Experimental study of precast portal frame
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Transcript of Experimental study of precast portal frame
EXPERIMENTAL STUDY OF PRECAST
PORTAL FRAME
2CL404 – CIVIL ENGINEERING PROJECT
ee
Presented By:-
SAGAR HALWAWALA (11BCL014)HIMANSHU MANOLKAR (11BCL015)SATISH KAMBALIYA (11BCL016)MEET KOTADIA (11BCL020)
Guided By:-Dr. P.V. Patel
Introduction
• Precast concrete :- Construction product produced by casting
concrete in a reusable mould or "form" which is then cured
in a controlled environment, transported to the construction
site and lifted into place.
• Increasingly popular in the construction industry.• Increasingly popular in the construction industry.
• Also referred to as Modern Methods of Construction (MMC).
• Extensively used for a wide variety of projects, from railway
sleepers to bridge elements, housing and stadia.
• Reduction in waste on construction site by as much as 50%
when compared to more traditional approaches.
Introduction cont...
• It is due among other factors to the advantages related to the
reduction in construction times, work force and in situ labors,
as well as a more favorable cost-benefit relation, less
environmental impacts, and greater control and final quality
of the elements.
• Utilizing a Precast Concrete system offers many potential• Utilizing a Precast Concrete system offers many potential
advantages over site casting of concrete. The production
process for Precast Concrete is performed on ground level,
which helps with safety throughout a project.
• There is a greater control of the quality of materials and
workmanship in a precast plant rather than on a construction
site.
Types of Precast System.
Depending on the load bearing structure, precastsystems can be divided into the followingcategories:
� Large-panel systems
� Frame systems
�Slab-column systems with walls
�Mixed systems
�Volumetric construction
Precast Building In India
Pragati Tower is a
G+23 storeys fully
precast residential
building project with
6 towers at6 towers at
Bhoiwada, Parel,
Mumbai, India to
rehabilitate slum
dwellers.
Need Of Precast Construction
• Precast concrete solutions can provide construction elements thatare made of recycled materials that generate small amounts ofwaste through the manufacturing and erection phases. Theseprecast products are widely used in the following sectors:
� Residential (floors)
� Stadia� Stadia
� Infrastructure (roads, railways, bridges, sewage)
� Prisons
� Medium and high rise building
� Hospitals
� Commercial and industrial buildings
Need Of Precast Construction cont.
• Their utilization saved construction time and cost,
insured better quality control, and suggested the
achievement of standardization.
• Its fulfills criteria of three “R” of Sustainable
Development ie.Development ie.
� Reduce
� Recycle
� Reuse
Advantage Of Precast Construction
• Quick erection times.
• Reduced need for plant on site.
• Easier management of construction sites.
• Better overall construction quality.• Better overall construction quality.
• Ideal fit for simple and complex structures.
• The forms used in a precast plant may be reusedhundreds to thousands of times before they haveto be replaced, which allow cost of formwork perunit to be lower than for site-cast production.
Limitations
• High Initial cost.
• Lack of local availability of elements.
• Transportation
• Erection• Erection
Objective Of Project
The key objectives of study are as follows.
• To study the basics of precast joints.
• To study the behaviour of joints in precast concrete• To study the behaviour of joints in precast concrete
portal frame by experimental study.
• To compare experimental results of monolithic
specimen and precast specimens (with and without
corbel) and derive conclusion which is comparatively
efficient.
Scope Of Study
• Analysis and design of the Portal Frames.
• Taking a building with continuous slab and designing
intermediate portal frame from it.
Scope Of Study
• Designing of a monolithic portal frame andtwo precast portal frame one with corbel andone without corbel.
• Casting of the scaled down specimen of each• Casting of the scaled down specimen of eachtype of the portal frame.
• Testing the portal frame as per experimentalsetup.
• Based upon experimental data, comparingportal frames and deriving out conclusion.
MIX DESIGN
• Design Data
1. Characteristic strength required at 28 days = 25 MPa
2. Maximum size of aggregate = 10 mm2. Maximum size of aggregate = 10 mm
3. Degree of workability = medium
4. Degree of quality control = fair
5. Type of exposure = Moderate
• Test data of materials:-
1. Compressive strength of OPC cement 53
N/mm2
2. Specific gravity of cement = 3.152. Specific gravity of cement = 3.15
3. Specific gravity of coarse aggregate = 2.78
4. Specific gravity of fine aggregate = 2.54
Final Mix Design
Concrete
Grade
Cement
OPC 53
W/C Coarse
Aggregate
Fine
Aggregate
grade
M-25 1 0.54 2.51 1.96
M-25 390 kg 210.6 978.84 kg 762.61 kg
Design Consideration
• Three test specimens of one forth scale model were cast and
tested under two point load. The design and detailing of
portal frame had been done based on the guidelines given in
IS: 456-2000, IS: 13920.
