finite element analysis of a hybrid rcs beam-column connection

Intro FE model Results Conclusions RCS Joint test

Finite Element analysis of a hybrid RCSbeam-column connection

Quang-Huy Nguyen*; Mohammed Hjiaj*; Xuan HuyNguyen**; Huy Cuong Nguyen**

* Structural Engineering Research Group, INSA de Rennes, France** University of Transport and Communications, Vietnam

12 May 2015

1/24 International Conference CIGOS Paris, 11-12 May 2015


Overview

1 Introduction

2 3D Finite Element model

3 Results and Discussions

4 Conclusions

5 RCS Joint tested at UTC of Vietnam



Introduction

Smart Composite Components

Concrete Structures Reinforced by Steel Profiles

SmartCoCo project

Grant Agreement RFSR-CT-2012-00031

Herv DEGEE, Teodora BOGDAN, Andr PLUMIER Universit de Lige, Coordinator

Nicoleta POPA, Louis-Guy CAJOT ArcelorMittal

Jean-Marie DE BEL, Pierre MENGEOT BESIX SA

Quang-Huy NGUYEN, Mohammed HJIAJ, Hugues SOMJA INSA Rennes

Ahmed ELGHAZOULI, Dan BOMPA Imperial College London



Introduction

Overview of the project

Develop design guidance for hybrid structural situations which are:

neither reinforced concrete Eurocode 2, ACI 318

nor composite steel-concrete Eurocode 4, AISC 2010

Practical situations analysed

Composite column sections with more than one fully encased steel profile

Hong Kong International Finance Center: Hybrid column with 3 steel

section as reinforcement



IntroductionPractical situations analysed

Composite elements used to transfer forces from composite beams to RC columns or walls, namely RCS joint

Connections of RC flat slabs or beams to columns or walls

Hybrid joint



IntroductionRCS joint overview

Design model proposed by Kanno and Deierlein (2002) for RCS joints;

The model is the improvement of ASCE Guidelines RCS joints in buildings located in low to moderate seismic risk zones.



IntroductionRCS overview

Nishiyama et al. (2004): Guidelines for Seismic Design of Steel-Concrete

Composite Structures;

Design based the "strong column-weak beam" philosophy;

The joint failure modes are similar to the design guidelines of the ASCE 1994, for

the shear failure and bearing failure



IntroductionObjective:

Study a new type beam-column joint which is the connection of steel beam to RC column: A steel profile is totally embedded into a RC column is used to

connect the beam through the steelwork part of composite section

Particular attention will be paid to

The force transmission problem between the embedded steel profile and the

concrete of the column

The failure mode of this new type of connection

o Different anchorage lengths

o Different concrete classes

Studied hybrid joint



IntroductionTest Specimens

The four specimens were pre-designed based on the tentative design method

developed within Smartcoco project.



3D Finite Element modelAbaqus 3D model of a half

exterior RSC joint specimen

Interaction and constrain conditions:

Embedded constraint can be used for the

interaction between rebars and concrete

surrounding;

Hard contact with frictionless for surface to

surface contact between the profile and the

concrete.

Material models:

For concrete: Damage Plasticity model (Lee and

Fenves 1998).

For steel: Von Mises yield criterion with

isotropic hardening rule.



3D Finite Element modelElement type and meshing

C3D8R-element: 8-node linear brick element with reduced integration stiffness;

T3D2-element: 2-node linear 3-D truss element

HJS4 specimen:

32618 concrete elements

2976 steel elements

690 rebar elements



3D Finite Element model

Parameter set:

o Anchorage length Le:

o Concrete class

1 m 1,1 m 1,25 m 1,5 m

C30 C40 C50 C60



Results and Discussions

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 1500

100200300400500600700800900

100011001200

Displacement [mm]

App

lied

load

[kN

]Concrete C30

Le = 100 cm

Le = 110 cm

Le = 125 cm

Le = 150 cm

Comment: The behaviour of the hybrid joints is unchanged when the

anchorage length Le > 1






0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 1500

100200300400500600700800900

100011001200

Displacement [mm]

App

lied

load

[kN

]Concrete C40

L

e = 100 cm

Le = 110 cm

Le = 125 cm

Le = 150 cm




0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 1500

100200300400500600700800900

100011001200

Displacement [mm]

App

lied

load

[kN

]Concrete C50

Le = 100 cm

Le = 110 cm

Le = 125 cm

Le = 150 cm






0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 1500

100200300400500600700800900

100011001200

Displacement [mm]

App

lied

load

[kN

]Concrete C60

Le = 100 cm

Le = 110 cm

Le = 125 cm

Le = 150 cm





Equivalent plastic strains (Le=1.1m and Concrete C40)

Plastic strain17/24 International Conference CIGOS Paris, 11-12 May 2015


Stresses (Le=1.1m and Concrete C40)

Stress18/24 International Conference CIGOS Paris, 11-12 May 2015


Results and Discussions The first yielding observed numerically is about the encased steel web panel in

tension



Results and Discussions Some plasticized zones are observed in concrete before reaching the yielding of

web panel in tension;

They are identified as "local" plasticization and not avoided in steel-concrete

structures.



Results and Discussions The second yielding observed numerically is at the stirrups;

The yielding of the stirrups probably results from the transmission of the

vertical applied force to the concrete column occuring at the interface contact

between steel beam lower flange and the concrete below.

It forms a "local strut and tie" mechanism in which two concrete struts start

from the lower flange to the longitudinal reinforcement and the stirrups play a

role of tie.



Conclusions A 3D finite element model has been developed to analyse the behaviour of new

type of exterior RCS joint subjected to static loading;

Material nonlinearities, interaction and the contact between steel and concrete

are taken into account.

The numerical results indicated if the encased steel profile is totally anchored

in RC column, the behaviour of the studied RSC joint is the one of steel joint (in

sense of Eurocode 3).

The failure mode firstly reached is caused by the bending moment transmission

from steel beam to encased steel column. As a result the concrete does not

affect much on the load value corresponding to this "steel joint" yielding.

The concrete contribution in the joint resistance starts to be activated when

"steel joint" yielding is reached and results in the hardening load-displacement

curves.

The numerical observation needs to be confirmed by the experimental one.



RCS Joint tested at UTC of VietnamCyclic test of RCS joint carried out at University of Transport and

Communications of Vietnam

December 2014



Thanks for your attention !

... any questions ?


Introduction3D Finite Element modelResults and DiscussionsConclusionsRCS Joint tested at UTC of Vietnam

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