ABSTRACT
The work has gone a long
way in determining strength of concrete made of various aggregates such as
granites stone, black gravel, washed gravel and surface gravel.
Some factors such as
porosity of the aggregate temperature coursing lose of water plate form
for mixing of concrete mix affect the workability and eventually the strength
of concrete.
This project work
consist of using hydraulic machine to carryout the compressive test of the
strength of concrete made of the earlier mentioned aggregated.
From the result obtain,
it is quite clear that their strength are not the same,
The result also reflect
the strength of aggregate since their strength can be directly
determined.
The finishing from these
works show the strength of these aggregates and also reflect the standard of
work that these aggregate can be used for concreting.
TABLE OF CONTENT
CHAPTER
ONE
1.1
Introduction
1.2
Project
objective
1.3
Particle sized
distribution
CHAPTER
TWO
2.1
Concreting
2.2
Testing of
cubes
CHAPTER
THREE
3.1
Discussion of
result
3.2
Result
3.3
Conclusion and
recommendation
Bibliography
CHAPTER ONE
RETAINING WALLS
Retaining walls are
structures used in providing stability for earth or materials where conditions
do not give room for the material to assume its natural slope and are mostly
used to hold back soil banks, coal or over, piles and water.
Retaining walls are
distinguished from aone another based on the method of achieving stability.
There are six type of
retaining walls and are:
i. The
gravity wall
ii. The
cantilever wall
iii. The
counterfort retaining wall
iv. Buttressed
retaining wall
v. The
crib walls
vi. Semigravity
wall
Bridge abutments are
often retaining walls with using wall extension to retain the approach fill and
provide protection against erosion. They differ in two major respect from the
usual retaining walls.
i. They
carry and reactions from the bridge span.
ii. They
are restrained at the top so that on active earth pressure is unlikely to
develop.
Foundation walls of
building mduding residential construction and retaining walls, whose function
is to contain the earth of the basement.
Retaining walls are
required to be of adequate proportion to resist over turning and sliding as
wall as being structurally a proportion to resist over turning and
sliding as wall as being structurally adequate.
Terms used in retaining
wall design are shown below (f.g 12).The toe is both the front base perfection
and forward edge, similarly for the heel the backward perfection.
Fig(11)
The different types
representation diagrams of retaining walls are shown in fig (12) below.





















a) Gravity walls of stone masony, brick, or
plain concrete






























The retaining wall as a
whole must satisfy two basic conditions. They are
i. The
base pressure as the toe of the wall must not exceed the allowable bearing
capacity of the soil.
ii. The
factor of safety against sliding between the are and the underlying soil must
be adequate a value of at least usually being specified. (Rit Craig 2^{nd} edition
soil mechanical published by van nostrand rain hold co.ltd)
Retaining wall design goes on with the
choosing of tentative dimensions, which are then analyzed for stability and
structural requirements. Since this s a trail process overall solution to
the problem may be obtained, all of which are satisfactory.
CANTILEVER RETAINING
WALL
The cantilever wall is a
reinforced concrete wall that utilizes cantilever action to retain step. The
mass behind the wall from assuming natural slope. Stability of this wall mainly
depends on the mass of the soil on the heel behind the wall.
Dimensions for a retaining
wall should be adequate for structural stability and to satisfy local building
code requirement.
The date shown below may
be used where no other data is available but may result in a overly
conservative design. The 200mm from a liberal interpretation. of act
(1966) and preferably not less than 600mm so that the proper placement concrete
off or is broke off a sufficient amount will remain to satisfy structural and
aesthetic require (Bowles I . E)
The base slab
dimension should be such that the resultant of the vertical loads fall
within the middle one third otherwise. The toe pressure will be too much such
that only a part (Bowles JE and (Hansen and Peck) of the footing will be
effective.
A better is
increasing in order to save materials. A front better is more acceptable so
that the forward wall movement to develop active pressure is not noticeable.
A slight increase in
wall stability is usually obtain when the battler is on the Bach face
(Ref Bowles J.E) see fig 13 below for illustration.












