Seminar at University of Western Sydney

INSA Rennes Huy’s Bio Hybrid columns/walls Collaboration INSA-UWS
Composite columns/walls with several encased
steel proﬁles
Ass. Prof. Quang-Huy Nguyen
Structural Engineering Research Group, INSA de Rennes, France
11 July 2014
1/25 Seminar UWS, July 11, 2014

Overview
1 Presentation of INSA Rennes
2 A little bit about me
3 Hybrid columns/walls with several encased steel proﬁles
4 Collaboration INSA-UWS

Location
 45 min from the coast
 2 hours from Paris
 An internationally renowned centre
for third-level education and research
 420 000 inhabitants,
60 000 students and 4 500 researchers
Rennes, University city
in the heart of Brittany

Presentation of INSA Rennes
Founded in 1966, INSA-Rennes is one of France’s top
graduate engineering schools, specialised in :
• Information, Communication
Systems &Technologies
• Materials, Structures &
Mechanical Engineering
INSA‐Rennes figures
• + than 1700 students
• 7 masters in engineering
• 6 research laboratories
• 160 PhD‐students
• 274 Engineers awarded a
diploma in 2012
• 7 300 INSA graduated
engineers worldwide
8th best engineering school
in France
(2013 national ranking).
INSA‐Rennes is ranked
among the top universities
of Science and Technology
in Europe, pluridisciplinary
and international.

Presentation of INSA Rennes
INSAdeRennes5/25 Seminar UWS, July 11, 2014

A little bit about me
Huy through time
2005: Graduated from INSA Rennes, France;
2005-2009: PhD in structural engineering from INSA
Rennes and University of Wollongong, Australia;
From 2010: "Maître de Conférences", INSA Rennes.
2009-2010: Research Engineer at Structural
Engineering Research Group, INSA Rennes;

My research areas
Computational modeling of composite steel-concrete
structures
Material and geometrical nonlinearities;
Time effects: creep and shrinkage;
Vibration;
Buckling.

My research areas
1Q
2Q
3Q
4Q
5Q
( )scD x
zp
Force-based formulation
x
y
1g
1g
lx
ly
2g
2g
1a
2a
2b
1b
1a
2a1b
2b
z
Co-rotational kinematic
M
A
1R
2R
0
90
100mmL 
a
a
(1)
(2)
1mmb 
1 3mmh 
2 1mmh 
(1)
(2)
Section a-a
1
2
12GPa
24GPa
0GPasc
E
E
k



Computational modeling of composite steel-concrete
structures

My research areas
Experimental and numerical studies of Concrete-Timber
Structures
Push-out static, cyclic and fire tests;
Modeling of seismic and fire behaviour
of composite Concrete-Timber floors.
Concrete-timber floor Fire test
Firetest9/25 Seminar UWS, July 11, 2014

My research areas
Experimental and numerical studies of new “hybrid” Steel-
Concrete Structures
Static Pushover tests of Composite columns reinforced by several fully
encased steel profiles;
Finite Element analysis of hybrid structures using Abaqus;
Developing of Finite Element model for buckling analysis of hybrid columns.
Hybrid beam/column Hybrid joinst

Outline
3 Hybrid columns/walls with several encased steel proﬁles
Deﬁnition
Pre-design of test specimen
Estimation of design resistance
Abaqus 3D model

Hybrid columns/walls: resistance to bending and shear
• Composite walls or columns reinforced by several fully encased steel sections are
specific composite concrete-steel structural elements used in heavily loaded structures.
• They belong to structures defined as “hybrid”, which means that they are neither
reinforced concrete structures in the sense of Eurocode 2, nor composite steel concrete
structures in the sense of Eurocode 4.
Hong Kong International Finance Center: Hybrid column with 3 steel
section as reinforcement

Gaps in knowledge are mostly related to the problem of force transmission between
concrete and embedded steel profiles:
• for the anchorage in concrete of the extremities of steel profiles;
• for the transfer of longitudinal and transversal shear between materials.
Objectives
• Fill gaps in knowledge and provide design guidance for concrete components
reinforced by several fully encased steel sections
 based on the logics of composite sections and of reinforced concrete sections,
like equivalent sections and struts and ties mechanisms
 refer to design values for bond, for shear connectors, resistances, etc, as they
are stated in Eurocode 2 and 4.
• The generic design approach will then be used to design experiments, the results of
which will serve to validate and calibrate the generic design approach.
• The outcome will be design guidance implementable in Eurocode 2 or 4.

Pre-design of specimens
The specimens are first pre-designed based on:
 the capacity of two hydraulic jacks of INSA Laboratory (3000 kN).
 the assumption of full plastic bending moment
 the assumption of equal resistances between flexion and transverse shear.
Choices of data
 Distance between two axes of supports (effective length): L = 3750 mm
 Design concrete resistance: fc = fck = 40 MPa ;
 Steel profile resistance: fy = 460 MPa (S460);
 Steel rebar resistance: fyk = 500 MPa;
 Dimensions of the cross-section: height h = 820 mm and width b = 200 mm.
Specimen
Steel
profile
Longitudinal
rebar
Stirrups
and pins
Stirrup
spacing
(mm)
Connector
Connector
spacing (mm)
C-W 3 HEB100 8 HA20 HA12 200
40 Nelson
H3L16mm
200
Resistance to combined bending and shear
Test set up for bending & shear

