https://www.youtube.com/watch?v=ebY2q-4sYSU
https://www.youtube.com/watch?v=f8illUOlHzo

T h e oldest bridge o f technical importance was constructed over the Euphrates and connected the two parts of the ancient city of Babylon; it is supposed to have been built by Nebuchadrezzar. The river is 1000 yd wide at that point, and more than 100 stone piers were erected in it. On them, the platform of the bridge was placed; it was 30 ft wide, made of beams cut from palm-trees, and was roofed. There were several technical weaknesses; in the first place the space between the stone piers, whose width is unknown, was very small, perhaps
17 to 20 ft. Narrow gaps and a large number o f piers would be a great hindrance to the flow of the river, causing blockages and flooding at high water. The method o f building under water was not known, and the river had to be diverted during the construction of the bridge. The piers were pointed upstream, so that the water broke easily on them, and were blunt on the downstream side.

попаданец бы соорудил 10-15 быков не отводя воду и поставил бы ферменные деревянные пролеты

минойский — The bridge at the Palace of Minos in Crete
was 36 ft wide, and the culvert bridges o f the viaduct were 15 to 20 ft wide.

min 1,300 m more like 2000 m
Wooden logs … a total weight of 855 tonnes.

Herodotus tells of a boat-bridge across the Struma made by the Persian king Xerxes, and describes the construction o f a later one:

They stretched cables from the land, twisting them taut with wooden windlasses. For each bridge two cables of flax and four of papyrus were used. When the strait was bridged, they sawed balks of wood to a length equal to the breadth of the floating supports and laid them in order on taut cables, and having set them alongside they then made them fast. They then heaped brushwood on the bridge, and heaped
earth and stamped on it. They made a fence on either side lest the beasts of burden should be affrighted by the sight of the sea below them.’

> Three openings were provided for the passage of small boats.

The surface current to the Mediterranean flows at an average speed of 1 1/2 knots but varies according to wind directions

the narrowest part of the Dardanelles between Çanakkale and Kilitbahir (40°8′38.32″N 26°23′23.45″E) is about 1.4 km (1,530 yards) wide and has a maximum depth of 91 m (299 ft).[13] It has the strongest current and in shipping it is considered the most difficult part of the Dardanelles

Pontoon bridges across rivers are usually held in position by anchors fastened to the bow and stern of each boat[19] and thus, at a first glance, Herodotus’ description appears to be correct. However, the depth of the strait is not mentioned at all in his Histories.

The length of anchor ropes must be several times the depth of water in order to prevent damage to the ship caused by a jerking anchor rope and to prevent the anchor from dragging along the seabed. Ships in the center of the strait would thus have had to use anchor ropes with a length of several hundred meters each. The total of 674 ships would not only have required 1348 heavy anchors,[21] but also some 300 km of anchor ropes.

Even if iron anchors existed already then,[22][23] it is unlikely that the iron manufacturing was capable to produce some 183 tonnes of iron anchors.

If the beam of a penteconter is taken to be 4 m (13 ft),[22] the bridge consisting of 314 ships spread across 2,200 m would show gaps of some 3 m (9.8 ft), if the openings made by triremes are disregarded.

when he describes the bridges rebuilt after the storm he gives a single indication saying that the weight of the cables made of white flax was one talent per cubit what roughly translates into 26 kg/46 cm[29] or 56.5 kg per meter.[30] Using various methods of conversion one arrives at diameters between 23 and 28 cm (between 9 and 11 inches)![31] Cables weighing that much cannot be handled, it is almost impossible to bend cables with such a diameter or to reel them on a cable drum — which probably did not yet exist at that time — or to put them into any other transportable condition. Bollards of several meters in diameter would have been necessary in order to fasten these cables without breaking them.[32] Herodotus appears to talk about undivided cables reaching from shore to shore. However, a single cable of 2,200 m would have weighed 124.3 tonnes and even today could not be transported by any practical means

a total weight of some 13 tonnes which appears to be a reasonable load for the ships of that time.

