/kloc-over the past 0/0 years, Wuhan Bridge Science Research Institute has been invited to carry out "physical examination", renovation, maintenance and reinforcement on more than 0/0 super-large bridges, such as Qiantang River Bridge and Jinan Luokou Yellow River Bridge, making them brand-new, durable and effectively extending their service life. On September 20, 2002, Wuhan Yangtze River Bridge, the first bridge of Wanli Yangtze River, completed the deck reconstruction after 46 years of opening to traffic, shouldering the heavy-duty operation in the new century. At the same time, on June 65438+February 1 1 day, the "lumbar bone replacement" operation of the main bridge 1 pier of Nanjing Yangtze River Bridge was successful, and the new bearing of No.35 forged steel was replaced. So far, the Nanjing Yangtze River Bridge has recovered well. This is an effective measure for Hubei and Jiangsu provinces to strictly implement the new national regulations on bridge maintenance, and it is also a good start for Chinese bridges to enter the era of standardized "physical examination" transformation.
One result of many reasons is that the Wuhan Yangtze River Bridge has been opened to traffic for 46 years and suffered 78 ship collisions. It has experienced the flood peaks of 1983 and 1988 with the highest water level, maximum discharge and fastest flow rate in the past two years, and it is still as firm as Mount Tai. This highway-railway dual-purpose bridge with the longest operation time, the largest traffic volume and the largest load in China has created direct economic benefits of10 billion in the past 46 years, and the quality of the bridge body is as always. Fang Qinhan, an academician of China Academy of Engineering and one of the designers and builders of Wuhan Yangtze River Bridge, analyzed that the design, construction and maintenance of Wuhan Yangtze River Bridge are first-class. Good maintenance, service life can exceed 100 years.
The Wuhan Yangtze River Bridge in world famous bridge in 1950s is still a model of high-quality bridges in China. In contemporary China, there are nearly 500,000 special, large, medium and small bridges, of which more than 1 10,000 are "weak" bridges in a class III or IV bad state or with reduced bearing capacity. According to the national statistical data of highway bridges published by the Ministry of Communications, among the existing 230,778 highway bridges, there are 445 1 dangerous bridges in addition to the diseased ones. In Guangdong Province 1870 highway and railway bridges, there are 4,244 new, old, open and concealed bridges. In the past half century, the news media exposed dozens of collapsed bridges in China. According to the analysis of Chinese bridge experts, the causes of "old, weak, sick and dangerous" bridges are: first, ignoring the "physical examination" and maintenance of bridges; Second, the traffic load is increasing, and the original design is not suitable for traffic development; Third, some bridge construction projects were hastily launched, and "achievement projects" and "gift projects" for exploration, design and construction emerged one after another; Fourth, the construction market is not standardized, and "three noes" projects and "bean curd residue" projects occur from time to time; Fifth, the phenomenon of heavy construction and light maintenance is serious. Many reasons, one result, lead to the decline of bridge quality, premature aging of bridges, shortened service life, until "premature death" or sudden collapse.
Standard maintenance is very important. In recent years, the residual pain of the collapse of Chongqing Qijiang Rainbow Bridge is still there. The once brilliant "excellent project" Yibin Nanmen Bridge broke into three sections at 200 1. In addition to the problems of construction quality, excessive fatigue and poor maintenance of bridges are also important reasons for the premature death of bridges. According to relevant data, the daily traffic volume of Yibin Bridge in 2005 was only 7,760 vehicles, while the actual traffic volume had reached 47,000 vehicles before the break. Experts believe that the service life of bridges that have been overloaded for many years will be shortened. Yibin Bridge is poorly maintained, and its service life has been shortened to 1 1 year due to overload operation.
At the accident analysis meeting of Nanmen Bridge, some people thought there was something wrong with the original design. Experts believe that the grade of bridge design is compatible with the grade of highway. The grade of the bridge is decided by the owner, and the design unit only designs according to the owner's requirements. It is also normal for the design to underestimate the traffic flow, and the owner cannot be required to be a forecaster. As long as the maintenance is in place, there will be no broken bridge accident. The curse of Nanmen Bridge began with the sling, and the backward technology in construction could not prevent the sling from rusting. The key lies in the maintenance of the bridge after its completion. Wuhan Yangtze River Bridge is a bridge with steel trusses, beams and rails. After completion, it will be specially maintained by the Bridge Engineering Department of Wuhan Railway Branch. It insists on quarterly inspection and annual inspection, and derusting and painting every year. So far, no steel beam and millions of rivets have rusted. The original design traffic volume of highway bridge deck increased from 50,000 vehicles per day to 954.38+10,000 vehicles. Due to careful care and maintenance year after year, the steel structure of the whole bridge has remained intact for 50 years. However, when Nanmen Bridge was opened to traffic 1 year, there was no comprehensive "physical examination" and routine maintenance could not be done. Regardless of wind and rain erosion and traffic surge, fracture is an inevitable result.
According to international practice, the overhaul period of steel bridges is 10 years, and that of concrete bridges is 30 years. Unfortunately, in our country, except for the highway-railway bridge, which is "examined", maintained and overhauled according to international practice, other bridges are rarely "examined" and maintained, and construction is still emphasized and maintenance is neglected. According to experts, the maintenance cost of bridges in China needs 3.8 billion yuan every year, but the actual investment is only 800 million yuan, only a little more than one fifth. Moreover, the means of maintenance are also very scarce, so it is very dangerous to be satisfied with repairing the bridge deck pavement.
"Physical Examination" Bridge Reconstruction and Repair Since 2002, relevant methods and regulations for bridge detection, maintenance and repair have been issued from relevant state ministries and commissions to transportation departments of various provinces and cities, and funds have been actively raised for the maintenance of existing bridges. Supplementary Provisions on Highway and Bridge Maintenance in Hubei Province was promulgated last year. Wuhan Baishazhou Yangtze River Bridge was completed and opened to traffic in September, 2000, just two years ago, and professional institutions have been entrusted to carry out a "physical examination" of the bridge. In the case of very busy traffic, the Wuhan Municipal Government raised tens of millions of funds to overhaul and renovate the decks of Wuhan Yangtze River Bridge and Jianghan Second Bridge respectively. The construction and management of Beijing-Zhuhai national trunk line attaches great importance to bridge maintenance. At present, the Bridge Testing Center of China Railway Bridge Research Institute has been entrusted to regularly observe several typical bridges in Hubei Province, and experts from the Institute have been entrusted to compile a bridge maintenance manual for daily maintenance.
Bridge "birth and death" is a natural law like human beings. Different bridge designs have different service life according to normal operation. According to the current building materials, construction technology, bridge type structure and construction quality, the longest service life of the most reliable bridge is only 100 years, and the bridge over 25 years will enter the aging period. According to experts' statistics, 40% of the existing bridges in China have a service life of more than 25 years, all of which are "old" bridges. In view of the increasing number of "old, weak, sick and dangerous" bridges in China, bridge maintenance has been paid more and more attention by bridge managers.
Bridge maintenance has attracted more and more attention from all walks of life. Professional institutions for diagnosis and treatment of bridge diseases in Wuhan, Nanjing and other places are listed for business, and more than 40,000 "sick bridges" across the country are expected to recover.
For more information about project/service/procurement bidding, and to improve the winning rate, please click on the bottom of official website Customer Service for free consultation:/#/? source=bdzd