The architecture of the Tang Empire is actually quite interesting, the entire Chang'an City is a big square, there are more than a hundred small squares in it, and each small square is a square.

And each square has four square gates in the east, west, north and south, each square gate is in the center of the position, the east gate and the west gate are a street that communicates, and the same is true for the south gate and the north gate, so that the interior of each square will form a cross street, and the area in the square will be divided into four small squares.

Similarly, if the four squares are divided equally by the Crossstreet, the area of the quarter square will be divided into one-sixteenth square with the smaller Crossstreet.

The width of the cross street in the square is narrower than the outside road, and the width of the small cross street is even smaller, the width of the general cross street is fifteen meters, which is equivalent to the width of the two-way four-lane road surface in later generations, which can be said to be very wide, and the width of the small cross street is only five or six meters, which is relatively too narrow, after all, the cross street is the main traffic artery in the square, and the traffic pressure of the small cross street is much smaller.

However, even if the large and small cross streets are divided into one-sixteenth square, it is still a large area, such as the most famous Pingkang square, the area of one-sixteenth square, is also a behemoth with a length of more than 200 meters and a width of more than 100 meters.

Many aristocratic mansions occupy such a large area, for example, Gao Xianzhi's house, Yang Yurou's house, etc., and Yang Guozhong is even more excessive, his house occupies two one-sixteenth squares, accounting for one-eighth of the area of Xuanyang Fang.

And Mrs. Han and Mrs. Qin Guo are too low-key, both of their houses are only one-sixty-fourth, from one-eighth, one-sixteenth, to one-sixty-fourth, you can see that their status is different.

No matter what era it is in, a house like this covering an area of five or six thousand square meters, two or three thousand square meters, or even seven or eight hundred square meters can be regarded as a mansion.

In other words, the mansion of Mrs. Qin Guo, which occupies one-quarter of the area of Xuanyangfang, is also ten times the size of ordinary people's houses, which is not small.

One sixteenth square of each square is a basic unit, in this area with a length of more than 200 meters and a width of more than 100 meters, there are forty or fifty houses neatly distributed, and for the convenience of walking, in this small area, there are also smaller lanes, there are two lanes in the east and west and north and south, and the distance between these four lanes is narrower, only two or three meters wide, only able to accommodate one car to pass.

The bustling area of Pingkangfang is precisely around this kind of small alley, where the roads are very narrow, and the small cross street with a width of five or six meters, and the cross street with a width of fifteen meters, are all on the edge.

Due to the limited space in the courtyard of the brothels and restaurants in the green house, this directly leads to a lot of guests who come to consume, there is no way to park the vehicle, whether it is a new car, or an old-fashioned carriage has no way to park, helplessly, can only park on the edge of the cross street, and even, park on the small cross street that is not too wide, thus further causing a very serious congestion.

But if you don't come by car, how can you reflect the identity and status of nobles and wealthy people, wouldn't it be too embarrassing.

Even in later generations, many young people are not happy without cars, as long as they are men without cars, they basically don't even want to find a girlfriend, which shows how strong people's vanity is.

The alley is only two or three meters wide, and it is not practical to build an underground parking garage underneath, and it is impossible to park vehicles normally, while the small cross street with a slightly wider width has a width of five or six meters, and it is feasible to build an underground parking garage, and a cross street with a width of up to 15 meters can build a larger underground parking garage.

According to Ang Lee's prediction, a long small cross street can only accommodate forty or fifty parking spaces, and the shorter one can only accommodate more than twenty parking spaces.

The wider cross street, can accommodate more parking spaces, the width of 15 meters, can park three rows of vehicles, can also leave two rows of space in the middle, the width of the car is two meters, then, the east and west streets of Pingkangfang, each can park more than 750 parking spaces, South Street and North Street are only more than 100 meters long, parking vehicles are less, each can park more than 300 parking spaces, if the entire cross street is completed, can park more than 2,000 vehicles.

The narrower small cross streets, all of which were built, could only park 150 cars, a gap of more than ten times.

