Seminar at University of Western Sydney

INSA Rennes Huys Bio Hybrid columns/walls Collaboration INSA-UWS

Composite columns/walls with several encasedsteel 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 centrefor 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 Frances top

graduate engineering schools, specialised in :

Information, Communication Systems &Technologies

Materials, Structures & Mechanical Engineering

INSARennesfigures

+than 1700students

7mastersinengineering

6research laboratories

160PhDstudents

274Engineersawardedadiplomain2012

7300INSAgraduatedengineers worldwide

8thbestengineeringschoolinFrance(2013nationalranking).INSARennesis rankedamong thetopuniversitiesofScienceandTechnologyinEurope,pluridisciplinaryandinternational.



Presentation of INSA Rennes

INSA de Rennes5/25 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: "Matre de Confrences", INSA Rennes.

2009-2010: Research Engineer at Structural Engineering Research Group, INSA Rennes;



My research areasComputational modeling of composite steel-concretestructures

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

1g1g

lx

ly

2g2g

1a

2a

2b

1b

1a

2a1b

2b

z

Co-rotational kinematic

M

A

1R

2R090

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-concretestructures



My research areasExperimental and numerical studies of Concrete-Timber StructuresPush-out static, cyclic and fire tests;

Modeling of seismic and fire behaviourof composite Concrete-Timber floors.

Concrete-timber floor Fire test

Fire test9/25 Seminar UWS, July 11, 2014


My research areasExperimental 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 profilesDefinitionPre-design of test specimenEstimation of design resistanceAbaqus 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



Hybrid columns/walls: resistance to bending and shearGaps 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 specimensThe 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 SteelprofileLongitudinalrebar

Stirrupsand pins

Stirrupspacing(mm)

Connector Connectorspacing (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



Hybrid columns/walls: resistance to bending and shearC-W specimen



Hybrid columns/walls: resistance to bending and shearEstimation of bending resistance

Number of shear studs to ensure the full interaction :

Longitudinal shear force acting on the shear studsfrom mid-span to the support is:

Design resistance of one Nelson H3L16mm stud

Bending moment resistance (EC4 6.7.3.2):

Corresponding jack load:

Lmin

Rd

1196 19 shear studs per half span64

Vn

P

( / 2) ( 0) 21196kNL s s s yV F x L F x A f

2

Rd0.8 / 4

64kNuv

f dP

pl,Rd 1342 kNmM

pl,Rd

pl,Rd4 4 1373 1431 kN3.75M

MF

L

EdNRdM

EdV

h

/ 2Lh

b

az

az

cz

cz

s y sF f A 0.85 cf

cF

s y sF f A

s y sF f A



Hybrid columns/walls: resistance to bending and shearCalculation 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: 1Ed1 Ed Ed0.681eff

eff

EIV V V

EI

Sub-section 2: Ed2 Ed Ed1 Ed0.319V V V V

pl,Rd1Ed1 Ed Ed

pl,Rd0.699

MV V V

M

Ed2 Ed Ed1 Ed0.301V V V V

Conclusion: Two methods give almost the same transverse shear distribution.

h

b

az

az

cz

cz

ah c ab b h



Hybrid columns/walls: resistance to bending and shearTransverse 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

cFaV

aV45

Ed1V

Proposed strut-and-tie model

c Ed1aa

a Ed1a

2

2 6

6

c a a

a c a a

a

a c a a

E h zF V

G A E h z

G AV 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 kN0.234

min

8.85 8142 kN0.113

cc a a

aa y

Ff

V

VA f

The failure of the sub-section 1 would be caused by the crushing of compression struts.



Hybrid columns/walls: resistance to bending and shearTransverse 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,max0.81

797 kNcot tan

b h fV 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

Rd2Rd

Rd,s

1944 2781kN0.699 0.699

797min 2648 kN 663kN0.301 0.301

663kN

V

VV

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



Hybrid columns/walls: resistance to bending and shearNumerical results

Designload 1326kN




A design method has been developed for composite elementsreinforced by several encased steel profiles:

o Number of connectors to ensure the full interaction

o Resistance to bending: based on EC4 - plastic resistance momentof 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 underElevated Temperatures

Aims

o Understand the interaction mechanism in hybrid structureswhen subjected to elevated temperatures

o Extend the knowledge of concepts such as stiffness, strength andductility to hybrid structures with exposed to elevatedtemperatures

o Establish reliable design guidelines for hybrid structures inexisting international standards

Interaction between Steel and Concrete on Concrete ComponentsReinforced by Steel Profiles under Elevated Temperatures

Quang-Huy Nguyen, INSA de Rennes

Olivia Mirza, UWS



Collaboration INSA-UWS: Hybrid columns/walls underElevated 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 ComponentsReinforced by Steel Profiles under Elevated Temperatures

Quang-Huy Nguyen, INSA de Rennes

Olivia Mirza, University of Western Sydney



Thanks for your attention !

... any questions ?


Presentation of INSA RennesLocationINSA RennesINSA Rennes video

A little bit about meHuy through timeMy research areas

Hybrid columns/walls with several encased steel profilesDefinitionPre-design of test specimenEstimation of design resistanceAbaqus 3D model

Collaboration INSA-UWSAimsApproach

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