Codal Practices for Rcc Design Part a General by VKMehta

INDIAN CODAL PRACTICES

DESIGN OF RCC MEMBERS PART A :GENERAL by VK MEHTA

RCC DESIGN

PART A :GENERAL PART B: DESIGN ASPECTS PART C: DETAILING REQUIREMENTS REQUIREMENTS

PART A GENERAL

CRITERIA FOR MEMBER  DESIGN 

ROBUSTNESS

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SAFETY AND DURABILITY

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FITNESS FOR PURPOSE

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ECONOMICS/COST

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USERS COMFORTS

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EXTERNAL APPEARANCE

CRITERIA FOR MEMBER DESIGN 

ROBUSTNESS: careful planning in choosing a Stable & strong configuration with lateral stability in two orthogonal direction ( adequate stiffness /structural integrity to be ensured for load transfer by   providing columns/beams/horizontal columns/beams/horizontal diaphragm, slab/bracing. Foundation adequacy).

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 planned planned and design so that the local failure of one member sd. not lead to global collapse of structure .

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Ductility detailing of the structural sstru tructural ctural members.

CRITERIA FOR MEMBER  DESIGN 

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SAFETY AND DURABILITY:

Structural design to conform to codal & accepted design practices.

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use of right material ,proper loading , design d esign design detailing, protections measures , fire resistance and quality construction .

FITNESS FOR PURPOSE:

Over all structural configurations should allow unrestricted movement with adequate approaches & escape routes.

CRITERIA FOR MEMBER DESIGN 

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ECONOMICS/COST: 

cost- time economics/ build ability of the selected configuration.

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Minimize maintenance cost

USERS COMFORTS: 

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minimise vibration/noise level due to vibrating machine in structure, vertical/lateral deflection to be within limits

EXTERNAL APPEARANCE:

Good aesthetic appearance / avoidance of  cracks/ spalling ,leaking and staining .

degradation

INTERNATIONAL CODAL PRACTICES COUNT NO TITLE REMARK RY  INDIAN

Plain & Reinforced Concrete-code of  Practice BRITISH Structural use of  AMERIC ACI 318 concrete Building Code AN requirements for Reinforced Concrete AUSTRA AS 3600 Concrete structures LIA GERMAN DIN Structural use of  EURO

IS 456:200 0 BS 8110

1045

concrete

S

Part 1 to 3

 

MATERIAL 

CEMENT 

ORDINARY PORTLAND CEMENT GRADE 33/43/53( IS 269/8112/12269)

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PORTLAND SLAG CEMENT (IS 455)

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SULPHATE RESISTING CEMENT (IS 12330)

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RAPID HARDENING CEMENT (IS 8041)

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PORTLAND POZZOLANA CEMENT(IS 1489).

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CEMENT TYPES AS PER ACI

MATERIAL 

REBARS 

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HIGH STRENGTH DEFORMED DEFORMED BARS GRADE GRADE FE 500 (IS 1786) 

MILD STEEL (IS 432)

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MAIN SUPPLIER:TATA TISCON(CRS)/SAIL(TMT)

COATING OF REBARS/OTHER TYPES :

FBEC -EPOXY COATED (PSL HOLDING) (IS 13920/ASTM A775)

COATED BARS DEVELOPED BY CECRI(KARAIKUDI). GAVLANISED/STAINLESS STEEL GAVLANISED/STAINLESS CATHODIC PROTECTION OF REBARS

DURABLE CONCRETE 

A DURABLE CONCRETE IS ONE THAT PERFORM SATISFACTORILY IN THE WORKING ENVIRONMENT DURING ITS ANTICIPATORY EXPOSURE CONDITION.

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THE CONRETE USED SHALL PROTECT THE REBARS CORROSION AND BE IMPERMIABLE .

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ADEQUATE COVER TO REBARS

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GOOD QUALITY CONTROL OF MATERIAL

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SUITABLE CONTROL OF CEMENT AND WC RATIO

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WORKMANSHIP COMPACTION & PROPER  CURING

CONCRETE GRADES GROUP

STANDARD GRADE

HIGH GRADE

GRADE M25 TO 30 M35 TO 40 40 TO 55 60 TO 80

REMARKS USED IN GENERAL MARINE APPLICATION PRESTRESS CO CON NCRET ETE E SPECIALISED APPLICATIONS

CONCRETE GRADE SELECTION WITH CEMENT CONTENTS & W/C RATIO EXPOSUR E

EXPOSURE CONDITIONS

GRAD E

Cement contents kg/m3

MILD

Protected against weather in general

M20

300

0.55

MODERA Concrete sheltered  TE from severe rain

M25

300

0.50

SEVERE

VERY SEVERE

Exposed to severe rain, alternate wetting & drying Exposed to sea water

EXTREM  Tidal zone & E aggressive

w/c ratio

REMARKS

M30

320

0.45

Common ly used

M35

340

0.45

COASTA L

M40

360

0.40

ENVIRON MENT

EXPANSION JOINTS 

Structure should be separated by Expansion  joints:

1) Structure with large Plan dimensions.

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2) L shape or Irregular shape in Plan and elevation.

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IS 456 SPECIFY EXPANSION JOINTS WHEREVER BUILDING EXCEED 45M LENGTH.

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Provide adequate gap and joints should be detailed to allow free structural movements at these locations.

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Gap of 25-50 mm is generally provided.

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TYPICAL DETAIL

EXPANSION JOINT SPACING (Technical report #6 5,Technical research council ,USA)

EXPANSION JOINT SPACING 

SUGGESTED SPACING FOR RCC FRAMED STRUCTURE:-

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USE ~60M FOR OPEN FRAME STRUCTURE LIKE TECH STR./PIPE RACK.

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REDUCE APPROPRIATELY FOR  COVERED MULTISTOREY BUILDING.

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DESIGN FOR THERMAL MOVEMENT IF LONGER SPACING MORE THAN ABOVE & IS ESSENTIAL.

ATTACHMENTS

Types of cement as per ACI 318

STRESS STRAIN DIAGRAM FOR  DIFERRENT STEEL GRADES

NOTES:-EXPANSION JOINT SPACING

TYPICAL BUILDING WITH EXP JOINTS

TYPICAL EXPANSION JOINT DETAIL