Masonries Structures - Part III

8/21/2019 Masonries Structures - Part III

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8.3.2. Terms of Use(1) The restraints section of all structural walls, for horizontal forces computation, to which

defines the number of levels nnivwill be considered as follows:(a) at the top of the foundation structure for the building without basement;

(b) at the basement slab for dense walls buildings (Honeycomb system) and rare wall buildings

(cellular system) for which were provided additional walls in the basement (dense walls basement)in the idea to obtain a stiff and strength box;(c) above the foundation for walls for dense walls buildings (Honeycomb system) and rare wall

buildings (cellular system) for which were not provided additional walls in the basement (rare

walls basement);(2) The maximum number of levels above embedding section (nniv) of buildings with masonry

walls, to which the provisions of this Code, is limited by:

- Design ground acceleration at the site (ag);

- Class of regularity / irregularity as defined structure 8.3.3.;- Important class of building, established under 4.4.5;

- Type / composition masonry (ZNA, ZC, ZC + AR, ZIA);

-

Masonry group defined according to 8.2.1.(3) The density of masonry structural walls for buildings, interior + exterior, on each of the main

directions of the building is defined by the percentage ratio between the total net area of the walls

masonry (Az,net) on that direction, relative to floor area at that level (Apl)

(%)= 100,

8.3.2.1. Terms of use for structures with unreinforced masonry walls (ZNA/URM)

(1) Because of lower ability to dissipate seismic energy due to low tensile strength perpendicular

to the point of settlement and to the main tensile efforts, and reduced ductility impairments whowill conduct to brittle failures, we recommend the use of unreinforced masonry walls structures

(ZNA/URM) to be avoided.

(2) structures with unreinforced masonry walls (ZNA/URM) with masonry elements defined in

8.2.1 shall be used, as provided in Table 8.8, only if all the below conditions are fulfil:

(a) building qualify as "regularly building in plan and elevation";

(b) building falls in importance classes III or IV;

(c) the building have dense structural masonry walls (Honeycomb system);

(d) the level high hetaj 3.00 m;

(e) vertical and horizontal elements are provided to ensure the structural integrity of the

walls and 3d concurrence according to (4)

(f) the requirements for constructing masonry and floors of this Code are fulfil;

(g) the materials used satisfy the requirements from par.8.2 of this Code.

(3) the use of structures with unreinforced masonry structural walls (ZNA/URM) for buildings ofimportance classes I and II is not allowed in all seismic zones regardless of the number of levels

above section embedding (nniv).


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(4) The structure with unreinforced masonry walls with nniv 2 ( P +1 E) for seismic zones with

ag 0.25 g, regardless of the material, geometrical and mechanical characteristics of masonry,

shall be provided with RC beams and columns belts in the positions specified in 8.5.4.2.1. (1) Toensure the integrity of the whole building in different advanced solicitation stages under the effect

of earthquakes exceeding acceleration agset in Figure 3.1 for that site.

The strength of these elements will not be considered for calculation of design strength forstructural walls and even for assembly safety.

(5) The maximum number of levels above embedding section (nniv) for buildings with unreinforced

masonry structural walls (ZNA/URM) and the minimum constructive associated density of thestructural walls - (p%), on each of the main directions, depending of the design horizontal

acceleration (ag) are given in Table 8.8.

Table 8.8. - The maximum number of levels above embedding section and the minimum

constructive associated density of the structural walls - (p %) for unreinforced masonry walls

structures.

nniv

The design horizontal acceleration (ag)

0.10g and 0.15g 0.20g and 0.25g 0.30g and 0.40g

Burnt clay

from gr. 1

and 2

Burnt clay

from gr. 2S

and AAC

Burnt clay

from gr. 1

and 2

Burnt clay

from gr. 2S

and AAC

Burnt clay

from gr. 1

and 2

Burnt clay

from gr. 2S

and AAC

1 (P) 4.0% 4.5% 5.0% 5.5%

NA NA2 (P+1E) 4.5% 5.0% 5.5% 6.0%

3 (P+2E) 5.0% 5.5% NA NA

NAnot allowed the use of unreinforced masonry

(6) The values from Table 8.8 refers to the first level above the embedding section.

