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

AIM:-To Create and Analyze the given building in ETABS 2018, the structural model has to be prepared in accordance with IS 1893 and as per IS 13920. To design the pile cap and pile reinforcement details, Tie beam connecting the pile caps, to sketch the column reinforcements, to produce the framing plan and beam detailing for ground floor.

Given data’s: -

The wall are made of AAC blocks Pile capacity -280kN, M25 Concrete Fe 500 steel, Soil type 3.

INTRODUCTIONS: -

Necessary data of the building is given below,

• The walls will be made of AAC blocks.
• The buildings rests on type 3 soil. Piles of length 10 meters and 500 mm diameter with load carrying capacity of 280 KN is to be used.
• The ground floor level will be at a height of 2 meters above existing site level to avoid flood water enter the building.
• M25 grade of concrete with Fe500 for longitudinal reinforcement and Fe 415 for shear reinforcement is to be used.
• Floor plan of the Hostel block is given below,

• Elevation of the hostel building

IS codes used in this project for reference:

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

PROCEDURE :

Data required for modelling and analysis of the building in ETABS

Beam-column layout of the hostel block 1 and hostel block 2

Pinned support, Base+ 4 storey (ground to terrace)+ mumty.

Column size is assumed as 450mm×650mm, beam size i.e. 450mm×500mm, slab of thickness 150mm.

Live load hostel building as per IS 875- part II,

• Kitchen- 2kN/m
• Dining- 4kN/m
• Living room/ Bedroom-2kN/m
• Store room-5kN/m
• Office room-2.5 kN/m
• Toilet and bathroom-2 kN/m
• Balcony -2kN/m
• Corridor passage, staircase and store room-3 kN/m
• Terrace and mumty-1 kN/m

Calculation brick wall load and floor finishing

• Density of ACC block= 6kN/m 
• Density of cement mortar= 20kN/m 
• Thickness of wall= 0.15mm 
• Height of the wall= 3.45-0.45= 3m 
• Weight of wall= (3×0.15×6) = 2.7 kN/m
• Assuming thickness of plastering=0.024m 
• Load for plastering= (3×0.024×20) = 1.44 kN/m 
• Total brick wall load= 2.7+1.44= 4.14 kN/m which is nearly equal to 4.2 kN/m. 
• Floor finishing= 1.2 kN/m3

Time factor calculation

• As per IS 1893:2016, clause-7.6.2 (c), page no-21
• Height of the building=18.7m
• Time factor in y direction where d=13.3m, Tx=((0.09×18.7)/square root(13.3))= 0.4615=0.46
• Time factor in x direction where d=66.62m, Tx=((0.09×18.7)/square root(66.62))= 0.2062=0.21

Analysis and design for beam, column and slab of the hostel building by using ETABS

STORY DATA

GRIDE DATA

MATERIAL PROPERTY DATA

FRAME PROPERTY

SLAB PROPERTY

ASSIGNING BEAMS AND COLUMN

ASSIGNING SLAB150

ASSIGN PIN SUPPORT TO BASE

LOAD PATTERNS

MASS SOURCE

ASSIGNING FRAME LOAD

ASSIGNING LIVE LOAD

LIVE LOAD REDUCTION FACTOR

LOAD CASES

LOAD CASE DATA (MODAL)

LOAD COMBINATIONS

ASSIGNING DIAPHRAGMS

MODAL SPECTRUM 

CHECK MODAL

RESULT :

Detailing of beam in the hostel block by ETABS

Design details i.e. flexural details and shear details for all the load combination of every members in the model can be checked by right clicking on the required members and directly the designs can be access.

After finding the design details, then for grids 3 at 3rd floor the detailing has been done.

Results and Discussion

Detailing rule of reinforcement concrete members

Minimum reinforcement for shrinkage and temperature

Reinforcement required for limiting cracking width

Ultimate limit state design rebar reinforcement

Ductility rebar reinforcement

RC beam detailing is chose whichever is greater among above condition 1, 2, 3 and 4.

Minimum longitudinal reinforcement as per IS 13920-2016 clause 6.2.1.

                                                       AS= 360 mm2

Minimum shear reinforcement as per IS 456-2000 clause 26.5.1.6 assuming 1 meters spacing in the formula,

                                                      ASV= 554 mm2

Development length as per IS 456-2000 clause 26.2.1

                                                   Ld= 50 × diameter of bar

                                           For 20mm dia, Ld= 50 × 20mm= 1000mm

                                           For 25 mm dia, Ld= 50 × 25mm= 1250mm

 Longitudinal reinforcement for Grid 3

 Shear reinforcement for Grid 3

BEAM CROSS SECTIONAL VIEW

Detailing of column in the hostel block by ETABS

Results and Discussion

Detailing rule of reinforcement concrete members

Minimum reinforcement for shrinkage and temperature

Ultimate limit state design rebar reinforcement

Ductility rebar reinforcement

RC beam detailing is chose whichever is greater among above condition 1, 2 and 3.

