contribution to the adoption of ready … · in the design of structural masonry buildings grabarz,...

15th International Brick and Block

Masonry Conference

Florianópolis – Brazil – 2012

CONTRIBUTION TO THE ADOPTION OF READY WOODEN DOORS

IN THE DESIGN OF STRUCTURAL MASONRY BUILDINGS

Grabarz, Regina Candeloro1; Parsekian, Guilherme Aris

2

1 MSc Candidate, Federal University of São Carlos, Civil Construction Graduated Program, [email protected]

2 PhD, Professor, Federal University of São Carlos, Civil Engineering Department, [email protected]

In Brazil, the construction industry has experienced moments of great development in recent

years, reflecting high demand for products in this booming market, indicating a need for

increase productivity and reduces waste of physical and financial resources, through the

adoption of techniques and systems that seek to industrialization and rationalization of

building. Recently published the Brazilian Code NBR 15873:2010, modular coordination

standard for buildings, represent a great influence on the development of all sectors of

construction towards industrialization and rationalization, especially when united with the

structural masonry construction system. This research proposes a study aiming to contribute

to the use of modular coordination in the design of structural masonry, by investigating the

dimensional standards appropriate to the element wood door. With this information we to

intend diagnose and analyze the dimensional standard of wood door sold in Brazil, in order to

verify their application in design of structural masonry making use of modular coordination.

Comparing the Brazilian standard dimensions with the suggested by the research for structural

masonry, there was a significant difference, in height 25 mm and in width 30 mm,

invalidating the dimensional proposal of the Brazilian standard, NBR 15930-2:2011 (wooden

ready doors), to fit in structural masonry buildings. Pointing to the adoption of measures not

rationalized as the need to fill the gaps with adjacent materials and to provide service and

ahead of time for such work.

Keywords: Structural Masonry, Ready Wooden Doors, Modular Coordination

Theme: Solutions for Developing Countries - low cost masonry buildings

INTRODUCTION

The construction industry has experienced moments of great development in recent years due

to factors of great impact as the 2014 World Cup, the Olympics in 2016, the Growth

Acceleration Program (Programa de Aceleração do Crescimento - PAC), the Program My

Home My Life (Programa Minha Casa Minha Vida - PMCMV), and the expansion of

mortgage lending, reflecting high demand for products in his booming country. Foreign

investors turned their eyes to this promising market, contributing to the competition becoming

even fiercer.

Companies in the industry, builders, developers, among others, to fulfil the needs at this

moment are adopting survival strategies based primarily on meeting customer needs,

presenting a quality product at an affordable cost. With all of that the enterprise return (profit)

is mainly linked to increased productivity and reduced physical and financial resources waste,


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through the organization of the technologies and building systems, leading to the adoption of

techniques and systems that seek to industrialization and rationalization of building.

The national construction industry is no longer accepting waste and improvisations. Those

traditional buildings, often amateurishly managed, where the definitions of the interfaces

between the various systems and building components were forged at the time of execution,

are no longer appropriate. Instead, the speed of construction and the high level of organization

of the construction site link to integrated solutions. In other words, there is a strong demand

for the industrialization of construction, referring to both the industrialization of the

components and elements (materials) and industrialization of the construction site (methods).

In this environment, modular coordination is a key factor and presents itself as an excellent

strategic tool since this is intended to "organize the dimensions of buildings, in order to

reduce the variety of sizes in which all components and equipment must be produced, and

allow its use in the bed without modifications, cuts or touches" (BRUNA, 1976).

In the widely locally structural masonry buildings, the modular coordination is supposed to be

naturally solved by the right distribution of the standards blocks. However, although this

system has indeed contributed to the rationalization of the building industry in Brazil, not all

components in the market do meet coordinated dimensions, in which the wood-made doors

are a bold example. Considering the installed dimensions the standard door height is multiple

of 200-mm. Prior to the door installation a reinforced concrete precast lintel, in which central

height is greater than at supports, must be installed rather than simply using bond-beam

blocks.

The reason for that comes from long time ago, when the construction standard was based on

brick dimensions. Why those dimensions are still an industry standard is the question of this

paper. Therefore, this article seeks to contribute to the use of modular coordination in the

design of structural masonry, by investigating the dimensional standards appropriate to the

element wooden door.

METHODOLOGY

The simplified methodology steps were:

Analyze the possible dimensions for doorways in the structural masonry;

Diagnose and analyze the possible finishing elements that may influence the size of

the doorway;

Define the appropriate dimensional standards (according to the parameters in this

study) to ready-installed wooden doors;

Diagnose the dimensional standards of ready-installed wooden doors marketed in

Brazil; and

Analyze comparatively the dimensional standards suggested in the research and

marketed in Brazil.


