Download - Training Report_khasa Kothi
-
8/2/2019 Training Report_khasa Kothi
1/33
JAIPUR DEVELOPMENT AUTHORITY
TRAINING REPORT
ON
KHASA KOTHI FLYOVER
Submitted by:
-
8/2/2019 Training Report_khasa Kothi
2/33
JDA at a Glance
Strengthening Faith: Jaipur Development Authority
Jaipur Development Authority (JDA) has been committed to workingfor the benefit of the citizens of Jaipur with planned implementation
of development schemes and is consistently striving to take Jaipur at
higher levels of progress. Jaipur is one of the most well-planned
cities of its times and planned development has always been central
to its ideology.
Jaipur Development Authority came into existence by the
Government of Rajasthan with a vision to combat and manoeuvre
the growing requirements of a large city in wake of the increasing
population and to help give Jaipur a planned look compatible and
comparable to any metropolitan city of repute. JDA was authorised
powers and a green signal to speed up the development and
progressive growth of the entire city to rapidly change the face of
Jaipur. To meet these important needs JDA sprang into action and
started to understand the necessary needs of the city.
According to the requisites, JDA has been working towards time-bound construction, creation and development of the western part of
Jaipur based on major scientific and hi-tech strategies. Thus, Jaipur
has been beautified intensively to augment the tourist attraction in
the city and to raise the living standards to suit convenience of its
citizens.
The major undertaking of JDA includes the following:
* Infrastructural development of Jaipur region by construction of
flyovers, bridges, parking places.
* Development of commercial projects and residential schemes,
etc.
* Development of basic amenities like community centres, parks,
ring roads.
* Development and rehabilitation of kacchi bastis etc.
-
8/2/2019 Training Report_khasa Kothi
3/33
* Preparation and implementation of master plan.
* Preparation and implementation of guidelines for colonisation.
* Environmental development by planning and implementing
roadside plantations and by developing eco-friendly schemes.
* Development of rural area around Jaipur.
* Development of transport facilities like Mass Rapid
* Transport System (MRTS), Transport Nagar, and major sector
roads.
According to the promises and commitments of the Rajasthan
Government, JDA has been time and again proving itself as a pioneer
of development, creating a state-of-the-art city of substance. JDA
has been working on widening all main roads, construction of over
bridges, under bridges and flyovers to regulate the traffic on roads,
minimize pollution, and ensure public convenience and safety. JDA
firmly believes in bridging the gap and reaching out to its citizens
and to provide them with quick and hassle-free service.
JDA...where town planning is a tradition.
-
8/2/2019 Training Report_khasa Kothi
4/33
Contents
1. Introduction
2. Components of flyover
i) Foundation
ii) Piers and abutments
iii) Deck
iv) Pre-stressed concrete
v) Backfill and Reinforced earth wall
3. Test reports
-
8/2/2019 Training Report_khasa Kothi
5/33
KHASA KOTHI FLYOVER
INTRODUCTION
The Khasa Kothi flyover is being constructed at one of the busiest
traffic junction in jaipur city. The flyover is being constructed on the
road connecting the railway station to Sindhi Camp bus stand to
facilitate the easy movement of traffic plying from station to Chandpole, M.I. road & Banipark area. The cost of project is Rs. 22.0 Crore
and length of fly over 740.0 Mts.
The work was commenced after the stone laying on 30.10.06. The
work was stopped due to order passed by Honble high court on
8.2.07 for maintaining status quo. This order was declared non
operative by Honble high court on 30.05.07 and work restarted
thereafter.
The work worth Rs. 6.50 Crore has been done by 20th April 2009. The
super structure work is in progress and 80% of reinforced earth wall
panel has been casted. The work is proposed to be completed by
August 2009.
Salient Features
Project Cost : Rs. 2200.00 Lacs
Agency : M/s Harish Chandra (I) Ltd.
