s
School of the Environment
Semester 2 Examinations 2006-2007
BE136
Materials & Structural Behaviour
Instructions to Candidates:
Time allowed: THREE hours
Student number
Seat location
Instructions:
Answer ALL questions in this paper
Answer ALL questions in SECTION 1
Answer ALL questions in SECTION 2
All answers are to be written on the exam paper
Additional pages may be attached to this answer book
Monday 4 June 2007, 9:00-12:00hours
BE136 Materials & Structural Behaviour
SECTION 1
total volume
Question 1:
VA
VS
A
B
E
C
F
D
G
water
content
Place the letters corresponding to the following consistencies and consistency
limits into the table below as indicated in the figure:
Liquid limit
Semi-solid
Plastic limit
Liquid
Plastic
Shrinkage limit
Solid
(7 marks)
Page 2 of 24
Section A
BE136 Materials & Structural Behaviour
Question 2:
Multiple choice – please circle the letter of the correct answer
1. Which of the following rocks is most likely the strongest?
(a) Sandstone
(b) Marble
(c) Granite
(d) Limestone
2. The two most common elements in the earth’s crust are:
(a) Silica and aluminium
(b) Calcium and silica
(c) Oxygen and Silica
(d) Iron and Oxygen
3. Igneous rocks are generally:
(a) soft
(b) layered
(c) dark grey
(d) very hard
4. Which mineral is most likely to give soil a brown – red colour?
(a) Calcite
(b) Iron oxide
(c) Quartz
(d) Rock salt
5. Landslides are most likely to be caused by:
(a) high winds
(b) excess of pore water pressure
(c) hot temperatures
(d) burrowing animals
6. A load of 5 kN on an area of 0.2 m2 equals a stress of:
(a) 2500 N/m2
(b) 2.5 kPa
(c) 10 kN/m2
(d) 25 kN/m2
(6 marks)
Page 3 of 24
Section A
BE136 Materials & Structural Behaviour
Question 3:
Indicate true or false to each of the following statements by circling “T” or “F”:
a)
Loess soils are classified as glacial till
T
F
b)
Peat soil contains large amounts of organic material.
T
F
c)
Glacial till is characterised by a large range of particle sizes.
T
F
d)
A quick clay has an undisturbed stregth much less than its
remoulded or disturbed strength.
T
F
e)
A Rock mass is generally stronger than a small rock sample
of the same material.
T
F
f)
The plastic limit of a soil is measured by rolling a 3mm thread.
T
F
g)
The cohesion model is applied to coarse grained soils.
T
F
h)
Drainage is very important for slope stability.
T
F
(8 marks)
Question 4:
sort the following rocks and minerals into the table below:
Granite, quartz, sandstone, basalt, mudstone, calcite, gneiss, mica,
conglomerate, marble, siltstone, schist, limestone, feldspar, chalk, breccia
Mineral
Igneous rock
Sedimentary rock
Metamorphic rock
(8 marks)
Page 4 of 24
Section A
BE136 Materials & Structural Behaviour
Question 5:
Sensitivity of a soil is defined as the ratio of the in-situ strength by the
remoulded strength (S = in-situ strength / remoulded strength).
Indicate which of these soils have high values of sensitivity S
dense sand
Quick clay
Glacial till
Loess
loose sand
(3 marks)
Question 6:
Identify the grain shapes depicted below:
A
B
C
D
angular
flaky
subangular
rounded
(4 marks)
Page 5 of 24
Section A
BE136 Materials & Structural Behaviour
Question 7:
A block with weight W = 50 kN rests on a slope with the angle  = 30.
Determine:
-
the normal force FN applied by the block onto the slope surface
-
the shear force FS applied by the block onto the slope surface
-
the shear resistance R if the angle of friction between the block and the
slope is  = 35.
-
the factor of safety of the block for  = 30° and  = 35°
-
the factor of safety of the slope angle is increased by 10
FN
FS
R

FoS
W
FoS (increased
slope angle)
(10 marks)
Page 6 of 24
Section A
BE136 Materials & Structural Behaviour
Question 8:
The results of a dry-sieving test are given below. Complete the table and plot
the grading curve on the semi-logarithmic graph.
