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

Bonding of masonry

(1)P Masonry units shall be bonded together, with mortar in accordance with proven practice. should be overlapped on alternate courses, so that the wall acts as a single structural element overlap > 0,4 Um or 40 mm, whichever is the greater Figure 5.7 Overlap of masonry units. At corners or junctions the overlap of the units, should not be less than the thickness of the units, cut units should be used, to achieve the specified overlap in the remainder of the wall.

Characteristic compressive strength of unreinforced masonry made using lightweight mortar

(1) The characteristic compressive strength of unreinforced masonry, fk, made with Group 1, 2a and 2b masonry units and lightweight mortar, with all joints to be considered as filled, may be calculated using equation (3.3) provided that fb is not taken to be greater than 15 N mm2 and that there is no longitudinal mortar joint through all or part of the length of the wall. - the density of the used lightweight mortar, - the type of the masonry units. characteristic compressive strength of...

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...

Compressive strength of masonry units

The normalized compressive strength fb shall be used in design. Compressive strength is tested in accordance with EN 772-1 - The tests are carried out with a certain number of single units, - When quoted as the mean strength, it should be converted to fb by multiplying by the factor d to allow for the height and width of the units. (d is a form factor, as the test results depend on the relation of the height to the horizontal dimension of the units). - When quoted as the characteristic...

Creep shrinkage and thermal expansion

Table 3.8 Deformation properties of unreinforced masonry made with general purpose mortar Table 3.8 Deformation properties of unreinforced masonry made with general purpose mortar Final creep coefficient (see note 1) Final moisture expansion or shrinkage (see note 2) Dense aggregate concrete and manufactured stone 1. The final creep coefficient 4> c eel , where eca> is the final creep strain and Ee, a E. 2. Where the final value of moisture expansion or shrinkage is shown minus it indicates...

Design of structural members

(1)P The design of members shall be verified in the ultimate limit state. (2)P The structure shall be designed so, that cracks or deflections, which might damage facing materials, partitions, finishing's or which might impair water-tightness, (3) The serviceability of masonry members, should not be unacceptably impaired, by the behaviour of other structural elements, such as deformations of floors, etc.

Design value of permanent actions

(1)P In the various combinations defined above, those permanent actions that increase shall be represented by their upper design values, those that decrease the effect of the variable actions (2)P Where the results of a verification may be very sensitive to variations of the magnitude of a permanent action from place to place in the structure, the unfavourable and the favourable parts of this action shall be considered as individual actions. This applies in particular to the verification of...

Distinction between principles and application rules depending on the character of the individual clauses

- general statements and definitions for which there is no alternative, - requirements and analytical models for which no alternative is permitted unless specifically stated. The principles are defined by the letter P, following the paragraph number, for example, (1)P. The application rules are generally recognised rules which follow the principles and satisfy their requirements. It is permissible to use alternative design rules differing from the application rules given in this Eurocode,...

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...

Method of design for a wall supported along edges

And there is an orthogonal strength ratio depending on the unit and the mortar used. The calculation of the design moment, Md, should take this into account and may be taken as either Md a Wk gF L2 per unit height of the wall Md m a Wk gF L2 per unit length of the wall when the plane of failure is perpendicular to the bed joints, ie. in the fxk2 direction, when the plane failure is parallel to the bed joints, ie. in the fxk1 direction fxk1 Plane of failure parallel to bed joints a is a bending...

Representative values of variable actions

(1)P The main representative value is the characteristic value Qk. (2)P Other representative values are expressed in terms of the characteristic value Qk by means of a coefficient yi. These values are defined as (3) Supplementary representative values are used for fatigue verification and dynamic analysis. (4)P The coefficient y is specified - in ENV 1991 or other relevant loading codes, or - by the client or the designer in conjunction with the client, provided that the minimum provisions...

Serviceability limit states

Or a function of certain design properties of materials related to the design effects of actions considered, determined on the basis of one of the combinations defined below. (2)P Three combinations of actions for serviceability limit states are defined X Gk,j ( + P) + Vl,1 Qk,1 + X V2,i Q (5) For building structures the rare combination may be simplified to the following expressions, which may also be used as a substitute for the frequent combination - considering only the most unfavourable...

Stiffened walls

Stiffening Wall

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...

Insertion

Semi Probabilistic Safety Concept

On the background of the semi probabilistic safety concept, looking at only one action S and one resistant value R The difference R - S in an actual case indicates the actual margin of safety. As the distributions of S and R are overlapping, it is possible, that R - S becomes lt 0, which means failure of the structure The safety factors have to be chosen such that the probability of failure is small enough to be tolerated.

Verification of unreinforced masonry walls

Double Leaf Wall Faced Wall

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

Loads Silo 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...

General

Load Transfer Masonry Structures

1 P The characteristic compressive strength of unreinforced masonry, fk, shall be determined from the results of tests on masonry. 2 The characteristic compressive strength of unreinforced masonry - may de determined by tests in accordance with EN 1052-1, - or it may be established from an evaluation of test data, based on the relationship between the characteristic compressive strength of unreinforced masonry, and the compressive strengths of the masonry units, and the mortar. In masonry...

Characteristic flexural strength of unreinforced masonry

Flexure Joints

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

Elastic Behaviour End Joint

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...

Design values of actions

1 P The design value Fd of an action is expressed in general terms as Ad gA Ak if Ad is not directly specified where gF, gG, gQ, gA and gp are the partial safety factors for the action. 3 P The upper and lower design values of permanent actions are expressed as follows - where only a single characteristic value Gk is used then Gd ,sup gG,sup Gk Gd ,inf - gG,inf Gk - where upper and lower characteristic values of permanent actions are used then Gd ,sup gG,sup Gk ,sup Gd ,inf gG,inf Gk ,inf

Determination of effective height

1 The effective height hef can be taken as pn is a reduction factor where n 2, 3 or 4 depending on the edge restraint or stiffening of the wall. 2 The reduction factor, pn , may be assumed to be I For walls restrained at the top and bottom by reinforced concrete floors or roofs spanning from both sides at the same level or by a reinforced concrete floor spanning from one side only and having a bearing of at least 2 3 the thickness of the wall but not less than 85 mm 0,75 unless the...

Partial safety factors for actions on building structures

Safety Factor Steel Structures Eurocode

Table 2.2 Partial safety factors for actions in building structures for persistent and transient design situations Table 2.2 Partial safety factors for actions in building structures for persistent and transient design situations For accidental design situations the partial safety factor For accidental design situations the partial safety factor for variable actions is equal to 1,0 3 By adopting the g values given in table 2.2, the following simplified combinations may be used - considering...