Process Observations - Hudson

While working with the West Point Bridge Design software, there are a few things I have noticed.
1) The bridge design will only show one truck going across one way. This is a fairly unrealistic scenario for a two lane bridge. Chances are, at some point there are going to be multiple cars going multiple directions at different places on the bridge and it seems like this is one area where the WPBD software isn't exactly the best.
The software also doesn't take into account weather forces. Constant wind, rain, ice, sun, or a mixture of these forces can be the downfall of a bridge. Frequent freezing and thawing can create micro-cracks in the structure and wind could cause the structure to bend in unusual ways.
2) The bridge cost does not take a lot of other factors into consideration. While joints and bars are important, what is more important is the cost of labor, foundation, decking, paving, nuts and bolts... there are a lot more considerations when building a bridge than just the joints and bars.
The bridge cost also seems to be outdated. While theoretically I can build a bridge for $250,000, that's probably not the case if I was to actually set about building the bridge I designed.
3) The bridge can't be modeled over time. Bars and beams are going to get weaker over time and if the bridge is painted frequently that's added weight and stress on the bridge that isn't being taken into consideration. If the bridge just barely passes to begin with, over time the structure might become weak enough that it collapses.

With this in mind, I still think the WPBD software is excellent for beginning bridge designs and our uses. It's not overly complicated, but it still has several different options for most choices. It helps people get a basic understanding of what works and what doesn't work and a ballpark range of what the bridge might cost.

WPBD Process Observations - Lester

The West Point Bridge Designer is an extremely useful designing program. The interface is user-friendly and results from the stress tests are simple. Colors for stress and strain in load test simulations are straightforward and convenient for seeing where problems could occur. Real-world conditions and restrictions are applied to the bridge, such as a limit to the amount of materials that can be used and a limit of different member types, shapes, and lengths. As with all engineering situations, there is not one correct answer. Many different designs can be structurally sound, as the program demonstrates. Load testing complies to the AASHTO truck loading code. Adhering to Codes is essential in working with structures like bridges. The program acts similarly to other professional structural analysis programs that are used in the field.

However, the program is not completely accurate. Costs are far more complicated than beam size and material type; costs include roadways, the 3-dimensional structure, concrete and other materials, support beams, and even labor. There are changes in weather and wind patterns that are not factored in that could affect a structure. A prime example of this is the Tacoma Narrows bridge, which eventually failed because of constant high winds. Load testing is also not completely accurate. The only load tests available in WPBD is a two-lane highway with a single truck moving in one direction. In real bridges, traffic goes both ways and is not limited to one spot at a time. This information is crucial to designing a real bridge. Bridges that work perfectly in WPBD tests may quickly fail realistic load tests. Quite a few other factors are not accounted for in the WPBD program, including fatigue on materials over time or natural disasters like earthquakes or snow storms.

The program emphasizes that it is an introduction to the bridge design process and is not necessarily the best program for the technical details in a design. As far as a design program goes, the WPBD is highly accurate and does perform many essential tests and functions.

-Belinda Lester 

Process Observations-Durkin

WPBD is an educational engineering program that can teach a student a lot about bridges but falls short in a number of areas when it comes to real world bridge design.  For example the program does not consider secondary members, three-dimensional stability of the bridge, or the many types of member failure. WPBD also does not consider how the bridge will hold up under environmental stresses or how it will effect its surrounding environment. This is important because the ground that the bridge is built on needs to be strong enough to support that bridge and the bridge need to be strong enough to with stand erosion that the ground and water will be under it. WPBD also does not take into consideration how the bridge would fair in the case of a natural disaster.  Leaving out these environmental factors makes it important to see WPBD as an educational program alone. The program also only takes things like cost and some measures of stability into consideration leaving out aesthetics and the amount that the bridge bends as criterion. WPBD also falls short when it comes to the type and distribution of weight that it considers when it comes to traffic. It only considers two types of traffic and traffic in only one direction when testing the bridge.  Also during testing the lateral position of the weight of traffic on the bridge is not considered. The program also does not use the exact cost of materials or consider the cost of labor to build the bridge as these can change with the economy and other factors.

~Jacquelyn Durkin