Week 5 - WPBD vs Knex

Last week during our lab period the knex pieces were introduced. We got to play with them and build random structures and get ideas on how we were going to use them for our bridge. This was very useful because now we could build the models of our bridges using knex which is closer to real situations than West Point Bridge Design.
Now that we are using Knex the concept of actually building the bridge comes into play. The transition from designing and estimating the cost of a bridge in WPBD to using knex is a big one. The most important difference when the bridge is designed is that in WPBD the only design that can be altered is the one facing the front without considering the third dimension. When I started to use the knex that other surface came into play. Now the design has to be functional in all of the bridge's surfaces and not only two of which WPBD controls. One of the limitations that using knex has is that the member lengths cant be altered. There are only a limited amount of lengths that each member can measure, this decreases the possibilities of the different bridges that can be designed. Another limitation that the knex pieces have are the connecting joints. The joints that connect to make a 360 connector cant satisfy all cases. The maximum number of rods that can be connected to this type of connector is I believe 16, 8 in one plane and the other 8 in a plane that is perpendicular to the first one. This limits the connections when three planes are trying to intersect, this often happens when the bridge design includes an arch.