Recently, Guangdong Provincial Communications Group announced good news for the Humen Second Bridge project: the Nizhou Waterway Bridge, a control project of the Humen Second Bridge and the world's longest-span steel box girder suspension bridge, has entered the main superstructure construction. At the same time, the first cable strand of the Dasha Waterway Bridge was successfully erected. The bridge is expected to open to traffic in 2019. Liuzhou OVM Machinery Co., Ltd. (hereinafter referred to as OVM) is one of the participants in the construction of this bridge. The Humen Second Bridge has a total length of 12.89 kilometers, starting from Dongchong Town, Nansha, Guangzhou, passing through Haiou Island, and ending in Shatian, Dongguan. The entire line adopts a bridge scheme, constructed to an 8-lane expressway standard, with a bridge width of 40.5 meters. The design speed is 100 km/h. The project includes two world-class river-crossing bridges over 1,000 meters (the Nizhou Waterway Bridge and the Dasha Waterway Bridge). Among them, the Nizhou Waterway Bridge is a 658+1688-meter double-tower double-span steel box girder suspension bridge. Once completed, it will become the world's longest-span steel box girder suspension bridge, ranking second in the world and first in China among all types of bridges in terms of main span; the Dasha Waterway Bridge is a 1200-meter double-tower single-span steel box girder suspension bridge.
The reporter learned at the site that OVM has been involved in the Humen Second Bridge for a year and a half, and more than a year of construction has not made them slack off in the slightest. Especially since June this year, Guangzhou has experienced sustained high temperatures, and the bridge deck of the Humen Second Bridge is scorching. OVM construction workers, from cutting steel strands, threading cables, tensioning, to welding rebar, every movement they make instantly turns small beads of sweat into a continuous stream, soaking their clothes. Every day from going up the bridge to coming down, their clothes are almost never dry. Like all the technicians and construction workers working on the Humen Second Bridge, they are not afraid of difficulties, fighting high temperatures and scorching heat, striving at the construction site.
OVM entered the site on December 15, 2015, and is expected to complete the work on June 30, 2019.
Su Fengmao, project manager of OVM, said: "Our main construction content on the Humen Second Bridge includes the east tower, east anchorage, middle approach bridge, Haiou Island interchange bridge and ancillary works of the Dasha Waterway Bridge, as well as the prefabrication and assembly of segmental box girders for the entire line. The schedule is tight and the task is heavy, but we are confident to complete our work with high quality. We look forward to the bridge being completed with quality and quantity, and opening to traffic as soon as possible."
Zheng Jin, President of Liugong Group and Chairman of OVM, and his delegation recently visited the Humen Second Bridge to learn in detail about the project progress, construction priorities and difficulties, safety production and other related work, and put forward guiding opinions on future work.
It is understood that the internal tendons used in the Humen Second Bridge are segmental assembly internal tendons (internal prestressing steel strands), all of which are high-strength low-relaxation steel strands with a diameter of Φ15.2mm, nominal cross-sectional area of 140mm2, standard strength of 1860MPa, and elastic modulus of 1.95×105MPa. Internal prestressing is divided into three types: longitudinal prestressing, vertical prestressing, and transverse prestressing. The internal tendons are located inside the concrete structure and fully bonded to the structure, increasing the strength of the concrete structure.
The external tendons are the external prestressing system of the box girder, consisting of external tendons, deviators, anchorage systems, dampers, and protective covers. The external prestressing all uses Φ15.2mm, nominal cross-sectional area 140mm2, epoxy-coated steel strands. The external tendons are located outside the concrete structure and are connected to the structure only at the anchorages and deviator blocks.
In addition, the Humen Second Bridge project also adopted the "replaceable multi-strand finished cable anchorage prestressing anchorage system" led by OVM. According to OVM technicians, this system is based on the comprehensive performance of various anchorage systems, through a breakthrough in design theory, using multi-strand finished cables to replace the traditional steel strand grouting or oil-filling system, resulting in reliable anchorage, superior corrosion protection, simple construction, and low life-cycle cost. Its design, production, testing, and application in multiple projects have shown that all performance indicators meet the requirements of relevant national standards and specifications, and the technology has reached the international leading level. It can provide technical support for large suspension bridge anchorage projects, generate significant economic benefits, and have promotion and application value.
The Humen Second Bridge is an important part of the construction of the Guangdong-Hong Kong-Macao Greater Bay Area and a new important river-crossing channel in the core area of the Pearl River Delta. It is expected to open to traffic in 2019. Once completed, the bridge will become a world-class bridge connecting the east and west banks of the Pearl River, and will also become a milestone bridge showcasing the elegance of China's bridge builders.