pentadome

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Detailing and Construction of

the PantadomeRoof Structurefor a Bullring in Xtiva (Spain)Carlos Lzaro1,*, Alberto Domingo2

1Departamento de Mecnica de Medios Continuos y Teora de Estructuras2Departamento de Ingeniera de la Construccin y Proyectos de Ingeniera Civil

[email protected]

Universidad Politcnica de Valencia

Camino de Vera s/n

46022 Valencia (Spain)

(Received April, 19, 2010 - Revised version September, 6, 2010 - Acceptation October, 2, 2010)

ABSTRACT: This paper describes the detailing and construction of a roof

structure for a bullring in Xtiva (Spain). The roof has been built by means of

a new version of the Pantadome system. The roof dome is spherical shaped

with a 42 m diameter central opening and an exterior diameter of 101,6 m. It

is supported on 44 columns distributed along a 86,4 m diameter circumference.

The structural system is formed by radial truss lattices pinned to the columns

and to the inner ring and supported by the action of an outer tension ring, radial

tension members and tension (upper chord) and compression (lower chord) in

the inner ring. The structure was built near the ground and lifted by shortening

44 radial strands with jacks attached to the inner ring. Strand forces have been

transferred to permanent tension members at the end of the process. Thekinematics of the deployment has been analyzed. Forces in the jacks have been

obtained theoretically from the kinematics and compared with the measured

values. Special details, developed for the attachment of the jacks and the force

transfer are described. The development of the lifting process together with the

results of the geometrical survey show that the new erection system allowed

the construction of the dome in a quick and safe way.

Key Words: roof dome structure, Pantadome system, structure detailing,

construction method, heavy lifting, deployment control, force transfer.

1. INTRODUCTION

The bullring arena in Xtiva (Spain) is a historicalbuilding which was designed by the architect

Demetrio Ribes (18771921). Modern (s. XIX and

XX) bullrings in Spain (called plazas de toros) are

generally uncovered, near-circular buildings with the

arena in the center and the grandstand enclosing it.

Bigger bullrings are closed by two or more levels of

covered boxes, which were not present in Xtiva. The

eldest part of Xtivas arena was built in 1917,

consisting of 12 rows of grandstand seats supported

by 44 brickwork radial walls, around a 49,5 m

diameter arena. After a stop caused by financial

International Journal of Space Structures Vol. 25 No. 4 2010 229

difficulties, the construction was resumed and ended in

1919: the radial masonry walls were extended usingasymmetrical arches and 12 more grandstand rows

were built on them, reaching an outer diameter of

77,5 m. The building remained however unfinished.

The outer view showed the plain unornamented

brickwork of the walls with niches prepared to allocate

structural members for a future extension. Fig 1 shows

an overall view of the historical building. The

principal feature and historical value of the building

rests on the grandstand seats: they are I or L shaped

beams being one of the first examples of pre-cast

reinforced concrete elements in Spain (Fig 2).*Corresponding author: [email protected]

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Because of the very limited number of bullfightingspectacles in the year, public administrations tend to

devote bullrings to a number of different events in order

to have a profitable use of such buildings. With this

purpose, the municipality of Xtiva released in 2005 a

tender with the aim to restore, enlarge and cover Ribes

building. The tender was won by the construction

companyLlanera with the design proposed and developed

by the authors together with Prof. Mamoru Kawaguchi.

Reference [1] contains details about the conditions of the

tender, the motivation of the architectural proposal and

the renovation of the old construction. Fig 3 shows anoverall view of the finished works.

The main feature of the design is the construction of

the roof by means of a new kind of Pantadome with no

temporary supports designed by M. Kawaguchi. The

Pantadome system for the erection of large roof

structures is a well known procedure which has been

developed by him. It is based on the idea of

temporarily transforming the roof in a one-degree-of-freedom mechanism during construction, by taking out

a number of structural members. The structure (and

even parts of the cladding) can be assembled near the

ground and pushed up acting on the unconstrained

direction. Once the target position has been reached

the system is stabilized by installing the remaining

members. The detailed description of the Pantadome

procedure can be found in reference [2]. Several

realizations have been also described in [2], and in

references [3], [4] and [5].