Sieve mesh
Mass
Percentage
Percentage
size (mm) retained (g)
retained
finer (passing)
63
37.5
20
10
6.3
3.35
2.0
1.18
0.6
0.4
0.3
0.15
0.063
Pan
TOTAL
32.7
3.6
29.1
75.0
21.4
11.2
27.1
41.3
108.7
53.6
10.7
11.7
2.6
81.6
510.3
Grain Size Distribution
100
90
Cumulative Passing %
80
70
60
50
40
30
20
10
0
-10
Clay
Silt
0.002 0.006 0.02
Sand
0.06
0.2
0.6
2
Grain Size (mm)
Gravel
6
20
Cobbles Boulders
60
200
600
(18 marks)
Page 7 of 24
Section A
BE136 Materials & Structural Behaviour
Question 9:
Using the relationships in the diagram below, calculate:
Mass
Volume
Air
VA
Water
VW
Proportions
e
VV
MW
MS = GS * W
W =
103
Solid
VS
V
1+e
1
VS
kg/m3
Moisture content = MW / Ms
n = VV / V
e = Vv / VS
Sr = VW / VV
Proportions:
n = e / (1 + e)
e = n / (1 – n)
v = 1 / (1 – n)
v=e/n
g = 9.81 m/s2
Density of water = 1000 kg/m3
A moist soil sample has a mass of 3.62 kg and a volume of
1.75 * 10-3 m3. After drying in an oven the sample has a mass of 3.15 kg.
Determine the following:
Density of moist sample
Unit weight of moist sample
Density of dry sample
Moisture content of the sample
Volume of water in the sample
A fully saturated soil sample has a moisture content of 25%; the volume
of the soil grains is 2.0*10-3 m3; the mass of the soil grains is 5.34 kg .
Determine the following:
The density of solids in the sample
The mass of the water in the sample
The total volume of the sample
The void ratio of the sample
(18 marks)
Page 8 of 24
Section B
BE136 Materials & Structural Behaviour
Question 10:
A house is built in the south-east of England on a site with several large trees
as indicated in the plan below. (Extracts from the NHBC standards “Building
near trees” are provided)
Weeping Willow
Plum
12 m
5m
15 m
10.5 m
Ash
9m
During site investigation it was found that the soil conditions at the site are a
clay soil with a high shrinkage potential. Consider the location of the building
with respect to the trees to determine the acceptable depth for the house
foundations.
Answer:
(18 marks)
Page 9 of 24
BE136 Materials & Structural Behaviour
Extracts from NHBC Standards “Building near trees”
Page 10 of 24
BE136 Materials & Structural Behaviour
Extracts from NHBC Standards “Building near trees”
Page 11 of 24
BE136 Materials & Structural Behaviour
SECTION 2: Answer all questions
Question 1
What is the valence number of Magnesium and Chlorine with an electron shell
configuration of:
Mg:
1s 2 2s 2 2 p 6 3s 2
A
+3
B
-2
C
+2
Cl:
A
+5
B
-1
Answer
1s 2 2s 2 2 p 6 3s 2 3 p 5
C
-5
Answer
(4 marks)
Question 2
Are the following statements true or false (tick the relevant box).
TRUE
1
The atom exists in its most stable
configuration when its outermost shell
is completely filled with electrons
2
The valence of an atom is determined
by the total number of electrons in the
atom
3
If an atom has a valence of zero the
atom is unstable
4
Ionic bonding occurs between two
dissimilar atoms
FALSE
(4 marks)
Page 12 of 24
BE136 Materials & Structural Behaviour
Question 3
A block of material has a volume of 1.5 cubic metres and a weight of 10 kN,
what is the density of the material in kg/m3?
A
679.5
B
1200
C
849.5
D
120
(4 marks)
Question 4
What is the total load (in Newtons) that can be suspended from a steel wire of
2.5 mm in diameter? The ultimate tensile strength of the steel is 265 MPa.
A
687.5
B
1045.5
C
1301
D
1650
(4 marks)
Question 5
A 5000 mm long wire suspends a weight of 2000 kN and is stretched by 5
mm. What is the strain in the wire in percent (%)?
0.1
A
0.4
B
2.5
C
Answer
(3 marks)
Page 13 of 24
BE136 Materials & Structural Behaviour
Question 6:
The figure below shows a typical stress-strain curve for a metal alloy. From
the curve match the points A, B, C and D with the descriptions below.
