DESIGN OF RCC MEMBERSDESIGN OF RCC MEMBERSPART A :GENERALPART A :GENERAL

by VK MEHTAby VK MEHTA

INDIAN CODAL PRACTICESINDIAN CODAL PRACTICES

RCC DESIGNRCC DESIGN

PART A :GENERALPART A :GENERAL

PART B: DESIGN ASPECTSPART B: DESIGN ASPECTS

PART C: DETAILING REQUIREMENTSPART C: DETAILING REQUIREMENTS

GENERALGENERAL

PART APART A

CRITERIA FOR MEMBER CRITERIA FOR MEMBER DESIGNDESIGN

ROBUSTNESSROBUSTNESS SAFETY AND DURABILITYSAFETY AND DURABILITY FITNESS FOR PURPOSEFITNESS FOR PURPOSE ECONOMICS/COSTECONOMICS/COST USERS COMFORTSUSERS COMFORTS EXTERNAL APPEARANCEEXTERNAL APPEARANCE

CRITERIA FOR MEMBER DESIGNCRITERIA FOR MEMBER DESIGN

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

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

Ductility detailing of the structural members.Ductility detailing of the structural members.

CRITERIA FOR MEMBER CRITERIA FOR MEMBER DESIGNDESIGN

SAFETY AND DURABILITY:-SAFETY AND DURABILITY:- Structural design to conform to codal & accepted Structural design to conform to codal & accepted

design practices. design practices. use of right material ,proper loading , design use of right material ,proper loading , design

detailing, protections measures , fire resistance and detailing, protections measures , fire resistance and quality construction .quality construction .

FITNESS FOR PURPOSE:-FITNESS FOR PURPOSE:- Over all structural configurations should allow Over all structural configurations should allow

unrestricted movement with adequate approaches & unrestricted movement with adequate approaches & escape routes.escape routes.

CRITERIA FOR MEMBER DESIGNCRITERIA FOR MEMBER DESIGN

ECONOMICS/COST: -ECONOMICS/COST: - cost- time economics/ build ability of the selected cost- time economics/ build ability of the selected

configuration. configuration. Minimize maintenance cost Minimize maintenance cost

USERS COMFORTS: USERS COMFORTS: minimise vibration/noise level due to vibrating machine in minimise vibration/noise level due to vibrating machine in

structure, vertical/lateral deflection to be within limitsstructure, vertical/lateral deflection to be within limits EXTERNAL APPEARANCE:-EXTERNAL APPEARANCE:-

Good aesthetic appearance / avoidance of Good aesthetic appearance / avoidance of degradation degradation

cracks/ spalling ,leaking and staining cracks/ spalling ,leaking and staining ..

INTERNATIONAL CODAL INTERNATIONAL CODAL PRACTICESPRACTICESCOUNTRY NO TITLE REMARKS

INDIAN IS 456:2000

Plain & Reinforced Concrete-code of Practice

BRITISH BS 8110 Structural use of concrete Part 1 to 3

AMERICAN ACI 318 Building Code requirements for Reinforced Concrete

AUSTRALIA AS 3600 Concrete structures

GERMAN DIN 1045 Structural use of concrete

EURO

MATERIALMATERIAL

CEMENTCEMENT ORDINARY PORTLAND CEMENT GRADE ORDINARY PORTLAND CEMENT GRADE

33/43/53( IS 269/8112/12269)33/43/53( IS 269/8112/12269) PORTLAND SLAG CEMENT (IS 455)PORTLAND SLAG CEMENT (IS 455) SULPHATE RESISTING CEMENT (IS 12330)SULPHATE RESISTING CEMENT (IS 12330) RAPID HARDENING CEMENT (IS 8041) RAPID HARDENING CEMENT (IS 8041) PORTLAND POZZOLANA CEMENT(IS 1489).PORTLAND POZZOLANA CEMENT(IS 1489). CEMENT TYPES AS PER ACICEMENT TYPES AS PER ACI

MATERIALMATERIAL REBARSREBARS

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

MILD STEEL (IS 432)MILD STEEL (IS 432) MAIN SUPPLIER:TATA TISCON(CRS)/SAIL(TMT)MAIN SUPPLIER:TATA TISCON(CRS)/SAIL(TMT)

COATING OF REBARS/OTHER TYPES :-COATING OF REBARS/OTHER TYPES :- FBEC -EPOXY COATED (PSL HOLDING) (IS FBEC -EPOXY COATED (PSL HOLDING) (IS

13920/ASTM A775)13920/ASTM A775)

COATED BARS DEVELOPED BY CECRI(KARAIKUDI).COATED BARS DEVELOPED BY CECRI(KARAIKUDI).

