Development of Some Design Charts for Slab, Beam, Column and Flat Plate

Nitish Ranjan Gaine∗

Nazma Khatun∗∗

Suite Kumar∗∗∗

Abstract

The aim of this project is to develop some design charts of slab, beam, column

and flat plate. In this project some equations were also developed from design

charts. These help a design engineer to design instantly and approximately of

those components without any calculation. Moreover, the developed spreadsheets

can be used for required design information. Design charts of slab, beam, column

and flat plate as well as equations with respect to various areas span length,

panel ratios, material properties and superimposed loads were developed in this

project. Most of the curves from correlations are found two degree for beams and

two way slabs, some curves of one way slabs and columns are linear. Design of

these components requires much time. But if some design charts are available it is

easy to design these important components. Moreover, it is easy to carry these

charts everywhere.

Keywords: design charts, span length, panel ratios, superimposed loads, material properties.

Introduction

For various civil engineering designs different software are widely used now a days. But in

any case where computer is not provided or time is not sufficient for manual design, design

charts may help a civil engineer to design slab, beam, column etc. instantly and

approximately. The equations developed from design of various components will help an

engineer as a guide to solve the structural design for varied size, shape, etc.In this study it

will have to establish some design charts for some structural member, namely slab, beam,

column and flat plate.

∗

Khulna University of Engineering and Technology, Khulna, Bangladesh. ∗∗

Khulna University of Engineering and Technology, Khulna, Bangladesh. ∗∗∗

Chittagong University of Engineering and Technology, Chittagong, Bangladesh.

Banglavision ISSN: 2079-567X

Vol. 13 • No. 1 • January 2014

118 Banglavision Vol. 13, No. 1, 2014

“Design is the determination of the general shape and all specific dimensions of a particular

structure so that it will perform the function for which it is created and will safely withstand

the influences, which will act on it throughout its useful life”.

“In reinforced concrete construction, slabs are used to provide flat, useful surfaces. A

reinforced concrete slab is a broad, flat plate, usually horizontal, with top and bottom

surfaces parallel or nearly so. It may be supported by reinforced beams, by masonry or

reinforced concrete wall, by structural steel member, directly by columns or continuously by

the ground”. Slabs may be supported on two opposite side only in which case the structural

action of the slab is essentially one way, the loads being carried by the slab in the direction

perpendicular to the supporting beams. If the ratio of length to width of one panel is larger

than 2, most of the load is carried in the short direction to the supporting beams and one way

action is obtained, even through supports are provided on all sides. There may be beam all

sides so that two way slab action is obtained. Normally the ratio of length to width of one

panel is smaller than 2.Concrete slabs may in some cases be carried directly by columns

without the use of beams or girders. Such slabs are described as flat plate and are commonly

used where spans are not large and loads not particularly heavy.Reinforced concrete beams

are non-homogeneous in that they are made of two entirely different materials. This type of

beam is composed of concrete in which steel bars are embedded. In this beam concrete takes

up the compressive stresses whereas the steel resists the tensile stresses produced in the beam

during bending. In a reinforced concrete beam, the concrete adheres firmly to the steel.

Column is defined as concrete compression member. Its unsupported length is more than

three times the least dimension of the cross-section. Particularly columns are members

subjected to both direct load and moment.

A flat-plate floor is a two-way slab system consisting of a uniform slab that rests directly on

columns and does not have beams or column capital .In this case the column tends to punch

through the slab, producing diagonal tensile stresses .Therefore a general increase in the slab

thickness is required or special reinforcement is used.

Results and discussion

2.1 To develop design chart for the one way slab (4 side-supported) with; (a) The variation of

Various areas for constant span ratio (L/B). (b) The variation of short span for constant

long span.

Development of Some Design Charts for Slab, Beam, Column and Flat Plate 119

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Development of Some Design Charts for Slab, Beam, Column and Flat Plate 121

2.2 To develop design chart for the two way slab for various span ratio (B/L) with constant

long span, when (a) all side continuous.(b)one long and two short side continuous. (c)one

long and one short side continuous. (d)one short and two long side continuous.

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Development of Some Design Charts for Slab, Beam, Column and Flat Plate 123

2.3 To develop design chart for the flat plate for fixed span ratios but different panel areas.

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2.4 Design chart for column (a) For 10”, 12”, 14” and 16” dia. circular columns at different

loadings and constant steel ratio.(b) For 10”x10”, 12”x10”, 12”x12” and 14”x12”

rectangular columns at different loadings and constant steel ratio.

Development of Some Design Charts for Slab, Beam, Column and Flat Plate 125

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2.5 Design chart for the beam (a) with the variation of span lengths for constant x-section. (b)

with the variation of f’c for constant fy.

Development of Some Design Charts for Slab, Beam, Column and Flat Plate 127

Conclusion

Design charts may help a civil engineer to design slab, beam, column etc. instantly and

approximately when time is not sufficient. I had prepared design charts only for four cases

though there has nine cases and I had prepared design charts considering f′c = 3ksi & 40ksi

and fy = 40 ksi & 60 ksi for the two way slab. So another design charts can be prepared for

the rest. The charts can be used as ready reference for approximate design of slab, beam,

column and flat plate.

Acknowledgement

The authors would like to express their gratefulness to the Department of Civil Engineering,

Khulna University of Engineering and Technology, Bangladesh for co-operation during the

period of works.

References:

Arthur. H, Darwin, David and Dolan Charles. W. (2003). “Design of Concrete Structures”,13th

edition, McGraw-Hill, New York.

Nilson, Arthur. H, Darwin, David and Dolan Charles. W. (2003). “Design of Concrete

Structures”, 7th

edition, McGraw-Hill, New York.

Hassoun, M. Nadim, (1998). “Stuctural Concrete”, ADDISON-WESLEY

Khan, Abul Feraz. Rahman, Engr. Shaifur, (1993) ”REINFORCED CONCRETE MANUAL AND

BUILDING PLAN”, 2nd

edition, Farah Publishers

Das, Susil Kumar, (2005). "Treasure of R.C.C. Design"