COVENANT UNIVERSITY

ALPHA SEMESTER TUTORIAL KIT (VOL. 2)

P R O G R A M M E : B U I L D I N G T EC H

300 LEVEL

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DISCLAIMER

The contents of this document are intended for practice and learning purposes at the undergraduate

level. The materials are from different sources including the internet and the contributors do not

in any way claim authorship or ownership of them. The materials are also not to be used for any

commercial purpose.

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LIST OF COURSES

*BLD311: Construction Technology I

BLD313: Building Material Science

*BLD314: Building Thermodynamics

BLD315: Structural Theory I

*BLD316: Building Service and Equipment I

*BLD317: Principles of Measurement and Building Work

*BLD318: Building Maintenance I

*Not included

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COVENANT UNIVERSITY CANAANLAND, KM 10, IDIROKO ROAD

P.M.M 1023, OTA, OGUN STATE, NIGERIA. TITLE OF EXAMINATION: B.Sc. EXAMINATION

COLLEGE: SCIENCE AND TECHNOLOGY

SCHOOL: ENVIRONMENTAL SCIENCES

DEPARTMENT: BUILDING TECHNOLOGY

SESSION: 2015/2016 SEMESTER: ALHPA

COURSE CODE: BLD 313 CREDIT UNIT: 2.0

COURSE TITLE: BUILDING MATERIALS SCIENCE

COURSE LECTURERS: MR. I. OMUH & MR. A. O. AFOLABI

MARKING GUIDE

1. (a). State five (5) differences between thermoplastics and thermosets

Answer:

4

(5 marks).

(b). List ten (10) properties of plastics

Answer:

Properties

Can be moulded to any desired shape or size and have high tensile and compressive strength

Easy to work upon

Light in weight and a few varieties are glossy like glass

Not attacked by insects and fungi

Available in desired colour and texture

Require little maintenance

Good electrical insulators and have low thermal conductivity

Shock absorbing material

High strength to weight ratio

High resistance to weathering conditions

Corrosion resistance

Painting and polishing not required

High refractive index

High coefficient of thermal expansion

Low manufacturing cost, hence cheap (5 marks)

(c). What are the undesirable properties of using plastics in building construction?

Answer:

Undesirable Properties

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Deteriorates under prolonged exposure to sun’s ultra violet rays

It has high thermal expansion and high creep

It has low ductility and melting point

It is not fire resistant

Plastic accumulation in the environment causes pollution (3 marks).

(d). List seven (7) applications of plastics in building construction

Answer:

Application of plastics in buildings

Wall Facing Tiles

Flooring Tiles

Flooring Sheets

Roofing Sheets

Water proofing Membrane

Doors and Windows

Water Tanks

Pipes and Sanitary Appliances

Laminated Plastics

Reinforced Plastics e.g. glass fibre reinforced plastics and carbon fibre reinforced plastics.

Permeable Membranes e.g. Geotextiles (7 marks).

(e). Discuss three (3) constituents in the manufacturing of plastics

Answer:

The constituents of plastics are resin, plasticizer, filler, pigment and dye, lubricant and catalyst.

RESIN: This act as binders for holding different constituents together.

PLASTICIZER: They are non-polymeric organic materials added to modify plastic to impart

desirable combination of strength, flexibility and toughness.

FILLER: They are finely divided minerals added up to 50 per cent of the moulding mixture to

increase the hardness, tensile strength, bond, etc. of the final products

PIGMENT: This is added to achieve desired colour of the plastic and should be resistant to the

action of sunlight.

LUBRICANT: This is used to make the moulding of plastic easier to prevent sticking of materials

to the mould for a flawless finish

CATALYST: This is added only in the case of thermosetting plastics to accelerate the

polymerization of fusion resin during moulding operation into cross linked infusible forms.

(3 marks)

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2. (a). Discuss eight (8) defects that can affect timber. Provide neat sketches

Answer:

Chemical stain:- the wood is sometimes discoloured by the chemical action caused with it by

some external agency. This is known as chemical stain.

Star shakes:-these are cracks which extend from bark towards the sap wood. These are usually

confined upto the plane of sap wood. These are wider on outside ends and narrower on inside

ends. They are usually formed due to extreme heat or severe frost during the growth of tree.

