GSAPP ATII Structures 2021 - Group 3 final project

Portuguese Pavilion Submitted by Daniel Chang, Rebecca Faris, Ji Yoon (Kelly) Lee, Nicolas Nefiodow, and Cemre Tokat in partial fulfilment of the GSAPP M. Arch. technology sequence.

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CONTENTS 03

Background Information

04

Elemental Form

05

Related Projects by Álvaro Siza Viera

06

Novel Design Constraints

09

Material Selection

10

Construction Overview

12

Pouring of Concrete

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Internal Forces

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Computational Anal ysis

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Physical Model

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Contact Info

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Sources

Background Information Client: Parque Expo ‘98 Primary Use: The Portuguese National Pavilion was comissioned to host all formal ceremonies and functions, and also have enough exhibition space for simultaneous and diverse events for Expo ‘98.

It currently holds the Maritime Museum, and is used as a multi-purpose event space.

Architect: Structural Engineer: Date completed: Site Location:

Álvaro Siza Vieira Cecil Balmond (Ove Arup and Partners) 1998 Adjacent to the Doca dos Olivais on the bank of the Tagus, Lisbon, Portugal.

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Elemental Form 2D Membrane (tensile), single curvature

Fig. 1.1 Fisheye photograph of canopy and sidewalls

The trademark canopy is formed by the catenary arc of steel cables draped between the porticoes which were subsequently in filled with pre-stressed concrete.

Using the same technology as a suspension bridge, it is designed as a stressed-ribbon structure, wherein the loose cables are stiffened with concrete to eliminate sway and bounce.

In addition to giving the canopy an elegant, clean texture, the painted concrete weighs the roof down to prevent strong drafts from moving or lifting it from below.

While the enormous canopy spans an area of 70 meters by 50 meters, it is a mere 20 centimeters thick.

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Related projects by Álvaro Siza Vieira Figs. 2.1 and 2.2: Leça

Swimming Pool complex / Álvaro Siza Vieira 1966 - Concrete is the primary material of the project. The children’s pool is bound on one edge by a curving concrete wall.

Boa Nova Tea House / Álvaro Siza Vieira 1963 - Sloping Roof Form with concrete structural elements with red brick tile material finish.

Fig. 2.3:

Fig. 2.1

Fig. 2.2

Fig. 2.4: Multifunctional

Hall, Gondomar, Portugal / Alvaro Siza 2007 -Catenary arch roof using cermamic and brick Fig. 2.3

Fig. 2.4 5

Novel design constraints & opportunities • The focal point of the project is a large, open public plaza shaded by a suspended overhead canopy.

• At the time, the purpose of the building after the exposition was unclear, which meant that the architect needed to design for a multipurpose space.

Fig. 3.1

• The architect, emphasizing the connection between the space and the view beyond, wanted to frame the vista of the river with an enclosed and column-free space.

• The project was built on a location with frequent seismic activity.

Figs. 3.1 and 3.2 Design sketches by structural engineer Cecil Balmond Fig. 3.2

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Novel design constraints & opportunities • High wind loads possibly causing uplift.

• Pre-tensioning of the cables to allow for natural catenary to form.

• Large foundations for counterbalance.

• Thinness of the concrete slab vs.

Thickness of the metal cables.

• Building the formwork to match the natural form of the curve.

Fig. 3.3 Wind Rose of Portuguese Pavilion site

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Material Selection To reduce the dead weight of the structure a special concrete was studied, with a mass density lower than 1800 kg/m3 , concrete that must reach a minimum strength LC25 and being to be pumped at distances up to 60 meters.

Lightweight Aggregate Concrete

The formula for this concrete used: • Portland Cement Type Ι 42.5 • Flying Ashes (from Sines Power Plant) • Silica Fumes (MS 610 from MBT) • Natural Sand (Siliceous) • Expanded Clay (LECA 2-4) • Superplastifier (Rheobuilh 561) The total weight of the roof was reduced by approximately 430 tons using lightweight aggregate concrete (LWAC).

