Sydney Architecture Images- Gone but not forgotten

State Office Block

architect

Project Architect: Ken Woolley

location

94 Phillip Street (Chifley Square) Cnr. Macquarie and Bent Streets, Sydney

date

1964-97

style

Late 20th-Century International

construction

see below 32 floors, 128 m.

type

Office Building
 
i didnt mind the SOB. it was a great deisgn. but its 800sqm floor plates was main reason why it was longer viable. way too small for modern office plates.
also it was full of asbestos.
it was worthy of being country's tallest for 2 short years.

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The State Office Block was built between 1961 and 1964 in the historic government quarter of Sydney. It was opened by the then Premier Robert Askin on 19th September 1967. For a short time it was Sydney's tallest building, and was one of the last major government buildings constructed in this quarter. The office of the Premier moved into the building from the Old Treasury Building, and State Cabinet meetings were held in the top-floor cabinet room.
The State Office Block was designed by Ken Woolley, a young architect in the NSW Government Architect's Office under the Government Architect EA Farmer, and was built by the NSW Department of Public Works.
These arms were created in oxidised bronze by sculptor Bert Flugelman. The Arms were made by Flugelman to be double-sided, as they were viewed from both sides within the lift lobby, and were the only coat of arms in the building modelled and made in this way (Woolley; State Office Block).
Image source: GPO 2 - 36139 State Library of NSW, Picman

NSW Coat of Arms, State Office Block
- The State Office building topped out in June 1965, and became the country's tallest skyscraper. It held the title until late 1967 when eclipsed by the 170m Australia Square tower. The building was dismantled over 9 months in 1997-98 to make way for the new KPF tower Chifley Tower
- Contained offices for the Premier of NSW, prominent ministers and a selection of State government departments. Level 8 contained a staffed apartment for the Premier of NSW. 
- Was demolished to make way for construction of Chifley Tower. The demolition of this building upset many Australian architects who claimed the State Office Block was a very fine example of mid-1960s modernist architecture. 
- Structural engineer Taylor Thomson and Whitting, Consulting Engineers 

- Builder Concrete Construction 
Function Commercial office building 
Year 1967 
Location Sydney, NSW 
Cost $14m including all furnishings and equipment. 



Building 
Type office building with parking for 127 cars 
Form 
- Plan shape Square in plan with central core. 
- Number of stories 38 levels, 3 basement, 1 ground floor and 30 office floors 
- Total floor area 34 728sq m 
- Net rentable floor area 23 091sq m 
- Number of modules 1 U shaped module, 1 core 
Relationship to ground ground level pedestrian entrance, underground parking 

Primary Structure 
material composite structural steel/concrete 
floor system 
- type beams, composite metal deck/concrete floor 

- pattern Rectilinear beams, one-way floor slab 

- beam clear span 10.15 m 

- floor slab span 2.8 m 
core structure 
- material reinforced concrete 
- type core 
- shape rectangular 
support structures 
- types external columns 
- material composite structural steel/concrete 
footings flat slab, footings 

Design requirements 
The State Office Block occupies one of the finest location in Sydney, forming a transition between the Botanical Gardens and The CBD area. The State Office Block is is the first major office building erected for the N.S.W Public Service since 1927 and provides accommodation for six departments - the Premiers Department, The Treasury and the departments of agriculture, local government , mines and public works. The rental office space in the tower of 796 square metres per floor and there 34 floor. The site area is 4010 square metres, and is unusual and awkward in shape. The building consists of three main parts; a central tower of thirty five floors above ground, an eight storey wing to the North (North Wing) and a nine storey wing to the East (The Premier Wing). The shape, size of site and requirements of north and south light influence the form of the building. Sun control is further provided by the reduction of window sizes to the east and the west, and the overhangs created by projecting floor slabs which are a feature of the facade. 

The concept of the tall tower block with its two wings resulted in more than half the site being given over to public space. This space is used by people entering and leaving the building, and has been landscaped to provide a setting for the building. A fountain forms part of the landscaping scheme on the corner of Macquarie street which also acts as a cooling system for the air conditioning plant. The whole ground floor of the tower is for pedestrian use. 

The tower is placed on the corner of Bent and Phillip Street. It is planned with a central lift well and service core, the plan arrangement permitting column free office spaces. This was achieved through consultation with the structural engineer resulting in an economical structural solution using a composite system. There are three levels of parking in the basement of the tower, however this parking is inadequate for the parking requirements of today. 

The structural requirements arising from the above decisions are a beam span of 10.2m and 2.8m form the composite deck for the office floor system, a floor to floor height of 4.0m and supports at ground level around 5.6m spacing. Functional modules, with dimensions varying from 5.6m to 11.2m exist at the car park levels. 

In addition, office floor slabs, levels 1-9 and 11-31 are required to carry an applied load of 3.8 kPa (partition loads .95 kPa). Levels 10, 32, and 34, are designed with a 4.8 kPa live load because of their plant room requirements. The ground floor live load was designed at 4.8 kPa with no partition requirements while the basement loads were designed to 9.6 kPa with equal partition loads. The roof load is 1.4 kPa, with an allowance to store materials. The north wing levels 1-8 were designed to a accommodate a live load of 6.2 kPa and a partition load of .96 kPa while the roof has a design capacity of .38 kPa for storage. The Premiers wing first floor was designed to take a 4.9 kPa. Levels 2-9 are designed for a live load of 3.8 kPa with partitions at .96 kPa, while the roof is the same as the north wing roof. 

