introduction
China's infrastructure has once again shocked the world. In the vast sea of Malaysia, a majestic bridge rises from the ground.
The bridge spans the Penang Strait, connecting Penang Island with the Malay Peninsula. The bridge tower incorporates elements of Malaysia's religion without compromising on practicality, and looks like the top of a mosque from afar.
The entire bridge is 22.5 kilometers long, and the sea-crossing part alone is 16.5 kilometers, setting a new record for the longest time in Southeast Asia.
The most critical part of the Penang Second Bridge was built by CCCG. The completion of the bridge is another proof of China's identity as an "infrastructure madman".
The construction process not only shows the wisdom of Chinese engineers, but also witnesses the deep friendship between China and ASEAN countries.
So, why did Malaysia build this bridge, and how did Chinese engineers overcome all the odds to accomplish this wonder of the century?
Penang Second Bridge – a complement to the Penang Bridge, but better than the latter
Penang is the third largest economy in Malaysia and the largest per capita GDP in Malaysia. George Town, the state's capital, is also the second largest city in Malaysia.
However, due to poor transportation conditions, the state's economic aggregate has not been able to surpass the top two.
It turned out that the state of Penang was only a federal entity administratively, but not a monolithic body geographically.
The Penang Strait divides the state into two parts, Penang Island and Wellesley Province. The state capital, George Town, is located on the island of Penang.
As a result, the citizens of Wellesley Province had to take a ferry to get to the island to find the state capital. And the boat is swimming on the water, after all, no car runs fast on the ground, and the traffic is very inconvenient.
In order to solve the problem of transportation between the island and the mainland. In 1982, the Malaysian government invested RM800 million to bring in the Korean Hyundai Company.
It took 3 years to build a 13-kilometer-long diagonal bridge across the sea, known as the Penang Bridge, also known as the Penang Bridge.
The completion of the Penang Bridge has greatly improved the traffic situation in the city, which has played an important role in promoting business and tourism.
However, since the beginning of the new century, with the continuous development of Malaysia's economy, the original Penang Bridge can no longer meet the growing traffic demand.
With hundreds of thousands of vehicles a day, the Penang Bridge is overwhelmed. Vehicles are often stuck in traffic for hours before they reach the other side. Especially during rush hour, the traffic is surprisingly high.
As a result, the state government has made a rule that heavy vehicles are not allowed to enter the bridge between 6:30 a.m. and 8:30 a.m. and from 5 p.m. to 7 p.m.
In this context, it is particularly important to build a new sea-crossing bridge to share the traffic pressure of the existing bridge.
But who is going to build the bridge? This time, Malaysia chose China.
At that time, China had gradually replaced Japan and South Korea as the largest infrastructure exporter in Southeast Asia.
The completion of world-class projects such as the Xiamen Bridge, the Donghai Bridge, the Hangzhou Bay Bridge and the Shenzhen-Zhongshan Corridor has created one national business card after another for China.
Moreover, compared with Japan and South Korea, the price of China's bridges is more reasonable and affordable, and the quality is more durable.
Therefore, as a global leader in the field of infrastructure, CCCG has successfully won the bid for the construction of the Penang Second Bridge with its rich experience and advanced technology.
The rock formations on the seabed are hard, and the sea water corrodes day and night
Malaysia turned to China to build the Penang Second Bridge for $6.9 billion, and Chinese engineers faced many challenges at the beginning of construction.
The first step is to lay the foundation for the bridge.
In order to hold the bridge firmly in place on the sea and withstand the terrifying weight of the traffic passing through.
The construction team needed to drill a large hole 120 meters deep in the bedrock of the deepest part of the seabed, drive more than 5,000 piles and 586 bridge piers.
However, the geological conditions of the sea area where the Penang Strait is located are too complex, and the rock layers on the seabed are hard and unevenly distributed. Therefore, piling is also a technical job.
In terms of materials, the construction team chose PHC piles with higher strength to support the load of the bridge.
Compared with ordinary cast-in-place piles, PHC piles are made by advanced pre-tensioning method and two steam curing processes.
The pile has the advantages of high strength, stable and reliable quality, and strong penetration. It is well suited to the geology of the Penang Strait.
In addition, PHC piles do not require much mud during the pouring process, which helps to reduce marine pollution caused by construction.
The trade-off is the higher cost of the materials. Due to the best and most expensive materials used for the Penang Second Bridge, the cost of the whole bridge is slightly higher than that of the Penang Bridge.
In terms of method, the construction team chose a hammering method with a higher degree of prefabrication for piling. Although this method is simple and efficient, it is not less technically demanding. Because once the pile is deviated, it is difficult to pull it out.
Therefore, in addition to controlling the hammering force, the construction personnel also need to accurately grasp the position of the pile sinking, and observe and adjust the anchor position at all times.
After all, in such places, pile sinking is easily affected by tides, wind and waves, and loose cables and causes offside.
The second is the problem of anti-corrosion of bridges.
This is related to the service life of the bridge, and it is essentially a matter of material selection. You must know that a bridge is not finished after the foundation is built, and it needs to be carefully considered for later maintenance.
For example, will the bridge withstand the impact of the waves, and will the concrete and steel structures of the piers break down after years of immersion in water?
