Extreme forces
极大的力
The North Atlantic is a stormy place. While our bridge would manage to avoid the fastest-moving parts of the Gulf Stream current, it would still be subjected to powerful wind and wave forces.
北大西洋风暴频发，也许我们的乐高大桥能够避开墨西哥湾流中快速移动的那部分，但它仍然会受到强风和大浪的冲击。
How strong could we make our bridge?
我们的大桥能造得多结实？
Thanks to a researcher at the University of Southern Queensland named Tristan Lostroh, we have some data on the tensile strength of certain Lego joints. Their conclusion, like the BBC 8217;s, is that Lego bricks are surprisingly tough.
好在有南昆士兰大学的研究人员特里斯坦•洛斯塔奇，我们能够获取某些种类乐高连接件的抗拉强度。和英国广播公司得出的结果相似，他们得出的结论也是乐高积木非常结实。
The optimal design would use long, thin plates overlapped with each other:
最佳的设计是把又长又薄的盘片互相重叠放在一起：
This design would be pretty strong-the tensile strength would be comparable to concrete-but not nearly strong enough. The wind, waves, and current would push the center of the bridge sideways, creating tremendous tension in the bridge.
这样的设计结构强度非常高——抗拉强度和混凝土有得一比——但还是远远不够用。大风、海浪和洋流会把大桥的中部往一个方向推，在桥身中产生出极大的拉力。
The traditional way to deal with this situation would be to anchor the bridge to the ground so it can 8217;t drift too far to one side. If we allow ourselves to use cables in addition to the Lego bricks,10 we could conceivably tether this massive contraption to the sea floor.11
解决这个问题的传统方法是把桥身锚定在地面上，这样桥体就不会往一个方向漂出太远的距离。如果我们还允许用绳索来建造乐高大桥，10我们就可以用绳索把巨大的桥身锚定在海床上。11
But the problems don 8217;t end there. A 5-meter bridge might be able to support a vehicle on a placid pond, but our bridge needs to be large enough to stay above water when waves are breaking over it. Typical wave heights on the open ocean could be several meters, so we need the deck of our bridge to be floating at least, say, 4 meters above the water.
但问题还没解决呢。一座5米宽的桥或许可以在平静的小池塘里浮起一辆汽车，但我们的乐高大桥需要在大风大浪的情况下仍然保持位于大浪上方。开阔海面上普通的浪高可达数米，因而我们需要让桥面浮在离水面至少4米的地方。
We can make our structure more buoyant by adding air sacs and hollows, but we also need to make it wider-otherwise it will tip over. This means we have to add more anchors, with floats on those anchors to keep them from sinking. The floats create more drag, which puts more stress on the cables and pushes our structure downward, requiring more floats on the structure . . .
我们可以通过增加气囊和空心腔体来增加整体的浮力，但这样一来我们需要加宽桥面，否则它就会翻转倾覆。这意味着我们需要动用更多的锚，锚上还要绑上浮筒以防止沉下去。增加的浮筒会增大阻力，会在绳索中产生更大的应力，把整个桥体往下拉，这样一来我们又需要更多的浮筒……
Sea floor
海床
If we want to build our bridge down to the sea floor, we 8217;ll have a few problems. We wouldn 8217;t be able to keep the air sacs open under the pressure, so the structure would have to support its own weight. To handle the pressure from the ocean currents, we 8217;d have to make it wider. In the end, we 8217;d effectively be building a causeway.
如果我们打算把大桥建造在海床上，那么会面临许多问题。在巨大的压强下，气囊完全无法张开，因而整个结构必须要承载自身的重量。要解决洋流冲击带来的问题，我们需要把桥造得更宽。于是最后我们相当于造了一条铺道出来。
As a side effect, our bridge would halt the North Atlantic Ocean circulation. According to climate scientists, this is “probably bad.”12
这样的一个副作用是北大西洋洋流将会被阻断，气候科学家表示由此引起的后果“很有可能是很糟糕的”。12
Furthermore, the bridge would cross the mid-Atlantic ridge. The Atlantic sea floor is spreading outward from a seam down the middle, at a rate-in Lego units-of one stud every 112 days. We would have to build in expansion joints, or drive out to the middle every so often and add a bunch of bricks.
此外，我们的大桥还会穿过大西洋中脊上方。大西洋海床正在从中间的一条裂缝向两边延伸，速度大约是每112天移动1块乐高积木的距离。因而我们需要在桥身上设置伸缩缝，或者频繁地去大洋中间添加几块积木。