Zurich Children’s Hospital
Acute-care hospital and LLF
Zurich, Switzerland
Competition 1st prize 2011-2012
Project since 2014
Projected construction 2018-2022
Children's
Hospital.
Overview
Zurich Children’s Hospital
Client
Zurich Children’s Hospital – Eleonorenstiftung, Zurich, Switzerland
Architecture and Overall Direction
ARGE KISPI
Herzog & de Meuron, Architecture
Gruner AG, Overall Direction
Zurich Children's Hospital has been suffering from very cramped conditions for years. In order to ensure that children and youths can continue to be cared for in the future, the Eleonore Foundation is constructing a new building in Lengg, Zurich. In its entirety, the site comprises two parcels: the new acute-care hospital is being built on the south plot, while the laboratory, teaching and research building (LLF) is being built on the north plot.
With a floor area of 77,300 m², the acute-care hospital will cover the full spectrum of specialist fields in child and adolescent medicine, as well as in paediatric surgery. The new building is horizontally layered. Each floor is shaped by its respective functions: examination and treatment, emergency and intensive care on the ground floor; flexible offices surrounding a central examination and treatment area on the 1st floor; patient rooms on the 2nd floor; a car park, delivery zone and building services equipment on the basement floor.
LLF is a compact stand-alone building with a floor area of 16,700 m², in which rooms for university teaching and research, as well as clinical diagnostics laboratories, are stacked on top of each other: lecture halls, seminar rooms, a study centre and laboratories. A lecture hall and two seminar rooms, which movable partition walls enable to be joined together as one large room for up to 1,200 people, are to be found beneath the cylindrical building. Open-plan student work areas, a media centre and classrooms are situated above this room and connected with it by a large round opening. On the five upper floors, laboratories and offices are arranged along the facade in closed rooms, while open-plan work areas for doctoral students and laboratory staff surround the central atrium.
The acute-care hospital's support structure consists of a concrete skeleton with flat slabs, resting on columns and load-bearing walls in the core areas (stairwells, lift shafts etc.). Horizontal reinforcement of the upper floors is provided by means of in-situ-concrete cores installed on the basement floors. The roof is dimensioned like a floor slab and can thus be used for the helipad, for building services equipment and for extensive vegetation. The support structure is designed so that temporary containers or installations can be positioned on the roof in between the vegetation. The relatively extensive ceiling overhangs by the round courtyards are made possible by the use of pre-stressed downstand beams. The patient rooms are realised as (lightweight) wooden structures with a high degree of prefabrication (element-based design) and mounted on the floor slab. This makes it possible to arrange the patient rooms according to their spatial and functional requirements, without any dependency on the column grid beneath.
The continuous spun-concrete columns stand in an 8.40 m grid. For individual column-free areas (delivery zone) or for optimisation of column positioning in the MRI rooms, columns are braced with concrete-encased steel-concrete-composite beams that have span widths of up to 16.80 m. The highly stressed beams are supported by steel columns.
The foundation slab is installed in the good load-bearing ground as a shallow foundation with local recesses. On the layers with lower load-bearing capacity, the building rests on the molasse with the aid of bored piles, which also serve as local buoyancy protection.
Large sections of the exposed-concrete facade are seamless. The lower section of the facade (1st basement floor and ground floor) is fixed to the foundation and consists of columns, shear walls and braces, onto which the slab above the ground floor also transfers some of its load. The upper section of the facade (1st upper floor) includes the two balcony areas, which are interconnected by an exterior support and rest on the facade elements beneath. The absence of secondary bending, which this design entails, makes it possible to create unusually large seamless sections.
The LLF building's support structure consists of a reinforced-concrete skeleton with flat slabs, resting on columns and load-bearing walls in the core areas (lift and building-services shafts). Round prefabricated columns of spun concrete with a diameter of 35 cm (40 cm on the basement floor) are envisaged in the interior. Steel columns are planned for the facade layer (S355 rolled-steel sections). The seamless balconies, made of reinforced concrete, rest on rigid projecting steel beams that join onto the facade columns. In order to minimise secondary bending of the balcony, plain bearings are positioned between the steel beams and the balcony slab.
In order to make the representative lecture halls on the ground floor free of columns, local solid steel-concrete-composite beams are envisaged, to support the column loads from the upper floors. Horizontal reinforcement of the building is provided by the two reinforced-concrete cores of the lift and building-services shafts, which have wall thicknesses of 35 cm and are installed on the two basement floors.
As the ground is susceptible to subsidence and only has moderate load-bearing capacity, the LLF building has a foundation of bored piles. Although the building does not sit in groundwater, it is possible that seepage water and slope water accumulate at times. In order to hinder the building's buoyant force, the bored piles also act as tension piles. Due to the high water pressure, the foundation slabs are realised with thicknesses of 80 cm on the 2nd basement floor and 60 cm on the 1st basement floor.
Between the two plots, a delivery and disposal tunnel beneath Lenggstrasse is planned. Built using in-situ concrete, this structure with a shallow foundation is monolithically connected to the buildings at both ends, so as to eliminate differential subsidence in the transition zones.