recent advances in high performance steel and composite steel … · 2019-07-18 · this paper...

The University of Sydney

Recent Advances in High Performance Steel and Composite Steel Structures in Australia

Presented byProfessor Brian UyHead of SchoolSchool of Civil EngineeringThe University of Sydney

Regency Steel Asia Symposium on Innovative Research, Advanced Design & New Construction Technologies on Steel and Composite StructuresWednesday, 12 June 2019


Abstract

This paper addresses the applications, behaviour and construction ofhigh performance steels in steel-concrete composite structures. For thepurposes of this paper, high performance steels will include high strength,stainless and weathering steels. Akin to many innovations in theconstruction industry, high performance steels have generally beenadopted for the use in iconic projects well before design procedureshave been developed in standards. This paper will provide a summaryof many of the applications particularly as they pertain to iconic projectsin Australasia and internationally. Recent research in these areas willalso be summarised and important design parameters as they deviatefrom traditional mild structural steel will be highlighted. Australasianadvances in the standardisation of both bridges and buildingsincorporating high performance steels will also be summarised, withparticular reference to the Australasian Design Codes in Bridge Structures,ASNZS 5100 Part 6; and Building Structures ASNZS 2327 which haveboth been published in 2017. The paper will conclude with suggestionsfor further research and will identify areas of significant gaps inAustralasian and international standards which will also guide futureresearch in this area.


Applications, behaviour and construction of high performance steels in steel-concrete composite structures

– Introduction– Applications– Research– Codes of practice– Conclusions and further research– Acknowledgements– References


Introduction

Modern infrastructure demands higher performance, which inmany cases is achieved through the improved strength anddurability of the structural materials. Future bridges will demandlonger and more durable spans and future buildings will alsodemand taller heights and reduced maintenance.


Introduction

High strength steel has had some significant previous usesinternationally. The benefits of high strength steel are principallyin the reduced structural weight and area derived from their use.The juxtaposition of the use of high strength steel together withconcrete can remedy many of the disbenefits that are oftenassociated with high strength steel. The use of higher strengthsteels often means sections are more susceptible to local, globaland coupled instabilities for a similar strength section to a mildstructural steel member. Serviceability is often seen as beingmore controlling for a high strength steel flexural member whencompared to a similar strength mild structural steel beam, howeveroften the use of precambering can alleviate these issues.Furthermore, with increasing use of high strength steels in longspan structures, prestressing is often employed to overcome thereductions in stiffness.


Introduction

Stainless steel is being considered more prominently internationallyin large scale iconic structures. Initially, the use of stainless steelswas largely driven by architectural requirements in majorprojects, however the more recent innovations in stainless steeltechnology and the reduced costs has certainly seen stainlessstructural steels become cost competitive for structures in durabilitydriven environments where whole of life cycle analysis can assist inthe financial justification.


Introduction

Weathering steels are a much more recent innovation in the highperformance steel area, however have a very similar architecturaldrive to stainless steels and one finding particular favour inAustralasia and internationally.


Applications

Previous applications for many high performance steel structuresinternationally have been in steel-concrete composite forms. This ismainly since the cost differential of high performance steel overmild structural steel has required some sort of innovation tocompensate for this. This section will highlight some of thesesalient examples for high strength, stainless and weathering steels.


Applications – High strength steel

– High strength steel applications in Australia have beenprevalent for three decades and ultimately have shaped thedirection of future Australian Standards in Steel-ConcreteComposite Construction, [1,2].



One of the first and most iconic of buildingprojects in Australia to adopt the use of highstrength quenched and tempered structuralsteel was the Grosvenor Place, completed in1988. This building designed by therenowned architect, the late Harry Seidler,maximises the Sydney Harbour views over44 floors and a total height of 180 m withan elliptical core, as illustrated in Fig. 1. Thisbuilding incorporated the use of highstrength quenched and tempered structuralsteel in the basement columns. High strengthsteel encased columns were utilised in thebasement levels to group perimeter steelcolumns on the façade and to minimise thesize and number of columns in the basement.This had the benefit of maximising thenumber of car spaces per level of car parkand thereby reducing the significantexcavation costs through high strengthSydney sandstone, [3].



