ETABS Building Design Manual

ETABS Building Design Manual

Civilax.com

1) INITIAL CONSIDERATIONS

Figure 1.1.-Structure Analysis and design Dimensional dual reinforced concrete structure will be analyzed. The project consists of a 5-level structure whose geometric dimensions in plan and elevation are shown in Figure 1.2 and 1.3.

1.1.

Structural drawings

Presented below outlines plan and elevations that serve to the model drawing.

www.civilax.com

Page 1

ETABS Building Design Manual

www.civilax.com

Civilax.com

Page 2

ETABS Building Design Manual

Civilax.com

Fig 1.2-Plan view www.civilax.com

Page 3

ETABS Building Design Manual

Civilax.com

Fig 1.3-Vista height Civil Engineering Community | www.civilax.com

Page 4

ETABS Building Design Manual

1.2.

Civilax.com

Initial data

a) Structural Settings Has a regular shape in plan, to prevent the vertical geometric discontinuity or irregularity in resilient systems, the vertical structural elements (structural walls and columns), no change will be shaped section over the entire height of the building. Vertical accessibility elements such as stairs or elevators have been taken into account in the model. b) Structural System It was defined as a Reinforced Concrete Structural System Dual (porches + structural walls). c) Materials structural elements -Columns: Reinforced Concrete, fc = 210 Kg / cm2. -Beams: Reinforced Concrete, fc = 210 Kg / cm2. -Losas Solid: Reinforced Concrete, fc = 210 Kg / cm2. -Steel: Grade 60 fy = 4200 Kg / cm2. d) Overload Design -Entrepisos: 200 Kg / m2 -Azoteas: 100 Kg / m2. e) Dead Loads Finished floor concrete: 0.05 cm x 2000 Kg / m2 = 100 kg / m. Tabiqueria equivalent: 150 Kg / m. f) Dimensions of structural elements -Column 1 = 0.30 m x 0.30 m -Column 2 = 0.30 m x 0.30 m Civil Engineering Community | www.civilax.com

Page 5

ETABS Building Design Manual

Civilax.com

-Column 3 = 0.30 m x 0.30 m -Column 4 = 0.25 x 0.25 -column 5 x 0.25 = 0.35 -Beams 101 = 0.30 m x 0.50 m -Beams 102 = 0.25 m x 0.40 m Solid Slab -Thickness = 0.15 m -Thickness Structural Wall Plate or = 0.25 m

Civil Engineering Community | www.civilax.com

Page 6

ETABS Building Design Manual

Civilax.com

2) DEFINITIONS In this part of the manual the "Define" menu to create the various sections to use slab thicknesses and structural walls, materials, case response spectrum loads, load combinations studied. The Etabs starts, and access to the main program window will be taken.

Proceed to create a new model, we use "New_Model" or the key combination "Ctrl + N".

Then the dialog box "Model Initialization", which serve to generate and define the grid in three dimensions for use in the model drawing will be charged.

Civil Engineering Community | www.civilax.com

Page 7

ETABS Building Design Manual

Civilax.com

We chose the Use With Built- in Settings option in the Display SI Metric units choose the option to make the units of the International System of Units, and click on OK.

2.1. AXES AND LEVELS "D ime n sio Grid n s (Plan)" In the direction "X" and "Y" have eight nine axes respectively, these values are entered in "Number Line X Direction" and "Number Line Y Direction". The spacing in both directions we let in seven eight respectivamenet, then we can edit their respective distances. Then select "Custom Grid Spacing". "S t o r s D imen sion" The number of levels you specify in "Number of Stories" in our case six. In "Typical Story Height" entered the value of three, which is the height that occurs in

Civil Engineering Community | www.civilax.com

Page 8

ETABS Building Design Manual

Civilax.com

higher levels. In "Bottom Story Height" we write the value of the height of the first level. Then select "Custom Story data".

The next step is to edit the axes in the "X" addresses and "Y", or as we call the grid model. We click on "Edit Grid", to edit distances of the axes, which we will in the dialog "Define Grid Data". On the right side in "Displays Grid as" we have two options to edit the separations between axes. By default distances are presented cumulative (option "Ordinates"), but more convenient is to work with wheelbases, as we face in the plans, so select the "Spacing" option. We entered the wheelbases in the "X" addresses and "Y". With the various options for the axes, we can tell the program that we are hidden, its location is to the left or right or up or down, if we wish to be considered as secondary axes, and also the names of each axis. Once the changes we click on the OK button to accept the changes.