This paper describes the structural solution ofXtivas arena roof with emphasis on the special

construction process and the necessary devices and

details of the structure which have been specially

developed for the new Pantadome. The outline of the

paper is as follows: the next section describes the

structural system of the enlarged parts of the building

and the roof. The third section shows the kinematics

of the special Pantadome used for the erection of the

dome. The fourth section describes the structural

details of the system. The fifth section reviews the

construction sequence focusing on the lifting up ofthe structure and the last section summarizes the

conclusions.

2. STRUCTURAL SYSTEMIn order to preserve the historical value of theplaza, it

was decided to keep as many existing stands as

possible by building the lower ring of the new

grandstand above the existing, simply letting the new

lower row seats to rest on the radial masonry walls. To

enlarge the spectators capacity an upper grandstand

ring (enclosing the existing one) and the intermediateaccess floor (level +7,20 m) were designed. The upper

ring extends from elevation +9,75 m to +15,25 m with

an outer diameter of 80 m. The structure for the new

seats serves also the purpose of supporting the new

roof, which is spherical-shaped, covers the stands,

cantilevering a few meters to the outside and leaving

free space above the arena. It is ring shaped in plan

with 101,6 m outer diameter and 42 m inner diameter,

and the sphere is 160 m radius. Fig 4 shows the two

rings of stands under construction and Fig 5 displays

the typical cross section of the building after theenlargement.

230 International Journal of Space Structures Vol. 25 No. 4 2010

Detailing and Construction of the PantadomeRoof Structure for a Bullring in Xtiva (Spain)

Figure 1. Bullring Arena of Xtiva in 1919

Figure 2. View of the original RC grandstand

Figure 3. Overall view of the roof

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Carlos Lzaro, Alberto Domingo


Structural system of the roofThe structure of the roof works as a wheel system

(Figs 6 and 7) composed by (a) an inner 42 m indiameter trussed ring (with upper compression chord

and lower tension chord), (b) 44 radial lattice girders

grouped and braced in pairs, (c) an outer 86,4 m

diameter tension ringjoining the column heads and

the lattice girder outer vertexes, and (d) radial tension

membersjoining the lower vertex of the girders with

the lower chord of the inner ring. The membrane

action of the roof is achieved by the bracings between

paired girders and by an inner bracing ring joining the

connections between girders and the upper chord.

The upper and lower chords of the 8 m deep innerring are HEB600 curved members. They are restrained

by vertical hollow profiles and U-shaped diagonals.

Radial lattice girders are shaped by the curved upper

chord (550 mm double T section), and lower chords,

posts and diagonals formed by a variable number of

30 70 mm plate members, CHS1404, CHS1645 and

HEB160 members connected by pin-joints; the upper

chords cantilever to the outside of the building.

HEB300 members form the outer tension ring. The

lower radial tension members are double 30 70 mmplate members.

The whole roof system lies on 44 HEB240 columns.

They are connected to the lower part of the structure

by means of hinges. Lateral forces are resisted and

transmitted to the lower structure by cross rod bracings

between columns.

Table 1 shows the member forces due to the self-

weight of the roof structure and to all permanent loads

in the main structural elements.

Structural system of the stands and floorThe main issue concerning the lower part of thestructure was to design a system with no interaction

with the existing construction. The upper stands ring

and the floor are supported by a spatial rigid framed

structure. The main determining factor was to avoid

structural interaction with the historical construction;

moreover, the position and number of columns should

allow for the necessary free space for users and solve

Figure 4. New stands under construction

Floor level

Ground level Masonry wall

Lower stands ring

Lattice grider

Outer ring

Column

Tension memberUpper stands ring

Inner ring

Figure 5. Typical cross section

Lattice girders

Inner ring

Outer ring

Columns

Braces

Figure 6. Structural system of the roof

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the problem posed by the need of the +7,20 floor to

reach the top of the lower stands ring, stretching

between the existing walls with no structural contact.

The construction (Fig 8) is supported by two groups

of columns: (i) a group of 44 outer columns aligned

with the radial masonry walls and distributed along acircumference of radius 43,2 m and (ii) a group of 47

inner columns located between masonry walls and

distributed along a circumference of radius 32 m

(clearance in the three entrance spans requires

duplication of the columns, hence the difference in

the number of them). The columns in each group are

connected by rectangular box girders at the

intermediate floor level and at the upper stands ring

top and bottom levels. Horizontal loads transferred

from the roof are resisted by local bending of the top

part of the columns and by the ring action of the upperbox girder ring.