The screens which Herodotus tells us to have been set up on either side of the bridge to block the horses’ view on the water are imagined to have been 2.74 m (9.0 ft) tall, constructed out of tree limbs and with smaller limbs and other plants woven through these poles in order to make a solid wall.[45] Only one such screen on the bridge of 2,200 m would thus have had an area of some 6,000 m2. Even during a very gentle breeze, the wind loads on this huge area could not have been controlled by the means available at that time.[46] Pontoon bridges of the last centuries have shown that it is entirely sufficient to have simple guardrails made of wooden lattices or ropes in order to keep the horses on the bridge.

Я бы предположил, что проблема в самом процессе роста.
Обычное дерево растёт в высоту тонкой веточкой, причём удлиняет его только самый кончик с верхушечной ппочкой. Затем дерево растёт в ширину. Причём растёт только в зоне камбия, между корой и древесиной. Чтобы расти в виде трубы, придётся куда-то девать древесину из центра.

У бамбука несколько зон роста, в каждом колене. Поэтому он использует эффективную трубу.

Горев, «Металлические конструкции», Т.1, п. 5.4.6 Соединения поясов со стенкой, стр. 250, формула (5.96).

Сдвигающее усилие T = Q*S/J, где Q — перерезывающая балку сила, S — статический момент сдвигаемой части сечения относительно нейтральной оси, J — момент инерции сечения балки в целом.

Впрочем, вывод формулы предполагает, что пояса и стенка из материала с одинаковым модулем упругости. Что из предположений изменится, если материалы разнородные, так сразу не скажу.

Ствол дерева сложно назвать примитивным одиночным стержнем — это весьма совершенный композитный элемент. Стебель бамбука, хоть это и не дерево, вообще труба с усиливающими диафрагмами.

Угу… Жил в Миннеаполисе, рядом со мной здоровенный мост в Миссисипи нагребнулся. А я по нему, сцуку, регулярно ездил…

Тут не в материаловедении дело, а в распространенности идиотов и специфичности системы…
Борьба двух максим: «любое ЧП имеет ФИО», и «наказываем невиновных, награждаем непричастных».

хех
// when a bridge in Pennsylvania broke under a train in 1850, all metal structures on the New York and Erie Railroad were ordered replaced with wooden bridges, according to Llewellyn Nathaniel Edwards in A Record of History and Evolution of Early American Bridges (Orono, Maine, 1959, p. 61).
// they came to be regarded as superior to wooden structures in the second half of the 19th century because of the increasing availability of iron at decreasing cost, the growing scarcity of timber and its increasing cost, and the resistance of iron to fire damage,

Я то думал что современные мосты почти абсолютно надежны. Но судя по Bridge Failure Rate by Wesley Cook шанс обычного регионального американского моста развалиться — 1/5000 в год, порядка 130 мостов в год.

Building with Iron A Napoleonic Controversy
Pont des Arts(1801) bridge … the fallacy in the design, as in that of the first British cast iron bridge in Coalbrookdale … was that it imitates forms of timber construction in which the members are submitted to both tension and compression

показано — забивание свай опускного колодца(открытый кессон), осушение водяным колесом, установка опор, сооружение арки на деревянных лесах, установка блоков краном

самое важное
// Интересно, что по легенде первый камень был заложен самим императором 9.7.1357 в 5:31 утра. Эта дата и время были выбраны по рекомендации астрологов. Если записать числа следующим способом: 1 3 5 7 (год) 9 (день) 7 (месяц) 5 (час) 3 1 (минуты), то получится сначала восходящий, а потом нисходящий ряд нечётных чисел (палиндром)

Impregnated значит чем то пропитано, вопрос в том, что это может быть как пропитка каменноугольным дегтеи (что для лиственницы даже излишне и с клееным брусом плохо сочетается), или фенольной смолой.

Хотя возможно и эта причина работает

// That has the disadvantage, unlike for the suspension bridge, that the cables pull to the sides as opposed to directly up, which requires the bridge deck to be stronger to resist the resulting horizontal compression loads, but it has the advantage of not requiring firm anchorages to resist the horizontal pull of the main cables of the suspension bridge.
https://en.wikipedia.org/wiki/Cable-stayed_bridge