BRITISH PAVILION, 1988-1992

Seville, Spain

Nicholas Grimshaw and Partners

The theme for Expo 92 in Seville was “The Age of Discovery,” a remembrance of the 500th anniversary of Christopher Columbus’ voyage to the Americas and a time in history when Seville was the center of trade for the Spanish foothold in the New World.

To mark British participation in the event, Nicholas Grimshaw and Partners created a modern Crystal Palace. Reinterpreting indigenous building response to the hot dry summers of Seville, the UK Pavilion combines High Tech vocabulary with solar technology to produce a show­piece of British know-how.

TABLE 8.9 Fact Sheet
Project	Building Name Client City Lat/Long/Elev	British Pavilion, Expo 92 U. K. Department of Trade and Industry Seville, Andalucia, Spain 37.4 N 6.0 W, 30 ft (9 m)
Team	Architect Engineer Quantity Surveyors Exhibition Design Water Wall Contracting	Nicholas Grimshaw and Partners Ove Arup & Partners (structure and mechanical) Davis Langdon & Everest RSCG Conran Design Ltd. William Pye Partnership Trafalgar House Construction Management Ltd.
General	Time Line Floor Area Occupants Cost 1995 cost in $US Stories	Competition invitations: December 1988. Construction September 1990 to April 1992, with substantial completion December 1991 to allow for commissioning and exhibit installations. 63,480 ft2 (5,897.5 m2) in a 22,320 ft2 (2,073.6 m2) footprint. Up to 20,000 visitors per day. $ 35.4 million (£20.0 million), or $557/ft2. About 70% of the budget is in the building shell and core, with the other 30% for interior fittings. This does not include the cost of the exhibits. $ 39.6 million, or about $623/ft2 Four levels in a single volume reaching to 59 ft (18 m) at the top of the glass wall and 81.4 ft (24.8 m) to the roof.
Site	Site Description Parking, Cars	95 pavilions on an island in the Guadalquivir River, with a 1.5 acre (6,200 m2) site for the U. K. Pavilion. Shared parking for fairgrounds located to west of building.
Structure	Foundation Vertical Members Horizontal Spans	Concrete piers and slab on grade. Ten 71.2 ft (21.7 m) tall wall frames provided ten column points on east and west wall. Ten 105 ft (32 m) inverted bow roof trusses
Envelope	Glass and Glazing Skylights Cladding Roof	Walls are 8.2 ft x 5.9 ft (2.5 m x 1.8 m), east wall is clear at the first 16.4 ft (5 m) and fritted glass at the top 42.7 ft (13 m). None. Glass to east, fabric sails on north and south, and water wall to west. PVC membrane over insulation on metal deck. Photovoltaic array on fabric shades.
HVAC	Equipment Cooling Type Distribution Duct Type Vertical Chases	Two chillers located in ground floor service area beneath the concourse. Direct expansion with river water heat rejection rather than cooling towers. Raised floor plenums under exhibit, office, and auditorium floors. Elliptical metal ducts. None.
Interior	Partitions Finishes Vertical Circulation Furniture Lighting	Enclosed auditorium pods. Glass handrails and exposed structure. Inclined moving walkway travelators and two elevators. Exhibit design for display. Metal halide floods, recessed downlighting, concealed strip lights in walkways and handrails.

Photovoltaic array on fabric shades.

PVC membrane over insulation on metal deck.

Glass wall panes are 2.5m x 1,8m, east wall is clear at the first 5m and fritted glass at the top 13m. Glass to east, fabric sails on north and south, and water wall to west.

Interior metal halide floodlights, recessed downlighting, concealed strip lights in walkways and handrails.

Cascading water wall provides indirect evaporative cooling of building and relieves temperatures around the building.

Ten 32 m inverted bow roof trusses on ten 21.7m tall wall frames on east and west wall.

Two direct expansion chillers located in ground-floor service area beneath the concourse. River water used for heat rejection rather than cooling towers.

