On August 27, 2021, the road deck of Padma Bridge in Bangladesh, which was constructed by China Railway Bridge Bureau and designed by China Railway Bridge Institute, was completed.

The 6.15km steel dragon unveiled

The main bridge of Padma Bridge is 6.15 kilometers in length. It is a double-deck steel truss bridge with a two-way four-lane highway on the upper layer and a single-track railway on the lower layer. The upper road deck is composed of 2,917 decks. Each deck is 21.25 meters wide and has two specifications of 2 meters and 2.15 meters in length. Each deck weighs about 60 tons.

In order to quickly erect the bridge deck, the project department adopts the 900-meter integrated prefabricated glue assembly technology, that is, the bridge deck prefabrication is completed on the shore, and then the bridge deck is lifted to the pier by special equipment such as floating cranes through waterway and bridge deck transportation. The on-site installation work is completed by the board racking machine.

Solve technical problems of bridge deck erection

The construction process of the bridge deck is complex and the technical difficulty is high. The steel girder of the main bridge is 150 meters long and weighs about 3,000 tons. The installation accuracy must be controlled within 2 mm. Due to the temperature difference, the position of the bridge deck can change up to 20 mm within a few hours. In order to ensure the extremely accurate measurement and positioning, the field technicians use the relative positioning method and use the steel beam as the benchmark to ensure that the installation accuracy reaches the standard through real-time measurement and calculation.

The project department has successively invested 4 sets of highway plank erecting machines in segmented operations, and realized the functions of "gluing, clearing, and stretching" simultaneously with the help of an integrated platform. Using the method of cross anchoring, the original three-tensioning and three-time grouting technology was improved to three times. Stretching once to squeeze. Through such a series of innovative measures, resource allocation adjustments, construction technology and sequence optimization, the builders reduced the time required for a single round of grouting from the initial 3 to 4 days to about half a day, and the erection speed of highway bridge slabs has also been reduced from 4 days a day. The block is raised to 17 blocks.

Responding to the effects of severe weather

In addition to technical difficulties such as heavy lifting tonnage, high lifting height, and high risk of high-altitude operations, the builders also have to deal with the challenges brought by adverse weather such as seasonal squall winds and heavy rains. For this reason, the project department held several special meetings to continuously optimize the construction plan and control every construction link in the whole process.

The builders raced against the flood, opened the bridge deck transportation channel in advance, and changed the transportation mode of the last two hundred road slabs from water transportation to bridge deck transportation, ensuring the construction progress and safety of the bridge.

Take multiple measures to prevent epidemics in construction

Since March 2021, Bangladesh's new crown pneumonia epidemic has repeated, and the number of confirmed cases has reached 1.38 million. Faced with the challenge of the epidemic, the project department took multiple measures to ensure that the construction and epidemic prevention were correct.

In July 2021, Dhaka will close the city, which coincides with the peak period of bridge road slab erection. The surge in cement consumption has led to a shortage of cement stocks. In order not to affect the construction, the project department communicated and coordinated with various parties to obtain a green channel for cement supply. Since June, the erection of the highway bridge deck of the main bridge of the bridge has accelerated at an average rate of 100 yuan per month and was completed ahead of schedule by the end of August.

In terms of epidemic prevention and control, the project department actively responded to the call of the Chinese Embassy in Bangladesh to vaccinate Chinese employees in Bangladesh with inactivated new crown pneumonia vaccines through the "Spring Miao Action". In addition to daily epidemic prevention measures such as temperature measurement, disinfection, and regular distribution of masks, the project department has also established 33 dormitories for centralized placement of Bangladeshi employees. The resident sites are closed and managed, and free boarding and lodging are provided.

The Padma Bridge in Bangladesh is one of the important “Trans-Asian Railway” passages connecting China and Southeast Asia. Affectionately called the "Bridge of Dreams".

After the opening of the Padma Bridge, the 21 districts in southern Bangladesh and the capital Dhaka can be connected to realize the connection of north-south highways and railways, thereby forming a new traffic artery and ending the thousands of years of ferrying history on both sides of the Padma River. , Shortening the original seven or eight hours of crossing the river to 10 minutes. According to estimates, the opening of the bridge will bring about 1.2% growth in Bangladesh's GDP every year.

Keywords: One Belt One Road, overseas projects, engineering news

At present, the bridge deck of Padma Bridge has been fully connected. The next step is the opening of the whole line. Let us look forward to it. Editor/Tian Zengpeng