Bridges

Man is a sociable creature, but more so in regard to the mind than to the body.
She likes lonely walks, but she hates being alone in her opinions. (George Santayana)

Anfang hen one talks about dedicated bridges in connection with beam traffic systems, the only principal difference from ordinary beamsections is that the supporting poles are usually farther apart, creating a wider span than what the beams could normally handle. Apart from this difference, the choice will usually be between letting the beam traffic travel on a bridge of its own, or being attached to an existing bridge, being used for other kinds of traffic. This is not a technical page; we just want to show some examples of how beam bridges could be constructed.

hen one talks about dedicated bridges in connection with beam traffic systems, the only principal difference from ordinary beamsections is that the supporting poles are usually farther apart, creating a wider span than what the beams could normally handle.		Apart from this difference, the choice will usually be between letting the beam traffic travel on a bridge of its own, or being attached to an existing bridge, being used for other kinds of traffic. This is not a technical page; we just want to show some examples of how beam bridges could be constructed.

Mobile illustration of beam bridge for suspended traffic

Figure 1.

hown above and below is a dedicated bridge, carrying only beam traffic (figure 1). The suspension technique lends itself well to spanning long distances; the cables in this illustration help considerably in carrying the weight of the beams. Thanks to them, the span could be as long as for existing brdges, and even the smallest beams could carry the heaviest vehicles. Although this bridge is only intended for beam traffic, one could put a walkway atop a two-beam bridge, as shown to the right. It is worth noting the big advantage it would be in earthquake-prone cities if huge concrete bridges for motor vehicles over rooftops and other streets could be replaced with beam bridges. Instead of clearing away tons of debris from a collapsed concrete bridge, the relatively modest rubble left behind by the beams could be cleared in a couple of days. Figure 2.

hown above and below is a dedicated bridge, carrying only beam traffic (figure 1). The suspension technique lends itself well to spanning long distances; the cables in this illustration help considerably in carrying the weight of the beams. Thanks to them, the span could be as long as for existing brdges, and even the smallest beams could carry the heaviest vehicles. Although this bridge is only intended for beam traffic, one could put a walkway atop a two-beam bridge, as shown to the right.

It is worth noting the big advantage it would be in earthquake-prone cities if huge concrete bridges for motor vehicles over rooftops and other streets could be replaced with beam bridges. Instead of clearing away tons of debris from a collapsed concrete bridge, the relatively modest rubble left behind by the beams could be cleared in a couple of days.

Figure 2.

Beam bridge with pedestrian walkway on top

Beam bridge of suspension type

Figure 3.

Shown below are 3 examples of
beams attached to existing bridges:

The beams are fastened to transverse supporting beams, placed at regular intervals of about 30 meters, above the road (Figure 5)
The beams are attached underneath the road (Figure 6)
The beams run beside the road, for instance under the walkways (Figure 7)

Figure 4. ==>

Four beams over a regular bridge

Figure 5.

Figure 6.

Figure 7.

sing the alternative with transverse supporting beams that carry the beam traffic above the original bridge has an added value when it comes to bridges that opens now and then to allow big ships to pass through underneath. If the beams are high enough, they would not have to open along with the bridge. Possibly, the beam traffic has to make a temporary pause if a particularly tall ship passes through. Drawbridges might pose a problem, insofar as the beams might be in the way of the mobile section as it goes up. This could be solved by using ordinary poles for beamsupport, and lead the beams along the sides of the bridge.	Figure 8.

sing the alternative with transverse supporting beams that carry the beam traffic above the original bridge has an added value when it comes to bridges that opens now and then to allow big ships to pass through underneath. If the beams are high enough, they would not have to open along with the bridge. Possibly, the beam traffic has to make a temporary pause if a particularly tall ship passes through.

Drawbridges might pose a problem, insofar as the beams might be in the way of the mobile section as it goes up. This could be solved by using ordinary poles for beamsupport, and lead the beams along the sides of the bridge.

Figure 8.

One interesting challenge would be to mount beams on top of floating bridges like this one (figure 9). The beams would need joints that are flexible enough to withstand the largest anticipated waves that could occur at the intended building site.

Beams on a floating highway bridge
Figure 9.

One interesting challenge would be to mount beams on top of floating bridges like this one (figure 9). The beams would need joints that are flexible enough to withstand the largest anticipated waves that could occur at the intended building site.	Figure 9.

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