Program

Client

The British government’s Department of Trade and Industry (DTI) states its mission thus: “To increase com­petitiveness and scientific excellence in order to generate higher levels of sustainable growth and productivity in a modern economy.” DTI promotes commerce at home and abroad through regulatory policy and direct support of British interests.

In keeping with its mission, DTI had several goals in mind for participation in Expo 92. Most of these were ambassadorial, such as promoting the image of British enterprise and technical excellence. The agency could rationalize the expense of such a grand gesture only by the stimulus it would provide for the U. K. economy. Along these same lines, the building design had to promote a high level of private commercial participation and finan­cial contribution to the pavilion. A survey performed to poll Spanish perceptions of British culture revealed an image of stogy conservatism. DTI had something much different in mind and set out to build a progressive and forward-looking icon that would represent an advanced industrial nation.

Brief

Operationally, the client’s brief established three categories of design objectives. Programmatically, the pavilion would serve national interests with a strong image easily identi­fied with the United Kingdom. Functional goals were described by their themes without distinct area require­ments:

• Unobstructed floor space for exhibition design

• Concession areas for fine dining

• Retail areas

• Circulation for 20,000 visitors per day for the six month duration of the Expo, from April through October 1992

• Access for disabled persons

• Staff offices

• Separate VIP entry, reception, and dining facilities

• A third category of requirements proposed that the pavilion be dismantled after the Expo and reassem­bled on a site to be determined later

Site

Expo 92 was sited on reclaimed land along the Guadalquivir River, a name bequeathed by the Arabic rulers of the eighth century as Wadi al-Kabir, meaning “Great River.” The island site, La Cartuja, is on the north side of Seville about 50 miles (80 km) from the Mediterranean coast. It is reportedly the spot from which Christopher Columbus sailed to the New World. From Roman times to the Middle Ages and Moorish occupation, the river was navigable from the Atlantic Ocean inland past Seville and as far as Cordoba. The Muslim city of Granada fell just ten months before Columbus sailed, ending nearly eight centuries of Muslim rule in Iberia. In recent history silt accumulation has made the river impassable to com­mercial navigation upstream north of Seville.

Seville is the administrative capital and largest city in the autonomous state of Andalucia. Central Seville had a 1985 population of about 800,000, with some 1.5 million residents in the 5400 mi2 (14,000 km2) region. Andalucia had a 1990 population of 7,100,060. Expo 92 was held there partly in hopes of invigorating its chronically under­developed economy. Agriculture is the primary industry, but Andalusian farm laborers are among the poorest in Europe and many had migrated to the industrial centers of Madrid and Catalonia, seeking new employment. Seville, embellished by Moorish architecture and once celebrated as a center of culture, art, and science, saw tourism and the related service industry as a new means of vitality. Expo 92 was envisioned as a way of promoting its attractions. Perhaps now, 500 years after Seville set forth to discover the New World, the world would rediscover Seville.

Expo 92 Time Line

• May 1976 — King Juan Carlos of Spain announces the intention to host Expo 92, vowing to promote the qualities of Spain and the Latin-American nations.

• March 1982 — Seville applies to the Bureau International des Expositions (BIE), requesting to host a world exposition commemorating the fifth centennial of Columbus’s first voyage.

• June 1982—The Isle de la Cartuja is announced as the exposition site.

• June 1983—The Internal Bureau of Exhibitions in Paris approves the general provisions of the fair.

• November 1984—Manuel Olivencia Ruiz is appoint­ed commissioner general of the exposition.

• April 1985—The Spanish government launches the organizational structure of the exposition. Sociedad Estatal para la Exposicion Universal Seville 92 SA is founded. The exposition budget is placed at 183.7 million pesetas.

• February 15, 1986 — The Spanish Council of Ministers approves the general plan for the exposition.

