Scope: -
Parametric modeling of concrete of structural elements (beams, columns and slabs) where the parameters are the member properties of these elements and the sectional and material properties were kept constant. Since we will have same dimensions of beam and column, we can incorporate formwork which can be reused over and over again instead of plywood. The same formwork can be used in different projects, reducing the cost of formwork in a project and wastage.
Goal: -
As different structural properties are required at different seismic zones. Buildings need to be designed in a way that their natural frequency does not resonate with the frequency of any seismic event of the region. So, the goal of this assignment is to provide better alternatives for different seismic zones.
Parameters
Some parameters were established to achieve the goal. Parameters and along with initial values are listed below.
| Parameter | Value |
| Floor Height | 4 meters |
| Number of Floors | 4 Floors |
| Total Length | 56 meters |
| Span between Grids (in L) | 8 meters |
High Performance Criteria
To find the rigidity of the building, natural frequency of a building’s variables is kept as the high-performance criteria. However, some design related performance criteria are also established as there are some requirements by the architect and the user.
Beam and column design are based on ACI code 318-11 and research conducted. Beam is 400mm x 800mm and column is 600mm x 760mm. [1] [2]
| High Performance Criteria – Structural | Value | High Performance Criteria – Design | Value |
| Axial Rigidity of Column | 4.65 * 10^6 | Clear Height (m) | 2.2 |
| Flexural Rigidity of Beam | 48 * 10^3 | Clear Span (m) | 7.4 |
Axial and Flexural rigidity of this structure are comparatively high. [4] So, this design of beam and column members are rigid can be used in seismic zone 2-B which is also backed by research conducted.
Methodology: -
From the input values for these functions, high performance criteria are being studied in this model.
Alternative 1
For the first alternative, the span was reduced from 8m to 6m. Other parameters were not changed. On the basis of high-performance criteria (structural) it is more rigid. The carpet area of the building has been reduced or the aspect ratio has been reduced. We can see that by ratio of clear height by clear span of this alternative and comparing it with original values.
This model can be used on seismic zone 3 based on the aspect ratio required for it.
| High Performance Criteria – Structural | Value | High Performance Criteria – Design | Value |
| Axial Rigidity of Column | 4.65 * 10^6 | Clear Height (m) | 2.2 |
| Flexural Rigidity of Beam | 85.3 * 10^3 | Clear Span (m) | 5.4 |
Alternative 2
In the original model, parameter changed was the height per floor of the building. As previously, clear height of the building was reasonably small for commercial use. For this alternative, the height was increased to 5m from 3m. [3] The axial rigidity of columns has decreased but within limits for seismic zone 2-A. Although, the building can be made more flexible based on the flexural rigidity.
| High Performance Criteria – Structural | Value | High Performance Criteria – Design | Value |
| Axial Rigidity of Column | 2.79 * 10^6 | Clear Height (m) | 4.2 |
| Flexural Rigidity of Beam | 48 * 10^3 | Clear Span (m) | 7.4 |
Alternative 3
For this alternative, I tried to check the values of high-performance criteria for flexibility limit of the building. Number of floors were increased to 7, span between grids was changed to 10m and height of the floors was changed to 3m. All based from the research conducted and ACI / PCA notes 318-08. The aspect ratio is high and the carpet area is also large. Axial and flexural rigidity values are low. By adding floors, the mass has also increased which would mean that natural frequency of the building is low. Making this model ideal for seismic zone 1.
| High Performance Criteria – Structural | Value | High Performance Criteria – Design | Value |
| Axial Rigidity of Column | 3.48 * 10^6 | Clear Height (m) | 3.2 |
| Flexural Rigidity of Beam | 30.7 * 10^3 | Clear Span (m) | 9.4 |
References
ACI Code and PCA Notes 318-08
Comparative study on design of steel structures and RCC frame structures based on column span https://www.sciencedirect.com/science/article/pii/S2214785321033113 [1]
Design of Rectangular Reinforced Concrete Beam https://theconstructor.org/tips/rectangular-reinforced-concrete-beam-design/7472/#google_vignette [2]
Seismic Analysis of Regular & Vertical Geometric https://www.semanticscholar.org/paper/Seismic-Analysis-of-Regular-%26-Vertical-Geometric-Rana-Raheem/8a010be38be3e87b84705eb719cfd19b3ed9d81a 3 [3]
Analysis of Trusses, Beams, and Frames https://www.sciencedirect.com/science/article/pii/B9780128117682000092 4 [4]