mat foundation.doc

7/30/2019 Mat foundation.doc

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MAT FOUNDATION FEM

DATA:Width l : 9.50mLength : 10.0m


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STEP 1 (Creation of Geometry):

File New Project Select space File Name= mat foundationUnit KNS Met. Next Add plate Finish.Type minimum Data on Data area.Node X Y Z

1 0 0 0

2 0.50 0 03 0.0 0.0 0.504 0.50 0.0 0.50

Add 4 noded plates. Pick node 1,3,4,2.(Note: Plate shall be preferably connected in anticlockwise direction.)Select Plate 1 created. Click Translational Repeat icon.Global direction XDefault spacing =0.50mNo. of steps =18 (9.50-0.50)/0.5 =18)19 Plate elements created in X direction. Select 19 Plates created.

Click Translational Repeat icon.Global Direction ZDefault spacing =0.50mNo. of steps =19 (10.0-0.50)/0.5 =19)

STPE 2 (Member Property):

Main menu Commands Property Thickness Plate 1 =0.45 Add.Select all the plates using Plate cursor Assign.

Step 3 (Support condition):Calculation of Sub grade reaction

SBC =120KN/m2

Elastic mat subgrade reaction value is KN/m2/mAs per Bowels subgrade modulus =40 x FOS x SBC(for 25mm settlement)FOS =2.5 to 3Sub grade modulus =40 x (2.5 to 3) x SBC

= 100 to 120 tomes SBC = XFor 50mm settlement =X/2For 75mm settlement = X/3 (OR)Subgrade reaction = SBC/ settlement of 25 mm

=100KN/m2

/0.025 =4000 KN/m2

/m.Ks =subgrade reaction = 100 to 120 times SBC say 100 x 120

=100x120 =12,000KN/m2

Ka= area x ks= (0.25x 0.25) x 12000=0.0625 x 12000 = 750KN/m3

Kb= area x ks= (0.5x 0.5/2) x 12000


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=0.125 x 12000 = 1500KN/m3

Kc= area x ks= (0.50x 0.50) x 12000=0.25 x 12000 = 3000KN/m3

General Support create click Fixed butFor ka ky =750KN/m3

For kb ky = 1500KN/m3

For kc ky = 3000KN/m3

Select corner node ka Ky=750KN/m3 Assign.Select intermediate end plates for kb Ky =1500KN/m3 assign.Select all intermediate node kc for Ky=3000KN/m3 Assign.Step 4 (Loading):Main menu Commands Loading Primary load Load case 1 =Dead

Load Add.Load case 2=Live Load Add close.Select load case 1 (Dead Load) Add.Self weight Factor =-1. Direction Y.Dead Load (from column reaction) Fy=-250KN Add.Select Fy =-250 KN select all column support node Assign.Select Load case 2 (Live load) Add .Fy=-150KN Add.Select Fy =-150KN Select all column support nodes Assign.Main menu Commands Loading Load comb Load comb 3

Default =1.50

Add

Close.Main menu Commands Loading Load list (selecting design load)Ok Close.

Step 5(Analysis Type):Main menu Commands Analysis Perform Analysis No Print Ok.

Step 6 (Post Analysis print):Main menuCommands Post analysis print Support reactions Ok.

Step 7(Post analysis print):

Main menu Commands Design Concrete Design Currentcode=IS456 Main menu Tools Set current input

Step 8 9analysis):Main menu Analysis Run Analysis Done.


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Front view Select the beam in first top 4 levels by windowing Go to

Isometric view and confirm the selection of beams in X Direction and Z

direction of top 4 levels beams From Main menu Commands

Member properties Prismatic Rectangular Yd=0.33 Zd=0.23

Assign De select the member and select beam at lower most level

(Plinth beam) From Main menu Commands Member Property

Prismatic Rectangular YD=0.3 ZD=0.23 Assign Close De select

the member and select column member (Go to top view) window the type

1 column of outer column From Main menu Commands Member

Property Prismatic Rectangular YD=0.3 ZD=0.23 Assign

Confirm by viewing the column in isometric view. Go to Top view

Window the type 2 column of outer column From Main view

Commands Member Property Prismatic Rectangular YD=0.23

ZD=0.30

Assign

Confirm by viewing the column in isometric view.