Tensile strength
Linear elastic region
Breaking or ultimate strength
Yield point
Stress
C
Tensile strength
Yield
B
strength
Breaking
D
strength
= Modulus of elasticity
A
Strain
(4 marks)
Page 14 of 24
BE136 Materials & Structural Behaviour
Question 7
Indicate (tick box) if the following statements are true or false
True
False
The strength of concrete increases if the water: cement
ratio increases (i.e. more water is added)
The workability of a concrete is proportional to the free
water content
Hydration of concrete is an exothermic process
The strength of concrete increases with time
(4 marks)
Question 8
What are the two prime ingredients used in the manufacture of Portland
Cement
1
2
(4 marks)
Question 9
List four items that control the quality of concrete
1
2
3
4
(4 marks)
Page 15 of 24
BE136 Materials & Structural Behaviour
Question 10
Match the tests to the property they measure
A: Slump test
B: Cylinder splitting test C: Cube crushing test
Compressive strength
Workability
Tensile strength
(3 marks)
Question 11
The strength of hardened concrete is measured at
A
B
C
14 days
7 days
28 days
Answer
(2 marks)
Question 12
Indicate if the statements below are true or false
True
False
In timber, the moisture content at which the cell wall is
saturated with bound water and at which no free water is
present is called the fiber saturation point, (FSP).
The FSP varies from species to species, but it averages
about 28% moisture content
Addition or removal of water below the FSP has no
pronounced effect on the wood properties
(3 marks)
Page 16 of 24
BE136 Materials & Structural Behaviour
Question 13
Which of the following is the strongest directions of a tree
A
B
C
Longitudinal
Radial
Tangential
Answer
(2 marks)
Question 14
What is the moisture content in percent (%) of a piece of wood if its wet
weight is 125 grammes and its oven dried weight is 100 grammes?
A
B
C
2.5
25
12.5
(3 marks)
Question 15
What do the terms ‘OSB’ , ‘LVL’ and PSL stand for ?
OSB
LVL
PSL
(3 marks)
Page 17 of 24
BE136 Materials & Structural Behaviour
Question 16
Identify the manufactured timber products depicted below
A
B
C
D
OSB
GULAM
Particleboard
PSL
(4 marks)
Question 17:
List three advantages of manufactured timber products over that of natural
timber
1
2
3
(3 marks)
Page 18 of 24
BE136 Materials & Structural Behaviour
Question 18
Match the following definitions to the terms
Ductility
Resilience
Toughness
A
The capacity to adsorb energy elastically
B
The ability to adsorb energy up to fracture
C
The ability to deform before breaking
(3 marks)
Question 19
List TWO methods for combating the corrosion of mild steel:
1
2
(2 marks)
Question 20
Match the carbon content to the metal listed
Carbon
content (%)
Metal
<0.25
A
Cast iron
2-4 %
B
Structural steel
0.25 - 2 %
C
Carbon steel
(3 marks)
Page 19 of 24
BE136 Materials & Structural Behaviour
Question 21
Are the following statements true or false (tick the relevant box)
TRUE
1
Galvanic corrosion occurs when
similar metals are in contact
2
Brass is an alloy of copper and zinc
3
Phosphor bronze is an alloy of bronze
and brass
FALSE
(3 marks)
Question 22
What do the following terms stand for ?
PVC
HDPE
GRP
(3 marks)
Question 23
Identify (i.e. circle) the natural polymers in the list below
cotton, leather, silk, proteins, enzymes, starches, cellulose, Teflon, polypropylene,
Nylon, polystyrene, rubber (latex), concrete, quartz
(5 marks)
Question 24
Give three examples of composite materials used in construction
1
2
3
(3 marks)
Page 20 of 24
BE136 Materials & Structural Behaviour
Question 25
Are the following statements true or false (tick the relevant box)
TRUE
FALSE
Concrete is stronger in compression than in
tension
A material which does deform before failure is
termed 'ductile'
The ability of a material to absorb elastic energy
is termed 'toughness'
A 'brittle' material has a small area under the
stress strain curve
Timber only shrinks once the moisture content
is above the fibre saturation point
Polymers with more than one type of 'mer' are
termed 'copolymer'
Polymers are very stiff
Polymers creep excessively under load
(8 marks)
Page 21 of 24
BE136 Materials & Structural Behaviour
Question 26
Draw a typical load deformation response up to failure for a timber and
concrete beam loaded by a point load at the mid-span as indicated in the
figure. Identify the typical phases of the beam responses.
Load
deflection
(4 marks)
Page 22 of 24
BE136 Materials & Structural Behaviour
Question 27
For the following loading and support configurations, indicate on each drawing
where you would place the TENSION reinforcement if the beams are to be
fabricated from reinforced concrete (do not consider any self-weight effects).
(8 marks)
Page 23 of 24
BE136 Materials & Structural Behaviour
Aide memoire
Acceleration due to gravity = 9.81 m/s/s
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Page 24 of 24
3
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