Brick Nomogram

LITERATURE REVIEW ON COMPARINGCLAY BRICKS NOMOGRAMS WITH FLY-

ASH BRICKS Dhaval M. Vaviya* * (PG-Construction Engineering & Management student), B.V.M. Engineering college, Gujarat

Technological University, Vallabh Vidhayanagar, India.

Email ID:*[email protected]

Prof.J.J.Bhavsar#Professor, Civil Engg Dept, B.V.M.Engineering

College,

V.V.NagarEmail: [email protected]

Jayesh Pitroda## Asst.Professor & Research Scholar in civil

engineering department, B.V.M. Engineering College, Gujarat Technological University, Vallabh

Vidhayanagar, India. Email ID:#[email protected]

ABSTRACT-Fly-ash bricks are well known bricks. Fly-ash bricks are slow but surely replacing conventional clay bricks for wall constructions. It is green and environment friendly material. For achievement of real sustainable development. In this present study we are using clay bricks nomograms which is given in national building code SP: 10-1975 for finding out external and internal wall thickness. For that they are using clay bricks and different types of mortar for finding out basic stress. Instead of clay-bricks we are using fly-ash bricks and different types ofmortar for finding basic stress.

KEYWORD:Nomograms, Clay Bricks, Fly-Ash Bricks,

INTRODUCTION

A nomogram, nomograph, is a graphical calculating device, a two-dimensional diagram designed to allow the approximate graphical computation of a function: it uses a coordinate system other than Cartesian coordinates.

Defining alternatively, a nomogram does a (two-dimensionally) plotted function with n parameters, from which, know n-1 parameters, the unknown one can be read, or fixing some parameters, the relationship between the unfixed ones can be studied. Like aslide rule,

it is a graphical analog computation device; and, like the slide rule, its accuracy is limited by the precision with which physical markings can be drawn, reproduced, viewed, and aligned.

Most nomograms are used in applications where an approximate answer is appropriate and useful. Otherwise, the nomogram may be used to check an answer obtained from an exact calculation method.(2)

Structural Design Of WallsBritish Code CP.lll divides the walls into two

categories:

1. non-calculated walls 2. Calculated walls.

Non-calculated walls are those which are used as thin panel walls in framed structures and which do not carry roof load. The design of such wall is based on certain rules and not on the basis of calculations.

On the other hand calculated walls are the load-bearing walls of high rise buildings, which support floor and roof, and the design of which is based on calculations and not on rules. The method of design of such walls is commonly known as calculated masonry method the calculated masonry method can be applied in two ways:(5)

1. Design by use of nomograms. 2. Design by structural analysis.

TABLE 1.1 BASIC COMPRESSIVE STRESS (Fb) FOR MOSONRY MEMBERS* Note 1. A,B,Care types of Lime conforming to relevant

Indian Standards.* Note 2. Inclusion of lime in cement motors is optional.

13-14 May 2011 B.V.M. Engineering College, V.V.Nagar,Gujarat,India

National Conference on Recent Trends in Engineering & Technology

* Note 3. The above table is valid for slenderness ratio upto 6.

* Note 4. Symbols H,M,L denote high strength, medium strength and low strength motors. (10 kg / cm2- 1 N /mm2 )

Design By Use Of Nomograms Results of structural analysis, based on 'calculated

masonry method', for certain loadings and span, have been presented in the form of nomograms, by the National Building Code of India (SP : 7-1970). Though the nomograms presented in the Cods cover buildings upto 6 storeys, it is viewed that there is risk of some portion of the structure getting overstressed, on account of unfavourable location and shape of openings and occurrence of concentrated loads thusendangering the structural safety of tall buildings It is desirable, therefore, to use the nomograms to design buildings upto 3 storey height Buildings exceeding 3 storeys in height should be designed by detailed structural analysis.

Figs. 1.1 and 1.2 give two typical nomograms for the design of walls of residential buildings, for class 200 loading with 2.8 m and 3.2 m storey heights respectively. For other cases of loadings and storey heights, reference may be made to the National Building Code of India ( SP : 7-1970).

