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Dissemination of information for training Brussels, 2-3 April 2009 1

EUROCODE 6Background and applications

EUROCODE 6Design of masonry structures

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EUROCODE 6Combined loading

Poul ChristiansenDanish Technological Institute

[email protected]

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Combined loading

Walls subjected to vertical

and lateral load

Walls supported by2 3 4 edges and withopenings

Edges restrained or simplysupported

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Distribution of wind load between outer and inner leaf

Either:1. A distribution between the outer andinner leaf.

or

2.The total wind load applied on theinner leaf, when (5.11) is used.

If 1. Either:A. According to the stiffness

B. According to the capacityWcap = Wcap,1 + Wcap,2 (6.3.1 (6))

In this example (5.11) is used

3 3

2

3

1tefef ttkt +=

21

1

1,1, )()(

)(

EIEI

EIWW

EdEd +=

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Horizontal and vertical load

Yield line theory is relevant for openings, 3-4 sided walls.- method is relevant for 2. order effects and wallssupported in top and buttom

The link between the methods is the equivalence of MEd.Thus an equivalent windload is introduced: Weqv ( Wed) (Annex I)

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Determining weqv

The apparent flexural strength: fxd1,app = fxd1 + (6.16)The moment of resistance: MRd = (1/6)(teff)

2 x fxd1,appBased on the yield line theory: Wcap is calculated

The actual moment due to (Wed): MEd = (WEd/ Wcap) x MRdLink: (1/8) x h2 x Weqv= MEd = (WEd/ Wcap) x MRdFinally: Weqv = (8/h

2) x (WEd/ Wcap) x MRd

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Determining the effective thickness

The thickness can be formally altered:

When formula 5.11 is used:

When table 5.1 is used:

When using both formulas

the expression will be:

=eft

3 32

31tefef ttkt +=

3 32t

31tefef )t(tkt +=

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Determining the effective height

For this example the effectiveheight will normally be setequal to the geometricallyheight. i.e.:

heff = h

In Eurocode 1996-1-1 thereare rules for determining

3 and 4, i.e. the reductionfactor for 3 and 4 sided sup-ported walls (without ope-nings). E.g.:

(5.8)

To implement openings follo-wing procedure can be used.

+

=24

l

h1

1

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Determining the effective height

The effective height is determined in sections

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Determining of the eccentricity

The main issue when regarding the eccentricity at the top (and the bottom) is thestiffness of the slab in the moment of fracture. The eccentricity can in practice bet/2 in favour of the construction or t/2 in disfavour of the construction. Theimplication for the load capacity is large.

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Determining of the eccentricity

The Danish approach is to define an interval of eccentricity producing an intervalfor the compression stress. For stiff slabs, foundation, etc the interval is thebearing length. For slack slabs it is half the bearing length.

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Determination of the compression zone

Determination of thecompression line/

zone after determi-ning heff, teff, Weqv,etc is done by theusually statically

methods.Wide of thecompression zoneis determined by fd

The shape of thecompression zoneis an affinity to themoment

The slack slabs with

an eccentricity indisfavour to theconstruction gives adecreased load

capacity.Here an area wherethe neccessity for fxd1is actual

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Determining the load capacity

To cover the spectraof eccentricities flis introduced in6.3.1 (4) (ii).

Here the extendedNavier expression isused to cover thearea of small Nand large M

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Final comments

Thank you for listening

Any later comments, etc to the papers:[email protected]

Computer program on the Internet fordesigning according to EN1996-1-1:

www.ec6design.com

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