Architect Ricardo Bofill was an early candidate for commissioner general of the Expo, but Manuel Olivencia
was eventually chosen. Infrastructure projects to support the event were put in motion, including five new bridges to Isle de la Cartuja. Notably, one of two bridges designed by Santiago Calatrava was erected: the 656 ft (200 m) span, El Alamillo, with its 466 ft (142 m) mast at the northern end of the island. Seville’s San Pablo Airport was completely renovated for the fair by Rafeael Moneo (1987-1991), and a new city ring road constructed to keep things moving. A high-speed railway was built to connect Seville with Madrid, joining the new Santa Justa Station rail terminal, by Seville architects Cruz and Ortiz, with their mentor Moneo’s Atocha Station in Madrid. These and other works—some public infrastructure and some for tourism industries—would benefit Seville and Andalucia long after Expo 92 was converted to other uses.

Figure 8.32 Annual hours of temperature occurrence for daytime and night hours in Seville.

Cartuja Island was a 538 acre (215 hectare) strip of desolate and unused territory harboring the old Carthusain monastery of La Caruja de las Cuevas. It lay just across the river from Old Quarter Seville. The monastery, where Christopher Columbus stayed before his journey and was buried briefly, was conserved on the southern end of the island. The northern two-thirds of the site were gridded for 70 major pavilions. To the east side of the pavilion blocks, an entertainment zone was erected around a 40 acre (16 ha) artificial Lake of Spain. Parking was placed along the western waterfront of the island. Canals were dug to separate the lake from the pavilion zone. For site circulation and elevated viewing of the fair there was a monorail system circling the site, and a 6.6 mi (11 km) cable car system ran above the central fairground avenue and into the old town. Barqueta Bridge spans into the entertainment zone, and Calatrava’s Cartuja Bridge crosses at the Monastery.

Climate

Seville is hot and dry. It has, in fact, arguably the hottest cli­mate in Europe. Daytime temperatures can reach 115°F (46°C), with lows of 40°F (5°C) the same night. The aver­age daily temperature range between daily high and daily low in July is 29°F (16°C). Dryness promotes these large daily swings. Low relative humidity levels allow both mas­sive solar heat gains during the blue-sky day and corre­spondingly high radiant flux back to the clear night sky. The large daily temperature range negates the usefulness of degree-days—there are statistically only 980 degree-days cooling and 1780 degree-days heating annually, because degree-day calculations are based on average daily temper­ature and tend to cancel out warm days with cool nights. Hourly bin data more accurately shows that there are 1363 hours per typical year when temperatures exceed 80°F. In comparison, Albuquerque, New Mexico, experiences only 1063 such hours. Seville’s hot temperatures account for

		Jan.	Feb.	Mar.	Apr.	May	June	July	Aug.	Sept.	Oct.	Nov.	Dec.	Year
	Degree-Days Heating	417	308	221	143	41	2	0	0	0	30	188	358	1712
Temperature	Degree-Days Cooling	0	0	4	17	98	292	497	505	370	115	8	0	1915
Extreme High	75	79	88	93	102	111	111	113	111	97	88	75	113
Normal High	61	63	69	71	79	87	95	95	90	78	69	62	77
Normal Average	52	54	58	61	67	75	81	81	77	67	59	53	66
Normal Low	42	44	46	50	55	62	66	67	64	56	49	44	54
	Extreme Low	25	27	32	34	43	46	57	55	48	39	30	23	23
	Dew Point	43	44	45	48	51	56	59	59	58	53	49	45	51
Humidity	Max % RH	87	87	84	86	85	83	77	77	80	83	87	87	84
Min % RH	59	57	47	48	42	37	31	32	35	46	56	61	46
% Days with Rain	30	30	23	36	23	13	3	7	10	26	26	36	22
	Rain Inches	3	2	4	2	2	0	0	0	1	3	3	3	23
Sky	% Overcast Days	15	17	10	14	8	5	1	2	3	9	13	17	10
% Clear Days	37	31	37	24	29	42	67	67	50	36	36	35	41
Wind	Prevailing Direction	NE	NE	NE	SW	SW	SW	SW	SW	SW	NE	NE	NE	SW
Speed, Knots	7	7	7	9	9	9	9	9	8	7	7	7	8
Percent Calm	35	30	29	26	23	23	24	26	30	32	32	30	28
	Rain	9	9	7	11	7	4	1	2	3	8	8	11	80
Days Observed	Fog	12	10	9	9	10	9	6	6	8	7	8	11	105
Haze	8	9	9	9	11	13	12	11	11	7	7	9	116
Snow	0	0	0	0	0	0	0	0	0	0	0	0	0
Hail	0	0	#	0	#	0	0	0	0	0	#	#	#
Freezing Rain	0	0	0	0	0	0	0	0	0	0	0	0	0
	Blowing Sand	6	5	4	4	4	6	4	4	4	3	3	3	50

