seattle
central library University of South Australia B.Arch.St, BUIL2006, Assignment 1, 2010. Research Topic: Seattle Central Library (Architects: OMA & LMN) Jet O’Rourke 100005177 Jack Saunders 100100677 Lauren Qvistgaard 110013897
1// STRUCTURAL SYSTEM The Seattle Central Library is a complex building consisting predominantly of five cantilevering platforms. Due to the unconventional nature of this building a complex structural system was engineered.
Image: http://www.archdaily.com/11651/seattle-central-library-oma-lmn, viewed 8 August 2010.
00// BACKGROUND Architect: OMA: Rem Koolhaas & Joshua- Prince Ramus (Partner in charge) Local architects: LMN Architects, Seattle U.S.A Project Design: 1999- 2000 Project Construction: 2001 - 2004 11 floors, plus 1 parking level Total area: 362,987 square feet
Although this building consists of a multitude of structural strategies, the structure primarily consists of load bearing and seismic systems. In terms of load bearing, slanted columns are implemented to carry gravitational loads to the concrete substructure, the unconventional use of slanted columns also counteracts issues such as twisting and deflecting which may occur due to the varied directions of forces created by the cantilevers (Fortner 2001). Loads are directed to these columns or the central core via trusses in the floor plane (Post 2010). The seismic structural system is evident in the lattice like geometry, made of I-Beam steal, which envelops the building (Del Franio 2010), this is known as a diagrid structure. During a seismic event this structural system would provide ample cross bracing.
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2// STRUCTURE + CORE OMA and LMN architects have successfully designed the building’s circulation to include three passenger elevators and one service elevator, thus enabling occupants to efficiently access all eleven platforms of the building, including the underground car park (McKinlay 2003). The emergency fire stairwell is also adjoined to the lift core. The mechanical services are located next to the fire stairs, completing the geometry of the service core. The positioning of the lift core towards southwest quadrant of the building is no coincidence, as the architects postulated another primary way of moving throughout the building. Considering the very nature of the building’s movement, the design provides occupants with the most convenient and straightforward way to access the available resources. The architects deliberately combined a gently sloping pedestrian route, with stairs, ramps, and escalators separately from the elevators and fire stair core (Fortner 2001). A secondary staircase also traverses the entire building. ¬VERTICAL CIRCULATION AXONOMETRIC// (NTS) Drawn by J Saunders, 2010 Original Image: http://www.spl.org/ lfa/central/199912prelimdesign.html, viewed 7 August 2010. ¬¬CORE PLAN SCALE 1:100 Drawn by J Saunders, 2010 Original Image OMA/ LMN Plans: http://www.spl.org/default. asp?pageID=branch_central_building_ floorplans&branchID=1, viewed 7 August 2010.
University of South Australia B.Arch.St, BUIL2006, Assignment 1, 2010. Research Topic: Seattle Central Library (Architects: OMA & LMN) Jet O’Rourke 100005177 Jack Saunders 100100677 Lauren Qvistgaard 110013897
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¬ 1. LOWER STRUCTURAL STUDY 2. UPPER STRUCTURAL STUDY Drawings by Jet O’Rourke, 2010
Original Images: http://www.archdaily.com/11651/seattle-centrallibrary-oma-lmn/, viewed August 5 2010.
∆ DIAGRID STRUCTURE // (NTS)
Image: Ching, FDK, Building Structures Illustrated, Wiley, p269.
≈ NORTH- SOUTH SECTION // 1:250 Drawing by Jet O’Rourke, 2010
Original Image: http://www.spl.org/images/ branch/CEN_floorplans/low_res/N-S-Sec.jpg, viewed 1 August 2010.
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3// STRUCTURE + CORE TYPOLOGY The load bearing system capable of “standing on its own” (Post 2003) is devised of concrete columns and beams on the two lower levels (built into the substructure), and three above in steel thus typical of a Rigid Frame typology (Del Fraino n.d.). Instead of a regular grid of columns, the floating and shifting platforms required skewed columns, and raker columns (Fortner 2001). Platform 4 (which houses the ‘book spiral’), being the hardest working, has additional belt trusses to assist in equalising the load distribution (Ching 2009). Principle architects for the project Rem Koolhaas and Joshua Prince-Ramus central idea of “floating platforms” is further realised by the seismic system identified as a Diagrid typology, composed of I- beam steel fabricated to create a lattice like geometry. The expressed concrete Shear wall core is 650 meters tall and is positioned in the southwest of the footprint. The core carries gravity loads but resists minimal lateral forces (Post 2003). University of South Australia B.Arch.St, BUIL2006, Assignment 1, 2010. Research Topic: Seattle Central Library (Architects: OMA & LMN) Jet O’Rourke 100005177 Jack Saunders 100100677 Lauren Qvistgaard 110013897
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4// STRUCTURAL IMPLICATIONS + LATERAL STABILITY // STRUCTURE + CORE ON THE FLOOR SPACE
// LATERAL STABILITY Lateral stability is achieved in the structure through the building’s braced diagonal grid skin. The diamond like facade connects the platforms, preventing them from failing structurally and tipping. This modular grid works like a giant braced frame, gathering the seismic forces from each platform, carrying them across the grid to the next platform and ultimately to the concrete base (Post 2003). The concrete base also assists in absorbing the torsion in a similar manner.
