Steve McKechnie Associate Director, Arup

New structural technologies deliver value in tall building design

Introduction

Steve McKechnie

3

Three New Structural Technologies:

•  What are they?

•  How do they work?

•  Are they worth it?

Introduction

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•  Height 187m •  GIA 58,000m2 •  NIA 36,100m2 •  37 Tower Floor Levels •  2½ Basement Levels •  Steel Tonnage 110kg/m2

•  London Clay piles •  Client: WR Berkley

Developments •  Architect: Kohn Pedersen

Fox •  Engineers: Arup •  Completion 2017

‘The Scalpel,’ 52 Lime St

Structural Engineering

Steve McKechnie

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Design Drivers

•  Client aesthetic aspiration and expression of brand values

•  Value of lettable space

•  Planning Approval

7 Plan form

8 Core interrupts lettable space

9 Open floor plate

10 Open floor plate

11 North Façade inclined to respect views of St Paul’s

12 Eccentricity of primary structural element

13 Primary Elements

14 Primary Elements

15 Primary Elements

16 Primary Elements

17 Primary Elements

18 Primary Elements of structure

Core Prestressing

Steve McKechnie

20 Force from inclined columns

21 Standard Approach: Thicker core walls

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Tendon Layout Core Stressing at ‘The Masterpiece’ Hong Kong

Top Anchorage detail Grouting at “The Masterpiece,” Hong Kong

Core Prestressing

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•  Saves 5000 ft2 of NIA

•  And 1800m3 of concrete

•  Worth £5,200,000 •  plus 1000t eC02

Tendon Layout Core Stressing at ‘The Masterpiece’ Hong Kong

Grouting at “The Masterpiece,” Hong Kong

Core Prestressing

Integral damping

Steve McKechnie

25 Wind Induced Accelerations

26 Wind Induced Accelerations

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Increase Frame Stiffness: More than 2500t of steel

Standard Approaches

Tuned Mass Dampers: £2.5M plus 1000ft2 of NIA

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Dampers being installed at 250 West 55th St, New York

Damper testing for Pinnacle Project

Integral dampers

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Dampers being installed at 250 West 55th St, New York

Integral dampers

•  Damper cost < £200,000

•  Saving of > 2500t of steel

•  Saving of £4,800,000 •  and 4700t eC02

Optimisation through BIM

Steve McKechnie

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Structure

BIM workflow SMEP model

BIM Process

32 1500 composite floor beams to design

33 Optimised design through BIM

•  Floor steel 45kg/m2

•  Saving of 12kg/m2

•  GIA 58,000m2 => 700t steel

•  Saving of £1,400,000 •  and 1300t eC02

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Three New Structural Technologies:

•  Core Prestressing

•  Integral Damping

•  Optimisation through BIM

Summary

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Arup’s use of new structural technologies delivered between £5M and £10M of value and savings to the client

Thank you

36 The Scalpel: 52 Lime St

Additional Slides

Steve McKechnie

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Steel GA at level 2 Elevations

Steelwork Drawings

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•  Gherkin: 180m, 55mm, 0.26Hz

•  Heron: 200m, 500mm, 0.16Hz

•  Scalpel: 190m, 350mm, 0.2Hz

Wind Induced Accelerations

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41 Alternative load path analyses