Consultant : Span Consultant Pvt Ltd.,
Delhi
Work order amount : Rs.19,63,69,312.00
Stipulated date of commencement : 15.04.2006
-
8/2/2019 Training Report_khasa Kothi
6/33
Stipulated date of completion : 14.10.2007
Work Period : 18 Months
Date of Start : 30.10.2006
Physical Features
Total Length : 740 Mts.
Total Width : 16.75 Mts.
Width of Roads : 2 X 7.5 Mts. (2 lanes each)
Median Width : 1.00 Mts.
Via Duct Length : 455 Mts.
Approaches : 285 Mts.
Nos. of Spans : 14
Service Roads : 5.5 Mts. On either side
The grade of concrete used in the construction is M-50.
-
8/2/2019 Training Report_khasa Kothi
7/33
SOME IMPORTANT THINGS!!!
1) Always wear a good quality helmet on the
site.
2) Always wear shoes on the site.
3) Wear safety belts if required.
4) Safety nets should be provided wherever it is
necessary.
-
8/2/2019 Training Report_khasa Kothi
8/33
MAJOR COMPONENTS OF FLYOVER
FOUNDATION
Since the bridge has to carry a big live load and its dead weight is
also very large so we cannot go for simple foundation but pile
foundation.
Pile foundation is one type of deep foundation. It is used where the
good soil is at higher depth (10 or 15m) or soil having low bearing
capacity. Pile is also used for tall structures. In pile foundation the
load coming from the super structure is taken by pile cap and
equally distributed in no of piles, pile transfers this load into the soil.
The Khasa Kothi flyover consists of 115 bored cast in situ piles with
14 pile caps.
The diameter of each pile is 1200 mm with depth 25 meters and
different piers have different set of group of piles.
Pile group under A1,P2,P3,P11,P12 and A2
-
8/2/2019 Training Report_khasa Kothi
9/33
Pile group under P1,P4,P10 and P13 Pile group under
P8
Pile group under P5,P6 and P9 Pile group under P7
A1 and A2 are Abutment 1 and 2; P1,P2,P3.. are Pier no 1,2,3..
The depth of pile cap is 2 m which is 500 mm below ground level.
-
8/2/2019 Training Report_khasa Kothi
10/33
INSTALLATION PROCEDURE OF PILES
Step 1 --- Excavation of Pile Shaft
The bored pile equipment set including hydraulic oscillator, hydraulic
vibrator, hammer grab and rock chisel used in this project is very
common and being widely used for shaft excavation.
a. Set out the correct position of the bored pile on site.
b. Excavate about 3 - 4m of the pile to remove shallow
obstructions and then backfill, wherever necessary.
c. Install the bottom section of temporary casing of required
diameter into the ground by oscillating and jacking or byvibrating motion exerted by the oscillator and the vibrator
respectively.
d. Set up hydraulic oscillator or vibrator in conjunction with a
crawler crane.
e. Excavate within the casing by hammer grab and redrive the
steel casing simultaneously by using the heavy duty casing
oscillator / vibrator. Rock chisel in various types will beemployed for removal of obstruction or hard materials during
the above process.
f. Extend the steel casing by bolting or welding on additional
casing during the excavation.
g. Water will be pumped into the casing during excavation and
constant water head will be maintained so as to prevent any
ingress of material from the bottom of casing.
h. Verticality of the casing will be monitored by means of spirit
level from time to time.
i. Continue the above procedure until the founding level of pile
has been reached .
j. Pile base enlargement will be formed by employing a bellout
chisel or a reverse-circulation drill as indicated in the workingdrawings.
-
8/2/2019 Training Report_khasa Kothi
11/33
Step 2 --- Cleaning of Pile Shaft
Final cleaning will be carried out by the air-fitting method using high
pressure air compressors. The slime and muddy water within the
casing will be cleared and delivered into a desilting tank before
discharge.
Step 3 --- Tremie Concreting
a. The pile shaft will be concreted by "Underwater Tremie
Technique". The tremie pipe sections will be inserted and be
jointed until it reaches the bottom of pile shaft. Concrete will be
poured into the tremie pipe by using a concrete skip.