Civil Engineering Community | www.civilax.com

Page 9

ETABS Building Design Manual

Civilax.com

Heights levels by clicking the "Edit Story Data" button is edited. The correct values are entered and click on OK to accept the changes.

That level is selected with "YES" in the "Master Story" column means that the elements we draw level, copied or automatically erased in levels that have selected this level in the "Similar To" column. Returning to the "New Model Quick Templates" box, select the "Grid Only" button. The other options "Add Structural Objects" allow us to create automatic models for other structural systems. It is clicked, and the program will present the main screen drawing grid plan and 3D.

UNPRG

Page 10

ETABS Building Design Manual

Civilax.com

Close the Model Explorer window by clicking the X button, not be very useful in these first steps of modeling the building.

UNPRG

Page 11

ETABS Building Design Manual

Civilax.com

Configure the drives so that they are in those that seem easier to work with, besides being the most common when establishing the various properties and dimensions of materials and structural elements to use. We click on Units (bottom-right of the screen working part) and choose the option Consistent Units

Table of consistent units change the units as shown below.

2.2. Materials The default Etabs brings materials according to their design modules, you can configure other materials knowing their properties. To configure a material entered by the "Define / Materials Properties" menu. In the "Define Materials" box we click on the "Add New Material" button add as materials having a particular property such as resistance to compression of 210 Kg / cm2.

UNPRG

Page 12

ETABS Building Design Manual

Civilax.com

In the "Add New Material Property" window configure the options as shown in the picture below

The properties that need to be modified to set a new material for the model with which we work have the following properties:

UNPRG

Page 13

ETABS Building Design Manual

Civilax.com

Table Modify / Show Material Property Data Design we click and change the Specified Concrete Compressive Strengt, fc 2100 ton / m2, which is our strength of 210 kg / cm2.Hacemos click OK.

In material property window we click, so we keep our material. For material steel grade 60 msmos we follow the steps, which summarize the following images:

UNPRG

Page 14

ETABS Building Design Manual

Civilax.com

We click on OK and the material is stored.

UNPRG

Page 15

ETABS Building Design Manual

Civilax.com

2.3. Sections for columns and beams Once you have defined a new material, we proceed to define the sections that will be used in the model, such as columns and beams. The Etabs allows us to define these elements with objects "Frame". In the model we draw 3 types of columns, we will define the C1 column. We enter the "Define / Section Properties / Frame Sections" menu, once in the "Frame Properties" box on the "Click To" section, and click on Add New Properties.

In the Frame Shape Property Type window, go to Section Shape and choose the option box rectangular concrete.

We chose the option marked with red and we will automatically open the form to define a new rectangular section. Should choose as a material which we have

UNPRG

Page 16

ETABS Building Design Manual

Civilax.com

defined in the previous step, once introduced the dimensions of the C1 (0.30 mx 0.30 m) column, click on the Modify / Show button Rebar

When we have the box "Reinforcement Data" dialog, verify that "Design Type" "Column" is selected, the configuration of the reinforcement is rectangular ("Configuration of Reinforcement"), choosing a setting in a circular reinforcement option of stirrups is activated spiral, "Cover to Rebar Center" entered the value of the coating (in this Model 5 cm) in "Check / Design" we are asked whether you want that the program design us section or review us a given configuration. Once the changes we click on the button, to return to the previous dialog.

UNPRG

Page 17

ETABS Building Design Manual

Civilax.com

Now click on the button and we will have completed the creation of the C1 column. Similarly one proceeds with the creation of the columns C2 and C3. In the case of the beams, two types will be taken. The V101 beam will have a section 0.30 mx 0.50 m, and use it in the "X" direction; we will use the V102 beam in the direction "Y" and will have the dimensions 0.25 mx 0.40 m. To create the two types of sections for the beams we proceed similarly to how it did so with columns. The variation is that when you need to define the data and form of reinforcement, clicking on Modify / Show Rebar, in "Design Type" we must select "Beam", we see that the change to a design section and beam The table also changes. In "Concrete Cover to Rebar Center" entered the values of the coating, 6 cm. Clicking on, accept the change of type of design section.

