2018 12 03 design brief for db rev 0

1 1 Introduction of the Design Brief This Design Brief prepared by Tham&Wong T&W summarizes some main ideas of the structural design which gives an option for the structure of the proje

STRUCTURAL DESIGN BRIEF FOR DESIGN & BUILD PACKAGE

Client: CapitaLand (Vietnam)

Project: SUNNY

Address: Ung Van Khiem road, Ward 25, Binh Thanh

District, Ho Chi Minh city, Vietnam

Issue date: December 03, 2018

Revision: R0

STRUCTURAL DESIGN BRIEF FOR DESIGN & BUILD PACKAGE

Client: CapitaLand (Vietnam)

Project: SUNNY

Address: Ung Van Khiem road, Ward 25, Binh Thanh

District, Ho Chi Minh city, Vietnam

Director

Ir LIM CHIN KEONG

Table of Contents

1 Introduction of the Design Brief 1

2 Project information 1

2.1 Building functions 2

2.2 Basis documents 2

3 Codes and standards 2

4 Major design criteria 3

4.1 Design reference period 3

4.2 Fire Resistance 3

4.3 Building class 3

5 Materials 3

5.1 Concrete 3

5.2 Reinforcement 5

5.3 Structural steel 6

6 Design loads 6

6.1 Dead load 6

6.2 Live load 8

6.3 Seismic action 8

6.4 Wind load 9

6.5 Structural design method and analysis 10

6.6 Design method 10

6.7 Analysis 10

7 Load combination 11

8 Serviceability limits 13

8.1 Settlement 13

8.2 Lateral deflection 13

8.3 Deformation of structural components 13

8.4 Acceleration criteria 14

9 Structural system 14

9.1 Foundation system approach 14

9.2 Superstructures 15

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1 Introduction of the Design Brief

This Design Brief prepared by Tham&Wong (T&W) summarizes some main ideas of the structural design which gives an option for the structure of the project This design brief is intended to supplement the information and minimum requirement for Design & Build (D&B) works Unless otherwise specified herein, the design work shall be executed in accordance with the requirements and recommendations

of the Vietnam Standards (TCVN) that are current at the date of the tender and the requirements in this

Design Brief and The Specifications for Construction Works Where there is conflict, the more severe

requirement of either the Vietnam Standards or this specification shall take precedence

2 Project information

- Project name: SUNNY;

- Location: Ung Van Khiem road, Ward 25, Binh Thanh district, Ho Chi Minh city;

Figure 1 Site location

Figure 2 Rendering perspective of the project 2.1 Building functions

- Basement: B2 – B1 Car parking + MEP devices + water tanks

- Towers: Luxe tower: Residential

Mixed tower: Residential Commercial tower: Office 2.2 Basis documents

- Architectural design documents

- Mechanical design documents

- Geological site investigation report

- Wind tunnel test report

3 Codes and standards

The structural design complies with all the relevant Vietnam Technical Regulations and following standards:

- QCVN 03:2012/BXD National Technical Regulation on Rules of Classifications and Grading of Civil and Industrial Buildings and Urban Infrastructures

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- QCVN 06:2010/BXD Vietnam Building Codes on Fire Safety of Buildings and Structures

- ISO 10137:2007 Bases for design of structures - Serviceability of buildings and walkways against vibrations

- TCVN 2737:1995: Loads and actions – Design standard

- QCVN 02:2009/BXD: Vietnam Building Codes, Natural physical & Climatic data for construction

- TCVN 9386:2012: Design of structure for earthquake resistance – Part 1 and Part 2

- TCVN 10304:2014: Pile foundation – Design standard

- TCVN 9362:2012: Specifications for design of foundation for buildings and structures

- TCVN 5574:2012: Concrete and reinforced concrete structures – Design standard

- BS EN 1992-1-1:2004: Eurocode 2: Design of concrete structures – Part 1-1: General rules and rules for buildings

- BS EN 1992-3:2006: Eurocode 2: Design of concrete structures – Part 3: Liquid retaining and containment structures

- BS EN 1990:2002 Eurocode - Basis of structural design

- BS EN 1993-1:2005: Eurocode 3: Design of steel structures – Part 1: General rules and rules for buildings

- BS EN 1994-1-1: 2004: Eurocode 4: Design of composite steel and concrete structures Part 1-1: General rules and rules for buildings

