PRECAST IN SEISMIC AREAS
Project presentation
Content • Basic facts • Industrialised construction in China- project – – – – – – –
Target Architecture Structural design Connections / detailing Precast components Comments from international experts Project material
• Reference precast buildings from major earthquake areas • Conclusions
BASIC FACTS
World seismic map
Basic Principles The intensity of an earthquake is a measurement of the observed damage at a particular location. This intensity will vary with distance from the epicenter and depends on local ground conditions.
Fracture mechanisms
In seismic design ductile structures are preferred
Precast Seismic Systems Typical ductile connections
Precast Seismic Systems
Industrialized building construction in China – Project
Industrialized building construction for China Target of the project • To develop: • A building system for industrially manufactured multi storey apartment building – based on precast concrete building method – based on Nordic (Scandinavian) experience – modern Nordic industrialized building technologies (including building services, thermal insulation, ecology, fast assembly, quality, design etc.) – design according to Chinese needs and regulation (including seismic evaluation).
Project phases
Local regulation
Urban planning
Project phases Floor layout design
Architecture / outlook
Project phases Structural design
Detailing
30.12.2013
Seismic Training 2014 / Olli Korander
Project phases • • • • •
Fact book about Seismicity and Precast Sustainability Building services Cost evaluation Checking by experts from China and New Zealand
• Precast systems for Seismic Areas
Project Team • Elematic Oy • Peikko Group • JKMM Architects • Sweco – Finnmap Consulting – Airix Building services – Sweco PM
• Suadi ( China ) • Holmes Consulting ( New Zealand ) • TEKES, the Finnish Funding Agency for Innovation
Architecture
Urban planning
Type
High rise Housing
Central City(inside outer Ring Road) Inside inner Outside circle inner circle D 25%
FAR 2.5
D 25%
FAR 2.0
Beyond Central City(outside outer Ring Road) New town Central Common Village village others D FAR D FAR D FAR 25% 1.8 30% 1.0 30% 1.0
Architecture / floor layout
Architecture
Architecture / flexibility
Architecture / variations
Project characteristics Section
Description
Site Location
China, Shanghai
Ground type
Hard to Stiff Clay
Occupancy
14-Floors Precast Residential Building
Building area
5390 m²
Construction type
Precast concrete elements
Structural system
Shear Wall system
Floor system Lateral system Foundation system
Design process tools
PC Half Slab+ cast in situ Concrete Topping - Diaphragm Uncoupled wall system Piled foundation
Building Information Modeling (BIM) Interoperability of Tekla structures, SCIA Engineering, RFEM Dlubal, AUTOCAD, and Excel.
Cross-sections
Structural system Precast large wall panel / shear wall system • • • •
Reference material: Chinese codes and standards Eurocode 8, Eurocode 2 fib Commission 6 : Precast concrete buildings in seismic areas - Practical aspects • PCI: Seismic design of Precast / Prestressed Concrete Structures
Shear wall system Shear wall ( large panel ) systems provide sufficient horizontal stability with proper arrangements of the walls in all directions.
Calculations PGA* 0,05 g ( low ) PGA 0,20 g ( high )
1. 3D Modeling View 2. Analysis and design 3. Floor design process 4. Wall and joints design process 5. Structure reactions 6. Eigenvalue Analysis 7. Structural Displacement and Damage Limitations 8. Shear walls and Diaphragm results.