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MODULAR COORDINATION CONCEPTS

Seeking to understand the meaning of modular coordination was defendant the definition of

NBR 15873:2010 which says that it is "dimensional coordination employing the basic module

or multimodule”. This definition is not clear when you do not understand the meaning of

dimensional coordination, basic module and multimodule. To understand what is modular

coordination it is first necessary to understand the concepts it covers.

The word coordinate, refers, according to Ferreira (2004), to “dispose elements in a certain

order and method, organize and/or guide, connect coherently”. Bringing this definition to the

civil construction we can say that it's the concern to unite and organize in a coherent way, the

construction elements and components of a building.

When the method to organize in a coherent union is dimensional, through measures, then you

have the dimensional coordination. Since the unit of measurement used for the dimension

coordination is represented by the basic module this becomes MODULAR

COORDINATION. Therefore modular coordination in the civil construction is the union of

the construction elements and components of a building following an organized and coherent

method, based on modulation.

The space required to install each element or component (coordination space) includes not

only its own dimension (nominal dimension), but also the gaps needed for tolerances

(manufacturing, marking and installation) and joining materials when appropriate

(coordination adjustment). For further information Table 1 contains the definitions relevant to

this study according to NBR 15873:2010.

Table 1: Relevant concepts to research on modular coordination (NBR 15873:2010) CONCEPTS DEFINITIONS

Nominal Size Measure expected of an object before execution/fabrication

Real size Measured verified directly in the single object after its execution/fabrication

Tolerances Allowable difference between the real size and corresponding nominal size

Coordination

space

Space required for a constructive element or component, including deformations and

clearances for installation tolerances and union material, if applicable

Coordination

adjustment

Difference between the real size and corresponding nominal size. The coordination

adjustment provides space for deformation, tolerances and material union, if applicable

Modular

coordination Dimensional coordination employing the basic module or multimodule

Dimensional

coordination

A convention on related sizes for the coordinating dimensions of building components and

the buildings incorporating them, for their design, manufacture and assembly.

Basic module Smallest unit of linear measurement of modular coordination, represented by the letter M,

whose normalized value in Brazil is M = 100 mm

Multimodules Integer multiple of the basic module

Sub-modular

increment

Fractions of the basic module, with the following standard values: M/2 = 50 mm; M/4 = 25

mm; M/5 = 20 mm.

Modular

reference

system

Geometric system of n dimensional orthogonal planes, in which the distance between any

two parallel planes is equal to the basic module or a multimodule

Component

(constructive)

Distinct unit of a particular element of the building with definite form, with the measures specified in three dimensions and designed to meet specific functions. Examples: Block

masonry, tile, and other pane

Element

(constructive)

Part of the building with specific functions, consisting of a component or set of components

and/or building materials. Example: wall, window, door, stairs, and other


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BRAZILIAN READY DOOR STANDARD

In Brazil, the NBR 15930-2:2011 establishes the requirements for ready doors (kit), set the

dimensional standards and tolerances for these products, always working with reference to the

leaf dimension, as can be seen in Table 2, where was adapted values from Tables 1, 2, 4 and

5. Knowing that for this study was considered doors with average mass (10 to 20 kg/m²) and

one leaf.

Table 2: Standardized measure for door with average mass (10 to 20 kg/m²) (NBR

15930-2:2011)

DOOR LEAF (mm)

Dimension and tolerance for the

door set (kit)


clearance in masonry when fixed

with polyurethane foam

(H + 33) / (W + 55) (H + 45) / (L + 80) / (±10 tolerance)

Height (H) 2100 2133 2145

Width (W)

(*) just for

internal doors

600* 655 680

700* 755 780

800 855 880

900 955 980

1000 1055 1080

1100 1155 1180

DIMENSIONAL STUDY OF MASONRY: BLOCK AND DOORWAY

The structural masonry is designed by dimensional or modular coordination (basic module M

= 100 mm). Performed based on coordination space of structural block, formed by the

nominal dimension of the structural block added to the coordination adjustment (see Table 1).

In the case of structural block we should add 5 mm of mortar 5 mm direction of the block,

resulting in an increase of 10 mm to nominal dimension, as illustrated in Figure 1. Taking as

example the structural block of nominal size 140 x 190 x 390 mm (width, height and length),

resulting in a coordination space (coordinate dimension) of 150 x 200 x 400 mm and a

modular coordination space (modular dimension) of 1.5 M or 3/2 M x 2M x 4M.

