Name: Darren Newsham Student no: st20094701

Steel Frame Construction.

FoundationsAs with any type of construction it is important to consider the substructure, this is referred to as anything below ground level but not including the ground floor bed (as well as all structure that is below the superstructure).

This is where we consider the foundations, whose function is to safely sustain / transmit combined dead, imposed and wind loads to the ground on which it rests upon. This must be done in such a manner as not to cause

Settlement

Movement

Failure to do this would impair structural stability and could cause damage to any part of the building.

The size of a foundation is dependent basically on two factors

1. The bearing capacity of subsoil under the proposed foundation

2. The load being transmitted

Most foundation types, except for simple domestic foundations, will be constructed with reinforced concrete and referred to as being deep or shallow. Shallow foundations are mostly constructed within 2 m of ground level, in some instances it is necessary to go deeper, if foundations are needed to be taken below 5 m it would be cheaper to do this if designed and constructed as a pile foundation.

One way to describe piled foundations is that, these are a series of columns that are constructed / inserted into the ground to transmit the structure load to a lower level of subsoil.

Other than economic reasons pile foundations may be used because of:

Module ADZ5000 [Type here] Architectural Design & Technology

Name: Darren Newsham Student no: st20094701

natural load-bearing capacity of subsoil

high water table

compressible subsoil such as Pete recently placed filling materials are present

subsoil that is subject to moisture movement or plastic failure

Piles may be classified by their construction method or design function.

Module ADZ5000 [Type here] Architectural Design & Technology

Name: Darren Newsham Student no: st20094701

Module ADZ5000 [Type here] Architectural Design & Technology

Name: Darren Newsham Student no: st20094701

Module ADZ5000 [Type here] Architectural Design & Technology

Name: Darren Newsham Student no: st20094701

Module ADZ5000 [Type here] Architectural Design & Technology

Name: Darren Newsham Student no: st20094701

Module ADZ5000 [Type here] Architectural Design & Technology

Name: Darren Newsham Student no: st20094701

FrameworkFor low storey construction, portal frames are an ideal choice - these are two-dimensional rigid frames which act as a rigid joint between the column and beam. Its purpose is to reduce bending moment in the beam allowing for the frame to act as one structural unit.

Often stresses from the beam to the column can result in rotational movement at the foundation. This can be overcome by the introduction of a pin or hinge joint.

Medium to high rise construction, (residential apartments, hotels and office blocks), require something more substantial to take into consideration wind forces and added loads that need to be transmitted through the structural frame.

Framed buildings are suitable for this purpose and the main type used for this type of structure is a skeleton frame. The benefits for their use include:

the small area of frame maximises the usable floor area of the building.

The lack of massive structure, which would normally restrict the use of floor areas, allows greater flexibility in the use of the building by providing large areas of open floor

it is normally accepted that the use of frame structures results in savings in time and cost over load-bearing forms

It is necessary to use a structural frame when constructing buildings of height otherwise a load-bearing structure would be enormous at its lower level to support its upper levels.

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Name: Darren Newsham Student no: st20094701

Skeleton frames are a series of rectangular frames placed at right angles to one another to enable loads to be transmitted from member to member until transferred successfully through the foundations to the subsoil.

Types of frames

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Sections and Base Plate Hot rolled steel is commonly used for the structural steelwork standard sections such as columns and beams. Cold rolled steel has replaced the former for use in sub-framing (joists, purlins, sheeting rails etc.). Cold rolled steel is also lighter which makes it a good alternative to hot rolled as it saves on:

materials

transportation

building dead load

Compound sections are produced by welding together standard sections producing various profiles that can be designed specifically for extreme situations where standard sections would not be sufficient, such as long spans and very high loads.

Structural steelwork connection is either done in the workshop or on site. Site connections are mostly bolted together whereas workshop connections are often carried out by welding. Structural engineers are responsible for the design of structural steelwork members and all its connections, they select the type / number of boats or the size / length of weld needed to achieve the connection strength required.

