Chapter 794: Cement roads are easy to repair, but building bridges is difficult

The difficulty of building cement roads is much lower than the difficulty of opening roads in dense forests. After all, it doesn't need to cut down trees. In fact, the amount of labor involved in cutting trees is not great. The really large amount of labor is digging the roots and transporting the trunks and roots away.

In the tropical rain forest, there are so many thousand-year-old trees, each with a height of dozens of meters, and the area of ​​the tree roots is extremely large. The older the tree, the thicker the roots, and the intertwined roots, the distribution area is quite large. The roots of the roots of these thousand-year-old trees are widely spread, and they are all digged into the depths of the soil, making it extremely laborious to dig up.

Therefore, it took the colonial team of Panama led by Gorad to open up this path for so long. In addition to cutting down trees, it is also necessary to consider the drainage problem and choose a higher terrain. Also, try to avoid rivers. After all, if you cross another river, you need to build a bridge.

In this era, without construction machinery, bridging is very troublesome. For example, a small stone bridge requires a lot of stonemason to spend several months to build. As mentioned in this report by Gao Laud-this road has to pass 24 small rivers and 3 large rivers ... The 27 bridges are as troublesome as the entire cement road ...

Building a concrete road is actually very simple. Without a roller, Marin can allow the stonemason to build more stone pits, and let a few black people pull the roadbed together with fiber ropes. There are now more than 6,000 strong black slaves under Gorad. As long as there are enough stone pits, it is relatively simple to lay the roadbed.

After laying the roadbed, it is to pay off with lime. This needs to be measured to ensure that the distance between the two lime lines is 3.5 meters or 4 meters. This is not difficult, just take a ruler and measure it.

After that, bricks were erected on both sides of the road ...

The purpose of the vertical brick is to set a limit for the cement poured on the cement pavement. At the same time, the height of the brick standing is the thickness of the concrete pavement. Therefore, the purpose of standing bricks, besides being a boundary, also means to refer to pouring cement. At the same time, there are bricks to protect both sides, and the cement will not leak to the outside. Of course, after the bricks are erected, you need to stir some of the cement between the bricks to fix it.

After that, the biggest problem was cement mixing. Cement mixing is a pure physical activity, and it also requires technology. Because, in addition to the good mix of cement and sand, it is necessary to pay attention to the amount of water mixed. It is not enough to add more or less, which will affect the quality of cement. Therefore, this session requires professional participation. At least, a professional must show how to mix labor.

After mixing the cement, the rest is simple. Let the young adults fill the mixed cement in a bucket and pour it between the bricks standing on both sides. Then, just pat it on the board and flatten it. When I saw the pressure was almost the same, I would use a long wooden board or a long stick to stick to the upper edge of the bricks on both sides and scrape it hard. By using a large wooden board to press down on the pavement, the pavement is tight enough.

The last step is to cut the square and tie the line. The cut is that every other section of the cement road will be cut with a knife, so that the road is divided into pieces. In fact, this is to prevent road cracks from appearing on the exposed cement surface due to thermal expansion and contraction. The threading is to use a knife-shaped wooden board to press a shallow line on the exposed surface of the cement. These shallow lines are to prevent the concrete pavement from being too slippery on rainy days ...

It is not difficult to irrigate and post-process the cement pavement. On average, hundreds of people can lay one kilometer a day. There are more than 6,000 strong black slaves in Gorard. Even if black people are not proficient in labor, they can do it for a few kilometers a day. The premise is that Marin needs to send a group of craftsmen to guide them.

Finally, there is the problem of drying the cement pavement. This stage takes a long time, and it usually takes one month (standard 28 days) before the cement road can be put into use. Until then, the cement surface needs to be maintained. I'm not afraid of drying in the air, and I'm most afraid of raining halfway.

Therefore, during the drying period of the cement surface, it is necessary to prepare shelters. For example, straw mat, straw curtain or something. Once it rains, cover the exposed surface of the cement that has not been dried to avoid continued moisture and extend the drying time.

It is precisely because the drying period is too long, so the construction time of a general cement road, even a small rural cement road of several kilometers, takes several months. It's not that it takes so long to build a cement road, but it takes one month to dry a one-kilometer cement road ...

