UAE Pavilion

Novum Structures

USA, China, China, France, Germany, India, Singapore , Turkey, UAE, UAE, United Kingdom

The Freeform Structure of the UAE Pavilion at the Shanghai EXPO 2010 Novum Structures

www.novumstructures.com www.nov umstructures.com

Novum Structures

USA, China, China, France, Germany, India, Singapore , Turkey, UAE, UAE, United Kingdom

The Freeform Structure Structure of the UAE Pavilion at the Shanghai EXPO 2010

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Design & Build Specialty Contractor for Architectural Steel, Cable, Glass & Membrane Structures

Grid Shell & Cable Structures

Wrigley’s R&D Center Chicago, USA

Seattle Airport, USA Novum Structures www.nov www.novumstructures.com umstructures.com

Freeform Freeform Structures

Dali Museum St. Petersburg, USA

Yueda 889 Shopping Mall Shanghai, China

Structures with ETFE Cladding

Tours Shopping Mall, France

Old Castle Dresden, Germany

Novum Structures

USA, China, France, Germany, India, Singapore , Turkey, UAE, United Kingdom

The Freeform Structure of the UAE Pavilion at the Shanghai EXPO 2010

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Novum Structures International Network

Holding Company:

Menomonee Falls, WI San Francisco, CA Dallas, TX

Diss, UK Farnham, UK France

Chicago, IL

Sangerhausen, Germany Wurzburg, Germany Istanbul, Turkey Beijing, China

Sarasota, FL Dubai UAE Bangalore, India Singapore

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Selection of Novum Component Systems for Building Structures & Envelops

Novum Structures www.novumstructures.com BK-System KK-System BB-System

FF-System

CCG-System

ECG-System

AFP-System

SSM-System


2. Pavilion Structure 3. Grid Shell Geometry 4. Freeform Grid Shell Node Connector 4.1. 4.2. 4.3. 4.4.

Node Connection Bending Stiffness and Capacity Tests Numerical Calculation of Node Connection Bending Capacity Analytical Calculation of Node Connection Stiffness Finite Element Analysis of Node Connection

5. Structural Analysis 5.1.

Global Stability Analysis

6. Fabrication and Installation

Novum Structures

www.novumstructures.com

Picture: Foster + Partner


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Design Architect: Design Engineer: Architect & Engineer of Record: General Contractor: Contractor Freeform Structures:

Foster + Partner, London, UK Halvorson & Partners, Chicago, USA ECADI East China Architectural Design & Research Institute Co.Ltd. CSCEC China Construction Industrial Equipment Installation Co. Ltd. Novum Structures China Co. Ltd. in cooperation with Novum Structures LLC (USA) & GmbH (Germany)

Pictures: Foster + Partner

Novum Structures



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Pavilion shape is resembling 3 sand dunes as natural formations typical for UAE deserts like the Rub Al Khali (aka “the Empty Quarter”) with distinct dune features – gradually curved windward sides, sharp ridges and almost flat leeward sides Height of the southern dune is 20 m, height of northern dunes is about 18 m Pavilion has almost circular footprint with a diameter of about 65 m After the EXPO 2010 the pavilion will be disassembled & moved to Saadiyat Island, Abu Dhabi, UAE


Novum Structures



1. Introduction

3. Grid Shell Geometry 4. Freeform Grid Shell Node Connector 4.1. 4.2. 4.3. 4.4.





Novum Structures




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Southern halves of dune shapes (“windward sides”) are single layer freeform grid shell structures Northern halves of dune shape (“leeward sides”) are inclined, straight -beams (horizontally braced) Dune shapes are subdivided and supported by a central spine structure with portal frames every 6 m Northern dune shape is additionally supported by 2 -beams in inflection zone of grid shell Crescent shaped canopies with “tension ring belt” edge beams & entrance wall structures are enclosing the northern and southern buidling entrances Dune ridges are made of curved, large diameter pipes Pavilion structure is supported on reinforced concrete stripe foundation

Novum Structures



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Conceptual grid shell design by Halvorson & Partners was calling for SHS profiles 200x200x6 mm To avoid extremely large node connectors , profiles were changed to RHS 240x80x8 (steel Q345) Grid shell members are interconnected with concealed bolted Novum FF node connectors in order to enable the diassembly, shipment and reuse of the complete pavilion structure after the EXPO Cladding is supported by posts, bolted to the top surface of the node connector

Novum Structures



1. Introduction 2. Pavilion Structure

4. Freeform Grid Shell Node Connector 4.1. 4.2. 4.3. 4.4.





Novum Structures




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2 basic methods to develop a grid on continuous surfaces: Surface Grid Development Surface Partitioning Method

Planar Projection Method •

Planar grid is projected on continuous surface and manually improved where needed (suitable for surfaces with small curvature)

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Boundary lines get subdivided into portions of similar length, thus creating “orthogonal” auxiliary grid on surface Final grid is tied into this auxiliary grid


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Grids created by those 2 methods have different specific properties: Surface Grid Development Surface Partitioning Method

Planar Projection Method Resulting grid is usually evenly spaced and balanced  Planar grid projection is not considering boundary lines, thus creating problematic grid zones along boundaries 

Southern dune grid created with planar projection

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Grid along boundaries is unproblematic  Resulting grid can appear slighly more irregular, although this strongly depends on the current perspective of the viewer 

Southern dune grid created with surface partitioning


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Final step of grid development is the identification of local coordinate systems for nodes and members based on the given grid panels: 1. normal vector of a member is the average normal vector of the 2 adjacent grid panels 2. normal vector of a node is the average normal vector of all adjacent grid panels

