UHPFRC in large span shell structures

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RILEM-y?ö-AFGC Int. Symposium on Ultra-Higli Perfonnance Fibre-Reinforced Concrete, UHPFRC 2013 - October 1 -3, 2013, Marseille, France

UHPFRC IN L A R G E SPAN S H E L L STRUCTURES

Richard N. ter Maten (1), Steffen Griinewald (2) and Joost C. Walraven (2)

(1) Mourik, Groot-Ammers, N L

(2) Delft University of Technology, Delft, N L

Abstract

Ultra-High Performance Fibre-Reinforced Concrete (UHPFRC) is an innovative concrete type with a high compressive strength and a far more durable character compared to conventional concrete. UHPFRC can be applied in structures with aesthetic appearance and higli material efficiency. Shell stmctures are spatially curved surface structures of which the exceptional behaviour can be referred to as 'form-resistant structures' which resist loads by developing stresses in its own plane. This paper describes the optimization process for the application of prefabricated rib-stiffened UHPFRC-elements. A spherical shell is designed with a span of 150 m and a height of 37.5 m. The designed prefabricated elements have a weighted mean thickness of 44 mm and a 'thickness over radius'-ratio of 2130, which is about 20 times more slender than an egg shell. The study shows that a large span shell structure produced with UHPFRC-elements is a promismg concept.

Résumé

Les bétons fibrés a ultra-hautes performances (BFUP) constituent une nouvelle gamme de bétons de résistance en compression élevée et de propriétés de durabilité bien supérieures a celles du béton ordinahe. Les BFUP peuvent être valorisés dans des ouvrages a enjeu esthétique et avec une recherche d'efficacité de l'emploi du matériau. Les structures de voiltes et coques sont constituées de surfaces courbes, dont le comportement spécifique peut être qualifié de "structures a résistance de forme", en effet elles résistent aux charges en développant des contraintes dans leur propre plan. Le présent article décrit le processus d'optimisation conduisant a 1'apphcation d'éléments préfabriqués en BFUP raidis. Une coupole sphérique est confue, avec une portée de 150 m et une hauteur de 37,50 m. Les éléments préfabnqués projetés ont une épaisseur moyenne pondérée de 44 mm et un ratio «épaisseur sur rayon» de 2130, soit environ 20 fois plus mince qu'une coquille d'ceuf L'étude démontre qu'une structure en voüte ou coque de grande portée constituée d'éléments en BFUP est un concept tout a fait prometteur.

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RILEM-y?è-AFGC Int Sympos^^^ Ultra-High Perfonnance Fibre-Reinforced Concrete, ÜHPFRC 2013 ^ October 1-3, 2013, Marseille, France

1. INTRODUCTION

1.1 Ultra-High Performance Fibre-Reinforced Concrete

with a ' S ? ' ' Fibre-Reinforced Concrete (UHPFRC) is a contemporary concrete

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1.2 Shell structures

Shell struchires (Table 1) are spatially curved surface stnichires which support extemallv r ï s Ï t f n t s t m t i r e s '

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öeliavioui. A shell can also fail due to material non-linearity, such as cracldng and crushing 01 by a combination of both non-linearity of geometry and material behaviour

2. OPTIMIZATION O F A S H E L L S T R U C T U R E

A study was carried out which combines both the potemial of UHPFRC with the structural and architectura, potential of shell stmctures. The design study and the c L T c f o f dim^^^^^^^

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RILEM-y?ö-AFGC Int. Symposium on Ultra-High Perfonnance Fibre-Reinforced Concrete, UHPFRC 2013 - October 1-3, 2013, Marseille, France

were based on a preliminaiy design for a project named 'Fiere Terp' by Maurice Nio (Nio architects) (Figure 1). This project was chosen because it is an existing shell design, open for an engineering solution and, as a first approximation, it can be modelled as a spherical dome. The recommendations for further design were developed subsequent to the initial design stage. The analysis included the calculation, the optimization and the consideration o f span to height-ratio; edge ring dimensions; element stiffening and configuration; lower-edge element thickness; connection requirements; dynamic response; thermal response.