table 8.10 Normal Climate Data for Seville, Spain

15.6 percent of all annual weather. The same analysis lim­ited to daytime hours of 6:00 to 18:00 is more telling: 25 percent of all daylight hours are over 80°F, 11 percent over 90°F, and 2 percent over 100°F annually. Further isolating the climate to a typical July day, the same analysis reveals that 100 percent of all daylight hours are over 80°F, 68 per­cent over 90°F, and 20 percent over 100°F. Coincidently, Expo 92 was held during Seville’s dry weather period, when
all of these hot hours occur: April to October. At least it was cool as soon as the sun went down; 30 percent of all July hours from 18:00 to 6:00 are below 70°F.

Passive and indigenous building response to this cli­mate emphasizes the usual hot-arid solutions: high enve­lope and internal mass construction with small well-shaded openings and lots of moisture for evaporative cooling. At the Expo, misting towers were distributed around the fairgrounds to provide atomized jets of cooling humidity in the open air

Intention

Design Team

Nicholas Grimshaw and Partners, NGP, is a London firm founded in 1967; today this office is about the same size as

Richard Rogers & Partners. Though slightly younger than Rogers and Norman Foster, Grimshaw is usually associated with the same High Tech movement and pursuit of techni­cal rigor. A remarkable aspect of his office is youth; the aver­age age of the staff and directors, including Grimshaw, is presently about 32. Four members of his 1988 office who have remained are currently directors: David Harriss, Chris Nash, Andrew Whalley, and Neven Sidor.

The 1992 British Pavilion marks NGP’s return to Modernism, a coup that was followed by the equally remarkable 1993 Waterloo International Terminal in London. Since that time NGP has continually expanded the scope of its work in every way—project volume, building type and size, design context, and geographical location around the world. It is also one of the few firms to operate a semi-independent product design firm with whom it collaborates on most NGP building projects.

philosophy

Our work is concerned with producing buildings and products which are noticeably more joyful, interesting and understandable than the norm through intelligent process.

Chris Nash, NGP Director

Nicholas Grimshaw studied architecture at the Edinburg College of Art and at the Architectural Association. As a young graduate he fell under the influ­ence of the avant-garde Archigram, its technophilia, and its countercultural mission to destroy Modernism as a sty­listic pursuit and restore its sociotechnic ideals. Archigram is still remembered for a series of underground-style pub­lications and surreal futuristic proposals for rebuilding the world—Instant City, Plug-In City, even Walking City— but none of its members’ designs were ever built. Grimshaw felt an affinity for Archigram’s ideas, but he wanted to build and his passion for building well led to the founding of his own practice.

Crafted detail and technical rigor are keynotes of NGP architecture. The firm also subscribes to another of the Archigram visions—the merging of information systems and buildings. In 1988 it converted to design-by-comput – er in a single reorganization of the office, without trying to phase it in gradually. Working with its product division, the firm uses the computer media as a design tool that closes the gap between design and making, as well as between the extravagance of custom components and the precision of industrial fabrication.

Dry-Bulb Temperature, °F Figure 8.34 Bin data distribution for Seville. Concentric areas of graph indicate the number of hours per year that weather conditions normally occur in this climate. Similar to elevation readings on topographic maps, highest frequency occurrences of weather are at the center peaks of the graph. (Data sources: Engineering Weather Data, typical meteorological year (TMY) data from the National Climatic Data Center, and the ASHRAE Weather Data Viewer from the American Society of Heating, Refrigerating and Air-Conditioning Engineers.)

