For more than a hundred years, the use of aluminum in fact proved, it is quite suitable material for bearing structures. However, for the design of these structures, in particular, designs of aluminum profiles, requires certain knowledge and experience.
Eurocodes (or better, may be, Eurocodes) are harmonized European standards (EN) for ghjtrnbhjdfybz building structures and structures. The complete set of Eurocodes includes ten standards (from Eurocode 0 to Eurocodes 9), each of which in turn is divided into parts, Total – 58 documents. Eurocodes are obligatory for the EU Member States, each country should adapt them to local conditions. To this end, developed National Annexes to Eurocodes. After each such adaptation Eurocode acquires the status of a national standard. Some CIS countries - Belarus and Kazakhstan – We have already made the transition to Eurocodes as alternative standards. Ukraine and Russia are preparing for their entry.
"Aluminum" Eurocode 9 (IN 1999)
It includes five parts. The most interesting for us is the first part - EN 1999-1-1:2007 – General design rules. EN 1999-1-1 gives the basic design rules using products from wrought aluminum alloys: extruded - profiles, pipes and rods, of cold - pipes, katanıh plate, sheets and strips, as well as the limited guidance for cast alloys.
Our “Eurocode 9” – SNIP 2.03.06-85
At present, Russia has a set of rules JV 128.13330.2012, which is the updated edition of the old domestic SNIP 2.03.06-85 “aluminum structures”.
This new edition 2012 year contains an increased number of both wrought aluminum alloys in comparison with the previous edition:
- heat-hardening alloys: AD31, AD33, AB, 6060, 6063, 1915, 1925, B95;
- work hardenable alloys: AD1, AMC, AMg2, AMg3,
- casting alloys: AK8M3ch, (VAL8), AK7ch (AL9) and AK9ch (AL4).
Steel and aluminum in the construction of
when an engineer, who worked with steels, begins to design a building aluminum structures, He faces two difficulties. The first is the large number of available aluminum alloys, each of which in addition may still be in different states. The second difficulty, and it can be a problem, It is, that finished aluminum products, especially profiles, rarely in warehouses sufficient. Nomenclature aluminum profiles, which lie in warehouses, often very limited and includes mostly only small standard profiles. The reason for this is, Unlike aluminum profiles, which are produced by "warm" pressing, steel profiles manufactured by hot rolling. For the rolling characteristic of the high cost of the rolls and a significant duration and the complexity of the transition to a different product mix. Therefore, to reduce the unit cost of production profitable enough to make large batches of the same steel profiles.
The cost of aluminum profiles
Cost matrices may be relatively low for extrusion of aluminum profiles. for instance, alloy type compression 6060 diameter of the workpiece 152 mm cheapest matrix, small, simple solid profile is worth about 600 euro, and the most expensive, for broad profiles with multiple cavities - about 3 thousand euros, the most complex – 5 thousand. Of course, with an increase in the diameter of the workpiece or the number of strands (threads) of pressing, the price may rise. However, in any case,, is less than the cost of a set of steel rolling rolls and a manufacturer in a short time - less than a month.
Therefore, economically viable minimum lot size of aluminum profiles can be very small - from 200 to 300 kg. This leads to, that many companies are developing their own aluminum profiles specially for specific designs to the peak of their functionality. Near 90 % All aluminum profiles designed for one customer only and are made for him. This partly explains, why so few ready-made aluminum profiles held in warehouses.
Aluminum in construction - know more
For an experienced engineer a choice of aluminum alloy, and his condition is not very difficult, especially if there is complete clarity on the following issues:
- What level of material strength is needed for aluminum profiles?
- Is it really necessary to have high strength of welded joints between aluminum profiles?
- How many sheets and profiles are needed and can it be in suppliers' warehouses?
- If you develop a special aluminum profiles, Is there enough of each of them for an industrial batch?
- Do you need increased requirements for dimensional accuracy and shape of aluminum profiles?
- Is there a need for high ductility of the material of aluminum profiles?
- Do you need a high forming and bending ability of sheets and profiles?
- Is decorative anodizing of aluminum profiles required?
- Are there any requirements for aluminum profiles in relation to elevated temperatures?
Last, but one of the most important questions: how much will these profiles cost? There is a significant difference in price between different alloys and semi-finished products, so engineers often have to modify your project to reduce the cost of the product or design.
This may explain, why the design of aluminum structures requires a lot more knowledge about aluminum as a material, than is the case when working with steel.
1. EN 1999-1-1:2007 Eurocode 9: Design of aluminium structures – Part 1-1: General structural rules.
2. lattice R. Structural Design according to Eurocode 9: Essential Properties of Materials and Background. – The Workshop in Brussels: EUROCODES – Background and Applications, 2008.