Pioneering China s Tallest: Form and Structure of the Ping An Finance Center David Malott, Director, KPF Dennis Poon, Vice Chairman, Thornton Tomasetti
领先中国之巅 : 平安金融中心的形式与结构 David Malott, Director, KPF Dennis Poon, Vice Chairman, Thornton Tomasetti
Carbon Reduction Goal 2010 2015 2020 2025 2030
Structural EE / EC Definitions Embodied Energy (EE): The total primary energy consumed from direct and indirect processes associated with a product or service and with the boundaries of cradle-to-gate. Embodied Carbon (EC): The sum of fuel related carbon emissions associated with the production / manufacture of all materials.
Embodied Energy Extraction/Harvesting Refining Manufacturing Transportation Construction Function of Design & Construction Embodied Energy / Carbon Operational Energy > HVAC > Lighting > Plugloads > Equipment / Machinery > Function of Design & Operation
Embodied Energy / Carbon Subhead Buildings Operational Energy Buildings Embodied Energy
Structural EE / EC Structural + Facade initial Embodied Energy represents 50% or more of the built project Embodied Energy Case Study
EE / EC Factors
Embodied Carbon Case Study Structural EE / EC Structural initial Embodied Carbon represents over 50% of the built project
Design Concepts Efficient Material Use Building / Material Adaptive Reuse Durability, Resilience Adaptability Structural Factors Deconstruction Thermal Efficiency Thermal Mass Integrated Approaches
Structural Factors Building Components Foundations Superstructure Lateral System Façade / Building Envelope Roof
Medium soft soil, site class II~III (China code), D (IBC) Rock is about 30m down 0 m - 20 m - 35 m - 50 m - 60 m - 70 m (-230 ) Shenzhen Soil Profile Silty Clay Fully-weathered Granite Severely-weathered Granite Moderately-weathered Granite Slightly-weathered Granite
Foundation Pile-supported Tower Mat (Octagon Shape) 5m (16.4 ft) thick under the core, 3m (9.8 ft) outside the core C40 (4.9 ksi) concrete 16 hand-dug concrete caissons under the core 5.6m (18.4 ft) diameter with 7.4m (24.3 ft) bellout 30 m (98 ft) long Capacity 344,000 kn (working load) 8 hand-dug concrete caissons under the super columns 7.1m (23.3 ft) diameter with 9.3m (30.5 ft) bellout 30 m (98 ft) long Capacity 543,000 kn (working load) Pile-supported Podium Mat (with tension piles) 1m (3.3 ft) thick 154 hand-dug concrete caissons 1.2m and 1.5m (3.9 and 4.9 ft) diameter 30 m (98 ft) long 1.2m dia. Pile Compression Capacity 9,000 kn, tension Capacity 11,000 kn 1.5m dia. Pile Compression Capacity 14,000 kn, tension Capacity 16,000 kn
Foundation Full Site Plan Tower Mat Podium Mat Secant Pile Wall Contiguous Bored Pile Wall
Tower Foundation plan
SAFE Model for Foundation Design Tower mat thickness is controlled by one-way / two way shear check. Caisson diameter governed by concrete strength, bellout diameter governed by rock bearing strength. Maximum settlement at tower core area ~ 20mm.
zone 8 zone 7 zone 6 zone 5 zone 4 zone 3 zone 2 zone 1 2 Stories 16 Stories 15 Stories 16 Stories 15 Stories 14 Stories 9 Stories 16 Stories Project Stacking 660m MEP/Refuge (Typ.) Tower spire Sky restaurant Observation floor Office 4.5 m (14.8ft) typical floor height basement 10 Stories 5 Stories Retail (zone podium)
Lateral Load Resisting System Core + Outrigger + Mega Frame Core is composite Primarily reinforced concrete walls Embedded steel plates / steel w-shapes 4 two-story Outriggers at MEP/refuge levels engaging super columns Steel truss outriggers Composite concrete + steel super columns Exterior Mega Frame 2-story/1-story high Steel double belt trusses at MEP/refuge levels each zone linking super columns Mega braces between belt trusses
Lateral System Architecture and structure in harmony Z7 Z6 Z5 Z4 Z3 Z2 Z1
Double-height Outrigger Trusses At four zones Within core flange walls 1 st line of seismic defense (yielding) L95-96 L79-81 L48-50 L25-27 Core 6 5 3 1 Outriggers
Super Columns + Double Belt Trusses Steel trusses at seven zones 2 nd line of seismic defense The belt trusses and super columns are designed to take 25% of total base shear in strength Mega Frame 6 5 4 3 2 1 1 story single belt truss 1 story double belt truss 2 story double belt truss 1 story double belt truss 2 story double belt truss 2 story double belt truss L10 1 story double belt truss
Mega Frame Super Columns + Double Belt Trusses + Mega Brace Between belt trusses 2 nd line of seismic defense The mega brace is designed to attract 6% of total base shear in the exterior mega frame based on relative stiffness Mega brace
Floor Framing MEP/Refuge TG TF TC TB 13,180m 30,000m 13,180m T2 T3 T5 T7 13,180m 30,000m Outrigger truss Floor horizontal bracing 13,180m Double belt truss 1.5m wide corner belt truss Moment connected beams at the corner
Core ~32 m x 32 m in plan - Flange wall 1.5m thick to 0.5m - Web wall 0.8m thick to 0.4m thick - Core walls below level 12 have full length steel plates - composite concrete shear wall Link Beam Core Wall Some link beams have embedded steel shapes to satisfy code shear requirement Some walls have embedded steel plates to satisfy code shear requirement Core
Core + Super Columns Column size - 6.0x3.2m (base) - 2.9x1.4m (top) - Embedded steel ratio: 4.0% ~ 6% above ground, 8% in the basement Super Columns Core Concrete super column with embedded steel
Outrigger Trusses Core + Super Columns + 2-story Outrigger Truss Core Super Column Outrigger Truss
Belt Trusses for Mega Frame Core + Super Columns + Outrigger Truss + Double Belt Truss Super Column Double Belt Truss
+ Mega Brace + Chevron Brace Chevron Brace Mega Braces for Mega Frame Primary function of mega brace is to attract enough shear in the exterior mega frame as required by China code Primary function of chevron brace Support recessing corners of the tower Mega Brace Double Belt Truss
Section of outrigger at mechanical level
Exterior megaframe
Lateral structural systems components.