For all the other levels is allowed a wall density reducing up to 1 % per level keeping the regularlyconditions in elevation.

(7) In the case of buildings with ZNA/URM structural walls the attic and / or linked construction

(drying, washing, etc.) - as defined in 8.3.2.2 (5) shall be considered a "level" and must be included

in the total levels number admitted in Table 8.5 even if the special conditions for constructivecomposition from 8.3.2.2 (4).

(8) structures with unreinforced masonry structural walls (ZNA/URM) with masonry elements

defined in 8.2.1 can be used in all seismic zones without checking seismic design safety case for:- buildings with one level above the embedding section with household annexes function

that accommodate low value goods where people access is random;- Temporary buildings with lower utilization period of less than three years (for construction

site organization for example).


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Table 8.9. - The maximum number of levels above embedding section and the minimum

constructive associated density of the structural walls - (p %) for reinforced masonry walls

structures.

nniv

The design horizontal acceleration (ag)

0.10g and 0.15g 0.20g and 0.25g 0.30g and 0.40g

Burnt clayfrom gr. 1

and 2

Burnt clayfrom gr. 2S

and AAC


and 2


and AAC


and 2


and AAC

1 (P)3.0%

3.0%4.0%

4.0% 5.0% 5.5%

2 (P+1E) 3.5% 4.5% 5.5% 6.0%

3 (P+2E)4.0%

4.0% 5.0% 5.5% 6.0% 6.5%

4 (P+3E) 5.0% 6.0% 6.0% 6.5% **

5 (P+4E) 5.0%* 5.5%* ** ** ** NA

- For these situations ZC+AR or ZIA necessarily to be used** - Only for art. 8.3.2 (7) conditions

NAnot allowed the use of unreinforced masonry

(2) The density of structural walls set out in Table 8.9 refers to the first level above the embedding

section. For all the other levels is allowed a wall density reducing up to 1 % per level keeping the

regularly conditions in elevation.If by this reduction, regularity conditions are not satisfied, the base shear calculation will be done

using the modal method, as appropriate, using for computation 2D or 3D models in accordance

with Table 4.1 of the Code.

(3) In the seismic zones with ag=0,15g and ag=0,20g at least 75 % of the base shear force,

calculated in accordance with 8.4.2, should be taken with confined masonry structural walls with

RC column belts (ties) at both edges or reinforced core masonry walls. In seismic zones ag0,25gthe base shear force must be absorbed completely by confined masonry structural walls with RC

column belts (ties) at both edges or reinforced core masonry walls.

In both cases, position, size and reinforcement of the RC column belts (ties) must comply with thisChapter.

(4) In the case of buildings made with reinforced masonry (ZC, ZC+AR and ZIA) with a attic over

the last current level, it does not include this in the number of levels above maximum allowable

embedding section in Table 8.9 only if the following conditions constructive:

(a) The minimum wall constructive density from the Table 8.9 shall be increased by 1.0%;

(b) Perimeter masonry walls do not exceed the average height of 1.25 m;

(c) Partition walls are light type (gypsum-cartoon or similar);

(d) Wooden roof is designed so that it's not pushing out of plane the perimeter walls;

(e) The masonry structural walls in the attic is confined with RC column belts (ties) in the

continuation of the lower level;

(f) At the top of the attic masonry walls a RC beam belt (tie) is provided.


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If at least one of these conditions is not met, the attic will be considered "level" and the building

will fall, in terms of height and density of the structural walls, under the conditions given in Table

8.9.(5) When above the current top level slab of the building made with reinforced masonry (ZC,

ZC+AR and ZIA) are provided linked construction (drying, washing, etc.) occupying more than

20 % of the current level area and whose height is not greater than its height, these rooms areregarded as a prominent of the main building and will be treated as specified in (6) without beingconsidered as "level" within the limits given in Table 8.9.