UNPRG

Page 18

ETABS Building Design Manual

Civilax.com

See that when a beam is defined, the program assigns the reinforcing rods in the case of columns. Click again and have defined the V1 section. Similarly one proceeds with the V102 beam. When the 2 types of sections are defined, click on, to accept and exit the "Frame properies" box.

2.4. Section solid slab Define for flat slab with a section thickness of 0.15m. On the "Define / Section Properties / SlabSection" entered the Form menu to define the elements that will consist of three-dimensional finite element type Shell. In the "Slab Properties" box on the "Click to" section choose "Add New Property". In the properties box "Wall / Slab Property Data chose concrete material we have previously defined in the section" Modeling type "entered both" Shell-Thin. Clicking OK we have defined section used in the solid slab.

UNPRG

Page 19

ETABS Building Design Manual

Civilax.com

When the section is taken we click on OK to close the "Slab Properties" dialog and return to the main screen Etabs. 2.5. Section for structural walls Define structural wall for a section thickness of 0.25m. On the menu "Define / Section Properties / Wall Section" entered the form to define the elements that will consist of three-dimensional finite element type Shell. In the "Wall Properties" box on the "Click to" section choose "Add New Property". In the properties box "Wall / Slab Property Data chose concrete material we have previously defined in the section" Modeling type "entered both" Shell-Thin. Clicking OK we have defined section used in the solid slab.

When the section is taken we click on OK to close the "Wall Properties" dialog and return to the main screen Etabs.

UNPRG

Page 20

ETABS Building Design Manual

Civilax.com

3) DRAWING MODEL BUILDING The drawing of the building in ETABS can be varied due to the diversity of options and buttons offered by the program, which propose the following procedure below. 3.1. Drawing columns First of all go to one story button and change the option to like stories so that sections we draw will be made on every floor we have, with the exception of the base used to the foundation.

Let the Draw / Draw Beam / Colum / Brace Objects / Quick Draw colums menu.

The Properties of Object box, section COL 1 chose our property section.

UNPRG

Page 21

ETABS Building Design Manual

Civilax.com

To draw COL 1 section we will first work ETABS window (Plan View) and click on the node 8A and the program draw the COL 1 in the center of the node.

Perform the same procedure for the rest of columns 1, leaving the model follows.

UNPRG

Page 22

ETABS Building Design Manual

Civilax.com

Do the same procedure for the remaining columns of Table changing Properties of Object, in the Property section COL 2 section and then COL 3, being the model as follows.

UNPRG

Page 23

ETABS Building Design Manual

Civilax.com

To view the items drawn in 3D, go to Display Option Icon Set We change the colors of a View by Section Properties option, mark the options Extrude Extrude Frames and Shells, and we Apply, leaving the model as follows.

UNPRG

Page 24

ETABS Building Design Manual

Civilax.com

3.2. Drawing beams Let the Draw / Draw Beam / Colum / Brace Objects / Draw Beams / Colums / Brace menu

The Properties of Object box, section 101 VIG chose our property section.

UNPRG

Page 25

ETABS Building Design Manual

Civilax.com

To draw a section 101 VIG let the first window work ETABS (Plan View) and click on the node 8A and 8E then the node, so the program draw the VIG 101, taking as limits those two nodes.

We perform the same procedure for the rest of BEAMS 101, being the model as follows.

UNPRG

Page 26

ETABS Building Design Manual

Civilax.com

Do the same procedure for changing the other beams Properties of Object box in the property section 102 BEAM section, leaving the model follows.

3.3. Drawing slabs Let the Draw / Draw Floor / Wall Objects / Draw Rectangular Floor ¨

UNPRG

Page 27

ETABS Building Design Manual

Civilax.com

Properties of Object box, section 15 LOSA chose our property section.

To draw the slab section 15 we will first work ETABS window (Plan View) and click on the node 8A and then the 7E node, so the program draw the slab 15, taking as limits those two nodes.

Perform the same procedure for the other slab 15, leaving the model follows.

UNPRG

Page 28

ETABS Building Design Manual

Civilax.com

We added the 5th floor slab between the axes 32 and DF which border the structural walls of the elevator.

