A Beautiful Pearl Necklace on the Indian Ocean—Documentary of China-Maldives Friendship Bridge

On July 9, 2018, in the beautiful island country of the Maldives, the builders of the China-Maldives Friendship Bridge successfully completed the final closure of its steel box girders. On the water area between the Male Island and Hulhule Island, three V-shaped piers of the bridge, like three soaring seagulls, connect the two islands.

The challenges and difficulties conquered by the Chinese construction team have successfully demonstrated China's prowess in bridge construction.

The China-Maldives Friendship Bridge is 2000 meters in total length, of which the main bridge covers 760 meters. It is also a six-span (180 meters/span) composite rigid frame bridge, so the most important part of the composition was the hoisting of steel box girders.With a maximum water depth at the construction site of nearly 50 meters, and a wave height reaching up to 5 meters, the sea conditions were extremely poor,the amplitude of a heavy-lift ship could reach up to 1 meter, and its swing amplitude could reach up to 2 meters. It's a challenge for both personnel and equipment to hoist the steel girders to a designated position, increasing the risk of a crash against the bridge deck.

Engineers designed in advance a soft-landing cushioning device: a soft sponge pad which served to secure a soft landing of the steel girders, and increased the security level. During the landing of the steel girders, instructors at the forefront of the construction site would keep a close eye on the patterns of sea waves, and gave instructions when waves started waning. The operator would make response upon the delivery of such instructions and completed a perfect “soft landing” for every section of the steel box girders.

The main bridge of China-Maldives Friendship Bridge has a free height of over 60 meters from the seabed to the top of the deck, and the length of the cantilever of the concrete beam on the upper part of the V-shape pier is 65 meters. Its whole structure resembles a seesaw standing in the sea. Conducting the closure of large sections of steel box girders weighing as much as 600 tons and keeping the balance are also challenges faced by the engineers.“If the balance is broken, the main bridge, if not suffering from disruptive damage, will at least have its beams and piers cracked,” warned Li Ning, deputy chief engineer of the project. Through strict analysis,simulative calculations, and construction control,engineers made 26 individual weight adjustments in the 95-meter-long incremental launching process.That meant making a weight adjustment at an average of every 3.5 meters, with a total adjusted weight of more than 1,000 tons.

Monitoring data indicates that the swing amplitude of the cantilever of the main bridge could reach up to 3 centimeters, and under the effect of large temperature differences, the length difference of the joints of the closure could vary 2 centimeters.How to ensure the precision of the bridge's closure under such conditions was a big problem faced by the bridge builders. The construction team employed the method of lowering the large sections of steel box girder and cut them multiple times to meet the precision requirement of the closure. It took 900 days for the Chinese and Maldivian engineers to succeed.

Ibrahim, a 70-year-old local man, commented excitedly, “It is an extremely exhausting journey to Hulhule Island or Male Island by boat if you encounter bad sea conditions. From now on, we can go to the airport by car. The bridge will bring convenience from generation to generation.”

中馬友誼大橋全景俯瞰A Panorama of the China-Maldives Friendship Bridge

串起印度洋上的美麗“珍珠”——援馬爾代夫中馬友誼大橋紀(jì)實(shí)

2018年7月9日，在風(fēng)光旖旎的馬爾代夫，一座由中國中交二航局承建的大型橋梁工程——援馬爾代夫中馬友誼大橋，成功合龍。在首都馬累島與機(jī)場島之間的海面上，這座大橋的三個(gè)V型墩像三只海鷗，展翅飛翔，將兩座島緊緊地聯(lián)結(jié)在一起。

中國團(tuán)隊(duì)這次建橋過程中經(jīng)歷的挑戰(zhàn)，有力地證明了中國建橋力量的實(shí)力。

中馬友誼大橋全長2000米，主橋長760米，為六跨180米疊合鋼構(gòu)橋，所以鋼梁合龍是重要環(huán)節(jié)。在最大水深50米、涌浪最大高度5米、船舶上下升沉幅度1米、左右擺幅超過2米的情況下，如何把鋼箱梁吊裝到位，是對技術(shù)和裝備的嚴(yán)峻挑戰(zhàn)。一不小心，極可能造成鋼梁與橋面碰撞受損。

2018年6月24日，援馬爾代夫中馬友誼大橋主橋20號墩至21號墩之間的鋼箱梁正在頂推。Installation of steel box girders between Pier 20 and Pier 21 of the main bridge of the China-Maldives Friendship Bridge on June 24, 2018

2018年6月29日，援馬爾代夫中馬友誼大橋最后一個(gè)鋼箱梁合龍段施工準(zhǔn)備工作。On June 29, 2018, engineers preparing to conduct the final closure of steel box girders for the China-Maldives Friendship Bridge

工程師們提前設(shè)計(jì)出一套鋼梁著陸緩沖裝置，讓鋼箱梁下落后就像落在一個(gè)柔軟的海綿墊上，有效增強(qiáng)了安全性。在鋼梁下落過程中，一線起重指揮人員不斷把握海浪起伏規(guī)律，實(shí)現(xiàn)了每節(jié)鋼箱梁的完美軟“著陸”。

中馬友誼大橋主橋墩凈高超過60米，左右混凝土梁懸臂各長65米，看起來就像海中的蹺蹺板。如何實(shí)現(xiàn)重達(dá)600噸的大節(jié)段鋼箱梁從橋面上頂推合龍，掌握好橋兩端承重平衡，這又是一大挑戰(zhàn)。“若橋體失衡，輕則造成梁體和墩身開裂，重則導(dǎo)致主橋傾覆性破壞。” 項(xiàng)目常務(wù)副總工李寧指出。在鋼梁95米的頂推行程中，累計(jì)進(jìn)行了26次配重調(diào)整。鋼梁平均每前進(jìn)3.5米，就進(jìn)行一次配重調(diào)整，累計(jì)調(diào)整重量達(dá)1000余噸。

監(jiān)測發(fā)現(xiàn)，主橋懸臂梁體在強(qiáng)涌浪中的晃動(dòng)幅度達(dá)到3厘米；再加上晝夜溫差變化，合龍口的長度變化接近2厘米。在這樣的情況下，要保證大橋的合龍精度，要將配切后的焊縫寬度控制在1厘米以內(nèi)，誤差不超過5毫米，又是一大挑戰(zhàn)。建設(shè)團(tuán)隊(duì)采用“大節(jié)段鋼梁橫向錯(cuò)位下放、分次配切就位合龍”的新方法，實(shí)現(xiàn)了毫米級誤差合龍。中馬建設(shè)者奮戰(zhàn)900多天，終于迎來這一重大勝利。

年近70的易卜拉欣老人激動(dòng)地說：“如果海況不好，坐船到機(jī)場島或胡魯馬累島實(shí)在太難了。今后，可以打車過橋直達(dá)對岸，世世代代都方便了。”