As we all know, Malaysia is a tropical country with high temperatures and rainfall. The country's sea pH and diurnal variations in water temperature are very unfriendly to concrete and steel structures.
In addition to the strong erosiveness from the seawater, the tropics also have a characteristic of strong light. Concrete withstands sun exposure during the day and radiates heat quickly at night.
Over time, it will expand and contract. This has an irreversible negative impact on durability, resulting in a shorter service life.
The mainland is a temperate country, so the construction of the sea-crossing bridge is also done in accordance with the temperate climate standards.
So much so that even the most experienced contractor team has never encountered such a tricky environmental problem. Therefore, for the construction personnel, almost every step is an unprecedented attempt.
However, this is also difficult for Chinese engineers. In order to improve the service life of the bridge, they adapted to local conditions and formulated a high-performance concrete.
Compared with ordinary concrete, this kind of concrete contains more fly ash and slag.
After drying, it has high compactness and few cracks. The outer coating of silane can effectively isolate the contact between the concrete and the seawater, and minimize the corrosion hazards.
This high-performance concrete is almost tailor-made for the Penang Second Bridge.
Unfortunately, due to factors such as geological conditions and mineral distribution, the additives required for the preparation of this kind of concrete are not common in Malaysia and cannot be sourced locally.
To this end, the engineering team traveled thousands of miles to import a large amount of fly ash and slag from China. In addition, the mixing of concrete is not always easy, for example, hundreds of tons of concrete are required for each construction.
And these concrete must be ready for use at sea, and cannot be prepared on the shore and then transported to the sea for pouring.
This can make it difficult for the workers. After all, Malaysia is a country where there is almost only summer, and the sun is shining every day as soon as it is time for construction.
Excessive temperatures will lead to the loss of moisture in the concrete and mortar, and the solidification will not be sufficient, so the workers must hold a thermometer in one hand and pray not to exceed 36 degrees while mixing the concrete.
To combat the heat, bags of ice are transported to the floating concrete plant, and water pipes are embedded into the corresponding structure. Water cooling and ice cold work together to continuously cool down the concrete.
The box girder of the Penang Second Bridge
The problem of the foundation has been solved, and how to absorb the shock has become a top priority. It turns out that next door to Malaysia is Indonesia, which has earthquakes every day.
The devastating earthquake in Indonesia in the 90s shocked the people of Southeast Asia. Malaysia is not as unlucky as Indonesia and is located at the junction of tectonic plates.
However, there are still active fault lines within its borders. As the tectonic plate movement intensifies, there will be more and more earthquakes in Malaysia in the future.
Therefore, as early as the beginning of the handover of the project, the Malaysian side required that the completed bridge should at least be able to withstand an earthquake of magnitude 7 or more.
In order to achieve this, in addition to the foundation piles to be secured, the supporting structure that undertakes the bridge deck and substructure is also the key.
To this end, the Chinese side skillfully uses rubber, which can be found everywhere in Malaysia, as the seismic isolation material for the support.
The high-damping rubber is stacked alternately with the steel plate to form the seismic isolation bearing of the bridge, giving full play to the physical properties of the rubber with high elasticity and overcoming rigidity with softness.
It can not only resist the wind, but also not afraid of earthquakes, which can be called the black technology of infrastructure. This was followed by the construction of the bridge deck on the water.
144 cable-stayed cables distribute the weight of the bridge deck to the pylons and pass through the pylons to the foundation, thus preventing the bridge deck from collapsing.
The bridge deck consists of more than 8,000 segmented box girders, spliced together with high-strength adhesives. These box girders are not simple, and each has a multi-ton reinforced frame inside.
Workers first made the frame, and then poured five truckloads of concrete on the frame. After the concrete is dry, a box girder is preliminarily completed.
Because the route of the Penang Second Bridge is not a straight line. So, every box girder is unique. Each segment is only applicable to a specific location.
In order to be perfectly matched, they need to be carefully calculated from the beginning of the design, and even a deviation of 10 millimeters can undo the entire project. So the progress is very slow.
After the box girder is built, the crane is loaded and placed in the predetermined position. The whole process is meticulously detailed, and there are surveyors on the side to monitor it in real time.
The box girders that make up the bridge deck move from both sides of the strait to the middle of the strait, and are pushed along with the cable-stayed cables year after year, day after day. Finally, one day in April 2013, the project entered its final phase.
Unfortunately, however, the last two box girders were not perfectly matched, with a difference of 30 mm. However, when everyone thought that all the efforts they had been working on were going to be in vain.
Engineers came up with a brilliant solution, which was to first secure the two sections of box girders with huge pliers, and then carefully pour the 30-millimeter cracks with tons of concrete.
As it turned out, it worked. A year later, the Penang Second Bridge passed the safety test and was successfully opened to traffic.
epilogue
The completion of the Penang Second Bridge not only demonstrates the advanced level of bridge technology in China, but also alleviates the traffic congestion between Penang Island and Seberang Perai, greatly improving the travel of local people.
After this battle, Chinese enterprises once again proved the leading position of China's infrastructure on the world stage with practical actions, and also let the world see China's responsibility and contribution as a responsible major country.