20 October 2015
The Geelong Library and Heritage Centre (GLHC) is a state of the art, $45.5 Million construction set for completion in November of this year. Designed for the Geelong City Council, the striking new building replaces the old library built on the same footprint and will become home to Victoria’s largest regional collection of public and private records.
With architectural design from ARM Architecture and structural and civil engineering from Irwinconsult, GLHC was recently awarded the 2015 Victorian Excellence in Concrete Award by the Concrete Institute of Australia for its innovative use of concrete and glass reinforced concrete.
The GLHC facade has a unique dome like form. Derived from a sphere with a diameter larger than the site, the sphere is truncated on the east, south and west to fit within the title boundary. The northern portion of the façade, known as the ‘Shield’, is separated from the main facade creating the Level 5 outdoor terrace with scenic views of Corio Bay and Johnstone Park. A large rectangular opening penetrates the top of the facade providing natural ventilation to one of the two plant floors.
Unlike conventional domes – which transfer loads to foundation via arching – the GLHC façade has a highly irregular and discontinuous load path which required an inventive steel framework for support.
The main facade framework is a layered system of curvilinear CHS tubes and pre-set longitudinal and transverse universal beams supported by a central welded column. To facilitate the column-free space in the Level 5 Function Room, at opposing ends, the framework clear spans to 25m long, welded transfer beams on the north and west and to a post tensioned concrete transfer on the south. On the east, the façade frame connects to the external feature wall. Composite columns at the underside of the transfer beams cantilever above Level 5, stabilising the façade laterally. The shear forces generated in the columns from lateral load are transferred to the core and adjacent columns via the PT floor diaphragm. The Shield is ‘stick built’ with a system of curvilinear tube mullions, stubs and cast-plates.
The GLHC façade skin is a bespoke assemblage of prefabricated glass reinforced concrete (GRC) panels. There are 332 geodesic dome panels and 190 fascia and soffit panels. The dome panels are asymmetrical and geometrically pentagonal or hexagonal with maximum widths of 2.5m and 3.5m respectively.
The lightweight, waterproof design of the panels was developed in consultation with ARM Architecture and Asurco. The panels were manufactured and transported out of South Australia by Asurco.
The panels come in 1 of 4 colours and each individual dome panel comprises a thin, convex GRC shell (ranging in depth from 12mm to 75mm) and a lightweight steel backing frame. The perimeter of the panel joint is waterproofed insitu by a multi-layer weather seal system.
Weighing in at around 300kg, each panel was lifted into the final position by mobile crane and bolted directly to the primary and secondary façade framework by a single, central stub connection. The central stub connection is adjustable in all directions which allowed for precise levelling.
The glazing has a cavernous, crystalline appearance. To maximise floor space, the PT floors follow the same profile with extents and edges that move and zig-zag. The glazing system was developed by ARM Architecture to discreetly integrate complex thermal and service movements within the façade joint rhythm. Irwinconsult, with input from BG & E, developed the method for laterally restraining the glazing against wind at each floor level and dead loading the spandrel beams of Level 1, 2 and 4 on the west and at Level 1 and 3 on the south.
The glazing profile steps outwards and towards the west as the building gets higher, and to avoid additional columns or deepening of the band beams, the top 3 floors hang from the west transfer beam by a series of concentrically located Macalloy Bar System hanging rods. During construction, the western edge of the floor at Level 3, 4 and 5 remained fully propped to ground until the roof frame and rods were installed.
To achieve 4m cantilevers and the 9.5 x 9m column grid, floors are a one-way banded PT arrangement. As with all insitu and precast concrete on the project, a 30% cement replacement with flyash was used in the interests of sustainable design.
As many areas of the floor soffit are visually exposed, straight line beam edges were architecturally manipulated and moulded for aesthetics. Above the PT slab, the hydronic floor heating system is incorporated into a high quality, coloured floor topping with a burnished finish.
Floors are supported on insitu concrete and steel columns. Raking columns were employed throughout the building to support the dome perimeter and feature stairs and create an open lobby entry. Most columns rake in 2 directions at angles between 10 and 45 degrees. Designated PT and reinforcing steel was added to the floors to control the horizontal components of the column axial load.
The east feature wall is the primary stability wall of the building under a north-south lateral load. It also plays an important role in carrying the fire stair which winds from Basement Level 1 to 5 on a steep incline.
The majority of the wall is built from carefully articulated, precast concrete with louvered openings for further plant ventilation at Level 6. The north east corner of the wall is constructed from RC concrete below the parapet line of the adjacent Art Gallery where the internal wall of the fire stair transfers over the loading dock.
The major architectural feature of the wall is the dynamic pattern developed by ARM Architecture. The pattern mimics the glazing form and is achieved using a Reid GC Art and Design Graphic Paper with a special concrete mix containing black granite aggregates.
Placed in the precast casting beds prior to pouring, the Graphic Paper is treated with three strengths of retarding compound that variably delays the set drying time of the concrete surface. The panels are then removed from the form and high pressure hosed exposing the aggregate and creating the contrast.
Irwinconsult began schematic design of the Geelong Library and Heritage Centre in 2011, and in 2015, we are proud to have delivered all structural and civil engineering for the project. Special thanks to Geelong City Council and ARM Architecture for the opportunity to work on this landmark project.
> Client: Geelong City Council
> Architect: ARM Architecture
> Builder: Kane Constructions
> GRC: Asurco Contracting
> Concrete: Hall Concrete Constructions
> Precast: Otway Precast
> Steelwork: Geelong Fabrications