(6) If the buildings referred to in (5) the calculation of shear forces by equivalent static method

will be as follows:(a) Base shear force (Fb) for the whole building (with total mass m) is calculated as

in 8.4.2. Considering the prominence mass (mp) is added at the last level mass.

(b) Base shear force (Fbp) for the mass (mp) is calculated using the equation (8.2):

= 2

(

(7) The maximum number of levels above embedding section (nniv) given in Table 8.9 can be

exceeded with a level, but not exceeding the height of P+4E for the seismic zones with ag0,15g,

if the following two conditions are fulfil:- Use masonry and mortar with which we obtain the characteristic compressive strength of

masonryfk 4,5N/sq.mm;

- Structural safety is verified by computing a nonlinear static procedure (biographical) as in

4.5.3.5.2.(8) In the same conditions as in (7) are accepted the decrease by not more than 20% of the minimum

wall density (p %) specified in Table 8.9, but without that it becomes less than 3 %.

(9) The provisions of (7) and (8) shall not apply to the structures with an overstrength factor as

defined in 8.3.4 (2) is set to u/1=1.0.(10) Providing the minimum constructive walls density in project (p%), as shown in tables 8.8 and

8.9 and/or a minimum characteristic strength of masonry from Tables 8.2 8.5 does not ensure

safety requirement in all cases of Architectural-Structural Composition of the building for allseismic zones, and therefore does not remove the obligation of the designer to check the calculationof this requirement.

8.3.3. Geometric and structural regularity and irregularity(1) The specific geometric and structural regularity criteria in plan and elevation for buildings with

structural walls of masonry used for seismic design situation is identical to that used for persistent

design situation and transient design situation detailed in the Code CR 6 and are in accordancewith the provisions of Chapter 4 of this P100/1-2013.

8.3.4. Behavioral factors

(1) The behavior factors "q" for masonry walls structures will be taken from Table 8.10.


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Table 8.10. The behavior factors "q" for masonry walls buildings

Regularity The behavior factors "q" for masonry walls buildings for:

Plan Elevation ZNA ZC ZC+AR ZIA

Yes Yes1.75u/1 2.25u/1 2.50u/1 2.75u/1

No YesYes No

1.50u/1 2.00u/1 2.25u/1 2.50u/1No No

1. For the one level structuresthe q values from this table are reduced by 15%.2. For ZC+AR structures the q values from this table are used only if in all the walls which

contribute to seismic force taking like in art. 8.3.2.2(3) the horizontal reinforcement from

the bed joints satisfy the requirement form P100/1-2013. If all these requirements arenot satisfied than the ZC values are used.

(2) The overstrength factor is defined by the expression u/1, in which:

- u represents 90% of the horizontal seismic force that, if the effects of other actions remain

constant, the structure reaches the maximum lateral capable force;- 1 represents the horizontal seismic force which, if the effects of other actions remain constant,

the first structural element reaches ultimate strength value (for bending with axial force or shear).(3) Calculation of overstrength factor can be done using any method of static nonlinear analysis.

Values u/1obtained by calculation shall not exceed by more than 25% of the standard valuesgiven in (4).

(4) If there is not a non-linear static calculation according to (3) for buildings with nniv 2, where

the masonry constitutive law with specific strains mu/ml>>1.0, values u/1 shall be taken as

follows:

- Buildings with unreinforced masonry structures (ZNA): u/1=1.10

- Buildings with reinforced masonry (ZC, ZC+AR, ZIA): u u/1=1.25

(5) Masonry structures with linear constitutive law with mu/ml1.0 for all types of burnt claymasonry and AAC, behavior factors q are taken as follows:

- Unreinforced masonry (ZNA): q = 1.50

- Confined masonry (ZC) and confined masonry and reinforced in the horizontal bed joints(ZC+AR): q = 2.0.

