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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
adoming@cst.upv.es
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: carlafer@mes.upv.es
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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
International Journal of Space Structures Vol. 25 No. 4 2010 231
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
232 International Journal of Space Structures Vol. 25 No. 4 2010
Detailing and Construction of the PantadomeRoof Structure for a Bullring in Xtiva (Spain)
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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Carlos Lzaro, Alberto Domingo
International Journal of Space Structures Vol. 25 No. 4 2010 233
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.
234 International Journal of Space Structures Vol. 25 No. 4 2010
Detailing and Construction of the PantadomeRoof Structure for a Bullring in Xtiva (Spain)
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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International Journal of Space Structures Vol. 25 No. 4 2010 235
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
236 International Journal of Space Structures Vol. 25 No. 4 2010
Detailing and Construction of the PantadomeRoof Structure for a Bullring in Xtiva (Spain)
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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International Journal of Space Structures Vol. 25 No. 4 2010 237
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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Detailing and Construction of the PantadomeRoof Structure for a Bullring in Xtiva (Spain)
238 International Journal of Space Structures Vol. 25 No. 4 2010
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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Carlos Lzaro, Alberto Domingo
International Journal of Space Structures Vol. 25 No. 4 2010 239
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
Differencebetweenzandaveragez(m)
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
Differencebetweenzandaveragez(m)
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
referredtotheoriginalgeometry(m)
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
referredtotheoriginalgeometry(m)
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
240 International Journal of Space Structures Vol. 25 No. 4 2010
Detailing and Construction of the PantadomeRoof Structure for a Bullring in Xtiva (Spain)
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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Carlos Lzaro, Alberto Domingo
International Journal of Space Structures Vol. 25 No. 4 2010 241
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
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