Radial beams connected to the box girders support

the floor level. They are grouped in three units for each

cantilever between radial walls: two are next to the

walls and the third is located in the middle. The stands

are also supported by radial members with the

necessary slope. The inner lines of the upper stands

and the cantilevering floor are connected by a trussed

ring. Loads on the floor between walls are transferred

by cantilever action to the box girder rings; they areresisted by bending and torsion of the box girders.

Columns are S355J0H CHS 406,2 12,5 mm, box

girders are S275J0H RHS 400 200 16 mm. The 120

mm thick composite floor deck is made with C25/30

concrete on a folded plate. Transverse beams are

IPE400 (variable to IPE260 for cantilevering parts).

3. KINEMATICS OF XTIVASPANTADOMEXtivas Pantadome system has been designed as

follows:(a) The vertical movement of the inner

compressiontension ring is unrestrained. This

freedom is permitted by the temporary absence of

(i) outer ring members between lattice girder

pairs, of (ii) other circumferential members

between lattice girder pairs and of (iii) the inner

bracing ring.

(b) Movements along the free direction require three

groups of hinged connections with fully permitted

rotations: the bases of the roof columns are hinged

to the top of the lower structure supports; the topof the roof columns is hinged to the outer lattice



Figure 7. Finished roof structure

Table 1. Roof member axial forces for permanent loads in kN (finished structure)

Inner ring

Load case Roof columns Outer ring Upper chord Lower chord Radial members

Self-weight 121 26 990 1 081 156

Permanent loads 213 188 1 147 1 719 250

Figure 8. Lower spatial structure

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girder joints, and the inner joint of the lattice

girders is hinged to the upper chord of the inner

ring. The three pairs of hinges, corresponding to a

pair of columns and lattice girders, share parallel

axes; they are perpendicular to the radial bisector

plane of the lattice girder planes.

(c) During the deployment the following parts of thestructure move as rigid solids: (i) the inner

trussed ring travels along the vertical direction,

(ii) the 22 pairs of braced lattice girders travel

and rotate around their hinged joints, and (iii) the

22 pairs of braced columns supporting the girders

rotate around their hinged bases.

In the final position every lattice girder and the

corresponding radial tension member are located in a

vertical radial plane. This is, however, not the case in the

starting position, due to the fact that the lattice girders

are rotated in pairs, and to the orientation of the rotation

axes. In this initial position, girders are not contained in

vertical planes and the provisory tension members are

not coplanar to the girders. The angular deviation was

considered negligible and was not considered in the

design of the deployable system details.

The special feature in Xtivas Pantadome system is

the absence of temporary vertical jacks. Instead of

using vertical jacks to push up the inner ring, the

movement was achieved by shortening 44 radial

tension members that connect the lower lattice joints

with the lower chord of the inner ring. The movement

is schematized in Fig 9. The total weight of the

structure during the lifting was 4 530 kN.

The inner ring travels 16,868 m upwards and the

length dof the radial members is shortened in 5,33 m.

Along this movement the supporting columns rotate

(angle ) from an inward inclination of 21,3 (from

the vertical) to a vertical position, with a maximum

outward inclination of 3,4 in an intermediate position.

The pitch of the truss girder (angle between the

horizontal and the plane joining external hinge lines of

the truss girder) varies from 31,3 to 11,6. The

kinematical relationships can be explicitly represented

as functions of . The expressions include the

following representative dimensions: the column

height a = 7,80 m; the girder length between hinges 2b

= 22,66 m and the girder depth c = 4,22 m; the innerring depth h = 8 m, and the horizontal distance

between column hinges and the inner ring r= 22,2 m.

Eqn 2 and 3 provide the variable length d of the

tension members and the elevation z of the upper

chord hinge (see Fig 10left).

(1)

(2)

(3)

Fig 11 shows the angles and the upward travel as

functions of the length decrease of the tension members

obtained from the above expressions.