LEVEL 4 Ω VERTICAL MULLION DETAIL// 1:50 Drawing by Jack Saunders, 2010
Seismic and lateral stability is achieved through the curtain wall, therefore fewer internal columns are required (Olson 2004). This structural system enables the building to meet its programmatic needs in such a way as it is not plagued with columns. The central core has an affect on circulation throughout the floor space as it provides a short cut through the spaces by stair or elevator (Olson 2004).
Original Image: http://lmnarchitects.com/ exploration/seattle_public_library
∆ PLAN DIAGRAMS- DISCHARGE FROM STAIR TO STREET// (NTS) Original Image: http://www.spl.org/images/ branch/CEN_floorplans/low_res/N-S-Sec.jpg, viewed 1 August 2010.
Alternatively it could be argued that the requirements of the floor space actually influenced the choice of structure. The library’s primary functions were assessed and the spatial requirements of the building were established in the earliest stages of the design process, thus the structure was specifically engineered to meet these needs.
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// STRUCTURE + CORE ON THE FACADE Eccentric Bracing, as part of the seismic steel system is employed at the sloping points of the structure (Ching 2009), connecting the platforms without putting additional forces on the curtain wall system (Post 2003). The vertical portions of the buildings periphery structure required attention when detailing the glass façade, as there is no seismic steel used in these areas for structural support (Del Fraino n.d.). For the areas that required attention, a deeper aluminum mullion was designed to withstand the lateral loading while spanning from one floor to the next. So that the difference in structural members could be obscured, the vertical mullion was designed to mimic the shape of the I- beam of the sloping seismic steel (Del Fraino n.d.). The concrete core also helps to absorb any twist in the façade.
University of South Australia B.Arch.St, BUIL2006, Assignment 1, 2010. Research Topic: Seattle Central Library (Architects: OMA & LMN) Jet O’Rourke 100005177 Jack Saunders 100100677 Lauren Qvistgaard 110013897
Ω STRUCTURAL AXONOMETRIC// 1:500 Drawing by Lauren Qvistgaard, 2010 Original Image: http://web.ebscohost.com.ezlibproxy.unisa.edu.au/ehost/d etail?vid=1&hid=111&sid=aeb657a7-3afc-42d6-af8e-4de710aa2ab2%4 0sessionmgr113&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=iih& AN=9618414, viewed 5 August 2010.
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5// CANTILEVERS, LOAD TRANSFERS + DESIGN DETAILS A key component of the Seattle Central Library’s striking design is its stacked cantilevering platforms. The architects shifted the platforms out of vertical alignment with each other by up to 15 metres (Olson 2004). The impressive cantilevers are made possible through a combination of vertical and slanted columns, steel trusses and the seismic diagrid structure (Badders 2004). Loads are transferred across the platform floors and carried to the substructure through the central core, columns, and the braced structure that envelopes the building. The braced structure, along with the slanted columns, also assists in minimising the need for transfer girders.
∆ ‘BOOK SPIRAL’ RAMP// 1:1000 Image: http://www.spl.org/lfa/central/images/sdmay3collectionside.jpg, viewed 9 August 2010.
¬ INTERIOR PHOTOS Image: http://seattletimes.nwsource. com/news/local/library/, viewed 7 August 2010.
≈ LOAD DISTRIBUTION SECTION// 1: 500 Drawing by Lauren Qvistgaard, 2010
INTERESTING + UNCONVENTIONAL ASPECTS OF THE LIBRARY Naturally the building has some interesting aspects with Rem “the dirty Realist” Koolhaas (Rem Koolhaas: A Kind of Architect, 2008) involved in the conceptual design process. OMA have employed vibrant colors throughout the library interior. Stumbling across the extroverted hot-pink curved hallways threaded among the fourth- floor meeting rooms (Olson 2004) appears to symbolise the publics desire to be shocked by the actual as they would in the virtual media world. Additionally, the escalators are bright yellow, providing patrons with useful markers in the voluminous interior (Saieh 2009). The expectation of typical signage is mute within the building (Saieh 2009). However, this lack of direction promotes an exploration of the library’s interior, enabling visitors to map out visual reference points and to piece together the spatial organization of the space. Similar to a parking garage ramp, the 6- degreedescending book spiral creates a 60 metre long accessible and continuous “run” for the non- fiction collection, classified under the 000-999 Dewey Decimal System. To prepare for long term growth, the ramp has been designed to hold 60% more books than it held when it first opened during 2004 (Post 2003). The outer-skin of the library is covered in carabiner clips (Fortner 2001) for window cleaners to negotiate the building. These clips are designed to provide the numerous rock climbers and thrill seekers that live in Seattle a new opportunity to experience a public building. The library also challenges the notion of typical ‘architectural’ materials for a civic building, by employing rip-stop nylon (a parachute-like material) as a ceiling finish in some portions of the interior (Buchanan 2004).