The nomograms for determining thickness of brick wall contain nine vertical lines. From left to right, the vertical lines represent as follows :

Line 1: Basic stressLine 2: StoreysLine 3: Reference line 1Line 4: Span pointLine 5: Reference line 2Line 6: Percentage of openingLine 7: Thickness of wall for span of 3.0 mLine 8: Thickness of wall for span of 3.6 mLine 9: Thickness of wall for span of 4.2 m.(5)

Line 1: Basic stress. Basic stress for the type of masonry is taken from Table 1.1.

Line 2: Storeys.Though the nomograms can be used for buildings upto 6 storeys height, it is preferable to use it only upto 3 storey height. For use of nomograms in the case of multi-storeyed buildings, the all thickness at each floor is found by passing the line through the 'numberof storeys above that section.

Line 3: Reference line 1.This line fixes a point on the line for any combination of basic stress and storeys.

Line 4: Span point. The fourth line has a span point through which all lines shall pass through for arriving at the wall thickness.

Line 5:Reference line 2.This reference line also fixes a point on the line for any combination of values for basic stress and storeys.

Line 6: Percentage o f openings.This line takes care of openings provide on the

wall, for windows, doors, ventilators etc. For example, if a wall, 6 m long has a door of 1 m width and window of 1.5 m width, the gross horizontal area of wall, at a plane where there is no opening, will be 6 twm2, where twis the thickness ofwall in metres. The area of opening at the window level will be = (1 +1.5) tw=2.5 twm.

Hence the percentage opening = (2.5 tw /6tw)*100=41.7% nomograms are valid upto 50% openings.

Lines 7, 8, 9: Thickness o f wall.The last three lines give the thickness of wall for three spans of the rooms (i.e. 3.0 m, 3.6 m and 4.2 m). Thickness are indicated on both the sides of these lines. The bold markings on the left hand side of the lines give the thickness of the external walls and the dotted markings on the right side of the lines give the thickness for internal walls. Internal walls are analyzed as walls" having spans on either side. The numbers 1, 1.5, 2 etc. on these lines indicate the (number of ) brick thickness.

Fig 1.1 nomogram for wall thickness:Residential building : class 200 (live load) ,Dead load : 415kg/m2

Storey height : 2.8 m

Method of use of nomograms:The Method Of use of nomograms for determining

the thickness of brick wall has been illustrated in Figs. 1.1 and 1.2 by a dottedline. The following procedure may be adopted :

1. Choose the basic stress corresponding to the properties of masonry units and type of mortar to be used. For example, if we use bricks having crushing strength of 140 kg/cm2 (14N/mm2) and 1 : 1 : 6cement-lime mortar, the basic compressive stress,



found from Table 1.1, will be 11 kg/cm2 (1.1 N/mm2). This stress of 11 kg/cm2 is marked on the first line of the nomograms (Fig. 1.1.).

2. If the building has 4 storey’s, and the wall is to De designed at the ground level, the point of 11 kg/cm2

is joined to storey 4 of the second line (story line), and extended to cut reference line No. 1 at point A.

3. Join A to the span point and prolong further to cut the reference line No. 2 in point B

4. Suppose the percent openings in the wall are 50. Join the Point B to 50 mark on the 6th line (opening line), and extend it further to cut the thickness lines in C, D and E.

5. The thickness of wall shall be the v a l u e o f t h e d i v i d i n g l i n e w h i c h A p p e a r s .

Fig 1.2 nomogram for wall thickness:Residential building : class 200 (live load) ,Dead load : 415kg/m2

Storey height : 3.2 m

About the point of intersection on the thickness line. For example, in Fig 1.1, the points of intersection C, D, E represent the following thickness:

This nomogram is valid for the following conditions:i. Buildings ( residential ):

- Live loading … 200 kg/m2

- Dead loading (assumed) … 415 kg/m2

ii. Storey height … 2 . 8 mI A For residential buildings (class 200 loading) with 2.8 m storey height

This nomogram is valid for the following conditions:iii. Buildings ( residential ):


- Dead loading (assumed) … 415kg/m2

iv. Storey height … 3 . 2 mI B For residential buildings (class 200 loading) with 3.2 m storey height

points of intersection C, D, E represent the following thicknesses :

Thickness ((in Brick Thicknesses))

Point Span m

External Wall Internal wallC 3.0 1.5 1 . 5

D 3.6 1.5 1.5

E 4.2 1.5 2



This nomogram is valid for the following conditions:v. Buildings ( office ):



vi. Storey height … 3 . 0 mI C For office buildings (class 300 loading) with 3.0 m storey height