2.1 Span to Height-ratio

Within the design for thin shell stmctures, with practicable proportions, the overall buckling capacity under vertical loading usually is the governing failure pattern over compressive strength as well as tensile strength. An intended span to height ratio of 4 was determined to be a feasible ratio for the material under consideration, the bearing capacity and the shell behaviour in circumferential direction (Figure 2).

Table 1: Survey of well-laiown shell stmctures [4]

Structure Year Geometry Dimensions Radius [a] Tliiclmess (t) Ratio (a/t)

Chicken Egg [-] 150*10'" B.C. Surface o f revolution 60 mm length 20 rmn minimum 0,2 - 0,4 mm 100

Pantlieon [Rome] 126 A . D . Hemisphere 43,3 m diameter 21,65 m 1,2 m at the top 24 Jena Planetarium [Germany] 1923 Hemisphere 25 m diameter 12,5 m 0,06 m 200 Jena Factoi-y [Gennany] 1923 Spherical cap 40 m diameter 28,28 m 0,06 m 470 Algecnas Market Hall [Spain] 1934 Spherical cap 47,6 m 44,1 m 0,09 m 490 Beer Can [-1 1935 Cylinder 66 m m diameter 33 mm 0,08 m m 400 Hibbing water filter plant [Minnesota] 1939 Ellipsoid o f revolution 45,7 m diameter 47,24 - 5,33 m 0,9-0,15 m 35 - 525 Bryn Mawr Factoiy [Pennsylvania] 1947 Elpar on a rectangular plane 19,6 X 25,3 m^ 25,0-32,9 m 0,09 m 300 - 400 Auditorium M I T [Cambridge] 1955 Segment o f a sphere on 3 points 48,0 m between supports 34,0 m 0,065 m 520 Kanehoe Shopping Center [Hawaii] 1957 Intersection o f 2 tori on 4 supports 39,0 X 39,0 m^ between supports 39,0 - 78,0 m 0,076-0,178 m 500- 1000 Palazetto dello Sport [Rome] 1957 Spherical cap with ribs 58,5 m diameter 30,9 m 0,12 m shell 0,33 m ribs 94 CNIT [Paris] 1957 Intersection of 3 cylinders on 2 supports 219 m between supports 89,9 - 420,0 m 1,91 -2,74 m total; 0,06 -0,12 m outer layers 47 - 153

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RILEM-y?è-AFGC Int. Symposium on Ultra-Higli Performance Fibre-Reinforced Concrete UHPFRC 2013 ^ October 1-3, 2013, Marseille, France

Figure 1: Preliminary Design 'Fiere Terp'

Figure 2: Buckling pattems under vertical loading (FEM-calculation, Scia Engineer) 2.2 Shell dimensions

The design aspects are combined for a final design of a spherical shell with a span of 150m and a height of 37,5m (Table 2), which was checked by Finite Element calculafions on various load cases.

Table 2: Design parameters Parameter Size / Weight Diameter [d] 150m Height [h] 37.5m

Radius 93.75m

Ai'ch length ~I74m Perimeter base ~470m Shell Surface ~22000m' Stnicture Weight 2485 ton

The shell structure (Figure 3) consists of 945 elements with an average weight of 2630 kg The UHPFRC-elements m the final design have a weighted mean thiclaiess of 44 mm (plate thiclmess. 35 mm and ribs: 60 x 180 mm'); the structure's slendemess is 2130 (ratio radius to element thickness). This means that the stmcture is far more slender than the shell structures displayed in Table 1. The smdy shows that the production of large span shell stmctures consisting of UHPFRC-elements is a promising concept

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RILEM-y?5-AFGC Int. Symposium on Ultra-Higli Perfonnance Fibre-Reinforced Concrete, UHPFRC 2013 - October 1-3, 2013, Marseille, France

d

Figure 3: Overall dimensions final design 2.3 Edge Ring

Since shell structures are 'form-resistant stmctures' a prestressed concrete edge ring is applied which has a significant effect on the ultimate buckling load. After performing Finite Element calculations it was concluded that the buckling load in an ideal support condition can be approximated with an edge ring with a pretension force of 3650 kN, of which the calculation was based on Barlow's formula for pressure on cylindrical shapes.