Since the (common) length of the strands controls

the kinematical freedom of the Pantadome system, the

evolution of the jack forces during the lifting can be

represented as a function of the strand shortening from

a virtual work calculation. Assuming that the weights

of the structure are applied at the lattice girder extreme

hinges n and m (Wn = 62,5 kN and Wm = 46,9 kN),the virtual work of the weights over the variation of

the elevation of the hinges plus the virtual work of the

strand tension Tover the variation of the strand length

dmust vanish (refer to Fig 10right):

(4)

From Eqn 3,

(5) z an = sin

=T d W z W zn n m m 0

z a b= +cos sin 2

d b c h b c h2 2 2 2

2= + + +( sin cos )

sin ( cos ) / = 2b r a

3 4

1 2

Figure 9. Deployment of the Pantadome. Cross section

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(6)

Using Eqn 1 and 2, the variations and can be

written as functions ofd.

(7)

(8)

Therefore,

(9)

Fig 12 shows the resulting tensile forces as

functions of the shortening of the strands, and table 2

Tbd

h c bW Wn m=

+

+

2

( sin cos )(( )

sin tan

WWm cos )

2 2 2d d bh ch = + cos sin

cos sin = 2

b

a

z a bm = + sin cos 2

summarizes the axial forces in the main members of

the Pantadome mechanism at the beginning and the

end of the deployment.



n

2b

dh

c

a

m

Wm

Wn

Zm

Zn

T

T

d

Figure 10. Parameters of Xativa's Pantadome system (left) and forces and virtual displacements (right)

18

16

14

12

10

Upward

trave

l(m)

8

6

4

2

0

0 1 2 3Shortening of strands (m)

4 5 6

20

10

0

10

Ang

les

(degrees

)

20

30

40

50

0 1 2 3Shortening of strands (m)

4

5 6

Figure 11. Evolution of the upward travel (left) and the angles (right) vs. strand shortening

280

260

240

TheoreticalMeasured

220

200

Jack

force

(kN)

180

160

140

1200 1 2 3

Shortening of strands (m)

4 5 6

Figure 12. Evolution of the jack forces

(theoretical and measured)

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4. DETAILING OF THE PANTADOMEThe decision of building the structure by means of the

Pantadome method required a special design of some

connections and members of the roof. Fully rotational

hinges have been already mentioned. Additional

questions were posed by the active members which

were to be shortened and their connection to the lattice

girders and the inner ring. The first idea was to use

these members not only as temporary elements but

also as definitive structural members. This possibility

was strongly conditioned by the available lifting

system and procedure.

After studying some proposals it was decided to lift

up the Pantadome using post-tensioning strands and

jacks. The necessary materials and the control of the

process were commissioned to the company VSL. The

VSL post-tensioning system is composed by groups of

high-grade steel 7-wire strands, anchor blocks, anchor

wedges and pulling jacks. The system is originally

designed for post-tensioning of concrete elements. For

such applications strands are allocated inside a hull

which is filled with a protecting mortar, and the anchor

blocks are elaborated trumpet-shaped devices with

inner deviator and anchor plates, the whole system

being designed to be cast into the concrete element.

However in a lifting application the system is reduced

to a minimum: merely the bare strands, anchor plates

and wedges are present. The system is thus completely

unprotected and the design of a durable protection is

complicated and uneconomical. For this reason the

original idea was disregarded and it was decided to

transfer the loads to permanent steel double- 30 70 mm

plate members after the lifting had been completed.

Therefore, the lifting would be achieved by means

of 44 jack units located and distributed along the inner

side of the lower chord of the ring, each jack acting on

four strands provisory anchored to the lower joints of

the lattice girders. In the design of these joints both the

provisory anchorages for the strands and the jacks, and

the connections for the permanent members had to be

considered.

Special pieces were pinned to the lower joints of the

lattice girders, consisting of two side plates provided

with holes for the pin-connection of the permanent

members (distance between pin centers equal to

610 mm), and one intermediate perforated thick plate

to thread the strands and accommodate their anchor

block, transversely welded to the side plates. During

the lifting process these pieces directly transmitted the

tension in the strands to the lower joints of the lattice

girders, being thus collinear to the strands (Fig 13).

