PART III
SOLUTIONS FOR CONSTRUCTION TECHNIQUES AND
TECHNOLOGY
III.1 STRUCTURAL SOLUTION
1.0 General
The Artisan Kiosks are located on three isles that cradle themselves against the green parkland at the south eastern part of the Yen So Park Development (Riverwalk). They are isolated by an internal river, and loosely aligned back to back in random dual rows facing the western green park, Yen So lake, and the festive retails.
The building and structures shall be designed and constructed to ensure the structural integrity and serviceability satisfies the requirement of durability, cost effective and aesthetics. Design limiting requirement specified for works of other discipline shall be adopted if they are more stringent than that specified herein. 1.1 Fire Rating
The structural member size, cover, other design details and requirements shall comply with the minimum fire rating requirements as specified in the relevant building by-laws and government agencies.
The minimum fire rating requirement for reinforced concrete shall be 1 hour which is inherent from the nominal cover to the reinforcement.
1.2 Design Load 1.2.1 General
The following loads and forces shall be considered in the structural design:- Dead Load
Imposed Load Wind Load Equipment Load Earth Pressure
Water Pressure including Ground Water Table Seismic Load
If other loads are expected, the following loads shall be included into the design
1.2.2 Dead Load
Dead load shall include the load due to the weight of all walls, permanent partitions, floors, roofs, finishes and all other permanent construction including services of a permanent nature.
Density of Concrete =24 kN / m3
Density of Steel =77 kN / m3
Density of Fill =19 kN / m3
Density of Saturated Fill =9 kN / m3
Density of Gravel =18 kN / m3
Density of Brick Wall =20 kN / m3
Density of Tiles =28 kN / m3
Density of Marble =26 kN / m3
Density of Glass =27 kN / m3
Density of Cement Mortar = 23 kN / m3
Density of Timber =10 kN / m3
Density of Water =9.81 kN / m3
Density of Sewage =9.81 kN / m3
Density of Sludge =12.0 kN / m3
Unless otherwise specified, the superimposed dead load to be used for the detailed design of reinforced concrete floor structures shall be as follows :-Floor Finishes (50 mm thick) = 1.0 kN/m2
Ceiling and Services = 0.5 kN/m2
Lightweight Partition* = 1.5 kN/m2 (allowance only)
* Lightweight partition does not include brick wall or block work which shall be considered separately.
1.2.3 Imposed Load
Imposed load shall include the load produced by the intended occupancy or use, including the weight of movable partitions, distributed, concentrated, impact and inertia, loads, but excluding wind loads
Unless otherwise specially stated, minimum imposed load for structures shall be as follows:-Example of Specific Use Uniformly Distributed Load kN/m2 Concentrated Load kN
Flat Roof (Accessible) 1.5 2.0
Flat Roof (Inaccessible) 0.3 1.5
Office for General Use 2.0 2.7
Toilets 2.0
-Mechanical & Electrical Rooms, Fan Rooms and
the like
7.5 or the actual load,
whichever is greater 4.5*
Storage Floor
2.4 for each metre of storage height or 7.5, whichever is greater 7.0* Office with Computing, Data Processing and similar equipment 3.5 4.5*
Shop Floors for the Sale and Display of
Merchandise
4.0 3.6*
1.2.4 Wind Load
Wind load means all loads due to the effect of wind pressure or suction. Wind load shall be calculated in accordance with BS 6399 : Part 2 with the following
provisions:- Basic Wind Speed V = 50 m/sec minimum
Dynamic Augmentation Factor Cr = 0.25
Size Effective Factor
Ca = 1.0 (Figure 4, BS 6399 : Part 2)
1.2.5 Equipment Load
Equipment load is the load due to the total weight of equipment, special equipment, conveyors, pumps valves, screens pipe work etc. including appurtenances and internals attached thereto or supported thereby.
Where applicable, equipment load arising from erection, testing and normal operation shall be considered together with any vibration caused by the equipment.
1.2.6 Earth Pressure
Earth Pressure means the horizontal pressure of the soil acting on the underground structure and foundation.
Earth pressure shall be calculated from the following equation:- Above Ground Water
P = 0.5 (yh + q) Below Ground Water
P = 0.5[H1 + q + y1 (h - H1)] Where,
P = Earth pressure per unit area at the depth from ground surface (kN/m3)
q = Surcharge load on ground surface (minimum 10.0 kN/m3) H1 = Depth from ground surface to ground water surface (m) Y1 = Submerged soil density (kN/m3)
1.2.7 Water Pressure
Where applicable, buoyancy and lateral pressure due to ground water shall be considered acting on the underground structure of foundation.
Factor of safety of not less than 1.1 shall be adopted in the design to resist uplift pressure during construction and in service as per BS 8007 recommendation.