RANKING THEORY
Ranking theory deals
with pressure within a soil mass under the following condition (ie assumptions)
i. The
wall is vertical
ii. The
retaining wall face is smooth
iii. The
wall yield above the base and satisfies the condition of plastic equilibrium
iv. It
is isotropic
Ranking theory applies when the soil mass
is in so called rankling sate.
When a soil mass is
allowed to explain (active earth pressure) or contract (passive earth pressure
rapture surface will form within the mass. if not interrupted by the back of
the retaining wall or other strictures, the mature surface will be aeries of
straight lines making an angle 1 with the horizontal.
Active earth pressure i = 45 + Ø/2
Passive earth pressure i = 45 – Ø /2
When the state above exists, the soil is said to
be in the Rankin state and the Rankin theory is applicable.
Where pa and pp = unit
active and passive earth pressure respectively, at a depth Z
q= vertical pressure or load due to the
weight of the soil above Z
C = cohesion strength of the soil
Ka and kp – coefficient of active and passive
earth pressure respectively
Ka = 1sin Ø, kp =1+ sine Ø :.
1x sinØ
1 sinØ
According to ranking
theory, earth pressure increase linearly with the depth of the same manner as
the lateral pressure exerted by a fluid. For the reason engineers often refer
earth pressure as equivalent fluid pressure.
For a cohesion less soil
Pa =1/2 ka rH^{2} and
Pp = ½ rH^{2}
When the back of the wall is inclined
Ka = cos B CosB√CosB – Cos Ø^{2}
CosB_√CosB  Cos Ø^{2}
^{ }
^{ }
^{ }

Ka =
1/kp
(Ref Civil Engineering
and Engineering machines series by (ref Civil Engineering and Engineering
machines series b Newmark & W.J. Hall)
FORCES ON A CANTILEVER
RETAINING WALL
Due to the difficulty in
getting or calculating the wall frication, Rankin active pressure is normally
used (ie O=o) mainly for walls less than 6 to 7 matters in heights
It is more
economical to use the coulombs equation for walls over 7m in height. It
should also be clear that it is not the height it used for
computation if max. Shear and bending moment that is used for sliding
computation to get the driving force. It is left for the design to decide
whether to use passive pressure from the soil in front of the toe and whether
the soil covering the top portion will be available for existing over
turning moment and sliding. Sometimes this is not considered. Just for
conservative purpose
The triangular pressure
diagram on the stem,wil yield a shear diagram that is a third degree
curve.
The use of the different
equations for shear and moment seems to be easier.
This enables the
roped computation of the cut off points for there in forcing steel since it is
uneconomical to use a constant amount of reinforcement for the entire wall
height.
From the diagram shown
below. The with of the base slab is deduced from the gross. Soil pressure
diagram before computing the shear and moments diagrams. The
eccentricity of computed by equation (iii) and (iv) shown below.
Differential equations
can also be used to compute the shear and moments of the base slab if the safe
of the cane is desired and even when numerical values are required.
Fig 14 shows these illustrations diagrammatically
Forces on cantilever
wall (a) entire unit; free bodied for (ii) stem,(ii) toe, (iv) heel. Note that
M_{1}+M_{2}+M_{3} =
Y0
Fig (15)
Cantilever retaining
wall (a) stem shear and moment (b) to and heel shear and moments.
CONTERFORT RETAINING
WALL
Counterfort retaining
wall, are similar to the cantilever retaining wall only that this type
has counterforts built behind to hold the wall (stem) and base together and is
used where the cantilever is long or for very high pressure behind the wall
this counterforts behinds the wall are subjected to tensile forces.
The dimension indicated
in the diagram below, only act as a guide, some walls which are about 100mm to
150mm thick have been built in area like united Kingdom. Any thickness which
satisfies stability of the wall can be used.
Relative costs of forms,
concrete, enforcement and labour will determine to use of counterfort but it is
doubtful if a counterfor wall will provide any relative
construction economy values it is over 7m is height.
The spacing in the
counterforts is based on the trail and error in other to huiumise
cost. The most economical method is placing them 1/3 to ½ H (height) apart. by
conventional beam theory bending moments in the face slab cantilevered part of
the wall as at the interior if the length of over hang is made 0.411 and
a spacing between counterforts of L.

The
counterfort will may be constructed with out a toe if additional front
clearance is needed and sliding and overturning stability requirements are met.
Design dimension for a
counterfort wall
FORCES ON A COUNTERFORT
WALLS
Counterfort walls are
described as indeterminate problem. this can be solved by the use of plate
theory of the expense of large amount of labour. Simplified methods are
commonly used in the solving of this problem which makes it to be overdesigned
the weight of the counterfort is not considered in the design.
A simplified and
conservative solution to a counterfort wall problem is in the diagram shown
below (gig 17). The face slab of the wall is considered as continuous slab
constituting series of equivalent unit –width beam since the pressure
distribution is triangular, the equivalent beam should be analyzed for strips
at the junction of the wall and base and at two or three intermediate location
between the top of the wall and base so that adjunctions in reinforcing
steel can be made as the pressure decrease moment distribution can be used to
find the bending moment, although due to approximations being made continuous
beam coefficients maybe used for lower strip wh2/12 or wl2/14may be used
because of the lower edge being fastened to the base while for the upper
strips, wl2/9 or wl2/10 can be used for a conservative solution or method. The
same coefficients for both positive and negative moments maybe employed as the
designer consider appropriate the toe of the base is considered as a
cantilever beam and heel as a continuous beam, similar to the treatment of
the shrinkage steel should be satisfied in the directions not steel
should be satisfied in the directions not analysed in this manner the
counterfort member may be considered as a wedge shaped Tbeam, which include
the applicable portion of the wall tem as the flange, bat these beams are so
massive that the concrete stresses will be so low that an analysis is usually
not required. Tensile steel will be required at junction of the base (heel) and
the counterfort to resist the moment, fending to tip the wall over and the
quantity can be conservatively computed treating the conuterfort along as a
beam. Tensile steel will also be required running horizontal from the
counerfort into the stem to tie the wall and counterfort together. in some
case, the bound stress requirements of this reinforcement control the slope of
the counerfiort member.
Huntington (1957) presented a method in the diagram below. the also recommended
a value for one in the middle half of the wall, at the base of
0.2qH to be used as long as he ratio of counterfort spacing to the wall
height L/H > 0.5 BOWLES J.E 1982.















