GAVLANISED/STAINLESS STEELGAVLANISED/STAINLESS STEEL

CATHODIC PROTECTION OF REBARSCATHODIC PROTECTION OF REBARS

DURABLE CONCRETEDURABLE CONCRETE A DURABLE CONCRETE IS ONE THAT PERFORM A DURABLE CONCRETE IS ONE THAT PERFORM

SATISFACTORILY IN THE WORKING SATISFACTORILY IN THE WORKING ENVIRONMENT DURING ITS ANTICIPATORY ENVIRONMENT DURING ITS ANTICIPATORY EXPOSURE CONDITION.EXPOSURE CONDITION.

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

ADEQUATE COVER TO REBARSADEQUATE COVER TO REBARS GOOD QUALITY CONTROL OF MATERIAL GOOD QUALITY CONTROL OF MATERIAL SUITABLE CONTROL OF CEMENT AND WC SUITABLE CONTROL OF CEMENT AND WC

RATIO RATIO WORKMANSHIP COMPACTION & PROPER WORKMANSHIP COMPACTION & PROPER

CURINGCURING

CONCRETE GRADESCONCRETE GRADES

GROUP GRADE REMARKS

STANDARD GRADE

M25 TO 30 USED IN GENERAL

M35 TO 40 MARINE APPLICATION

40 TO 55 PRESTRESS CONCRETE

HIGH GRADE 60 TO 80 SPECIALISED APPLICATIONS

CONCRETE GRADE SELECTION CONCRETE GRADE SELECTION WITH CEMENT CONTENTS & W/C WITH CEMENT CONTENTS & W/C

RATIORATIOEXPOSURE EXPOSURE CONDITIONS GRADE Cement

contents kg/m3

w/c ratio REMARKS

MILD Protected against weather in general

M20 300 0.55

MODERATE

Concrete sheltered from severe rain

M25 300 0.50

Commonly used

SEVERE Exposed to severe rain, alternate wetting & drying

M30 320 0.45

VERY SEVERE

Exposed to sea water M35 340 0.45 COASTAL ENVIRONMENT

EXTREME Tidal zone & aggressive chemical environment

M40 360 0.40

EXPANSION JOINTSEXPANSION JOINTS Structure should be separated by Expansion Structure should be separated by Expansion

joints:- joints:- 1) Structure with large Plan dimensions.1) Structure with large Plan dimensions. 2) L shape or Irregular shape in Plan and elevation.2) L shape or Irregular shape in Plan and elevation.

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

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

Gap of 25-50 mm is generally provided.Gap of 25-50 mm is generally provided. TYPICAL DETAILTYPICAL DETAIL

EXPANSION JOINT SPACINGEXPANSION JOINT SPACING(Technical report #65,Technical research council ,USA)(Technical report #65,Technical research council ,USA)

EXPANSION JOINT SPACINGEXPANSION JOINT SPACING SUGGESTED SPACING FOR RCC SUGGESTED SPACING FOR RCC

FRAMED STRUCTURE:-FRAMED STRUCTURE:- USE ~60M FOR OPEN FRAME USE ~60M FOR OPEN FRAME

STRUCTURE LIKE TECH STR./PIPE STRUCTURE LIKE TECH STR./PIPE RACK.RACK.

REDUCE APPROPRIATELY FOR REDUCE APPROPRIATELY FOR COVERED MULTISTOREY BUILDING.COVERED MULTISTOREY BUILDING.

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

ATTACHMENTS

Types of cement as per ACI 318Types of cement as per ACI 318

STRESS STRAIN DIAGRAM FOR STRESS STRAIN DIAGRAM FOR DIFERRENT STEEL GRADESDIFERRENT STEEL GRADES

NOTES:-EXPANSION JOINT NOTES:-EXPANSION JOINT SPACINGSPACING

TYPICAL BUILDING WITH TYPICAL BUILDING WITH EXP JOINTSEXP JOINTS

TYPICAL EXPANSION JOINT TYPICAL EXPANSION JOINT DETAILDETAIL