After completion of the lifting process, variable

distances between the joints to which the plate

members should be pinned were to be expected, due to

imperfections and tolerances of the system. To absorb

these differences, a short rod (310 mm between pin

centers) connected to the lower chord joint in the inner

ring was designed: after the Pantadome has reached

the target position every permanent member should

be pinned to each short rod; the tensioned strand, the

permanent plates and the short rods forming a triangle

before the transfer. At the target position, the elevation

Table 2. Roof member axial forces due to the self-weight in kN (Pantadome system)

Inner ring

Roof columns Outer ring Upper chord Lower chord Radial members

Starting position 119 1 514 1 264 241

Final position 103 880 909 131

Figure 13. Anchor joint at the truss girder. Lifting situation (left) and permanent situation (right)

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of the inner ring should be slightly higher than the

design elevation, so that the distance between joints

for the permanent members should be smaller. In this

way the permanent members could be joined to the

special pieces at the lattice girder joints and to theconnecting rod with enough tolerance, and they would

be put in tension by releasing the tension in the jacks.

Finally, the permanent members and the short rods

would be tensioned and aligned.

Nevertheless the tolerance was limited to a rather

narrow range (considering the overall dimensions) by

the geometry of the system. The sum of the lengths of

the special anchor piece, the permanent double plate

and of the short rod (referred to the centers of the pin

joints) determines the maximum allowable distance

between pins: 610+

9 454+

310=

10 374 mm. Theminimum distance was conditioned by the fact that the

short rod could, at most, rotate 47 (measured from the

line of strands) making no contact with the lower flange

of the lower chord, being equal to 10 273 mm (Fig 14).

The joint at the lower chord has to accommodate a

number of elements leading to a non-trivial

arrangement (Fig 15). It is located into a square

opening (conveniently stiffened) in the web of the I-

member. It consists of (i) a hinged perforated block to

allow for the threading of the strands and their rotation

during the lifting process, (ii) the short rod formed by

two plates pinned at the sides of the block, (iii)

provisory elements for the attachment of the jack. The

weight of the jack (15 kN) posed an additional

problem: as the jack rotates during the deployment, it

has to be bolted to the hinged block (i). To avoid local

bending of the strands, a special deviator piece to be

attached to the inner side of the hinged block wasdesigned. The set formed by the deviator, the hinged

blocks and the jack works as a rocking lever. Once the

strands are in tension, the weight of the jacks is

balanced by a transverse force acted on the deviator by

the strands. In this way, stresses due to bending of the

strands are negligible. This piece was formed by two

830 mm long rectangular plates joined by a perforated

transverse plate, and was dismantled together with the

jack anchoring pieces once the strands were removed.

5. CONSTRUCTION SEQUENCEAssemblyThe lower part of the structure was erected from January

to August 2006. Between August and November 2006

the intermediate floor and the stands were completed.

Roof assembly began in December 2006. Firstly the

inner ring was assembled on 44 provisory concrete

blocks (2 m high). Then the 22 pairs of lattice girders

and the corresponding pairs of columns were connected

to the upper chord of the ring and to the column heads

(Fig 16). All these operations were performed with the

help of two automobile cranes and several pneumaticplatforms in a safe near-ground position. With the

positioning of the jacks and the threading of the strands,

the assembly of the basic Panta was completed on

February 20, 2007. At this stage the structure was

prepared for the deployment (Fig 17left).

LiftingThe 44 jacks had a capacity of 1050 kN and could

safely deliver a pulling force of 700 kN. They were

grouped in four sectors (see table 3). All jacks in a

sector were serially connected and pressurized by one



10.273

9.4540.610

0.610

0.310

0.31

0

47.00

10.374

9.454

Figure 14. Kinematics of the force transfer system

Figure 15. Lower chord joint at the inner ring. Jack and strands (green), jack anchor pieces and deviator (red), permanent tension

members and short rods (blue), and hinged block (grey)

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compressor. The machines were commanded from a

central control located in the arena. Each compressor

could be operated simultaneously or individually. The

stroke of each jack was equal to 140 mm, with which

the inner ring could travel about 0,54 m (this value was

variable due to the progressive change in the

geometry) (refer to the diagram in Fig 11). 39 strokeswere needed to complete the whole travel.

