Civil- Structural Dbr

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CIVIL - STRUCTURAL DESIGN BASIS REPORT (DBR)

DOCUMENT TITLE:

CIVIL STRUCTURAL DESIGN BASIS REPORT

Pages modified under this revision: STRUCTURAL - DBR

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CONTENTS 1. INTRODUCTION....................................................................................................................... ...................................................................................................................................................................... ...............................................2 2. SITE LOCA LOCATION TION........................................................................................................... .................................................................................................................................................................... ......................................................... ..3 3. DEFINATIONS ..........................................................................................................................................................................................................3 4. FACILITIES PLANNED............................................................................................................ ........................................................................................................................................... ............................... ......... ......3 5. DESIGN UNITS .................................................................................................................................................................... .................................................................................................................................................................... ....3 6. SOIL & EARTHWORKS .........................................................................................................................................................3 7. BUILDING STRUCTURAL COMPONENTS................................................................................................................. ......4

7.1 PLANT building.............................................................................................................. ............................................................................................................................................................... ................................................. ..... 4 7.2 WAREHOUSES............................................................................................................. ....................................................................................................................................................... .......................................... ........ ............. ..... 5 7.3 UTILITY BLOCKS.................................................................................................................... ............................................................................................................................................................... ........................................... 6 7.4 ANCILLARY BLOCKS....................................................................................................................... ...................................................................................................................................................... ............................... .. 7 7.5 CLADDING......................................................................................................... ................................................................................................................................................................ ....................................................... ........ .......... .. 7 7.6 FLOORING........................................................................................................... ......................................................................................................................................................................... .............................................................. .. 7 7.7 INFRASTRUCTURE WORKS................................................................................................................................... ........ .......... 7 7.8 WATER STORAGE SYSTEMS............................................................................................................ ............................................................................................................................................ ................................ 8 8. GENERAL DESIGN PHILOSOPHY.................................................................................................... ................................................................................................................................. ............................. .....8

8.1 architectural development plan....................................................................................................................... .............................................................................................................................................. ....................... 8 8.2 development phases.......................................................................................................... ............................................................................................................................................................... ..................................................... 8 8.3 PEB Roof..................................................................................................................... ............................................................................................................................................................................... .......................................................... 8 8.4 RCC Structure ....................................................................................................................................................................... 9 9. MA MATERIALS TERIALS SPECIFICATIONS SPECIFICATIONS – ............................................................................................................... ................................................................................................................................... .................... ....9

9.1 pRE-ENGINEERED BUILDING material specifications.................................................................................................... 9 9.2 CONCRETE material specifications.................................................................................................................. .............................................................................................................................. ................. ..... 10 10. DESIGN PARAMETERS.................................................................................................... ...................................................................................................................................................... ..................................................11 11

10.1 peb works............................................................................................................... ........................................................................................................................................................................... ............................................................ 11 10.2 concrete works........................................................................................................... ................................................................................................................................................................... ........................................................ 15

1.

INTRODUCTION

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2.

SITE LOCATION

3.

DEFINATIONS

4.

FACILITIES PLANNED

5.

6.

DESIGN UNITS The International (SI) system of metric units is used for this project. SOIL & EARTHWORKS Soil investigation carried out in the proposed site recommends adopting SBC and other design criteria’s as follows: SBC of Soil (for all the buildings) SBC of Soil for Boiler house area Water Table soil

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: : :

2.50 kg/cm² 3.00 kg/cm² NA, as was not encountered as per report

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Depth of Foundation

:

1.5 m below finished ground level

Type of Foundation

:

Isolated / combined foundation

Settlement criteria soil report

:

Within Permissible Limits, as per

BUILDING STRUCTURAL COMPONENTS Primarily, the building structural components have been subdivided as per the following.

7.