Because of the construction of underground parking garages, there is no precedent in the Tang Empire, so it is impossible to complete the construction of all the large and small cross streets in Pingkangfang, and can only selectively build two to try, if the effect is really high, it is not too late to carry out large-scale popularization.

Looking at the architectural drawings of Pingkangfang, Li An immediately chose the location, that is, the North Street and East Street of Pingkangfang Cross Street, the area enclosed by these two streets is the most prosperous area in the whole Pingkangfang, there are a large number of brothels and restaurants in Qinglou, and the daily flow of people is also very large, and the requirements for parking are relatively high.

However, with the wall being torn down and the street outside wider, it would not be a problem to build an underground parking lot under the avenue outside, and it is estimated that more than 1,000 cars would not be parked in a short section of 500 meters.

But the problem is that there is no precedent for Datang, and if such a big project is done in the cross street of Pingkangfang, the impact will already be great, and if the avenue outside is also built, the resistance will inevitably be greater.

Even if the North Street and East Street of Pingkangfang collapse, it will only affect Pingkangfang, and if the avenue outside collapses, it will affect a large area of the capital, even if the imperial court supports the construction of underground parking lots, it has to consider this aspect of the problem, no one can be 100% sure that the construction of underground parking garages will be successful.

Now that the location has been selected, then, the next work is the design drawings, the construction of the underground parking garage, for the current technology of Datang, there is no difficulty, however, the design is a very important part, if the design is not clever enough, it is relatively troublesome to use.

Ventilation and ventilation are the most basic requirements, lighting must also be considered a little, and it is necessary to be convenient, there must be multiple entrances and exits, and the import and export can not be too much, otherwise, it occupies too much space, and the amount of the underground parking garage is less.

Whether it is ventilation or ventilation, it will occupy the space on the ground, that is, while building an underground parking garage, the space on the ground also needs to be used to a certain extent, so that the road on the ground becomes narrower than before.

The passage of 15 meters is too wide, in fact, the width of 10 meters is enough, leaving a distance of 2 meters and a half on each side, which can be used to build lighting and ventilation facilities.

But because the ventilation and lighting facilities are separated from each other before there is one, in this way, the vacant distance in the middle can be temporarily parked, and these facilities are not very large, and will certainly not occupy a width of two meters and five, so that the sidewalk can also be formed on the outside, so that pedestrians can pass freely, so as to ensure the safety of pedestrians.

Ventilation, lighting, import and export, Li Ang drew drawings little by little, almost all the details were drawn on the drawings, and any small detail must be paid attention to, which is related to the success or failure of the construction.

It took Li An a long time to finally draw out the construction drawings of Pingkangfang North Street and East Street, and also marked a large number of technical details and the demand for materials, etc., and strive to do a good job in this project, so as to help King Guangping smoothly obtain status, and then support the current prince from the side.

Although in Ang Lee's eyes, the current prince is a turtle with a shrunken head, but the other princes are not very good, none of them are what Ang Lee can look at, so, it is better to support the current prince, besides, Li An feels that Li Yu is indeed very good, as long as there is no turmoil in the Tang Dynasty, the current prince may not be able to survive Li Longji, in this way, Li Yu can directly succeed to the throne as the crown prince.

Such examples are not uncommon, the crown prince of the Ming Dynasty, Zhu Biao, died too early, earlier than Zhu Yuanzhang, so Zhu Biao's son inherited the throne naturally.

Li An, who was tired for most of the day, put down the pen and paper, went for a walk in the yard, twisted his neck at will, and tried to make himself comfortable.

On the other hand, after Li Yu thought deeply, although he already had some eyebrows, he still didn't know what to do about many details, and he didn't know what to do, and for these problems, only Li An could help him, so he had to seek Li An's help immediately.

Li Yu took the drawings he had designed, and hurried to Li An's courtyard outside the city, ready to ask Li An for advice to see if Li An had any better suggestions, but he didn't know that Li An had already designed a more complete underground parking garage.

