## Allowance for imperfections

- shall be assumed for the full height of the wall to allow for construction imperfections, where hef is the effective height of the wall. Locally under the bearing of the concentrated load, the design compressive stress shall not exceed the following values Walls built with Group 1 masonry units (not shell bedded) k (1 + 0,15 x) (1,5 - 1,1 M k

## Characteristic shear strength of unreinforced masonry

The characteristic shear strength fvk of unreinforced masonry can be determined - from the results of tests on masonry, - by calculation in the following way For general purpose mortar and when all joints may be considered as filled, fvk will not fall below the least of the values described below fvk fvko + 0,4 Sd or 0,065 fb, but not less than fvko or the limiting value given in table 3.5 fvko is the shear strength, under zero compressive stress sd is the design compressive stress...

## Classification in terms of manufacturing control

Category I - specified mean compressive strength, - probability of failing is not exceeding 5j , - tested in accordance with EN 771 and EN 772-1. Category II - mean compressive strength complies with the declaration in accordance with EN 771, - additional requirements for category I are not met. Natural stone units should be considered as Category II units. Masonry units should be grouped as Group 1, Group 2a, Group 2b or Group 3 Table 3.1 Requirements for grouping of masonry units. Table 3.1...

## Effects of openings chases and recesses in walls

(1) If the stiffened wall is weakened by vertical chases and or recesses, other than those allowed by table 5.3, - the reduced thickness of the wall should be used for t - or a free edge should be assumed at the position of the vertical chase or recess. A free edge should always be assumed, when the thickness of the wall, remaining after the vertical chase or recess has been formed, is less than half the wall thickness. with a clear height of more than 1 4 of the storey height, or a clear width...

## Stiffened walls

1 Walls may be considered as stiffened at a vertical edge if and its stiffening wall is not expected, i.e. - both walls are made of materials with approximately similar deformation behaviour, - are approximately evenly loaded - are erected simultaneously and bonded together - and differential movement between the walls for example, due to shrinkage, loading etc., is not expected, the connection between a wall and its stiffening wall, is designed to resist developed tension and compression...

## Reduction factor for slenderness and eccentricity

I At the top or bottom of the wall. ei is the eccentricity at the top or the bottom of the wall M Mi is the design bending moment at the top or the bottom of the wall resulting from the eccentricity of the floor load at the support, according to 4.4.7 see figure 4.1 , ehi is the eccentricity at the top or bottom of the wall, if any, resulting from horizontal loads for example, wind , ea is the accidental eccentricity see 4.4.7.2 , Figure 4.1 Moments from calculation of eccentricities. Figure...

## Verification of unreinforced masonry walls

1 The design vertical load resistance of a single leaf wall per unit length, NRd, is given by Fim is the capacity reduction factor Fi or Fm, as appropriate, allowing for the effects of slenderness and eccentricity of loading fk is the characteristic compressive strength of masonry gM is the partial safety factor for the material taking into account the depth of recesses in joints greater than 5 mm. 2 The design strength of a wall may be at its lowest - in the middle one fifth of the heigth,...

## Modulus of elasticity

1 P The short term secant modulus of elasticity, E, shall be determined by tests in accordance with eN 1052-1 at service load conditions, i.e. at one third of the maximum load determined in accordance with EN 1052-1. 2 In the absence of a value determined by tests in accordance with EN 1052-1, the short term secant modulus of elasticity of masonry, E, under service conditions and for use in the structural analysis, may be taken to be 1 000 f 3 When the modulus of elasticity is used in...

## Analysis of shear walls

For the analysis of shear walls, the design horizontal actions and the design vertical loads shall be applied to the overall structure. This causes the following situation of the individual shear wall The most unfavourable combination of vertical load and shear should be considered, as follows - maximum axial load per unit length of the shear wall, due to vertical loads and considering the longitudinal eccentricity due to cantilever bending, or - maximum axial load per unit length in the...

## Characteristic flexural strength of unreinforced masonry

determinated from the results of tests on masonry - fxk1 failure parallel to the bed joints, - fxk2 failure perpendicular to the bed joints. - only for transient loads for example wind - fxk1 0, where failure of the wall would lead to a major collapse. fxk1 and fxk2 will be given in the NAD's fxk1 Plane of failure fxk2 Plane of failure parallel to bed joints perpendicular to bed joints Determination of the flexural strength by tests Examples of test set-ups and of typical test specimens for W...

## Outofplane eccentricity General

The out-of-plane eccentricity of loading on walls - from the material properties given in Section 3, - and from the principles of structural mechanics. A simplified method is given in Annex C - the joint between the wall and the floor may be simplified, by using uncracked cross sections - elastic behaviour of the materials A frame analysis or a single joint analysis may be used. Joint analysis may be simplified as shown in figure C.1 Figure C.1 Simplified frame diagram For less than four...