UNPRG

Page 29

ETABS Building Design Manual

Civilax.com

3.4. Drawing of structural walls Let the Draw / Draw Floor / Wall Objects / Draw menu Walls (Plan) ¨

The Properties of Object box, section 25 WALL chose our property section.

To draw the slab section 15 we will first work ETABS window (Plan View) and click on the node 8A and then the node 7A and the program draw the WALL 25, taking as limits those two nodes.

UNPRG

Page 30

ETABS Building Design Manual

Civilax.com

Perform the same procedure for the other 25 WALLS, leaving the model follows.

UNPRG

Page 31

ETABS Building Design Manual To see the overall result Drawing building modeling we go to icon

Civilax.com

Transparency

Toggle, we click and the building is shown as follows.

As a final part of the model drawing I select the beams that are on the walls of cut and eliminated, leaving as a result, the structure shown below.

UNPRG

Page 32

ETABS Building Design Manual

Civilax.com

4) RESTRICTIONS AND FINITE ELEMENT 4.1. Restriction mapping When you draw the columns, we see that in the Z = 0 level, the program automatically draws support in the bases, but you need to make changes to these supports. The supports on the base are commonly modeled as props wardrobes. To change the type of support you have to work with the support points with vertical elements in the base. All points are selected and through the "Assign / Joint / Restraints" menu assign the media type you want. In the "Assings Restraints" box you can select if you want to make restrictions on movement or rotation of the supports.

As we want to model supports with perfectly embedded hypothesis, simply select the six constraints.

UNPRG

Page 33

ETABS Building Design Manual

Civilax.com

We click on the button and we will have completed allocate support the model.

SUPPORT BUILT

UNPRG

Page 34

ETABS Building Design Manual

Civilax.com

4.2. Assigning Irises Trucks The model for concentrated loads in the mezzanine allows us to calculate assumption that all points on a given level have the same displacement. Then we assign rigid diaphragms model. The Etabs to assign rigid points mezzanine slabs or diaphragms. Slabs selected model and enter the "ASSIGNS / Shell Area / Diaphragms" menu. By default the program shows the "D1" and created which is a rigid diaphragm. We can add a different aperture for each level or use one type for the entire model.

We click on Apply and returning to the main screen we will present the mass centers where mass is concentrated for seismic calculation.

UNPRG

Page 35

ETABS Building Design Manual

Civilax.com

We continue with the same procedure to assign rigid diaphragms in the 5-story building modeled.

UNPRG

Page 36

ETABS Building Design Manual

Civilax.com

4.3. Assignment of Finite Element Mesh The finite element method is an approximate method for structural analysis, to smaller dimensions of the elements better accuracy. Can not recommend the size of these elements, since the process of going remallando into smaller overload the computer elements and takes longer to run. The calculation process is iterative in which you need to measure the error and convergence proposed values to reach these values it is assumed that the model has good accuracy, then we can not say if the elements are of a meter has a good approximation.  For slabs: We select all the tiles from the first to the fifth floor doing just click on them and we will assign / Shell / Auto Mesh Floor Options

Mesh Object Into activate the option and place a mesh elements 4 x 4, thus creating our mesh finite slab elements. Note that elements placed 4x4 heavy not to return the program and not suffer further lags when modeling the structure.

UNPRG

Page 37

ETABS Building Design Manual

Civilax.com

Then the program will give us the display mesh created.

UNPRG

Page 38

ETABS Building Design Manual

Civilax.com

 For structural walls: We select all the tiles from the first to the fifth floor doing just click on them and we will assign / Shell / Wall Auto Mesh Options

Mesh Object Into activate the option and place a mesh elements 4 x 4, thus creating our mesh finite slab elements. Note that elements placed 4x4 heavy not to return the program and not suffer further lags when modeling the structure.

UNPRG

Page 39

ETABS Building Design Manual

Civilax.com

Then the program will give us the display mesh created.

4.4. Assigning elements to structural walls Pier For visualization of the cutting forces in structural walls, shear walls have to be assigned as Pier elements. For this I select one of my shear walls and go to Shell / Pier Label menu, as shown below:

UNPRG

Page 40

ETABS Building Design Manual

Civilax.com

In the box that appears select the option P1, and give OK, being assigned our shear wall.