Figure 1: Modular Coordination of a Structural Block; Nominal Dimension (mm),

Coordinate Dimension (mm), Modular Dimension (M = 100 mm), Coordination Space

(cm) and Coordination Adjustment (cm)


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The most common masonry units in Brazil are concrete or clay hollow blocks, then they are

the object of this research. Different dimensional families of blocks are sold, with the half-

length of the standard block of each family plan the modular coordinate dimension. In lengths

two different nominal blocks are available, 300 mm (3M) and 400 mm (4M). In height the

blocks do not exhibit variations in size remained at 200 mm (2M).

The block thickness range from 100 mm (1M), 125 mm (1.25 or 5/4M), 150 mm (1.5 or

3/2M) and 200 mm (2M), also for both materials. The most used in Brazil, are the width of

150 mm (1.5 or 3/2M), with some cases of using 200 mm (2M).

In this paper the modulations 1.5 x 3M and 1.5 x 4M in plan and 2M in height is assessed as

for being the main case in Brazil. The width (1.5 M) has little influence in this study, which

aims to analyze the possible door spaces, mainly influenced by the height and the length of

the standard block (main).

When analyzing the elevation of masonry, on a 200 mm horizontal modular reference grid,

according to Figure 2, there is the possibility of multiple spans of 200 mm. In Brazil clearance

for doors must have a height greater or equal to 2100 mm, resulting, in height, in a modular

doorway with 22M, or 2200 mm (coordinate dimension). It can be seen, in Figure 2, that in

height, was added 10 mm in coordinate dimension, being 2210 mm (nominal dimension),

arising from the rendering of 5 mm from the bottom of the channel block (lintel) and 5 mm

mortar that would be present between the first row of blocks and the floor.

Figure 2: Height of the doorway in structural masonry

Detailed studies were made with the possible doorways horizontal sizes considering the 1.5 x

3M (150 x 300 mm) and 1.5 x 4M (150 x 400 mm) block-family. Diagnosing the possibility

of creating doorway multiples of 50 mm (710, 760, 810, 860 mm, and so on). Based on the

basic module (100 mm), it is understood as being the ideal modular masonry openings for

doors, the wide of 7M, 8M, 9M, 10M and so on, all multiples of the basic module (100 mm).


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Figure 3 illustrates the concepts of modular coordination to the width of the doorway, taking

as an example doorway 8M. It can be seen, in the Figure 3 that in width is also found that

there is a difference of 10 mm between the extent of coordination and nominal dimension

(810 mm), referring to the discount of 5 mm plaster on both blocks that limit the range,

considered the extent of coordination of the block.

Figure 3: Example of modular coordination and its concepts applied to doorways in the

design of structural masonry

WOODEN DOORS

The constructive element door is composed by the door-post (fixed part aimed at trimming the

gap and support the door leaf), the door leaf (main moving part of a door), the frame (used to

cover the joint between the wall and the door-post) and the ironmongery (arrangements for

the proper operation of the door, generally formed by all the hinges and the lock). Being the

most often used type of door the open door with one leaf, so the object of this study, as shown

in Figure 4.

Figure 4: Model of door studied and its components


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Following the principles of modular coordination, according to NBR 5728, the door element,

including the entire whole, is modular considered when designed and produced to fill a

modular range. So the real measure of the ready door must fill the modular doorway in the

masonry, having this 2210 mm (22M), as shown in Figure 2.

With a focus on industrialization and rationalization of structural masonry construction,

currently a good solution for wooden doors, it is the ready-door kit or just ready door, being

the door (door-post, leaf and ironmongery) supplied factory-fitted (comes with frame,

however assembled on site).

According to manufacturers, the ready door must be installed during the building finishing

stage, when renderings (wall and floor), sills, roofs, ceilings and painting are completed. Thus

the finishing elements that influence the dimensional coordination of the ready door are the

regularization mortar applied to the slab, the ceramic tile adhesive mortar and ceramic tile.

Since masonry is built from the plane of the slab, so the set described above will influence

dimensionally in the masonry free space designed to the installation of the door (doorway).

For the floor regularization it is adopted a thickness of 30 mm, considering Barros and

Sabbatini (1991) recommendations, which can be made through projects and execution

control.

For the tile adhesive mortar it is adopted a thickness of 3 mm, minimum recommended by

manufacturers of this material (maximum of 4 mm). For ceramic tile was adopted the

thickness of 7 mm, whereas in Brazil the thickness of ceramic floor tile marketed generally

range between 6,3 and 7,4 mm. Summing this all a gap nominal size of 40 mm above the

floor (slab) is obtained.

