A1-Hudson

1) My bridge design goal was to make the most cost effective bridge possible. My bridge is the shape it is because I found this shape to be the most cost effective and it seemed to bear the weight of the bridge better than my first designs.

2)

Image 1: 2D view of the bridge in Drawing Board mode. 

3)

Image 2: View of the bridge in Test mode with a truck in the center.

4)

Image 3: Load test results numbers 1 through 38.

Image 4: Load test results numbers 6 through 43.

5)

Image 6: Bridge in Test mode with trusses above the bridge.

During the designing process, I went from attempting to build a bridge where the weight of the bridge is supported by trusses that are over the bridge (Image 5) to a bridge where the weight was supported by trusses under the bridge (Image 1 and Image 2). I found this to be more cost effective and less prone to errors. I started out this way because most of the bridges I have ever seen have the weight supported from above rather than below, but while designing my own bridge I realized there were far too many problems with how the weight is distributed while the truck is crossing the bridge. 

6) My current bridge cost, as seen in Image 1, is 393,202 dollars and 44 cents. I think this could be brought down to under 350,000 dollars at least, possibly even under 300,000 dollars with further time and knowledge by eliminating bars and joints. 

7) While building this bridge I learned that sometimes designs that seem good on paper do not actually work out in real life. My bridge would seem stable but when the truck drove onto the bridge it would buckle in unexpected places, like the very middle of the road. I also learned that there are some support bars that are fundamental to whether the bridge will work or not and other bars that, while they seem important, can be taken out with no major impact to the strength and durability of the bridge.