This nomogram is valid for the following conditions:vii. Buildings ( office ):



viii. Storey height … 3 . 2 mI D For residential buildings (class 300 loading) with 3.2 m storey height

This nomogram is valid for the following conditions:ix. Buildings ( office ):



x. Storey height … 3 . 8 mI E For office buildings (class 300 loading) with 3.8 m storey height

This nomogram is valid for the following conditions:xi. Buildings ( office ):



xii. Storey height … 3 . 0 mI F For office buildings (class 400 loading) with 3.0 m storey height (4)



CALCULATION OF BASIC COMPRESSIVE STRESS OF MASONRY

BY PRISM TEST

B-1. DETERMINATION OF COMPRESSIVE STRENGTH OF

MASONRY BY PRISM TEST

B-1.1 when compressive strength of masonry (f'm) is to be established by tests, it shall be done in advance of the construction, using prisms built of similar materials under the same conditions with the same bonding arrangement as for the structure. In building the prisms, moisture content of the units at the time of laying, the consistency of the mortar, the thickness of mortar joints and workmanship shall bo the same as will be used in the structure. Assembled specimen shall be at least 40 cm high and shall have a height to thickness ratio (h/t) of at least 2 but not more than 5. If the h/t ratio of the prisms tested is less than 5 in case of brickwork and more than 2 in case of blockwork, compressive strength values indicated by the tests shall be corrected by multiplying with the factor indicated in table 1.2.Prisms shall be tested after 28 days between sheets of nominal 4 mm plywood, slightly longer than the bed area of the prism, in a testing machine, the upper platform of which is spherically seated. The load shall be evenly distributed over the whole top and bottom surfaces of the specimen, and shall be applied at the rate of 350 to 700 kn/min. The load at failure should be recorded.(6)

B-2. CALCULATION OF BASIC COMPRESSIVE STRESS

B-2.1 Basic of masonry shall be taken to be equal to 0.25 f'm where f’m is the value of compressive strength of masonry as obtained from prism test.

CORRECTION FACTORS FOR DIFFERENT H/T RATIOS

RATIO OF

HEIGHT TO

THICKNESS(H/T)2.00 2.50 3.00 3.50 4.00 5.00

CORRECTION

FACTOR FOR

BRICK WORKS*0.73 0.80 0.86 0.91 0.95

1.00

CORRECTION

FACTOR FOR

BLOCK WORK*1.00 _ 1.20 _ 1.30 1.37

*INTERPOLATION IS VALID FOR INTERMEDIATE

VALUES.

Table 1.2 correction factors for different H/T raio

CONCLUSION AND RESULTSFly ash utilization in the country has remained less than 10% during the past 5 years and it might take several years to reach the final goal of cent percent utilization. Every year nearly 70 million tones of ash is produced in India, of which NTPC

stations alone contribute to the extent of about 22 millon tones.The results shows the Fly-ash bricks are more safe, economical and having higher strength compare to conventional bricks.

Further Fly ash bricks have many advantages like -LightweightEconomicalenvironmental friendlysaving of fertile land, pure watermore compressive strengthUse of wastage etc.

FUTURE SCOPE

Prepare a mortar for fly-ash bricks from waste material with different praportion like 1:4,1:5,1:6.carry out prism testing 7,14 days and find basic compressive strength, economical, other etc.compare clay bricks basic compressive strength with fly-ash bricks.

ACKNOWLEDGEMENT

Author are highly thankful to guid prof. J.R.Pitroda sir who motivate and giving guidance. author also giving thank to HOD prof.J.J.Bhavsar sir and other faculty of civil engineering branch.

REFERENCES

1. Work shop on “Training program on utilization of fly ash in construction industries” Dec 29,30,31,2010 B.V.M.Engineering v.v.nagar

2. http://en.wikipedia.org/wiki/Nomogram3. Thesis report on “Techno-economical study of Fal-g bricks in

central region of gujart-india”.4. Nomograms for thickness of masonry walls SP : 10-19755. Building construction by b.c.punamia6. National building code sp7:19837. Www.Info.flyash.com8. WWW.NTPC.COM



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