The lifting sequence was as follows: The Pantadome

was detached from the temporary supports (lift off) on

the evening of February 23, 2007 (Fig 17right). On

February 24 the structure travelled 8,7 m upward in 19

strokes. The operation was resumed on February 25

and ended after 20 additional strokes. Figs 18 and 19

show inner and outer views of the deployment.As mentioned in the previous section, the estimated

pulling forces during the lifting process follow a

decreasing sequence from 241 kN at the starting

position to 139 kN at the target geometry. The

detachment of the first support took place with 67% of

the project force (162 kN) and the complete lift off of

the structure needed about 109,5% of the project force

(263 kN). The difference can be put down to

readjustments of the structural system and friction in

the joints. The paradoxical steep fall of the forces led

in some isolated case to the slackening of one of thefour strand units. Fig 12 shows the measured forces in

Detailing and Construction of the Pantadome roof structure for a bullring in Xtiva (Spain)

Table 3. Lifting sectors and control radii

Sector Jack denomination No. of units

A1 J1 to J6 6

A2 J7 to J12 6

B J13 to J22 10C1 J23 to J28 6

C2 J29 to J34 6

D J35 to J44 10

Figure 16. Assembly of truss girders

Figure 17. Jacks in lifting position and lower chord just after the lift off

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The first item was controlled by the travel of a thread

attached to the jack going to and returning from a

pulley located at the anchor of the strands (VSL own

system). The second and third items were measured

using classical topography. Geometrical surveillance

was made every two strokes at the beginning (up to

stroke number 6), and then every four strokes (the

sequence can be followed in table 4).

The evolution of the geometry of the inner ring can

be followed in Figs 20 (vertical geometry) and 21

(planimetry). The diagrams in Fig 20 show thedifferences between measured upward travels and

the jack versus the strand shortening. The difference

between theoretical and measured values is kept into

the range of 0 to 10 % along the whole process. Force

values were obtained from the values of the oil

pressure at the compressor equipments. Table 4

summarizes the measured values of the representative

variables during the process.

A geometrical control of the lifting process was

carried on. The following items were inspected at 8

radii during the deployment: (i) shortening of the

strands, (ii) elevation and planimetry of the upperchord, (ii) elevation and planimetry of the lower chord.

Figure 18. Lifting sequence (inner view)

Figure 19. Lifting sequence (outer view)

Table 4. Measurements during the lifting sequence

Stroke no. Shortening avg. (m) Upward travel avg. (m) Jack force avg. (kN)

lift off 0,014 0,055 262,50

2 0,290 1,079 227,28

4 0,575 2,126 195,13

6 0,851 3,104 182,44

10 1,415 5,018 166,03

14 1,973 6,816 155,53

18 2,534 8,576 148,97

19 2,573 8,707 151,38

23 3,133 10,416 146,34

27 3,695 12,117 147,22

31 4,255 13,791 143,94

35 4,816 15,443 141,75

38 5,236 16,647 137,59

39 5,374 17,039 136,60

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their average value at eight control points at each

representative step or stroke. Fig 21 shows the

differences between radial coordinates of the control

points and their average. All values are relative to the

initial geometry (prior to the lift off).At the beginning of the lifting process the distortion

of the vertical geometry of the ring showed a rapid

increase (Fig 20left). After stroke number 18 the

difference in the z coordinate between control points 3

and 5 went beyond 0,1 m. It was then decided to

correct the geometry of the ring by pulling 20 mm with

jacks J1 to J22 (sectors A and B) and 60 mm with jacks

J23 to J44 (sectors C and D); this operation is referred

to as stroke 19 in the diagrams. The resulting vertical

geometry, with a difference of less than 0,08 m

between points 3 and 5, was satisfactory. The rest of

the strokes up to the no. 39 caused much smaller

vertical distortions with z differences lower than 0,1

m (Fig 20right). Concerning the changes in the radius

of the inner ring, Fig 21 shows a similar pattern as for

the vertical geometry. The correction stroke causes aslight improvement of the geometry and the distortion

decreases as the target geometry is approached. It has

to be mentioned that due to the position of the

topographic stations on the arena, the accuracy of the

measures decreased as the inner ring traveled upwards.