Star City (now known as the Star Sydney)upon completion in 1995 was the secondlargest building construction project in areato be completed in New South Wales sincethe Sydney Opera House, as illustrated inFigure 2. The project included two majortheatres, two towers (both residential andhotel), as well as the main casino gamingfloors and other entertainment venues.Located in an extremely confined part ofSydney, the project employed the design ofhigh strength steel trusses to minimisecraneage requirements on site. These trusseswere made composite with topping slabs andpost-tensioned, further reducing the steelweight requirements. In addition the buildingalso utilised the use of high strength steelencased composite columns to minimise thearea of columns in the basement carparklevels, [4].



Latitude is an iconic steel and compositecommercial building over 45 floors and 222metres in height and which was completed in2004, [5] as illustrated in Fig. 3. The buildingadopted some novel forms of steel and compositeconstruction. These included long span pre-cambered composite beams, twin tube columns filledwith high strength concrete and some very largehigh strength steel transfer trusses, which wereinfilled with concrete. These transfer trusses wereincorporated to allow the building to cantileverover the pedestrian level areas and take greateradvantage of the air space toward the westernedge of the building. The use of high strengthsteel box trusses allowed the minimisation ofweight and thereby did not impact too greatly ononsite craneage requirements. The filling of thesebox trusses by concrete infilling on-site ensuredthat the truss members could be made compositewith the high strength steel plates.



Internationally, on completion Taipei101 in Taipei, Taiwan (Fig. 4) was theworld’s tallest building. Completed in2004, it remained the tallest buildinguntil 2011 when the Burj Khalifa inDubai was completed. This building isover 500 metres tall, with 101 stories inone of the most seismic regions of theworld. From a construction innovationperspective this building achieved somesignificant firsts, including the use of highstrength concrete up to 80 MPa and theuse of high strength steel up to 600MPa. This was deployed in the largescale box columns used as mega-columns for both the gravity and lateralload resisting system of the building onthe perimeter, [6].



Completed in December 2016and opened in early 2017 theLotte Tower in Seoul, South Koreareaches skyward to over 550 mover 123 floors. It is currently the5th tallest building in the world.The building has been designedwith the use of high strength ofabout 600 MPa yield stress and800 MPa ultimate stress, [7]. Theuse of high strength steel inexterior mega-columns also utilisedthese for both the gravity andlateral load resisting systems.



The previous applications both Australian and internationally haveillustrated that the use of high strength steel, coupled withconcrete is assisting structural engineers to push the barriers instructural building heights. As urbanisation continues to increasearound the world, there will be an increasing demand for the useof high strength steel, as this will helpful in providing the solutionsto many of these future iconic projects. Materials advances,particularly in the mechanical and automotive industries for evenhigher strength steels up to 1000 MPa ultimate stress, may furthercontribute and assist in solutions for tall buildings and longer spanstructures, [8].


Applications – Stainless steel

Stainless steel structural applications can provide significanteconomy when one considers the whole of life cycle costs of astructure. Stainless steel although significantly more expensive thancarbon steel, has the benefits of significantly reducedmaintenance. Furthermore, the mechanical and fire resistance ofstainless steel is far superior to carbon steel. The benefits can befurther enhanced by the juxtaposition of stainless steel withconcrete to further improve the local, global and coupledinstabilities of stainless steel-concrete composite structures.



Stainless steel structuralapplications have once againfocussed on many previous iconicprojects. The Gateway Arch in StLouis, Missouri completed in 1965consisted of a 192 m arch andwas designed by the renownedarchitect Eero Saarinen, [9]. Thestructural concept essentially is adoubled skinned compositestructural tube with a stainless steelcladding, so essentially non-structural.



The flagpole of the ParliamentHouse in Canberra wascompleted in 1988 in time forthe Australian Bicentennialcelebrations and is a verylarge structure, rising 81 metresand weighing some 250 tonnes,as illustrated in Fig. 5, [10].



Hearst Tower in New York ,illustrated in Fig.6 used stainlesssteel boxed clad columns for theexternal diagrid lateral loadresisting system, [11].



The Stonecutters Bridge in HongKong with a 1018 metre spanwas the longest cable stayedbridge in the world uponcompletion, [12]. The bridgeconsists of two 290 metre tallmasts with their upper thirdcomprising of a stainless steelsection filled with concrete.


