### Iconic Road Bridge Design Optimization

Optimization is always a complex task, because involves design criteria and iterative decisions over the same problem until some condition is met. The optimization process involves a series of constraints related to costs, fabrication and aesthetics. The correct use of mathematics (Linear algebra, geometry, arithmetic, etc) in the right time is essential to converge in a successful result instead of fall in a infinite loop. The result is measurable with high precision and it needs to be quantifiable in order to transform data into information (plans and documentation).

Working at IDOM in 2013, I had the chance to work in a facade design-optimization for the Abi Bakr Road Bridge. The project was designed and developed 100% using programming (Rhinoscript). The design and development was a collective effort between architectural and engineering departments at IDOM Barcelona.

Design is an abstract process of organization that involves composition and evaluation. A good design is a subtle well balance of the elements in the system to organize. In this post I will not go through the design process but discuss about the optimization process.

An optimization process, needs to be described as a series quantifiable steps. Because is necessary to evaluate every step in the process and also the possibility to evaluate any adjacent element in the process. For example the cumulative gap tolerance among all panels. An optimization process also needs a target or stop condition which is essential to determine the path to set up the steps. for this project the target was to minimize the number of different facade panels in order to find the wright balance between design and rational budget.

Pictures from construction and design can be seen trough the web of this interesting company:

Ianofer Construct

The Optimization Process it was divided in three main steps:

## Step 1

### UNDERSTAND THE GEOMETRY AND DESIGN

Print all different angles from the existent design. Because the facade works as a wrapper of the structure and it was defined by 3 curves.

## Step 2

### REDUCE THE NUMBER OF DIFFERENT ANGLES BUT KEEP AT THE SAME TIME THE ORIGINAL DESIGN

The bridge is not symmetric in terms of elevation, therefore the angle of the structures varies from one structural frame to another. Therefore the facade performs as a double curvature surface. A subroutine was created to round the angles and redraw the existent profile again, with the smallest visual difference. At the end of the step we obtain a smooth curve composed by no more than 15 angles to wrap the structure.

## Step 3

### EVALUATE STEP 2 AND CHECK DISTANCE TO STRUCTURE

Check each curve segment is under the structural distance tolerance (dt) is 200 mm <= dt <= 500 mm. Some curves are deleted and replaced by equal segments in order to reduce the number of angles. At the end of the process we obtain a smooth curve composed by only 11 angles. In almost each case the angle change each 3 modules, which implies simple clues to mount and fabricate. The result is expressed in a diagram of angles as a phenotype of the design.

## Example videos of the the process

Envelope Generation:

The optimization process is documented trough scripting.

Pattern Generation:

The Patterns was designed based in a series of *points attractors*. In order to determine the intensity, size and points area influence, it was used an equation which is often used to describe stocks and markets in business disciplines.

Facade Documentation:

Programming was also used to unfold the pieces assign names and prepare the plans.