Types of weld include:

butt weld

fillet weld

A base plate is used at the foot of a column, the type of plate selected will depend on the load carried by the column as well as the distribution area of the plate. The cross-sectional area of the universal column concentrates the load into a relatively small part of the base plate itself. To resist bending or sheer the base must be designed to resist column loads and transfer them onto the foundation below.

Module ADZ5000 [Type here] Architectural Design & Technology

Name: Darren Newsham Student no: st20094701

Module ADZ5000 [Type here] Architectural Design & Technology

Name: Darren Newsham Student no: st20094701

Fire ProtectionSteel maybe a non-combustible material with a negligible surface spread of flame properties but it does not behave very well under fire conditions. In the initial stages of a fire steel will gain in strength, then decrease to normal temperature range of 250 to 400°C. It will then continue to reduce until the still temperature reaches 550°C by which time it will have lost most of its strength.

During a fire, temperature rise is rapid, in terms of time structural steelwork will need protection to give it a specific degree of fire resistance. In relation to building usage and size, Part B of the Building Regulations sets out the minimum requirements. BRE Report 128 ‘Guidelines for the construction of fire resisting structural elements’ explains acceptable methods.

Profile Metal SheetingMetal sheets are pressed or rolled into various profiles to give the necessary stiffness to span between cladding rails, depending on the depth of the profile, that are spaced 2 to 3 m apart.

The choice of aluminium and steel for this purpose because they can be coated with various materials to give protection against the weather and provide a colour finish.

Some of these coatings permit profiling after the coating process, others do not.

These sheets are supported by cladding rails consisting of hot or cold formed steel angles or channels which are bolted to the structural frame where the sheeting is fixed through the troughs using self-tapping screws.

Some sheeting systems will have secret fixings incorporating concealed clips and interlocking edge joints to avoid fixing through the sheeting face.

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It is normal to have 100 to 200 mm sheeting overlaps and Z-flashings for end joints between the sheeting and door / window heads.

To achieve thermal insulation, it is possible to back the sheeting on site with rigid boards that will be either carried on supports fixed to the cladding rails or to the rails themselves. For the interior the same fixing method applies, but boards are usually covered with plasterboard or wall finish.

To protect the insulation from a reduction in its efficiency due to saturation by condensation, a vapour control layer is required under the liner on the warm side of the insulation and a breather membrane on the outside.

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Glass Sheeting

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References:

Building Construction HandbookEleventh Edition, Published 2016

By Roy Chudley and Roger Greeno

Routledge, Taylor & Francis Group, LONDON AND NEW YORK

ISBN13: 978-1-138-90709-6 (pbk)

ISBN13: 978-1-315-69517-4 (ebk)

Construction technology 2Industrial and commercial buildingFirst Edition, Published 2004

By Mike Riley and Alison Cotgrave

Palgrave, Macmillan

ISBN-10: 0-333-80482-1

ISBN-13: 978-0-333-80482-7

Structure and ArchitectureSecond Edition, Published 2001, Reprinted 2002;2003;2005;2007;2008

By Angus J Mcdonald

Department of Architecture, University of Edinburgh

Architectural Press, Oxford, Auckland, Boston, Johannesburg, Melbourne, New Delhi

ISBN: 978-0-7506-4793-9

References (continued):

Module ADZ5000 [Type here] Architectural Design & Technology

Name: Darren Newsham Student no: st20094701

Mitchell’s Structure & Fabric Part 1Sixth Edition, Published 2000

By Jack Stroud Foster

Longman, Pearson Education

ISBN-10: 0-582-40447-9

ISBN-13: 978-0-582-40447-2

Mitchell’s Structure & Fabric Part 2Sixth Edition, Published 2000

By Jack Stroud Foster & Raymond Harington

Longman, Pearson Education

ISBN-10: 0-582-40520-3

ISBN-13: 978-0-582-40520-2

Photos courtesy of Building Construction Handbook, Construction Technology 2, Structure & Fabric Part 2

Module ADZ5000 [Type here] Architectural Design & Technology