Therefore, as long as the materials are complete and instructed by skilled craftsmen, the cement road can be repaired very quickly. But Marin did not expect how fast they would repair. Why? Because the time to lay the roadbed is uncertain ... Hyundai has a roller to help, and it takes a short time to lay the roadbed. And with Uncle Black pulling Shi Yong to make way, God knows how long it will take ...

...

In fact, it is not difficult to build a village-grade cement road as long as it is a way out, even in this ancient time. However, the 24 small bridges and 3 bridges made Marin's brain hurt.

This era is not a later generation, with a large number of construction machinery. Marin remembers that the bridges built in later generations can reach one building in 5 minutes at the fastest. Of course, that kind of bridge. As long as the crane hangs a cement slab (or simply iron slab) made of reinforced concrete on both sides of the creek, a proposed bridge will succeed.

However, there are two premises, that is, the strength of cement board or iron board is high enough. Because, this is going to be ridiculous, the carrying capacity must be strong. In addition, this bridge is only suitable for small creeks. The slightly larger river is not so easy. As long as it involves building bridge piers, it is not simple. If it is built into an arch bridge like Zhaozhou Bridge without piers, the project is more difficult.

However, Marin now does not have high-strength cement slabs, nor would he be willing to make such large iron slabs to be used as small bridges. Now that iron is so expensive, then the big iron plate may be stolen ... And, before the stainless steel comes out, ordinary steel bridges, wind and rain, it is easy to rust, and then collapse ... Besides, even if there is stainless steel, Nor can it be extravagant to build a small bridge. At least, in this era, no fool would use a baby like stainless steel to build a small bridge ...

If you use traditional methods to build a bridge and build a small stone bridge, you need a large group of stoneworkers to work for a few months to complete. The 24 stone bridges require a lot of craftsmen and long working hours. It is estimated that the 24 small stone bridges have been completed, and the estimated time spent is more than two or three years.

This is still a small bridge, the bridge is even more finished. In this era, there is no ability to build bridges. Without the cable stay technology, the bridge pier must be used to build the bridge. However, building bridge piers is a technical job. The pier of the small bridge is easy to handle, and the pier of the bridge is difficult to get. Because you have to drain the bridge pier first. Then you can piling. Before piling, calculations and site selection are required ... A whole set is down, which is very troublesome ... With the current technology, whether it is to drain part of the big river or to construct large bridge piers, it is difficult to do .

Of course, it is a pity to learn the Luding Bridge on the Dadu River, where the iron rope crosses the river, and then it is covered with wooden boards ... However, such a bridge is the most crowded and cannot be moved by carriage. But the cement road that Malin built in the Panama isthmus was used to transport goods. In the future, the carriage must be heavy to transport the gold and silver produced by the Potosi Silver Mine. This kind of cable-stayed bridge must not be used to ride a carriage full of gold and silver ...

If you fill the river and build bridges ... the bridges on the small river are OK, and the three big rivers want to fill the river and build bridges is definitely not realistic ...

"Is it possible to use the ferry method to cross the river?" Marin scratched his head in the captain's room.

However, letting a carriage full of gold and silver on the ferry boat is very troublesome, and it is easy to delay time. If a robber took the opportunity to intercept halfway, it would be very bad.

Troubled, Marin took a rest on the deck and looked out over the sea ...

Walking on the deck ...

"Deck!" Marin shuddered ...

"It seems that the pontoon can be built!"

The army marches often build pontoons. Generally, the pontoon is built by ships, rafts, etc., and can temporarily march.

However, there is a trouble with the pontoon, that is, it affects the navigation of the river. If the temporary pontoon is fine, if a long-term pontoon is built, then this pontoon is equivalent to cutting off the navigation channel of the river. If the pontoon is not withdrawn, do n’t think about other ships ... Then, the inland navigation of this river is abandoned ...

So, generally speaking, no one wants to build a long pontoon on the river. Only when marching, the pontoon was temporarily built.

Marin did not bring a civil servant, nor did Schwartz. He didn't know who to discuss with. So, he had to play the piano like a cow and raised a mouthful with Kahn, the rammed cargo.