Applications – Weathering steel

Weathering steels like stainless steels have the significant advantageof providing superior corrosion resistance and thereby cansignificantly reduce maintenance costs. Once again these need toconsidered in whole of life cycle costing of structures. Weatheringsteels are also very much associated with the architectural designof a structure and preferred in iconic structures. They howeverhave quite a different paradigm and are diametrically theopposite of the shiny and new aestethic that stainless steel creates.Weathering steels convey an already corroded look and appearmore rustic/used. They have however been used in somesignificant examples of Australian iconic structures, namely theAustralia Pavilion at the World Expo in Shanghai in 2010, [13]and in the more recent use in a Deakin University footbridge in2017, [14].



Australia Pavilion at the WorldExpo in Shanghai in 2010, [13]



Deakin University footbridge in2017, [14].


Research

The previous sections have highlighted that many of the previousiconic projects using high performance steels, have involved verylarge cross-sections, with most of these needing to be fabricatedthrough conventional welding techniques. The large volumes ofresearch related to steel or steel-concrete composite structureshave often dealt with very thin steel sections, often fabricatedfrom fairly light welding techniques. Also, many of the researchprojects on tubes have been carried out on cold formed tubes, whichhas many beneficial effects when compared with large fabricatedpolygonal sections which may be adversely affected by residualstresses and geometric imperfections which arise from heavilywelded sections.


Research – High strength steel

When using high strength steel, like all high performance steels,the benefits that can be derived from juxtaposing steel withconcrete need to be optimised so that the initial capital cost outlayof a more costly fabricated structure can be offset by significantbeneficial effects.



Uy [15 and 16] clearly outlinedthe benefits for short columnssubjected to both axial andcombined actions. With thesetwo studies the improvedslenderness limits over non-composite high strength steelsections was outlined.



Mursi and Uy [17] furtherhighlighted the benefits ofusing high strength steel inslender composite columns. Thisstudy illustrated that one couldoptimise the column curve beingused in slender column designand this was principally as aresult of the reduced level ofresidual stress as a function ofthe member yield stress.



Mursi and Uy [18 and 19]further considered the effectsof biaxial bending of highstrength concrete filled steel boxsections. This set of studies wasparticularly useful inhighlighting the conservativenature of existing designprovisions for biaxial bendingand how the effects of materialnon-linearity can be used tofurther optimize the behaviourand design of these members.



More recently, Khan and Uy etal. [20 and 21] furtherextended the work in the areaof high strength steel toincorporate the effects of highstrength concrete of 100 MPacompressive cylinder strength.Their studies considered boththe effects of short and slendercolumns.



Khan et al. [22] also conductedone of the first studies on theeffects of welding residualstresses on thick steel plates. Platethicknesses of 16 mm wereevaluated with multiple passwelding. The results of this studyshowed that previous studies on theeffects of welding residual stresseson thinner plate steels may not beapplicable to heavier weldedsections and thus caution may benecessary in looking at this in thecontext of high strength steel usedin practical projects.



Whilst significant research has beencarried out on the behaviour of highstrength steel in composite columns,there has been some research in thepast that has focused on thebehaviour of composite beams withhigh strength steel sections. Uy andSloane [23] carried out a series oftests and developed a numerical modelto evaluate the strength of a full andpartially shear connected beam. Banet al [24] carried out furthernumerical studies to assess therotational behaviour of high strengthsteel-concrete composite beams.


Research – Stainless steel

Stainless steel is typically significantly more costly than carbonsteel, primarily because of the introduction of nickel and chromiumwhich has the significant benefits of improving the corrosionresistance of the material. Optimisation for the use of stainlesssteel can be made by the beneficial effects that concrete has indelaying local and global instabilities. Stainless steel like otherhigh strength steels also has the benefit of providing confinement toconcrete for a much larger range of strains than carbon steel, [25].



Significant research by Uy etal. [26] and Tao et al. [27] hasshown the benefits that concreteinfill provide both short andslender concrete filled steelcolumns.



Recent research, consideringconnections of stainless steel byHasan et al. [28] also assists tounderstand how entire structurescan be designed using stainlesssteel.

There is a need to avoid thesetting up of sacrificial anodesby the use of mixed materials.


Research – Weathering steel

At this stage, there does not appear to be any significant researchthat has been carried out in this area.


Codes of practice

Over the last five years, two major projects have been ongoing inAustralasia to develop revised design guidelines for bridges,ASNZS 5100, Part 6, [1] and buildings, ASNZS2327, [2]. Thesetwo design standards reflect the latest international developmentsin steel-concrete composite construction and also are unique asthey incorporate design requirements for the highest strengths forconcrete and steel internationally. These two standards allow forthe design of steel-concrete composite structures with concretecompressive strengths up to 100 MPa and steel yield strengths up to690 MPa.