Do the same for the rest of our shear walls, obtaining the following dialog Pier elements of all our walls:

For cutting diagrams are displayed, columns confining walls should also be assigned as Pier elements, which perform the same procedure for allocation. For this I select one of my shear walls and go to the Frame / Pier Label menu and follow the steps above.

www.civilax.com Page 41

ETABS Building Design Manual

Civilax.com

5) LOADS OF GRAVITY, SEISMIC ANALYSIS STATIC AND DYNAMIC 5.1. Assigning Static Loads The loads own weight of structural elements that provide rigidity to the system, finishes, mobile partitions, overloads, as the design standards combined with factors majorization. It is the reason for different load cases are taken. To define the load cases entered by the "Define / Load Patterns" menu. By default the program defines two types of goods: "DEAD" where all loads from the structural elements that can be drawn on the Etabs, "LIVE" that will serve to overload will accrue.

In the "Define Load Patterns" table, we see that the load cases are organized types. The value must enter the "Self Weight Multiplier" column for the case "DEAD" is one, this indicates to the program in that case load weights of structural elements that can be drawn are entered, considering in For loads "LIVE" a value of one program in this case will deliver the weight of structural elements, is the reason why only a load case should be assigned a value of one (100% by weight of elements), otherwise we would be doubling the weight, unless for some reason or regulation is need to consider a combination of own weight in other load cases. In addition to considering loads, live loads added two more with the names of LIVE 1 and LIVE 2, for alternating loads on slabs and thus achieve maximum efforts.

www.civilax.com Page 42

ETABS Building Design Manual

Civilax.com

5.2. Static Seismic Analysis For the method of Equivalent Horizontal Forces we define four load cases as the eccentricity of the applied forces can be positive or negative, for each direction of analysis have two cases. Just as in cases of dead loads and overloads on rooftops, first entered a name the first call "SISMOXXPOS" in "Type" choose "SEISMIC" when choosing this type is a side load, we unlock the column "Lateral Auto Load" and select "User coeficients." Then click the Add New Load to add the event of an earthquake in the direction "X" with a positive eccentricity. We click on Modify Lateral Load to edit this load case. In the "User Defined Seismic Loading" box, we chose the "Direction and Eccentricity" section; in "Ecc. Ratio (. All DIAPH) verify that the value is 0.05 (5%) to calculate the eccentricity; in the "Factors" section under "Base Shear Coefficient, C" entered the peak value of the acceleration, which in our case is 0.2333g, the value of "Build Height Exp. K" we let one since the distribution of seismic forces will have a linear variation. We click on and we will have edited the first seismic cases for static analysis. The distribution of forces in the mezzanines and the value of "K" can be seen in the following figure:

The remaining three cases are performed in the same way, you should take into account the direction and eccentricity for each case and the value in "Base Shear Coefficient, C" of 0.2333g.

www.civilax.com Page 43

ETABS Building Design Manual

Civilax.com

The four cases for static analysis by equivalent forces would be as follows:

EARTHQUAKE

XX POS EARTHQUAKE XX NEG

EARTHQUAKE YY POS

EARTHQUAKE YY NEG

www.civilax.com Page 44

ETABS Building Design Manual

Civilax.com

We click on OK and our burdens have been created. 5.3. Load allocation In this model only distributed loads applied to slabs mezzanines are presented. The sum of the loads is indicated in the following table:

1st level 2nd level 3rd level 4th level 5th level

DEAD 250 kg / cm2 250 kg / cm2 250 kg / cm2 250 kg / cm2 100 kg / cm2

LIVE 200 kg / cm2 200 kg / cm2 200 kg / cm2 200 kg / cm2 100 kg / cm2

Select the slab fifth level, using the "Assign / Shell Load / Uniform" menu you can enter values for each load case. We enter the value of the dead load on the fifth level, the "Load Pattern Name" section of "Shell Asignament-Uniform Load" select "Dead" box, review the units and the "Uniform Load" section entered the value of 0.25 "Load" in "Direction" verify it "Gravity" so that loads are applied in the direction of gravity ("Z"). We click on OK and we will have introduced dead loads on the fifth level, in the same way the rest of loads in their cases are entered.

www.civilax.com Page 45

ETABS Building Design Manual

Civilax.com

The Etabs as entering charges go, allow us to display the value thereof.