Fig. 4.1 Close up of materiality showing ceramics, steel cables and white-painted concrete

Fig. 4.1

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Construction on the pavilion began with the foundations, which consists of piles that run deep into the ground, large footings that will support the fins, and a thick concrete slab between the two footings to further prevent from unwanted inward rotation of the fins, as well as to better distribute gravity loads of the hanging roof into a wider area rather than only the two columns.

Construction Overview

Nine thick concrete fins are then built on top of the footings, They act as anchors in charge of transferring the loads from the roof to the ground, and have to tolerate side loads coming from the cables, and redistribute them down into the footings.

An extensive scaffold system was built to later carry support the formwork. The system already has the pre-calculated curvature of the roof that will be optimal for forces to be balanced in the building. The curvature in the scaffold is slightly deeper than the final intended curve, which will be corrected with post-tensioning.

Fig. 5.1 Construction formwork

The formwork was added to the scaffold. it was made of wooden boards smaller than half- a meter thick to prevent the shape of the curve from looking octagonal. The cables are ethane placed, with an extensive rebar cage. The cables are not tensioned yet.

See Fig. 5.3 (next page) for a step-by-step construction diagram

Fig. 5.2 Fins falsework 9

Construction Overview

Foundations

Formwork

Half stressed cables

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4

7

Fins and anchor slabs

2

5

Cables and reinforcements

Fully stressed cables

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Falsework

Concrete

Remove Formwork

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6

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Fig. 5.3 10

Construction: pouring of concrete

Fig. 5.4 Pouring of concrete

The most challenging part was the pouring of concrete.

Concrete could not be placed rapidly since it could accumulate in the bottom of the slope. So engineers had to start pouring the concrete in a central 2.5 meter wide strip, let it cure for not more than 45 minutes to achieve enough consistency to support the next segment to be poured without spilling but still be able to create continuity within the slab. Four pumps wee used, mixing and distributing 80 cubic meters of concrete per hour to cover the surface of 3900 square meters.

When the concrete cured, engineers started slowly tensioning the cables to achieve optimal equilibrium between a naturally formed slope and enough tension to maintain it, after which the formwork could be removed.

Fig. 5.5 Removal of formwork

See Fig. 5.6 (next page) for a step-by-step diagram of the pouring of the concrete.

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Construction: pouring of concrete

1

2

4

5

3

6

Fig. 5.6

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Internal Forces Fig. 6.3 (next page) demonstrates the force distribution of the inward thrust of the cable structure due to gravity along the canopy. More force is excerted where the canopy meets the side walls.

The canopy exist in tension, with the force load being distributed horizontally along the canopy, then vertically along the side walls/fins.

Fig. 6.1

The foundation pillars exist in compression.

To resist the inward thrust, the sidewalls and the foundation form a moment frame.

To resist tortion of the fins, the sidewalls act as a brace. (Fig. 6.4, pg 13).

Fig. 6.2

Figs. 6.1 and 6.2 basic force calculations 13

Internal Forces

Forces in kN

Fig. 6..3

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Fig. 6..4

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Computational Anal ysis

Fig. 7.1 Load Displacement

Fig 7.2 Material Default

Fig. 7.1 (left) shows the load displacement, i.e., where the structure is most likely to move. The Portuguese Pavilion canopy is most likely to move in the center of the canopy, due to the thinness of the materials, and the fact that it’s furthest away from any anchor points.

Fig. 7.2 (right) shows the material default, i.e., where the structure is most likely to break. The diagonal lines running through the sidewalls show where the force finds the natural triangulation of the material.The overlapping red and blue colors of the canopy indicate differenct materials, the concrete = red (more likely to break), the steel cables = blue (less likely to break). Concrete is considered a semi-brittle material, which makes it more likely to fracture than a ductile material like steel.