2.4 Prefabricated UHPFRC-elements

The shell consists of rib-stiffened elements; the ribs are applied to improve the inertia and result in a more efficient design and a thiimer average cross-section. For the design and the optimization of the shell elements a Finite Element analysis was applied. To optimize the ratio between the thin 'slab' of the element and its ribs multiple governing parameters were evaluated. Figure 4 shows results for the buckling load, the total weight of the stmcture as well as the correlation between the two aspects for an element thiclaiess of 60 mm and multiple configurations. It is shown that the positive effect of rib-stiffening is indubitable and the marginal benefit of increasing the rib thickness declines for a rib to slab thickness ratio larger than 5.

Buckling load [kN/m']

Total weiglit [MN] • Buckling load / Total Weight *100

0 60 120 180 240 300 360 420

Rib thickness t ( n r n i )

0 1 2 3 4 5 6 7

Rib to Slab Thickness ratio (-)

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mEM-y?Z,-AFGC Int Symposium on Ulna-Higla Perfonnance Fibre-Reinforced Concrete UHPFRC 2013 - October 1 -3, 2013, Marseille, France

d e s W H ï f ° allow comrecting the elements. For practical reasons all precast elements are r83 m ^

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^'^'^'^ ^'^f^'- ^'igh^y- A l l elements are

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(83 mm ovei 7.9 m length) to mcrease the bearing capacity of the shell. The size of ft

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- ^ i g h ' production preferences

c h l 1 i l f ' r ' ' f^J' ' P-duction with a steel mould w i chosen for its high accurate precision. An UHPFRC-element is shown in Figure 5

e.g. 2710 mm AA' 016 !20' 0 \a-7900 r ISO mm e.g. 3350 mm

Figure 5: UHPFRC-shell element 2.5 Connections

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'^^^P^^-^d ^vith regard to load introduction, assembly method, suitability foi UHPFRC, constmction speed, durability and provisions to be taken Two

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RILEM-y?Z)-AFGC Int. Symposium on Ultra-Higli Perfonnance Fibre-Reinforced Concrete, UHPFRC 2013 - October 1-3, 2013, Marseille, France

factors were decisive for the choice of the selected connection. Those are the fact that local force introduction can be realized with UHPFRC and the fact that immediate connecting is favourable to increase the construction rate. Local connectors demand local comiection facilities, which asks for provisions to be cast in UHPFRC. The provisions in the elements are designed based on provision principles commonly applied for tunnel engineering.

Reinforcement bar Anchor Gasket

Perpendicular Reinforcement

Connection Bolt

Figure 6: Cormection principle 2.6 Construction progress

The realization of shell structures, especially with slender UHPFRC-elements, can be challenging. The potential of the application of UHPFRC and material savings for the construction phase were investigated. The application of temporary support was found to be inevitable but the lightweight constmction with UHPFRC-elements shows a high potential for ease of constmction and a short constmction time.

In this study different constmction possibilities were considered concerning handling, erection, form -control and temporary supports during construction. It was concluded that the idea to coimect elements at ground level and subsequently place segments consisting of as many elements as possible per lift is most promising. Because of the light-weight design a crane can lift and place numerous elements in a single handling. The shell was divided in 36 radial segments and can be lifted up by one mobile crane. The segment itself is highly sensitive to deformations and it was therefore proposed to be lifted by an assisting stmcture.

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RILEM-y?è-AFGC Int. Symposium on Ultra-Higli Perfonnance Fibre-Reinforced Concrete UHPFRC 2013 - October 1-3, 2013, Marseille, France

3. C A S E STUDY: T R A N S F E R R I N G R E S U L T S

The main aim ofthe research was to optimize the preliminary design for the 'Fiere Teip' Within the case study the design for Fiere Terp was altered, with the assumption that hmdamental modifications were pennitted by the architect. The original design is based on the shape of a white water lily, as shown in the Frisian flag. The design was improved by stractural analysis and shape optimization. Multiple designs for Fiere Terp were discussed and improvements were proposed by deliberation of multiple variants and the preferences for the design based on the conclusions of previous discussed design considerations. The original design was improved by increasing the curvahire within the surface and around the edges. Also the surface was simplified to improve the structural behaviour as well as to promote element repetition and therefore production efficiency. Based on these refiections the most promising variant was chosen. The applied criteria were the positive structural behaviour as well as the resemblance to the initial architechiral shape and favourable element production.