For the fifth level, as you no longer have partitions on it, due to the architectural model, the dead load changes from 0.25 t / m2 to 0.10 t / m2.Por so select slabs fifth level in one story and follow the steps above to assign the load, except change in the load box value from 0.25 to 0.10, giving and taking click OK and all our dead loads on the structure.

www.civilax.com Page 46

ETABS Building Design Manual

Civilax.com

For live loads the same procedure explained to dead load is followed.

In the case of alternating loads, the slabs are selected grid layout and charges like the procedure for allocating dead loads are allocated by changing the load DEAD loads LIVE LIVE 1 and 2, respectively.

www.civilax.com Page 47

ETABS Building Design Manual

Civilax.com

Fig-selection for floor slabs grid layout

www.civilax.com Page 48

ETABS Building Design Manual

Civilax.com

Fig-1 charges LIVE assigned grid layout. The same procedure is performed for loads LIVE 2. 5.3. Calculation of the mass of the building for Static and Dynamic Analysis The Etabs makes the calculation of different load cases, but according to the rules Seismic Design, load cases with participation rates are taken. For NTE E-030, has the following requirements:

For the model consider 100% of the dead load ("DEAD and 25% of the live loads (" LIVE ")

www.civilax.com Page 49

ETABS Building Design Manual

Civilax.com

To assign these percentages for calculating the Etabs entered using the Define / Mass Source menu. In "dialog box choose the Define Mass Source Specified Load Patterns option and add the combination Structure weight = 100% + 25% DEAD LIVE From as follows:

We click OK and the program will already have calculated the weight of the building, which will serve to calculate static and dynamic seismic forces. 5.4. Dynamic seismic analysis Incorporating Spectrum Design strictly obeys the implementation of Article 18.2 . in the item b, which depends on several factors, such as shown in formula: = / = Is the area factor, which is found in Table No. 1 of the E.030. For purposes in this example, it was assumed that the building will be built in Lambayeque, then:

=. UNPRG

Page 50

ETABS Building Design Manual

Civilax.com

= Is the factor of use, depending on the category of the Building, in this case of type C, in accordance with Table No. 3 above = = The soil factor that has to do with the study of soils, according to local conditions set out in Table No. 2, was assumed for this example S3 soil type, therefore,

=. = The rate of reduction of seismic force, which depends on the structural system and building material, as most of the system is composed of walls, whereas analysis is a system STRUCTURAL WALLS start.

R=6

UNPRG

Page 51

ETABS Building Design Manual

Civilax.com

= The seismic amplification factor, which depends on the period of Structure and Soil. As this value depends on a time period T (s) and Spectrum Design is plotted versus time, then you can generate a table of values Sa / g - Time with Sa / g dependent on C, then Spectrum Design would be plotted as shown in the figure below, to the factors identified above: SPECTRUM Design- NTE E.030 Z U S Tp R ZUS / R

T 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 O n 2 eT h 4 5r e6 e7 8 9 10 UNPRG

0.4 One 1.4 0.9 6 0.08

Sa C 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.23333333 2.5 0.21 2.25 0.105 1,125 0.07 0.75 0.0525 0.5625 0.042 0.45 0.035 0.375 0.03 0.32142857 0.02625 0.28125 0.02333333 0.25 0.021 0.225 Page 52

ETABS Building Design Manual

Civilax.com

To enter this spectrum to ETABS must follow the following steps: 1. Copy and columns ZUCS T / R are such that together, as shown 2. Copy and paste this table into a notepad, and save the file.

3. In ETABS, follow the path shown in Figure 6-2, then in the window that opens, where it says ASCE7-10 deploy and find the option that says "From File", as in Figure 6- 3 to take the option to import the spectrum from the previously saved file.

4. Then we click on the Add New Function button, and the load spectrum window .txt file format giving you click the Browse button and load the file * .txt format as shown in Figure 6-4, giving finally click the Open button

UNPRG

Page 53

ETABS Building Design Manual

Civilax.com

5. Finally we see the graphic design Spectrum has been imported to the program, which should be displayed so as shown in Figure 6-5. After giving accept all OK.