Concreting will be carried out in one continuous operation until
the required level has been reached.
b. As concreting proceeds, the level of the concrete relative to theground level will be monitored by measuring with weighted
tape after each skip of concrete is placed.
c. The base of the tremie pipe will be kept with a minimum depth
of approximate 1 to 2m below the surface of the concrete.
d. The temporary casing will be extracted simultaneously by the
oscillator in the course of concreting. A head is always
maintained between the top of concrete and the bottom ofsteel casing.
-
8/2/2019 Training Report_khasa Kothi
12/33
Step 4 --- Installation of Reinforcement
After the completion of concreting, dowel bars of required length
and numbers will be installed into the pile shaft and down to the
predetermined level before the extraction of bottom steel casing.
PIERS & ABUTMENTS
The Khasa Kothi flyover has 15 piers including two abutments.
The maximum height of the pier is about 6 m.
http://www.cse.polyu.edu.hk/~ctpile/insta/i-bpile/i-tc1.jpg -
8/2/2019 Training Report_khasa Kothi
13/33
A typical Expansion joint used in bridge
DECK
The Khasa Kothi bridge is of box girder type bridge which is
comprised of prestressed concrete. The box is typically of
trapezoidal in cross-section. Compared to I-beam girders , box
girders have a number of key advantages and disadvantages.
Box girders offer better resistance to torsion, which isparticularly of benefit as the bridge deck is curved in plan.
-
8/2/2019 Training Report_khasa Kothi
14/33
Additionally, larger girders can be constructed, because thepresence of two webs allows wider and hence stronger flanges
to be used. This in turn allows longer spans.
On the other hand, box girders are more expensive to fabricate,and they are more difficult to maintain, because of the need for
access to a confined space inside the box.
The span length is of range of 25 m to 50 m.
The box girders are made of concrete and were casted in place
using falsework supports. First 75 m span is of solid type deck and
then it consists of box girders i.e. from A1 to P3 and P11 to A2 the
deck is solid with the depth 1.2 m.
The depth of box girder is different as per load requirement. From P3
to P6 and P9 to P11 it is 2.2 m and from P6 to P9 it is 2.5 m.
The slope of the deck is 1 in 29 m. The total width of the deck is
16.75 m including 1m wide median and two crash barrier of width
0.375 m.
-
8/2/2019 Training Report_khasa Kothi
15/33
Reinforcement pattern for box girder.
Pre-stressed Concrete
The technique of pre-stressing eliminates cracking of concrete under
all stages of loading and enables the entire section to take part in
-
8/2/2019 Training Report_khasa Kothi
16/33
resisting moments. As dead load moments are neutralized and the
shear stresses are reduced, the sections required are much smaller
than in reinforced concrete.
Prestressing can be accomplished in three ways: pre-tensionedconcrete, and bonded or unbonded post-tensioned concrete.
Pre-tensioned concrete
Pre-tensioned concrete is cast around already tensioned tendons.
This method produces a good bond between the tendon and
concrete, which both protects the tendon from corrosion and allows
for direct transfer of tension. The cured concrete adheres and bonds
to the bars and when the tension is released it is transferred to theconcrete as compression by static friction. However, it requires stout
anchoring points between which the tendon is to be stretched and
the tendons are usually in a straight line. Thus, most pretensioned
concrete elements are prefabricated in a factory and must be
transported to the construction site, which limits their size. Pre-
tensioned elements may be balcony elements, lintels, floor slabs,
beams or foundation piles.
