Review University Without Borders for the Open Society (RUFSO)

ISSN: 2313-285X

Volume 20, 2020

Structural design of a three storey modern clinic in Musanze District –Rwanda.

UWASE FURAHA Justine

E-mail: jfurahauwase@gmail.com

ABSTRACT

This project consists of the structure design of three storied modern clinic in Musanze district considering

lack of sufficient Hospital and clinic and also low capacity of health care in MUSANZE District, Muhoza

sector, the researcher have influenced to design a modern clinic according to the district master plan. After

making a deep analysis on this case and on the issues mentioned above, have made a structure design of a

modern clinic of three storied building with all required rooms suitable for good health facility, and by

implementing this project, the entire community will be having a nearest health care facility, where the

reduction of population to the district hospital will also be reduced. With the modern clinic, the new job will be

created and achieving development as in Rwandan vision set. The theory of reinforced concrete structure, the

properties of materials for reinforced concrete and the test through before and during execution will ensure

safety and security to users. As the aim of this project is to give adequate health care to the entire community

and surrounding population, also improving personal capacity of handling the structural design tasks and where

academic interest are concerned. Software programs were used to draw plans, analyze and design the structures

basing on BS code of practice; all this found in the present report.

Keywords: clinic, health care, structures, building

1. INTRODUCTION

Musanze is Rwanda's most mountainous district,

containing the largest part of the Volcanoes

National Park at Kinigi.

It is also in this district that most of

Rwanda's mountain gorillas are found, making it the

most popular tourist destination in the country. And

has the area of 530 km2 (200 sqm), its total

population 368,264, (398986 projection 2016)

density of 690/km2 (1,800/sqmeter). Its capital city

is Ruhengeri, which is also sometimes known as

Musanze. (Inzego.doc — Province, District and

Sector information from MINALOC, the Rwanda

ministry of local government DATE 2014/6/9)

Review University Without Borders for the Open Society (RUFSO)

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Volume 20, 2020 MUSANZE town has only one hospital that is

Ruhengeri hospital, began with the opening of a

dispensary in 1964. Today, it has 409 beds,

including a 100-bed maternity ward, and serves a

population of more than 350,000;15 Health Center,

1 Prison Dispensary, 6 Private Clinics, and 15

Health Posts. The District Counts over 302 Nurses

working in Hospital and Health Centers, 6

Specialists and 16 General Practitioners (June 2016

Situations).

Due to this large number of people, those who

don’t get well health care nearly decide to travel

far away from the district to other hospitals or

clinics or neighboring instead for more treatment

and the clinic called Polyclinic de Musanze

precisely in Muhoza which currently does not

working with some insurance like MMI and RSSB

the former RAMA. (The New Times/Rwanda 24

Nov 2014 on allAfrica.com,

http://allafrica.com/stories/201411240029.html)

This mentioned case pushed us to entitle our project

“structural design of three storied modern

clinic” fulfilled with requirement and which will

provide health care and safety to the users according

to the British standard.

2. METHODS

The researcher choose a survey research design

because it best served to answer the questions and

the purposes of the study. The survey research is

one in which a group of people or items is studied

by collecting and analyzing data from only a few

people or items considered to be representative of

the entire group. A quantitative approach was

followed. Burns and Grove define quantitative

research as a formal, objective, systematic process

to describe and test relationships and examine cause

and effect interactions among variables. Surveys

may be used for descriptive, explanatory and

exploratory research. A descriptive survey design

was used. A survey is used to collect original data

for describing a population too large to observe

directly .A survey obtains information from a

sample of people by means of self-report, that is,

the people respond to a series of questions posed by

the investigator.

3. RESULTS

Concrete have a wide range of strengths and stress-

strain curves which is represented by typical curve

for concrete in compression.

Figure 1: stress-strain curve for concrete in

compression (Mosleyet al, 2007)

Steel Reinforcement

Steel reinforcement for concrete consists of bars,

wires, and welded wire fabric, all of which are

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Volume 20, 2020 manufactured in accordance with ASTM standards.

The most important properties of reinforcing steel

are:

1. Young’s modulus, E

2. Yield strength, fy

3. Ultimate strength, fu

4. Steel grade designation

5. Size or diameter of the bar or wire, Ø

Reinforced Concrete

Reinforced concrete is a strong durable building

material that can be formed into many variety

shapes and sizes ranging from a simple rectangular

column, to a slender curved dome or shell. Its utility

and versatility is achieved by combining the best

features of concrete and steel.

Table 1: Different properties of steel and concrete (Mosley et

al, 2007)

Concrete Steel

Strength in

tension

Poor Good

Strength in

compression

Good Good, but

slender bars

will buckle

Strength in

shear

Fair Good

Durability Good Corrodes if

unprotected

well

Fire Good Poor-suffers

resistance rapid loss of

strength at high

To

Characteristic value of load

Characteristic service loads are the maximum loads

which will not exceed the design life of the

structure or actual loads that the structure is

designed to carry. The following load should be

used in

Characteristic dead load GK; mean the permanent

weight of the structure such as finishes, fixture and

partitions.

