1 Bligh Sydney Modelling Project
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1 Bligh Sydney Modelling using Strand 7 (Earthquake Analysis) Zhong Yan Yu, Teng Fong Ho, Peng Yu Huang Supervised by Peter Ansourian, Joseph Yeow, and Fernando Alonso-Marroquín School of Civil Engineering FACULTY OF ENGINEERING & INFORMATION TECHNOLOGIES Objectives 1. To create a simplified finite element model of 1 Bligh Sydney using Strand 7 software program and simulate earthquake loading using Natural Frequency Solver and Spectral Response Solver. 2. To investigate the response of the 1 Bligh Sydney model (including deflections, reactions and internal actions) under earthquake situation with the magnitude of 1/2500 year. 3. To assess whether the different elements in 1 Bligh Sydney has satisfied the strength requirements stipulated in AS 1170.4 -02007. 4. To evaluate the overall accuracy of the Strand 7 results. Discussion and Conclusion Under the situation of 1/2500 year earthquake, SPA (Spectral Response Analysis) in Strand 7 shows the overall deflection of 1 Bligh Sydney is acceptable (within 100mm) The overall building structure has not failed although certain parts of the concrete experience cracking problems SRSS and CQC methods produced almost identical results in terms of deflections and stresses • indicative of the satisfactory separation among different frequency modes taken into consideration Whereas Linear Static methods produce generally larger deflection and stress results → more conservative Strand7 is limited to providing a preliminary estimation of stresses, reactions and deflections due to the questionable assumptions made in spectral response solver such as linear material properties Results Total Mass Participation Factor • X: 92.74% > 90% ✓ • Y: 91.32% > 90% ✓ Natural frequencies of 20 modes considered 4 Importantly Distributed Modes Background • 1 Bligh Sydney is a 30-storey reinforce concrete structure with two vertical shear cores. This139 metre- high office tower located in the CBD of Sydney metropolis area is also the first high-rise structure to be awarded the "6 Star World Leadership” certificate of the Australian "Green Star" eco-standard. Methodology Strand7 Model Building • The three-dimensional view of the finished floor plan as compare with the original building floor plan Methodology cont. Detail on each floor • Same dimensions were used on 30 levels • The 3-D model undergoing earthquake analysis in strand7 No. Component Representation in Strand 7 Modelling Element Type in Strand 7 Number per Floor Important Dimensions 1 Slab Surrounding the Trapezoidal Hollow Section Red Plates Quad 8 NA 350 mm Thickness 2 Slab away from the Trapezoidal Hollow Section Blue Plates Quad 8 NA 150 mm Thickness 3 Column Green Circles Quad 8 12 1500 mm Diameter 4 Shear Core Green Plates Beam 2 2 400 mm Thickness 5 Beams Connecting the Thick and Thin Slabs Pink Bands Beam 2 1 Depth: 500 mm Width: 550 mm 6 Beams Along the Radius of the Ellipsis Green Bands Beam 2 9 Depth: 350 mm Width: 1800 mm 7 Beams Along the Inner Contour of the Floor Plan Dark Blue Bands Beam 2 1 Depth: 600 mm Width: 1300 mm 8 Beam Along the Outer Contour of the floor Plan Light Blue Bands Beam 2 1 Depth: 600 mm Width: 1500 mm Load case Combinatio n Load Case 1 Combination Load Case 2 Combination Load Case 3 (Factor) Combination Load Case4 (Factor) Live Load 0.3 0.3 0.3 0.3 Dead Load 1 1 1 1 Earthquake (X direction) 1 1 0.3 0.3 Earthquake (Y direction) 0.3 -0.3 1 -1 Different Load Cases Considered Analyses Natural Frequency Solver Determine Frequencies and modal shapes Spectral Response Analysis Solver Spectral Response Curve (with S.F.) Equivalent Static Linear Analysis 1 Bligh Sydney belongs to EDC III, linear static analysis is not required for the earthquake analysis. However it is still carried out to compare with the results from Spectral Response Solver to obtain more insight and reliable results. Maximum Stress in all 4 Load Cases Summary of Results in Different Analyses Mode Frequenc y(Hz) Mod e Frequenc y(Hz) Mod e Frequenc y(Hz) Mod e Frequenc y(Hz) 1 0.2726 6 1.994 11 2.868 16 3.115 2 0.2816 7 2.290 12 2.918 17 3.161 3 0.6628 8 2.396 13 2.981 18 3.164 4 1.075 9 2.589 14 3.006 19 3.17975 5 1.317 10 2.650 15 3.110 20 3.17976 Deflection Under Combined Load Part of Buildin g The Worst Linear Combination