Conclusions and further research

This paper has broadly outlined the area of the applications,behaviour and design of high performance steels in steel-concretecomposite structures.

It is clear from the nature of the applications that highperformance steels will have greater applicability in iconicprojects. It is with these types of projects that standard sized coldformed and hot rolled sections are of limited applicability. Thesetypes of projects require large plate thicknesses and heavilywelded sections are often required to form up the different typesof cross-sections required. These types of structures have veryparticular types of methods of manufacture, which have nottraditionally been researched in the area of steel or steel-concrete composite structures.



In assessing further research, it is clear that high strength steel beamshave been considered, however would have fairly limited applicability.The behaviour of high strength steel-concrete composite infilled orencased columns have also been very well researched. Further researchappears to be needed in the area of larger thickness plate sections, inparticular to assess whether there are any through thickness or sizeeffects associated with sections incorporating multi pass welding. Otherfurther work could be carried out in the area of high strength compositeconnections as the larger loads that are being transferred would bemore efficiently transferred through connections incorporating higherstrength elements, such as bolts, plates and welds.

Very high strength steel up to 1000 MPa is also being produced by platemanufacturers internationally. With the constant drive to taller buildingsand larger span structures, higher strength steels can also assist toprovide appropriate solutions for the future. The evaluation of plateslenderness limits, the assessment of short and slender column behaviourfor columns composed of these types of materials will also be veryvaluable for the future.



Previous research in the area of stainless steel composite members hasfocused entirely on cold formed stainless steel members. There has beensome preliminary work being carried out into the behaviour offabricated stainless steel members. There is a need to carry outresearch into fabricated stainless steel sections made composite withconcrete and covering the areas of beams, columns and connections.The assessment of plate slenderness limits and the consideration ofresidual stresses and geometric imperfections for large plate thicknessesis considered an important aspect for future applications and design ofthese structures.

Weathering steel has potential for many future applications,particularly in Australia, where the rustic aesthetic appears to blend inwith natural landscapes. It appears that bridge infrastructure couldhave the greatest application. It is definitely considered necessary tocarry out studies into the static and cyclic composite capacity of bridgegirders incorporating steel girders with weathering steel.


Conclusions and further research- High Strength Steel Sections


High Strength Steel Sections

0

0.2

0.4

0.6

0.8

1

1.2

0 20 40 60 80 100

be/b

Lamda_e

Hollow box sections

AS4100-HW

AS4100-LW

0

0.2

0.4

0.6

0.8

1

1.2

0 20 40 60 80 100 120 140

be/b

Lamda_e

Filled box sections

AS4100-HW

AS4100-LW


High strength steel sections

0

0.2

0.4

0.6

0.8

1

1.2

0 10 20 30 40 50

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Hollow I sections

AS4100-HW

AS4100-LW

0

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0.6

0.8

1

1.2

0 10 20 30 40 50 60 70

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Filled I sections

AS4100-HW

AS4100-HW


Conclusions and further research- Very High Strength Steel Sections


Conclusions and further research- Stainless steel sections


Conclusions and further research- Stainless steel sections

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0.4

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0.8

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1.2

1.4

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0.8

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1.4

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1715

13

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5

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7

2

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Hollow

Filled

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-F

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AS2327 AS4100 (0.65)

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Acknowledgements

The author would like to acknowledge the support of theAustralian Research Council which is supporting the ongoing workin this paper through the awarding of the following two DiscoveryProject Grants, DP170100001, “Coupled service and ultimatebehaviour of high strength composite columns”, andDP180100418, “Behaviour & design of large fabricated stainlesssteel composite structures”. Ongoing experimental research iscurrently being funded through these two project grants.


