The second Penang bridge in Malaysia is the longest sea-crossing highway bridge in Southeast Asia, the bridge is 22.5 kilometers long, of which the sea-crossing bridge deck is 16.5 kilometers long, the bridge deck width is 28.8 meters, it is a key development project in Malaysia during the ninth five-year plan period in 2006 ~ 2010, with a total investment of 1.45 billion US dollars.
On October 20, 2008, China Harbour Engineering Co., Ltd. won the bid for the main project of the Penang Second Bridge Project in Malaysia at a price of US$680 million, and the two parties agreed that the construction period was 42 months.
The Penang Second Bridge is the largest Sino-Malaysian joint project and the largest civil project in the previous 20 years, but China has been building the longest sea-crossing bridge in Southeast Asia while using rubber materials that seem to have nothing to do with the construction of the bridge. In the face of the "unexpected move" of the Chinese engineering team, rumors spread at the time, and even played it as the Chinese side cutting corners.
But is this really the case? What difficulties did the Chinese side encounter in building the Penang Second Bridge?
The first sea-crossing bridge in Southeast Asia
Malaysia is a Southeast Asian country with a total area of 330,000 square kilometers, and its territory can be divided into two parts: East Malaysia in the north of Kalimantan Island and West Malaysia in the south of the Malay Peninsula. There are more than 1,000 islands around Malaysia, of which Penang is located on the northwest side of West Malaysia. Covering an area of 293 square kilometres, the island is separated from mainland Malaysia by the Straits on the east side and is famous for its betel nut abundance.
Located at the northern exit of the Straits of Malacca, the Strait of Malacca's status has grown by leaps and bounds due to the prosperity of maritime transportation, and Penang has also risen to become one of the most prosperous shipping centers in Asia. At the end of the 20th century, Penang became the tourist center of Malaysia. As one of the cities in Penang and the second largest city in Malaysia, Penang is a regional and international business and tourism hub.
But the strait in between allows the island to be up to 16 kilometres away from mainland Malaysia, limiting traffic and leaving people to rely on barges. Therefore, in 1982, Malaysia built the Penang Bridge (Penang Bridge) between Penang and Seberang Perai, which is 8,320 meters long and opened to traffic in 1985, breaking the history of no road between Penang and the mainland.
Since its opening, the Penang One Bridge has greatly promoted exchanges between the two places and the economic development of Penang, but the increasing traffic volume has also overwhelmed the Penang One Bridge. In order to further meet the local development needs, the Malaysian government has decided to start the construction project of the Sultan Abdul Halim Bridge (Penang Second Bridge).
In 2000, China Harbor undertook the main project of the Penang Second Bridge under the design-build general contracting model. With a total length of 22.5 km, the Penang Second Bridge is a two-way four-lane highway bridge with a two-way motorcycle lane and a design speed of 80 km/h. The planar alignment of the S-shaped curve and the linear façade of the two undulations make the whole bridge beautiful and comfortable whether it is viewed from a distance or driven.
The Penang Second Bridge is a blend of Malaysian cultural elements, referencing the design of the mosque minaret, and the entire bridge deck is equipped with dense long-pole street lights and LED landscape lighting. When lit up in the night sky, it is lit up and has become a unique landmark of Malaysia.
From the start of construction in 2009 to its official opening in 2014, the US$1.45 billion bridge has become the longest sea-crossing bridge project ever undertaken by a mainland company abroad. There are many domestic participating units, and the construction is difficult, the geological conditions under the sea are complex, and various difficulties are encountered during the construction.
History of difficulties in building bridges
The first is Malaysia's frequently changing temperature environment, and the most worrying thing for building durability is not the highly corrosive environment, a single harsh environment can be specialized, but the frequently changing environment is difficult to prevent.
The Penang 2nd Bridge construction site is in a volatile environment, with the temperature difference between day and night, tidal erosion, strong sunlight, frequent rainfall, and salt changes caused by the intersection of fresh water and high marine salinity all pose a heavy burden on the concrete materials of the bridge.
The construction environment in the tropics is rarely covered by the domestic engineering team, which is not only a huge challenge for us, but also a valuable experience accumulation.
