third floor (the ‘ground floor’ of the glass box), thus the facade glass protrudes beyond the fins. Consequently, you can walk under the fins providing access for maintenance in the cavity.

A unique feature of this construction is the suspension of fins from the roof, while the façade glass stands on the lower floor. This is quite a special feature. Consider what happens if one floor deforms differently than another (for example, if there are more people standing on it)? In theory, the outer layer of glass can move in relation to the fin. This is certainly challenging from a structural point of view and drove the significant time investment into detailing.

Glass corner
Extensive and detailed structural optimisations meant it has been possible to create fully glazed corners in the facade of the Tropical Fruit Warehouse. The facade glass supports itself (by means of a structural sealant) and this the glass box keeps itself in balance. These corners also reinforce the transparency of the design.

Mock-Up
Due to the complexity of this project, we deviated from standard systems. We engineered bespoke alterations in such a way that they are aesthetically attractive, but without compromising any structural quality. Due to these adjustments, the systems no longer fit into what would be considered standard certification.

That is why we created our largest ever mock-up – at 8x5 metres – one that also functioned as a test set-up in which various facade details came together. This ensured compliance with the English CWCT guideline in particular.

The mock-up allowed us to prove consistent quality and ensured that the structure met all performance requirements: giving confidence to the customer and client.

Following the mock-up, we continued to optimise the design though these were mostly small, aesthetic changes (i.e., colours or sheet metal).

The mock-up also provided valuable information and insights for the assembly: it allowed us to assess critical points that may have played a role in the assembly and need extra attention at a later stage.

Assembly
The assembly of the glass box was a challenge. Everything is done at height, suspended over the historic warehouses. A mast climbing platform was built over the entire project, guaranteeing a good work floor throughout the assembly process – both internally and externally.

We opted for pre-assembly in as much as possible. In addition to the fact that this is an efficient way of working, we can also guarantee the quality of the facade by preparing it in a controlled environment. When you consider the climate in Dublin - and the time of year – this offered a significant advantage.

Tropical Fruit Warehouse is a truly iconic building on the quay of River Liffey. The project is a wonderful example of renewal in the broadest sense of the word: the existing warehouses is restored to their former glory and at the same time enriched with a modern, glass crown.