ALLOCATION OF DYNAMIC SHEAR To determine the Dynamic Shear product of the spectral accelerations and mode shapes, modal and directional applying combinations of CQC and ABS. We follow the path shown in Figure and then the "Load Cases" window where the load cases that have generated as a result of charging patterns are defined above will open.

UNPRG

Page 54

ETABS Building Design Manual

Civilax.com

In this window we will generate Dynamic load cases of type Response Spectrum Analysis for each address.

UNPRG

Page 55

ETABS Building Design Manual

Civilax.com

EARTHQUAKE XX DIN

EARTHQUAKE YY DIN

Then, we accept each load case generated by the button, leaving cases of Static and Dynamic load.

UNPRG

Page 56

ETABS Building Design Manual

Civilax.com

+

5.5.

Defining Load Combinations

After having loaded the structure systems acting loads, load combinations must be performed in order to exercise the maximum effects on the structure, the following load combinations were used: EARTHQUAKE = SXX + 1.4D + 1.7L SYY + 1.25L + 1.25D EARTHQUAKE To define load combinations to be used, we will define / Load Combination

UNPRG

Page 57

ETABS Building Design Manual

Civilax.com

After the selected option will appear Combination Load follows combinations definition window, as shown below.

In this window you must click on Add New Combo, which show the window to generate the design load combinations as shown. First write the name of the combination. Finally, you must enter each of the terms forming the combination. Is exemplified the COMB1  NOTE: The combinations giving Reinforced Concrete E.060 standard are the linear and combinations earthquake and envelope design are the envelope type. Change those terms in the Load Combination Type box

The same procedure for all remaining combinations follow.

UNPRG

Page 58

ETABS Building Design Manual

Civilax.com

A combination is created apart to observe the weight of the building, which WEIGHT OF THE STRUCTURE is denominated. This will have the following data:

Also a combination that indicates the value of the modified floor of the building, which we call TRAVEL displacement was created. This will have the following data not forget that this combination is the ENVELOPE type:

The Scale value left 0.75R factor: 0.75 x 6 = 4.50 Taking all our combinations we click on OK and you're fully defined structure.

UNPRG

Page 59

ETABS Building Design Manual

Civilax.com

6) ANALYSIS AND REVIEW OF RESULTS So what was done in the previous items, it is necessary to prepare the model before running the calculation. In this part of the manual will indicate the steps and considerations for running the model. 6.1. Model analysis Before performing the analysis is necessary to check if any error in the model is present, entered by the Analyze / Check Model menu. And we mark all options, click OK and the program will check if an error (warning), if applicable tells us that needs correcting errors is presented.

As a next step we have run the model, click on the icon or through the Analyze / Run Analysis menu or also by medior the "F5" key. A dialog box is displayed where analysis is displayed. When the program finishes the scan, it will show in the deformed model window.

UNPRG

Page 60

ETABS Building Design Manual

Civilax.com

6.2. Displacements display To view the displacements let Display / Show Tables. In this table we will Analisys / Results / Displacements / Diaphragm Drifts / OK and windows below will be displayed.

UNPRG

Page 61

ETABS Building Design Manual

Civilax.com

The following table shows:

In the Load option Case / Load Comb choose the combination displacements and drifts floor observe corrected by the value 0.75R, which are shown below.

Compared with the value of the standard E.030 Earthquake Resistant Design, which says that the maximum drift floor is 0.007, so that our structure meets the allowable displacement and pass the design stage. By observing the displacements in the drift option, these are higher than the norm and therefore must be corrected structuring increasing the lengths of the shear walls or other structural elements.

UNPRG

Page 62

ETABS Building Design Manual

Civilax.com

To change this model to the following structure is proposed: Added walls in the stairwell and the column was changed to 0.40 x 0.40 m

The following displacement, the new structure will have:

UNPRG

Page 63

ETABS Building Design Manual

Civilax.com

Storey drifts complying with the requirements of the standard and you can design the structure. 6.3. Graphical display of axial, shear and moment To see diagrams internal forces of the structure we go to Display Frame icon

Load

Combination chose our Surround mix and then Component choose any option inner strength q wish to note: axial (compressive forces or tension), 2-2 shear (shear forces), at 3-3 (bending moments) .In Include choose the Frames option.