4 Major design criteria

4.1 Design reference period

The design reference period of this building is 100 years

4.2 Fire Resistance

Fire resistance for structural elements complies with QCVN 03-2012 The project is classified as Fire

Resistance Class I, for which fire resistance of the main structures is R180, of slab is REI 90 (Clause 2.2.2.1.3)

4.3 Building class

The towers, regarding to TCVN 9386:2012, is classified as “Grade I”

5 Materials

5.1 Concrete

The concretes used in the design of this project comprise of the grades as given in It is noted that the grade of used concrete may be different for towers

Table 1 It is noted that the grade of used concrete may be different for towers

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Table 1 Concrete grade used in the design

Basement 120 ± 20

Beams, Slab and, Pile cap for

basement 2

Beams, Slab for block A, B, C,

Podium

B35 (M450) Ground Floor to 6th: 120 ± 20

7th to 15th: 140 ± 20

16th to 30th: 160 ± 20

31st to Roof: 180 ± 20: 125 ± 20 Lintels and non-structural

items

B55: Foundation – 20Th

B45: 21st - Roof

Ground Floor to 6th: 120 ± 20

7th to 15th: 140 ± 20

16th to 30th: 160 ± 20

31st to Roof: 180 ± 20

Pre-stressed beam-slab for

block D

5.2 Reinforcement

The steel reinforcement used in the design shall be based on TCVN 1651:2008 or equivalent as shown

in

Table 2

Table 2 Concrete grade used in the design

Deformed bar, type CB-500V or equivalent: to be used for longitudinal rebar of pile

caps and superstructure (beam, column, wall, slab) (Diameter ≥ 10mm)

500

Mild steel bar, type CB-240T or equivalent: Diameter < 10mm 240 5.3 Structural steel

The structural steel use grade S275 and S355 according to BS EN 10025 or equivalent

6 Design loads

6.1 Dead load

Table 3 Dead load

Floor finishes (50mm including screed and tiles, or raised floor system) 1.05

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6.2 Live load

Table 4 Live load

6.3 Seismic action

Seismic action is determined in accordance with QCVN 02:2009/BXD with the reference ground

acceleration at the building site (Binh Thanh district, Ho Chi Minh city) is agR= 0.8299 m/s2, Importance Class is I (building from 20 to 60 stories), thus, important factor is 1.25

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The structure is not torsional flexible, so it is decided to design with medium ductility class (DCM) with

the behavior factor q =2.52 for block B and D, q =3.15 for block A and C to consider the change of

stiffness in vertical direction (adjust coefficient of 0.8)

For the structural element supporting the transfer column or transfer beam, the behavior factor q = 1.5

will be adopted

Based on the soil investigation report of project, the average NSPT within the first 30m from the ground level is less than 15, therefore the soil is classified as Type D according to Table 3.1 of TCVN 9386:2012 The design spectrum to be used for seismic analysis will be calculated by the analysis programs ETABS and Midas Gen based on Eurocode 8-2004 with the above input data, using response spectrum Type

1, which is applicable to Vietnam according to TCVN 9386:2012

6.4 Wind load

6.4.1 Wind load determined by code analytical provisions

Forces due to wind load will be calculated based on basic wind speed of the location of the proposed building, which is given in QCVN 02:2009/BXD for Binh Thanh district of Ho Chi Minh city as zone II.A with basic wind speed for designing with Eurocode is Vo = 28.57 m/s According to QCVN 03:2012 this building shall be designed with service life of 100 years; thus, the wind load shall be proportioned accordingly with probability factor given in Eurocode 1 The building is close to the river therefore the terrain shall be type II

6.4.2 Wind load determined by wind tunnel method

Wind tunnels are widely used to reliably predict the wind loading on the cladding and glazing as well as

on the structural frames of tall buildings In this building, a wind tunnel test was done in parallel with the determination by code in order to obtain more accurate load for design Wind tunnel test helps to reliably estimate the wind load acted on the networking floors which its shape is not covered by standard provisions Furthermore, reference from design of some high-rise projects shows that the wind load determined by test is 20-30% smaller than that got by code analytical provisions As a result, the structural cost might be reduced