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Phsyical model foamcore

wire rope

canopy cast from quickcrete

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Álvaro Siza Vieira

Cecil Balmond

https://www.sizavieira.pt

https://www.balmondstudio.com

Address

Address

Rua do Aleixo 53 2ºAndar 4150-043 Porto Portugal

Contact Tel +351 22 616 7270 geral@sizavieira.pt

Social Media @sizavieira @sizavieira @AlvaroSizaVieira

Contact Info

Unit 13, New Northhouse Canonbury Yard 202-208 New North Road London N1 7BJ UK

Contact Tel +44 20 7043 0651 ln@balmondstudio.com

Social Media @BalmondStudio @BalmondStudio balmondstudio

“Knowing there is a structure, hidden or felt, to the random gives pleasure.”

“I am a firm believer in praxis, and I don’t have much time for

the idea of the loner of genius who does everything all by himself. You need other people as well, at every level.”

-

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Sources “Álvaro Siza – Portugal Pavilion at the Expo ‘98.” Dzv.tv - World’s Creative Videos 🎥, dzv.tv/architecture-works/alvaro-siza-portugal-pavilion-at-the-expo-98.

Arquitectura Viva. “Multifunctional Hall, Gondomar - Álvaro Siza .” Arquitectura Viva, Arquitectura Viva, 7 Jan. 2021, arquitecturaviva.com/works/pabellon-multiusos-9.

Balmond, Cecil. Portuguese National Pavilion Sketch - Cecil Balmond. balmondstudio.tumblr.com/ page/44.

Balters, Sofia. “AD Classics: Leça Swimming Pools / Álvaro Siza Vieira.” ArchDaily, ArchDaily, 6 Aug. 2011, www.archdaily.com/150272/ad-classics-leca-swimming-pools-alvaro-siza.

“Cecil Balmond.” Balmond Studio, www.balmondstudio.com/about-cecil-balmond.php.

De Paula, Felipe Lopes. “Portugal Pavilion, Lisbon. Architect Alvaro Siza Vieira.” Vitruvius, vitruvius. com.br/index.php/jornal/charges/736?page=114.

Dezeenmagazine, director. Álvaro Siza Interview: Expo’98 Portuguese National Pavilion | Architecture | Dezeen, YouTube, 5 Aug. 2019, www.youtube.com/watch?v=ANJQp5xbQpc&t=14s.

“Expo 98 Pavilion of Portugal.” Architectuul, architectuul.com/architecture/expo-98-pavilion-of-portugal.

Gibson, Eleanor. “Creating the Expo’98 Portuguese National Pavilion Was ‘Difficult’ Says Álvaro Siza.”

Dezeen, 2 Aug. 2019, www.dezeen.com/2019/08/02/expo98-portuguese-national-pavilion-alvaro-siza-movie-interview/.

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Image from Web, Portuguese Pavilion. https://i.pinimg.com/originals/a8/fe/51/a8fe5196f3bb0c9acff2c44724cfc049.jpg Langdon, David. “AD Classics: Expo’98 Portuguese National Pavilion / Álvaro Siza Vieira.” ArchDaily, ArchDaily, 23 Oct. 2018, www.archdaily.com/583307/ad-classics-expo-98-portuguese-national-pavilion-alvaro-siza.

Na ja, Ramzi. “AD Classics: Boa Nova Tea House / Álvaro Siza Vieira.” ArchDaily, ArchDaily, 5 Apr. 2013, www.archdaily.com/355077/ad-classics-boa-nova-tea-house-alvaro-siza.

“PRÉMIO LECA DE CONSTRUÇÃO.” 1998, http://www.sta-eng.com/DOCUMENTOS/ARTIGOS/98.05%20 PAV%20PORT_PREMIO%20LECA.pdf “Strength and Beauty: How Cement Made the Portuguese Pavilion Possible.” CEMBUREAU, 9 Apr. 2018, useofcement.cembureau.eu/2018/04/09/strength-and-beauty-how-cement-made-the-portuguesepavilion-possible-2/.

The Arup Journal, vol. 34, no. 2, 1999. https://www.arup.com/perspectives/publications/the-arup-journal/section/the-arup-journal-1999-issue-2

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