tall composite structures -...

Tall Composite Structures:Tall Composite Structures: the Right Material, the Right Placethe Right Place, the Right Time

2014 International Wood SymposiumVancouver Convention Centre

Benton Johnson, PE SESkidmore, Owings & Merrill, [email protected]

© SOM 2014

Timber Tower Research Project

Deliverables Available at www.som.com:‐11x17 Sketches: 33 pages‐8.5x11 Report: 68 pages‐3D PDF of Structure

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“Concrete Jointed Timber Frame” System

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Composite Structures

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PHOTO VIA FINEART AMERICA.COMPHOTO VIA FINEART AMERICA.COMPHOTO VIA FINEART AMERICA.COM

Tall Building Structures

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Tall Building Structures ‐Materials

Tall Buildings Prior to 1990:

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Tall Building Structures ‐Materials

Tall Buildings Post 1990:

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The Right Time – Trends Toward Composites

Composite structures are becoming more popular as they use different materials to gain advantages in many aspects:use different materials to gain advantages in many aspects:

Performance Time CostPerformanceLayoutStiffnessM

TimeFabricationHoisting

CostQuantitiesSchedule

MassDynamicsDamping

ConstructabilitySequencing

DurabilityStrength

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The Right Time – Trends Toward Composites

Composite structures are becoming more popular as they use different materials to gain advantages in many aspects:use different materials to gain advantages in many aspects:

Performance Time CostPerformanceLayoutStiffnessM

TimeFabricationHoisting

CostQuantitiesSchedule

MassDynamicsDamping

ConstructabilitySequencing

DurabilityStrength

SustainabilitySustainability

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Design Process

Why Are Composite Structures Successful?

‐>Performance

‐>Schedule

‐>Cost

‐>Sustainability

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Basis of the Research

2013: 7.0 billion Total -- 3.5 billion in Cities

2050: 11 0 billion Total 7 0 billion in Cities2050: 11.0 billion Total -- 7.0 billion in Cities

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Research Project Overview

+417ft

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Structural Materials for Tall Buildings

•Sustainable•High || compr str•High bending str

•High compr str•Complex load paths•‘simple’ construction

•High strength•High stiffness•Small Sizesg g

•Lightweight•MJ/kg = 12.0

p•Heavy•MJ/kg = 2.8

•Lightweight•MJ/kg = 25.4

Energy Souce: Hammond & Johnes, University of Bath© SOM 2014

Performance Requirements of Tall Buildings

G + L G ‐ L

Gravity ManagementCompression Strength Lateral Stiffness

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Performance: Compression Strength

5,100 MJ 11,400MJ 6,100 MJ

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Performance: Axial / Lateral Load Stiffness

5,100 MJ 24,200MJ 13,700 MJ

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Performance: Lateral Load StiffnessT ll B ildi P 1990Tall Buildings Pre 1990:

Tall Buildings Post 1990:Tall Buildings Post 1990:

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Performance: Lateral Load Stiffness

Jin Mao Tower, Shanghai© SOM 2014


Link Beam DeformationLink Beam Deformation

Lateral Load Deformation© SOM 2014

Managing Gravity Loads

G + L G ‐ LG L G ‐ L

Overturning Diagram Lateral Load Tributary Area

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26’‐3”

24’‐2”12.2”

Need ~13.5” th. panelNeed 13.5 th. panelToo much material, not economical

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Floor Structure

We must reduce amount of materials used in the floors what choices do we have?the floors, what choices do we have?

‐Reduce the span?Reduce the span?

‐Add interior columns / walls?

‐Use beams?

‐Boundary conditions?

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Floor Structure

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Floor Structure

We must reduce amount of materials used in the floors what choices do we have?the floors, what choices do we have?

‐Reduce the span?Reduce the span?

‐Add interior columns / walls?

‐Use beams?