•

PEB Roofing System

•

Cladding / Solid block masonry wall

•

Concrete Flooring

•

RCC framed structure

By considering the functionality of the buildings, various combinations of roofing systems have been evaluated as per the following. PLANT BUILDING

7.1

In the Plant Building, the grid of 7.5m x 13.75m has been considered as per the internal machinery layout of the ground floor. The Plant Building shall have mezzanine slab at +10.60 m level which will act as a machine floor. The machinery loading on this floor has been considered as 750 Kg/m² based on the requirement for the floors of plant building as per the codal provisions. It is envisaged that there will be vibrations from the machinery which needs to be isolated from the rest of the structure. It is planned to isolate the supporting of the machinery from the main building which requires a separate structural support for mounting of the machines. By doing this, vibrations will not be transferred to the main building. However the machines in particular, the vibratory conveyors will give rise to vibration levels that will cause some level of discomfort to human beings and may adversely affect the functioning of sensitive electronic gadgets attached to these machinery. To address these problems, these machines have to be designed and fabricated such that proper load balancing is done. Further these machines have to be provided with suitable spring supports which will act as energy dissipating devices. The first floor of the plant building will have sloping roof with the pitch of 1 in 10 with bare galvalume sheet roofing and it is designed for a load intensity of 75 kg/m² and service load of 35kg/m² with stainless steel gutters on either side. Following structural systems have been considered for evaluation: Ground Floor Structural System: •

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RCC Beam Slab Structure:

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•


Grid slab

First Floor Structural System: •

PEB rafters with sheet roofing

•

RCC Beam at Gable end

RCC Beam Slab Structure: •

Column Grid: 7.5m x 13.75m

•

Beam Grid: 3.75m x 13.75m

•

Beam Sizes: 450mm x 1200mm

•

Slab Thickness: 175mm

•

One way slab system

•

Ease of construction

•

Relatively more number of corners for dust collection. To mitigate this, chamfering/coving has been planned for all the junctions for easy clean ability

•

Ease of flexibility in machinery layouts

•

Ease of vibration separation for the machineries

•

The possibilities of beetle infestation is very low

•

Economical

PEB rafter & purlins with sheet roofing: •

•

7.2

Column Grid: 7.5m x 27.5m Supporting System: PEB rafter with fixed base supported on RCC Columns at 19.85m (top of concrete of Column)

•

Flashings at the eaves and at the gables

•

Ease of construction

•

Flexibility in supporting the services from the roof

•

Relatively economical

•

Speed of construction

WAREHOUSES

The grid for the warehouses has been adopted based on the type of roof supporting system that will be adopted for evaluation purpose. The eaves

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height of the warehouse has been considered as 6.00m based on the Fire and Line Safety norms so that no extra treatment for the structure will be required to meet these standards. The ware house roofing has been envisaged as sloping roof with a design load intensity of 75 kg/m² together with a service load of 25kg/m² with the pitch of the roofing as 1 in 10. RCC Columns are being planned up to the eaves height for all the systems, RCC Gutters/MS Gutters have been considered depending upon the type of roofing system. Following structural systems have been considered for evaluation: •

PEB rafters with sheet roofing

•

RCC Beam at Gable end

•

RCC framed structure supporting PEB rafters with PEB stool.

By evaluating the above systems, the roofing system for the warehouses has been adopted as Pre Engineered Building Roofing system with bare Galvalume sheet roofing. Salient features of the same are presented below. •

•

PEB - MS Gutters at the ends. RCC gutters intermediate gutters in the case of two span building

•

PEB rafter with PEB stool of 0.75m height and Purlins

•

Bare galvalume sheet roofing with self tapping screws fixing

•

Flashings at the eaves and at the gables with foam fillers to fill the corrugation gaps

•

All the fabrication is factory made.

•

Speed in execution

•

7.3

Column Grid: 7.5m x 27.5m

Quality maintenance is easy as entire fabrication will be done in the factories in a controlled environment

•

Flexibility in supporting the services from the roof

•

Relatively economical

UTILITY BLOCKS

These blocks are mainly to house the various utilities required for the process such as Power House, Boiler House and Crusher etc. as per the list given in the introduction. The roofing for these blocks will be as per the following. •

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Engineering Stores: The roofing will be the Pre Engineered Building Roofing System with bare galvalume sheet roofing. The roofing system for this is in line with the ware house roofing system.