Characteristic imposed load QK; is the loads

produced by the intended occupancy or user,

including the weight of movable partitions,

distributed, concentrated, impact and inertia loads.

Characteristic wind load WK; is the load due to

the effect of wind pressure or suction

The characteristic load in each case should be the

appropriate load as defined in and calculated in

accordance with BS 6399-1, BS 6399-2 and BS

6399-3

Partial safety factors for load γf

The design load for a given types of loading and

limit state is obtained from: Gkγf or Qkγfor Wkγf,

Where γf: is the appropriate partial factor. In ULS

design of the whole or any part of a structure each

of the combinations of loading given in table 2.1

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Volume 20, 2020 should be considered and the design of cross-

section based on the most severe stresses produced.

Table 2: Load combination and value of γf for the ULS (table

2.1,BS 8110)

Material Properties

Characteristic strength of reinforcement is given in

BS 4449, BS 4482 and BS 4483 and is shown in

Table 3.1. Design may be based on the appropriate

characteristic strength or a lower value if necessary

to reduce deflection or control cracking.

2.7. STRUCTURAL ELEMENTS AND

FRAMES

According to the loading system, the complete

building structure can be broken down into the

following elements:

Beams:horizontal members carrying lateral loads

(Linear structure),

Slabs:horizontal plate elements carrying lateral

loads (structure with small thickness or Flat

Structure)

Columns:vertical members carrying primarily

axial load but generally subjected to axial load and

moment,

Walls:vertical plate elements resisting vertical,

lateral or in-plane loads

Bases and foundations: The pads or strips

supported directly on the ground that spread the

loads from columns or walls so that they can be

supported by the ground without failure.

Design of beam

Beams are rigid structural members designed to

carry and transfer transverse load across space to

supporting element.

Rectangular beam:

The procedural calculations during the design of the

rectangular beam:

Computing the ultimate load from the slabs and

dead loads of the beam, this load is used to calculate

the design bending moment M.

using formulas to find out the value of K, then

check if compression bars are required

By using the clause 3.4.4.4 of BS 8110, calculate

the tensile reinforcement required.

a. If the compression reinforcement are needed

(In tension zone)

In compression zone)

b. If the compression reinforcement are not required

T and L beam:

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Volume 20, 2020

When the neutral axis lie in the flange, the

normalized moment is given by:

K=M/fcubd2, then the moment arm

≤ 0.95d, the deep

of the neutral axis and the deep of

the compression bloc is a= 0.9x.

If a ≤ hf, the procedures of calculations as are

exactly the same as previously rectangular beam

design. Taking the width of the beam as bf.

Compression bar is required when K> K'.

If a>hf when M≤ βffcubd2 and hf≤ 0.45d, then

where

Β=0.45 )( )+0.15

Otherwise the calculation has two parts. The first

part is for balancing the compressive force from the

flange, Cf, and the second part is for balancing the

compressive force from the web, Cw, as shown in

Figure above. In that case, the ultimate resistance

moment of the flange is given by: Mf= 0.45fcu (bf-

bw)hf(d-0.5hf).The moment taken by the web is

computed as: Mw=M-Mf and the normalized

moment resisted by the web is given by:

Kw=Mw/fcubwd2.

If Kw ≤ 0.156 the beam is designed as a singly

reinforced concrete beam. The reinforcement is

calculated as the sum of two parts, one to balance

compression in the flange and one to balance

compression in the web.

Where

≤ 0.95d

If Kw > K', compression reinforcement is required

.The ultimate moment of resistance of the web only

is: Muw=K’fcubwd2

The compression reinforcement is required to resist

a moment of magnitude Mw− Muw. The

compression reinforcement is computed

as: Where, d’ is the depth of

the compression reinforcement from the concrete

compression face, and if

If

Shear design

An accurate analysis for shear strength is not

possible. The problem is solved by establishingfirst

the strength of concrete in shear by test. The shear

capacity is represented by the simple formula to

calculate the nominal shear stress given in BS8110:

Part 1, clause 3.4.5.2: (T.J. MACGLEY and

B.S.CHOO, 1990).

v'c

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Horizontal length of the crack, d/sv

number of links crossing the crack

fyv characteristic strength of the links

The shear force to be taken by the links is equated

to the strength of the links, i.e.

(From T.J.

MACGLEY and B.S.CHOO, 1990)

Deflection check

Table 3: Basic span/effective depth ratio for rectangular or

flanged beams. (Table3.9, BS 8110)

Support conditions Rectangular beam Flanged beams,

bw/b≤0.3333

Cantilever 5.6

Simply supported 20 26

Continuous 16.0 20.8

The value of table 4 should be multiplied by

except for cantilevers where the design should be

justified by calculation.