Intent

On one hand, Grimshaw and his team brought a devotion to technically expressed systems to the project as a means of evoking Britain’s industrial and scientific prowess. On the other hand, the design would have to deal with the uncompromisingly hot-arid climate in elegant style. Oppositions between these two ideals, the use of High Tech kit of parts versus climate-responsive building tech­niques, stimulated the directions this pavilion would take. Rather than taking the typical Modernist universal machine approach, Grimshaw and his team would fine – tune the universally adaptable kit of industrial parts to serve the particular environmental criteria of a specific place.

Critical Technical Issues

Inherent

World’s fairs are always challenging from the perspective of time, construction, and economics. Anticipating these con­straints, DTI committed to Expo 92 early and was reward­ed with the choice of a prime building site from the many parcels still available. An early start was something of a dis­advantage later, however, because the British construction team was always the first to encounter minor coordination problems with site regulations or Seville building officials. Other participants came to rely on the DTI’s experiences to smooth the way for their own projects.

Everyone attending Expo 92 would have high expecta­tions of the pavilions they came to see. The final building product would have to be impressive enough to commu­nicate its British message. Architectural innovation and expression had key roles in achieving this objective and would play to the theme, “The Age of Discovery"

Climate would also play a role. Seville is mostly hot and sunny April through October, with 100°F tempera­tures possible any day and certain on many. With crowds of up to 20,000 visitors to the pavilion per day, satisfying the need for an indoor oasis would attract attention and appreciation.

Contextual

It was decided early on to prefabricate the building in the United Kingdom and ship it to Seville for on-site assem­bly. This was seen as the most reliable way to control qual­ity and meet the construction schedule. Transportation strategies dictated that nothing shipped to the site could exceed 82 ft (25 m) in length or weigh more than 8.4 tons (7.5 tonnes).

Spanish building codes were also something of an issue. First, the earthquake resistance standards for the Seville area were relatively strict. Second, the problems of language and building conventions would have to be over­come.

Intentional

The brief’s requirement for technical wizardry fit well with the architects’ philosophy of elevating finely refined technical solutions to the status of pure architecture.

The minimalist aesthetic of glass and steel building vocabulary was challenged by a climate that was best tem­pered with deep shade, thick massive construction, and open surfaces of water.

Appropriate Systems

Grimshaw’s general solution to the program placed the building under a shading array of photovoltaic collectors and surrounded it with pools of water. The envelope employs different passive cooling strategies on each sur­face and houses a single grand volume where most activi­ties are placed on an elevated concourse. Partial floors are
suspended above the concourse for exhibit space and reached by inclined moving walkways rather than stairs. Service and office functions are buried below the con­course. Heat is allowed to stratify and exhaust at roof level, so the pavilion environment is buffered but not mechani­cally controlled. Air-conditioned cooling is reserved pri­marily for auditorium spaces contained in upper-level pods. The structural frame is expressed to the exterior as part of an extended envelope system that mediates between inside and out. On the interior the frame becomes an armature for the circulation system and plat­form floors that lead to the auditoriums.

Precedent

The progression from Paxton’s Crystal Palace, to Dutert’s Gallery of Machines, and on through the history of pavil­ion architecture remains an inspiration, especially to Modernist architects who favor the industrial systems mode of construction and its premises in design. Nicholas Grimshaw, for one, is not shy about direct references to the Crystal Palace.

Site

A 1.5 acre (6200 m2) building plot was selected, fronting on the fair’s principal International Avenue and adjacent to the west gate entry from the parking areas. Its long sides face west-northwest (WNW) to a row of service buildings and ESE to International Avenue. Views east from the pavilion entry facade look down European Avenue to the lake, where the Spanish Pavilion was sited on the water’s edge.

