concrete filled steel tubular columns using gs sheet
TRANSCRIPT
Welcome to Our Thesis
Presentation
Heaven’s Light is Our Guide
Rajshahi University of Engineering & TechnologyDepartment of Civil Engineering
EXPERIMENTAL INVESTIGATION ON CONCRETE FILLED STEELTUBULAR COLUMN USING GS SHEET STRENGHTENED WITH
SELF-COMPACTING CONCRETE COLUMN.
SUPERVISED BY PRESENTED BY
Dr. Tarif Uddin Ahmed Al-Amin Bin AzizProfessor Roll no. 100018Department of Civil Engineering Moniruzzaman RubelRajshahi University of Engineering & Technology Roll no. 100093
Presentation OutlineIntroductionBackgroundApplicationObjectivesScope of workLaboratory InvestigationExperimental InvestigationConclusion
IntroductionRecently different types of composite material have been widely applied to concrete column to provide better performance of column system. Concrete-filled steel tube column system has turned out to be one of the most successful composite concrete column. The concrete-filled steel tubular column offers numerous structural benefits-
High strength, fire and corrosion resistances Favorable ductility and large energy absorption capacities There is also no need for the use of shuttering during concrete
construction Construction cost and time are reduced.
These advantages have been widely exploited and have led to the extensive use of concrete-filled tubular structures in civil engineering structures.
BackgroundBaoChun Chen in 2009, this paper briefly introduces the present situation of concrete filled steel tube arch bridges in China. More than 200 concrete filled steel tubular arch bridges were
investigated and analyzed.
Qing Quan Liang and Sam Fragomeni in 2009, Quin and Sam had presented accurate constitutive models for normal and high strength concrete confined by either normal or high
strength circular steel tubes.
Shankar Jagadesh in May 2014, Concrete-filled steel tubes are gaining increasing prominence in a variety of engineering structures. The study about the behavior and the
characteristics of concrete filled steel tubular columns is the prime need of the hour.
Most of the investigation have been conducted using cast iron steel column, carbon fiber reinforced polymer or other types of steel columns of various shapes.
Experimental Investigation on GS sheet steel tube columns have been rarely used.
So we are investigating on CONCRETE FILLED STEEL TUBE USING GALVANIZING STEEL SHEET COLUMNS.
ApplicationConcrete filled steel tube structure are widely used.
Used in buildings to avoid having large size columns
In super high-rise structures like CANTON TOWER
Applied in many types of bridges such as arch bridges, cable bridges, suspension bridges and truss bridges.
Used in the construction and the upgrade of poles and transmission towers as well
Steel tube columns
Electric pole
Canton Tower, china
CFST used in bridges
Building frame construction
ObjectivesTo evaluate the Compression effect of concrete columns
strengthen by using the GS sheet materials.
To observe the behaviors of the confined and unconfined (self-compacted) concrete columns subjected to monotonic axial loading.
Evaluating the stress-strain & deflection curve for confined and unconfined specimens.
To obtain a concept about the variation of results from stress-strain curve.
Scope of WorkThis study discusses an experimental process in which
i. Short steel tube columns are taken under consideration to compare the strength variation with the normally casted self-compacted unconfined columns.
ii. The slenderness ratio of the column specimen was taken under consideration for the computation of strength
iii. Monotonic axial load was applied to the circular face of the columns.
iv. The benefits of the confinement effect were focused in the study by means of both experimental and analytical point of view.
Laboratory InvestigationLaboratory Investigation is divided into three different stages:i. Determination of physical properties of various material including specific gravity, BSG,
ACV, Compressive strength of cement, Fineness modulus etc.
ii. Preparation of steel tubular concrete columns and unconfined concrete columns were prepared in two mix proportions.
Concrete mix proportions
Series no. Proportion Confined
specimen
Unconfined
specimen
Water-Cement
Ratio
1 1 : 2 : 4 C1, C2, C3,
C4, C5, C6
U1, U2, U3 .51
2 1 : 1.5 : 3 C7, C8, C9,
C10, C11, C12
U4, U5, U6 .51
Illustration of preparing molds
Cutting of GS sheet. Rounding the steel sheet into circular shape
Welding the GS sheet columnTubular column after welding.
