Within the model I intend to consider mainly the weight of each individual strut, the strain on it, and Young's Modulus of the material. The struts of the bridge will be connected by joints, these will move as forces are applied to them and through this process they will pull and push on the struts lengthening and shortening them and then recalculating for the new resulting forces. The relationship between the main sections of the model will be codified through an LSD specification of their interaction.
This structure to the modeling will also allow for both experimentation with the model by changing the effective materials each part is made of and the physical laws it obeys. It will also allow for the expansion of the model to include other types of materials as the struts will be considered to be delivering forces to a joint.
For the creation of the bridges themselves a point and click interface would be optimal for the model as it will allow for many different bridges to be input and then tested. The bridges will then be testable with a number of different loads in different distributions.