8.4. Seismic calculation of masonry buildings(1) Seismic computation for masonry buildings with structural walls will follow the principles and

general rules of P100/1-2013, par. 4.5 with specific data indicating in the followings.

(2) The elastic response spectra will be calculated using the equation (A.7.1.) of the P100/1-2013

Code. Correction factor given by equation (A.7.2) will take = 0.88, corresponding to the fraction

of critical damping = 8%.


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8.4.1. Terms of service

(1) The structural analysis model must adequately represent the stiffness properties of the entire

structural system.(2) Determination of sectional efforts (N, M, V) in structural walls and determination of lateral

displacements of the structure can be done by manual calculation procedures or by any computer

program based on recognized principles of structural mechanics.(3) The elastic stiffness of elements is calculated considering flexural and shear deformations ofthe non-cracked masonry.

(4) The most accurate results are obtained using masonry cracked stiffness.

(a) the unreinforced masonry walls (ZNA):(i) geometrical characteristics of non-cracked section masonry;

(ii) of the value of secant modulus of masonry short term (E z) with the value

calculated according to the characteristic strengthfk;

(iii) of the value of transverse modulus (Gz);(b) confined masonry (ZC) and reinforced core masonry (ZIA):

(i) the geometric characteristics of the whole non-cracked section (masonry and

concrete)(ii) of the value of elastic modulus equivalent of short duration (EZC (ZIA));

(iii) of the amount equivalent transverse modulus (GZC (ZIA)).

(5) The reinforced concrete coupling beams (spandrels) stiffness will take into account the valuesused for calculation of buildings with reinforced concrete structural walls (see CR2 -1 -1).

(6) Calculation model for unreinforced masonry walls with openings shall not take into account

the effect of coupling beams (spandrels). They will be armed so constructive that spandrels failureto precede the piers failure by local crushing of masonry.

(7) For the seismic design the slabs of the masonry buildings are classified in terms of horizontal

stiffness to:

- Rigid horizontal slabs;- Slab with insignificant horizontal stiffness.

(8) For the current buildings with masonry walls, the calculation model can consider the slabswithout further checks as rigid horizontal diaphragms if the voids not significantly weak them,

without verification by calculation the slabs which have the following composition:

- Monolithic reinforced concrete slabs or continue to RC continuous toping monolith precastslab with thickness 60 mm, reinforced with a steel mesh with area 250 sq. mm/m in

each direction;

- Slabs made of precast RC panels or semi-panels perimetraly combined with steel welded

loops and cast in place concrete;

- Slabs made of prefabricated "strips" with loops or connecting bars at the extremities andwith a continue RC topping thickness 60 mm, reinforced with a steel mesh with area

250 sq. mm/m in each direction (58/m).

(9) The slab that does not fully satisfy the provisions of (8) can be considered rigid in the horizontalplan if, when modeled with its real flexibility in the plan, the calculated horizontal displacements

for the seismic design situation do not exceed anywhere with more than 10 % the corresponding

absolute horizontal displacement.


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8.5.2.1.3. Sections of masonry weakened by gaps and slits.(1) The provisions apply to common persistent design situation and transient design situation given

in the Code CR 6, regardless of seismic zone, the building height and materials of masonry made.

8.5.2.2. Slabs

(1) To design the slabs will take into account the common provisions for persistent design situationand transient design situation, the general conditions given in P100/1-2013, art.4.4.4, and any

specific provisions from below.

(2) The slabs with insignificant horizontal stiffness are permitted only for:

- Top slab of buildings with walls masonry with a single level with or without attic - (P)or (P+M), for seismic zones with ag=0.10g;

- Intermediate slabs of buildings with two and three levels (P+1E 2E) important classes

III and IV in seismic zones with ag0,15g (excepting the slab above the basement);(3) For the case of slabs with large voids will observe the general conditions given in 4.4.4.5 and

the provisions of (4) and (5).

