Australian Steel Institute 480 Queen St -...

Australian Steel Institute

480 Queen St – Case Study

Investor: Dexus

Developer: Grocon

D & C Contractor: Grocon

Architect: BVN

Structural Engineer: Aurecon

Steel Fabricators: PIC

Gay Constructions

Precision Steel

Lin-Eng

Steel Detailers: Steelcad Drafting

Beamline Drafting/

E-Fab Joint Venture

Contents

Introduction

Overview & Architectural Context

Structure Concepts & Principles

Structure Design

Construction Methodology & Program

Conclusion

Overview & Architectural Context

Brian Donovan

Principal, BVN

Structure Concepts & Principles

David Emery

Director, Emergent

Australian Steel Institute – 480 Queen St Case Study

Structural Concept & Principles

Overview

• 36 level office tower

(incl. 3 basements & 4 levels of

retail & mixed use)

• Office Floors – Innovative steel scheme

• Basements – fast precast solutions

• Major Jump Start (Gr to L4)

• 4030 floor to floor

(incl. 110 raised access floor)

• PCA Premium Grade

• 6 star Greenstar

• Active chilled beam



Innovative Steel Building

• ‘Parallel Beam’ (bearer-joist) framing

concept

• First full-scale use in an Australian office

tower

• 4,000 tonnes structural steel

• 68,000 m2 profiled steel sheeting

• First steel office tower in Queensland in

40 years

• Grocon selection of steel based on

speed of construction and holistic cost

efficiencies



Steel Scheme

• Bearer-joist, 2 layer, framing concept

• Efficiencies of continuity both directions

• 9 x 10.5/11,5m grid

• 530UB primary beams G300

• 410UB secondary beams G350

• Non composite – minimal shear studs

• Simple connections

• Minimal fabrication

• Maximum flexibility for services & future

proofing

• Nil notching or penetrating of beams



Framing Principles

• Parallel primary beams

(engineered for continuity)

• Non-composite secondary

beams – minimal shear studs

(engineered for continuity)

• Quick & safe release of beams

from crane

• Speed of erection



Scheme Benefits

• Simpler fabrication

• 50% less cleat plates

• 40% less welding

• 30% less bolting (8,000 less bolts)

• 90% (90,000) reduction in shear

studs & associated reinforcement

• Nil beam penetrations

• Simple beam connections

• Speed of erection

• Cheaper (10%)



Simple Connections

• Simple bearing connection of

secondary beams – 2 bolts

(no web stiffeners)

• Minimal fabrication

• Less crane time to erect secondary

beams

• Primary beams connected by plate

thru tube column and end plates to

webs

• Beam splicing by simple fin plates

at contraflexure



Typical Floor High-Rise

• 9 x 10.5/ 11.5/ 10.5m grid

• Continuous, eccentric, primary

edge beams – ‘bearers’

• 125 angle edge form &

stiffening



Typical Floor – High Rise



Structural Concepts


Structural Concept & PrinciplesBeam Connections – Splicing at Contraflexure



Connections – Beam to Beam


Structural Concept & PrinciplesBeam Continuity both Directions



Columns

• Concrete filled steel tubes

• Fire engineered – lightly reinforced

• Tube to tube connections bolted

every 2nd level – below slab level

– no site welding

• Single ‘thru’ plate for web

connection of primary beams.



Connections – Column to Column



Connections – Beam to Column



Connections – Joist to Bearer

• Single ‘thru’ plate to column for

end plate web connection of

primary beams

• Simple bearing connection of

secondary to primary beams:

- 2 bolts

- no web stiffeners



Fire Protection to all Beams



Typical Edge Condition



Floor Zone Section



Building Services Flexibility

Structure Design

Aaron Toscan

Associate, Aurecon

43

• Site Information

• Materials and Systems of Construction

• Focus on steel – working with Grocon

• Jump start

• Composite columns

• Design of typical steel office floors

• Floor vibration

• Podium / Ravine area

• Raking gardens

• Revit / Early Fabrication modelling

Discussion Points

44

Site Information

45

• Bound between Queen and Adelaide St approx 6m difference between street levels

• Built very close to boundary all around

• Lots of in ground street services to avoid

Site Information

• Particular complexity with

excavation close to Trustee

House (SW) and Collection

House (E), with it’s own

basement and core with

permanent ground anchors

abutting the boundary.