Direct solar radiation would have greatest impact on the roof, the south and west sides of the building (SSW and WNW). The entry side to the ESE would only receive a few hours of direct sun per day. On July 21, for example, the long entry elevation is illuminated by sunlight at a 25- degree profile angle at 7:00 a. m. and receives some direct sun until 11:00 a. m. when the profile angle is 70 degrees. This exposure happens during cooler hours of the day, however, and some potential shading of low sun may be provided by surrounding pavilions. The July sun actually rises and sets 25 degrees north of the east-west horizon points at this latitude. Because the building is shifted clockwise in plan about 15 degrees east from true north, the east wall is spared some sun and the west wall expo­sure is exaggerated. The sun faces squarely on the entry wall at 9:00 a. m. solar time, when the July sun is already 60 degrees above the horizon. Meanwhile, the back wall west orientation is sunlit during the hot July afternoon from 1:00 p. m. to 7:00 p. m. without much shading from sur­rounding structures. Profile angles are quite low on the west side after 4:00 p. m., and the incidence angle to the window approaches normal right at 5:30 p. m.

Structure

This site is about 30 ft (9 m) above the Guadalquivir’s nor­mal flow and was previously used as farmland. Soils con­sist of soft alluvial silts deposited by the river and a lower level of dense gravel down to 60 ft (18 m). A grid of driv­en piles was placed to support the column loads of the building, followed by pile caps and a concrete slab that was poured slightly below existing grade. A basement level was constructed for services and office space.

Superstructure work began with framework for the interior, essentially an autonomous support system for suspended partial floor levels and moving walkways lead­ing up to the enclosed auditorium pods. Four pairs of col­umn feet supported each of three structural trees rising from the basement to the base of the auditoriums. The

65.6 ft (20 m) distance between columns was spanned by thick wall pipe Warren trusses that supported floors of poured concrete over profiled deck. The Warren trusses tapered toward both ends of the span and were supported at both ends between the paired columns. Cross bracing from north to south at the center bay of the interior frame provided lateral stability.

This interior frame penetrated the exterior super­structure and envelope systems to join outside open fire stairs on the north, south, and west elevations. For later­al support the interior frame was shifted off center to the west wall. This spacing provided more open area on the east entry side and simplified bracing of the two frames together above the pods at the west wall. Moving walk­way “travelators” crisscrossed the platforms on the east and west edges of the interior frame. These were hung from the interior frame by attachment to the pod col­umn feet and supported on prismatic pipe trusses. Each of these had two top chords and two more chords paired at the narrow base. The profile of the walkway trusses was formed by passing the chords through steel cross plates.

After the interior structure was in place, work started on the exterior frame. The exterior superstructure consist­ed of 12.9 in. (327 mm) tubular steel wall frames 4.9 ft (1.5 m) deep and 71.2 ft (21.7 m) tall. Five of these were placed along the east wall and five along the west. Each of these frameworks formed two vertical trusses, making a support grid of 10 columns across each long side of the building at

23.6 ft (7.2 m) centers. They were shipped full height and erected in one day. Next, ten 105 ft (32 m) inverted bow trusses for the roof were shipped in two parts and con­nected during erection at their midspan with pin joints. These roof trusses overhang the wall columns and are connected to them by more pin joints. Lateral stability of the frame was achieved by cross bracing the center bay along both sides and the roof. This one stiff bay was
attached to all the other bays by slender horizontal tubes and roof purlins.

North and south walls are framed by mast-shaped trusses with pin connections at their base and a roller bearing connection at the roof that prevented the transfer of vertical loads. Each truss has three vertical members. A curved 12.8 in. (324 mm) diameter pipe forms the center and main structural element. Tapered spreaders project spinelike from the center pipe to hold off the other two vertical members, which are stainless steel rigging rods. These inside and outside riggings hold the truss in tension against wind loads.

Envelope

The six-month duration of Expo 92 extending through the dry summer season meant that the British Pavilion’s enve­lope would have a single purpose, cooling. This logic motivated the dramatic use of different strategies on each of the exterior envelope surfaces as well as in their carry­over expression into the site and interior systems. Because of the extension of its parts into other systems, even the articulated frame of the structure appears to be an active participant in this environmental servicing.