University of South Australia B.Arch.St, BUIL2006, Assignment 1, 2010. Research Topic: Seattle Central Library (Architects: OMA & LMN) Jet O’Rourke 100005177 Jack Saunders 100100677 Lauren Qvistgaard 110013897
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∆ FAÇADE PERSPECTIVE (NTS) Drawing by Jack Saunders, 2010 Original Image: http://seattletimes. nwsource.com/news/local/library/ architecture/, viewed 9 August 2010.
≈ FAÇADE MATERIALITY (NTS) Drawing by Jet O’Rourke, 2010 Original Image: http://seattletimes. nwsource.com/news/local/library/ architecture/, viewed 8 August 2010.
// REFERENCE LIST: Badders, D 2004, ‘Inside the new library’, Seattle Post- Intelligencer 20 May, p. 6. Buchanan, R 2004, ‘Avant-garde architect reinvents Seattle’s new library’, The Seattle Times, 16 May 2004, viewed 11 August 2010, < http://community.seattletimes.nwsource.com/archive/?date=20 040517&slug=rem17>. Ching F 2009, Building Constructed Illustrated, Wiley, New Jersey. Del Franio, S n.d., Seattle Central Library curtain wall design, LMN Architects, viewed 10 August 2010, <http://lmnarchitects.com/ exploration/seattle_public_library>. Fortner, B, 2001, ‘Floors for Seattle’s Central library project appear to float’, Civil Engineering. vol. 71, Iss. 8, pg. 14, viewed 1 August 2010 <http://web.ebscohost.com.ezlibproxy.unisa.edu. au/ehost/detail?vid=1&hid=111&sid=f3411f59-56b6-4ada85a1-6844b8def8e1%40sessionmgr114&bdata=JnNpdGU9ZWh vc3QtbGl2ZQ%3d%3d#db=iih&AN=4978319>. “Rem Koolhaas: A Kind of Architect” 2008, video recording, Arthouse Films. McKinlay B, ‘Pushing the envelope’, Civil engineering,, vol. 73, Iss. 3, viewed 11 August 2010, <http:// web.ebscohost.com.ezlibproxy.unisa.edu.au/ehost/ detail?vid=1&hid=111&sid=aeb657a7-3afc-42d6-af8e-4de710a a2ab2%40sessionmgr113&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ %3d%3d#db=iih&AN=9618414>. Molesworth, C 2004, ‘Seattle Public Library’, Pacific builder & engineer, vol. 110, Iss. 4, p.6. Olson, S 2004, ‘Thanks to OMA’s blending of cool information technology and warm public spaces, Seattle’s Central Library kindles book lust’, Architectural Record, vol. 192, Iss. 7, pg. 88, viewed 9 August 2010, < http://web.ebscohost.com.ezlibproxy.unisa. edu.au/ehost/detail?vid=1&hid=105&sid=d599e52c-ef9e-4ae195b6-4e8632551d04%40sessionmgr111&bdata=JnNpdGU9ZW hvc3QtbGl2ZQ%3d%3d#db=hlh&AN=13860456>. Post, Nadine M, ‘Seattle’s Eccentric ‘Book Behemoth’, ENR: Engineering news-record, vol. 251, Iss. 18, viewed 2 August 2010, <http://web.ebscohost.com.ezlibproxy.unisa.edu.au/ ehost/detail?vid=1&hid=111&sid=33d5008e-2c0c-432e-8949bc14d6458c61%40sessionmgr104&bdata=JnNpdGU9ZWhvc3Q tbGl2ZQ%3d%3d#db=iih&AN=11390231>.
6// FACADE + SUNSHADING The concept of the façade for the library began with the idea of wrapping the entire building in a continuous layer of transparency. The building façade is designed as a curtain wall of aluminium cladding and steel framing in a 1200mm wide diamond pattern. This has the outcome of creating the braced- frame that can provide support in most areas during seismic events (Fortner, 2001).
a suspended, stretched metal mesh for solar shading, while the inner cavity contains krypton gas (Post 2003). The composition of the facade design has been so successful that the building has outperformed Seattle’s energy code by 10 percent (Post 2003). Most of the glass is cleaned twice a year, and more often for surfaces that need it. An atrium rises from the Fourth Avenue level to the 11th floor, where it is topped with glass.
University of South Australia B.Arch.St, BUIL2006, Assignment 1, 2010. Research Topic: Seattle Central Library (Architects: OMA & LMN) Jet O’Rourke 100005177 Jack Saunders 100100677 Lauren Qvistgaard 110013897
With almost 10,000 panels of glazing (Badders 2004), the design is not only rigid but also energy efficient. Panels are either double or triple glazed. Triple-glazed units have an outer cavity containing
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