Cup shakes:-it appears as curved split which partly or wholly separates annual rings from one

another. It is caused due to excessive frost action on sap present in the tree especially when the

tree is young.

Heart shakes:- these cracks occur in centre of cross-section of tree and they extend from pith to

sap wood in direction of medullary rays. These cracks occur due to shrinkage of interior part of

tree which is approaching maturity. The heart shake divide the tree cross-section into two or four

parts.

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Upsets:-these indicate wood fibres which are injured by crushing or compression. The upsets

are mainly due to improper felling of tree and exposure of tree in its young age to fast blowing

wind.

Wane: This defect is denoted by presence of original rounded surface on manufactured part of

timber

Diagonal grain:-the defect is formed due to improper sawing sawing of timber.it is indicated by

diagonal marks on straight grained surface of timber.

Rind galls:-the rind means bark and gall indicates abnormal growth. Hence peculiar curved

swelling found on the body of tree are known as rind gall. They develop at points from where

branches are improperly cut off or removed. They are rarely found in a tree and the timber in

this part is very weak and not durable.

(4 marks).

(b). List five (5) benefits of using timber over other building materials

Answer:

• The only 100% renewable resource of construction material.

• Renewable resource allows for the direct employment of hundreds of thousands of people

in the Australian building industry (directly and indirectly). Thus improving the local

economy.

• Timber from managed plantations are Greenhouse Gas Reducing.

• Ecologically safe and sound to handle and dispose.

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• Natural variations add aesthetic interest. (5 marks).

(c). List five (5) undesirable properties of using timber

Answer:

Acceptability

Insect and fungi attack

Depletion of Natural Resources

Inadequate research on the material

Lack of quality control (5 marks).

(d). List eight (8) applications of timber in building construction

Answer:

1. Building construction,

2. Construction of house posts,

3. Construction of beams,

4. Construction of rafters,

5. Construction of bridges,

6. Construction of piles, poles and railway sleepers,

7. For making furniture,

8. For manufacturing of veneers and ply woods.

9. For wooden fences

(4 marks).

(e). What is seasoning of timber and list the available types

Answer:

As fresh timber which is obtained from trees contains about 30 to 40 % sap or moisture. This sap

is very harmful for the life of a timber. Therefore, it is necessary to remove that sap by applying

some special methods. All those methods which are used for removing the sap from timber are

collectively termed as seasoning of timber.

The main types of timber seasoning are as under.

(1) Natural Seasoning,

(2) Artificial Seasoning,

(a) Kiln Seasoning,

(b) Chemical Seasoning,

(c) Electric Seasoning,

(3) Water Seasoning (3 marks).

(f). State two (2) ways of preserving timber.

Answer:

There are two main classes of timber preservatives.

(1) Oily substances insoluble in water: Coal tar oil is the best known and widely used preservative

material of this class. It is obtained during the destructive distillation of bituminous coal.

(2) Water soluble salts: Zinc chloride is the most extensively used preservative of this type. It is

clean and odourless.

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Others include;

Charring

The simplest method applied, which does not require any preservative is the charring of timber.

However, it only provides temporary protection. It is particularly applied for cheaper timber in

ground contact.

Dip treatment

In order to protect the timber during seasoning, the boards have to be dipped in a preservative

solution immediately after sawing. The dipping tank can be welded out of half-cut oil drums, or

out of a wooden box lined with plastic sheets. The tank should be placed between the re-saw and

the seasoning sheds to allow an unimpeded workflow.

Brushing/spraying

The minimum solution strength of the preservative applied by this method is 3%. Depending on

the moisture content of the timber and the roughness of its surface, 1 to 3 coatings have to be

applied. However, this method has limited effect only.

Soaking

The timber to be treated can be soaked in a 3 – 5 % solution for up to 8 hours (depending on use

and thickness). Soaking provides better protection than brushing or spraying.

Hot and cold bath

Two open tubs of appropriate length and volume are required to accommodate the timber sizes to

be treated. They should be made of stainless steel in order to withstand the corrosive effects of the

preservative.

(2 marks)

3. (a). Discuss five (5) defects of paint

Answer:

Efflorescence:

This is the formation of crusty, white salt deposits, leached from mortar or masonry as water

passes through it.