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•

•

•

7.4


Power House: The roofing will be Reinforced Cement Concrete slab with 5.00mtrs head room for the panel room. This is principally to locate the cooling towers on the top of the slab. The loading is to be considered as 500 Kg/m² as per the loading requirements. The D G room will have Pre Engineered Building sheet roofing with a head room of 8mts. Coal Yard: The roofing form will be Pre Engineered building sheet roofing system to economize the cost of the structure with the eaves height of 7.8m. Boiler House and Crusher: The roofing form will be the Pre Engineered Building roofing system with louvered cladding for the Boiler House.

ANCILLARY BLOCKS

The roofing system for all these buildings has been considered as Reinforced Cement Concrete slab with 4.50mts as soffit of the slab. This is primarily to account for the vertical expandability of the buildings. Hence foundations and columns for all these buildings are being designed for one extra floor. 7.5

CLADDING

The cladding for all the buildings has been considered as 200mm thick solid block masonry with 12mm thick smooth cement plastering for inside and 18mm thick sand exposed cement plastering for outside. This is primarily due to the following reasons.

1

7.6

•

To have a clean surface from inside to avoid dust collection

•

To satisfy the EHS Norms

FLOORING

It is proposed to have reinforced 150mm thick Vacuum Dewatered Concrete flooring of Grade M25 for the Plant Building, Warehouses and for the Utility Blocks by considering the following requirements into consideration. •

To have smooth, impervious and non slippery flooring

•

To take care of fork lift movement

•

To take care of point loads of the racking system

•

To minimize the dust generation from the floor

•

To minimize the shrinkage cracks

In addition, it is proposed to have non metallic floor hardener topping for the floors of Plant and Warehouses to protect the flooring from normal wear and tear. It is proposed to have vitrified tile flooring/granite flooring for the amenities blocks. 7.7

INFRASTRUCTURE WORKS

It is proposed to have black topping roads for the material movement roads to take care of 40 Ton truck load and to have grass pavers roads for fire tender

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movement. And also, it is proposed to have complete storm water drainage system with random rubble masonry construction to optimize the cost of construction. WATER STORAGE SYSTEMS

7.8

It is proposed to have above ground storage systems for raw water, fire water and soft water tanks along with the pump room to house all the pumps and other equipments. The constructions of these tanks are to be of reinforced cement concrete construction with ceramic tile lining for internal finish of the walls. It is proposed to have overhead tank of 100.00 cum capacity at 30.00 m height as per the requirement of water head. The proposed construction is of reinforced cement concrete columns up to 30.00 m height and is to have reinforced cement concrete walls with ceramic tile lining for internal finish of the walls. 8.

GENERAL DESIGN PHILOSOPHY The designed life of the building is assumed as 50 years. 8.1

ARCHITECTURAL DEVELOPMENT PLAN

The design of the buildings, plant enclosures and exposed plant shall be such as to produce a co-ordinated architectural scheme, aesthetically pleasing, compatible with and visually related to the surroundings. It shall also minimize regular and long term maintenance, by the selection of materials and finishes appropriate to this objective. The layout of buildings and roads shall allow for easy circulation and access for maintenance purposes. Allowance has to be made in the site layout and the arrangement of the buildings and the machines therein for the future possibility of an extension to the buildings to accommodate further sets of a similar size. Full consideration shall be given to natural light & ventilation at the building design stage. 8.2

DEVELOPMENT PHASES

It is envisaged that the development shall take place in 3 phases, presently the work commence with phase I. 8.3

PEB ROOF

The roof comprises of a rafter seated over a stool above the RCC columns. The scope of the work of Pre engineered building roofing system shall be design, engineering, manufacture, protective packaging, supply, erection, performance testing and handing over of Pre engineered building roofing system and accessories as per building descriptions, technical specifications and drawings. The PEB rafters shall be checked with all possible loads and load combinations which can occur during the entire life span of the structure.

