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(1)

Pus h Out Te s t for

Concre te Fille d Ste e l

Tubula r Us ing Diffe re nt Stre ngths of Ultra High Pe rfom a nce Concre te

VEB 4054 Final Year Project II September 2022

: Muhammad Zulfaqar Bin Abdul Razak Na m e

: 17010089 ID No.

: Dr. Ehsan Nikbakht Jarghouyeh Supe rvisor

: Prof. Nasir Shafiq Int. Exa m nie r

: Ir. Khairul Anwar Masu'd Ext. Exa m ine r

VIVA Pre se n t a t io n

(2)

• Introduction

• Problem

• Literature Review

• Objective

• Methodology

• Scope of study

• Conclusion

• Results

• Recommendations

• QnA

Ta ble of Conte nts

(3)

A hollow steel tubular filled with concrete or reinforced concrete.

High strength, stiffness and ductility High rise buildings, bridges piers

Introduction

Concre te Fille d Ste e l Tubula r

Transfer of stress between the concrete and steel.

Bonding strength between the steel and concrete.

Cross section, dim ension, age, type, roughness, strength

Com posite Action

(4)

There is a lack of consensus regarding the effect of high com pressive strength on

bond strength between the steel and concrete in CFST where som e stated a sim ilar trend with norm al concrete and

som e the opposite

Proble m

Sta te m e nt

(Xiushu et al., 2015, Xu et al., 2009, Morishita et al., 1979)

(5)

To e xa m ine the inte ra ction be twe e n the com pre ssive stre ngth of concre te core a nd bonding stre ngth of ste e l a nd concre te in CFST

Obje ctive a nd Scope of Study

• Design Mix

• Compressive Strength of 120Mpa

• Trial Mixes

Ultra High Perfomance Concrete

• Casting CFST samples

• Push Out Test

• Analysis

Concrete Filled Steel Tubular

Objective

Scope of Study

(6)

• Adequate confinement delays the local buckling.

CFST Mechanical Properties

Composite Action

Lite ra ture Re vie w

"Ma n ika n d a n a n d Um a ra n i, 20 21"

Lo a d b e a rin g ca p a cit y im p ro ve s w it h gra d e o f co n cre t e

"Ta o , Uy, a n d e t a l., 20 11"

Me ch a n ica l p ro p e rt ie s ca n b e im p ro ve d d u e t o co m p o sit e a ct io n b e t w e e n st e e l a n d co n cre t e .

"Ha n e t a l., 20 14 "

(7)

Arise from the combination of mechanisms, Chemical Ad h e sio n , Micro lo ckin g, Ma cro lo ckin g

Mechanism of Bonding Strength

Macrolocking was the main mechanism in CFST columns contributing to the bond strength followed by friction, and the influence of chemical adhesion was very limited.

Lite ra ture Re vie w

(Ta o e t a l. 20 11, Vird i a n d Do w lin g 1975, Ch e n e t a l. 20 0 9)

Ma cro lo ckin g - d u e t o m a n u fa ct u rin g t o le ra n ce s a sso cia t e d w it h in t e rn a l d im e n sio n s.

Micro lo ckin g - ca u se d b y su rfa ce ro u gh n e ss in m icro sco p ic sca le .

Ch e m ica l a d h e sio n - in sign ifica n t a n d in flu e n ce d b y va rio u s fa ct o rs su ch a s w / c ra t io .

(Zh o n g e t a l., 20 16)

(8)

Com pre ssion Te st

Me thodology

UHPC Material Preparation

Tr ia l M ix

Co m p r e ssio n Te st

GGBS, Silic a , Gr o u n d Q u a r t z, St e e l fib e r , w a t e r r e d u c e r

3 sa m p le s p e r m ix w it h 3, 7, 28 d a ys o f c u r in g

Th e c o m p r e ssive st r e n g t h w h ic h is n e e d e d t o b e m o r e t h a n 120 M p a

0 1

0 2

0 3

Push Out Te st

St e e l Tu b u la r Pr e p a r a t io n

Ca st in g CFST Sa m p le

Pu sh O u t Te st

Pr e p a r e t h e st e e l h o llo w r e q u ir e d

Ca st in g UHPC in sid e t h e st e e l h o llo w

Ap p lie d lo a d t o t h e c o n c r e t e c o r e o f CFST

0 4

0 5

0 6

(9)

Ma te ria l Pre pa ra tion

To utilize UHPC, the subsequent mix needs t o a ch ie ve 120 Mp a o f St re n gt h .