‐Boundary conditions

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Floor Connections

Typical Floor Section

Tension Rebar

Typical Framing Plan

Column to Slab ConnectionColumn to Slab Connection

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Floor Connections

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Timber /Concrete Material Properties

135psi

= Side Face

140-710psi

= Cut Face Side Face Cut Face

C=1,400psi C = 425psi

T = 0psi

= Cut Face

T=700psi

C = 2,500psi – 3,400psi

T = 500psi – 2,150 psi

Select Structural SPF 5,000 psi Concrete

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Torsional Behavior

Image from ACI 318

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Concrete Column/Floor Joints

12,000 psip

5,000 psi 5,000 psi12,000 psi

, p , p

12,000 psi

Tall Building Material Schedule

Column is 2.2x stronger than typical floor

Tall Building Material Schedule

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Timber Column/Floor Joints

425 psi Allowable

1400 psi Allowable

Column is 3.3x stronger than typical floor

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Timber Column/Floor Joints

Beam applies tension perpendicular to column grain

425 psi Allowable

1400 psi1400 psi Allowable

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Timber Column / Concrete Floor Joint

1,400 psi Timber Column

C 2,500 psiC=1,400psi

2,500 psi Concrete Joint

C = 2,500 psi (MIN)

1,400 psi Timber Column

The floor is 1 8x strongerThe floor is 1.8x stronger than the column!

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By Volume: 80% Timber, 20% ConcreteBy Weight: 45% Timber, 55% Concrete

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Wall Stress Diagram Net Uplift Detail

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Performance Requirements of Tall Buildings

G + L G ‐ L

Gravity ManagementCompression Strength Lateral Stiffness

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Design Process


‐>Performance

‐>Schedule

‐>Cost

‐>Sustainability

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Construction Time of Tall Buildings

Grade

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Potential Construction Sequence

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Construction Time of Tall Buildings

225 Days Total 230 Days Total225 Days Total

Requirements:1‐Concrete Pump

230 Days Total

Requirements:1‐Concrete Pump1 Concrete Pump

1‐Tower Crane1 Concrete Pump2‐Tower Cranes

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Cost – Materials Comparison

Total Volumetric Mat’ls = 1.12 cu.ft/sfTotal Energy = 150 MJ/SF

Total Volumetric Mat’ls = 1.14 cu.ft/sfTotal Energy = 170 MJ/SF

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Sustainability – Carbon Sequestration

1400

1600

1000

1200

1400

s Ca

rbon

600

800

Met

ric T

ons

0

200

400

Mill

ion

M

01990 1995 2000 2005 2009

Source: USEPA (2010) Inventory of US Greenhouse Gas Emissions andSource: USEPA (2010). Inventory of US Greenhouse Gas Emissions and Sinks, 1990-2008, p. 7-14.

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Effective Use of Timber

Total Mat’l = 1.12 cuft/sfl 0 / f

Total Mat’l = 1.14 cuft/sfl 0 / f

Total Mat’l= 1.30 cuft/sfl 220 / fTotal Energy = 150 MJ/sf

C02 Footprint = 75lb/sfTotal Energy = 170 MJ/sfC02 Footprint = 30lb/sf

Total Energy = 220 MJ/sfC02 Footprint = 20lb/sf

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Mountain Pine Beetle – 200+ billion board‐ft since 1997 in BC(source: BC Forest Service)(source: BC Forest Service)

How can this material be used most effectively?How can this material be used most effectively?

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Using SOM proposed composite system, 200b bd‐ft = 20.8 b SF of high‐rise

Using SOM proposed all‐timber system, 200b bd‐ft = 13.7 b SF of high‐rise

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Ave Material Usage = 1.12 cuft/sfAve Energy Consumption = 170 MJ/sfAve Carbon Footprint = 30lb/sf

Using SOM all‐timber & concrete systems, 200b bd‐ft = 20.8 b SF of high‐rise

Ave Material Usage 1 25 cuft/sftAve Material Usage = 1.25 cuft/sftAve Energy Consumption = 200 MJ/sfAverage Carbon Footprint = 40lb/sf

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Tall Composite Structures:Tall Composite Structures: the Right Material, the Right Placethe Right Place, the Right Time

Thank You & Questions

© SOM 2014

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