@investigatorr , Investigator Malayalam presenting new video about 7 wonders of silk road in this video we are discussing about Xerxes' Pontoon Bridges tombs.
The construction of Xerxes' bridge over the Hellespont
The bridging of the Hellespont by Xerxes was a unique achievement. How was it done? The Chorus of Elders in Aeschylus' Persians expressed their wonder at ‘the flax-bound raft’, and Herodotus described the construction of the two bridges, each with warships as pontoons, with cables well over a kilometre long, and with a roadway capable of carrying a huge army. Classical scholars have generally found these accounts inadequate and even inexplicable, especially in regard to the relationship between the pontoons and the cables. The Hellespont has strong currents which vary in their direction, turbulent and often stormy waters, and exposure to violent winds, blowing sometimes from the Black Sea and sometimes from the Mediterranean. How were the warships moored in order to face the currents and withstand the gales? Did the warships form a continuous platform, or was each ship free to move in response to weather conditions? What was the function of the enormous cables? How and where were they made? Did they bind the pontoons together? Did they carry the roadway? How were they fixed at the landward ends? This article attempts an answer to these questions through the collaboration of a classical scholar and a mechanical engineer.
The bridging of the Hellespont by Xerxes was a unique achievement. Herodotus' description of the two bridges' construction with warships as pontoons, and with long cables and a roadway is controversial as the Hellespont has strong currents that vary in direction and force. However, the design of the bridges was within the capacity of the contemporary engineers. The cables formed the basis of the roadway of wooden planking and provided continuity and elasticity in the gaps between pontoons. The pontoon bridges, fixed with very long anchors, carried the entire weight of cables, roadway and traffic.
Surely ancient peoples must have looked longingly at unreachable shores on the other side of rivers and wished for bridges to carry them there. Wishes alone couldn't build those bridges, but war could.
Most early floating bridges were built for the purposes of war. The Chinese, Romans, Greeks, Mongols and other peoples all used versions of pontoon bridges to move soldiers and equipment, usually across rivers too deep to ford.
The most primitive floating bridges were wooden boats placed in rows with planks laid across them to support foot traffic, horses and wheeled carts. At each shore these bridges were secured, often with ropes, to keep them from drifting with the current or wind.
One of the most storied ancient floating bridges was created at the behest of the Persian king Xerxes. Xerxes set out to conquer Greece in 481 B.C., but first, his huge army had to cross the Hellespont, a strait about 4,409 feet (1.3 km) wide.
Xerxes commanded his men to build a floating bridge, but a violent storm subsequently destroyed their work. To show his anger toward the sea, Xerxes told his men to symbolically whip the water 300 times, and he also had leg shackles thrown into the sea. He punished the engineers of the failed bridge by beheading them.
A second bridge was built, and nearly 400 ships were used to keep its surface afloat. The boats were all tied together with heavy flaxen and papyrus ropes and weighted with heavy anchors to hold them in place, and there was an opening left so that small vessels navigating the strait could still pass the bridge.
Logs were used for the bridge's surface, and these were topped with brush and soil. And there were barriers on each side so that horses (and perhaps men) wouldn't be spooked by walking so close to their potential watery ends. This one survived, letting hundreds of thousands of soldiers pass over the strait. Ultimately, this army attacked and captured Athens.
Many wars since then have seen floating bridges in action, including the American Civil War and both World Wars. They continue to be vital for campaigns that must cross bodies of water to engage (or run away from) enemies.
Modern pontoon bridges are extremely portable and can often ride on a semi-truck trailer. They usually combine an inflatable underbelly that's topped with a metal structure that supports large vehicles and men.
Not all pontoon bridges are built for warfare. Keep reading, and you'll see how more permanent ones are constructed for more peaceful ends.
22 янв 2023