Cases Tensile/ Compressive Maximum Stress (MPa) Direction (Global) Column Case 4 Tensile Stress 5.29 ZZ Case 3 Compressive Stress -24.4 ZZ Beam Case 1 Tensile Stress 18.7 NA Case 1 Compressive Stress -18.7 NA Shear Core Case 4 Tensile Stress 17.3 ZZ (+z surface) Case 1 Compressive Stress -29.8 ZZ (-z surface) Slab Tensile Stress YY (-z Compressive Stress Analysis Method Max Deflections in Beams D(XYZ) (mm) Max Deflection s of Plates D(XYZ)(mm) Max Fibre Stress of Beams (MPa) Max Fibre Stress of Plates (MPa) SRSS 28.6 28.7 2.45 4.78 CQC 28.5 28.6 2.39 4.85 ESA 36.3 36.4 2.2 3.45 %Difference between SRSS and CQC -0.35% -0.35% -2.45% 1.46% %Difference between SRSS and ESA 26.92% 26.83% -10.20% -50.00% Reference: 1) Joint Standards Australia/Standards New Zealand Committee BD-006 (2007)AS1170.4-2007 Earthquake Actions in Australia, Second Edition, GPO Box 476, Sydney, NSW 2001, Australia: Standards Australia. 2) Strand7 Webnotes (2013) ST7-1.10.20.9 Spectral Response Analysis , Available at:www.strand7.com (Accessed: 31-May-2013 ). 3) Strand7 Webnotes (2013) ST7-1.10.20.10 Modal Mass, Stiffness and the Mass Participation Factor , Available at:www.strand7.com (Accessed: 31-May- 2013 ). 4) Strand7 Webnotes (2013) ST7-1.40.35.22 AS1170.4-2007 Earthquake Analysis in Strand7 , Available at:www.strand7.com (Accessed: 31-May-2013 ). 5) Strand7 Webnotes (2013) ST7-1.10.20.6 Natural Frequency Analysis with loading, Available at:www.strand7.com (Accessed: 31-May-2013 ). 6) Strand7 Webnotes (2013) ST7-1.10.20.9 Spectral Response Analysis , Available at:www.strand7.com (Accessed: 31-May-2013 ). 7) Joint Standards Australia/Standards New Zealand Committee BD-002 (2009)AS3600-2009 Concrete Structures, Second Edition edn., GPO Box 476, Sydney, NSW 2001, 8) Australia: Standards Australia. 9) Hancock, G., Clarke, M., & Wilkinson, T. (2006). Steel Structures 1: Lecture Notes. Sydney: School of Civil Engineering, The University of Sydney. 10) Natural Frequency Solver. (n.d.). Retrieved May 31, 2013, from Strand7: http://www.strand7.com/html/naturalfrequency.htm 11) Spectral Response Solver . (n.d.). Retrieved May 31, 2013, from Strand7: http://www.strand7.com/html/spectralresponse.htm
Transcript of 1 Bligh Sydney Modelling Project
1 Bligh Sydney Modelling using Strand 7 (Earthquake Analysis) Zhong Yan Yu, Teng Fong Ho, Peng Yu Huang
Supervised by Peter Ansourian, Joseph Yeow, and Fernando Alonso-Marroquín School of Civil EngineeringFACULTY OF ENGINEERING & INFORMATION TECHNOLOGIES
Objectives 1. To create a simplified finite element model of 1 Bligh Sydney using Strand 7 software program and simulate earthquake loading using Natural Frequency Solver and Spectral Response Solver. 2. To investigate the response of the 1 Bligh Sydney model (including deflections, reactions and internal actions) under earthquake situation with the magnitude of 1/2500 year. 3. To assess whether the different elements in 1 Bligh Sydney has satisfied the strength requirements stipulated in AS 1170.4 -02007. 4. To evaluate the overall accuracy of the Strand 7 results.
Discussion and Conclusion Under the situation of 1/2500 year earthquake, SPA (Spectral Response Analysis) in Strand 7 shows the overall
deflection of 1 Bligh Sydney is acceptable (within 100mm) The overall building structure has not failed although certain parts of the concrete experience cracking problems SRSS and CQC methods produced almost identical results in terms of deflections and stresses
• indicative of the satisfactory separation among different frequency modes taken into consideration
Whereas Linear Static methods produce generally larger deflection and stress results → more conservative Strand7 is limited to providing a preliminary estimation of stresses, reactions and deflections due to the questionable
assumptions made in spectral response solver such as linear material properties
ResultsTotal Mass Participation Factor• X: 92.74% > 90% ✓• Y: 91.32% > 90% ✓Natural frequencies of 20 modes
considered
4 Importantly Distributed Modes
Background • 1 Bligh Sydney is a 30-storey reinforce concrete
structure with two vertical shear cores. This139 metre-high office tower located in the CBD of Sydney metropolis area is also the first high-rise structure to be awarded the "6 Star World Leadership” certificate of the Australian "Green Star" eco-standard.