Modification factor for tension reinforcement

Modification factor for tension reinforcement are

given (in BS8110 Part1-1997 )

Modification factor = 0.55

The design service stress in the tension

reinforcement Fs

Modification factors for compression

reinforcement

. Modification factor for compression reinforcement

are given (in BS8110 Part1-1997)

1

4. DISCUSSION

4.1. Limitation

Generality

Slabs are the floor system of structure but can also

be used in roofs, walls of building and as decks of

bridges. Slabs can take many forms such as in-situ

solid slabs, ribbed or pre-cast unit. Slabs may either

span in one direction or two directions.

One way slab and two ways slab ,

where ly and lx is long and short span respectively

getting the stress produced by the load and

surcharges in functions of different parameters.

Ly/lx (x-axis and y-axis)

Procedures of designing a slab

a. Estimation of minimum thickness of slab; the

first estimation is done by using the ratio of the

short span d. the practice code 8 110 gives the

following values according to the condition of the

support. Design load is found like beam.

b. Determining the design moment

Design moment in each direction is calculated by

the following formulas:

Msx = βsx*Nlx2for the short spanand Msy =

βsy*Nly2for the long span. Where βsx is

coefficients of short span and βsyis coefficient

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Volume 20, 2020 applied for long span from Table 3.14 in the code.

Lx is the length of the shorter span; ly is the length

of the longer span, n is the total ultimate load per

unit area, which is; 1.4Gk + 1.6Qk

See appendix table 3.23. Ultimate moments and

shears in one-way spanning slabs. (Table 3.12,

BS 8110)

K = M/fcu * b * d2, then Z = d [0.5 + (0.25 -

k/0.9)1/2] ≤ 0.95d

AS= and ASmin= , if As < Asmin

provide Asmin

c.DeflectionThe deflection is found in the mid span

and is done by using bending moment.1/d = 26

d. Modification factor

M.D= and

If M.D > 2 take M.D= 2 permissible ratio = (1/d) *

2 or M.D and then real ratio If the permissible

ratio is greater than real ratio, the section of slab is

enough and adequate it means there is no deflection.

e. Crack check

The code of practice also states that the distance

between the steel bars may be greater than 3d in

order to prevent cracks in the slab.Bars in each row

should be vertically in line and the vertical distance

between bars should be not less than 2h agg/3.

When the bar size exceeds h agg + 5 mm, a spacing

less than the bar size or equivalent bar size should

be avoided. (BS 8110 Part 1-1997, clause 3.12.11.)

Minimum distance between bars. The horizontal

distance between bars should not be less than h agg

+ 5 mm, where h agg is the maximum size of coarse

aggregate. Where there are two or more rows: the

gap between corresponding.

Design of column

Columns are structural members in buildings

carrying roof and floor loads to the foundations.

Columns primarily carry axial loads, but most

columns are subjected to moment as well as axial

load. The load at the columns is distributed directly

on the column of down storey or at the foundation.

(From T.J. MACGLEY and B.S.CHOO, 1990)

General Code provisions

General requirements for design of columns are

treated in BS8110: Part 1, section 3.8.1. The

provisions apply to columns where the greater

cross-sectional dimension does not exceed four

times the smaller dimension. The code classifies

columns as:

1. Short columns when the ratios and are both

less than 15 for braced columns and less than 10 for

unbraced columns and

2. Slender columns when the ratios are larger than

the values given above.

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Volume 20, 2020 Where b is the width of the column cross-section, h

is the depth of the column Cross section, is the

effective height in respect of the major axis and

is the effective height in respect of the minor

axis.

Practical design provisions

The minimum number of longitudinal bars in a

column section is four for rectangle and six for

circle. Percentages of steel ranging from 0.4% to a

maximum of 6% for vertically cast Columns. The

minimum percentage of reinforcement is given in

Table 3.27 of the code for both grades 250 and

grade 460 reinforcement as

Where the area of steel in compression and Acc

is is the area of concrete in compression

a. Design for links

1. The diameter of links should not be less than 6

mm or 1/4 of diameter of the largest longitudinal

bar;

2. The maximum spacing is to be 12 times the

diameter of the smallest longitudinal bar;

3. The links should be arranged so that every corner

bar and each

b. Short braced axially loaded columns

Both longitudinal steel and all the concrete assist in

carrying the load. The links prevent the longitudinal

bars from buckling. The ultimate load N that a short

braced axially loaded column can support is:

N = 0.4fcuAc + 0.75Ascfy. Where Ac is the net

cross-sectional area of concrete in the column and

sc is the area of vertical reinforcement. Thus in the

design equation for short columns the effect of the

eccentricity of the load is taken into account by

reducing the capacity for axial load by about

10%.The ultimate load is given by the expression .