(4) The large voids positions will be set that does not reduced the stiffness and strength of the slabs

and ensure the transfer of the horizontal forces to the structural walls without major concentration

of efforts. To this aim, must avoid positioning the openings at the corners of the slabs, near thecontour walls or joining several neigbour openings.

Figure 8.2. Placing large openings in slabs

(5) In cases where the significant weakening of the slabs through goals can not be avoided willtake into account the effect of finite stiffness of the slab by adopting a computational 3D model.

8.5.3. The infrastructure design(1) The establishment of infrastructure for buildings with masonry walls shall comply with the

general provisions for persistent design situation and transient design situation, the generalprinciples and specific provisions 4.4.1.7 data given below.

(2) Sizing foundations, sockets and basement walls will be made by calculation to satisfy the

strength conditions for the effects resulting from the fundamental loading group. Dimensions thusobtained will be checked for the effects of seismic loading group.


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(3) In seismic zones with ag0.25g, sizing foundations, plinth and basement walls, seismic action

effects are taken into account by the design strength values for bending with axial force in the

elevation of the wall determined considering the reinforcement strength increased with 25 %. Inthe coupled walls case will take into account also the axial force changing corresponding to shear

strength of the coupling beams (spandrels) design (indirect axial forces).

8.5.3.1. Structural walls foundations(1) The walls masonry foundations will be continue flange.

(2) As an exception to (1) in areas with seismic design acceleration ag0.15g in the case of low

vertical load (buildingsP+1E+M) for buildings of importance classes III and IV, normalfoundation soil with conventional pressure pconv> 200 kPa, can provide even isolated foundations

with plain concrete, connected with reinforced concrete beams in both directions.

8.5.3.2. Sockets

(1) If no basement constructions, the sockets and foundations shall be made of reinforced concrete,except mentioned in (2).

(2) In land locations with normal foundation soils for building importance class III, nniv 3, in

seismic areas with ag0.15g and construction of importance class IV in all seismic zones, thesocket can be made of plain concrete when the computation results under the loads mentioned in

8.5.3. (2) allows the solution.

8.5.3.3. Basement walls(1) The basement walls of buildings with masonry structural walls will be made of reinforced

concrete except as provided in (2).

(2) In land locations with normal foundation soils for building importance class III, nniv3, inseismic areas with ag0.15gand construction of importance class IV in all seismic zones, basement

walls can be made of plain concrete when the computation results under the loads mentioned in

8.5.3. (2) allows the solution.

(3) In the seismic zones with ag0.25g will avoid significant weakening of the basement walls byopenings, areas with low strength will be verified by calculation and, if necessary, adopt solutions

to enhance their strength.

(4) For the buildings with masonry wall disposed in cellular system, in seismic areas withag0.25g, except to the extent of (3) is recommended to increase the rigidity of the basement walls

by introducing additional walls (dense walls basement system).

8.5.3.4. Infrastructure slabs(1) The slab above the basement will be from reinforced concrete regardless of the seismic zone,

the building height and materials of masonry made.


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8.5.4. Specific design rules for building made of masonry structural walls(1) For the design of structural walls and slabs shall meet the general rules in Section 8.5.2. and

specific rules given below.(2) It is recommended that the in plane dimensions of full masonry zones, between openings or to

the edges of the wall to be a multiple of the length of masonry elements.

(3) The condition from (2) is mandatory for masonry made of burnt clay elements from Group 2B,in this case, to eliminate the cutting/breaking of the elements onto the site, only special elementswith equal length with submultiple of a nominal length of those varieties can use. If modulation is

not performed will increase the size of the RC column belts (ties).