Figure 8: Case Study; Original and Proposed Design 4. CONCLUSIONS

This paper discusses a study that combines the potential ofthe material UHPFRC with the stmctural and architectural potential of shell structures. It is demonstrated that the combination of UHPFRC and large span shell structures has a high potential. The most advantageous aspects of the design are the overall savings on material use and conesponding lower total weight of the shell which decreases the load on the foundation and edge ring, the weight for transport and the number of handlings. The most important recommendations are to cany out fiirther research and tests on the stmchiral behaviour of prefabricated concrete shells, especially on the effect of the joint design. It is demonstrated that the shell can be built with the exploitation of the durability aspects of UHPFRC with a lifespan of at least 50 years. R E F E R E N C E S

[1] Walraven, J.C, 'Designing witii ultra high strength concrete: basics, potential and perspectives'. Proceedings of international symposium on UHPC, Kassei, 2004!

[2] Hendriks, Ch.F.,'Duurzame Bouwmaterialen',/Eneas, 1999 (in Dutch).

[3] Leutbecher, T., Fehling, E., 'Stmctural Behaviour of UHPC under tensile stress and biaxial loading'. Proceedings of international symposium on UHPC, Kassei, 2004.

[4] Popov, E.P., Medwadowski, S.J., 'Concrete Shell Buckling', ACI, SP-67, Detroit, 1981

[5] Behloul, M., Ricciotti, R., Ricciotti, R. F., Fallot, P., Leboeuf, J., 'Ductal®'Pont du Diable footbridge, France', in Tailor made Concrete Structures, Wahaven & Stoelhorst eds CRC Press 2008.

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UHPFRC 2013

Proceedings of the RlLEM-fib-AFGC

International Symposium on Ultra-High Performance

Fibre-Reinforced Concrete

Edited by

Frangois TOUTLEMONDE

Jacques RESPLENDINO

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UHPFRC 2013

Proceedings of the RILEM-/t?7-AFGC International Symposium on

Ultra-High Performance Fibre-Reinforced Concrete,

1-3 October 2013, Marseille, France

E d i t e d b y Frangois T o u t l e m o n d e a n d Jacques R e s p l e n d i n o

" U H P F R C " international s y m p o s i u m was f i r s t organized i n Marseille

(France) i n 2009 f o r synthesizing the k n o w - h o w and applications related to

U l t r a - H i g h Performance Fibre-Reinforced Concrete (UHPFRC). Four years

later, projects and constructions u s i n g U H P F R C have d e f i n i t i v e l y gained a

g r o w i n g importance i n Europe and N o r t h America, as w e l l as i n Australia,

Far East, and especially Japan.

" U H P F R C 2013" has thus aimed at u p d a t i n g and complementing

experience gained i n the k n o w l e d g e and use of UHPFRC, based o n recent

practice of: design of b u i l d i n g structures, components, c i v i l w o r k s and

bridges; i n d u s t r i a l realizations (both o n site and i n precast factories); and

large-scale applications. M o r e than eighty presentations detailed the

technical and scientific advances, f o c u s i n g o n major recent realizations;

decisive use of UHPFRC i n structural r e t r o f i t t i n g and combination of

U H P F R C and o r d i n a r y RC; d u r a b i l i t y and resistance of U H P F R C under

severe on-site or laboratory conditions; prospective applications of

U H P F R C i n current or outstanding w o r k s ; recent advances i n U H P F R C

structures design and d u c t i l i t y assessment; and recent results of

constitutive characterization and m i x o p t i m i z a t i o n of UHPFRC.