The site is underlain by Hawkesbury sandstone of Triassic age, which is generally of medium to high strength apart from a few near horizontal shale with clay seams. The bearing pressure on the foundation should thus be limited to 3 MPa. 

The features of the tower block are the bronze clad columns and the protruding floor slab on every floor. Not only do they reduce solar heat gain but also act as platforms for cleaning and maintenance of the exterior. They also reduce the effect of rain cascading down the face of the sheer walls and reduce the total wind force acting on the building thus reducing structural costs. 

Structural Solutions 
The key requirements that influenced the selection of structural solutions were (a) an efficient floor system to span 10.2m, (b) floor system that minimizes the floor to floor height, (c) speed of construction to enable early tenant occupancy and (d) cost. 

Structural Alternatives and System Selection 

The following structural alternatives were considered for the floor system based on the above key options. 

composite steel/concrete 
reinforced concrete slab and beams 
The use of "Celdek" flooring for all upper floors employed the use of structural steel floor beams, this means that each section of the building forms a steel frame.Steel has a high strength to weight ratio and is thus a more efficient material for spanning 9.9m and for minimizing the structural depth required for the floor system.Fixed -ended floor beams allow the minimum floor depth to be kept to 700mm overall. The "Celdek" floor is fixed to a structural steel beam system at 2.8m centers, the beams are welded to plates set in the core and fixed against rotation in the column. Use of steel beams for the floor systems also permits the integration of structure and services, with the services zone being within the horizontal zone for the structure. Final distribution of power, internal and pmg telephones, is carried out through a sheet steel cell duct system forming part of the lightweight floor construction access to which is obtained by drilling through the concrete and fitting special floor pillar outlets. 

The composite steel/concrete construction has a number of advantages which results in reduced construction time. The steel deck for the composite construction provides a working platform during construction, and eliminates the need to either prop or strip form work and the attendant delays resulting from these operations. 

The exposed steel in the concrete construction, however, requires fire protection.The steel floor deck and beams was sprayed with vermiculite. 

The columns were constructed of a composite steel and concrete system, this was an efficient alternative to reinforced concrete as it allowed fore a smaller cross sectional area of the column, and substantial cost savings. This composite system was the first to be used in the Southern Hemisphere. 

The central concrete core, containing lifts and services, is also the major stabilising element. The choice of concrete was influenced by the smaller space required, the lack of diagonal bracing or rigid frame necessary for a steel core, the uniformity of size of all duct and lift shafts for the full height, and the over all lower cost of a concrete core. 

Final Structural Solution 

The floor system for the tower is of composite construction and consists of a rectilinear arrangement of universal steel beams, with a composite floor of " Celdek" steel sheet and concrete. 

The central rectangular core is reinforced concrete. The steel beams span from the core to the external composite columns, and are rigidly connected, as you w 

The columns on the perimeter of the building are at 2.8m spacing and of composite construction.The exterior columns are made up of four structural steel channels forming a battened column to carry the floor beams during erection. The light steel column is sufficient to carry all construction loads for ten floors above the concreted column, including the Cledek flooring. Longitudinal bars with ties encircle the reinforcement within the concrete column and are arranged to increase support at floor levels where bending stresses are greatest. 

The column spacing at ground floor is increased by a plate grider which distributes the loads to columns at 5.6m centres. 

There are four levels of basements which cover the whole site and are of all - concrete construction. The concrete slab at ground floor spans 9.6m to form the foyer areas. The reinforcement is arranged to limit the deflection to very low values. The basements are divided into two areas by a joint and bear on two large neoprene pads which allow movement between the tower and the Premiers wing. 

The footings consist of a flat slab and pad footings potted into sandstone. 

Premiers Wing: Has a conventional rigid frame fully welded for stiffness and lateral loading. Fix ended beams allow the floor thickness to be kept to 700mm in total. 

North Wing: A double cantilever portal frame at 5.5m centres was erected as complete frames and welded into position. 

The structural elements that contribute to the different functional systems are: Structural types: composite steel deck/ concrete floor , external columns and piloti , and core
material: composite steel/concrete 

Structural type: core
material - reinforced concrete 
Structural types: - raft slab and column footings
materials - reinforced concrete slab

Design Decisions 
The tower was placed on the corner of Bent and Phillip Street. It is planned with a central lift well and service core, the plan arrangement permitting column free office spaces. This was achieved through consultation with the structural engineer resulting in a n economical structural solution using a composite system.There are three levels of parking in the basement of the tower. 

The building consists of three main parts; a central tower of thirty five floors above ground, an eight storey wing to the North (North Wing) and a nine storey wing to the East (The Premier Wing). The shape, size of site and requirements of north and south light influence the form of the building. The concept of the tall tower block with it's two wings resulted in more than half the site being given over to public space. 

The features of the tower block are the bronze clad columns and the protruding floor slab on every floor. Not only do they reduce solar heat gain but also act as platforms for cleaning and maintenance of the exterior. They also reduce the effect of rain cascading down the face of the sheer walls and reduce the total wind force acting on the building thus reducing structural costs. 

References 

Architecture in Australia Feb 1968 pg 75- 87 
Interview with the consulting Engineers Mr T Wilson and Mr J Markham at Taylor Thompson and Whitting 10/9/96 and 16/10/96 and 17/10/96 
Drawings form Department of Public works and Services and Taylor Thompson and Whitting 

Thanks to http://www.arch.usyd.edu.au/kcdc/caut/html/GPT/front.htm 

 

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