Ice Breaker Tool for parametric tower form design
Overview:
This ice breaker tool is designed to keep in mind to come with the preliminary design decision for parametric tower form. During the preliminary design decision, the developer, architect, and structure designer usuallyplay the key role. This tool offers various input and output parameters which are helpful to all three in their initial decision-making process. By simple try and error with various input parameters or using generative design tool developer, architect, and structure designer can quickly come up with very few design options out of many possibilities available.
Introductory Video:
Input Parameters:
Related to architect;
- Tower Geometry - Building Ht., Base Radius, Angle of twist
- Shaper related - number of sides of a polygon
- Space planning - story Ht.
- Lighting - Solar potential of the building
Related to Developer
- Construction cost / floor area
- Construction cost / roof area
- Construction cost / facade area
- Energy-related - Solar Potential of the building
Related to structure designer
- Based on usage - weight of the building / floor area
- Seismic related - Sms and S1 of the site
Output Parameters:
Related to architect;
- Gross floor area
- Gross volume
- Solar insolation
These outputs are helpful for an architect to start with space allocation and design the use of various area.
Related to Developer
- Total material cost
- Cost / insolation
This helps developers to get tentative cash flow and benefits of the project.
Related to structure designer
- Axial load of the building
- Base shear
- Overturning moment
This is useful for a structural engineer to think about the structural system and foundation choice for the building as it is also important to maintain the project’s overall cost.
Application:
This ice-breaker tool is extremely helpful in the industry in the kick-off meetings between architects, developers, and structure designers to set important parameters and initial design related decisions. Using this tool user can potentially create infinite different tower form and optimized their design based on location and primary goals in the mind.
Limitation:
As this tool particular type of tower form where it can create variation based on tower usage and goals. Let’s say this tool is not useful to design low-rise or industrial shades kind of structures.
Dynamo Logic is as below.
Inputs
The dynamo graph includes all sorts of input, including tower geometry, story ht, tower ht, solar input parameters, various cost of construction and structural parameters like floor wt, and seismic acceleration of the area.
Limitation: There can be more input parameters related to tower geometry. Here I am using mathematical formulas to get those parameters like radius of the tower at mid-height and at top height. Here to limit the number of inputs and to avoid the unreasonable geometry of the tower, those parameters not kept as user input.
Geometry creation and identifying various surfaces of the tower
In the first step, I am defining the geometrical shape at the base, mid and top height of the tower. Then lofting the surface to those geometrical curve. After lofting the surface, I am identifying the various surfaces like roof, wall and ground surfaces.
Creating mass floor area and solar potential of the building
In the next step, I am dividing tower ht. into floors based on story height set by the user and creating mass floors.
Also, as shown in the below image based on solar inputs by the user, I am calculating solar potential of the building.
Calculating structural parameter
Time period, Two-period response spectra and forces at the base
step - 1 Estimating the natural time period of the structure.
To estimate the natural time period of the structure, I am using ASCE 7 equation to calculate the natural time period estimate based on total height of the tower. Assuming this kind of building form is constructed using a shear core wall building in the center.
step - 2 Creating two-period response spectra and calculate the seismic acceleration:
This is also done using ASCE 7 procedure to calculate seismic acceleration from two period response spectra.
Two period response spectra is calculated based on user input value Sms and S1.
Step - 3 Calculating forces
Axial load, Base shear, and the overturning moment is calculated. It is assumed that lateral load distribution in the structure is inverted triangle which is a good estimate of the lateral loading.
Limitation: All this structural parameters are approximate to get an overall idea during initial decision making process.
Math before final output
Now in the previous step we have all the surfaces identified, loads value, and solar potential values are calculated. So, using math here, I am preparing various parameters important for output.
i.e. Sum up floor area at a different level to get total area, gross volume, calculating material cost, cost/insolation, assigning color to the surfaces of the building etc.
Outputs
As discussed in the introduction outputs helpful to developers, architect and structure designers are calculated here.
All the costs are in $, area in SF. When these results are obtained it is very useful to use dynamo player to see everything and quickly make small change to get the desired output.
Generative Design Tool:
This same dynamo graph can be used to create a generative design study for parametric tower form and get the combination of input parameters for the optimized design option.
It is recommended to use only a few input parameters and freeze other parameters as the tool offers many input and output parameters. In the decision-making process as we move forward we need to fix each one of the parameters. Strategic use of the tool can be really helpful in initial design-related decision-making.
Above is one example shown to find the optimized design. Here, I am minimizing material cost, maximizing material cost and minimizing base shear on the structure. As you can see as height of the building increases seismic acc. decreases but wt. of the building also increases. So, base shear might increase or decrease. By using generative design tool as we can see size of the marking is showing base shear values. Along with low cost, more solar potential we can also get less base shear for the chosen tower form.
Limitation: To get the best result from a generative design tool, it is recommended to optimize or set a few parameters as the variable then choose all at once. As this tool is designed considering in mind to use in a variety of projects and different goals. So, it has many inputs and output parameters.