Bonded post-tensioned concrete
Bonded post-tensioned concrete is the descriptive term for a method
of applying compression after pouring concrete and the curing
process (in situ). The concrete is cast around plastic, steel or
aluminium curved duct, to follow the area where otherwise tension
would occur in the concrete element. A set of tendons are fished
through the duct and the concrete is poured. Once the concrete has
hardened, the tendons are tensioned by hydraulic jacks that reactagainst the concrete member itself. When the tendons have
stretched sufficiently, according to the design specifications (see
Hooke's law), they are wedged in position and maintain tension after
the jacks are removed, transferring pressure to the concrete. The
duct is then grouted to protect the tendons from corrosion. This
method is commonly used to create monolithic slabs for house
construction in locations where expansive soils (such as adobe clay)
create problems for the typical perimeter foundation. All stresses
-
8/2/2019 Training Report_khasa Kothi
17/33
from seasonal expansion and contraction of the underlying soil are
taken into the entire tensioned slab, which supports the building
without significant flexure. Post-tensioning is also used in the
construction of various bridges; both after concrete is cured after
support by falsework and by the assembly of prefabricated sections,
as in the segmental bridge.
The advantages of this system over unbonded post-tensioning are:
1. Large reduction in traditional reinforcement requirements as
tendons cannot destress in accidents.
2. Tendons can be easily 'weaved' allowing a more efficient
design approach.
3. Higher ultimate strength due to bond generated between the
strand and concrete.
4. No long term issues with maintaining the integrity of the
anchor/dead end.
Unbonded post-tensioned concrete
Unbonded post-tensioned concrete differs from bonded post-
tensioning by providing each individual cable permanent freedom of
movement relative to the concrete. To achieve this, each individual
tendon is coated with grease (generally lithium based) and covered
by a plastic sheathing formed in an extrusion process. The transfer
of tension to the concrete is achieved by the steel cable acting
against steel anchors embedded in the perimeter of the slab. Themain disadvantage over bonded post-tensioning is the fact
that a cable can destress itself and burst out of the slab if
damaged (such as during repair on the slab).
-
8/2/2019 Training Report_khasa Kothi
18/33
The advantages of this system over bonded post-tensioning are:
1. The ability to individually adjust cables based on poor field
conditions (For example: shifting a group of 4 cables around an
opening by placing 2 to either side).
2. The procedure of post-stress grouting is eliminated.
3. The ability to de-stress the tendons before attempting repair
work.
In Khasa Khothi flyover the method used for pre-stressing is
unbonded post tensioning system. In this system first of all high
tensile steel cables/wires (also known as strands or tendons)
encased in sheathing pipes were laid as per design and then
concreting is done. After the hardening of concrete the stretching of
wires was done by means of hydraulic jacks. The jacking was done
from both ends. The wires were jacked a few percent above their
specified initial pre-stress in order to minimize creep in steel and toreduce frictional loss of pre-stress.
The wires are anchored to concrete after stretching by wedge action
producing a friction grip on wires.
-
8/2/2019 Training Report_khasa Kothi
19/33
Cables left for stressing before concrete is poured
We can see that the cables are in a grouped in every pipe. In the
above picture there are 19 cables in one group.
-
8/2/2019 Training Report_khasa Kothi
20/33
Sheathing pipes carrying cables.
We can see in above picture that the cables are curved as per
design requirement.
-
8/2/2019 Training Report_khasa Kothi
21/33
Stretching of cables by hydraulic jack after hardening of concrete
The jack used in above picture has the capacity to stretch 4 cables
at a time. This jack can perform both operations i.e. stretching of
wire as well as tightening of wedges.
-
8/2/2019 Training Report_khasa Kothi
22/33
Calibrated pressure gauge to read directly the amount of tension
applied
It is however the practice to measure the elongation of steel so that
the magnitude of pre-stress can be calculated independently and
checked against the gauge reading.
-
8/2/2019 Training Report_khasa Kothi
23/33
Covering of cables after grouting
The cables are covered by concrete to prevent corrosion. The
grouting is done through the hole as seen in above picture (in red
circle) and then the hole is then bolted as shown (in blue circle).
-
8/2/2019 Training Report_khasa Kothi
24/33
PROBLEMS LIKELY TO CAUSE DURING OR AFTER CONCRETING
1. Segregation : Segregation of concrete can be defined as
separation of coarse aggregate from mortar, resulting in their
non-uniform distribution. Improper mix proportion resulting in
large proportion of coarse particles as compared to small
proportion of fine particles caused the separation of coarse
particles from mortar. Segregation is also caused by incorrect
handling of mixed concrete during transportation and
placement, and also by over-compaction.