N = 0.35fcuAc + 0.67Ascfy

Biaxial bending

When it is necessary to consider biaxial bending

and in the absence of more rigorous calculations in

accordance with 3.4.4.1, symmetrically-reinforced

rectangular sections may be designed to withstand

an increased moment about one axis given by the

following equations

a. For

b. For

Where ß is the coefficient obtained from Table 3.22

of BS 8110

Design charts: consist of determining the

compressive force and the bending moment, and

then calculate the following ratio and and

select the design chart according to and and

used and finally check if the provided area lies

within limit.we calculate the Area of steel

from the expression

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Volume 20, 2020 See appendix figure 3.94 column design chart

(based on chart no.27 BS8110 part 3)

Stairs Case

Generality

A set of step which lead from one level of building

to another (Cambridge Advanced Leaner’s

dictionary).Stairways are sloping one-way spanning

slabs. Two methods of construction are used.

Transverse spanning stair slabs

Transverse spanning stair slabs span between walls,

a wall and stringer (an edge beam), or between two

stringers.

Stairs are other types of slabs whose use to connect

the different floors of the structure and hence enable

movement from the floor to the next. They are

designed in the same way as beams by considering

a unit width of the slabs.

BRITISH STANDARD

Using the British Regulations and Standard for

reinforced concrete design (BS8110, 6399) gives

the information to consider during design, some of

those information are the followings:

Achievement of this Project will be done by

collecting the real data and put them into practice.

The methods that will be followed in this proposed

project are:

Taking data and treat them using formulas from

different parts of BS.

Interpretation of drawings, charts and tables.

Close contact with the supervisor and following

BEAM DESIGN

The most loaded beam is that has a large influence

area on it, it is the beam 5 which has five spans.

Figure 2.The most loaded beam.

4.2. Recommendations

Review University Without Borders for the Open Society (RUFSO)

ISSN: 2313-285X

Volume 20, 2020 During conducting study on this project, many

problems and challenges were encountered that is

why we are suggesting the following

recommendations:

Generally: During implementation of this project;

specifications of concretes and steel reinforcements

should be respectful to get good and secured

building. Qualified personnel should be regarded

indispensable in this because construction materials

and equipment should be well secured and

maintained.

4.3. CONCLUSION

This project work has the purpose of designing the

reinforced Concrete structural of three storied

modern clinic in Muhoza sector referring to

Rwanda vision, for solving out the problem of

health facilities, this overall project will help those

who will be interested in using it especially the

people living in Musanze District and students who

will perform their projects in the same field.

As far as District is concerned, implementing of this

present project will be easy as it is analyzed and

designed according to British Standard.

LIST OF ABBREVIATIONS

BS British standard

CAD Computer Aided Design

C.P Code of Practice

F.E.M Fixed End Moment

Max Maximum

MININFRA Ministry of infrastructure

SLS Serviceability limit state

UDL Ultimate design load

ULS Ultimate limit state

ACKNOWLEDGMENT

We thank everyone who contributed to the success

of this project. We sincerely express our deep

gratitude.

Authors’ contributions

JR conceptualize the idea and both others

contributed equally thereafter.

Authors’ affiliation

Both authors are affiliated to Distance production

House University/ IST Burkina Faso.

Conflict of interest

We declare not conflict of interest

Funding

None

REFERENCES

1. MININFRA, Rwanda building control regulations,

Second edition, 2012.

2. S.S.Ray, Reinforced concrete, analysis and design,

1995.

3. T.Ndabamenye, Reinforced concrete design I,

Lecturer note,2016-2016

Review University Without Borders for the Open Society (RUFSO)

ISSN: 2313-285X

Volume 20, 2020 4. T.J.MacGinley and B.S.Choo, Reinforced Concrete

Design Theory and Examples, Second edition1990

5. W.H.Mosley and J.H.Bungey Reinforced Concrete

Design, Fourth Edition, 1990.

6. R. Chudley and ROGER

GREENO(14JULY 2005)’’construction of

technology’’ fourth edition

7. J.T.Grndy.1977 Dump

proof coat on footing ,Construction technology

volume 1-2,200,113-123

8. BS6399-1:1996,loading for building

9. BS5950-1:2000 structure use of steelwork in

building

10. S.S Ray, 1995. Reinforced concrete Analysis and

Design,543,385-405

11. Fred hall and Roger,2007 building services Hand

book fourth edition

12. BRITISH STANDARDS INTITUTION, structure

use of concrete; Part 1: code of practice for

design and construction, London (1997)

13. Andy Press man –Architectural Design Potable

Handbook, 2001.

Websites

1. http:// www.webcrowler.com

2. http:// www.eBookstore.tandf.co.uk.

3. http://www.wikipedia.org