End of the liftingThe target position of the structure was determined by

the final geometry. In this situation the theoretical

distance between tension member pins should be

equal to 10 374 mm (plate length equal to 9 454 mm).After the last stroke the real distance between pins to

install the tension members should lie in the interval

[10 273 mm, 10 374 mm] (see previous section). To

determine the magnitude of the last stroke, distances

between pins at the 8 control radii after stroke number

38 were measured, with an average value equal to

10 454 mm. A target average value of 10 316 mm was

fixed, corresponding to an angle of 35 between the

short rod and the strands. Therefore, the last stroke

Table 5. Position of control points and radii

Control radius Jack no. (deg.)

1 J5 44,8

2 J10 3,8

3 J16 44,94 J21 85,9

5 J27 134,9

6 J32 176,7

7 J38 225,8

8 J44 266,0

0.08

0.06

0.04

0.02

Differencebetweenzandaveragez(m)

0

0 50 100 150

coordinate (deg.)

200 250 300 350

Stroke 18Stroke 19

0.02

0.04

500.06

0.08

0.06

0.04

0.02


0

0 50 100 150

coordinate (deg.)

200 250 300 350

Stroke 19Stroke 23Stroke 27Stroke 31Stroke 35Stroke 39

0.02

0.04

500.06

0.08

0.06

0.04

0.02


0

0 50 100 150

coordinate (deg.)

200 250 300 350

Lift offStroke 2Stroke 6Stroke 10Stroke 14Stroke 18

0.02

0.04

500.06

Figure 20. Evolution of the vertical geometry of the inner ring. From lift off to stroke no. 18 (left), situation after the correction

stroke (center) and from stroke no. 19 to stroke no. 39 (right)

0.06

0.04

0.02

R

referredtotheoriginalgeometry(m)

0

0 50 100 150

coordinate (deg.)

200 250 300 350

0.02

0.04

500.06

Lift offStroke 2Stroke 6Stroke 10Stroke 14Stroke 18

0.06

0.04

0.02

R


0

0 50 100 150

coordinate (deg.)

200 250 300 350

0.02

0.04

500.06

Stroke 18Stroke 19

0.06

0.04

0.02

R


0

0 50 100 150

coordinate (deg.)

200 250

Stroke 39Stroke 35Stroke 31Stroke 27Stroke 23Stroke 19

300 350

0.02

0.04

500.06

Figure 21. Evolution of the planimetry of the inner ring. From lift off to stroke no. 18 (left), situation after the correction stroke

(center) and from stroke no. 19 to stroke no. 39 (right)

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(no. 39) was determined to be 138 mm. Table 6 shows

the pin distance measures and the final distances after

the last stroke.All distances are lower than 10 374 mm.

Nevertheless, final distances of control radii nos. 3 and

7, are respectively 8 mm and 5 mm shorter than the

minimum 10 273 mm. This inconvenience was not

relevant because the flexibility of the long plate

members allowed their installation into a slightly shorter

distance. The different distances (ranging 95 mm)

were compensated after the transfer by the flexibility

of the lower chord of the inner ring.

Transfer and completion

At stroke no. 39 the structure reached the top positionprior to transfer with an average upward travel equal to

17,039 m. Then the inner bracing ring bars were

added, and the permanent radial tension members

were installed as explained in section 4. Jack forces

were released individually (Fig 22) and the permanent

members gradually reached the necessary tensioned

state. After this operation the inner ring accommodated

to a final average travel equal to 16,873 m, with

differences within a range of 25 mm, which was

considered fully satisfactory considering that the target

upward travel was 16,868 m (refer to Section 3). Thesurvey before and after the transfer (Fig 23) shows the

flattening of the inner ring geometry, with total

differences ofz smaller than 0,035 m (1/3750 of the

inner ring perimeter). The effect of the transfer in the

planimetry is opposite: a planimetric increased



Figure 22. Force transfer to the tension members. Note the position of the jack (2nd from left) prior and after releasing the tension

0.08

0.06

0.04

0.02

Difference

be

tweenzan

daveragez

(m)

0

0 50 100 150

coordinate (deg.)

200 250 300 350

Stroke 39Situation after transfer

0.02

0.04

500.06

0.06

0.04

0.02

R

referre

dtotheorig

ina

lgeome

try

(m)

0

0 50 100 150

coordinate (deg.)