Causes :

Failure to prepare surface properly by removing all previous efflorescence.

Excess moisture escaping through the exterior walls from the inside.

Blistering:

The formation of bubbles resulting from localized loss of adhesion and lifting of the paint film

from the underlying surface.

Causes :

Caused by trapped moisture or gases in paint film (more likely in enamels).

Application of alky/oil based paint over a damp surface

Exposure of paint film to dew, high humidity or rain

Cissing:

Causes :

Small impurities in paint (oil, grease) visible at the centre of the hole

Prevention :

Clean surfaces prior to sanding and remove all sanding dust

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Orange Peel:

Causes :

Application of top coat paint in highly viscous form

Use of improper thinner

Prevention :

Sufficient drying time between coats

Use recommended painting system

Peeling:

Causes:

by moisture on the wall,

poor surface preparation or using an incorrect painting system. This defect happens on walls

as well as wood or metal surfaces.

Wrinkling

Causes

When the paint forms film-like undulating waves.

Applying too much paint or drying during high temperatures

Painting on a topcoat before the undercoat is dry can cause this defect to happen.

(5 marks).

(b). Discuss four (4) main ways of preserving metals (4 marks).

Answer:

Electroplating

Painting

Galvanizing

Annealing

Electrolytic Reduction

Chemical cleaning

(c). List six (6) important metals used in building construction

Answer:

Iron (Fe), Zinc (Zn), Copper (Cu), Aluminium (Al), Tin (Sn), Lead (Pb), Chromium, Gold

(Au), Magnesium (Mg), Mercury (Hg), Potassium (K), Silver (Ag)

(3 marks).

(d). List five (5) types of paint

Answer:

Oil based paint

Textured paint

Water based paint

Emulsion paint

Primer

Polymer paint

Clay paint

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Gloss paint

Aluminium paint

(5 marks).

(e). What is an alloy and give three (3) examples

Alloys are made of mixtures of at least one metal with either other metals or with non-metals. E.g.

Steel, Bronze, Brass, Gunmetal, Amalgam, Cast Iron, Pig Iron, Solder

(3 marks).

(f). Discuss the industrial process of producing metals.

Answer:

The term metal production refers to all of the processes involved in the conversion of a raw

material, such as a metallic ore, to a final form in which the metal can be used for some

commercial or industrial purpose.

First Step: Mining

The first step in metal production always involves some form of mining. Mining refers to the

process of removing the metal in its free or combined state from the Earth's surface. The two

most common forms of mining are surface and subsurface mining. In the former case, the metal

or its ore can be removed from the upper few meters of the Earth's surface (3 marks)

Next Step: Purification

In most cases, metals and their ores occur in the ground as part of complex mixtures that also

contain rocks, sand, clay, silt and other impurities. The first step in producing the metal for

commercial use, therefore, is to separate the ore from waste materials with which it occurs. Ore,

naturally occurring rock containing high concentrations of one or more metals that can be

profitably mined. Ore minerals are the minerals within ores that contain the metal.

Step Three: Reduction

Metals always occur in their oxidized state in ores, often as the oxide or sulfide of the metal. In

order to convert an ore to its elemental state, therefore, it must be reduced. Reduction is a

chemical reaction that is the opposite of oxidation. Metals can be reduced in a variety of different

ways.

4. (a). In advertising clay products, state six (6) advantages of using clay products

Answer:

They are strong and durable.

They are available in a variety of shapes, sizes, and colors.

It also has reflective properties, which help to increase the efficiency of heating and cooling

systems.

This type of material is not susceptible to mold or rot, can withstand hurricane-force winds,

and does not shrink and expand with the temperature like wood.

It requires low maintenance.

It highly fire resistant

It mostly does not require finishes such as painting etc. (6 marks).

(b). State four (4) clay products that are used in buildings.

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Answer:

Foundation (as drilling mud-Bentonite, Hard-Core formation)

Floors: as Floor Tiles, Gravuing mixture in Floor Paving and Cement in concrete screeds,

Floor Bricks.