Minimum longitudinal reinforcement as per IS 456-2000 clause 26.5.3.1.

                                                         AS= 3000 mm2

Minimum shear reinforcement or transvers reinforcement as per IS 13920-2016 clause 7.4.2

8mm diameter at 300mm spacing

Development length as per IS 456-2000 clause 26.2.1

                                                     Ld= 50 × diameter of bar

Special confining reinforcement from IS 13290-2016 (clause 8.1)

Calculation of l0, which would be the maximum value among following three value i.e. 1, 2, and 3.

Larger column dimension= 750mm

(1/6)th of clear span of column

                      = (1/6) × 2800 = 812.5 mm for column of span 3450 mm.

                      = (1/6) × 2075= 345.83 mm for column of span 2400 mm.

450mm

So, l0 = 812.5 mm as it is higher value among 1, 2 and 3. So provide 825mm of l0

Calculation of confinement of spacing, which would be the minimum value among following three value i.e. 1, 2, and 3.

(1/4)th of smaller column dimension = (1/4)× 500= 125 mm

6th time of diameter of column main bar= 6× 32= 182mm

100mm

Hence the confinement of spacing is 100mm.

Calculation of amount of confinement rebar,

     Ash= 81.51257mm2

Longitudinal reinforcement of column for Grid 3B

Shear reinforcement of column for Grid 3B

COLUMN CROSS SECTION

Analysis and design for foundation of the hostel building by using SAFE with ETABS outputs

Data required for SAFE analysis and design,

Go to file click on export and select the safe v12.fk.

A tab will appear then click on the story as base and select the  loads and loads from above click on the combination click ok,

Goto SAFE 2016 and fo to file click import and select the file and save the file as FDB.

Go to dispay click on the show loads select dead above and love above the values will be appeared.

Given  data:-

Column of size:- 450mm *600 mm  & 600mm*450m m

pile has a load carrying capacity of 280kN

Pile length-16 m and dia of pile -500 mm

SBC-150kN/m^2

Solution:

Number of piles=Total Axial load/pile capacity=(1.5DL+1.5LL)/280= numbers

Piles in the springs are defined as spring so for that the spring constant

K=EA/L

E=5000(fck)^0.5=5000(25)^0.5=25000 N/mm^2

Area of pile =22/7*d^2=3.142*(500)^2/4=196375m^2

L-10000m

K=25000*0.7855/16=306835.9N/mm==419.

Spacing of the piles as per clause number 6.6.2 of IS  2911  the spacing between the piles =2.5dia of the piles =2.5*500=1250mm

PROCEDURE :

• Now in the next step we have to define the material properties for go to define and define the material properties of Concrete and Reinforcement properties  Fe500 & Fe 415.
• Select the values .
• Go to define section properties and define pile caps ,pile Dia , and column
• Add new , defined pile cap pile 500 as Mat , and  Column as Stiff.
• Click on the quick draw around the plots a window will  open there insert the columns sizes and these columns to their specified positions. Columns  should be stated as stiff material.
• In the next step pile caps needs to be drawn for that go to Quick draw slab command select pile caps and add it. Piles and pile cap should be stated as stiff material.
• Select the pile caps and changed the rebar material as Fe 500 .
• Next go to draw and draw point and a window will open up there draw the points where piles are to be drawn.
• Now again select the quick dfaw around the pints there select the property circular slab add piles dia  in this case 0.5m and add to the points. Select these piles and again check for the rebar materials.
• Now we have to define all the piles  as spring for that go to define
• select soil spring properties add new property there click on compression only and add the calculation value of K=EA?L.
• Select all the piles and go to assign and select support data and select spring properties and assign it.
• Go to define and select the define beam and define the tie beams whose thickness should be as of pile caps.
• Check weather the rebar material is Fe 500 under design preferences
• Go to define and define the load combinations sls and uls
• Go to design and design preferences
• Save the model and run the Analysis
• Deformed shapes showed that deformations are negligible
• Assign add the design strips
• Run the analysis
• Deformed shape all the values are less than 25 mm hence ok.
• Now go to display and click on the punching shear the values we have go are less than 1 hence ok.
• Now go to display and select slab design.
• All the reinforcement details will be available
• For X DIRECTION MIDDLE STRIP

maximum Reinforcement was

              For Top:-  29834 mm^2/m=29834/3.3=9041 mm^2=28 nos. 20 mm dia are provided

              For Bottom-13326mm^2/m=4038 mm^2=13 nos. 20 mm dia are provided

For layer Y direction

maximum Reinforcement was

              For Top:- 19926= 3831mm^2/m=12 nos of 20 mm dia are provided

              For Bottom-22784mm^2/m=4398 mm^2=14 nos 20 mm dia are provided