200 250

Stroke 39Situation after transfer

300 350

0.02

0.04

500.06

Figure 23. Geometry before and after the transfer. Upward travel increments (left) and changes in the radius (right)

Table 6. Control distances for the transfer process

Control radius Distancebefore Final distance

no. last stroke (mm) (mm)

1 10 485 10 347

2 10 451 10 3133 10 403 10 265

4 10 439 10 301

5 10 498 10 360

6 10 457 10 319

7 10 406 10 268

8 10 496 10 358

Average / Target 10 454 10 316

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distortion was measured, with maximum final

differences lower than 0,09 m (1/1450 of the inner ring

perimeter). Both values were judged as acceptable.

Thereafter the remaining radial members and bracing

members were added to complete the final structural

system. A special feature of this Pantadome system

is that it is unnecessary to add the remainingstructural members prior to the transfer because the

system is self-stable for a fixed length of the tension

members. With the addition of a folded plate, thermal

insulation, and tin-coated waterproofing the roof was

finished.

6. CONCLUSIONThe construction and detailing of a roof structure,

erected by means of an innovative variant of the

Pantadome system conceived by Prof. M. Kawaguchi,

has been described. The roof is spherical dome-shaped, has an inner opening of 42 m in diameter and

an exterior diameter of 101,6 m. It is supported on 44

columns located on a circumference of diameter 86,4 m.

The structural system is formed by radial truss lattices

pinned to the columns and to the inner ring and

supported by the action of an outer tension ring, radial

tension members and tension (upper chord) and

compression (lower chord) in the inner ring.

Lifting of the 4 530 kN heavy Pantadome was

achieved by pulling and shortening 44 groups of four

provisory strands, by means of jacks attached to thelower chord of the inner ring. Once the target

geometry was achieved, radial forces were transferred

to permanent tension members. In contrast to previous

Pantadomes, no vertical jacks were needed for the

lifting. The deployable system is self-stable because

the pulling devices constitute a part of it; therefore it

was not necessary to complete the structure with the

remaining members prior to the force transfer.

Hinges and special pieces for fixing the strands and

jacks needed to be carefully studied and especially

designed once the pulling system was decided. The

force transfer could be easily executed using short rod

pieces which permitted the necessary tolerances to

install the permanent tension members. Geometrical

survey at several steps of the lifting played an important

role to control that the overall deformation of the

structure was kept into allowable values. The overall

duration of the deployment was mainly conditioned bythe time needed for the survey after every two or four

strokes. The new erection system allowed the

construction of the dome in a quick and safe way.

ACKNOWLEDGEMENTSXtivas bullring roof has been financed by the

municipality of the town and the Valencian Regional

Government. Authors are grateful to the major Mr.

Alfonso Rus for the daring decision of allowing the

unprecedented Pantadome lifting. The realization was

achieved thanks to the engineering work of the staffsofKawaguchi & Engineers and CMD Ingenieros. The

contributions of Eng. Francisco Palacios (CMD), Dr.

Minoru Matsui (K&E), Eng. Javier Martnez of VSL

Heavy Lifting and Mr. Jos L. Jimnez ofLlanera

Construccin deserve special acknowledgement.

REFERENCES[1] Lzaro C., Domingo A., Kawaguchi M., et al.,

Renovation of the bullring arena of Xtiva (Spain), in

Majowiecky M. (ed.), Structural Architecture:

Proceedings of the IASS Symposium 2007, Venice, 2007.

[2] Kawaguchi M., Space structures with changing

geometries, Bulletin of the IASS, vol. 31 (1-2), no.

102103, 1990, pp. 3345.

[3] Kawaguchi M., Abe M., Design and construction of Sant

Jordi Sports Palace, Bulletin of the IASS, Vol. 33(2),

no. 109, 1992, pp. 6988

[4] Chilton J., Space Grid Structures, Architectural Press,

2000

[5] Une H., Shimizu H., Matsui E., Kawaguchi M., Abe M.,

Design and realization of a large-scale coal storage

facility. Part 2 The analysis of the structure during the

pushing up work. Proceedings of the IASS Symposium

2001 (Theory, Design and Realization of Shell and

Spatial Structures), H. Kuneida (ed.), Nagoya, 2001

pentadome

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