PGA= peak ground acceleration
Load bearing walls, floor lay-out
Structural system Cast-in-situ Vertical connection
Precast Solid Partition Wall 200 mm
Balcony Solid precast Wall 200 mmm Horizonatal wall connection
Sandwich Precast Wall Element Bearing shell 160 mm Insulation 100 mm Facade 70 mm
Balcony Soild Slab 220mm
Structural system / seismic forces
Seismic forces in low and high seismicity FL 1st Floor 2nd Floor 3rd Floor 4th Floor 5th Floor 6th Floor 7th Floor 8th Floor 9th Floor 10th Floor 11th Floor 12th Floor 13th Floor 14th Floor FL 1st Floor 2nd Floor 3rd Floor 4th Floor 5th Floor 6th Floor 7th Floor 8th Floor 9th Floor 10th Floor 11th Floor 12th Floor 13th Floor 14th Floor
Height [zi] m 2,8 5,6 8,4 11,2 14 16,8 19,6 22,4 25,2 28 30,8 33,6 36,4 39,2
Seismic shear in X_ 0.2g kN 5266.99 4220.53 4675.42 4441.77 4187.34 3777.34 2999.84 3280.4 2257.49 2529.3 2106.85 1646.47 1093.84 483.32
Seismic shear in X_ 0.05g kN 1938.13 1920.21 1889.21 1841.21 1750.98 1648.44 1535.76 1411.56 1278.16 1133.56 973.44 789.21 570.32 311.95
Height [zi] m 2,8 5,6 8,4 11,2 14 16,8 19,6 22,4 25,2 28 30,8 33,6 36,4 39,2
Seismic shear in Y_ 0.2g kN 4420.1 4097.44 3473.93 3242.59 2951.62 2805.92 2672.42 2630.34 2478.32 2324.55 2060.16 1653.68 1164.41 512.63
Seismic shear in Y_ 0.05g kN 1797.13 1745.18 1743.96 1673.21 1587.79 1495.15 1396.68 1299.87 1197.38 1086.03 956.93 795.76 595.13 327.28
Calculations 0.2g Mode 1
Mode 2
Mode 1
Mode 2
0,769 sec [X-Dir.]
0,241 sec [X-Dir.]
1,069 sec [Y-Dir.]
0,560 sec [Y-Dir.]
< XDir>
< YDir >
0.05g Mode 1
Mode 2
Mode 1
Mode 2
0.403 sec [X-Dir.]
0.123 sec [X-Dir.]
0.441 sec [Y-Dir.]
0.300 sec [Y-Dir.]
< XDir>
< YDir >
Material properties Eurocode
Chinese PC Solid Slab, PC Stair, PC Parapet
CONCRETE
C40 Eurocode
Chinese PC Wall (Solid Wall, Sandwich Wall)
C30
C30/37 Eurocode
Chinese The Concrete for Joint Casting
C30
C30/37 Eurocode
Chinese Topping Concrete
C30
C30/37 Eurocode
Chinese Foundation (Pile Cap)
C40/50
C30
PC Wall PC Solid Slab PC Stair
fyk = 500MPa
Strand (PC Solid Half Slab)
fpk = 1,860MPa (fp0.1k = 1,630 Mpa)
REINFORCEMENT & STRAND
C30/37 Sulfate Resisting Cement
Connections
Connections
Connections
Connections
Connections
3-D Modeling / building
Modeling / floor
Modeling / wall element
Project results
Checking, China Suadi
Checking, New Zealand Holmes Consulting Group
FE-Models PKPM MODEL BY SUADI
RFEM MODEL BY FINNMAP
ETABS MODEL BY HOLMES
• • • •
Balcony is added as distributed load on floor. Rigid diaphragm floor is used. Walls are not released. (The structures analyzed more or less as cast in situ concrete).
• • •
Balcony is added as attached element to the structure. Rigid diaphragm floor is used. Walls are not released. (The structures analyzed more or less as cast in situ concrete).
• •
Balcony is added as attached element to the structure. The balcony structure is released from mean structure. Rigid diaphragm floor is used. Wall are released. (The precast connections were considered in analysis).
Some comparisons
Some comparisons
Recommended reinforcement principle
Overlapping stirrups RECOMMENDED
Recommended reinforcement principle
Main findings of checking • Loadings and deformations close to each others • Balanced floor lay-out, amount and location of shear walls makes design easier and reduces forces and deformations • The latest findings of reinforcement principles of details, increase ductility, anchoring of bars are implemented • Use of more ductile steel improves the structure
Conclusion • Seismic loads and actions are large compared to non-seismic situations • Seismic design is more demanding than normal structural design • Seismic design expertice is often local • Local codes follow often the principles of cast in situ • Precast buildings can be used in different seismic conditions • The design of connections is the key point