C-W specimen

Estimation of bending resistance
• Number of shear studs to ensure the full interaction :
Longitudinal shear force acting on the shear studs
from mid-span to the support is:
Design resistance of one Nelson H3L16mm stud
• Bending moment resistance (EC4 §6.7.3.2):
 Corresponding jack load:
L
min
Rd
1196
19 shear studs per half span
64
V
n
P
  
( / 2) ( 0) 21196kNL s s s yV F x L F x A f     
2
Rd
0.8 / 4
64kNu
v
f d
P


 
pl,Rd 1342 kNmM 
pl,Rd
pl,Rd4 4 1373
1431 kN
3.75M
M
F
L

  
Ed
N
Rd
M
Ed
V
h
/ 2L
h
b
a
z
a
z
c
z
c
z
s y sF f A 0.85 cf
cF
s y sF f A
s y sF f A

Calculation of transverse shear resistance
• Complete section is divided into two sub-sections
• Distribution of transverse shear force
into the sub-section:
 Method based on the theory of
elastic beams (Plumier et al. (2013))
 Method based on EC4-1 §6.7.3.2(4)
Sub-section 1:
1
Ed1 Ed Ed0.681
eff
eff
EI
V V V
EI
 
Sub-section 2: Ed2 Ed Ed1 Ed0.319V V V V  
pl,Rd1
Ed1 Ed Ed
pl,Rd
0.699
M
V V V
M
 
Ed2 Ed Ed1 Ed0.301V V V V  
Conclusion: Two methods give almost the same transverse shear distribution.
h
b
a
z
a
z
c
z
c
z
a
h c a
b b h 

Transverse shear resistance of sub-section 1
ha
za
za
Ed1V
100
270
270 Ed1V
aV
aV
aV
cF
cF
za
za
45°
Ed1V
cF
aV
z / 2a
za
za
za
cF
aV
aV
45

Ed1V
Proposed strut-and-tie model
 c Ed1
a
a
a Ed1
a
2
2 6
6
c a a
a c a a
a
a c a a
E h z
F V
G A E h z
G A
V V
G A E h z




c Ed1
a Ed1
0.234
0.113
F V
V V


Conclusion: The results shown that the part
of applied shear VEd1 in sub-section 1 going
into the three steel profiles is about 34%. This
is to say that the concrete struts take 66% of
applied shear VEd1.
Rd,
1
Rd1
Rd,
3 z h 1944 kN
0.234
min
8.85 8142 kN
0.113
c
c a a
a
a y
F
f
V
V
A f


  

 

  

 The failure of the sub-section 1 would be caused
by the crushing of compression struts.

Transverse shear resistance of sub-section 2
• This sub-section can be considered as RC section so the transverse shear resistance can be
computed according to EC2.
cw c 1 c
Rd2 Rd,max
0.81
797 kN
cot tan
b h f
V V
 
 
  

Transverse shear resistance of total section
The transverse shear resistance of total section is indeed deduced from:
• Shear resistance of sub-section 1
• Resistance of concrete compression strut of sub-section 2
• Resistance of transverse tie (stirrups)
Rd1
Rd2
Rd
Rd,s
1944
2781kN
0.699 0.699
797
min 2648 kN 663 kN
0.301 0.301
663 kN
V
V
V
V
 
  
 
 
    
 
 
 
 
(stirrup yielding)
 Corresponding jack load:
Rd
Rd2 1326kNVF V 
Bending/shear resistance ratio of C-W specimen: 1431 / 1326 1.08

Choices of elements types:
• Concrete: Solid element
• Steel profile: Solid element
• Steel reinforcement: Truss element
Prediction of ultimate load using Abaqus 3D model
Material models:
• Concrete damaged plasticity model
• Elastoplastic model for steel

Numerical results
Design load 1326 kN

 A design method has been developed for composite elements
reinforced by several encased steel profiles:
o Number of connectors to ensure the full interaction
o Resistance to bending: based on EC4 - plastic resistance moment
of a composite cross-section
o Resistance to shear: proposed strut-and-tie model
 The design method is more or less calibrated by 3D numerical model
 The experimental tests need to be conducted to validate this method.
Conclusions

Collaboration INSA-UWS: Hybrid columns/walls under
Elevated Temperatures
 Aims
o Understand the interaction mechanism in hybrid structures
when subjected to elevated temperatures
o Extend the knowledge of concepts such as stiffness, strength and
ductility to hybrid structures with exposed to elevated
temperatures
o Establish reliable design guidelines for hybrid structures in
existing international standards
Interaction between Steel and Concrete on Concrete Components
Reinforced by Steel Profiles under Elevated Temperatures
Quang-Huy Nguyen, INSA de Rennes
Olivia Mirza, UWS

Collaboration INSA-UWS: Hybrid columns/walls under
Elevated Temperatures
 Approach
o Numerical Analysis Phase: Thermomechanical 3D Abaqus model
o Experimental Phase
o Developing a Generic Approach Phase
Section A-A
82
20A A
unit: cm
200
Interaction between Steel and Concrete on Concrete Components
Reinforced by Steel Profiles under Elevated Temperatures
Quang-Huy Nguyen, INSA de Rennes
Olivia Mirza, University of Western Sydney

Thanks for your attention !
... any questions ?

Seminar at University of Western Sydney

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