Walls: as Tiles (Ceramic Tiles, Mozaic Tiles in the form of Vitrified and Non Vitrified Tiles),

Plastering, Mortar mixes, Cob, Pisse-du-Terre as well as Sandcrete- Block works. Wall of

refractory. e.g. Bakery, foundry e.t.c.

Ceiling : as Proprietary Ceiling Products e.g Plaster of Paris Ceiling, Asbestos-

Cements/Cellotex Ceilings Boards. Daub and Wattles.

Roofs: Such as Corrugated Roof Tiles, Asbestos-Cement Roofing such as Duke- Villa tiles,

Amiatus, Roof Ridges, e.t.c.

Finishes: Such as Paints, P.O. P. (Plaster of Paris)

Sanitary Products e.g. Water Closet Seats, water Closet Tanks, Bidet Wash Hand Basin of

Ceramic Components, Bath-Tub, e.t.c.

(4 marks).

(c). Differentiate between addition polymerization and condensation polymerization, giving one

example each in the two (2) processes.

Answer:

Addition Polymerization is defined as a reaction that yields a product which is an exact

multiple of the original monomeric molecule e.g. ethylene polymerization to become

polyethylene.

Condensation Polymerization is defined as the reaction between functional monomer

molecules leading to the formation of a polymer with the elimination of small molecules

such as water, HCL etc. e.g. Nylon formed from hexamethylene diamine and adipic acid.

(4 marks).

(d). List four (4) examples of natural polymers. (2 marks).

Answer:

1. Natural rubber

2. Timber

3. Starch

4. Wool or cotton

(e). State three (3) advantages of using Alucobond in buildings.

Answer:

Alucobond is very effective in thermal insulation.

It is effective in sound insulation

It is also very conducive for outdoor applications like highway signage & exterior building

finishes because of the high weather resistant property of aluminum (3 marks).

(f). State three (3) reasons why there is low manufacturing of steel in Nigeria. (3 marks).

Corruption

Epileptic power supply

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Insufficient funds

High reliance on imported products

Poor maintenance culture

5. (a). What is Glass and state four (4) of its application in building construction?

Answer:

GLASS is a hard, brittle substance, which is often transparent and has widespread practical,

technological, and decorative usage in things like window panes, tableware, and optoelectronics. It

is produced by the fusion of sand (SiO2), soda (Na2CO3) & lime (CaO) that produces a transparent

solid when cooled.

Its application in building construction includes;

Design of windows and doors

Glass walls and structural glass assemblies.

Skylights.

Floors and Stairs.

Glazing for security

For decoration

(4 marks).

(b). List eight (8) characteristics of glass as a building material.

Transparency: This property allows visual connection with the outside world. Its transparency can

be permanently altered by adding admixtures to the initial batch mix. By the advent of technology

clear glass panels used in buildings can be made opaque. (Electro chromatic glazing)

U value: The U-value is the measure of how much heat is transferred through the window. The

lower the U-value the better the insulation properties of the glass– the better it is at keeping the heat

or cold out.

Strength: Glass is a brittle material but with the advent of science and technology, certain laminates

and admixtures can increase its modulus of rupture (ability to resist deformation under load).

Greenhouse effect: The greenhouse effect refers to circumstances where the short wavelengths of

visible light from the sun pass through glass and are absorbed, but the longer infrared re-radiation

from the heated objects are unable to pass through the glass. This trapping leads to more heating

and a higher resultant temperature.

Workability: It is capable of being worked in many ways. It can be blown, drawn or pressed. It is possible to

obtain glass with diversified properties- clear, colorless, diffused and stained. Glass can also be welded by

fusion.

Recyclable: Glass is 100% recyclable; cutlets (Scraps of broken or waste glass gathered for re-melting) are used

as raw materials in glass manufacture, as aggregates in concrete construction etc.

Solar heat gain coefficient: It is the fraction of incident solar radiation that actually enters a building through

the entire window assembly as heat gain.

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Visible transmittance: Visible transmittance is the fraction of visible light that comes through the glass.

Energy efficiency and acoustic control: Energy-efficient glazing is the term used to describe the double glazing

or triple glazing use in modern windows in homes. Unlike the original single glazing or old double glazing,

energy-efficient glazing incorporates coated (low-emissivity) glass to prevent heat escaping through the

windows. The air barrier also enhances acoustic control.