References

1. Standards Australia AS/NZS 5100.6: Bridge design - Steel and composite construction, Australia, 2017.

2. Standards Australia ASNZS2327-2017, Composite structures - composite steel-concrete construction in buildings, 2017.

3. Grosvenor Place, URL: https://en.wikipedia.org/wiki/Grosvenor_Place_(Sydney), accessed 27/04/18.

4. Star City, URL:https://en.wikipedia.org/wiki/The_Star,_Sydney, accessed 27/04/18.5. Latitude, URL:https://en.wikipedia.org/wiki/Latitude_(building), accessed 27/04/186. Taipei 101, URL:https://en.wikipedia.org/wiki/Taipei_101, accessed 27/04/18.7. Lotte World Tower URL:https://en.wikipedia.org/wiki/Lotte_World_Tower, accessed

27/04/18.8. Ishii, T., Fujisawa, S. and Ohmori, A. Overview and application of steel materials for

high-rise buildings, JFE Technical Report, No 14, 2009.9. Gateway Arch URL:https://en.wikipedia.org/wiki/Gateway_Arch, accessed 27/04/18.10. Parliament House URL:https://en.wikipedia.org/wiki/Parliament_House,_Canberra,

accessed 27/04/18.

https://en.wikipedia.org/wiki/Grosvenor_Place_(Sydney)

https://en.wikipedia.org/wiki/The_Star,_Sydney

https://en.wikipedia.org/wiki/Latitude_(building)

https://en.wikipedia.org/wiki/Taipei_101

https://en.wikipedia.org/wiki/Lotte_World_Tower

https://en.wikipedia.org/wiki/Gateway_Arch

https://en.wikipedia.org/wiki/Parliament_House,_Canberra


References

11. Fortner, B. Landmark reinvented, Civil Engineering Magazine, ASCE, 76(4): 42-49, 2006. 12. Vejrum T., Bergman, D. W. and Yeung, N. Stonecutters Bridge, Hong Kong: Design and construction of the composite upper tower in

stainless steel, Nordic Steel Construction Conference, Malmo, Sweden, 351-358, 200913. Taylor, A, Australia on Show, Steel Profile No 106, 2010.14. Anon. Steel bridge goes above and beyond: Deakin University Burwood Link, Steel Australia, 26-27, December, 2017.15. Uy, B. Axial compressive strength of short steel and composite columns fabricated with high strength steel plate. Steel and Composite

Structures, 1 (2), 171-185, 2001.16. Uy, B. Strength of short concrete filled high strength steel box columns. Journal of Constructional Steel Research, 57(2), 113-134., 2001. 17. Mursi, M., Uy, B. Strength of slender concrete filled high strength steel box columns. Journal of Constructional Steel Research, 60 (12),

1825-1848, 2004.18. Mursi, M., Uy, B. Behaviour and design of fabricated high strength steel columns subjected to biaxial bending: Part I :

Experiments. Advanced Steel Construction: an international journal, 2(4), 286-313, 2006.19. Mursi, M., Uy, B. Behaviour and design of fabricated high strength steel columns subjected to biaxial bending: Part II : Analysis and

design codes. Advanced Steel Construction: an international journal, 2(4), 314-354, 200620. Khan, M., Uy, B., Tao, Z., Mashiri, F. Behaviour and design of short high-strength steel welded box and concrete-filled tube (CFT)

sections. Engineering Structures, 147, 458-472., 2017. 21. Khan, M., Uy, B., Tao, Z., Mashiri, F. Concentrically loaded slender square hollow and composite columns incorporating high strength

properties. Engineering Structures, 131, 68-89, 2017. 22. Khan, M., Paradowska, A., Uy, B., Mashiri, F., Tao, Z. Residual stresses in high strength steel welded box sections. Journal of

Constructional Steel Research, 116, 55-64, 2016. 23. Uy, B. and Sloane, R.J. Behaviour of composite tee beams constructed with high strength steel, Journal of Constructional Steel Research 1

(46), 203-204, 1998.24. Ban, H., Bradford, M., Uy, B., Liu, X. Available rotation capacity of composite beams with high-strength materials under sagging

moment. Journal of Constructional Steel Research, 118, 156-168, 2016.25. Uy, B. Stability and ductility of high performance steel sections with concrete infill. Journal of Constructional Steel Research, 64(7-8),

748-754, 2008. 26. Uy, B., Tao, Z., Han, L. Behaviour of short and slender concrete-filled stainless steel tubular columns. Journal of Constructional Steel

Research, 67(3), 360-378, 2011.27. Tao, Z., Uy, B., Liao, F., Han, L. Nonlinear analysis of concrete-filled square stainless steel stub columns under axial compression. Journal

of Constructional Steel Research, 67(11), 1719-1732, 2011.28. Hasan, M., Ashraf, M., Uy, B. Moment-rotation behaviour of top-seat angle bolted connections produced from austenitic stainless

steel. Journal of Constructional Steel Research, 136, 149-161, 2017.


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