Normal Vector Node

Normal Vector Panel

Normal Vector Member

Normal Vector Panel Normal Vector Member Normal Vector Node

Novum Structures



1. Introduction 2. Pavilion Structure 3. Grid Shell Geometry





Novum Structures



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Concealed bolted Novum FF node connectors, used for grid shell member connections, consist of: - 2 forged discs 200x85 mm (steel #45) with individually machined faces as required by geometry - each machined face has one threaded hole to receive a M24 or M27 bolt - precision cast steel adapters (steel GS-20Mn5V) with top & bottom hole, welded to member ends - concealed & pretensioned socket head bolts 10.9, fixing the end adapters to the 2 n ode discs The semi-rigid behaviour of these bolted node connections has to be adequately considered in the structural model - typically as a rotational spring stiffness at the end of each grid shell member

Novum Structures



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4-point bending test (stiffness & capacity)

）

（

(M24 bolts)

（

）

1

Bolt

127 kN

76.8 kNm

2

Bolt

128 kN

77.4 kNm

3

Bolt

129 kN

78.0 kNm

Novum Structures



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Bending moment capacity of the node connection as a function of the axial connection force was determined using an iterative numerical calculation method assuming planarity of member end section [Space Structures 5, Telford Publ. 2002, p. 759-773]

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Initial parameters:

it  0 , n

Strain parameters:

z

it



it

mz



Norig , my

it

E  Jz

,

y

it



my

 Myorig

E  Jy

,

n


it



 Mzorig

it

n

EA

Mz

YE S



Novum Structures

o

it

> Compression stress in the connection profile / Element force & moments

 

(M24 bolts)

, mz

it

> Tensile stress in the bolts / Bolt force & moments Calculations were performed for 3 limit state > Internal connection force & moments : N , My , Mz conditions: elastic, plastic capacity and failure limit > Deviations from given force & moments: N , My , Test results are conservatively close to the failure limit bending moment All deviations 0 ? it = it + 1

•

it

it 1

n

it

 N

it

, my

it 1

N Oit

 my

 My

it

, mz

it 1

Stress distribution determined !

 mz

it

 Mz

it


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The node connection stiffness can be determined using the measured load-displacement curves The measured total mid span deflection is obviously a combination of flexural deformation of the specimen and rotational deformation of the node connection: - total measured mid span deflection, m  - flexural mid span deformation of the specimen, m  M  l     - bending moment at node connection, Nm M 2  K l - span, distance from support to support K - rotational node connection stiffness of (Nm/rad) Total

Flex

Rot

Total

Flex

Rot

Rot

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The flexural mid span deformation of the specimen can be calculated as follows:  Flex 

M 24 EI

 3l  4a 2

2



E

I

a

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The rotational connection stiffness can be determined using a combination of the above formulas: K Rot

M  l

 2

• •

- modulus of elasticity of steel, N/m 2 - moment of inertia of tube section, m4 - distance of load introduction point from support, m

M  2 2  Total  24 EI  3l  4a 

The average total mid span deflection in the tests with M24 bolts was 18.5 mm at 100 kN ram load (equivalent to 60.5 kNm connection bending moment) The corresponding node connection stiffness is 16110 kNm/rad.

Novum Structures



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As an additional verification of the numerical and analytical node connection parameter calculations, a finite element analysis of the test specimen was performed The observed mid span deflection of the FE model is only 80% of the average measured value, due to little initial settlements of the real specimen This ratio was then used to calibrate the FE model of the node connection used in the structural analysis

Novum Structures



1. Introduction 2. Pavilion Structure 3. Grid Shell Geometry 4. Freeform Grid Shell Node Connector 4.1. 4.2. 4.3. 4.4.



Novum Structures




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The conceptual structural analysis by Halvorson & Partners had to be adopted by ECADI considering local regulations and all modifications made during the construction phase A major update of the structural analysis was required du to the following: - member profiles changed from SHS 200x200x6 to RHS 240x80x8 in order to minimise node size - Halvorson assumed fully rigid node connections – changed to real semi-rigid connection stiffness A meaningful structural model of the grid shell portions has to include all other parts of the pavilion structure as well – therefore ECADI and Novum closely coordinated their structural models and performed the analysis simultaneously (ECADI used SAP2000, Novum used Dluba l RStab)

Novum Structures



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The Chinese guideline JGJ 61-2003 “Technical Specification for Lattice Shells” requires that the ratio of the critical global buckling load to the governing service load combination is at least 4.2 (determined in a linear-elastic buckling analysis of the structure considering global imperfections) ECADI established in their structural analysis the governing load cases for the different grid shell portions – for the southern dune this combination was DL + WL45˚ + 0.7 LLroof + 0.7 Tincr (see below) The global grid shell imperfections were generated by scaling the first buckling mode to a maximum imperfection value of L/300 = 66 mm (L: span) The ratio of the critical buckling load to the governing service load combination was finally 4.6 for the southern dune grid shell

Novum Structures



1. Introduction 2. Pavilion Structure 3. Grid Shell Geometry 4. Freeform Grid Shell Node Connector 4.1. 4.2. 4.3. 4.4.



Novum Structures





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Freeform grid shell structures in general (except of small ones) cannot be drawn and fabricated using conventional methods due to time, cost, manpower and reliability constraints Instead, interconnected parametric component models for all parts of the members and node connections have to be developed – both in CAD and CAM software programs used Then instead of conventional drawings only relevant data and very few parametric drawings are needed to design and fabricate all grid shell components

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Node component fabrication: • CNC model data transfer & check • CNC machining and marking • Quality control • Crating and shipment

Novum Structures



Member fabrication: • Parametric drawing data transfer & check • Length and hole cutting • Adapter welding • Painting • Crating and shipment

Novum Structures



Novum Structures


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UAE Pavilion

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