The east wall is a waterfall that cascades from roof eave level down across an entry canopy. The entry is itself ele­vated up a sloping ramp and suspended as a bridge across a lake fronting the entry and the east side of the building. The entry canopy diverts the cascading waterfall from the covered doorway but surrounds approaching visitors with streams of water from nozzles at its side edges. The wall actually consists of 0.5 in. (12.5 mm) gray-tinted glass panels hung from rectangular steel sections at the top of the wall. The upper 41.0 ft (12.5 m) of glass is patterned to enhance the translucent effect of the waterfall. At the 16.4 ft (5 m) level, a thin gutter converts the waterfall film to thin streams that splash into the lake at the base of the wall. The glass below the gutter is clear and untinted to give an inviting view into the interior and is recessed a few inches away from the waterfall.

A high mass wall was instantly created to the long west-facing orientation by an interlocking stack of 24 water-filled metal freight containers that were piled to a height of 49.2 ft (15 m). Each container was 23.6 ft long X 3.3 ft wide X 8.2 ft deep (7.2- X 1.0 m X 2.5 m), lined with a waterproof membrane, internally insulated on the interior wall side, and painted white to reflect unwanted solar heat gain. This wall acted as a giant thermal flywheel, warming by day and cooling by night but effectively remaining at about average daily air temperature. The containers held 18,300 ft3 (518 m3) of water, constituting a thermal mass of some 1.2 million Btu/°F. At the average daily July dry-bulb temperature, this wall would remain at about 81°F all day, the same temperature as human skin. According to the engineers at Arup & Partners, the inside surface stayed constant at 86°F (30°C) while the exposed face experienced a 77°F (25°C) temperature swing between day and night extremes. As a bonus, seven of these tanks were used as part of the potable water supply system.

Closure of both the east and west walls is made out­side the truss column structure. At the top of the wall, however, eaves between the ten roof trusses had polycar­bonate ventilation louvers set back to the plane of the inside structural member. Insulated glass-reinforced plas­tic (GRP) glazing panels on the top diagonal chord of the wall truss connected the eave to the wall.

The narrow 105.0 ft wide X 82.0 ft high (32 m X 25 m) north and south walls are translucent fabric screens. Panels 13.2 ft (4 m) wide of a PVC-coated polyester sail fabric were stretched over the structural center steel pipe member of the masts outside both end walls. There is no glass. On the south side, an additional layer of pennants was attached to the frames to block sunlight, but these were not needed on the shady north elevation. A 0.75 in. (20 mm) glass panel closes both of these walls at their base.

On the roof, a PVC membrane over rigid insulation on a steel deck provided the weather closure. Above that, an array of photovoltaic solar panels was installed over south-facing fabric sunshades stretched across an S – shaped metal frame. The shades were held above the roof to allow cooling breezes to wash the roof surface. There is no storm drain system on the roof. The infrequent sum­mer rains were to be allowed to evaporate in place, pro­viding some extra cooling relief to the interior. It happened that 1992 was an unusual summer, with some heavy rainfall and unusually low temperatures during the Expo. Even in these extreme conditions, runoff from the roof was usually contained and any discharge over the eaves quickly evaporated on the envelope.

Electricity from the photovoltaics was used to pump water across the east wall via 26 submersible pumps. Four larger pumps driven by on-line power were used for back­up and nighttime duty.

Mechanical

Night flush cooling was incorporated into the mechanical design with four air-handling units (AHUs) totaling 46,615 ft3/min (22 m3/sec) drawing air through the eaves and ducting it below the pods across the pavilion about 30 ft (9 m) above the concourse. By day, air was allowed to stratify in the space and be exhausted through the east or west eave louvers. Sensors monitored wind direction and opened the leeward side louvers accordingly. This tended to keep cool­er air at the lower concourse levels circulating upward after it had been cooled evaporatively by the water features.