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RCC STRUCTURE

8.4

The structure below the roof shall comprise of RCC Footings Columns and tie beams. The structural frames of the building below roof shall be designed with the reaction from the roofing system provide by the PEB vendors, along with the loads which act over the framing system. The RCC frames shall be checked with all possible loads and load combinations which can occur during the entire life span of the structure. Also the buildings are designed to be fire resistant with a fire rating of 3 hours. The columns shall be designed for a full length to be independent of the tie beams below 5.0 m level from the FFL or Floor Slab Level, as the width of the beams at this level shall be restricted to 200mm to flush the wall thickness, for the following reasons listed below, •

Functional requirement on the inside of the building

•

Aesthetic requirement on the outside of building To avoid the frequent maintenance requirement and the problem of dust accumulation.

•

MATERIALS SPECIFICATIONS –

9. 9.1

PRE-ENGINEERED BUILDING MATERIAL SPECIFICATIONS

The following is the list of the material standards and specifications for which the building components shall be designed:

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MATERIAL

SPECIFICATION

STRENGTH

Plates for Built-up

ASTM A572 M

Fy = 34.5 kN/cm2

Hot Rolled Sections Coils for Cold Formed (Pre-Galvanized)

ASTM A53 M

Fy = 24.0 kN/cm2

ASTM A653 M G90

Fy = 34.5 kN/cm2

ASTM A792 M

Fy = 55.0 kN/cm2

ASTM A36

Fu = 40.0 kN/cm2

ASTM A36

Fu = 40.0 kN/cm2

ASTM A325 M

Ft = 30.3 kN/cm2 Fu = 72 to 83 kN/cm2

Machine Bolts

ASTM A307 M

Ft = 13.2 kN/cm2 Fu = 40.0 kN/cm2

Eaves gutter

Std. wall material profiled eaves gutter

NA

Skylite

2.0mm thk. Polycarbonate

NA

EXTERIOR ROOF PANEL X-Bracing (Rods/ Pipes) Anchor Bolts High Strength Bolts

CONCRETE MATERIAL SPECIFICATIONS

9.2

Cement: 43 Grade ordinary Portland cement shall be used conforming to IS 8112. •

Mineral Admixtures: Fly ash conforming to Grade 1 of IS 3812 may be used as part replacement of ordinary Portland cement provided uniform blending with cement is ensured. •

Aggregates: Aggregates shall comply with the requirements of IS 383. Coarse aggregates used shall be 20mm down size graded for nominal concrete. •

Water: water used for mixing and curing shall be clean and free from injurious amount of oils, acids, alkalis, salts, sugar, organic materials or other substances that •

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may


be concrete or steel.

deleterious

to

Admixtures: Admixtures if used shall comply with IS 9103.

•

Reinforcement Steel: High Strength deformed steel bars shall conform to IS 1786. •

DESIGN PARAMETERS The main considerations followed for the designs are:

10.

•

Structural safety and stability.

•

Demands of aesthetics conceived by the architect

•

Availability of material, equipment and expertise

•

Constructability and ease of maintenance

•

Durability and

•

Economy

PEB WORKS

10.1 10.1.1

GENERAL

The buildings mentioned in the ‘facilities planned’ section above, shall be analysed as 2-Dimensional frame structural system. The buildings shall be modelled using STAAD PRO software. The model frame shall be analyzed for dead loads (DL), live loads (LL), wind loads (WL), collateral loads and seismic loads (EQ) and their combinations as per IS: 875 – 1987: Code of Practice for design loads (other than earthquake) for buildings and structures & IS: 1893 (Part 1): Criteria for Earthquake Resistant Design of the structures and structure is to be designed as per the standard practice. 10.1.2