For example, during the construction of the second Penang Bridge, each 100-ton box girder needs to be spliced together in the form of building blocks. Gantry cranes span both sides of the bridge, and then the 100-ton box girder is suspended by a hanging basket system and installed on the main beam, and then the workers use high-efficiency adhesives and high-strength steel cables to fix it. Finally, the hanging basket is propelled by hydraulic cylinders, and each box girder can be built in turn.
In the construction of the box girder, the domestic engineering team poured reinforced concrete in accordance with previous experience. It stands to reason that the box girder poured in this way should be extremely strong and have excellent load-bearing capacity. However, during the construction of the Penang Second Bridge, our box girders repeatedly cracked, and once pressure was applied, they even broke into muck, which obviously did not meet the construction standards.
It was impossible for the Chinese team to use inferior box girder construction, so we began to look for the cause of the problem and investigate all aspects. In the end, it was found that the root cause of the problem was related to the local soil quality of Malaysia.
Malaysia's soil is special, and its soil is used to make concrete, which can not meet the standard requirements in terms of hardness and density, and the perennial high temperature in Malaysia is very easy to lead to thermal deformation of concrete.
After finding the root cause of the problem, the mainland began to import high-strength materials from Japan and China on a large scale. At the same time, in order to reduce the temperature of the concrete, ice cubes are continuously added during the mixing process to cool down, so that the concrete temperature is always kept below 36°C. Cold water pipes are also pre-installed in the steel structure in advance, and the cold water circulation is used to reduce heat.
The problem of the box girder was solved perfectly, but the problem of pile foundation strength also stumped the engineers at the time, forcing us to make innovative changes.
Piling was the first project to build the bridge, and at the beginning of the handover project in Malaysia, it was proposed that the bridge should be able to withstand a magnitude 7 earthquake. This is because Malaysia is not located in the Pacific Rim Seismic Zone, but it is affected by active faults and earthquakes can still occur, such as the 5.9 magnitude earthquake in Sabah in 2015.
In order to ensure the strength of the bridge, we used the current pile driver to insert the steel pipe straight into the sea to a depth of 120 meters, and designed the pile foundation steel casing as a load-bearing column, and the entire bridge has 5,168 pile foundations, the deepest of which is 133.15 meters deep.
In order to reduce the shaking of the bridge during the earthquake, the mainland engineers used rubber materials with high elasticity and non-deformation characteristics for the first time to manufacture a high-damping rubber seismic isolation bearing.
The rubber seismic isolation bearing replaces the traditional steel bearing, and the rigid structure is transformed into a flexible structure, which can more efficiently disperse the seismic energy, whether it is transverse or longitudinal seismic waves, it can ensure full absorption. The unprecedented innovation of the Chinese team also made the Penang Second Bridge fully resistant to a 7.5 magnitude earthquake.
Both ends of the bridge were repaired at the same time, but what should I do if the middle is not right when it is closed? When the second bridge in Penang is closed and docked, there is an error of about 3 centimeters up and down.
A deviation of 3 centimeters may seem inconspicuous, but on a road surface with a speed of 80 kilometers per hour, it is a huge safety risk for a moving car. In order to eliminate the difference in height between the two ends of the bridge, the engineering team injected 100 tons of water into the low deck and 150 tons of water into the high deck. Under the effect of the difference in gravity, the high bridge deck was also continuously pulled down, and finally the bridge deck was successfully aligned.
During the construction of the Penang Second Bridge, a section of the approach bridge undertaken by the Malaysian side collapsed, resulting in the death of four people on the spot. Later, when the Chinese side completed the project, the Malaysian side proposed to re-inspect the entire bridge, and the standard was that the load capacity exceeded 1,200 tons.
Malaysia used 17 trucks with a total weight of more than 595 tonnes, and the horizontal deflection required to be no more than 31 mm during driving. As a result, the Penang Second Bridge built by the Chinese side not only has excellent load-bearing, but also has a maximum horizontal deflection of no more than 25 mm after actual measurement.
In 2014, the bridge was opened to traffic, and the Malaysian government sincerely praised "fortunately chose a Chinese company", and the mainland won the praise of the Chinese company in Malaysia, No.1, and the project won the Luban Prize of China Construction Engineering in 2016. China's international influence will continue to expand with the establishment of large-scale projects.