265: Chapter 265 Yellow River Bridge

The First Emperor and Li Si stopped asking questions; doing so would make them seem far too ignorant.

The two of them were, after all, the most outstanding men of this era, possessing vast knowledge and powerful memories, yet they seemed like complete novices in front of Zhao Fusu.

They found it impossible to communicate properly with Zhao Fusu.

The feeling was incredibly uncomfortable.

Zhao Fusu also stopped explaining; saying too much and having to clarify everything was simply too exhausting.

After the First Emperor and Li Si left, Zhao Fusu began the work of organizing the Mengniu Company.

Purchasing milk wasn't difficult; the primary challenges were sterilization and packaging.

What he needed was a way to store milk for a long period.

Therefore, he required Ultra-High Temperature (UHT) instantaneous sterilization.

This is a specialized form of Pasteurization where liquid food is held at high temperatures of 135-150°C for 2-6 seconds and then rapidly cooled.

Food treated with UHT sterilization can be preserved at room temperature for long periods, such as common Tetra Pak milk. After UHT treatment, it can be stored for a long time without refrigeration.

Under unopened and suitable storage conditions, it can be preserved for 9 or even 12 months.

A longer shelf life also allows the product's sales cycle in the market to be extended, reducing waste caused by expiration.

While UHT technology kills bacteria, it also does a good job of retaining the nutrients in milk, such as protein, calcium, phosphorus, and other minerals, as well as some vitamins. Although a small amount of heat-sensitive vitamins are lost during the sterilization process, overall, Tetra Pak ambient milk still possesses rich nutrition.

The difficulty of UHT sterilization lies in the fact that the sterilized milk needs to be quickly cooled through equipment like heat exchangers, rapidly lowering its temperature to room temperature or lower to prevent microorganisms from multiplying again or the food quality from changing during the cooling process.

Usually, a tubular heat exchanger is used, consisting of a double-set coil made of two stainless steel tubes, utilizing the annular gap between the inner and outer tubes for heat exchange.

Zhao Fusu had equipment obtained from system check-ins, saving him the time for research.

Packaging was also a challenge.

A Tetra Pak is a composite of multiple layers of materials such as paper, aluminum foil, and plastic. Among them, the paper layer provides a certain strength and stiffness; the aluminum foil layer effectively blocks light, oxygen, and moisture to prevent the milk from spoiling; and the plastic layer serves to seal and protect, while also facilitating molding and heat sealing.

Tetra Paks come in various shapes and specifications, the most common being brick-shaped and pillow-shaped.

With its unique aseptic packaging structure, the packaging material undergoes strict sterilization before the milk is filled. Then, in a sterile environment, the UHT-sterilized milk is filled into the packaging and sealed, effectively avoiding external microbial contamination and ensuring the milk can be stored for a long time at room temperature.

After a period of research, Zhao Fusu finally managed to produce the Tetra Pak.

To test it, he wanted to see how long the Tetra Paks he made could preserve milk.

He packaged a batch of milk and planned to open them sequentially after three days, seven days, half a month, one month, three months, half a year, and nine months.

Three days passed in a flash. Zhao Fusu opened a Tetra Pak; he didn't smell anything foul, but instead caught a hint of a slightly scorched milk scent.

This was the current drawback of UHT technology; it would have a scorched taste.

For some products with extremely high flavor requirements, this might be a shortcoming. However, with continuous technological improvements, this situation would be greatly improved.

Seven days passed, and Zhao Fusu opened another carton of milk. It still had that same slight cooked taste, but it hadn't spoiled.

Zhao Fusu knew in his heart that he had likely succeeded.

Nevertheless, Zhao Fusu waited patiently until half a month and then a month had passed. He opened the Tetra Paks again, and it was still the familiar cooked taste.

The corners of Zhao Fusu's mouth curled slightly.

As long as the Tetra Pak's seal wasn't broken, he estimated that preserving it for half a year would be no problem.

This was enough to transport milk from the Southern Desert to the Central Plains for sale.

Once the railway was completed, milk could be transported from the Southern Desert to the Central Plains even faster.

If one were to speak of the most difficult construction project, it was none other than the bridge spanning the Yellow River.

The river surface was not only wide, but the current was also quite rapid.

After measurements, the water depth of the river reached ten meters!

Building a bridge over the ten-meter-deep Yellow River was extremely difficult for the current Great Qin.

The first thing they faced was how to construct the bridge piers; this was a massive challenge!

Whether the location was suitable for building a bridge was also a question.

Generally speaking, before construction, drilling was required. Hollow steel pipes would be driven into the riverbed to examine the rock layers at the bottom.

The bridge piers had to sit on the rock layers to make the bridge more stable.

The current in this section was quite rapid and the water was deep, making it unsuitable for using cofferdams.

Fortunately, when Zhao Fusu checked in, he had obtained the construction drawings and detailed explanations for the Lanzhou Yellow River Iron Bridge, which served as a reference.

The bridge piers were to be manufactured using the Caisson foundation construction method.

First was the production of the caissons, using massive timber to make heavy square frames. The middle of the frames would be filled with heavy materials like silt and sand so they could sink in the water.

Next, the frames were sunk. One by one, the frames were lowered into the water and arranged in sequence until they emerged above the water surface.

The third step was to process the caisson. Once the caisson frames emerged above the water, water pumps were used to drain them, and the gaps between the frames were sealed shut.

The fourth step was to excavate the foundation. The foundation was dug inside the frames to an appropriate depth. Ideally, it had to be dug down to the bedrock.

The fifth step was to place steel reinforcement and pour cement. Steel reinforcement was placed in the excavated foundation, and then cement was poured to form a solid foundational structure.

The sixth step was to place an iron boat. An iron boat was placed on the Caisson foundation to provide further stability and load-bearing support.

The seventh step was to cast the bridge pier. The iron boat was filled with concrete, and after the concrete solidified, the bridge pier was built on top of the iron boat.

Once the bridge piers were built, everything else would be easy.

The Yellow River Iron Bridge used rivets to connect the steel components.

The iron bridge was divided into upper and lower parts.

The upper structure was a through-type steel truss, totaling 109 spans, each with a span length of 45.9 meters, totaling about 5,000 meters.

The roadway was 6 meters wide, with a 1-meter-wide sidewalk on each side, for a total width of 8.36 meters.

Workers would first heat the rivets until they were red-hot, grip them with pliers, place them in the holes, and hold them with a dolly. Workers on the other side would use a pneumatic hammer to quickly rivet them.

Once the rivets cooled, the steel components would be firmly fixed together due to the effect of thermal expansion and contraction.

Before starting such a large-scale project, a small model had to be made first.

Actual construction would only begin after the technology was fully understood.

Even though there was a plan for building the Yellow River bridge, actually constructing it was still very difficult for the construction team.

Zhao Fusu had Cui Wenzi summon bridge experts from all over the country to gather everyone's wisdom to build the Yellow River Bridge.