Creating Default.edb File

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Creating ETABS Default.edb file

Creating Default.edb file for ETABS

When you start ETABS and click on New Model…, it asks

to choose edb file, either default or custom. In this tutorial you will be able

to create a default.edb file. The advantage for this option is, you can immediately start working on building the model

instead of first defining the material and section properties. The choose.edb

option is for selecting an ETABS file which is not default but you want to use

parameters of the model used in other project.

So, in this tutorial you are going to make a default edb

file containing all the information, units and options in which you want to

work and don’t want to waste your time every time you start a new model.

We will work in SI units in this

tutorial.

1-Start ETABS

3-Select kN-m from lower right

corner units drop box.

4-Start a new

model and when asked for edb file, Choose No, because at this time you are

creating your first edb default file.

5-Select “Grid Only”

option and press ok.

No we will work menu by menu. So first

one is file menu.

FILE menu

i-Print Setup

Select your default printer and paper size.

DEFINE menu

Select your units to be N-mm

i-Material Properties

Select add new materials and define different concrete

strengths you use commonly. For example

Conc. 21: 21N/mm² compressive strength and 420N/mm²

steel strength with 4700√f’c as modulus of Elasticity.

Conc. 25, Conc. 30, Conc. 35, Conc. 40

etc.

ii-Frame Sections

Select the first section in the list then scroll to the

bottom and while holding the Ctrl button select the last section in the list,

then click on delete button. All frame sections except the last one will not be

deleted. You can add new sections and once you have defined your section, you

will be able to delete also this last undesired section.

Add all the sections, you want to

be in your project, for example rectangular, circular etc. Define as many

sections as you can. Sometimes, you want to optimize your sections and want to

increase say a beam’s depth by 50mm and check if it is passing or not. So

first define the smallest section and then define all other sections with depth

increment of 50mm (or 3 inches) keeping the width same. Once you have reached

the limit for the depth of the members, say 1000mm then start defining the

sections with width increment. This step is most time consuming, but as you do

it, I bet it will be much time saving for your next models. If a beam say

250x300 is failing, you will not need to define another section say 250x400,

rather you will just select it from the pre-defined sections and change the

section to see if its passing or not and so on. You MUST concentrate hard on

this step and on cover values and material of sections, because once you define

the sections, it will be hard to catch the error in

cover or depth or width values. For an example you can have your sections like

this:-

B-250x300 B-300x300 C-300x300

B-250x350 B-300x350 C-400X400

B-250x400 B-300x400 C-500X500

Note:

Cover to rebar center is distance b/w edge of beam to

centroid of reinforcement. I recommend you to use two layers of the main bars

you use commonly for top and bottom reinforcement and #3 bars or (T10) bars for

stirrups and 40mm cover. Remember when you use two layers, the distance b/w

bars (vertically) should be larger of 25mm(1”)

or main bar dia. For example for moderate height and size of

buildings. You can 2 layers T-16 main T-10 stirrups so cover = depth –

40cover – 10stirrups – 16 (1layer of T016)-(25/2mm) for half of

dist b/w bars. = depth – 80.

iii-Wall/Slab/Deck Sections

Define all your slab sections here. For example 2way150 (two

way slab 150thick) 1way125(one way slab 125 thick)

etc. Please select material for each section carefully. Membrane and bending

thickness is same mostly. But if you have pre-cast slab with 75mm topping, your

bending thickness will be 75mm and your membrane thickness will total thickness

(slab+topping). If you have flat slab, select shell option, otherwise membrane

option. For one way slab use special one way slab

distribution option.

SHELL: Transfers load to horizontal boundary elements (beams

in two way slab with beams).

MEMBRANE: Transfers load to boundary nodes (columns in flat

slab).

Slab load is distributed by 45 degree tributary area method.

iv-Static Load Cases

Define all your static load cases. To be simple, define

Dead, Live, EQ and wind loads.

Put dead load multiplier 1 in one of any dead load case. No

need to put separate Self wt load case. Usually dead load cases are DL, WALLS,Finishes. For simplicity and for small projects, you can use

only 1 case as DL (including all finishes, walls, self wt) etc and one LL.

For earthquake loads, you must define four cases

EQX1- X direction + Y Eccent.

EQX2- X direction – Y Eccent.

EQY1-Y direction + X Eccent.

EQY2-Y direction – X Eccent.

Eccentricity ratio should be 0.05(5%). These four directions

are necessary for irregular buildings. If you have perfectly regular and

symmetric building, you can use only one X and one Y direction.

v-Special Seismic Load Data

Select do not use special seismic load data and press ok.

vi-Mass Source

Select “From loads” option because we will not

generally put additional masses inside our model and self weight is also being

calculated with DL (self wt. multiplier is 1). So everything will calculated based on your given loads. Use 100%DL(all dead load not just self wt.) + 25%LL (see UBC-97

code). For light buildings you can use 100%DL + 15%LL.

ANALYZE menu

i-Set analysis options

Unselect dynamic and P-Delta option, if you do not want to

use these options. (UBC Equivalent Static Process, used in moderate size

buildings.) If you run your model with dynamic option selected, you will not be

able to see static seismic calculations in summary file, even if you remove

dynamic option and run the model again. This is a bug in ETABS. So if you are

sure that you will use STATIC process, remember to check dynamic option is unselected

before running your model.

OPTIONS menu

i-Preferences>Concrete Frame Design

Select your code. For ACI, ACI-02 is best. Select seismic

design category. If you want to convert UBC Seismic zone to seismic category,

refer to ACI table R1.1.9.1 in Chapter 1. Do not change pattern load factor.

Utilization factor limit is the additional ETABS factor of safety. It’s

not recommended to change this factor also.

ii-Preferences>Reinforcement Bar Sizes

Change to your needs and delete unnecessary bar data.

iii-Preferences>Live Load Reduction

Select your parameters. Usually no live load reduction is

selected.

And that’s it. You are done. You have successfully

configured everything you needed for your next models. Now it’s the time

to save it in proper location.

Click Save As… in file menu and select the

installation folder of ETABS, if there is already default.edb file, overwrite it, otherwise save as “Default.edb”.

Now every time you start a new model and when asked to

choose edb, just select the Default.edb button and you will find all the

settings there.