(4) In the case of masonries with the reference height of the row 200 mm the masonry panelheight, in-between the reinforced concrete beam belts (ties) will be a multiple of the row height

(element height plus the thickness of the mortar about 10 12 mm).

Figure 8.3. Masonry modulation concerning the size of the masonry elements

(5) In case of buildings with slabs made of linear elements (which discharge in one direction) in

all seismic zones and irrespective of masonry type (ZNA, ZC or ZIA) will provide constructivemeasures to anchor at each slab, of the exterior structural walls disposed parallel to the main

elements of the slab.

It is recommended that all structural walls be loaded directly on the contour of the floor.

8.5.4.2. Specific rules for buildings with unreinforced masonry structural walls (ZNA)

(1) All buildings with unreinforced masonry structural walls, regardless of masonry elements and

mortars used will have RC column belts (ties) with a constructive disposal, according to seismiczone in concordance with 8.5.4.2.1. (1).

(2) Over e door and window openings will provide RC lintels connected, usually with beam belts

(ties) from the slab.(3) For buildings located in seismic zones with ag0.15g in the connection areas between

perpendicular walls (corners, bends and junctions) will provide reinforcement in horizontal joints

in accordance with 8.5.4.2.4.


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8.5.4.3. Specific rules for buildings with confined masonry structural walls (ZC)(1) In the buildings with masonry walls, regardless of masonry elements and mortar used will be

provided vertical RC column belts (ties) and horizontal beam belts (ties) with a disposal as follows:(a) For buildings made with ZNA - items with constructive role;

(b) For buildings made with ZC and ZC+AR - elements with structural role.

(2) The plane and vertical positions and the sizes of cross-section and longitudinal and transversereinforcement for column belts (ties) and beam belts (ties) shall be determined taking into accountthe effects of vertical load and seismic design forces under the conditions specified below.

8.5.4.3.1. Column belts (ties) requirements(1) In all buildings with simple masonry walls (ZNA) with elements of burnt clay bricks and AAC,

it will provide as a constructive measure, RC column belts (ties) in the following position (Figure

8.4 a):

(a) For ag0.15gseismic areas at all outside corners and entering corners of the buildingoutline (SC1)

(b) For seismic zones 0.15g


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8.5.4.3.2. RC beam belts (ties) requirements(1) For all buildings, regardless of the composition of masonry (ZNA, ZC or ZIA) and the seismic

area the RC beam belts (ties) will provide in the walls plane:(a) on each floor slab, regardless of the material it is made (RC or wood) and its production

technology;

(b) the intermediate position, for the multistorey buildings with rare-walled structuralsystem (cellular system) and construction type "audience hall/warehouse" whose structuralwalls have height > 3.20 m, in seismic areas with ag0.15 g, or > 4.00 min seismic zones

with ag=0.10g.

(2) If the attic or uncirculated loft buildings with wood roofs will provide all belts at the top ofexceeding the last slab walls.

(3) The belts provided under (1) shall be continuous for the entire length of the wall and will form

closed contours. The RC beam belts (ties) from the current and the roof levels will not be

interrupted by doors and windows openings except as provided in (4).(4) The RC beam belts (ties) continuity can be interrupted only in the following situations:

(a) The RC beam belts (ties) for the current floor in the stairwell right, subject to assure:

(i) RC column belts (ties) on both sides of the opening;(ii) A RC beam belts (ties) - lintel at intermediate walkways linked to the two RC

column belts (ties) from both sides of the opening;

(b) The RC beam belts (ties) over the attic walls near the dormers, subject to assure:

(i) RC column belts (ties) on both sides of the opening, with longitudinalreinforcement properly anchored in the RC beam belts (ties) from the below level;

(ii) RC beam belts (ties) over masonry parapet above the window, tied to two RC

column belts (ties) on both sides of the opening.