UHPC d o n o t re q u ire a ggre ga t e s, in st e a d n e e d s GGBS, silica , q u a rt z, fly a sh , w a t e r

re d u ce r

Tria l Mix

Up o n d e sign m ix, n e e d t o t e st t h e a u t h e n t ic o f t h e d e sign m ix, h e n ce t ria l m ix.

A 10 0 m m x10 0 m m x10 0 m m w a s u se d w it h 2 t yp e s o f cu rin g, h e a t a n d w a t e r.

Ma te ria ls Pre pa ra tion

(10)

UHPC De s ign Mix

(11)

Com pre ssion Te st Se tup

After curing for specific 3, 7, and 28 days,

co m p re ssive t e st w a s d o n e t o e n su re t h e co m p re ssive st re n gt h e a ch sa m p le s

Com pre s s ion Te s t

(12)

Ste e l Hollow Pre pa ra tion

2 samples 300mm of circular steel hollow a n d 2 sa m p le s o f 250 m m sq u a re st e e l

h o llo w w a s cu t a n d p re p a re d

Ste e l Hollow

(13)

Push Out Te st

Universal Testing Machine of 200kN

ca p a cit y w a s u se d t o p u sh t h e co n cre t e co re u n t il it d e -b o n d s w it h t h e st e e l

Pus h Out Te s t

(14)

Compressive Strength

Push Out Test

All together, 8 trial m ixes was done to achieve the required com pressive

strength, greater than 120Mpa

4 sam ples of CFST with 2 different shapes were tested in push out.

R es ul ts a nd An al ys is

(15)

3 Days 7 Da ys 28 Da ys

Du ra Ce m t e

c

BSI Du ra (2n d ) BSI (2n d ) Priva t e

Du ct a l Priva t e 150

10 0

50

0

Compressive Strength (Mpa)

Co m pr essi ve Str en gth

De sign Mixe s

14 0 Mp a

127Mp a

(16)

Co m pr essi ve Str en gth

(17)

Ide a lize d & Re a lis tic Re s pons e of Pus h Out Te s t

(Tao et al., 2011) (Vird i a n d Do w lin g, 1975)

(18)

Pus h Out Te s t

• At 200kN the sa m ple with 140Mpa

com pre ssive stre ngth ha d a slip of 4m m

whe re a s the concre te with 127Mpa ha d a slip of 11m m .

Circula r Cross Se ction

• sa m ple with 140Mpa sim ila r to Type 3 loa d slip curve .

• Sa m ple with 127Mpa sim ila r to Type 2 loa d slip curve .

(19)

Pus h Out Te s t

Squa re Cross Se ction

• At 200kN the sa m ple with 140Mpa

com pre ssive stre ngth ha d a slip of 8m m

whe re a s the concre te with 127Mpa ha d a slip of m ore tha n 10.3m m .

• sa m ple with 140Mpa sim ila r to Type 3 loa d slip curve .

• Sa m ple with 127Mpa sim ila r to Type 2 loa d slip curve .

• By com pa rison,

140Mpa ha s a be tte r bonding stre ngth

com pa re d to 127Mpa of com pre ssive

stre ngth.

(20)

The objective of this research is achieved with the results obtained from the tests which can conclude the

significance of the com pressive strength

Com pressive Strength of the concrete core of CFST can significantly affect the bonding

strength of the concrete steel.

Conclus ion & Re com m e nda tion

Current Push Out Test has lim itations.

Im partial other types of forces, bending m om ent.

Load transfer from a elem ent to another through plates or others.

Lim ita tions of Te sts

Too little com parison of sam ples due to various factors of tim e costs and resources.

Sm a ll Sca le of Da ta

(21)

Tha nk you!

Do you have any questions?

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