SUPPORT CONDITIONS •

•

•

•

•

•

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The main frame rafters and exterior columns at all grid lines shall be rigidly connected to each other (using moment type connections). Rigid frame external Columns shall be fixed and internal column shall be pinned connected to the foundations. The lateral stability of the building shall be provided through the frame action of the main rigid frames. The longitudinal Force from the Roof shall be transferred to RCC column at braced bay location. The roof purlins shall be continuous beams to be supported at rigid frame locations and span the bay spacing of the building. Purlins shall be provided with minor axis buckling restraint to rafter. Screw down sheeting shall be provided as lateral restraint to girt / purlin flange. For standing seam panel no restraint shall be considered for purlins. If purlin

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/ girt bridging used, same shall be provided with minor axis / compression flange buckling restraint depending upon their implementation. 10.1.3

DEAD LOADS

Dead loads shall cover unit weight/mass of materials, and parts or components in a building that apply to the determination of the dead loads in the design of buildings and shall be considered as per IS: 875 (Part 1) - 1987 according to the densities of the possible components. This includes main frames, purlins, girt, cladding, bracing and connections etc. 10.1.4

IMPOSED LOADS

Imposed loads shall be considered as per IS: 875 (Part 2) – 1987. Live load shall be considered as 0.75 KN/m² for the analysis and design. 10.1.5

COLLATERAL LOADS Collateral Load consist of service loads like piping etc

1

10.1.6

: 0.35 KN/ m²

•

Plant Building

•

GLS, Cooling, RDS : 0.35 KN/ m²

•

Power House

•

Engineering Block : 0.35 KN/ m²

•

Boiler House

: 0.50 KN/ m²

•

Coal yard & Crusher

: 0.35 KN/ m²

: 1.00 KN/ m²

WIND LOADS

The basic wind speed and design velocity which shall be modified shall be taken as per IS: 875 (Part 3) – 1987. The basic wind speed at Mysore shall be considered as 33m/sec. This shall be considered for calculating the wind loads. Analysis shall be carried out by considering future expansions if any which has been indicated in the building descriptions and critical forces shall be taken for design. 10.1.7

SEISMIC LOADS

The proposed structures in this project shall be analyzed for seismic forces. The seismic zone shall be considered as per IS: 1893-2002 (Part 1). For analysis and design, Zone II shall be considered as Mysore region falls under this zone as per IS: 1893-2002 (Part 1). Earthquake analysis shall be carried out using STAAD PRO as per the provisions of IS: 1893-2002 (Part 1) & IS: 1893-2005 (part 4). The analysis parameters shall be taken as per the following. Zone Factor: 0.10 Importance Factor: 1.00

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Response Reduction Factor: 10.1.8

3.00

LOAD COMBINATIONS

Load combinations for member design shall be as follows: •

1.5 ( DL + CL + LL )

•

1.5 ( DL + WL )

•

1.5 ( DL +/- EQ )

•

0.9 DL + 1.5 WL

•

0.9 DL +/- 1.5 EQ

•

1.2 ( DL + CL + LL ) + 0.6 WL

•

1.2 ( DL + CL + LL ) +/- 0.6 EQ

•

1.2 ( DL + CL + LL + WL )

•

1.2 ( DL + CL + LL +/- EQ )

Load combinations for Deflection criteria shall be as follows: •

DL + LL + CL

•

DL + CL + 0.8 LL + 0.8 WL

•

DL + CL + 0.8 LL +/- 0.8 EQ

•

DL + WL

•

DL +/- EQ

An allowance increase in permissible stresses shall be done with Wind/Seismic Combinations as per codal provision. 10.1.9

SERVICEABILITY CHECK

Limitation for vertical deflections: •

Frame Vertical – L/180

•

Purlin Vertical – L/150 for (Live & Wind)

Limitation for Lateral deflections:

10.1.10

•

Wind load deflections – height / 150

•

Earth quake deflections – height/250

ANCHOR BOLT

Bracing reactions shall be considered with the main frame reactions. The installation of the anchor bolts and embedded items must be done in accordance with the code of standard practice for steel building with