"Ah Lang, King Guangping has arrived."

After completing the task assigned by Ang Lee, the housekeeper had already returned.

"I'm back so soon, and I've done everything I've done with you?"

Ang Lee asked.

"Ah Lang, don't worry, I have arranged everything, more than 100 craftsmen have been recruited, and we will be able to start work tomorrow."

The butler replied.

Li An nodded, very satisfied with the housekeeper's efficiency, paused, and said, "King Guangping is here, and he hasn't opened the middle door to greet him." ”

Although the emperor imposed great restrictions on the princes and grandchildren to prevent them from colluding with foreign ministers and posing a threat to the emperor's status, the focus is on the princes, and the defense of the emperors and grandchildren is relatively slight, after all, in the Tang Dynasty, as well as many previous dynasties, I have not heard of a few emperors and grandsons who directly succeed to the throne, generally sons inherit the throne, and occasionally younger brothers will succeed to the throne.

And the contact between the emperor and the prince is relatively small, which is even more reassuring, for example, Li Yu, the king of Guangping, and his prince's father, can't see each other a few times a year, if there is any conspiracy between their father and son, I'm afraid that no one will believe it, they don't meet each other and don't contact each other, and how to conspire, it is in this situation that Li Yu can be more bold and walk in with Li An, without worrying about someone reporting it, in addition, Li An is not a foreign minister with heavy troops, he only has one or two hundred escorts in his hands, and there are no more troops.

Soon, Li Yu appeared in front of Li An in a hurry, and Li An was still lazy and looked very tired.

"What's the matter, Li Shilang didn't sleep well last night?"

Seeing that Li An was so sleepy, Li Yu asked.

"Haha! I slept well, but I woke up too early, oops! Both eyes hurt! ”

Ang Lee said and rubbed his eyes.

Seeing Li An like this, Li Yu didn't know what to say, he just wanted to hand over the drawings he designed to Li An to take a look, but he learned that Li An's eyes hurt badly, so how could he be embarrassed to say it.

"Then Li Shilang must rest more!"

Li Yu held back a sentence for a long time.

"It's okay, it's okay, King Guangping is coming in such a hurry, there must be something!"

Ang Lee asked.

"It's just a little thing, the underground parking garage that Li Shilang said yesterday, after the king went back, he thought about it carefully, and it is indeed the only way to solve the parking difficulty, this is the design drawing, and please Li Shilang to look at it."

After speaking, he painted the drawings he had drawn all night and put them in front of Ang Lee's eyes.

Li An carefully looked at the design drawing drawn by Li Yu, and a smile appeared at the corner of his mouth, the level of this design is really not flattering, it is simply the level of primary school students, the ventilation is a few bamboo poles, and the design of light transmission is completely absent, if this is designed, it is estimated that no one will dare to go down.

"King Guangping has worked hard, in order to solve the congestion problem in Chang'an City, it is really troublesome, but this drawing is not good enough, there is still a lot of room for improvement."

Ang Lee said very tactfully.

"Isn't it a good drawing? Where does it need to be improved? ”

Li Yu asked humbly.

It's not easy for Li An to complain in his heart, where is this problem that needs to be improved, this is everywhere that needs to be improved! It's nothing, it's just a useless graffiti.

"King Guangping, please see, this is the drawing of the underground parking garage of Pingkangfang North Street and East Street that I just draw, the above one is the design drawing of North Street, and the one below is East Street."

Li An had no choice but to hand over the drawings he drew to Li Yu, so that Li Yu could study hard and see how well he drew and how well he drew them.

Li Yu took the drawing from Li An's hand, frowned and looked at it carefully, although he had not learned drawing, but because Li An drew a three-dimensional drawing, he could still understand it completely.

And after looking at the design drawings drawn by Li An, Li Yu was completely convinced, he suddenly had an urge to tear up the drawings he drew and swallow them into his stomach, the drawings he drew were really embarrassing, compared with the drawings drawn by Li An, it was nothing, just a baby's graffiti.