GS sheet tubular columns
Series no. Specimen no. Outer dia Φ
(cm)
Height (cm)
1
U1 19.05
60.96U2 13.97
U3 8.89
2
U4 19.05
60.96U5 13.97
U6 8.89
Series
no.
Specime
n no.
Outer
dia Φ
(cm)
Core
dia Φ
(cm)
Thickness
of steel columns
(cm)
Heightof
columns (cm)
1
C1 19.25 19.05 0.1 60.96
C2
C3 14.17 13.91 0.1 60.96
C4
C5 9.09 8.89 0.1 60.96
C6
2
C7 19.25 19.05 0.1 60.96
C8
C9 14.17 13.91 0.1 60.96
C10
C11 9.09 8.89 0.1 60.96
C12
Details of test specimen for Confined Columns & Unconfined columns
Casting of steel tubular columns after 24 hours.
Casting of unconfined columns after 24 hours
III. The specimens were tested in the appropriate set-up.
Test setup
Experimental InvestigationSerialNo.
Castingcriteria
Specimen
Crackingload(kN)
Ultimateload(kN)
Ultimate VerticalDeformation(mm)
01
Confined(1:2:4)
C1 592 608 3.048C2 427 448 3.239
C3 340 358 2.667
C4 325 349 3.747C5 195 216 2.858
C6 178 197 .9525Unconfined
(1:2:4)U1 295 322 3.302
U2 170 186 4.166U3 81 92 3.215
02
Confined(1:1.5:3)
C7 422 443 2.858C8 415 430 1.079
C9 285 302 3.429C10 347 368 3.683C11 219 235 2.261
C12 138 152 1.753Unconfined
(1:1.5:3)
U4 288 308 3.901U5 124 141 2.096
U6 43 66 2.136
0 0.1 0.2 0.3 0.4 0.5 0.60
5
10
15
20
25
C1Polynomial (C1)C7Polynomial (C7)U1Polynomial (U1)
STRAIN %
STR
ESS
(MPa
)
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.80
5
10
15
20
25
C3Polynomial (C3)C9Polynomial (C9)U2Polynomial (U2)
STRAIN %
STR
ESS
(MPa
)
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50
5
10
15
20
25
30
35
C6Polynomial (C6)C12Polynomial (C12)U3Polynomial (U3)
STRAIN %
STR
ESS
(MPa
)
SpecificationsC1-C6 confined (1:2:4)
C7-C12 confined (1:1.5:3)U1-U3 unconfined (1:2:4)
U4-U6 unconfined (1:1.5:3)
0 0.1 0.2 0.3 0.4 0.5 0.6 0.70
5
10
15
20
25
C2Polynomial (C2)C8Polynomial (C8)U4Polynomial (U4)
STRAIN %
STR
ESS
(MPa
)
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50
5
10
15
20
25
C10Polynomial (C10)C4Polynomial (C4)U5Polynomial (U5)
STRAIN %
STR
ESS
(MPa
)
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50
5
10
15
20
25
30
35
C11Polynomial (C11)C5Polynomial (C5)U6Polynomial (U6)
STRAIN %
STR
ESS
(MPa
)
SpecificationsC1-C6 confined (1:2:4)
C7-C12 confined (1:1.5:3)U1-U3 unconfined (1:2:4)U4-U6 unconfined (1:1.5:3
FAILURE OF COLUMN SPECIMEN
Fails at top portion
Fails at mid portion
Fails at top
Failure zone
(bottom)Confined column Unconfined
columns
Conclusioni. The confined column has less axial deformation in comparison to the
unconfined column when subjected to same amount of load.
ii. The failure of the confined columns initiates from the development of deformation in steel sheet at top and bottom portion of the column, when the
ultimate load is applied the deformation initiates in the middle portion.
iii. In case of shear failure, the concrete encased fail first due to shear. In the second modes of failure there is a plastic deformation in the GS sheet.
Recommendationi. From the experimental investigation, it is observed that most of the columns failed in shear, this type of failure occurred due to presence of weak concrete at the failure zone for further research the columns should be casted carefully so that each and every portion of the column may have uniform density of concrete.
ii. Major work is done on concrete filled steel tubular column is experimental. Still, there is a need for numerical study is needed to check the parameters which affect the ultimate strength.
iii. As the BNBC code has not thrown light, for calculating the strength of concrete filled steel tubular column, further research is needed.