Consideration must be given to any fluctuation of ground water level and its effect on structures must be assessed for the worse combination of loadings. Actual groundwater levels will be verified by site investigation and monitoring. If the groundwater levels so determined are different from values given above, then the more stringent values should be adopted. In no case should the design head of groundwater be less than that recommended in BS 8102 (Code of practice for protection of structures against water from the ground)
1.2.8 Seismic Load
Building structures shall be checked to resist the lateral seismic forces according to Eurocode 8 with the following Response Spectrum Function Definition:
Design Ground Acceleration, Ag = 0.2g
Subsoil Class = B
Damping Correction Factor, n= 1.0 Response Spectrum Case Data: Spectrum Case
i. Case 1 : x-Direction ii. Case 2 : Y-Direction
Structural and Functional Damping = 0.05(5%)
Modal Combination Method = CQC (Complete Quadratic Combination) Directional Combination = SRSS (Square Root of the Sum of Their Square)
Input Response Spectra = 10% to 12% Vertical Service Load Eccentricity Ratio = 0
1.3 Load Combination 1.3.1 General
All structures shall be designed for the worst combination of loadings with due allowance being made for dynamic loads and all future extensions and additional loads, if any. All loads mentioned shall be combined in the most unfavourable way for design of structural member and stability check of the whole structure
1.3.2 Ultimate Limit State Design
For ultimate limit state design, the design load factors for various load a combination as per BS 8110 shall be as
follows:-Load Combinati
on
Load Type
Dead Imposed Earth
and Water Press ure Win d Seis mic Acciden tal Impact Adver se Benefi cial Adver se Benefi cial Dead and Imposed (and earth and water pressure) 1.4 1.0 1.6 0 1.4 - - -Dead and Wind (and earth and water pressure) 1.4 1.0 - - 1.4 1.4 - -Dead and Imposed and Wind (and earth and water pressure) 1.2 1.2 1.2 1.2 1.2 1.2 - -Dead and Imposed and Accidental Impact (and earth and water pressure) 1.2 1.2 1.2 1.2 1.2 - 1.2 1.2
1.3.3 Allowable Deflections
The allowable deflections under serviceability limit state shall be determined in accordance with the nature of the design and recommendations of the relevant Codes of Practice and Standards.
1.4 Standards and Code of Practice
The following Codes of Practice and Standards shall be
applicable:-a) BS 4449 : 1997 : Carbon Steel Bars for the Reinforcement of Concrete b) BS 6399 : Part 1 : 1996 : Code of Practice for Dead and Imposed Loads c) BS 6399 : Part 2 : 1997 : Code of Practice for Wind Loads
d) TCVN 2737 : 1995 : Loads and Actions – Design Code e) BS 8110 : Part 1 : 1997 : Structural Use of Concrete
f) BS 8007 : 1987 : Design of Concrete Structures for Retaining Aqueous Liquids.
g) BS 5950 : Structural Use of Steelwork in Building
h) Eurocode 8 : Design Structures foe Earthquake Resistance.
All reinforced concrete structures shall be designed in accordance with BS 8110 except for watertight concrete structures which shall be designed to BS 8007. All steel structures shall be designed in accordance with BS 5950.
1.5 Structural Analysis and Design Software
The following software will be used for structural analysis, design, and draughting purposes:- EsteemPlus 6.6.1.3 CSC Orion R15 STAAD Pro 2004 AutoCAD R14 / 2007 LT JPT Calculation Spreadsheet
1.6 Building Structure
The complete building structure can be broken down into following elements:- Beams
Slabs Columns Walls
Bases and Foundations 1.6.1 Bases and Foundations
Bases and foundations are pads or strips supported directly on the ground that spread the loads from columns or walls so that they can be supported by ground without excessive settlement. Alternatively, the base maybe supported by piles. The bases and foundations are designed as reinforced concrete foundation to BS 8110.
1.6.2 Main Structure
The structure system of buildings is reinforced concrete frame structure consists of beams, slabs, columns and walls. Beams are horizontal members carrying lateral loads; slabs are horizontal plate elements carrying lateral loads; columns are vertical members carrying primarily axial load but generally subjected to axial load and moment; walls are vertical plate elements resisting vertical, lateral or in-plane loads. All elements are designed as reinforced concrete elements to BS 8110.
1.7 Construction Materials
All structural materials incorporated in the works shall comply with relevant Standards and Code of Practice. The concrete for reinforced concrete structures including buildings and shelters shall be Grade 30/20, Grade 35/20 or higher. Grade 43A shall be used for structural steel. All RC structures / tanks containing sewerage shall be designed to minimum Class 2 sulphate conditions as defined in BS 8110. Internal epoxy lining to RC tanks containing sewerage shall be provided especially at the design top water level.
The characteristic strength of other materials specified in the applicable Code of Practice given above shall apply to all designs.
Strength of steel
reinforcement:-Hot rolled mild steel 250 N/mm2
High yield steel (Hot rolled and cold worked) 460 N/mm2
