European Project Fire Resistance of Innovative and Slender Concrete Filled

Tubular Composite Columns (FRISCC)

Logo of the University /

Company

Dr.-Eng. Gorka Iglesias

Grupo CONDESA

Behaviour and Design of

Tubular Joints

Unfilled and Filled

OUTLINE

FRISCC - Fire Resistance of Innovative and Slender Concrete Filled Tubular Composite Columns

1. INTRODUCTION

2. JOINTS IN COMPOSITE STRUCTURES

3. DESIGN OF JOINTS

Behaviour and Design of Tubular Joints – Unfilled and Filled

FRISCC

R&D Manager – Grupo CONDESA

• Funded in 1954

• Tube manufacturers

• 8 Companies in Europe

• Welded tubes / Cold drawn tubes / Open profiles

• Cold formed & Hot finished Structural Hollow Sections

Φ = 17,2mm to 508mm

t = 1,5mm to 16mm

INTRODUCTION

www.condesa.com

FRISCC

TC Chairman – CIDECT (International Committee for the Development and Study

of Tubular Construction)

• Funded in 1962

• Association of tube manufacturers worldwide

• Technical Commission, Promotion Committee, Executive Committee

• TC composed of CIDECT Members and Experts (from renowned Universities,

Research Centres and Companies)

• 200 Research Projects

• Books and Design Guides

• Software

• Cooperation with ECCS, IIW, AISC…

INTRODUCTION

www.cidect.com

OUTLINE

FRISCC - Fire Resistance of Innovative and Slender Concrete Filled Tubular Composite Columns

1. INTRODUCTION

2. JOINTS IN COMPOSITE STRUCTURES

3. DESIGN OF JOINTS

Behaviour and Design of Tubular Joints – Unfilled and Filled

FRISCC

Structures behave as they are built, not as they are designed!

• Joints are key elements

JOINTS IN COMPOSITE STRUCTURES

FRISCC

Structures behave as they are built, not as they are designed!

• Joints are key elements

JOINTS IN COMPOSITE STRUCTURES

FRISCC

Structures behave as they are built, not as they are designed!

• Joints are key elements

JOINTS IN COMPOSITE STRUCTURES

FRISCC

Structures behave as they are built, not as they are designed!

• Joints are key elements

JOINTS IN COMPOSITE STRUCTURES

FRISCC

Structures behave as they are built, not as they are designed!

• Joints are key elements

JOINTS IN COMPOSITE STRUCTURES

source: 20minutos.es

FRISCC

In composite structures, joints must be analysed carefully:

• They constitute the load entry to a column

• They can contribute (or spoil) the composite behaviour of the column

Different ways to contribute the composite behaviour of the column

• To rely on bond strength typical max. tRd = 0,40 N/mm2 (to be revised?)

• To assure physical contact

JOINTS IN COMPOSITE STRUCTURES

FRISCC

JOINTS IN COMPOSITE STRUCTURES

To be careful because the joint behaviour could change in fire situation:

• The concrete filled column (and the joint) can be externally protected.

• The concrete filling can be used as the fire protection.

Anyway, the important thing is to have a consistent design!!! (Any decision in

design has a consequence in the structural behaviour)

OUTLINE

FRISCC - Fire Resistance of Innovative and Slender Concrete Filled Tubular Composite Columns

1. INTRODUCTION

2. JOINTS IN COMPOSITE STRUCTURES

3. DESIGN OF JOINTS

Behaviour and Design of Tubular Joints – Unfilled and Filled

FRISCC

For the design of beam-to-column joints, the methods for unfilled columns are

used as a basis. It is important to notice that some joints can change their

behaviour when the columns are filled (in comparison with the analogous unfilled

one):

• The concrete filling of the column prevents inward deformation of the column

face.

• This face will therefore act as a very stiff part.

• The stiffness of connections with concrete filled columns

is roughly two times that of the unfilled counterparts.

• In most cases, the typical column face plastification failure

of unfilled columns is not governing the strength criterion of

filled column joints, but punching shear.

DESIGN OF JOINTS

FRISCC

For the design of beam-to-column joints, the methods for unfilled columns are

used as a basis. It is important to notice that some joints can change their

behaviour when the columns are filled (in comparison with the analogous unfilled

one):

• The concrete filling of the column prevents inward deformation of the column

face.

• This face will therefore act as a very stiff part.

• The stiffness of connections with concrete filled columns

is roughly two times that of the unfilled counterparts.

• In most cases, the typical column face plastification failure

of unfilled columns is not governing the strength criterion of

filled column joints, but punching shear.

DESIGN OF JOINTS

FRISCC

As a consequence of all the previous reasons, several connections, which with

unfilled columns behave as semi-rigid (partial strength) connections, after filling

with concrete behave as rigid (partial strength) connections.

A reduced deformation or rotation capacity has a consequence that the

connections are more sensitive to secondary bending moments.

More research is needed, mainly on the connections’ stiffness.

On the whole, it could be said that the filling of concrete provokes a change in the

behaviour of some of the join ‘components’ comparing to the unfilled configuration.

CIDECT is developing a Project (16F): COMPONENT METHOD FOR TUBULAR JOINTS

consisting on the development of a full consistent design approach for bolted and

welded hollow section joints.

DESIGN OF JOINTS

FRISCC

CIDECT Project 16F – COMPONENT METHOD FOR TUBULAR JOINTS:

• Unified approach for design of steel (and composite) joints.

• To cover more types of joint configurations in trusses and building frames.

• To cover more types of (bolted and welded) connections.

• Combination of hollow sections and open sections.

DESIGN OF JOINTS

FRISCC - Fire Resistance of Innovative and Slender Concrete Filled Tubular Composite Columns

FRISCC

THANK YOU VERY MUCH

FOR YOUR ATTENTION!

Behaviour and Design of Tubular Joints – Unfilled and Filled