• Dimension of actual portal frame of :-• Dimension of actual portal frame of :-
1. Span – 8m
2. Height – 4m
3. Cross section of beam- 400x600
4. Cross section of column – 400x800
Dimensional Analysis and Scaling Of
Portal Frame
• As large specimens were difficult to handle so casting
of scaled down specimen for study.
• Therefore using Buckhimgam Pie theorem and taking
a reduction factor of 1:4 calculation were made and
following model was decided for experimental
testing.
1. Span – 2m
2. Height – 1m
3. Cross section of beam- 100x150
4. Cross section of column – 100x200
Precast Portal Frame
1).Without Corbel
• This frame design consists of a L shapedcolumn spanning 300 mm out of column with150mm bars projecting out, accompanied150mm bars projecting out, accompaniedwith 900mm beam casted separately with150mm bars projecting out, welding of110mm on either side of the beam with a gapof 150mm in between the beam approachingbeam from column side.
2). With Corbel
• In this frame corbel of 110 mm long and
200mm depth were designed having two
dowel bars in corbel and two M10 bolts were
used.
• Beam 1770mm long having hole for bolts
were designed and welding of 110 mm of
columns bar and beam bar were done.
• 15mm spacing were kept on both side of
beam for concreting.
Steps for Experimental Analysis
1. Trial mix for the concrete mix design
2. Casting of covers (20mm)
3. Setting up of form work
4. Tie up the reinforcement cage4. Tie up the reinforcement cage
5. Connection of column and base plate by welding
6. Placement of the reinforcement cage into the formwork
7. Casting of the Portal Frame
8. Curing
9. Setting up of portal frame in test set up frame
Trial mix for the
concrete mix
design
Three cubes of
150*150*150mm were150*150*150mm were
casted as per obtained mix
design for M25 grade of
concrete and were tested
for 7 days strength.
The cubes were
tested on Universal
Testing Machine after
seven days and result
obtained was 16.5
N/mm^2. Which is
66% of 25N/ N/mm2.66% of 25N/ N/mm .
Casting of covers
(20mm)
• Tea cups were used forcasting of mortar coverhaving proportion of1:2. and then bindingwire were inserted in it.
• Cups were kept in waterand cured for threedays.
1).Methodology For Monolithic Portal
Frame
Tie up the
reinforcement cagereinforcement cage
of column
•Column with end to
end length of 1075mm
and beam with end to
end length of 2200 mm
was casted.
•8 mm thick steel plate
was used to serve purpose
Connection of
column and base
plate by welding
was used to serve purpose
of footing for stability of
the frame.
•Reinforcement bars of
column at bottom was
welded with plate by
120mm length.
•Casting of frame were performed,
vibrator was used for removing the voids.
Cubes were arranged on sides of were
to prevent expulsion of formwork and to
have desired shaped frame.
Casting of the
Portal Frame
Curing
•After Casting, curing were done for 28
days and gunny bags were used for this
purpose.
•After 28 days of casting, the frame was
arranged as per set up.
Test Setup
• Test setup consists of loading frame on which four ISMB 150
were rigidly fixed by the means of metal nuts, bolts and wires.
Upon this portal frame having base plate 8mm thick is
connected to the ISMB 150 by the help of clamps.
Furthermore the testing assembly consists of 5 dial gaugesFurthermore the testing assembly consists of 5 dial gauges
placed at 100mm, 450mm, 1000mm, 1450mm and 1900mm
from the left hand side respectively.
• For application of load a 250 kN hydraulic jack is mounted at
the top of the loading frame facing downward side below
which an ISMB 200 section was placed over two roller support
330mm from the middle of the support on either side.
2).Methodology For Precast Portal
Frame without Corbel
•Placing
Reinforcement Cage
into formwork of 900
mm long.
•Bars extending on
both sides of 130mm
long for connecting it
to bars of column.
Different components were arranged in level to have proper connections.
Reinforcing Bars extending from columns and Beams are welded of length 110mm
with the help of mobile welder.
•Placing of form work for Micro Concreting, which were
sealed with M-seal in order to prevent leakage.
Using Micro-concrete in proportion of 1:2 with proper stirring, and
pouring Micro Concrete and curing it for 28 days.