Go to Top view Window the type 3 column in intermediate position

From Main view Commands Member Property Prismatic

Rectangular YD=0.33 ZD=0.23 Assign Confirm by viewing the column

in isometric view.

To confirm whether any missing property

Main menu Select Missing attributes Missing Property No entity

missing Property is found Ok.

De select the member.

STEP 3 (Supports):


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Change to Node cursor (joint) and select the nodes (joints).

(If more than one node use CTRL key and select the nodes) From Main

menu Click Front view icon

Commands Support specification Fixed Assign Close

De select the nodes and change to beam cursor.

STEP 4 (Loading ):

From Main menu Commands Loading Primary Load Load case

1=Dead(load) Add Load case2= Live(load) Add Load case

1(dead load) Add Self weight(dead load) Factor=-->1

Direction Y (Beams and columns) Floor load (Dead load of slab)

Pressure=-->3.5(self weight of slab= 2.50 + Floor finish=1.0)

Define Y range Mini=5.50 (2.50+3.0); Max=14.50

Define X range Mini=0; Max=7.01 (3.05+3.96)

Define Z range Mini=0; Max =10.36 (2.74+3.96+3.66) Add Member

load (wall loads) Uniform force W1=--12 (9 wall load Add

W1=-6 (41/2 wall load) Add Close Assign 9 wall load to external

beams and 41/2 wall load to internal beams in top view Select load

case 2(live load) Add Floor load (Live load on slab) Pressure=-2

(Live load)

Define Y range Mini=5.50 Max =14.50

Define X range Mini=0 Max=7.01

Define Z range Mini=0 Max=10.36 Add Close

Main menu commandLoading Load combination Load comb 3

Default=1.50


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Available loadLoad case 1Load case 2

>>>

>

2002.


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2. Load Definitions Seismic definitions Add.

3.Seismic Parameter screen appear.


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Zone (for zone III) = 0.016Response reduction Factor =5 (If ductile is provided RF=5; If ductile is

not provided RF =3)Importance factor (I) =1 (For important building I=1.5 & all other

building I=1.0)Soil site factor (SS) =2 ( For hard soil SS=1; Medium soil

SS=2; Soft soil SS=3)Type of Structure (ST) =1 (ST for RC Frame=1; Steel frame =2;All

other buildings =3)

Period in X Direction = }(Optional)Period in Z Direction = } (Optional)Depth of Foundation DT) = 2.50 Add.4. Self weight Add.

5. Copy the Dead Load and Live Load already given below the selfweight.6. Edit Edit input command file.In the Seismic Definition below the self weight, do the following:(i)The member load copied and pasted with load changing to weight(ii)The ve sign changed to + ve sign, GY to be deleted


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(iii)Also, the Floor load copied and pasted with load changing to weight(iv)The ve sign changed to + ve sign GY to be deleted(v)The live load may be reduced to 0.5 times actual Live Load if LL >3.0

KN/m20.25 times actual Live Load if LL< 3.0 KN/m2).

(vi) The Live Load on roof slab need not be considered for this case.


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Steps:1. Main menu Select Beams parallel to Y2. View View selected objects only.3. Main menu Commands Support Specifications Pinned

Assign.4. Main menu Commands Post analysis Support Reactions.5. Main menu Analysis Run analysis.6. Main menu View Tables Support reactions Ok.7. Select the joint No. and Force Y.8. Copy and Past it in a Excell sheet separately.9. Edit the same as follow:

Joint No. Weight Fy(e.g) 3 weight 8.48.10. Copy the above joint weight and paste it below

Define 1893 loadZone 0.15 RF 5 I 1.0 SS 2 ST 1 DM 0.05 Df 2.5.

..3 weight 8.48

mat foundation.doc

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