Project 2_Design & Analysis of a Hostel building at Guwahati, Assam

AIM - Design & Analysis of a Hostel building at Guwahati, Assam G+3 using etabs, using the reference of

• IS 875 part 1
• IS 875 part 2
• IS 13920
• IS 1893
• IS 2911 part 2
• IS 456
• SP 34

and detail the structural members like beam and column and also design the foundation in safe and detail it accordingly.

PROCEDURE

- FIRST WE HAVE TO PREPARE A COLUMN GRID LAYOUT IN AUTOCAD USING THE ARCHITECTUTAL DRAWING FOR THE REFERENCE THAT CAN USED IN ETABS FOR GRID CUSTOMIZATION.

GRID LAYOUT BELOW

NOTE -THE SPACING OR THE CONSTRUCTION JOINT IS PROVIDED BECAUSE ALONG X DIRECTION THE LENGTH IS MORE THAN 60MTRS FOR EXPANSION AND CONTRACTION PURPOSE WE HAVE PROVIDED 75MM JOINT

-THEN GO TO CUSTOM GRID AND CUSTOM STOREY OPTION OF ETABS AND PUT THE REQ SPACING ACCORDINGLY AND ADD STOREY HEIGHT.

- ADD SECTION PROPERTIES OF BEAMS - 400X600MM, COLUMN - 450X650MM AND SLAB- 150MM IN THE ETABS ALSO ADD MATERIAL PROPERTIES LIKE CONCRETE - M25 AND STEEL FE500 AND FE450, AND ASSIGN THAT TO THE STRUCTURE.

- AFTER GEOMETRIC MODELLING AND ADDING SECTION PROPERTY MODEL LOOKS LIKE THIS

-AFTER ADDING THIS WE CAN DEFINE THE LOADS LIKE FLOOR LOADS - 2KN/SQM AND FINISHES - 1KN/SQM AND ALSO BRICKWALL LOADS- 3.5KN/M FOR ALL FLOOR EXCEPT TERRACE, FOR TERRACE IT IS 1KN/M RESPECTIVELY SINCE WE ARE DEALING WITH THE STRUCTURE IN SEISMIC ZONE 5, WE HAVE TO CONSIDER THE EQUIVALENT LATERAL FORCE.

• AT TERRACE THERE IS ONLY PARAPET WALL HENCE THE WALL LOAD IS ASSIGNED TO THE BOUNDRY BEAMS ONLYS

- IN LOAD CASES WE HAVE TO ADD EQUIVALENT LATERAL FORCE IN EQX,EQ-X, EQ+X AND EQY, EQ-Y,EQ+Y DIRECTIONS WITH TIME PERIOD OF X AND Y.

TIME PERIOD CALCULATIONS

• IS 1893 TABLE 8 FOR IMPORTANCE FACTOR - 1.2
• IS 1893 TABLE 3 FOR ZONE FACTOR Z = 0.36
• IS 1893 TABLE 9 POINT ii RESPONSE REDUCTION - 5
• IS 1893 CLAUSE 7.6.2 PG 24 Ta= 0.09xh / √d
• SOIL TYPE AS GIVEN - III

height h = 18.7mtrs d in X direction is 67.62mtrs and in Y direction is 13.3mtrs

time period in x = 0.204sec

time period in y = 0.460sec

- Mass source should be assigned according to IS 1893 TABLE NO 10 FOR LIVE LOAD UPTO 3KN/SQM = 25% and more than 3KN/SQM = 50%

- ADD MODAL MASS ACC TO IS 1893 CLAUSE 7.7.5.2

-ASSIGN DIAPHARAGM TO THE STRUCTURE BECAUSE WE WILL DO EQUIVALENT LATERAL FORCE ANALYSIS

- CHECK IF ALL THE LOADS ARE APPLIED PROPERLY TO THE STRUCTURE AND ADD LIVE LOAD REDUCTION FACTOR THIS IS USED SINCE WE KNOW THAT LIVE LOAD AT FLOOR ALL THE TIME WILL NOT BE AT ITS MAX CAPACITY HENCE WE USE THIS FACTOR.

- CHECK THE STRUCTURE FOR ANY MODELLING ERROR IF OKAY RUN THE ANALYSIS

CHECKS TO BE PERFORMED AFTER ANALYSIS

• TORSIONAL IRREGULARITY - IS 1893 TABLE 5 TORSIONAL MODE TIME PERIOD SHOULD BE LESS THAN THE TIME PERIOD IN X AND Y DIRECTION HERE WE HAVE 0.99S WHICH IS LESS THAN MODE 1 AND 2 HENCE OKAY.

• VERTICLE IRREGULARITY - IS 1893 TABLE 6 CLAUSE 7 FIRST 3 MODES SHOULD CONTRIBUTE MORE THAN 65% IN MASS PARTICIPATION FACTOR IN EACH PRINCIPAL DIRECTION=90%

• INTER STOREY DRIFT - INTER STOREY DRIFT SHOULD NOT EXCEED 0.004 IN BOTH DIRECTION IN EQX ITS LESS THAN 4MM BUT IN Y THE BUILDING HAS TO BE STIFFER

NOTE - THIS IS NOT THE PROJECT DEMAND BUT I MADE A STRUCTURE WITH SHEAR WALL AND ACHEIVED THE DESIRED STIFFNESS IN BOTH DIRECTIONS AND THE SHEAR WALLS TAKE 80% BASE SHEAR TOO.

PLACEMENT OF SHEARWALL IN STRUCTURE

STOREY DRIFT IN SHEAR WALL IS LESS THAN 4MM IN BOTH THE DIRECTIONS.

