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RECO2006 Construction IV

Shoring

Edward CY YIUDepartment of Real Estate and Construction

January 2007

Learning Objectives

• What is shoring• Why shoring• Types of shoring

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What is shoring?• Shoring (from "shore," a prop) is an operation

connected with building. It is often necessary before actual building is begun to support adjoining premises while the work of excavatingfor underground apartments is being carried out.

• The art of shoring comprises the temporary support of buildings, and may become necessary because of the failure or settlement of some portion of the structure or for the purpose of upholding the upper portion while alterations are being made in the lower.

http://en.wikipedia.org/wiki/Shoring Propping = Bracing = Retaining Wall = Shoring?

Shoring Materials• There are several different forms of shoring, each

adapted to suit peculiar circumstances.

• Much of the shoring for ordinary cases is done with heavy, roughly sawn timbers strongly braced together, but for especially heavy work steel members may be introduced and prove of great value.

• There is the trouble in connection with their use, however, that connections between steel members are not made with the same facility as between pieces of timber.

http://en.wikipedia.org/wiki/Shoring

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Types of Shoring• The most general shoring is the raking shore.

– It consists of one or more timbers sloping from the face of the structure to be supported and bedded upon the ground.

– As the ground is usually of a more or less yielding nature, a stout timber plate termed a sole-piece, of sufficient area to withstand being driven into the soil, is placed to receive the base of theraking timber or timbers.

– A wall-plate, with the object of increasing the area of support, is fixed to the face of the wall by means of hooks driven into the wall.

– Where space is available, an angle of 60° is the best to adopt for the main shore, the auxiliary members ranging in their slope from 45° to 75°.

– In many cases, especially in towns, the angle of slope is governed by outside influences such as the width of the footway.

http://en.wikipedia.org/wiki/Shoring

Types of Shoring (Cont’d)• Flying Shores

In some situations, the close proximity of existing buildings, or the need to maintain access, may prevent the use of raking shores. In these situations, a flying shore may be effective.

• This relies on transmitting loads to the adjacent structures, for which obviously the owner's permission will be necessary.

• The existing building to be used for support should also be carefully inspected for its adequacy to carry additional loads.

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Types of Shoring (Cont’d)• Deed or Needle Shoring

Dead or needle shoring, often more simply referred to as propping, is used for supporting existing walls, floors and roofing whilst works are carried out to form openings or remove walls at lower level.

• Steel or timber uprights are provided to support loads from a structure, normally in association with wedges or head and sole plates to distribute stresses over larger areas.

Type of Shoring (Cont’d)

• Sheet Piling– For a continuous

support of soil against collapse

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Examples of Sheet Piling

Sheet piling works at Fanling WSD Reserved Area for the construction of noise barrier foundation

http://www.hyd.gov.hk/contractwebsites/fhnb/HY200320_FILES/PHOTO0501.HTM

Type of Shoring (Cont’d)

• Diaphragm Wall• Cofferdam

• Are these shoring?

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Example of Propping - Source: http://www.sciglobal.com/falsework/20KPostShore.html

Source: http://www.sciglobal.com/falsework/20KPostShore.html

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Hyd Shoring Guidelines

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Diaphragm Wall – shoring?• Diaphragm wall can be made of reinforced concrete to

provide structural load-bearing elements for temporary or permanent retaining walls or both.

• Cofferdam is a temporary structure built to exclude earth and water from construction area and thus permit the work inside the cofferdam to be carried out in the dry.

• Retaining wall is …

• Refer to course materials on civil works

Cofferdam in IFC2

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References

• PNAP 142, 166 – Retaining Walls• Building (Construction) Regulations, (Cap.

123), Laws of Hong Kong• HD (2003) Guide to Trench Excavation

(Shoring Support and Drainage Measures), Highways Department, H

The End

For enquiries, please send email to Edward CY YIU

Department of Real Estate and ConstructionThe University of Hong Kong

ecyyiu@hkucc.hku.hk