2. Honeycombing : The separation of coarse aggregate frommortar leaves voids in coarse aggregate unfilled and this
phenomenon is called honeycombing. Honeycombing causes
decrease in the density of concrete and hence reduction in the
strength of the concrete.
3. Bleeding : Bleeding is a form of segregation in which water in a
concrete mix rises to the surface during placing it. It is because
more water is present than is necessary for the cement pasteto lubricate the aggregate particles and the solid constituents
of the mix are able to hold all the mixing water when they
settle down. Thus the water rises up and appears on the
surface of the compacted concrete. Sometimes, finer particles
such as cement are also carried with the rising water. The
water trapped by the superimposed concrete results in a
porous weak and the non-durable concrete. If the rising water is
trapped on the underside of reinforcement, then a zone of poorbond is created. This water form voids on evaporation and
makes the concrete weaker.
PRECAUTION TO BE TAKEN DURING PLACING OF CONCRETE:
1. Under no circumstances, the water should be added to the
concrete during its passage from mixer to the formwork
-
8/2/2019 Training Report_khasa Kothi
25/33
2. The formwork or the surface which is to receive the fresh
concrete should be properly cleaned prepared and well-
watered.
3. As far as possible, the concrete should be placed in singlethickness. In case of deep sections, the concrete should be
place in successive horizontal layers and proper care should be
taken to develop enough bonds between successive layers.
4. The concrete should be thoroughly worked around the
reinforcement and tapped in such a way that no honeycombed
surface appears on removal of the formwork.
5. The concrete should be place on the formwork as soon as
possible.
6. During placing, it should be seen that all edges and corners of
concrete surface remain unbroken, sharp and straight in line.
7. The placing of concrete should be carried out uninterrupted
between predetermined construction joints.
CONSOLIDATION OF CONCRETE:
The main aim of consolidation of concrete is to eliminate air bubbles
and thus to give maximum density to the concrete.
In Khasa Kothi flyover the Internal or Immersion vibrators are used
for consolidation of concrete. These vibrators consist of a steel tubewhich is inserted in fresh concrete. This steel tube is called the poker
and it is connected to an electric motor. The poker vibrates while it
is being inserted. The internal vibrators should be inserted and
withdrawn slowly and they should be operated continuously while
they are being withdrawn. Otherwise holes will be formed inside the
concrete.
-
8/2/2019 Training Report_khasa Kothi
26/33
BACKFILL AND REINFORCED EARTH WALL
Reinforced earth is a composite material formed by the friction
between the earth and the reinforcement. By means of friction the
soil transfers to the reinforcement the forces built up in the earth
mass. The reinforcement thus develops tension and the earth
behaves as if it has cohesion. Reinforced members are composed of
thin wide strips also called as ties.
For reinforcement the GI strips are used which are 40 mm wide and
5 mm thick and the length varies as according to the tensile stresses
at various place and levels.
The facing elements for backfill are precast concrete panels having
dimension 1.5m x 1.5m with some aesthetic appearance.
The dry density of the compacted soil was kept 1.85 to 1.9 gm/cc
and the moisture content was kept at 8 to 9%.
Procedure
Place and compact initial lifts of select Granular backfill up to bottom
row of panel tie strips. The level of the compacted backfill should be
50mm above the tie strips. In order to avoid pushing the brace
panels out of alignment, initial lifts of backfill are neither placed nor
compacted against the back of the panels. Compact each backfill lift
using a large smooth-drum vibratory roller except within a 100 cm
-
8/2/2019 Training Report_khasa Kothi
27/33
zone directly behind the panels where a small hand-operated
vibratory compactor must be used to avoid undue panel movement.
After compaction has taken place, check wall alignment visually and
with a level adjust panels as necessary.
A drainage system is made near panels by laying 20mm coarse
aggregates near panels up to a width of 60 cm throughout the depth
and at the bottom a semi perforated pipe is used to drain out the
water.