MethodologyStrand7 Model Building• The three-dimensional view of the finished
floor plan as compare with the original building floor plan
Methodology cont.Detail on each floor• Same dimensions were used on 30 levels
• The 3-D model undergoing earthquake analysis in strand7
No. Component Representation in Strand
7 Modelling Element Type in Strand 7
Number per Floor
Important Dimensions
1
Slab Surrounding the Trapezoidal Hollow Section Red Plates Quad 8 NA 350 mm Thickness
2
Slab away from the Trapezoidal Hollow Section Blue Plates Quad 8 NA 150 mm Thickness
3 Column Green Circles Quad 8 12 1500 mm Diameter 4 Shear Core Green Plates Beam 2 2 400 mm Thickness
5Beams Connecting the Thick and Thin Slabs Pink Bands Beam 2 1
Depth: 500 mmWidth: 550 mm
6Beams Along the Radius of the Ellipsis Green Bands Beam 2 9
Depth: 350 mmWidth: 1800 mm
7Beams Along the Inner Contour of the Floor Plan Dark Blue Bands Beam 2 1
Depth: 600 mmWidth: 1300 mm
8Beam Along the Outer Contour of the floor Plan Light Blue Bands Beam 2 1
Depth: 600 mmWidth: 1500 mm
Load caseCombination
LoadCase 1
Combination Load
Case 2
Combination Load
Case 3 (Factor)
Combination LoadCase4 (Factor)
Live Load 0.3 0.3 0.3 0.3Dead Load 1 1 1 1Earthquake (X direction)
1 1 0.3 0.3
Earthquake (Y direction)
0.3 -0.3 1 -1
Different Load Cases Considered
Analyses Natural Frequency Solver
Determine Frequencies and modal shapes Spectral Response Analysis Solver
Spectral Response Curve (with S.F.)
Equivalent Static Linear Analysis
1 Bligh Sydney belongs to EDC III, linear static analysis is not required for the earthquake analysis. However it is still carried out to compare with the results from Spectral Response Solver to obtain more insight and reliable results.
Maximum Stress in all 4 Load Cases
Summary of Results in Different Analyses
Mode Frequency(Hz)
Mode
Frequency(Hz)
Mode
Frequency(Hz)
Mode
Frequency(Hz)
1 0.2726 6 1.994 11 2.868 16 3.1152 0.2816 7 2.290 12 2.918 17 3.1613 0.6628 8 2.396 13 2.981 18 3.1644 1.075 9 2.589 14 3.006 19 3.179755 1.317 10 2.650 15 3.110 20 3.17976
Deflection Under Combined Load
Part of Building
The Worst Linear Combination Cases
Tensile/Compressive
Maximum Stress (MPa)
Direction (Global)
ColumnCase 4 Tensile Stress 5.29 ZZ
Case 3Compressive
Stress -24.4 ZZ
BeamCase 1 Tensile Stress 18.7 NA
Case 1Compressive
Stress -18.7 NA
Shear Core
Case 4 Tensile Stress 17.3 ZZ (+z surface)
Case 1Compressive
Stress -29.8 ZZ (-z surface)
SlabCase 2 Tensile Stress 27.5 YY (-z surface)
Case 4Compressive
Stress -27.8 YY (+z surface)
Analysis Method
Max Deflections in
Beams D(XYZ) (mm)
Max Deflections
of Plates D(XYZ)(mm)
Max Fibre Stress of Beams (MPa)
Max Fibre Stress of Plates (MPa)
SRSS 28.6 28.7 2.45 4.78CQC 28.5 28.6 2.39 4.85ESA 36.3 36.4 2.2 3.45
%Difference between SRSS and CQC -0.35% -0.35% -2.45% 1.46%
%Difference between SRSS and ESA 26.92% 26.83% -10.20% -50.00%
Reference:1) Joint Standards Australia/Standards New Zealand Committee BD-006 (2007)AS1170.4-2007 Earthquake Actions in Australia, Second Edition, GPO Box 476, Sydney, NSW 2001, Australia: Standards Australia. 2) Strand7 Webnotes (2013) ST7-1.10.20.9 Spectral Response Analysis , Available at:www.strand7.com (Accessed: 31-May-2013 ). 3) Strand7 Webnotes (2013) ST7-1.10.20.10 Modal Mass, Stiffness and the Mass Participation Factor , Available at:www.strand7.com (Accessed: 31-May-2013 ). 4) Strand7 Webnotes (2013) ST7-1.40.35.22 AS1170.4-2007 Earthquake Analysis in Strand7 , Available at:www.strand7.com (Accessed: 31-May-2013 ). 5) Strand7 Webnotes (2013) ST7-1.10.20.6 Natural Frequency Analysis with loading, Available at:www.strand7.com (Accessed: 31-May-2013 ).
6) Strand7 Webnotes (2013) ST7-1.10.20.9 Spectral Response Analysis , Available at:www.strand7.com (Accessed: 31-May-2013 ). 7) Joint Standards Australia/Standards New Zealand Committee BD-002 (2009)AS3600-2009 Concrete Structures, Second Edition edn., GPO Box 476, Sydney, NSW 2001, 8) Australia: Standards Australia. 9) Hancock, G., Clarke, M., & Wilkinson, T. (2006). Steel Structures 1: Lecture Notes. Sydney: School of Civil Engineering, The University of Sydney. 10) Natural Frequency Solver. (n.d.). Retrieved May 31, 2013, from Strand7: http://www.strand7.com/html/naturalfrequency.htm 11) Spectral Response Solver . (n.d.). Retrieved May 31, 2013, from Strand7: http://www.strand7.com/html/spectralresponse.htm