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maximum allowable tolerances as per codal provisions. Anchor bolts shall be set perpendicular to the theoretical bearing surface. The gab between steel base plate and RCC column surface shall be filled with a compact non-shrinking grouting material, Conbextra GP2 or equivalent. Anchor bolts shall be fabricated from the rods conforming to ASTM A36 Gr. – 36 or equivalent with minimum yield strength of 235 N/mm². 10.1.11

MAIN FRAME & PRIMARY MEMBERS

All the primary framing members shall be fabricated from plates confirming to ASTM A572 Gr. 50 or equivalent with minimum yield strength of 345 N/mm². Continuous machine submerged arc welding shall meet the applicable requirement of AWS D1-1:2006. Web to flange welds shall be Double Side Fillet Weld. Flange / web butt welds shall be full strength joints using submerged arc welding. 10.1.12

BRACINGS

All bracing rods shall conform to ASTM A36M Gr.36 / IS: 2062 Grade A or equivalent with minimum yield stress 245 N/mm². All secondary Cold formed ‘Z’ and ‘C’ sections shall conform to ASTM A653M 04a, Gr. 65 or equivalent with minimum yield stress 450 N/mm². Galvanizing coating mass shall be 275gms/m². All Flange braces & Purlin bridging sections shall conform to ASTM A 653M 04a, Gr. 50 or equivalent with minimum yield stress 345 N/mm². Galvanizing coating mass shall be 275gms/m². 10.1.13

FASTENERS

Mild steel bolts shall be electro plated to yellow chromate, fully threaded. Mild steel bolts shall not be provided with flat washers. Bolts shall conform to ASTM A307 Grade 4.6 High strength bolts shall be plain galvanized finish fully threaded and shall be identifiable by marks on the head. These bolts shall be provided flat washers. Material shall conform to ASTM A325m Type 1, Grade 8.8. 10.1.14

ROOF SHEETING

MR24 panels if applicable, shall be manufactured from 0.60mm BMT steel conforming to ASTM A792 or AS-1397, with a minimum yield strength of 345 Mpa, coated with hot dip metallic Aluminum-Zinc alloy coating, Zincalume – AZ150 (150 gms/m² total on both sides, Aluminum 55%, Zinc 43.5% and silicon 1.5%) All profiled panels except MR24 panels shall be manufactured from Hi-tensile steel with a minimum yield strength of 550 Mpa, metallic hot dip coated with Aluminum-Zinc alloy (Aluminum 55%, Zinc 43.5% and silicon 1.5%) as per AS1397 Zincalume –AZ150 (150 gms/m² total on both sides). Color coated panels shall have super polyester XRW quality paint coat as per AS/NZS 2728 class-3. Trims and flashings material specification shall be same as above.

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10.2

CONCRETE WORKS

10.2.1

GENERAL

This section covers the standard specifications, criteria and parameters to be followed for the detailed design of concrete work for the structures mentioned above in this document. 10.2.2

AIM OF DESIGN

The aim of design is to achieve the acceptable probability that structure being designed will perform satisfactory during the design span life. With an appropriate degree of safety, the building will sustain all the loads and deformations of normal construction and use and have adequate durability and adequate resistance to the effects of misuse and fire. 10.2.3

METHOD OF DESIGN

This RCC structure and structural elements are designed by Limit State Method. Characteristic loads with appropriate partial safety factors are considered in the design. Besides the strength, to ensure durability of the structure, Concrete Mix M25 is used for foundations, columns and beams with grade of reinforcement steel of Fe 500. Since the building falls under seismic Zone II, for static response of structure under seismic conditions, ductile detailing is not required and hence not adopted in accordance to IS 13920. For water retaining structures Working stress method will be adopted as per IS 3370. 10.2.4

