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• Zabihullah Safi

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ETABS এপ্রিল ০৬, ২০১৭

ETABS 2013/2015 Steps: Step-01: Define Design Code and units Step-02: Define Grid & Story Data. Edit all stories data Step-03: Define Material Properties for Concrete, Rebar, and Masonry etc. Step-04: Define Section Properties of Beams, Columns, Slab, Stair, Walls, Mat etc. Step-05: Define Static Loads pattern, Load cases & Load Combination Step-06: Draw Model Step-07: Assign Gravity Loads to Floors, Beams, Stairs, Water Tanks Slab, Mat, Ramp Step-08: Define Diaphragm Step-09: Assign Support Step-10: Define Mass Source Step-11: Messing of Shells and Frames Step-12: Define and assign Pier & Spandrel level for all walls Step-13: Define Property Modifiers of Frames (beams and columns) and Stiffness Modifiers of Shells (slab & walls) A. Slab: •

Bending m1 1 Modifier

= 0.25

•

Bending m2 2 Modifier

= 0.25

•

Bending m1 2 Modifier

= 0.25

•

Others value

= 1.00

B. Column: •

Torsional Constant

= 1.00

•

Moment of inertia about2

= 0.70

•

Moment of inertia about3

= 0.70

•

Others value

= 1.00

C. Beam: •

Torsional Constant

= 0.01

•

Moment of inertia about 2

= 0.35

•

Moment of inertia about 3

= 0.35

•

Others value

= 1.00

D. Wall: •

Bending m1 1 Modifier

= 0.35

•

Bending m2 2 Modifier

= 0.35

•

Bending m3 3 Modifier

= 0.35

•

Others value

= 1.00

Step-14: Assign Auto Edge Constraints Step-15: Define Frame-Shell sway properties Step-16: Check for model Step-17: Run Analysis of the model Step-18: Design of the Concrete Frame Sections Step-19: Design of the Shear Walls Step-20: Design of Mat Step-21: Detailing of the Reinforcement

(i) (ii)

ETABS 2013/2015 Required Information: Curved Floor Plan. Beam-Column Layout Plan.

(iii)

Materials Properties: fc’ = 3000 psi fy = 60000 psi

Wc = 140 pcf (for Light) Wc = 150 pcf (for Stone Cheep)

(iv) (v) (vi)

Slab Type = Edge Supported Column/Beam = Rect. Foundation Type = If Soil is Good = Single Footing If Soil is not Good = Single Footing + Piling (vii) No of Story = 15 Story No Basement. (viii) Building Type = Residential. (ix) LL = 50 psf. (Only for High Rise) FF = 25 psf. (For all floors). (x) LL = (100 psf for stair) for Residential = (150 psf for stair) for Commercial.

Starting Project Model: Step-1: Define Code Click on this menu respectively: File>New Model> Use Built-in Settings with: >Concrete Design Code: ACI 315-11 > OK.

Step-2: Define Grid & Story Slab. o Simple Story Data > Number of Stories >15 Typical Story Height > 10’ (Without Ground Floor) Bottom Story Height > 12’ (For Ground Floor) o Uniform Grid Spacing> Number of Grid Lines in X direction >6 Number of Grid Lines in Y direction >4 Spacing of Grids in X direction >10 Spacing of Grids in Y direction >20 o Add Structural Object > Grid Only > OK. Note: Change Display Color o Options > Graphics Colors >Display > 1. Column- Red 2. Beam – Blue 3. Springs (Support) – Yellow 4. Floor – Green 5. Background – White 6. Walls – Black 7. Opening – Ash 8. Grid Lines – First Color> OK. Step-3: Define Materials Properties A Concrete (fc’) Define > Material Properties... > Add New Material Property > Material Type > Concrete > Grade >f’c 3000 psi > OK. Material Property Data >

General Data > Material Name > CON 3.0 > OK. B Rebar (fy) Add New Material Property > Material Type > Rebar >Standard ASTM A615 > Grade > Grade 60> OK. Material Property Data > General Data >Material Name > Rebar 60.0> OK.

Step-4: Define Section Properties A Beam (FB) Define >Section Properties >Frame Sections... > Filter Properties List>Concrete Rect. > Click to > Add New Property >Concrete > Rect. Shape > Note: B1 = 12x14 B2 = 14x16 B3 = 14x18 B4 = 16x20

B5 = 16x22 B6 = 16x24 General Data >Property Name >B1 = 12x14> Material > CON 3.0 > Section Dimensions >Depth = 14’ > Width = 12’> Modify/Show Rebar >M3 Design Only (Beam) > Rebar Material >Longitudinal Bars >Rebar 60 > Confinements Bars (Ties) >Rebar 60 > Cover to Longitudinal Rebar Group Centroid > Top Bars > 2.5” > Bottom Bars > 2.5” > OK > OK >

B Beam (GB) Add New Property > Note: GB1 = 12x12 GB2 = 12x16 GB3 = 14x16 GB4 = 14x16 Note: Cover to Longitudinal Rebar Group Centroid. Top Bars = 3” Bottom Bars = 3” Note: Top & Bottom Bars will be 3” for Great Beam Only. On the other case is same.

