For a large river like the Yangtze River, it is extremely difficult to build a bridge on it.
Not to mention the contemporary Tang Empire, even for future generations in the 21st century, the construction of a bridge on such a large river would be extremely difficult and would require huge investments.
This is why the Tang Empire has long considered building a bridge across the Yangtze River, but it has never been possible because the technology was too difficult and the cost was too high.
Around the 30th year of Xuanping, the empire considered building a Yangtze River bridge in Jinling and Hanyang. The main purpose was to connect the railways on both sides of the Taiwan Strait.
But it never happened due to technical issues.
Because even the Yangtze River Bridge at the planned site in Hanyang will be more than 1,600 meters long. If the approach bridges are included, the total length will be even greater.
As for the Jinling side, the Yangtze River is wider, with a preliminary design length of more than 4,000 meters, and the water is deeper and construction is more difficult.
At the same time, the navigation situation of the Yangtze River must be taken into consideration. Just like the Huangpu River, when building a bridge, the navigation situation must first be considered. And as time goes by, the demand for navigation will become higher.
In the early years, when the Tang Empire planned to build a bridge on the Huangpu River, it initially said that it would be enough to meet the navigation requirements of ships with 5,000 tons. But later, the standard became higher and higher, and 5,000 tons became 10,000 tons, and then
to fifteen thousand tons.
Later, when the Ministry of Industry of Datang and Songjiang Prefecture listened to experts from the Department of Architecture of the Royal Institute of Technology saying that a steel suspension bridge could be built, they simply did not bother with the 81,000 tons.
, directly reaching a water surface height of 35 meters. This height can definitely meet the navigation needs of most types of ships now and in the future.
When building bridges on the Huangpu River, navigation needs to be considered, and when building bridges on the Yangtze River, this is even more important.
Because Yangtze River shipping is currently the main artery of the empire's inland river shipping, it is responsible for most of the transportation tasks of the Tang Empire's inland river shipping, especially the middle and lower reaches of the Yangtze River, where ships are constantly coming and going, and there are many ships sailing on the Yangtze River.
The tonnage is also very large.
Generally speaking, although most of the ships currently sailing in the middle and lower reaches of the Yangtze River are inland river ships of only a few hundred tons or one to two thousand tons, there are also ships of several thousand tons or even tens of thousands of tons.
In the summer, there are often 10,000-ton cargo ships going up the river and heading straight to Dangtu Industrial Zone.
At the same time, we must also consider that the Tang Empire continues to dredge the Yangtze River, and the navigation conditions of its main channel are getting better and better. It will be normal for 10,000-ton cargo ships to enter the Yangtze River in the future.
Therefore, when building the Yangtze River Bridge, especially in the middle and lower reaches of the Yangtze River, the navigation of 10,000-ton ships must be met.
And it is actually not easy to satisfy this point.
In fact, if it were not for the purpose of meeting the needs of ship navigation, but simply to build a bridge connecting the two sides of the Yangtze River, the Tang Empire could have done this long ago.
Isn't it just a bridge several kilometers long? If it doesn't work, the engineering troops can be deployed directly and a pontoon bridge can be erected.
But this cannot be done in reality. If a bridge is built to block the waterway, shipping on the Yangtze River will be completely abolished.
Due to many circumstances, the construction of the Yangtze River Bridge and even the bridges on other rivers in the Tang Empire came to a standstill. For a long time, ferries were relied upon to communicate cross-strait traffic.
For example, the railway ferry in Jinling is famous for its use of large ferries to directly transport trains across the river. At its peak, it could transport dozens of trains a day.
However, as the industry and commerce of the Datang Empire continued to develop, the railway transportation became increasingly busy. In order to solve the railway transportation problem, the Datang Railway Corporation had long begun to double-track the single-track railways built in the past, and the speed of the trains
Continue to speed up.
Now basically the speed of passenger trains can reach 60 kilometers per hour.
However, the existence of rivers such as the Yangtze River has restricted the further development of railway transportation volume.
Datang Railway Corporation has long wanted to build a Yangtze River bridge that can carry trains. Well, not only the Yangtze River Bridge, but also many cross-river bridges such as the Huaihe River, the Yellow River, and the Pearl River.
After the Huangpu River Bridge was successfully completed and opened to traffic, Datang Railway Corporation couldn't wait to apply, saying that the technology was mature, and applied to build high-end bridges on several rivers such as the Yangtze River and the Yellow River.
The first among them are naturally the Jinling Yangtze River Bridge and Hanyang Yangtze River Bridge.
Because these two places need to connect the railways on both sides of the Taiwan Strait to achieve a seamless connection between the railways on both sides of the Taiwan Strait.
After Li Xuan received the report, he did not directly approve or reject it. Instead, he forwarded the report to various cabinet ministries, especially the Ministry of Industry.
Soon after, the Ministry of Industry convened a meeting with Datang Railway Corporation, the Department of Architecture of the Royal Institute of Technology and other relevant institutions to discuss the feasibility of building a bridge on the Yangtze River.
During the meeting, several leading professors from the Department of Architecture at the Royal Institute of Technology gave officials from the Datang Railway Corporation and the Ministry of Industry a very positive answer, that is, with the current technical conditions, it is possible to build a cross-river bridge on the Yangtze River.
, and it can ensure that the bridge can still navigate ships of 10,000 tons.
Today, the bridge construction level and experience of the Tang Empire have been fully tempered in the past few decades.
In the past few decades, when the Tang Empire was building infrastructure in various places, it was indispensable to build bridges, and even built several bridges across the Yellow River.
Among them, the Zhengzhou Yellow River Bridge, an important railway bridge connecting the Northern Railway, is a typical example.
Moreover, the Zhengzhou Yellow River Bridge was actually built very early. Construction started in the 25th year of Xuanping. It was completed and opened to traffic in the 28th year of Xuanping. The total length is more than 3,000 meters.
However, when this bridge was designed, it basically did not consider the navigation of ultra-large tonnage ships, and gave priority to the passage of trains. There is also an attached bridge for pedestrians and horse-drawn carriages to pass, so it was built using a dense bridge hole method, with hundreds of bridge holes.
Well, the technology used is also very general.
Of course, even so, this is the longest modern bridge ever built by the Tang Empire so far.
However, if we want to compare the technical difficulty, it is far inferior to the just-completed Huangpu River Bridge.
Not only on the Yellow River, but also on other river sections where navigation of large-tonnage ships does not need to be considered and where the geological conditions are good, the Tang Empire has built many bridges.
A lot of lengths ranging from hundreds of meters to thousands of meters!
But in the middle and lower reaches of the Yangtze River, there is currently no bridge. Now professors from the Department of Architecture at the Royal Institute of Technology say that the technology has matured, so the Tang Empire will naturally not delay.
After confirming the reports of his subordinates, Li Xuan quickly approved the construction applications for the Hanyang Yangtze River Bridge and Jinling Yangtze River Bridge.