W07 logbook

W07 – STUDIO REPORT

153 FRANKLIN ST The plan is to build 830 apartments, with a prediction of 2000 residents. The first 330 apartments are planned to be handed over in December this year.

Large prefabricated concrete columns span 2 floors each. Each column is lowered onto rebars (re-enforcement bars). These have been placed over grout which then prevents the column from moving.

On site there are generally 450 workers from Monday to Friday, 300 on Saturday and the project is currently also being worked on Sundays as well.

BASIC STRUCTURE Each floor is based on a concrete slab cast in situ. For each floor the slab is divided into 2 sections poured separately, one day apart. The slab is also pre-tensioned with wires. This, as we have learnt in our lectures, helps to balance the concretes strength under both compressive and tensile forces.

Above: The exposed steel cables used to pretension the concrete.

UPPER FLOORS Many of the upper floors have rectangular indentations. These are shower wells for the apartments.

The concrete for the upper floors is transported directly from the ground floor up a large concrete pump.

The system for keeping the formwork is a jump form system. This is comprised of a series of working platforms that are able to be detached, elevated and reattached essentially ‘jumping’ up levels. This is an ideal type of formwork for high-rise buildings as it allows for quick movement upwards. The ‘jumps’ take generally 4-6 days.

For each floor the surveyors come and mark a level, this is a set height which is marked on various members across the floor for an accurate and level construction.

It is necessary to use structural screens as a form of scaffolding in the upper floors, this greatly reduces the possibility of debris falling and causing damage on the street below.

9th FLOOR The 9th floor acts as a podium floor. From here the structure divides into two towers. The 9th floor will also play the role of a communal activities area for the residents of the apartments. It houses a spa, sauna, pool, theatre, gym, outdoor terrace, dining area and kitchen.

Above: This is the early stages of the pool.

Concrete cast in situ.

This roof had a structural steel frame, as the floor has wet areas (spa, pool and sauna) there is a need for the steel in this area of the building to be galvanised.

Cross bracing was also used in various sections.

Above: Steel bracing appeared sparsely. It occurred at each end of the pool room but the engineers decided to not have it run anywhere else. Tensioners can be seen.

Many of the smaller steel columns have been covered in a material known as promat. This greatly reduces the fire rating.

Above: Column covered in promat sheets.

As a result of small strategies such as this the building has a 4 star Green Star rating.

GROUND FLOOR

ISSUES WITH CONSTRUCTION

Whilst the ground floor does somewhat act as the building’s lobby, it will also be a public thoroughfare, in addition to this there will be retail section with up to 11 shops.

The main issues with construction have concerned the building’s façade. It is a curtain wall façade which implies that there are glass and precast panels attached to brackets extending from the walls of the building.

The ground floor has a number of very large, round columns. These are coated with a steel mould which indicates (along with their enormous mass) that they must have been cast in situ. The reason for them being circular is most likely for aesthetic purposes.

The ground floor was originally planned to be a steel stud frame system but due to the desire to improve fire ratings additional concrete block walls have been added. These also have a beneficial effect on the buildings acoustics.

Noggins Steel studs

Concrete block wall

Above: Steel stud frame supported by a concrete block wall. It is likely that the wall also has internal reinforcements.

Their supplier was taking far too long to deliver the materials and as a result the façade began to fall behind on schedule.

This is hugely important as in construction each day over the agreed completion deadline results in a $60,000 refund to the client.

The construction team then novated the company’s contracted and is now working direct with their suppliers.