Castings for tubular members

Castings are particularly suitable for connections between tubular members because:

Von Gerkan Marg And Partners Stuttgart
11.10 Tubular connections of 'trunk' to 'branch' at Stuttgart Airport (architect: Von Gerkan Marg & Partners)

• the cost of profiling and welding complex tubular connections can be very high

• there are often a large number of connections of the same external dimensions in a large project

• complex hangar and node details can be formed easily

• cast connections are aesthetically more pleasing, as they are smoother in shape, and are accurate in dimensions

• toughness and fatigue resistance can be improved.

Examples of the use of castings in connections between tubular members are:

• cast steel saddles and at the head of columns

• tension connections

• noded connections in multi-planar trusses

• junctions between columns and sloping members, as in the column 'tree' of Figure 11.10

• true pinned connections, as in Figure 11.11.

Cast Steel Connections
11.11 Casting for pinned connections at Ponds Forge, Sheffield (architect: FaulknerBrowns)
Tubular Column Branch

11.12 Stainless steel node to the tubular arms at Aix en Provence TGV station (architect: AREP-SNCF and Arcora)

Cast Steel Connections

At Stansted Airport, the design team decided that the majority of connections could be made by castings. At Stuttgart Airport, castings were used to connect the 'trunk' to the 'branches', as illustrated in Figure 11.10.

At the TGV station in Aix en Provence, France, cast steel forked nodes connected the columns to the inclined tubular arms that supported the roof, as illustrated in Figure 11.12.

Chapter 12

Corrosion protection

The cost of corrosion protection can be as high as 20% of the total cost of fabricated steelwork, and it is therefore important not to over-specify the protective system, whilst achieving an acceptable life to

first maintenance. Corus has prepared various publications to assist the designer in the protection strategy. The following notes supplement the guidance given by Corus.

Corrosion of steel can only occur if both oxygen and water are present. The rate of corrosion will depend on the exposure and on the concentration of containments (usually chlorides and sulphides) in the atmosphere. Thus, permanently embedded steel piles do not corrode, even though they are in contact with water, provided that air is excluded by the impermeability of the soil. Similarly, the interior faces of tubular sections will not corrode, provided they are sealed.

Within buildings, only minor and superficial oxidation may occur, except in areas such as roofing or cladding, which may be subject to condensation or water leakage.

Greener Homes for You

Greener Homes for You

Get All The Support And Guidance You Need To Be A Success At Living Green. This Book Is One Of The Most Valuable Resources In The World When It Comes To Great Tips on Buying, Designing and Building an Eco-friendly Home.

Get My Free Ebook

Post a comment