Offices and restaurants at the lower ground level had separate AHUs distributing mechanically cooled air through pressurized floor plenums. The auditorium pods and theVIP suite had individual units that drew air from the upper levels, cooled and delivered it to occupants, then returned it to the pavilion space still cooler than before its use. Limiting the mechanically cooled areas to spaces with high occupancy density helped keep the total building ener­gy use an estimated 33 percent lower than a fully condi­tioned version of the pavilion would have consumed. In addition, water was conserved by the elimination of cooling towers and evaporative condensers. Instead, a community­sized system took river water from upstream and distrib­uted it to each Expo pavilion for heat rejection before discharging it back into the Guadalquivir downstream.

Daylighting through the translucent east waterwall and the sail-fabric north and south walls provided most of the required illumination by day. There was, in fact, some conflict with the desirable low level of background light in the exhibits where accent lighting and computer screens were muted by the abundant natural light. At night, how­ever, several artificial lighting systems produced a more controlled and dramatic effect. Floodlighting with 150 W cold white metal halide fixtures was used to highlight the wall trusses. Underwater 300 W spotlights washed the lower 16.4 ft (5 m) of the waterwall. Downlights in the floor decks held ambient illumination to about 4 fc (40 lux). Spotlights at the top and bottom of the end walls made the sails glow. The fabric roof shades were uplit with floodlights. At the pedestrian scale, travelators were lit with fluorescent strip lights in the side skirting and handrails.

Interior

An entry ramp elevated 8.2 ft (2.5 m) above the site runs through the east waterwall as a bridge at the northeast cor­ner of the pavilion. This brings visitors over a 210.0 ft X

52.5 ft (64 m X 16 m) pond that runs across the entire east side of the building and extends about 26 ft (8 m) away from the east wall as well as 26 ft (8 m) inside the build­ing. The bridge finally lands at the 14,746 ft2 (1370 m2) concourse level 8.2 ft (2.5 m) above the pond and 13.8 ft (4.2 m) above an open courtyard and cafe that are depressed 5.6 ft (1.7 m) below grade on the 26,370 ft2 (2450 m2) floor slab. Offices and service areas are buried beneath the concourse itself. Two elevators are located against the north wall, but most circulation through the pavilion is by long moving walkways slowly inclined from platform to platform across the open volume above the concourse. The +8.2 ft concourse level contains the spon­sors’ exhibits, a shop, and the information desk. The main exit ramp leaves through the south wall from the other end of the concourse.

At the next level, +24.6 ft (7.5 m), platform floors are used for an additional 6,243 ft2 (580 m2) of exhibit space. Connecting walkways between the platforms at every level extend to the exterior fire stairs. Above is the 11,840 ft2 (1100 m2) pod level, at 41.0 ft (12.5 m), with the two enclosed auditoriums and a central deck between them. The highest level, +57.4 ft (17.5 m), contains the 3,875 ft2 (360 m2) VIP suite.

Integration Highlights

Physical

• Prefabrication ensured accurate field fit of all compo­nents and allowed a small construction crew to erect the building rapidly.

Visual

• High Tech expressiveness was used to convey the DTI- mandated image of an innovative business culture.

• Spitting the pod columns into pairs reduced their visual bulk.

Performance

• Climatic challenges posed by the Seville heat were transformed into architectural features: the waterwall, pools and fountains, shading sails, and photovoltaic panel roof shades are relevant examples.

• Prefabrication of a kit of parts for the building facili­tated its reuse after the Expo. Following disassembly, the solar panels, submersible pumps, and water stor­age containers could be recycled into infrastructure systems for sites in developing countries. Alternately, the building could be reassembled at a site to be determined. Ideally, though, the building would remain in Seville and be converted, altered, or expanded for a different use.

• The waterfall on the east wall was evaporatively cooled to about 75°F (24°C), leaving it cooler than body temperature and providing a source of radiant relief to occupants.

• The pin-connected structural system provided ductil­ity of frame to meet seismic codes. It also allowed for rapid on-site assembly by small crews.

Discussion

In the end, Seville was a popular success. More than 42 million people passed through its gates to see the 95 major pavilions and the expositions representing 110 participat­ing organizations and nations. Thirty percent of the expo­sition buildings on Cartuja, or about 1.3 million ft2 (125,000 m2) were to remain standing after the event closed. The American Pavilion, for example, is now part of the local university.