Structural Project using: Autocad, Etabs, Safe, S-concrete and Excel Softwares

 INTRODUCTION

Any structure in the world begins with an architectural plan of the elevation, plans and 3D views drawn by an architect, followed by structural calculations and checks and design by a structural or civil engineer.

In this project, we will see the general steps used by a civil engineer to design a reinforced concrete residential building in Lebanon, using Autocad, Etabs, Safe, S-concrete and Excel Softwares.

Figure 1: Elevation

Figure 2: Basement Plan

Figure 3: Ground Floor Plan

It begins with architectural elevation (Fig. 1) and plans of the building (Figures 2 and 3), that the architectural engineer has drawn, by making assumptions for the column sections and places, as well as the shear walls distribution and thicknesses.

Your role as a structural or a civil engineer is to check if the column sections are good to retain the building, and if the shear walls are well distributed. You also have to find the reinforcement in all the structural elements: columns, shear walls, retaining walls, beams, slabs, stairs and foundation.

Figure 4: Architectural Plan Details

In the “Figure 4”, we have:

·        11 pink columns
·        3 pink shear walls
·        Blue doors
·        Light blue windows
·        Yellow stairs
·        Wight curtain walls
·        Green dimensions
·        Red opening

ETABS SOFTWARE

First of all, delete all the non-structural elements (windows, doors…) and draw the model on “ETABS Software” as you can see in “Figure 5”.

Figure 5: ETABS model

The next step is to define and add all the loads (except the self-weight as it will be calculated by the software):
·     Live load
·        Super imposed Dead Load (including the hourdis blocks loads)
·        Wind load
·        Seismic load (in x and y direction, positive and negative, with and without drift)
·        Soil pressure load

EXCEL SHEET

Before defining the loads combinations, open the “Excel Sheet” to begin the analysis check of your model, to see if it is stable or not and to see if you have to use the dynamic analysis or not “Figure 6”.

Check the center of mass and rigidity, the diaphragm classification, the story drift in X and Y, the wind displacement, the accidental torsion in X and Y, the mass and stiffness irregularity, P-delta effect and finally the scaling of dynamic.

In our case, we used the dynamic analysis, and the semi-rigid diaphragm as a conclusion from the excel analysis check.

Figure 6: Excel analysis check

You can now continue the ETABS calculations, and perform the design of the structural elements.

After structural calculation, some of the columns drawn by the architect were modified as the 2 columns in the middle top of the figure 4, and the section of other columns have been changed based on “ETABS” columns design results. But make sure not to modify the place of the columns to not change the architectural distribution of the rooms.

The column that is in the middle bottom of the shear walls in the “Figure 4” was also replaced with a horizontal long shear wall, because the shear wall design using “ETABS” software was not acceptable before this modification (Figure 7).

Figure 7: The plan after modification

SAFE SOFTWARE

The next step is to export each floor alone to “SAFE” software to check the log term and short term deflection for the slabs and beams, and to find the needed reinforcement for the slabs (Figure 8) and footings. The slab thickness taken in this project was 25 cm, and it was a hourdis slab type for all the floors.

Figure 8: Basement floor design using "SAFE" software

Draw the ribbed slab on AutoCAD and distribute the hourdis between the ribs (Figure 9).

Figure 9: Basement hourdis slab

S-CONCRETE SOFTWARE

After designing the structural elements, export the loads of the beams, columns and shear walls to “S-concrete” software and find the reinforcement distribution of these elements (Figure 10) based on ACI 318-11 code.

Figure 10: Column reinforcement using "S-concrete" software

You can then export the reinforcement to AutoCAD, and modify them.

You can also skip the S-concrete step, if you know well the code requirements and you can draw correctly the reinforcements by yourself.

AUTOCAD SOFTWARE

Now, draw all the columns sections (Figure 11) and make a table on AutoCAD that summarize the columns results for each story (Figure 12).

Figure 11: Columns reinforcement in Basement floor

Figure 12: Columns reinforcement table

For each floor, draw using AutoCAD (Figure 13):

·        A plan of the columns and their axis
·        A drawing and a table for the column reinforcements
·        A plan of the slab reinforcement
·        A plan of the beams
·        A plan of the shear walls
·        A drawing and a table for the beams reinforcements

Draw also:

·        A plan showing the stairs reinforcement

·        The retaining walls reinforcements in plan and elevation

·        A plan for footing dimensions and another one for footing reinforcements

In this project, raft footing of 60 cm thickness is used because we have a basement floor.

Figure 13: AutoCAD Basement Plans

An ETABS, Safe or S-Concrete file can be easily exported to AutoCAD and modified there.

You can also draw the model on Revit Software to perform a 3D view for all the elements!