Timber is the new Steel

http://www.infolink.com.au/articles/08/0C02F808.aspx
This article starts on a humorous note saying how the retired are not only demanding to be comfortable but now also want their buildings to include all amenities and have a ‘wow’ factor. Forest Lake Gardens in Hamilton New Zealand now houses a recreational facility and was constructed economically and quickly using Hyspan and Hybeam by futurebuild.

This permitted considerable cost savings, as the LVL pre-fabrication could occur off site whilst the steel structure was erected. This combination of timber and steel allowed the building to be put up very quickly and within the budget.

The design of this complex was not a conventional rectangular shape and therefore required an innovative approach. LVL timber was a very suitable alternative to steel as it was flexible to meet the curved design of the building. Lateral stability to the imposed loads was permitted through the combination of materials and framing systems – A masonry core at one end, steel portal frame at the other and timber LVL frame sandwiched between. This allowed the positive attributes of all the materials to be integrated.

Hyspan (600mm x 62mm lengths) can span a distance of 8m and if required to span further can be double up. These are connected to the steelwork and masonry wall simply using bolted proprietary systems. Architecturally the structural elements have being left exposed to feature as design elements. I personally think this technique is a very effective and visually pleasing one and works well within this scheme.

Torquay Apartments

Based on Boston Road in Torquay, although a residential project, this site visit was still one of interest as concrete and steel are the primary structural materials. We were unable to talk to the project manager as work was temporary suspended at the time we visited however it looks like a steel frame system is being combined with load bearing tilt up concrete construction.

An example of how a steel stanchion is bolted to the concrete panel via cleats. The wall panel is supported by strip footing and placed approx 75mm below ground level.

Below is a detail to show how the rafter and purlins are connected by M24 bolts. It also shows how fly bracing is placed on alternate rafters for extra support to the purlins. Steel rods have been used for cross bracing to resist lateral loads that may be imposed by external forces.

Here shows how the end structure is purely steel framing exemplifying how the corner assembly works. I am assuming by the artists impression of the final building that this structure will be covered by some form cladding and then plastered. Below is a good example of how the UB 320 rafter is connected to the wall panel by angle plates and 6 bolts. It is also clear the comparative size of the purlins to the rafter.

Spotlight -Breakwater/Belmont

Located on the Princes Highway at the Belmont and Breakwater inter-junction is the construction of a new multi-storey shopping complex. It is intended to be storage warehouse for Spotlight along with a number of other shops and an underground carpark.

Wall to Ground connection – Cast in steel wall ties placed two per panel at each end, with the grout poured through a grouting tube to seal the two panels together. Concrete is then poured on top of this plate to ensure strength and a smooth finish.

Panel to Panel connection – Steel plate bolted to both panels with concrete poured over the top. The openings in the plate for the bolts have being extended to allow for lateral movement of the concrete.

A detail to show how the universal rafter beam connects to the ‘c’ girt through a bolted plate. Also showing how the cross bracing is connected at this junction by a panel and how the corrugated roofing sits on top. The steel columns to support these rafters have been spaced at 8m in length ways and 19m in width allowing for a relatively column free floor area.

These panels were pre fabricated by a local company and transported via truck. Therefore curing has only ready occurred with the minimum time being four days. The advantage of this method allows a higher degree of finish. It also would be a quicker process off site as the set up is already in place however does require more energy in transportation. The opening for the panel would have been pre formed allowing for the frame and glazing to put in at a later stage.

The panels are lifted into place using a heavy duty crane. OHS regulations state that the radius of the height of the crane must be roped off and nobody is allowed to work within this area whilst the machine is in use. Once in place the panels are supported by steel props and may only be removed after being checked by an engineer.

Research on Louis Kahn

Design:
Working with simple materials, notably brick and concrete. Kahn applied his principles to create buildings instilled with the spiritual qualities for which he strove through a masterful sense of space and light. Kahn combined visually compelling spaces with drama as the changing light transformed the sensory experience of being in the building at different times of the day and night. In terms of injecting Kahn's spirit into our own warehouse project we are looking at incorporating the circular and geometric shapes used in the Sher-e-Bangla Nagar, into the concrete walls. Below are images used as a source of inspiration for our design.
Construction:
We are using concrete as our primary material and there are a number of construction methods that can be adapted to incorporate Kahn's ideals. The best alternative solution to steel portal frames is a concrete load-bearing wall with a lightweight roof. This is a very straightforward design and construction approach that can be easily adapted. The load-bearing walls can be either propped or cantilevered. For the propped wall, the stability comes initially from push-pull props. When the roof is complete the props are removed as the roof then provides the propping force and takes the horizontal loads back to the flank walls. For the cantilevered option, the walls cantilever from the base and do not need any propping or reliance on the on the roof for stability.The construction of the roof is also simplified with concrete walls as, unlike with steel portal frames, the roof beams are simply supported on the walls. The spacing of the roof beams could be optimised as they would not be reliant on the portal frame spacing. Roofs may be light or heavyweight. A heavyweight roof would provide extra thermal insulation and mass.

Burwood Campus - Canopy section

Burwood Campus - Parapet detail to end wall

Quicksilver HQ - Roof junction detail

Quicksilver HQ - Gutter detail