A1-Durkin

Dennis H. Mahan Memorial Bridge
Project ID: 00001A-
Designed By:
# Material Type Cross Section Size (mm) Length (m) Compression Force Compression Strength Compression Status Tension Force Tension Strength Tension Status
1 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 684.28 4655.00 OK
2 CS Solid Bar 140x140 3.61 671.57 2900.89 OK 0.00 4655.00 OK
3 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 467.64 4655.00 OK
4 CS Solid Bar 140x140 3.61 450.40 2900.89 OK 0.00 4655.00 OK
5 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 393.02 4655.00 OK
6 CS Solid Bar 140x140 3.61 375.78 2900.89 OK 0.00 4655.00 OK
7 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 304.45 4655.00 OK
8 CS Solid Bar 140x140 3.61 287.21 2900.89 OK 0.00 4655.00 OK
9 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 199.87 4655.00 OK
10 CS Solid Bar 140x140 3.61 182.63 2900.89 OK 0.00 4655.00 OK
11 CS Solid Bar 140x140 3.61 49.70 2900.89 OK 95.17 4655.00 OK
12 CS Solid Bar 140x140 3.61 77.93 2900.89 OK 66.94 4655.00 OK
13 CS Solid Bar 140x140 3.61 154.43 2900.89 OK 0.00 4655.00 OK
14 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 171.67 4655.00 OK
15 CS Solid Bar 140x140 3.61 258.94 2900.89 OK 0.00 4655.00 OK
16 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 276.18 4655.00 OK
17 CS Solid Bar 140x140 3.61 346.97 2900.89 OK 0.00 4655.00 OK
18 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 364.21 4655.00 OK
19 CS Solid Bar 140x140 3.61 422.18 2900.89 OK 0.00 4655.00 OK
20 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 439.42 4655.00 OK
21 CS Solid Bar 140x140 3.61 650.53 2900.89 OK 0.00 4655.00 OK
22 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 663.24 4655.00 OK
23 CS Solid Bar 140x140 4.00 0.00 2633.62 OK 752.09 4655.00 OK
24 CS Solid Bar 140x140 4.00 0.00 2633.62 OK 1231.45 4655.00 OK
25 CS Solid Bar 140x140 4.00 0.00 2633.62 OK 1611.73 4655.00 OK
26 CS Solid Bar 140x140 4.00 0.00 2633.62 OK 1877.15 4655.00 OK
27 CS Solid Bar 140x140 4.00 0.00 2633.62 OK 2008.20 4655.00 OK
28 CS Solid Bar 140x140 4.00 0.00 2633.62 OK 2004.55 4655.00 OK
29 CS Solid Bar 140x140 4.00 0.00 2633.62 OK 1866.21 4655.00 OK
30 CS Solid Bar 140x140 4.00 0.00 2633.62 OK 1593.46 4655.00 OK
31 CS Solid Bar 140x140 4.00 0.00 2633.62 OK 1206.67 4655.00 OK
32 CS Solid Bar 140x140 4.00 0.00 2633.62 OK 728.75 4655.00 OK
33 CS Solid Bar 140x140 5.39 491.54 1732.39 OK 0.00 4655.00 OK
34 CS Solid Bar 140x140 5.39 0.00 1732.39 OK 318.03 4655.00 OK
35 CS Solid Bar 140x140 5.39 598.41 1732.39 OK 0.00 4655.00 OK
36 CS Solid Bar 140x140 5.39 0.00 1732.39 OK 762.83 4655.00 OK
37 CS Solid Bar 140x140 5.39 499.18 1732.39 OK 0.00 4655.00 OK
38 CS Solid Bar 140x140 5.39 0.00 1732.39 OK 637.31 4655.00 OK
39 CS Solid Bar 140x140 5.39 387.70 1732.39 OK 0.00 4655.00 OK
40 CS Solid Bar 140x140 5.39 0.00 1732.39 OK 486.29 4655.00 OK
41 CS Solid Bar 140x140 5.39 251.32 1732.39 OK 0.00 4655.00 OK
42 CS Solid Bar 140x140 5.39 0.00 1732.39 OK 330.06 4655.00 OK
43 CS Solid Bar 140x140 5.39 95.18 1732.39 OK 132.78 4655.00 OK
44 CS Solid Bar 140x140 5.39 89.73 1732.39 OK 173.72 4655.00 OK
45 CS Solid Bar 140x140 5.39 0.00 1732.39 OK 289.06 4655.00 OK
46 CS Solid Bar 140x140 5.39 245.94 1732.39 OK 17.60 4655.00 OK
47 CS Solid Bar 140x140 5.39 0.00 1732.39 OK 445.34 4655.00 OK
48 CS Solid Bar 140x140 5.39 383.00 1732.39 OK 0.00 4655.00 OK
49 CS Solid Bar 140x140 5.39 0.00 1732.39 OK 596.50 4655.00 OK
50 CS Solid Bar 140x140 5.39 496.79 1732.39 OK 0.00 4655.00 OK
51 CS Solid Bar 140x140 5.39 0.00 1732.39 OK 723.23 4655.00 OK
52 CS Solid Bar 140x140 5.39 600.45 1732.39 OK 0.00 4655.00 OK
53 CS Solid Bar 140x140 5.39 0.00 1732.39 OK 305.21 4655.00 OK
54 CS Solid Bar 140x140 5.39 478.87 1732.39 OK 0.00 4655.00 OK
55 CS Solid Bar 140x140 4.00 234.50 2633.62 OK 0.00 4655.00 OK
56 CS Solid Bar 140x140 4.00 421.01 2633.62 OK 0.00 4655.00 OK
57 CS Solid Bar 140x140 4.00 419.34 2633.62 OK 0.00 4655.00 OK
58 CS Solid Bar 140x140 4.00 457.78 2633.62 OK 0.00 4655.00 OK
59 CS Solid Bar 140x140 4.00 487.46 2633.62 OK 0.00 4655.00 OK
60 CS Solid Bar 140x140 4.00 488.39 2633.62 OK 0.00 4655.00 OK
61 CS Solid Bar 140x140 4.00 460.53 2633.62 OK 0.00 4655.00 OK
62 CS Solid Bar 140x140 4.00 423.59 2633.62 OK 0.00 4655.00 OK
63 CS Solid Bar 140x140 4.00 425.90 2633.62 OK 0.00 4655.00 OK
64 CS Solid Bar 140x140 4.00 242.37 2633.62 OK 0.00 4655.00 OK
65 CS Solid Bar 140x140 3.61 210.26 2900.89 OK 0.00 4655.00 OK
66 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 429.42 4655.00 OK
67 CS Solid Bar 140x140 3.61 451.36 2900.89 OK 0.00 4655.00 OK
68 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 434.12 4655.00 OK
69 CS Solid Bar 140x140 3.61 302.36 2900.89 OK 0.00 4655.00 OK
70 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 285.12 4655.00 OK
71 CS Solid Bar 140x140 3.61 197.14 2900.89 OK 0.00 4655.00 OK
72 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 179.90 4655.00 OK
73 CS Solid Bar 140x140 3.61 114.10 2900.89 OK 13.61 4655.00 OK
74 CS Solid Bar 140x140 3.61 30.85 2900.89 OK 96.86 4655.00 OK
75 CS Solid Bar 140x140 3.61 31.27 2900.89 OK 96.34 4655.00 OK
76 CS Solid Bar 140x140 3.61 113.57 2900.89 OK 14.03 4655.00 OK
77 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 179.27 4655.00 OK
78 CS Solid Bar 140x140 3.61 196.51 2900.89 OK 0.00 4655.00 OK
79 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 283.79 4655.00 OK
80 CS Solid Bar 140x140 3.61 301.03 2900.89 OK 0.00 4655.00 OK
81 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 430.79 4655.00 OK
82 CS Solid Bar 140x140 3.61 448.03 2900.89 OK 0.00 4655.00 OK
83 CS Solid Bar 140x140 3.61 0.00 2900.89 OK 422.27 4655.00 OK
84 CS Solid Bar 140x140 3.61 209.00 2900.89 OK 0.00 4655.00 OK
85 CS Solid Bar 140x140 4.00 611.63 2633.62 OK 0.00 4655.00 OK
86 CS Solid Bar 140x140 4.00 1077.31 2633.62 OK 0.00 4655.00 OK
87 CS Solid Bar 140x140 4.00 1362.86 2633.62 OK 0.00 4655.00 OK
88 CS Solid Bar 140x140 4.00 1517.60 2633.62 OK 0.00 4655.00 OK
89 CS Solid Bar 140x140 4.00 1566.25 2633.62 OK 0.00 4655.00 OK
90 CS Solid Bar 140x140 4.00 1509.14 2633.62 OK 0.00 4655.00 OK
91 CS Solid Bar 140x140 4.00 1357.12 2633.62 OK 0.00 4655.00 OK
92 CS Solid Bar 140x140 4.00 1077.42 2633.62 OK 0.00 4655.00 OK
93 CS Solid Bar 140x140 4.00 618.34 2633.62 OK 0.00 4655.00 OK
94 CS Solid Bar 140x140 7.81 256.46 820.46 OK 0.00 4655.00 OK
95 CS Solid Bar 140x140 7.81 255.64 820.46 OK 0.00 4655.00 OK
96 CS Solid Bar 140x140 2.00 41.62 3876.74 OK 0.00 4655.00 OK
97 CS Solid Bar 140x140 5.00 587.08 1970.68 OK 0.00 4655.00 OK
98 CS Solid Bar 140x140 2.00 40.38 3876.74 OK 0.00 4655.00 OK
99 CS Solid Bar 140x140 5.00 592.88 1970.68 OK 0.00 4655.00 OK
100 CS Solid Bar 140x140 6.40 0.00 1220.68 OK 477.56 4655.00 OK
101 CS Solid Bar 140x140 6.40 0.00 1220.68 OK 481.60 4655.00 OK
102 CS Solid Bar 140x140 5.00 329.39 1970.68 OK 0.00 4655.00 OK
103 CS Solid Bar 140x140 5.00 332.44 1970.68 OK 0.00 4655.00 OK