C Column > Add New Property >Concrete > Rect. Shape > Note: C1 = 12x16 C2 = 14x18 C3 = 18x22

C4 = 18x20 C5 = 20x24 C6 = 22x26 C7 = 24x28 C8 = 24x30 General Data > Property Name > C1 = 12x16 > Material > CON 3.0 > Section Dimensions >Depth = 16’ > Width = 12’ > Modify/Show Rebar > P-M2-M3 Design > Rebar Material > Longitudinal Bars > Rebar 60 > Confinements Bars (Ties) > Rebar 60 >OK > OK. D Slab Define > Section Properties > Slab Sections... > Slab Properties > Click To > Add New Property >

Slab Property Data > General Data > Property Name >S 5.0 > Slab Material > CON 3.0 > Modeling type >Shell-Thin > Note: Shell-Thin – EDGE Support Slab Shell-Thick – Flat Plate, Flat Slab and Wall Membrane – Curved Slab/Dom Property Data > Type > Slab > Thickness >5” >OK > OK.

Preset P-Delta Options Click the Define menu > Preset P-Delta Options command to access the Preset P-Delta Options form. Use the form to apply the options to all linear load cases unless specified otherwise in the P-Delta/Nonlinear Stiffness area of the Load Case Data - Linear Static and Linear Direct Integration History forms. Set the P-Delta analysis parameters by making selections in the following areas of the Preset P-Delta Options form. Automation Method: An initial P-Delta analysis in this program considers the P-Delta effect of a single loaded state upon the structure. Specify the load using one of the following options: ▪

None option. Use this option to not consider P-Delta effects, including removing previously considered effects.

▪

Non-Iterative -- Based on Mass option. The load is computed automatically from the mass at each level as a story-by-story load upon the structure. This approach is approximate, but does not require an iterative solution. This method essentially treats the building as a simplified stick model to consider the P-Delta effect. It is much faster than the iterative method. It does not capture local buckling as well as the iterative method. This method works best if the model has a single diaphragm at each floor level, although it also works for other cases as well. The reason we provide this method is to allow consideration of P-Delta in cases for which gravity loads have not been specified in the model. If gravity loads have been specified in the model, in general, we recommend use of the Iterative Based on Loads option.

▪

Iterative -- Based on Loads option. The load case is computed from a specified combination of static load patterns. This is called the P-Delta load case. For example, the load case may be the sum of a dead load case plus a fraction of a live load case. This approach requires an iterative solution to determine the P-Delta effect upon the structure. This method considers the P-Delta effect on an element-by-element basis. It captures local buckling effects better than the noniterative method. We recommend the use of this iterative method in all cases except those for which no gravity load is specified in the model. ▪ o

Relative Convergence Tolerance: This area is active if the Iterative -- Based on Loads option is selected in the Automation Method area of the form. See Iterative Solution, Convergence Tolerance for more information.

o

Iterative P-Delta Load Case: This area is active if the Iterative -- Based on Loads option is selected in the Automation Method area of the form. Specify the single load case from a combination of load patterns to be used for the initial P-Delta analysis of the structure. As an example, assume that the building code requires the following load combinations to be considered for design: (1) 1.4 dead load (2) 1.2 dead load + 1.6 live load

(3) 1.2 dead load + 0.5 live load + 1.3 wind load (4) 1.2 dead load + 0.5 live load - 1.3 wind load (5) 0.9 dead load + 1.3 wind load (6) 0.9 dead load - 1.3 wind load For this case, the P-Delta effect associated with the overall sway of the structure can usually be accounted for, conservatively, by specifying the P-Delta load case to be 1.2 times dead load plus 0.5 times live load. This will accurately account for this effect in load combinations 3 and 4 above, and will conservatively account for this effect in load combinations 5 and 6. This P-Delta effect is not generally important in load combinations 1 and 2 because there is no lateral load. It is also possible to accurately account for the P-Delta effect associated with the deformation of the members between their ends in the ETABS analysis, but we do not recommend that you do this. Instead, we recommend that you account for this effect using factors in your design. The ETABS design postprocessors assume that this has occurred and includes those factors, where appropriate, in the design. To account for the P-Delta effect associated with the deformation of the members between their ends in the ETABS analysis, first break up all of the columns into at least two objects between story levels. Then run each of the six load cases above separately with a different P-Delta load combination for each. Again, it is recommended that this effect be included using factors in your design, as is performed in the ETABS design postprocessors.