Test Setup
• Two beam of ISMB 300 were kept at end and over it beam of
ISMB 500 were kept and above it specimen were kept. Above
specimen two rollers of 50mm were kept for providing
support and above it beam ISMB 200 were kept and spacer of
100mm were used and then jack of 100kN, 300mm height
were used thus completing full length of 2000mm height.were used thus completing full length of 2000mm height.
• For application of load a 100kN hydraulic jack is mounted at
the top of the loading frame facing downward side below
which an ISMB 200 section was placed over two roller support
330mm from the middle of the support on either side.
3).Methodology For Precast Portal
Frame with Corbel
In this frame
Corbel of size
110*110*200
and two Dowel
Bars of 10mmBars of 10mm
diameter are
designed.
Fixing the bolts emerging out from the column into the beam and welding the Reinforcing
Bars of column and beam with the help of mobile welder, then Micro concreting is done.
•After casting of Pre-cast
elements, Micro-concreting is
done by proper stirring in
proportion of 1:2.
•And curing it for 28 days.
•Then setting up the frame in the
laboratory, and test setup islaboratory, and test setup is
similar to that of frame without
corbel.
Results Of Monolithic Portal
Frame
40
50
60
LOA
D (
kN
)
Load vs Deflection
900L
0
10
20
30
0 5 10 15 20 25 30
LOA
D (
kN
)
DEFLECTION(mm)
900L
450L
centre
900R
450R
30
40
50
60
70
80
90LO
AD
(KN
)LOAD VS DEFLECTION AT 100 mm FROM LEFT
0
10
20
30
-1 0 1 2 3 4 5 6 7 8
DEFLECTION(mm)
Monolithic Without Corbel With Corbel
40
50
60
70
80
90
LOA
D(K
N)
LOAD VS DEFLECTION AT 550 mm FROM LEFT
0
10
20
30
0 2 4 6 8 10 12 14 16
LOA
D(K
N)
DEFLECTION
Monolithic Without Corbel With Corbel
40
50
60
70
80
90
LOA
D(K
N)
LOAD VS DEFLECTION AT 1000 mm FROM LEFT
0
10
20
30
0 5 10 15 20 25 30
LOA
D(K
N)
DEFLECTION
Monolithic Without Corbel With Corbel
40
50
60
70
80
90
LOA
D(K
N)
LOAD VS DEFLECTION AT 1450 mm FROM LEFT
0
10
20
30
0 5 10 15 20
LOA
D(K
N)
DEFLECTION
Monolithic Without Corbel With Corbel
40
50
60
70
80
90
LOA
D(K
N)
LOAD VS DEFLECTION AT 1900 mm FROM LEFT
0
10
20
30
0 2 4 6 8 10
DEFLECTION
Monolithic Without Corbel With Corbel
Observation For Cracks Of Portal
Frame without Corbel
Shear crack
observed at
52.5 kN. @left
corner of
frame
Summary• In this study taking a building with continuous
slab and designing intermediate portal framefrom it.
• Further casting and testing of one forth scaledspecimen of monolithic portal frame , and twospecimen of monolithic portal frame , and twoprecast portal frame one with corbel and onewithout corbel were carried out.
• Testing of the portal frames were done as perexperimental setup.
• Based upon experimental data, comparingportal frames and deriving out conclusion.
Conclusion• Deflection pattern through out the testing followed
similar pattern i.e. maximum deflection is observed incase of monolithic frame, than portal frame withoutcorbel followed by portal frame with corbel.
• This shows that Monolithic Frame is more ductile thanPre-cast Frame, but carries low load.Pre-cast Frame, but carries low load.
• However it is observed while testing portal frame withthe corbel that deflection at center of span weresimilar to deflection at 450mm distance on both side ofcenter.
• However this could be attributed to presence of thecorbel as due to presence of corbel proper fixity is notobtained at support and there is rotation which wouldresults in similar kind of deflection.
28.4
15
20
25
30
De
fle
ctio
n(k
N)
Maximum Deflection of Portal Frame(mm)
10.1
12.8
0
5
10
15
With Corbel Without Corbel Monolithic
De
fle
ctio
n(k
N)
55
67.5
80
40
50
60
70
80
90
Ult
ima
te L
oa
d(k
N)
Ultimate Load
monolithic with corbel without corbel
load 55 67.5 80
0
10
20
30
40
Ult
ima
te L
oa
d(k
N)
Type of system
• Load carrying capacity of frame without corbelis 15% more than frame with corbel and 31%more than monolithic frame.
• Deflection is also between monolithic andwith corbel frame.
• Thus portal frame without corbel is more• Thus portal frame without corbel is moreefficient comparatively.
• After going through study it can be wellconcluded that the precast construction canperform well unconventional to that of theexisting belief.