Figure 8.5. Interrupting the staircase RC beam belts (ties)

(5) It is recommended that the staircase RC beam belt (tie) interruption, to be fitted for buildingsin seismic zones with ag 0.20g.(6) The cross section of RC beam belts (ties) will meet the following conditions:

(a) Cross-sectional area 500cm2 with the following dimensions:

(i) the width 25 cm, but 2/3 of the thickness ;(ii) The height than floor slab thickness for interior walls and than double that

than floor slab thickness for the walls on the perimeter of the building and the

staircase.


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(7) The RC beam belts (ties) reinforcement is established by computation with the following

minimum conditions:

(a) the percentage of longitudinal reinforcement:(i) 1.0 % for the seismic zones with ag0.25g;

(ii) 0.8% for seismic zoneswith ag=0.15g and ag=0.20g.

(iii) 0.6% for seismic zones with ag=0.10g.(b) longitudinal bars diameter 12mm;(c) transverse reinforcement:

(i) closed stirrups with 6mm;(ii) the distance between stirrups: 15 cm in the current field and 10 cm in length

of longitudinal bars overlapping and 60 cm at intersections with RC column belts(ties).

(8) The splice of the longitudinal bars in RC beam belts (ties) shall be made by overlapping,

without hooks, on a length 60. Spliced sections of the bars must be staggered by at least 1.00

m in a section will be spliced bars more than 50 % of the RC beam belt (tie).

Figure 8.6. The overlapping of the bars in RC beam belts (ties)

(9) In corners, junctions and bends it will assure a monolith link of the RC beam belts (ties)

disposed on the two directions and the continuity of efforts transmission will be made by anchoring

the longitudinal bars into perpendicular RC beam belts (ties) by a length 60

(10) If vertical slits case made by building, the RC beam belts (ties) reinforcement continuity that

are interrupted will be made by additional bars provided with a section at least 20% higher thanthe interrupted ones.

Figure 8.7. Reinforcement for RC beam belts (ties) weaker by slits

(11) In the case of buildings with wooden roof in the RC beam belts (ties) from the top level willprovide specific steel pieces for anchoring the purlins from the roof structure.

8.5.4.3.3. Provisions for lintels and coupling beams (spandrels)

(1) For the current buildings, the coupling beams (spandrels) must be monolithic bounded with the

RC beam belts (ties) of the slab.


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(b) The mortar side coverage for the bars in joints (beds) shall be established to ensure

corrosion protection for the bars.

Figure 8.8. Masonry wall reinforcement at intersections

(4) The reinforcements from the horizontal joints/beds are anchored in the RC column belt (tie) orextended in masonry piers beyond the edge of the opposite RC column belt (tie) to achieve a total

anchorage length of at least 60. The bars will be trimming without hooks.

(5) The bars splice in joints/beds shall be made by overlapping, without hooks, by a length of

60. Spliced sections of the bars must be staggered by at least 1.00m; in one section will bespliced no more than to 1/3 of the wall bars.

8.5.4.4. Specific design rules for building with reinforced core masonry (ZIA).(1) The brick walls of marginal layers will have a thickness of bricks (115mm minimum) will

be made with woven masonry and vertical joints shall be completely filled with mortar. Do not

accept used items with mechanical joints (T & G) for the two layers of brickwork of ZIA.(2) The median thickness of concrete or mortar-concrete (grout) shall be 10cm.

(3) The median reinforcement layer will be determined by computing.

(4) For the first level of buildings with nniv3, the minimum reinforcement ratios, relative to the

median layer of concrete section, shall meet the requirements of Table 8.12. The minimum

diameter of the bars will be 8mm and distance between bars shall be 150mm.

Table 8.12.Minimum reinforcement ratio for walls ZIA

Seismic design

acceleration ag

Horizontal reinforcement bars Vertical reinforcement bars

1stcategory 2ndcategory 1stcategory 2ndcategory

ag0.20g 0.30% 0.25% 0.25% 0.20%

ag0.15g 0.25% 0.20% 0.20% 0.15%

(5) For the buildings of nniv

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