(4 marks).

(c). List four (4) types of glass used in building construction.

Answer:

1. Soda Lime Glass: It is mainly a mixture of sodium silicate and calcium silicate. It is fusible at low

temperature. In the fusion condition it can be blown or welded easily. It is colorless. It is used as

window panes and for the laboratory tubes and apparatus.

2. Potash Lime Glass: It is mainly a mixture of potassium silicate and calcium silicate. It is also known

as hard glass. It fuses at high temperature. It is used in the manufacture of glass articles which have

to with stand high temperatures.

3. Potash Lead Glass: It is mainly a mixture of potassium silicate and lead silicate. It possesses bright

lustre and great refractive power. It is used in the manufacture of artificial gems, electric bulbs, lenses,

prisms etc.

4. Common Glass: It is mainly a mixture of sodium silicate, calcium silicate and iron silicate. It is

brown, green or yellow in color. It is mainly used in the manufacture of medicine bottles.

5. Special Glasses: Properties of glasses can be suitably altered by changing basic ingredients and

adding few more ingredients. It has now emerged as versatile material to meet many special

requirements in engineering. (4 marks).

(d). State four (4) natural methods of preserving Bamboos.

Answer:

NON CHEMICAL METHODS OR TRADITIONAL METHOD

Non-chemical methods are otherwise known as traditional methods of preservation, which are

widely used by villagers and are usually done on bamboos used for structural purposes. However,

the treatment cost is almost nothing and thus can be carried out without special equipment. This

method includes curing, smoking, whitewashing and soaking.

a) Smoking

Traditionally, bamboo culms are placed above fireplaces inside the house so that the smoke and

heat rises up can both dry and blackens the culms. It is possible that the process produces some

toxic agents that provide a degree of protection. This is considered an effective treatment against

insects and fungi.

b) White washing

Bamboo culms and bamboo mats for housing construction are often painted with lime. This is

carried out mainly to enhance the appearance, but there is also an expectation that the process will

prolong the life of the bamboo structure by preventing moisture entering the culms. It is possible

that the water or moisture absorption is delayed or in some cases prevented which will provide a

higher resistance to fungal attack. In Indonesia, bamboo mats are tarred and later sprinkled with a

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layer of sand. When this is dry, up to 4 coats of whitewash are applied. Plastering is also a common

practice using cow dung mixed with either lime or mortar.

c) Curing

Bamboo culms are treated during or immediately after extraction and before stacking in the storage

yard. Curing involves harvested culms, with branches and leaves intact, in open air. The leaves

continue to transpire causing the starch content of the culms to fail.

d) Soaking

The culms are submerged in either stagnant or running water or mud for several weeks. This is one

of the best methods to preserve bamboo against the attack of microorganisms and insects.

(4 marks).

(e). State three (3) differences between bamboo and wood.

Answer:

Wood is the hard, fibrous structural tissue that is commonly found in the stems and roots of the

trees. It is a natural composite of cellulose fibers. Bamboo, on the other hand, is essentially a grass

in the Poaceae family of grass. As a grass, bamboo does not have sapwood, heartwood or growth

rings. Its texture is uniform and will range from medium to fine depending on density. The color is

generally pale yellow to almost white. Bamboo differs from wood as it has a hollow stem and lacks

rays or visible pores. In order to process bamboo as a timber, the bamboo fibers are pulled, soaked

and then pressed together with adhesives.

(3 marks).

(f). State four (4) benefits of using natural bamboo for scaffolding purposes.

Answer:

Ecologically Friendly: Bamboo is made from natural vegetation. The bamboo plant is a highly

renewable resource that is able to grow to maturity in as little as three to five years. This is much

faster than hardwood trees which can take upwards of twenty years or more to reach maturity.

Easy Maintenance: Bamboo is relatively easy to maintain.

Water Resistant: This material is slightly more resistant to water damage, stains, and warping than

hardwood materials, although it is still a concern.

Natural Material: The use of natural materials is an important trend in the construction industry right

now. As people are becoming more ecologically conscious they are demanding products that reflect

these values. They are also seeking materials and designs that reject the modern cookie cutter world

and instead focus on individual personality and natural evolution.

