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bernard wrote:

nxtscholar wrote:So someone correct me if I'm wrong (I'm a biomathematics major, although one with a strong interest in engineering), but I had a sudden pop into my mind that I'm rather curious about.

Does this year's rules with regards to the test support actually affect division B more and thus pose a bigger challenge to them than division C? Like, by nature of the rules, division C bridges are longer than division B bridges because of a longer mandated span. Consequently, the test support creates a larger angle of inclination for division B bridges than division C bridges. I'm going along the lines of simple geometry. For division C, it's a "rise" of 5 cm to a "run" of 45 cm. For division B, it's about a rise of 5 cm to run of 35 cm.

Thus, doesn't this create a larger change in the direction of forces and stress for division B than division C compared to last year? In other words, don't division B teams have more to change in their designs than division C with regards to changing truss designs, thickness of members, etc.?

I emphasize, however, that regardless of division, the test support doesn't seem to be changing the problem that much. But the question I ask is does division B technically have more to deal with than division C in terms of change?

I don't have an answer at this hour but the different spans brings up another question: does the "tilt" have more of an effect for a large angle change involving a short span or a smaller angle involving a longer span? Does span or angle affect the challenge more? I would guess the span's added challenge dramatically increases with greater spans, with greater angles adding more challenge but with less of a magnitude. Just a guess coming from a sleepy person though.

nxtscholar wrote:

bernard wrote:

nxtscholar wrote:So someone correct me if I'm wrong (I'm a biomathematics major, although one with a strong interest in engineering), but I had a sudden pop into my mind that I'm rather curious about.

Does this year's rules with regards to the test support actually affect division B more and thus pose a bigger challenge to them than division C? Like, by nature of the rules, division C bridges are longer than division B bridges because of a longer mandated span. Consequently, the test support creates a larger angle of inclination for division B bridges than division C bridges. I'm going along the lines of simple geometry. For division C, it's a "rise" of 5 cm to a "run" of 45 cm. For division B, it's about a rise of 5 cm to run of 35 cm.

Thus, doesn't this create a larger change in the direction of forces and stress for division B than division C compared to last year? In other words, don't division B teams have more to change in their designs than division C with regards to changing truss designs, thickness of members, etc.?

I emphasize, however, that regardless of division, the test support doesn't seem to be changing the problem that much. But the question I ask is does division B technically have more to deal with than division C in terms of change?

I don't have an answer at this hour but the different spans brings up another question: does the "tilt" have more of an effect for a large angle change involving a short span or a smaller angle involving a longer span? Does span or angle affect the challenge more? I would guess the span's added challenge dramatically increases with greater spans, with greater angles adding more challenge but with less of a magnitude. Just a guess coming from a sleepy person though.

Oh that is true...it's possible a change in angle impacts longer span bridges faster than shorter span bridges. But I don't take statics, so... :P

nxtscholar wrote:So someone correct me if I'm wrong (I'm a biomathematics major, although one with a strong interest in engineering), but I had a sudden pop into my mind that I'm rather curious about.

Does this year's rules with regards to the test support actually affect division B more and thus pose a bigger challenge to them than division C? Like, by nature of the rules, division C bridges are longer than division B bridges because of a longer mandated span. Consequently, the test support creates a larger angle of inclination for division B bridges than division C bridges. I'm going along the lines of simple geometry. For division C, it's a "rise" of 5 cm to a "run" of 45 cm. For division B, it's about a rise of 5 cm to run of 35 cm.

Thus, doesn't this create a larger change in the direction of forces and stress for division B than division C compared to last year? In other words, don't division B teams have more to change in their designs than division C with regards to changing truss designs, thickness of members, etc.?

I emphasize, however, that regardless of division, the test support doesn't seem to be changing the problem that much. But the question I ask is does division B technically have more to deal with than division C in terms of change?

dholdgreve wrote:
I see where you are coming from, and yes, as the span decreases, the angle of the bridge increases... depending on how you design your bridge... In theory, you could design an elevated bridge, then chop off the elevated legs on one side... In that case, there is no angle due to the elevation change.

dholdgreve wrote:

nxtscholar wrote:So someone correct me if I'm wrong (I'm a biomathematics major, although one with a strong interest in engineering), but I had a sudden pop into my mind that I'm rather curious about.

Does this year's rules with regards to the test support actually affect division B more and thus pose a bigger challenge to them than division C? Like, by nature of the rules, division C bridges are longer than division B bridges because of a longer mandated span. Consequently, the test support creates a larger angle of inclination for division B bridges than division C bridges. I'm going along the lines of simple geometry. For division C, it's a "rise" of 5 cm to a "run" of 45 cm. For division B, it's about a rise of 5 cm to run of 35 cm.

Thus, doesn't this create a larger change in the direction of forces and stress for division B than division C compared to last year? In other words, don't division B teams have more to change in their designs than division C with regards to changing truss designs, thickness of members, etc.?

I emphasize, however, that regardless of division, the test support doesn't seem to be changing the problem that much. But the question I ask is does division B technically have more to deal with than division C in terms of change?

I see where you are coming from, and yes, as the span decreases, the angle of the bridge increases... depending on how you design your bridge... In theory, you could design an elevated bridge, then chop off the elevated legs on one side... In that case, there is no angle due to the elevation change.

embokim wrote:Does anybody have anything to say about a trapezoid shaped bridge with no joints around the actual contact point of the loading block and the bridge?
Last minute ideas, thank you. :mrgreen:

Mr_Pep_Band wrote:Hi all, I am new to this forum but competed in Science Olympiad in high school, and have run the Bridge Bruilding/Boomilever/Towers event the last 5 years at North Dakota State competition whilst in college at NDSU. Every year I have facilitated State competition, I try to build 2-3 bridges for fun and to better understand the event and what it takes to win. This year they threw a curve ball at us with the unsymmetrical loading abutments.

Am I correct in how this is laid out in CAD for the C Division with the 5 cm tall abutment on one side and then the max 2 cm height on the other side?

C Layout.PNG

Mr_Pep_Band wrote:Hi all, I am new to this forum but competed in Science Olympiad in high school, and have run the Bridge Bruilding/Boomilever/Towers event the last 5 years at North Dakota State competition whilst in college at NDSU. Every year I have facilitated State competition, I try to build 2-3 bridges for fun and to better understand the event and what it takes to win. This year they threw a curve ball at us with the unsymmetrical loading abutments.

Am I correct in how this is laid out in CAD for the C Division with the 5 cm tall abutment on one side and then the max 2 cm height on the other side?

C Layout.PNG