We click on OK, and the results will be displayed in any window (3d, plan or elevation) that we want.

Diagram axial forces

UNPRG

Page 64

ETABS Building Design Manual

Civilax.com

Diagrams axial forces

UNPRG

Page 65

ETABS Building Design Manual

Civilax.com

Shear forces diagram

Bending moment diagram To view more detail the forces in the elements, you must click right on any item and table displaying forces results in greater detail will be obtained.

UNPRG

Page 66

ETABS Building Design Manual

UNPRG

Civilax.com

Page 67

ETABS Building Design Manual

Civilax.com

7) DESIGN OF STRUCTURE 7.1. Definition of design codes Let the menu Design / Concrete Frame Design / View-Check Preferences, as shown in the picture:

We changed the factors 11 and 13 of the window, which are factors compressive strength and torsiion. Then we click on OK.

UNPRG

Page 68

ETABS Building Design Manual

Civilax.com

7.2. Selecting combinations of design We go to Design / Concrete Frame Design / Select Design Combinations menu, as shown in the picture:

In the window of Design Load Combination Selection I click on the SURROUND combination, which will be our combination of design. Then we click on and we will have chosen our combination of design. Finally we click Ok.

UNPRG

Page 69

ETABS Building Design Manual

Civilax.com

7.3. Calculation of amounts of reinforcement in structural elements Select the entire structure and go to Design / Concrete Frame Design / Start Design / Check menu, as shown in the picture:

The program displays the amounts of steel of all elements determined by the program. Seem small quantities because they are m2, so that Units change units ma cm, to obtain the correct values for the amounts design.

UNPRG

Page 70

ETABS Building Design Manual

Civilax.com

7.4. Design of columns with Section Designer Let's Define / Section Properties / Frame Section, as shown in the picture:

Then we click on Add New Property in the following table we click on Section Designer, to prune our column design

UNPRG

Page 70

ETABS Building Design Manual

Civilax.com

For the design of column 2, put the following data:

We click on Section Designer and spent the design itself of our column. We click on Draw Rectangle and then click in the center of coordinates.

UNPRG

Page 71

ETABS Building Design Manual

Civilax.com

We click on Reshape Object and then in the center of coordinates.

UNPRG

Page 72

ETABS Building Design Manual

Civilax.com

Assign the following our column, which are shown below. Then get a picture of our initial section.

UNPRG

Page 73

ETABS Building Design Manual

Civilax.com

We click on the indicated point and put the features of our modeling each of the bars of the drawn section.

UNPRG

Page 74

ETABS Building Design Manual

Civilax.com

Change the spacing of the steel bars so they can get 4 bars according to the design made for the column.

UNPRG

Page 75

ETABS Building Design Manual

Civilax.com

Change the type of the missing steel bar and get the complete design of the required column.

The same procedure for the other columns C1, C3, CL as min and then map each node to its respective column, according to the amount of steel required follows. UNPRG

Page 76

ETABS Building Design Manual

Civilax.com

7.5. Design of shear walls with Section Designer To observe the Piers, go to the menu / Other Assignments / Pier Assignments / Labels, elevations after that, the frames remain as follows:

Let's Design / Shear Wall Design / Select Design Combinations and select the envelope as combination of design:

UNPRG

Page 77

ETABS Building Design Manual

Civilax.com

Then wall design for the following procedure, abbreviated pictures, since very similar to the design of a column steps are followed.

UNPRG

Page 78

ETABS Building Design Manual

UNPRG

Civilax.com

Page 79

ETABS Building Design Manual

Civilax.com

Picture of the wall at the beginning of Section Designer

UNPRG

Page 80

ETABS Building Design Manual

Civilax.com

Picture of the wall after I have designed in the Section Designer.

UNPRG

Page 81

ETABS Building Design Manual

UNPRG

Civilax.com

Page 82

ETABS Building Design Manual

Civilax.com

After having made the design of the wall is passed to check AMOUNTS and check whether the wall is not sufficiently resistant wing action of applied loads on if it is not you happen to change the reinforcing steel. The same wall design for the remaining structure elements Piers performed is performed.

UNPRG

Page 83