         












 My goal for the design of this bridge was to design a bridge that is both stable and inexpensive.  I went through multiple trials before deciding on this design.  Originally I tried adding X’s instead of triangles however that seemed to add little to no stability while greatly increasing the cost. I began with a simple single level, above the road bridge design but found this to be very unstable throughout the structure. I then added extra cross beams at the ends of the bridge; this made the bridge better connected to the ground.   This fixed the initial brake that occurred during the test but still left the center of the bridge very weak.  After adding an upper layer to the single level design the bridge became more stable but was still very strained toward the center.  I then added support below which made the bridge better able to support the truck as it drove across.  Adding the layer below also seemed to help distribute the weight of the truck more evenly as there was no longer one or two points on the bridge that were under great strain at any time. Also keeping the beams of the lower layer short helped keep costs low.  I chose to stick with the original beams as opposed to switching to tubes as each time a test was done with tubes instead of beams the bridge lost stability.  This loss of stability occurred regardless of where the tube replaced the beam showing that the weight is evenly distributed.  The cut in cost that using the tubes would achieve was not worth the lack of stability they would cause. Overall the cost of the bridge came to $605,811.49.

            By using the Westpoint Bridge Designer program I learned more about stability as well as how to use features such as how to use the Compression Force/Strength Analysis to better determine which areas need more support.  I also learned about the general structure necessary to make a strong and cost efficient bridge. I found that straight lines are incredibly unstable and that although very stable X’s are not very cost efficient. I learned that symmetry was a key characteristic to a strong structure, as one side being weaker than the other would nearly always lead to a brake in the bridge. It was important to be patient during this process and to be constantly testing as each added or taken away beam could make a significant difference.

     In the week to come our group will discuss the different features of our final designs.  We will than compare and contrast the bridges to see what needs to be modified and what should be included in our final group design.  We will try and find the most cost efficient and stable properties of each bridge.

~Jacquelyn Durkin

A1 - Lester

     My goal for this design was to create the most stable bridge possible. After finding designs that were sturdy, I worked on making them less expensive to build. I went through many trials, testing various shapes like X's, backwards and forwards V's, and single or double level trusses. I began with trusses build below the road, but switched to above the road support. There was no significant difference between above and below supported trusses except the beams had a tendency to overstretch on the bottom while they overcompressed on the top. An X structure bridge, which is what I call a bridge that has crossed beams instead of stand-alone triangles as support, was my first design. Although it is very stable, it costs more to build because there are double the amount of beams needed as compared to a simple triangle structure. The equilateral triangle V's on a slope was the most stable of all my trials, according to the Compression Force/Strength Analysis column in the load test results report. The angled slope of the bridge as it goes from the beginning to the middle cuts costs, since the beams are more compact and, therefore, cost less money (since beam are priced by size). Tubes are included in the most structurally sound locations to cut costs as well. Using tubes in a few places cut the cost of this bridge by almost $100,000. This bridge costs $620,984.96 altogether.
     I learned a lot about the Westpoint Bridge Designer program, like shortcuts and stress test features. I got a feel for what a correctly build bridge should look like. Symmetry and simplicity were both extremely important factors in keeping the bridge stable while limiting building materials to keep costs low. I also learned that designing a stable bridge is not nearly as easy as I'd thought. Shapes that seem stable actually collapse at unexpected places, like a horizontal support beam in the first half of the bridge, or a vertical beam in the center. Also, despite my partial skepticism, I found that simple triangles are in fact the strongest support.
     Next week, our group will compare our final designs and discuss which we want to continue modifying and what features can be taken from each design to make our bridge the most stable and cost efficient.

Belinda Lester