A report of wind tunnel test prepared by Wacker is included in this pack for the D&B tenderer’s reference The D&B tenderer will take the responsibility to check and re-analysis the result of the wind tunnel test

if any The cost for the test shall be coved in the tender cost

6.5 Structural design method and analysis

6.6 Design method

6.6.1 Ultimate limit state

Two limit states used as design methods are Ultimate Limit State (ULS) and Serviceability Limit State (SLS) The usual approach is to design on the most critical limit state and then check that the remaining limit states will not be reached The structures shall generally be designed in ultimate limit state which

is the most critical state

Analysis and design of normal PT and RC structures (slabs, beams, columns, walls) shall be done based

on Eurocode 2 Composite structures columns will be designed according to Eurocode 4

6.6.2 Serviceability limit state

The SLS is used to check the deflection and cracking of structures Deflection of structures must be satisfied criterial listed in Section 8 while cracking is generally satisfied the rules in the BS EN 1992 standard for post tensioned beam and TCVN 5574:2012 for normal RC beam slab system

6.7 Analysis

6.7.1 General

The analysis that is carried out to justify a design can be broken down into two stages as:

- Analysis of the overall structure

- Analysis of members

In the analysis of the overall structures, or part of overall structure, to determine force distributions within the structure, the properties of materials may be assumed to be those associated with their characteristic’s strength, irrespective of which limit state is being considered

In the analysis of any cross-section of members within the structure, the properties of materials should

be assumed to be those associated with their design strengths appropriate to the ultimate limit state being considered (ULS)

6.7.2 Analysis of the structure

Linear elastic behavior shall be applied in the analysis of the overall structures Relative stiffness of members shall be based on the entire concrete cross-section, ignoring the reinforcement Redistribution

of force and moments is acceptable up to maximum of 10% Seismic analysis will follow the provision for cracked section as given in TCVN 9386:2012

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6.7.3 Analysis of members

Characteristic strengths of concrete, reinforcement and structural steel are given Section 4 Further detailed analysis of concrete sections is referred to corresponding standards (BS EN 1992, BS EN 1993,

BS EN 1994, TCVN 5574:2012)

7 Load combination

The load combinations used in the design for RC structures are listed in Table 5

Table 5 Load combination Load combination for ultimate limit stage:

Load combination for beam and slab deflection and crack checking:

Combination DL SDL BW LL LLA LLR Wx Wy Ex Ey

Load combination for piling design:

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In which:

- DL is the dead load;

- SDL is the super dead load

- BW is wall load

- LL, LLA, LLR are live load, live load less than or equal 1.5 kN/m2, and live load in Podium, respectively

- Wx, Wy are the wind load in X and Y direction

- Ex and Ey are the seismic effect in X and Y direction, which have considered both modal combination with CQC method and directional combination with SRSS method

8 Serviceability limits

8.1 Settlement

The settlement limit is complied with TCVN 10304:2014

8.2 Lateral deflection

Overall deflection (Wind load) ≤ Height/500

Story Drift (Seismic) ≤ Story height/80

8.3 Deformation of structural components

Total deflection ≤ Span/250

Imposed load deflection ≤ Span/360

8.4 Acceleration criteria

To ensure the comfort of residents from a vibration caused by wind load, a peak acceleration limits of the building are considered This peak limits can be determined by a structural analysis or the result of wind tunnel study The total response of lateral acceleration (the peak combined effect of the along-wind, across-along-wind, and torsional loads) at the structural top level shall comply with the requirements from EN 1990:2002, EN 1991-1-4:2005 and ISO 10137:2007 The peak acceleration at the top floor shall not exceed the basic curves given in Appendix D of ISO 10137:2007 as shown in Figure 3

Figure 3 Acceleration criterial by ISO 10137:2007

9 Structural system

9.1 Foundation system approach

Bored piles are intended to use for towers In the proposed design, T&W used the bored piles with diameter of 1000 mm, 1200mm and 1500 mm Diaphragm wall with thickness of 800~1000mm was proposed because the project includes two basements

The contractor can consider using bored piles with shaft-grouting in order to reduce the depth of piles and/or to increase the supporting capacity Design of shaft-grouting bored piles was not presented in the T&W’s proposal

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9.2 Superstructures

For Residential towers, the structure of shear-wall, flat slab with perimeter is designed For Commercial tower, the structure of columns, core wall, and pre-stressed beam-slab is intended to use as the large span of beam-slab

Belt outriggers are introduced in Luxe tower for increasing the transversal stiffness of the tower