I n 2013, Marseille, recognized as European capital of culture, has renewed

its u r b a n f i g u r e and shoreline w i t h iconic architectural achievements.

A m o n g them, the M u s e u m of European and Mediterranean Civilizations

( M U C E M ) constitutes an outstanding realization due to the systematic

structural and decorative use of UHPFRC. The M U C E M , i n hosting the

venue of UHPFRC 2013 s y m p o s i u m , has appeared as a symbol of

w o r l d w i d e engineering c o m m u n i t y , technical breakthrough and creativity.

R I L E M Proceedings PRO 87

ISBN: 978-2-35158-130-8

e-ISBN: 978-2-35158-131-5

2013 Edition

RILEM Publications S.a.r.1. 157 rue des Blains

F-92220 Bagneux - FRANCE

Tel; + 33 1 45 36 10 20 Fax: + 33 1 45 36 63 20 E-mail; dg@rilem.net

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RILEM meets these objectives through the work of its technical committees. Symposia, workshops and seminars are organised to facilitate the exchange of information and dissemination of knowledge. RILEM's primary output consists of technical recommendations. RILEM also publishes the journal Materials and Structures which provides a further avenue for reporting the work of its committees. Many other publications, in the form of reports, monographs, symposia and workshop proceedings are produced.

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Assessment of coupled thermo-mechanical behaviour of ultra-high performance p. 315 concrete columns in case of fire

Vérification du comporlement llieymo-inécanique couplé depoteaiix eu BFUP eu cas d'iuceudie Matthias SIEMON. Dieluiar HOSSER

Current and prospective U H P F R C applications: shells, building elements, p. 325 bridges, civil structures

Applications (les BFUP en coin s et prospectives : coques, composnnis de bailments, ponis, génie civil

UHPFRC in large span shell stioictures p. 327

Le BFUP dans des stvuctuyes de voiites et coques de grande portée

RichardN. TER MATEN, Steffen GRÜNEWALD, Joost C. WALRAVEN

CFRP tendons in UHPFRC - Bond behaviour and applications to folded and p. 335 curved shells

Cables composites a fibres de carhoue dans du BFUP - Adhérence et application daus des coques courbes ou repliées

Alexander STARK. Josef HEGGER

Fundamental study on construction systems for complete reuse using UHPFRC blocks p. 343

Etude d'un nouveau système constructif a partir de composants BFUP réutilisabies Hiroshi ITO, Tomoya NISHIWAKI, SuhuinKWON, Takatime KJKUTA

UHPFRC cladding for the Qatar National Museum p. 3 51

Bardage en BFUP pour le Musée National du Qatar Philippe MENETREY

UHPC in the U.S. highway infrastiTicture: experience and outlook p. 361

Le BFUP dans les infi'astruclures routières aux Etats-Unis : bilan et perspectives BenfaminA. GRAYBEAL

Trial construcdon of UHPC highway bridge p. 371

Réalisationpilote d'un pont routier en BFUP

Sung Yong PARK, Sung Tae KIM, Jeong Rae CHO, Jeong Woo LEE, Byung, SukKIM

Parkbridge : optimization of a slender bridge in UHPFRC p. 379

Parkbridge : optimisation d'un pont en BFUP uUra-élancé

Steffen GRÜNEWALD, Hans KÖHNE, Maurice NIO, Matteo SERAFINL Anja VERDONK, Rogier VANNALTA, Rob HUIJBEN, Viktor MECHTCHERINE, Lukasz DUDZIAK, Leo GIELBERT

Express bridge deck and light duty bridge p. 389

Tablier et passerelle Express YvesBRUGEAUD

FDN modular UHPFRC bridges p. 395

Fonts modulaires FDN en BFUP DU TIRIMANNA, Jan FALBR

An assessment of the steel fibre distribution to load bearing capacity of lost p. 405 shuttering slabs made from UHPFRC

Evaluation de la distribution des fibres en vue de la capacité portante de prédalles en BFUP Milan RYDVAL, Jiri KOLISKO, Miroslm' VOKAC, PeIrHUNKA