• High level weaker ground

toward the river end at

Queen St

• Strong weathered rock

typically at foundation level

– pad footings supporting

vertical structure

46

• Shotcrete walls and bored piered retention

• Basement precast shell beams and Hollowcore

• Columns: Insitu, composite concrete filled steel tube, precast

• Two way insitu PT flat plate podium slabs

• Traditional steel framed composite L4 jump floor

• Parallel beam ‘bearer and joist’ non-composite’ steel framed

typical floors

• Approximately 4000 tonnes of steel made up of approximately

2500 tonnes of universal sections, 500 tonnes of fabricated

beams and 1000 tonnes of tubular columns. The universal

sections typically come straight from One Steel in Brisbane

off the mill with only holes made.

Materials and Systems of Construction

47

NEED TO HAVE THE DESIGN COMPLETE EARLY

• Steel tendering process

• Pre-ordering of steel stock lengths

• Real focus on fine tuning the typical steel floors early

• Need to incorporate the impact of a lighter floor structure in

the vertical design

• Coordination of critical items

• Focus on one thing in design – Simplicity in design means

speed in construction!

Focus on steel - working with Grocon and team

48

Jump Start

49

• To expedite the steel framed floors in the tower, a jump start

system was used

• 18m columns cantilevered from Ground floor up to Level 4

• Cantilevered steel jump tubes ranged from 1100 dia to 800 dia

• Jump tubes filled by pumping a high slump mix from the base

• No temporary bracing / propping was required for the jump

• Level 4 traditional in plane steel floor was erected and poured

in zones

• Steel corbels were welded in the shop to the jump columns for

Mezz, L2 and L3 to be constructed later

Jump Start

50

Jump Start

51

Jump Start

52

• Columns above ground level are

typically concrete filled steel

tube columns designed to EC4

• Tubes Gr250 ranging from 1100

dia to 550 dia at the top

• No fire treatment to the column

• Lightly reinforced concrete

column, designed for the fire

load. Reinforcement installed in

shop

• Concrete grades ranging from

N65 to N40

• Typically erected as a double

height column

Composite Columns

53

Composite Columns

54

Design of typical steel floors

• Twin parallel primary beams –530UB82’s spanning 9m. Gr300

• Continuous 410UB54 secondary beams at 3m ctrs. Gr350

• Non-composite due to continuity. Only nominal shear studs at 2m crs for lateral restraint and transfer of diaphragm forces

• Beams spliced at points of contraflexure – very sensitive

• Floors beams generally dictated by strength, specifically for the negative hogging moment

• Single primary edge beam –minimise push/pull reversal actions

55

• 530UB+410UB = 940mm constant

structural steel zone. For some

longer spans or larger loads, this

meant fabricated beams

• Separation of twin primary beams

consistent up building. Only

stepping in once up the building with

the reduced column size

• Good integration with in ceiling

services

• Steel beams typically designed using

SpaceGass


56

• Connections premised on simplicity with none or little

fabrication. ie. Bolt holes only in beams!