DIMENSION STUDY OF READY DOORS FOR STRUCTURAL MASONRY

Following the parameters described by the standard of wooden doors, NBR 15930-2:2011,

and knowing the clearance of structural masonry, was possible to obtain the ideal dimensions

for ready doors in structural masonry designs (according to the parameters described above).

In height, starting from the coordinate dimension of masonry clearance 2210 mm, in which

discounting 40 mm for the set floor space, remains 2170 mm of free space in masonry.

Discounting 45 mm, considered difference between the size of the leaf and the clearance in

masonry (Table 2), it can have the size of the ideal leaf, 2125 mm, as shown by Figure 4 and

Equation 1. With adding 33 mm can have the dimension of the door set (kit), been 2158 mm.

(1)

In width, starting from the coordinate dimension of masonry clearance using, as an example,

810 mm, in which discounting 80 mm (Table 2) it can discover the dimension for the leaf,

730 mm, as shown by Figure 4 and Equation 2. Which adding 55 mm result the size of the

door set (kit), been 785 mm. Allowing fill the Table 3.

(2)


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Table 3: Ideal dimensions for ready wooden doors (with average mass 10 to 20 kg/m²)

DOOR LEAF (mm)

H and W


door set (kit)


clearance in masonry when fixed

with polyurethane foam

(H + 33) / (W + 55) (H + 45) / (L + 80) / (±10 tolerance)

Height (H) 2125 2158 2170

Width (W)

(*) just for

internal doors

630* 675 710

730* 785 810

830 885 910

930 985 1010

1030 1085 1110

1130 1185 1210

Figure 4: Doorway and wooden ready door dimensions

INTERVIEWS AND FIELD STUDY

Interviews were conducted with the largest ready door manufacturers, in Brazil, questioning

the possibility of producing kits with specific measures, the possible impact on the price and

minimum quantity required.

Some do not accept orders outside of the standard measures produced by them, in any manner

requiring minimum purchase of 100 units. Two of the manufacturers accept custom orders but

with increased costs ranging from 20% to 60% and with a minimum purchase of 100 units in

all cases.

Although outside the standard, some producers manufacture doors with width of 620, 720,

820 and 920 mm. In height, were not diagnosed variations, keeping with 2100 mm.


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ANALYSIS OF RESULTS AND CONCLUSIONS

Comparing the Brazilian standard dimensions with the suggested by the research for structural

masonry, as reported in Table 4, there was a significant difference, in height 25 mm and in

width 30 mm.

Table 4: Ideal dimensions for ready wooden doors (with average mass 10 to 20 kg/m²)

DOOR LEAF (mm)

H and W

Dimension and tolerance for the clearance

in masonry when fixed with polyurethane

foam

Suggested Brazilian

standard Difference Suggested

Brazilian

standard Difference

Height (H) 2125 2100 25 2170 2145 25

Width (W)

(*) just for

internal

doors

630* 600*

30

710 680

30

730* 700* 810 780

830 800 910 880

930 900 1010 980

1030 1000 1110 1080

1130 1100 1210 1180

In fact it is a conclusion based on what everyone who works with structural masonry knows,

that the clearance in the structural masonry usually follows the pattern of, in width, 710, 810,

910, 1010, 1110 and 1210 mm, or, 760, 860, 960, 1060, 1160 and 1260, and in height 2210

mm. So how can be propose by the standard that the masonry clearance has, in width 680,

780, 980, 1080 and 1180 mm, and in height 2145 mm?

This invalidates the dimensional proposal of the Brazilian standard, NBR 15930-2:2011

(wooden ready doors), to fit in structural masonry buildings and points to the adoption of

measures not rationalized as the need to fill the gaps with adjacent materials and to provide

service and ahead of time for such work.

REFERENCES

BARROS, M. M. S. B. de; SABBATINI, F. H. Tecnologia de produção de contrapisos

para edifícios habitacionais e comerciais. São Paulo: EPUSP, 1991.

BRUNA, P. J. V. Arquitetura, industrialização e desenvolvimento. São Paulo: Perspectiva,

1976. 307 p.

FERREIRA, A. B. de H. Miniaurélio: minidicionário da língua portuguesa. 6 ed. Curitiba:

Positivo, 2004. 896 p.

ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS (ABNT). NBR 5728: detalhes

modulares de esquadrias: procedimento. Rio de Janeiro, 1982

ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS (ABNT). NBR 15873:

coordenação modular para edificações. Rio de Janeiro, 2010.

ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS (ABNT). NBR 15930-2: portas de

madeira para edificações: parte 2: requisitos. Rio de Janeiro, 2011.

contribution to the adoption of ready … · in the design of structural masonry buildings grabarz,...

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