As a result, Kahn, who was fighting a roast duck, asked strangely:

"Master, what is inland shipping? Why are you doing inland shipping in Panama?"

Seeing the look of Kahn's curious baby, Marin almost vomited blood in depression. But suddenly, he reacted—

"Yeah, why should I consider core shipping in Panama?"

The Panama area is originally a colony, and Marin doesn't want to do big development there. Why should he bother about the problem of the inland waterway being affected there? To put it bluntly, there is no inland shipping there. There may be, but it is just a native Indian canoe. Even if you encounter a pontoon blocking a river, carrying a canoe and going around is ...

I was also stunned, and considered the Panama region as a cost soil. In fact, the only thing useful to Marin in the Panama region is the relay function here. Others, Marin can ignore it ...

After suddenly realizing it, Marin found that these 24 small bridges and 3 bridges seemed to be replaced by pontoons ...

Marin first planned to send shipbuilding craftsmen to Panama, using the locally harvested wood to make more inland vessels, and then rowed across the river to make a pontoon.

However, it takes a long time to build a ship, and it is also very waste material ... Marin needs to realize the opening of the Panama Isthmus cement road as soon as possible, so he does not want to wait slowly ...

After thinking about it, Marin suddenly found out that those logs felled by the tropical rainforest seemed to be directly tied into a super-large raft, lying across the river ...

The logs are floating, and the larger the log, the stronger the floating capacity. A pile of tens of meters of felled logs is gathered and tied, and it is easy to form a pontoon across the river. Moreover, the load bearing capacity is very strong. At least, passing a carriage is not a problem.

Even a big river (in fact, the big river in Panama area is not very big), as long as enough logs are obtained, tied or nailed into a group, it can cross the big river.

So many dozens of meters long and thick logs are lined up to make a pontoon, and the carriage is not a problem ...

Moreover, Gorad took thousands of black people to cut down an 80-kilometer-long road from the tropical rain forest by cutting trees, halfway down with huge logs that were cut down. As long as a lot of manpower is used to push these logs along the road down the river, and tie them into a super-large raft, traverse the river, you can make a large pontoon that can be used as a carriage.

Because the log source is extremely rich, it takes little time to get such a pontoon. Even if there are 27 bridges, it is not very troublesome ...

Of course, the pontoon made of this oversized raft will not have a long life. But what Marin needs is to put it into application quickly, and quick success is the most important. As for the long-term point, Marin will build a concrete bridge beside the pontoon to replace this pontoon made of logs. However, because of the staring of the floating bridge made of log rafts, the construction of cement bridges or stone bridges is less stressful. It is enough to use the log raft floating bridge first ... then have the energy and financial resources to build a regular bridge , To replace this temporary pontoon ...

However, the pontoon bridges on those 24 small rivers are easier to be replaced by cement or stone bridges, but the bridges on those 3 large rivers are difficult to replace. After all, the river is too wide and the amount of water is large. With the current technology, it is difficult to build a bridge across the river.

However, fortunately, the log resources in Panama are very rich ~ www.wuxiaspot.com ~ can be cut everywhere. It ’s a big deal. If it breaks, cut a few more trees to repair the three log pontoons ...

Thinking of this, Marin immediately wrote an order document and sent someone to Panama:

"You can use giant logs that have been felled, tied or nailed into giant rafts, across the banks of the river, to make bridges to ensure the unimpeded carriage ..."

Anyway, the meaning of Marin is very clear-a pontoon made of giant rafts will connect this road first. As long as this road is open, whether it is to transport the valuable goods transported from Daming on the Pacific route, or to transport the silver of Peru and the saltpeter of Chile, it can be started. With the profit accounted for, it would be simpler to withdraw funds to repair the bridge in due course. Anyway, with the pontoon, regular bridges do n’t need to be repaired in a hurry ...

Even a broken pontoon can last for several years. There is no sea maggot erosion in the Tamsui River, and the pontoon has been maintained for several years or more. Before the end of the life of the pontoon, the 24 small bridges along the line will be replaced by regular bridges. It is estimated that it can be done. As for the bridges over those three big rivers, I can only say more. With the level of engineering technology of this era, God knows when a regular bridge across the river can be built ...

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