• Consideration of out of balance pattern loading

• The column through plate supported vertical loads, as well

as a proportion of horizontal column restraint loads


57

• No web stiffeners! Beam web buckling utilisation was around

90% typically

• Connections typically designed using Limcon and inhouse

spreadsheets


58

• Reviewed floor performance against Steelwork Construction

Institute (SCI P354) and AISC Design Guide

• 480 Queen St team targeted a response factor (R) of 4 - 6 max

• R = multiplier on the level of vibration at the average threshold

of human perception

• We used Oasys GSA for finite element modelling of dynamic

floor performance

Floor Vibration

59

Floor Vibration

60

Podium and Ravine Areas

• Complex floor geometry from

Mezzanine to L4

• Incorporates Ravine through

link, light voids, artwall, raking

gardens

• Profile of the jump start was

determined considering

complexities

• Use of these floors was mainly

retail and plant

61


62

• Due to the non-standard geometry, a two-way PT flat plate was

used supported on a steel corbel welded to the column

• Limited access to the underfloor area made the use of this

insitu system appropriate


63

Raking Gardens

64

Raking Gardens

65

Raking Gardens

66

• Prior to the steel Tender process,

Grocon engaged a shop detailer

to generate a fabrication

equivalent 3D model

• The detailer co-located into

Aurecon’s office

• Aurecon imported relevant info

into the Revit Structural model

• Confidence in design

• Coordination

• Highlight detailing gaps

• Reduced RFI’s

Revit / Early Fabrication Modelling

Construction Methodology

& Program

Scott Thomson

Project Manager, Grocon

CONSTRUCTION METHODOLOGY & PROGRAM

• Construction Methodology Overview

Structural Steel Columns and Floor Framing, Metal Deck Formwork, Reinforced Concrete Slabs

Post Tensioned Precast Concrete Shell Beams and Hollowcore Planks

Structural Steel ‘Jump Start’ Framing, In-situ Concrete Formed Slabs Beneath


• Program Overview

2013 2014 2015 2016

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2

Possession of Site / Commencement of Construction

Excavation

Structure

Facade

Base Build Finishes

29 April 2013 18 Nov 2013

25 Oct 2013 1 August 2015

28 Oct 2014 11 Sept 2015

19 Jan 2016

Practical Completion10 Feb 2015

29 April 2013

20 Nov 2014

Notes:Program based on 6 day working week

Includes 11% Delay Allowance

Original Program (conventional) = 35 monthsForecast Structural Steel Time Saving = 2 monthsContract Program = 33 months


Precast Shell Beams and Hollowcore Planks


‘Jump Start’ Steel (Ground to Level 4)

- 18m high

- 1000mm diameter tubes

- Self compacting concrete

- Pumped from base

- Podium infill slabs

CONSTRUCTION METHODOLOGY & PROGRAM‘Jump Start’ Steel (Ground to Level 4)

Jump Start Column Lifters Jump Start Hold

Down Bolts

CONSTRUCTION METHODOLOGY & PROGRAM‘Jump Start’ Steel (Ground to Level 4)

Pumping self-compacting concrete from column base



Metal Tray Formwork Installation


Parallel Beam Steel – Typical Floors

Self-climbing concrete placing boom / perimeter screens


Parallel Beam Steel – Typical Floors

Typical SL92 mesh / minimal shear studs


Perimeter self-climbing screens


Screen hold down bolts / façade bracket cast-ins


Jumpform hanging platforms / core cleats


Metal formwork loading


Level 14 transfer beams


Primary to column connection


Prefabricated reo cages


Access – Steel vs Conventional Formwork


• Considerations:

• Design – lead time

• Fire spray containment

• Crane time requirements

• Building type suitability (commercial offices)

• Restricted loading zones in CBD

Structural Steel – Considerations


• Advantages:

• Safety (nil lost time injuries to date)

• Speed of construction

• Reduced site labour

• Simple construction

Structural Steel – Advantages


Slabs currently at Level 32 = 4 weeks ahead of program

Construction Status

Conclusion

Concluding Remarks 1 of 2

• Innovative steel framing scheme

• Conceived for economy, simplicity and

speed of erection

• Successful first full-scale use in an

Australian office tower

• First steel office tower in Queensland in 40

years

• Excellent Safety achievement – zero steel

MTI’s & zero Project LTI’s

Concluding Remarks 2 of 2

• Speed – 4 wks ahead of contract program

(that was previously adjusted 8 wks for steel

structure), plus includes for 5 wks absorbed

against delay allowance that increased from

11% to 16% = 4 mths acceleration total.

• Holistic cost benefits

• Structure top-out scheduled 1st week July

• Successful R & D for future steel projects.

Australian Steel Institute 480 Queen St -...

Documents

Transcript of Australian Steel Institute 480 Queen St -...