STANDARD SPECIFICATIONS

For all structural concrete shall develop a minimum compressive strength of 25 N/mm² at 28 days. And PCC shall be M10 (1:3:6). Maximum water-cement ratio by weight shall not exceed 0.50. Cement shall be Ordinary Portland cement (OPC) conforming to IS 8112 & IS 12269 with minimum cement content not less then table 4 of IS 456. Steel reinforcement shall be plain round hot rolled mild steel bars of characteristic strength Fy 250 N/mm² or high-yield high-bond bars of characteristic strength Fy 500 N/mm² complying with IS 1786 or IS 432. The Stripping time for formwork shall be as follows in normal circumstances when ordinary Portland cement is used:

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- Wall Columns and Vertical Faces of all Structural Member days

2

- Slabs Spanning up to 4.5m

7 days

- Slabs Spanning over 4.5m

14 days

- Beams & Arches Spanning up to 6.0m days

14

- Beams & Arches Spanning over 6.0m days.

21

(Note: Props to be refixed immediately after removal of the form work) when pozzolona cement is to be used, then the above stripping time shall change. Shuttering for Beams and Slabs shall have a camber of 4mm per meter or as specified by designer. For cantilever the camber at free end shall be 1/250 of projected length. All exposed surfaces of concrete shall be kept damp continuously for a period of atleat 7 days from the day of Placing concrete. Concrete cubes shall be cast and tested for crushing strength as per clause 15 of IS 456 : 2000. Position and arrangement of construction joint shall have the concurrence of the design engineer in charge; all construction joints shall confirm to clause 13.4 IS 456: 2000. Contractor shall use shuttering quality plywood for form work. Tolerances for formwork shall be as per case 11.10 of IS 456: 2000

1

For liquid retaining structure the concrete grade shall not be less then M25 unless otherwise specified, with cement content shall not be less then 330 kg/m³, and maximum quantity of cement shall not exceed 450 kg/m³. Construction joints shall be provided only at locations shown in the design drawings, and water bars of approved make as indicated on drawings shall be provided at all such joints as per clause 8.4 of IS 3370 (part 1). Unless noted other wise all liquid retaining side faces shall be provided with 20mm thick water proof plaster in cement mortar 1:4 with cicco no.1 or impermo of equivalent 3% by weight of cement or as per manufactures specifications. All reinforcement steel shall be of tested quality. All the bars shall be placed and maintained in position as shown in drawings; tolerance on placing of bars shall be as per clause 12.3.1 of IS 456: 2000. Multi layer bars shall be separated with spacer bars.

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10.2.5


DURABILITY, WORKMANSHIP AND MATERIALS

It is assumed that the quality of concrete, reinforcement steel and other materials and of the workmanship, as verified by PMC Company, is adequate for safety, serviceability and durability. 10.2.6

DESIGN PROCESS

The Design of this building includes design for durability, construction and use in service as a whole. Design process of this building compliance with all the codal provisions & standards for materials, production, workmanship and use of structure in service. 10.2.7

DEAD LOADS

Dead loads shall be in accordance to IS:875 Part 1 Reinforced Cement Concrete Plain Cement Concrete Roof Dead Load False Ceiling Solid Concrete Block Masonry Density of dry Soil Density of wet Soil 10.2.8

: : :

: 25 kN/m³ : 24 kN/m³ : 0.1 kN/m² NA : 24 kN/m³ 18 kN/m³ 21 kN/m³

IMPOSED LOADS

Live loads shall be in accordance to IS 875 Part 2 Roof Live Load

:

0.75 kN/m²

Collateral, Wind loads & Seismic Loads are same as mentioned above in PEB design Parameters. 10.2.9

1 10.2.10

LOAD COMBINATIONS As mentioned in clause 11.1.8 above in this document FIRE RESISTANCE All the building shall be designed to be fire resistant with a fire rating of 3 hours. The columns shall be designed for a full length to be independent of the tie beams at 2.4 m level from the FFL, as the width of the beams at this level is restricted to 200mm to flush with the wall thickness, for the following reasons listed below,

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•

Functional requirement on the inside of the building

•

Aesthetic requirement on the outside of building

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To avoid the frequent maintenance requirement and the problem of dust accumulation. •