Immediate gradation and moisture testing is required if either
excessive panel movement or backfill pumping occurs during
construction.
Compaction: Large smooth-drum vibratory rollers are used to
accomplish mass compaction of backfill materials, except for fine
sands.
Sheep foot rollers are never to be used for compaction of backfill.
Fine uniform sands, which contain more than 60 percent passing a425 sieve used for backfill, must be compacted using a smooth
drum static roller.
Vibratory compaction equipment should not be used to compact fine
uniform sands.
Moisture content of backfill material during placement should be
approximately 1% to 2% more than its optimum moisture content.
Reinforcing Strips:-
Place reinforcing strips on the compacted backfill. Position strips
perpendicular to the facing panels, unless otherwise shown on the
plans. Reinforcing strips are supplied in lengths as shown on plans.
Connect each reinforcing strip to the embedded panel tie strip by
inserting the end of the reinforcing strip into the gap between the
two exposed ends of the tie strip. Match the three holes and push a
-
8/2/2019 Training Report_khasa Kothi
28/33
bolt through the holes from below, threading on a nut and
tightening.
Dump backfill onto the reinforcing strips so that the toe of the
backfill pile is 3-4 ft from the panels. Spread the backfill by pushingthe pile parallel to the panels.
Metal tracks of earthmoving equipment must never come in contact
with the reinforcing strips. Rubber-tired vehicles, however, can
operate directly on the exposed strips if backfill conditions permit
and care is exercised.
At the joints of panels a special type of semi permeable textile
known as geo-textile is used to stop the backfill from slipping out ofthe panels.
-
8/2/2019 Training Report_khasa Kothi
29/33
Spreading of backfill
In the above picture we can see the arrangement of panels. No
binding material is used to join the panels they are interlocked with
each other.
-
8/2/2019 Training Report_khasa Kothi
30/33
-
8/2/2019 Training Report_khasa Kothi
31/33
GRADATION FOR COARSE AGGREGATE
TYPE OF AGGREGATE 20mm Date:- 30-05-09
TOTAL WEIGHT TAKEN 2922 Gms
SieveSize
WeightRetained
%Retained
%Cumulative
Retained
%Passing Remarks
25 0 0.00 0.00 100.0020 172 5.89 5.89 94.1110 2662 91.10 96.99 3.01
4.75 68 2.33 99.32 0.68Pan 20
TYPE OF AGGREGATE 10mm Date:- 30-05-09
TOTAL WEIGHT TAKEN 2957 Gms
SieveSize
WeightRetained
%Retained
%Cumulative
Retained
%Passing Remarks
12.5 0 0.00 0.00 100.0010 268 9.06 9.06 90.94
4.75 2514 85.02 94.08 5.922.36 120 4.06 98.14 1.86Pan 55
SieveSize
For 20 mm For 20 mm
Combined
Grading
As per IS 383
%Passing
%Passing
%Passing
%Passing
Lower
LimitUpperLimit
20 100% 63% 100% 37%10 94.11 59.29 100 37.00 96.29 95 100
4.75 3.01 1.90 90.94 33.65 35.54 25 55Pan 0.68 0.43 5.92 2.19 2.62 0 10
-
8/2/2019 Training Report_khasa Kothi
32/33
GRADATION FOR COARSE AGGREGATE
TYPE OF AGGREGATE SAND Date:- 30-05-09
TOTAL WEIGHT TAKEN 531 Gms
Sieve
Size
Weight
Retained
%
Retained
%Cumulati
veRetained
%Passin
g
Remark
s
Zone II
4.75 12 2.26 2.26 97.74 90-100
2.36 28 5.27 7.53 92.47 75-100
1.18 65 12.24 19.77 80.23 55-90
0.6 190 35.78 55.56 44.44 35-59
0.3 157 29.57 85.12 14.88 8-30
0.15 69 12.99 98.12 1.88 0-10
PAN 10
AS PER IS 383 SAND IS IN ZONE II
-
8/2/2019 Training Report_khasa Kothi
33/33