Price: This material is priced at about the same level as most hardwood floors. You will often find

bamboo ranging from about two dollars to eight dollars per square foot. You should avoid bargain

basement materials as they are often lower quality castoffs

(4 marks).

(70 marks)

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COVENANT UNIVERSITY. CANAANLAND, KM 10 IDIROKO ROAD

P.M.B. 1023 OTA. OGUN STATE, NIGERIA.

TITLE OF EXAMINATION: ALPHA SEMESTER EXAMINATION.

COLLEGE: COLLEGE OF SCIENCE AND TECHNOLOGY

SCHOOL: SCHOOL OF ENVIRONMENTAL SCIENCES

DEPARTMENT: BUILDING TECHNOLOGY DEPARTMENT

SEMESTER: ALPHA

COURSE CODE: BLD 315 CREDIT UNIT: 3

COURSE TITLE: STRUCTURAL THEORY 1

INSTRUCTION: ANSWER QUESTION 1 AND ANY OTHER THREE (3) QUESTIONS.

TIME: 3 HOURS

1. Use the Hardy Cross method of moment distribution and analyse the beam shown in Figure

Q1. Determine the support moments, draw the shear force and bending moment diagram

for the continuous beam

(25 marks)

Fig Q1

2. (a) What do you understand by the term statical determinacy and when is a structure said to

be statically indeterminate?

(5 marks)

(b). Determine using Clapeyron’s three moment equation method, the support moments

and shear forces for the continuous beam shown in Fig Q2 and draw the shear force and

bending moment diagrams respectively

(10 marks)

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Fig Q2

3. Using the method of joints, determine the force in each member of the truss shown in Fig

Q3 and indicate whether the members are in tension or compression.

(15 marks)

Fig Q3

4 (a). Briefly write about five (5) different structural forms you know. Use illustrations where

necessary.

(8 marks)

(b). Determine the statical determinacy, indeterminacy or instability of the following

structures shown in fig Q4

(5 Marks)

Fig Q4

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(c). Using a simple flow chart, show the basic phases of structural design from planning to

construction.

(2 marks)

5. (a).Using the method of double integration, determine the expression for the maximum

deflection of the cantilever shown in Fig 5a

(5 Marks)

Fig Q5a

(b). Using the moment area method, determine the deflection at the position of the

concentrated load, P in the fig Q5b. Use the following data; a = 2m ; L = 6m ; P = 15kN, I

= bd3

/12; Take E = 2 x 105

N/mm2

; b = 100mm and d = 200mm

(10 Marks)

Fig Q5b

6. a. Write about four types of structural loads. Use illustrations where necessary. (2 marks)

b. Using Macaulay’s method of double integration, shown that the maximum deflection of

a simply supported beam of length L and loaded with a UDL of wKN/m is 5𝑤𝐿4

384𝐸𝐼 (5

marks)

c. Five ropes are tied to a small metal ring. At the end of each rope five students are

pulling, each trying to move the ring in their direction. If we look down from above, the

forces and directions they are applying are shown in Fig Q6. What is the force that

needs to be applied to the ring to keep it in equilibrium and in what direction should it

be applied? (8 marks)

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Fig Q6

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\

COVENANT UNIVERSITY. CANAANLAND, KM 10 IDIROKO ROAD

P.M.B. 1023 OTA. OGUN STATE, NIGERIA. TITLE OF EXAMINATION: B.SC EXAMINATION.

COLLEGE: COLLEGE OF SCIENCE AND TECHNOLOGY

SCHOOL: SCHOOL OF ENVIRONMENTAL SCIENCES

DEPARTMENT: BUILDING TECHNOLOGY DEPARTMENT

SESSION: 2014/2015 SEMESTER: ALPHA

COURSE CODE: BLD 315 CREDIT UNIT: 2

COURSE TITLE: STRUCTURAL THEORY 1

MARKING SCHEME

1.