- AFTER SUCESSFULL ANALYSIS WE SHOULD START THE DESIGNING USING DESIGN COMMAND AND CHECK IF ALL MEMBER PASSED DESIGN.

DETAILING OF STRUCTURAL MEMBERS USING ETABS DATA

BEAM DETAILING

CALCULATION OF LONGITUDNAL R/F TOP BAR

• ASTREQ AT THE LEFT AND RIGHT SUPPORT IS 1132 AND 1156MMSQ AND AT MID ITS 371MMSQ
• WE PROVIDE 2BARS 25MM BOTH END TILL L/3 AND 2BARS 16MM THROUGHOUT
• AST PROVIDED AT BOTH END WILL BE 1383MMSQ AND MID WILL BE 401MMSQ WHICH IS MORE THAN ASTREQ HENCE SAFE

CALCULATION OF LONGITUDNAL R/F TOP BAR

• ASTREQ AT THE LEFT AND RIGHT SUPPORT IS 663 AND 666 MMSQ AND AT MID ITS 524 MMSQ
• WE PROVIDE 4 BARS 16MM THROUGHOUT
• AST PROVIDED WILL BE 803 MMSQ WHICH IS MORE THAN ASTREQ HENCE SAFE

NOTE - anchorage length acc to is 13920-2016 clause 6.2.5 is Ld+10Db-bend deductions,16mm bar is 1021mm, and 25mm bar is 1595mm.

CALCULATION OF SHEAR R/F

NOTE -ACCORDING TO IS 13920 THE SPACING FROM EDGES SHOULD BE 2D, WHERE D IS EFFECTIVE DEPTH AND SPACING AT MID SHOILD NOT BE GREATER THAN D/2 WHICH IS 225MM CLAUSE 6.3.5.2, SPACING SHALL NOT BE GREATER THAN 100MM AT SUPTR

DETAILED BEAM DRAWING

NOW WE DETAIL THE COLUMN FROM THE ETABS OUTPUT

SPLICE ZONE IS PROVIDED BECAUSE THE MAX BAR LENGHT IS 12MTRS HENCE WE HAVE TO PROVIDE THAT ACC TO IS 13920. PDF ATTACHED BELOW OF DRAWING

THE FLOOR LAYOUT

PDF ATTACHED BELOW

- NOW WE PROCEED TO DESIGN OF FOUNDATION FOR THIS STRUCTURE USING SAFE SOFTWARE, FIRST WE HAVE TO IMPORT THE BASE REACTIONS USING EXPORT OPTION IN ETABS AND SELCTING ALL THE LOADS AND LOAD COMBINATIONS.

- THE OPEN THAT FILE ON SAFE.

PROCEDURE TO DESIGN PILE FOUNDATION

- ADD MATERIAL AND SECTION PROPERTIES, CONC M25 AND STEEL FE 500 AND FE 415 FOR SHEAR R/F OF TIE BEAM

- ADD SECTION PROPERTIES OF PILE, PILECAP 500MMDIA AND COLUMN STIFFNESS

- THEN USING THE COMMAND QUICK DRAW AREA AROUND POINTS WE CAN DRAW PILES AND ADD THE CENTER POINT FOR PILECAP USING DRAW POINT COMMAND.

- THE CENTER TO CENTER DISTANCE BETWEEN 2 PILECAP SHOULD BE 2.5X DIA OF BAR OR 3 X DIA OF BAR

HERE WE USED 2.5X DIA OF BAR = 2.5X0.5= 1.25MTRS

- THE DISTANCE FROM BOUNDARY TO PILECAP SHOULD BE AROUND 200-300MM, HERE WE TOOK 200MM.

- AFTER ADDING PILES AND PILECAP WE SHOULD ADD COLUMN AND THEN SELECTING THE CENTER POINT OF THE PILE WE SHOULD ASSIGN SPRING POINT FROM ASSIGN - SUPPORT DATA.

- THE VALUE OF TRANZATION Z = AE/L WHERE A IS AREA OF PILECAP, E IS ELASTIC MODULUS AND L IS THE LENGTH OF PILE

• AREA A = 3.14/4 X 500 X 500 = 196250MMSQ
• E = 25000
• L = 10000MM
• THEREFORE 196250X25000/ 10000 = 490625 N/MM WHICH IS 490.625KN/MM

-AFTER ASSIGNING THE SPRING LOAD WE HAVE TO CHANGE THE STEEL TO FE500 IN ALL PILES.

-ADD THE TIE BEAM = 450*500 [450 IS SAME AS WIDHT OF COLUMN,500 SAME AS DEPTH OF PILE ] TO AVOID DIFFERENTIAL SETTLEMENT AND ADD DESIGN STRIPS FOR R/F OF PILES.

-AFTER RUNNING THE ANALYSIS WE SHOULD CHECK THE FOLLWING THINGS TO SEE IF WE DESIGN THE FOUNDATION APPROPRIATELY.

• DEFLECTION CHECK - THE LARGEST DEFELCTION IS OF 1.60MM WHICH IS SAFE

• REACTION FORCES - THIS CHECK IS USED TO SEE HOW MUCH LOAD IS TAKEN UP BY EACH PILES, THE MAX IS AROUND 190KN BUT THE CAPACITY IS 280KN HENCE SAFE.

• PUNCHING SHEAR CHECK - THE VALUES OF PUNCHING SHEAR SHOULD BE LESS THAN 1 WE HAVE ACHIEVED THAT.

- PROCEED TO DETALING OF TIE BEAM AND PILE

PDF ATTACHED BELOW

THANK YOU. I HOPE I HAVE DONE ALL THINGS CORRECTLY AND FOLLOWED THE DESIGN PROCEDURE