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Размещенно 28/02/2008 в 11:12 Автор Анонимка :(

Статья заслуживает внимания:
Popular Steel Building Systems in the 21st Century

There are many types of building systems on the market today. This article examines six of them.
The steel truss system has been very popular for many years in bridge and structure building. Steel roof trusses are very cost efficient for clear-span applications up to 140 feet. Steel trusses can be designed with double slopes deepening the section in the middle which is helpful structurally. Steel trusses depend on metal horizontal roof diaphragms and wall bracing for lateral stability. In today’s single steel truss approach a column in the truss work is erected first and then the truss to column connections are made.
Hot rolled steel rigid frames are beam and columns fastened together by connections. This is a unitized construction and bracing is no necessary. A number of single story buildings are made with this approach. The rigid frame has the advantage over many other systems. There is more efficient use of steel, cleaning and maintenance are simple when compared to truss construction, and heavier loads are more readily supported. The high unit cost along with settlement and temperature stresses are among the negatives.
Some industries favor “heavy” or “hybrid” structures for their particular applications. This is a popular choice for those companies needing multi-story capacity, greater span width, or sizeable cranes for their facilities. The term “hybrid” comes from the fact that these buildings utilize the traditional structural steel truss system for their primary framing, but the secondary components are all cold-formed steel. “Heavy” buildings are advantageous when framing deflections must be controlled to a precise level. This is true of such structures as wide-body jet hangars, movie complexes, and manufacturing concerns that utilize specific engineering. The steel trusses in these buildings can be cambered to exact requirements.
Beyond the arena of all-steel construction there are other systems that have become popular over the past years and compete with the traditional market for a wider share of business. One such system involves the use of laminated wood arches for construction. The structures are close to the overall function and design make-up of steel rigid frame construction. Where they differ is in the aesthetics of the inviting appearance of laminate wood to the sometimes cold starkness that steel frames convey. Roof decking of timber combined with the wood arches are popular choices for sanctuaries, municipal structures, and residential applications. Spans of these buildings are adequate in span and can have exaggerated roof pitches. Disadvantages of wood include insect infestation and rot.
Another system that has grown in popularity recently is pre-cast concrete. This is a more expensive process than steel but is more important to purchasers requiring sound abatement qualities and accentuated fire safety ability. This approach relies on pre-cast, hollow core planks and roof panels. The advantages include quickness of construction, single vendor accountability for framing work, and future expansion possibilities.

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