O slideshow foi denunciado.
Seu SlideShare está sendo baixado. ×

Industrial construction

Anúncio
Anúncio
Anúncio
Anúncio
Anúncio
Anúncio
Anúncio
Anúncio
Anúncio
Anúncio
Anúncio
Anúncio
Próximos SlideShares
Prefabrication in construction
Prefabrication in construction
Carregando em…3
×

Confira estes a seguir

1 de 20 Anúncio

Mais Conteúdo rRelacionado

Diapositivos para si (20)

Semelhante a Industrial construction (20)

Anúncio

Mais recentes (20)

Industrial construction

  1. 1. Charlie Gupta B.Arch VIII Sem
  2. 2. A truss is essentially a triangulated system of straight interconnected structural elements. The most common use of trusses is in buildings, where support to roofs, the floors and internal loading such as services and suspended ceilings, are readily provided. The main reasons for using trusses are:  Long span  Lightweight  Reduced deflection (compared to plain members)  Opportunity to support considerable loads
  3. 3. Trusses are used in a broad range of buildings, mainly where there is a requirement for very long spans, such as in airport terminals, aircraft hangers, sports stadia roofs, auditoriums and other leisure. Trusses are also used to carry heavy loads and are sometimes used as transfer structures. This article focuses on typical single storey industrial building, where trusses are widely used to serve two main functions: • To carry the roof load • To provide horizontal stability.
  4. 4. • The members of trusses are made of either rolled steel sections or built-up sections depending upon the span length, intensity of loading, etc. Rolled steel angles, tee sections, hollow circular and rectangular structural tubes are used in the case of roof trusses in industrial buildings • In long span roof trusses and short span bridges heavier rolled steel sections, such as channels, I sections are used • Members built-up using I sections, channels, angles and plates are used in the case of long span bridge trusses
  5. 5.  In the first case the lateral stability of the structure is provided by a series of portal trusses; the connections between the truss and the columns provide resistance to a global bending moment. Loads are applied to the portal structure by purlins and side rails  In the second case, (right) each truss and the two columns between which it spans, constitute a simple structure; the connection between the truss and a column does not resist the global bending moment, and the two column bases are pinned. Longitudinal stability is also provided by a wind girder in the roof and vertical bracing in the elevations.
  6. 6. Trusses comprise assemblies of tension and compression elements. Under gravity loads, the top and bottom chords of the truss provide the compression and tension resistance to overall bending, and the bracing resists the shear forces. A wide range of truss forms can be created. Each can vary in overall geometry and in the choice of the individual elements. Some of the commonly used types are shown below Pratt truss ('N' truss) • Pratt trusses are commonly used in long span buildings ranging from 20 to 100 m in span. In a conventional Pratt truss, diagonal members are in tension for gravity loads. This type of truss is used where gravity loads are predominant . • An alternative Pratt truss is shown where the diagonal members are in tension for uplift loads. This type of truss is used where uplift loads are predominant, which may be the case in open buildings such as aircraft hangers.
  7. 7. It is possible to add secondary members in Pratt truss to: • Create intermediate support points for applied loads • Limit the buckling length of members in compression (although in a 2D truss, the buckling length is only modified in one axis).
  8. 8.  When the floor span exceeds 15m, it is generally more economical to change from a simple truss arrangement to one employing wide span lattice girders which support trusses at right angles.  In order to light up the space satisfactorily, roof lighting has to replace or supplement, side lighting provision must also be made for ventilation form the roof.  One of the oldest and economical methods of covering large areas is the North Light and Lattice girder.  This roof consists of a series of trusses fixed to girders. The short vertical side of the truss is glazed so that when the roof is used in the Northern Hemisphere, the glazed portion faces North for the best light.  It can be used for spans from 20-30m.  Used for industrial buildings, drawing rooms etc.
  9. 9.  A lattice girder is a type of girder with a criss-crossed web design, such as in gardening lattices, between the two edges of the girder.  The diagonal lines of steel give support in all directions, helping to prevent the girder, which is one of the main support elements in a bridge design, from bending.  Often seen on older bridges or buildings, lattice girders are also widely used in mining tunnels for roof support during excavations and can be erected quickly.  Lattice girders are not used so much in building or bridges anymore as they have been replaced by solid steel plate girders
  10. 10. Trusses consume a lot less material compared to beams to span the same length and transfer moderate to heavy loads. However, the labour requirement for fabrication and erection of trusses is higher and hence the relative economy is dictated by different factors. In India these considerations are likely to favor the trusses even more because of the lower labour cost. In order to fully utilize the economy of the trusses the designers should ascertain the following:  Method of fabrication and erection to be followed, facility for shop fabrication available, transportation restrictions, field assembly facilities.  Preferred practices and past experience.  Availability of materials and sections to be used in fabrication.  Erection technique to be followed and erection stresses.  Method of connection preferred by the contractor and client (bolting, welding or riveting).  Choice of as rolled or fabricated sections.  Simple design with maximum repetition and minimum inventory of material.
  11. 11.  Portal frames are a type of structural frame, that, in their simplest form, are characterised by a beam (or rafter) supported at either end by columns, however, the joints between the beam and columns are 'rigid' so that the bending moment in the beam is transferred to the columns.
  12. 12. Portal Frames are generally used for single storey construction which require a large unobstructed floor space ie Factories Shopping Centres Warehouses Portal frames are made in a variety of shapes and sizes. They are usually made from steel, but can also be made from concrete or timber. The portal structure is designed in such a way that it has no intermediate columns, as a result large open areas can easily be created within the structure.
  13. 13. Advantages  Speed and ease of erection  Building can be quickly closed in and made water tight.  Framework prefabricated in a workshop and not affected by weather.  Site works such as drainage, roads etc can be carried out until framework is ready for erection.  No weather hold up during erecting the framework.  Connected together in factories by welding and site connections should be bolted. Disadvantages  Although steel is incombustible it has a poor resistance to fire as it bends easily when hot.  Subject to corrosion
  14. 14.  A high percentage of roofs are covered with composite profile metal sheets with a coloured external skin.  These composite sheets have approximately 50mm of insulation sandwiched between two thin metal sheets or aluminium sheets. Coated steel is lowest in cost but limited in life due to the durability of the finish. Aluminium develops its own protective film. Profile sheets are quick to erect, dismantle and repair.  Galvanised steel purlins span between the steel rafters.  Wall panels
  15. 15.  Shown here is a ridge joint or apex joint.  It is Important that this joint is strong hence the use of wedge shaped pieces called gusset pieces to strengthen and increase the bolt area.
  16. 16. KNEE JOINT FOR PORTAL FRAME  Again the knee joint must be strong to support the roof loads and prevent bending.  Gusset pieces will be used to increase strength, give greater bolt area and prevent deflection under load
  17. 17.  With all types of frameworks we must think on stability ie movement. To help strengthen the framework and prevent movement diagonal bracing will be used
  18. 18.  This slide shows the cladding rails for attaching the external metal cladding panels to.  These rails can be fixed horizontal or vertical depending on the way the cladding panels are fixed
  19. 19.  These wire and tubular ties are used to prevent sagging of the cladding rails which can add considerable force unto the joints of the external cladding.
  20. 20.  Here we see the finish of the external cladding panels with the lower level facing brickwork.  The blockwork behind creates a protective wall or firewall.

×