Tower Dynamic Properties Primary Mode Shapes and Periods (T) T = 8.4 s T = 8.4 s T = 3.4 s
Tower Structure Natural Mode Translational mode Torsional mode
Seismic Design Requirements in China Seismic Fortification Intensity = 7 degree (China Code) Frequent earthquake (no damage to building structure) 50 year event (50 year earthquake at 63% exceedance) All members remain elastic Ground acceleration = 35 cm/s 2 3.6% g Medium earthquake (building structures can be repaired) 475 year event (50 year earthquake at 10% exceedance) Core link beams and outrigger trusses allow to yield All other members stay elastic Ground acceleration = 100 cm/s 2 10.2% g Severe earthquake (building structures will not collapse) 2475 year event (50 year earthquake at 2% exceedance) All lateral resisting members can yield in bending, but remain elastic in shear Super column remains elastic (bending & shear) Ground acceleration = 220 cm/s 2 22.4% g
Tower Structure Response under Earthquake
Stiffness Design 50 year wind Wind Design Criteria 34.7 m/s (77.5 mph) for 10 minute gust at 10 m (33 ) Inter-story drift limit = h/500 (China Code Requirement) MAX Tower Inter-story drift = h/542 1 st floor inter-story drift limit =h/2000 (China code Requirement) Tower 1 st floor inter-story drift = h/8561 Tower top deflection = H/775 Strength Design 100 year wind as per China Code 37.1 m/s (83 mph) wind speed Also apply code load combination factor for strength check 100 year Wind Pressure (from RWDI wind tunnel test) 4.0 kpa (84 psf) at tower top 2.5 kpa (52 psf) at ground floor
Integration of Sustainable Design Aspects Form of the Tower Recessed corners Corner setback Rough corner can reduce vortex shedding effects. Reduction in Wind Load= Smaller core and column sizes Less building mass Smaller seismic forces Less Material = Smaller carbon footprint
Integration of Sustainable Design Aspects Major Component 1. Natural Ventilation - Altitude Air intake The building height allows intake of cooler dryer air from the higher altitude, 0.1% savings of the annual energy consumption 2. Heat Recovery System Using warm exhaust air to heat cool fresh air 0.5% savings of the annual energy consumption 3. High Performance Façade (HPF) The detailing, weight and installation is integrated in the structural design with 2% savings of the annual energy consumption, and optimization of window to wall ratio, curtain wall heat conductivity coefficient (U-value), glass shading coefficient and exterior shading design in the curtain wall system. 4. Ice Storage System Structural assimilation of thermal ice storage system and tanks in the basement 4% savings of the annual energy consumption 5. Occupant lighting controls Structural integration of mechanical openings and shafts for lightning control of areas that cannot utilize natural daylight 4% savings of the annual energy consumption
Integration of Sustainable Design Aspects Additional 1. Daylighting, Structural core has been centered within the tower to maximize day light exposure 2. Main structural component such as outriggers and belt truss have been located in low occupied floors (mechanical and refugee floors) 3. Structural podium roof rainwater collectors Structural podium roofs have been designed to incorporate rainwater collectors to reduce consumption and operation for roof landscaping 100% water savings of summer irrigation needs. 4. Recycled Cooling Tower Bleed Off The structural integration of additional pipes reduces portable water use 30% water savings for flushing use.
Additional Integration of Sustainable Design Aspects Material Overview Goal: Minimize environmental impact from material extraction/harvest, manufacture & transport Used Strategies: Use of recycled materials (Steel and Concrete) Use of Cement Substitutes (Fly Ash, Granulated Blast Furnace Slag) Use of salvaged, reused, refurbished Use of local materials Use of certified wood Use of rapidly renewable materials