qL^{2}/10 for
top strips for stem with an average ‘q’ on unit strip
qL^{2}/10 for
top strips near the bottom of stem because of fixity of stem to base.
qL^{2}/10
for all strips in the heel use an average net q for heel pressure.
consider both rH and the upward actins soil press.
Fig 17, reduction of
the complex analysis of a counterrfort RW to a system of simple beans for
rapid design.












Computation of bending
moment in horizontal direction for the counterfort stem (Huntington 1957)
qs = Ws + Wcb
b
qb = Pa sin B
b
q^{1}b = Pb^{1} sin
B
b
q=W^{1}_ qs
+qb+q^{1}b
qnet =qs+q^{2}b+qb+W^{11}4
NOTE: The increase in
heel pressure due to moment is
W ^{1}=2.4m:
W1 = W^{1 } = 2/3W^{1}b
6
MT == toe moments value
at front face of wall.
Note that W^{1} is
parabolic but may be approximated as a uniform pressure W^{11}
W^{11} =w1/b
Assure pressure q^{1}b,
qb and q are constant and uniformly distributed across b
If BO the is only q and
will W^{1} to consider since W11 qb and q^{1}bare small he
design will usually be sufficiently accurately to neglect these pressure
THE GRAVITY RETAINING
WALL
This type of wall
depends on its weight in other to achieve stability, just as the name implies.
it also depends used in the constriction
No reinforcement is
provided except in concrete walls where a nominal amount of steel is placed
near the exposed faces to prevent surface cracking due to temperature changes
(shrinkage)












Typical dimension for
gravity walls maybe taken as shown below. Generally, gravity walls have
trepezodial shape but it can also be constructed with broken backs. The base
and other dimensions are designed and constant in such a way that the resultant
falls within the middle on third of the base. The top width of the stem should
be on the order of 0,30m. if the heel perfection is only 100 to 150mm, the
coulomb equation may be used for evaluating the lateral earth pressure, with
the surface of sliding taken along the back face of the wall. The Rankin
solution may face of used on a section taken through the heel. Due to the
massive proportions and resulting low concrete stress, low strength concrete
can generally be used for the wall construction.
A critical section for analysis of tensile flexure stress will occur, through
the junction of the toe portion at the front face of the wall.












i. Tentative
dimensions for a gravity retaining wall
ii. Broken
–back retaining wall
FORCES ON GRAVITY
RETAINING WALL
The active earth pressure is computed by using either the rackine or coulomb
methods if the coulombs method is used it is assured that there is
incipient sliding on the back face of the wall, and the earth pressure
acts at the angle of wall frication to a normal with the wall. The rackine
solution applies to Pa acting at the angle B on a vertical plane through the
heel.the vector can then be added to the weight vector of the edge of
magnitude of the resultant Pa and the wall. The vertical resultant R acting on
the base is equal to the sum of the forces acting downward, and will have an
eccentricity e with respect to the geometrical center of the base
Taking moments about the
toe
x = sum of overturning moment
R
If the width of the base
is B1, the eccentricity of the base can then be computed as
e = B x
Z
a.
coulomb analysis Ph =Pa cos B
b.
Rankin analysis Pv =Pa sinB
SEMI GRAVITY WALLS
Semi gravity walls are intermediate between a
true gravity and a cantilever wall. It is somewhat more slender than a gravity
wall and requires reinforcement consisting of vertical bars along the
liner face and dowels continuing into footing. H likewise is provided with
temperature steel war the exposed face to prevent shrinkage or expansion and contraction
of wall due to temperature changes
Department  Civil Engineering 
Project ID Code  CVE0010 
Chapters  5 Chapters 
No of Pages  68 pages 
Reference  YES 
Format  Microsoft Word 
Price  ₦4000, $15 


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