10.2.11

ALLOWABLE DEFLECTION Allowable deflection for RCC members shall not be more than L/250 where L is the span of member

10.2.12

STABILITY RATIOS The stability of structures shall be checked for all conditions. In no case, shall the factor of Safety is less than the value given in the following table: Minimum factor of safety against overturning & sliding shall be 1.4 for all structures Minimum factor of safety against uplift shall be 1.2 for all structures The coefficient of friction between Soil & Concrete foundation is considered as 0.4 for sliding. The weight of soil over foundation shall be included in the load causing frictional forces. The passive resistance of the soil within 0.4 m of the ground surface shall not be considered for the sliding check. For Seismic and wind combination, the safe bearing capacity can be increased by 25%.

10.2.13

CLEAR COVER TO REINFORCEMENT THE NOMINAL COVER SHALL BE PROVIDED IN ACCORDANCE TO IS 456: 2000 Clause 26.4 & 26.4.3 UNLESS NOTED IN THE DRAWINGS: (REFER NOTE-1 BELOW) •

Footing

50mm

•

Raft Slab Bottom

•

Raft Slab Top

25mm

•

Pedestal

40mm

•

Column

40mm

•

Beam

20mm

•

Slabs, Canopy

For Bars > 12mm, Cover: 20mm

50mm

For Bars < 12mm, Cover: 15mm •

Waist Slab, Chajja

For Bars > 12mm, Cover: 20mm

For Bars < 12mm, Cover: 15mm

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•

RCC Wall

For Liquid Face, Cover: 25mm For Earth Face, Cover: 50mm

NOTE-1: "M/s SEMAC Ltd, the Consultant, have considered Cover to

1

10.2.14

Reinforcement based on IS: 456 - 2000, IS: 1642 - 1989 and SP – 34 and equivalent British Standard. Accordingly, the structural members (Beam, Slab and Columns) were designed and drawings issued. During the meeting dated 5th Feb 2011 with ITC structural team, it was informed by ITC team to adopt Nominal Cover to Reinforcement as per clause 26.4.3 of IS: 456 - 2000 which is also a part of ITC standardization process and accordingly design the structural members, hereafter for phase II and amenities block" (Reinforcement Cover requirement for Phase I of this project is mentioned in the REV 0 of structural DBR).

MINIMUM COVER TO FOUNDATION BOLTS Minimum distance from the centerline of foundation/anchor bolt to the edge of pedestal shall be the maximum of the following: - Clear distance from the edge of the base plate/base frame to the outer edge of the pedestal shall be minimum 50 mm. - Clear distance from the face of the pocket to the outer edge of the pedestal shall be 100 mm. - Clear distance from the edge of the sleeve or anchor plate to the edge of the pedestal shall be 100 mm.

10.2.15

MINIMUM THICKNESS OF CONCRETE ELEMENTS Flat footings (all types including raft foundations without beams) .Tapered footing shall not have thickness less than 150mm at edge Underground Pit and liquid retaining structure a) wall, 150mm b) base slab, 200mm Slab thickness in raft with beam 150, Floor slab 100, Drain/cable trench 100, Blinding concrete 75

10.2.16

MINIMUM REINFORCEMENT Minimum reinforcement shall be as per the codal requirements. Minimum reinforcement in any member shall in no case be less than that specified in IS: 456 for various structural elements such as walls, columns, beams and slabs.

10.2.17

FOUNDATIONS Design of foundations shall be in accordance with IS. The coefficient of friction between concrete surfaces and undisturbed soil shall be taken as 0.4. Anchor bolts shall be as per suppliers details. The design of structures supporting

STRUCTURAL - DBR

CLIENT


machines shall be carried out on the basis of manufacturers' information on loads, their mode of action and vibration characteristics. Foundations shall be designed so that the natural frequency of the foundation/soil system is sufficiently away from the operating frequency of the machine. The mass of the machinery foundation should be more than the machine mass.

STRUCTURAL - DBR

Civil- Structural Dbr

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