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Design of High Performance Steel Reinforced

Concrete Composite Structures using Eurocode 4 Approach

Chiew Sing-Ping

Professor of Civil Engineering

SINGAPORE INSTITUTE OF TECHNOLOGY

12 June 2019

Outline of Presentation

▪ DfMA Innovative Technologies for Industrial Buildings

▪ HPSRC Structural Framing System

▪ Challenges Facing Us

- Design Issues

- Availability of Welding Consumables

- Cost of Materials

▪ Concluding Remarks

Changing the way we build……...

Design for manufacturing and assembly (DfMA)

➢ A key strategic thrust to raise construction productivity.

➢ Construction designed and detailed for a substantial portion of work to be done

off-site in a controlled manufacturing environment

Innovation

TechnologiesGame-Changing

Technologies

High Strength Composite

Steel Concrete StructuresPPVC

Multi-tier / Pre-assembly

Steel Components

Prefabricated Steel /

Reinforcement / Formwork

Components

Steel

PPVC

Continuum of Technologies for DfMA

Composite Steel Concrete

Structures

JTC Logistics Hub @ Gul

Source: JTC & Kimly Construction Pte Ltd

Source: Seoul National University, Korea (2015)

Prefabricated Steel Reinforced Concrete (PSRC)

Column & T-Type Steel Concrete (TSC) Beam System

Composite Structural Framing System with

Composite Transfer Beams

Source: Tsinghua University, China (2017)

Source: Xi’an University of Architecture & Technology, China (2018)

Partially Precast Steel Reinforced Concrete

Structural Framing System

High Performance Steel Reinforced Concrete

(HPSRC) Composite Structural Framing System

• High Strength Materials (C90/105 +

S690 +GR600)

• Pre-Engineered Built-Up Sections

• HP Steel Reinforced Concrete (SRC)

Composite Structural Framing

System

• Hollow Core Slab / T-Beam with

Concrete Topping

Boosting productivity by

adopting DfMA in design

SRC main beam with HISTEEL690,

GR600 rebar and C90 concrete

SRC secondary beam

Pre-engineered Precast SRC main beam

Pre-engineered Precast SRC secondary beam

Details at Beam-Column Junction

Details at Beam-Column Junction

Precast T-beam flooring system

Precast T-beam flooring system

Precast T-beam flooring system

16

Multi-Storey Bus Depot (Source: LTA)

Integrated Bus-Rail Depot (Source: LTA)

JTC Logistics Hub (Kimly Construction)

Heavy Industrial Buildings (Source: JTC)

Applications of HPSRC System

Design Issue – Strength Limitation of EC4

The ranges in EC4 are more restricted than EC2 and EC3, the

question is WHY?

• Lack of test data and experience in composite design with high

strength materials

• Strain compatibility problem

EC2 EC3 EC4

Concrete C90/105 _ C60/75

Reinforcing Steel 600 N/mm2 _ 600 N/mm2

Structural Steel _ 690 N/mm2 460 N/mm2

Example of projects

adopting BC4: 2015

BCA-NUS enhance Eurocode 4 to allow higher

strength steel (up to S550) and concrete (up to

C90/105) for the design of composite CFT

columns. What about SRC columns?

(To be launched in 2019)

Innovations in Composite Steel-Concrete Design

Concrete Filled Tube (CFT)

Columns with High Strength

Materials - An Extension of

Eurocode 4 to C90/105

Concrete and S550 Steel

Design of SRC Columns using HISTEEL690

Published 4 April 2018

Ref: SP Chiew & YQ Cai (2018). Design of high strength steel reinforced concrete columns – a Eurocode 4 approach. Steel

Construction 11, No. 4, 2018, Ernst & Sohn Verlag, Berlin, Germany.

SRC Column using

HISTEEL690

Structural

Framing System

Benefits of SRC Columns using HISTEEL690

UC356x406x287

C50/60

S355

UC356x406x287

C90/105

S355

UC356x358x153

C90/105

S690

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

1 2 3

AcAaAs

Am

ou

nt (T

on

)

NSC+NSS HSC+NSS HSC+HSS

Column cross section reduced by 36%

Weight of steel section reduced by 47%

Modified Eurocode Confinement Model

For SRC column, concrete confinement can be provided by the lateral links

(PCC) and steel section (HCC).

How to predict the stress-strain behavior of confined concrete in SRC columns?

Confinement zones in SRC columns

Partially

Confined

Concrete

Highly

Confined

Concrete

Design Issue – Effect of Welding on S690Q

Investigation on the effects of welding and mechanical behavior of S690Q

S690Q

Welded High

Strength

Steel Section

- ‘HISTEEL’

QA&QC of S690Q Pre-Engineered Sections

Fabrication of S690Q pre-engineered sections in controlled environment:

❖ To adopt higher productivity welding techniques such as semi-auto SAW

❖ To precisely control the welding parameters and quality

Design Issue – On Site Welding of S690Q

EN 1993-1-12: Additional Rules to EN1993-1-8

4.2(2): For steel with grades greater than S460 up to S700 the filler

metal may have lower strength than the base material.

4.7.1(1): The resistance of welded connections with under-matched

electrodes with steel grades greater than S460 up to S700 should

be based on the strength of the filler metal.

or

FCAW - Reinforced

full strength

penetration butt

weld

Design Issue - Limitation of Concrete Cover

Design Solution: use built-up sections which are more flexible to meet the concrete cover limits

tw

tf

bc

cycy b

cz

h

cz

hc

Limit of concrete cover :

• y-direction: 40 mm < cy < 0.4 b

• z-direction: 40 mm < cz < 0.3 h

EN1994-1-1 Cl. 6.7.3.1(2)

SRC column with HISTEEL690,

GR600 rebar and C90 concrete

Benefits of HISTEEL690:

- more efficient section design due to

maximum concrete cover (cy & cz) limits

- Lesser rebars required, lesser congestion

at beam-column junction

Erection of multi-tier

‘cruciform’ columns

Concluding Remarks

• EC4 has been extended to cover a higher range of material strength

up to S690Q steel, Design guidance is available.

• We derive greatest benefit from high strength materials when our

design are NOT governed by stiffness, i.e. deflection, buckling,

vibration or other service requirements, for e.g. stress or crack width

limit.

• For this, composite construction is most ideal and S690Q can be used

for plunge-in kingposts and HPSRC framing systems for heavily-

loaded industrial and commercial buildings because the potential

benefits are enormous.

• We should consider using S690Q and move forward confidently.

Thank You for your Kind

Attention !