From the moment distribution,

JOINT AB BA BC CB CD DC

BENDING MOMENT

(kNm)

0 34.53 -34.53 42.58 -42.58 56.87

SIMPLE SHEAR (kN) 24 16 30 30 62.5 62.5

ELASTIC REACTION

(kN)

-6.91 6.91 -1.61 1.61 -2.86 2.86

SHEAR FORCE (kN) 17.09 22.91 28.39 31.61 59.64 65.36

Below is the moment and shear force diagram

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2. (a) statical determinacy denotes the state of a structure when its loads and reactions can be

determined solely by using the equations of equilibrium. When the equations of

equilibrium cannot be used to analyse a structure, it is statically indeterminate.

(b)

From inspection MA = MD = 0

For spans AB-BC

20MB + 5MC = 1505.125 (1)

For Span BC-CC’

5MB + 10MC = 1105 (2)

Solving (1) and (2) simultaneously,

MC= 83.28kNm

MB= 54.44kNm

SFAB = 6.61 kN

SFBA = 28.39 kN

SFBC = 84.23 kN

SFCB = 85.77 Kn

3.

S/NO. MEMBER TENSION (kN) COMPRESSION (kN)

1 AB 30

2 AK 50

3 BC 30

4 BK 5.78 36.67

5 CK 12.5

6 CJ 13.33

7 CH 4.16

8 CD 35

9 DE 37.5

10 DH 3.33

11 DG 4.16

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12 EF 37.5

13 EG 53.33

14 FG 62.5

15 GH 35

16 HJ 32.5

17 JK 22.5

4. (a)

i. Cables carry applied loads & develop mostly tensile stresses - Loads applied through

hangers - Cables near the end supporting structures experience bending moments and

shear forces.

ii. Arches carry applied loads and develop mainly in-plane compressive stresses; three-hinged,

two-hinged and fixed arches - Loads applied through ribs - Arch sections near the rib

supports and arches, other than three-hinged arches, experience bending moments and

shear forces.

iii. Truss is a structure that "consists of two-force members only, where the members are

organized so that the assemblage as a whole behaves as a single object".[1]

A "two-force

member" is a structural component where force is only applied to two points. Although this

rigorous definition allows the members to have any shape connected in any stable

configuration, trusses typically comprise five or more triangular units constructed with

straight members whose ends are connected at joints referred to as nodes.

iv. Beam is a structural element that is capable of withstanding load primarily by

resisting bending. The bending force induced into the material of the beam as a result of

the external loads, own weight, span and external reactions to these loads is called

a bending moment. Beams are characterized by their profile (shape of cross-section), their

length, and their material.

v. Surface structures; these are structures made from thin materials that have been stretched

or curved or folded to gain strength. They are sometimes referred to as thin plates and

shells, the surfaces may be made of rigid material such as reinforced concrete. They could

be of shaped as folded plates, cylinders, etc. Examples include the O2 arena, London.

(b)

i. Statically indeterminate to the 1st

degree

ii. Statically determinate

iii. Unstable

iv. Statically indeterminate to the 2nd

degree

v. The structure is unstable

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5. (a) Dead loads, Live loads, Earthquake loads, wind loads

(b)

EIy′′=0.5wLx−wx(0.5x)

EIy′′=0.5wLx−0.5wx2

EIy′= 0.25wLx2

−1/6wx3

+C1

EIy=1/12wLx3

−1/24wx4

+C1x+C2

At x = 0, y = 0, therefore C2 = 0

At x = L, y = 0

0=1/12wL4

− 1/24wL4

+C1L

C1=−1/24wL3

Therefore,

EIy=1/12wLx3

−1/24wx4

−1/24wL3

x

Maximum deflection will occur at x = ½ L (mid span)

EIymax=1/12wL(1/2L)3

−1/24w (1/2L)4

−1/24wL3

(1/2L)

EIymax=1/96wL4

−1/384wL4

−1/48wL4

EIymax=−5/384wL4

δmax= 5wL4

/384EI

Taking W = wL:

δmax=5(wL)(L3

)/384EI

δmax=5WL3

/384EI

(c)

∑Fx= 20 +25cos60+15cos70 - 20cos30 - 10cos 45

= 13.24kN

∑Fy = 25sin60 + 10sin45 - 20sin30 – 15 sin75

= 4.63kN

Resultant R= √ (∑Fx2

+ ∑Fy2

)

24

=14.03kN

Tan θ = 4.63/13.24

=0.3497

=19.27o

Therefore the equilibrant, E = -14.03