In Hexi County, Hanzhou, three young people sit in a makeshift room on the edge of the Yellow River and are deliberating.

The young man at the head was dressed in a light scarlet official robe, quite handsome, and was a five-grade official. His next two young men in dark green official robes were quite handsome, at least much more handsome than Tang Laosi, who was eating ashes on the official road.

A combination of five products and two six products is a great existence in Hanzhou, Xiazhou, you must know that the history of Hanzhou is only from the fourth grade.

What are they doing on the banks of the Yellow River? Could it be an investigation of hydrology?

However, for such a matter as investigating hydrology, where will officials above the sixth grade be sent out?

I saw the scarlet-robed official at the head of the group and said to the green-robed official on the lower left: "Brother Du, it's been more than half a month, do you have any eyebrows on the site?" ”

It doesn't look like it's really looking at hydrology.

The green robe surnamed Nadu nodded and replied: "Wang Dong, according to the instructions and requirements in the young craftsman's letter, three places have been selected, one is Longmen Ferry, the second is Yukou two miles away from Longmen Ferry, and the third place is Dalongmen twenty miles away from Longmen.

Let's talk about Longmen Ferry first, where the river is only 80 meters wide, and the span of the bridge is the shortest. However, the mountains on both sides are cut like knives and axes, which is too dangerous, and if the bridge piers are set up here, the construction is more difficult, the risk is greater, and the ability to resist geological disasters cannot be estimated.

The second is Yukou, where is the exit of Longmen, the span is about 150 meters, the speed of the water here has slowed down a lot, but there is still no way to place the bridge piers in the river, which leads to the only way to set up a tower on the bank, and the distance between the towers is about 140 meters.

The last place is the Longmen Bridge, which will be built between Daqian Village and Cangtou Village. The water flow is stable, and the piers can be placed by boat, or a gap can be intercepted to build the piers. However, the disadvantage here is that the span of the bridge is too long, at least eight miles away, and the investment is too big! ”

In the entire Tang Dynasty, there is only one handsome young guy who can be called Wang Dong, and he is Wang Xuance. Supplemented by the content of the conversation, you can guess with your toes that these three people are the Datang Road Supervision Trio, Luoyang Wang Handsome, cousin Changsun Chong and Du Wei.

After nearly a year of official road construction, Du Wei and Changsun Chong have long since changed from civilian to technical streams.

Otherwise, how could Du Gou put forward a detailed proposal for three bridges and ferries?

In fact, Wang Xuance and the three pushed the construction of the official road to the edge of the Yellow River as early as two months ago. If it weren't for the natural danger, at this moment, I am afraid that the plan issued by Tang Laosi to connect Taiyuan first is not far from the end.

As early as two months ago, Wang Xuance reported the matter of natural danger to Tang Heshang in the form of flying pigeon handwriting, and Tang Heshang copied the design drawings while choosing a plan from his mind when he was in Hanyang.

Later, because of the death of Li Gang, it was delayed for more than a month, and it was sent to Wang Xuance and the others.

After Wang Xuance and the three of them demonstrated the plan, it took half a month to select the site. That's why we have today's meeting of the Big Three.

After listening to Du Wei's report, Wang Xuance turned his gaze to Changsun Chong: "Eldest grandson, you are in charge of safety and technology, tell me your opinion." ”

"No!"

Changsun Chong was not ambiguous, nodded and said: "Judging from the surveying and mapping results given by Brother Du, it is indeed these three places that are most suitable for bridge construction. ”

However, I would like to reject the idea of building a bridge directly at the Dragon's Gate. After all, after years of erosion by the turbulent river, no one knows whether the geology beneath it can withstand the weight of the bridge piers. Besides, as Brother Du said, the danger factor of building bridges there is too great, and it is not easy for our craftsmen to train, so they can't be allowed to take risks.

Secondly, speaking of Yukou, although the water flow there is not so turbulent, it is much more turbulent than Daqian Village! Therefore, I personally think that building the bridge in Longmen is the best choice, although there is a larger span and more investment. In terms of safety, it is the most suitable place! I asked a villager, Daqian Village, the depth of the Yellow River is not deep, we can build bridge piers by intercepting the river. ”

After listening to Changsun Chong's idea, Wang Xuance fell into deep thought.

After a long time, Wang Xuance spoke: "Eldest grandson, Brother Du, I thought about it for a while, and I think it is not very suitable to build in Daqian Village!" The span is too big, the bridge is too long. Eight miles away, how much cement and how much steel do we have to use? I'm afraid that all the steel produced by your family in three years will not be enough!

Secondly, I don't agree with the way the barrage is built, because with our current construction technology and equipment, it is not realistic to intercept such a wide river.

In the end, it takes too long. You know about the Wang family and Shiro, I don't think Shiro is willing to wait so long.

Therefore, I tend to build the bridge at Yukou, although the current is fast, we can only build the piers by the river. The distance between the towers is only 140 meters, and as long as we don't build the bridge too big, it should be able to bear the weight. ”

"I agree!"

Du Wei nodded, he agreed to build the bridge in Yukou in his heart, where the cost is the lowest and the timeliness is relatively fast.

If the three of them encounter any disagreeing opinions on weekdays, most of them are resolved by voting. Now Wang Xuance and Du Gou both think that it is appropriate to build a bridge in Yukou, and Changsun Chong naturally no longer insists.

"Then do it!"

Wang Xuance nodded and said: "The design plan for repairing the bridge given by Shilang, you two go back and study it carefully, this will be our first cement reinforced bridge in Datang, and you can't be sloppy!" At the same time, you also selected a set of compromises according to several sets of design plans given by Shiro, and we started construction immediately after we decided. ”

"No!"

"No!"

Tang Laosi gave the bridge repair design drawings of Changsun Chong and Du Wei naturally knew, not only knowing, but also very familiar with the more than ten consecutive days of reading.

Three sets of cable-stayed bridge designs, one set of double-flex arch bridge design.

To be honest, if the four designs were placed in the era when the system came, it might be really fine. In particular, the design of the last set of double-arch bridges.

The two arches are built on the east and west banks of the Yellow River, and the other end of the arches is placed on an island in the river.

However, in the Tang Dynasty, the island in the river has just begun to form, how big can it be?

Du Wei and Changsun Chong discussed for three days, and finally decided on the next plan - suspension cable-stayed bridge.

After another ten days of revision, the design drawings designed by Tang Laosi and modified by Changsun Chong and Du Gou were finally released.

With a single-span and single-chain suspension structure, the tower spacing is 100 steps, the carriageway is two zhang wide, the sidewalks on both sides are three feet wide, and the steel tower and concrete mixing frame are six zhang high......

It seems that this design scheme is not much different from the Yukou suspension bridge in a certain era.