Based on the formulation process and background of Japanese bridge wind-resistant design code, this paper analyzes the wind-resistant design code that constitutes the bridge wind-resistant design code system, and points out that Japanese wind-resistant design code has the characteristics of strong operability and perfect system, so as to provide reference for the formulation and development of Chinese bridge wind-resistant design code.
I. Introduction
With the rapid development of transportation, more than 20 long-span bridges with main spans over 400m have been built in China since the end of 1980s. Cable-stayed bridges and suspension bridges are sensitive to the action of wind, and the action of wind, especially dynamic action, often becomes the controlling factor in the design and construction of these two bridges. China's current General Code for Design of Highway Bridges and Culverts (JTJ02 1-89) stipulates the static wind load, but it is not applicable to long-span bridges, and the wind resistance checking calculation in dynamic wind resistance design and construction of bridges is even blank. Therefore, with the active support of domestic units and experts engaged in bridge wind resistance research, this paper summarizes the achievements of bridge theoretical research and wind tunnel test in China for more than ten years, and refers to and absorbs some achievements in other countries' bridge wind resistance design codes and standards. It took three years to compile the first guiding document for wind resistance design of long-span bridges in China-Guide for Wind Resistance Design of Highway Bridges (hereinafter referred to as Guide).
Over the past four years, the Guide has played a great guiding role in the wind-resistant design of long-span bridges. However, due to the action of wind and the complex response of bridges to wind, the depth and width of the guide can not completely solve the problems involved in the wind-resistant design and checking calculation of bridges. In addition, the new insights gained from the further study of bridge wind resistance in recent years and the increasingly rich experience accumulated in practical projects should be included in order to carry out bridge wind resistance design more conveniently, effectively and normatively. 1997, the Ministry of Communications initiated the compilation of the industry standard "Code for Wind-resistant Design of Highway Bridges" (hereinafter referred to as "Code") in People's Republic of China (PRC) and China. Although the compilation of the Code is nearing completion, it will take some time for its promulgation and implementation. Although the "code" is a step forward than the "guide", the construction of long-span bridges in China is in the ascendant, and the construction of larger-span bridges in worse wind environment is in the early stage of preparation. Moreover, the Code can not completely solve all the problems in the wind-resistant design of bridges, nor can it cover all the different spans and differences. As a close neighbor of China, Japan is often attacked by strong typhoons. Since the 1960s, many long-span sea-crossing bridges, represented by Shikoku Bridge in Honshu, have been built one after another, and the wind-resistant design standards of bridges have been improved day by day. Taking the Japanese code for wind-resistant design of bridges (using Japanese characters without affecting the meaning) as an example, this paper expounds the change and system of the code for wind-resistant design of bridges, in order to provide some reference for the compilation and development of the code for wind-resistant design of bridges in China.
Secondly, the change and background of Japanese bridge wind-resistant design standards.
In the past 40 years, Japanese bridge wind-resistant design standards have undergone various changes and gradually formed a perfect system.
From 65438 to 0959, Japan's Ministry of Construction and the state-run railway began to organize the research work of the Shikoku Bridge in Japan (hereinafter referred to as the Shikoku Bridge). 196 1 year entrusted the research work to Japanese non-governmental organizations, and established the technical investigation Committee of this four-bridge in the non-governmental organizations. Under this committee, various subcommittees have been set up, and the Subcommittee on Wind-resistant Design headed by Professor Ping Bidun of the University of Tokyo started its work in 1963. At that time, the insights gained from the reflection on the old Tacoma Bridge in the United States have been applied to the new Tacoma Bridge, the Wako Bridge in Japan and the bridges in Britain. There are a large number of long-span bridges in Japan which are very important for wind resistance, and there must be a unified standard. Therefore, the Guidelines and Instructions for Wind-resistant Design of Shikoku Bridge in Honshu (1964) (hereinafter referred to as "Guideline 64") was formulated, and later revised to "Guidelines and Instructions for Wind-resistant Design of Shikoku Bridge in Honshu (1964)".
1970 established the Honshu Shikoku Liaison Bridge Commune (hereinafter referred to as the Commune), which is responsible for the main work of investigation and research, but the work entrusted to non-governmental organizations is still completed by non-governmental organizations, and a wind-resistant research committee headed by Dr. Okubo from the Institute of Civil Studies of the Ministry of Construction was established, whose main tasks are ① to formulate the wind-resistant design benchmark for accommodating and absorbing the new research results after "Indicator 67". (2) Establish the wind tunnel test benchmark. ③ Observe the wind-resistant experimental bridge and evaluate the accuracy of the wind tunnel test. The results of this Subcommittee's work are as follows: wind-resistant design criteria (1972), wind-resistant design criteria (1975) and wind-resistant design criteria (75). After revision, it was changed to "Design Basis for Wind Resistance of Honshu Shikoku Contact Bridge (1976)" (hereinafter referred to as "Basis 76") and "Wind Tunnel Test Basis for Honshu Shikoku Contact Bridge (1976)" (hereinafter referred to as "Test Basis 76"). Among the four bridges, Yindao Bridge, Dawumen Bridge and Lazhu Bridge, the work of the Wind Resistance Research Committee led by Dr. Okubo ended with 1975.
Although "Benchmark 76" was compiled on the basis of the latest achievements and opinions of wind resistance research at that time, some new phenomena and problems were also found in the implementation process. Because there is not enough time for research, we have to take a slightly richer safety reserve in the wind-resistant design of bridges.
1976, in order to deal with the problems in the implementation of "benchmark 76" and "test benchmark 76" and analyze the observation data of the wind-resistant experimental bridge, a wind-resistant research subcommittee headed by Professor Tong Nei-gong of Central University was established among the people. From the late 1970s to the early 1980s, it was during the discussion and research period that the mid-span of the Akashi Strait Bridge was changed to nearly 2,000 m, so it was a very important subject to ensure the wind resistance of the Akashi Strait Bridge. During the period of 1982 ~ 1987, according to the wind resistance research results of various design schemes of the Akashi Strait Bridge and some new opinions on the wind resistance of the bridge, the Subcommittee on Wind Resistance Research compiled the Akashi Strait.
1989, the investigation of the fourth bridge was transferred from the society of civil engineering to the marine bridge investigation meeting, and at the same time, the weatherproof committee headed by Professor Li Xiong Miyata of Yokohama National University was established, and the "Akashi Essentials (Case) 88" was partially revised, and the "Essentials and Interpretation of the Windproof Design of Akashi Strait Bridge" (1990) was formulated (hereinafter referred to as Akashi Essentials 90) At the same time, the original Test Essentials 76 was supplemented and revised, and the Wind Tunnel Test Essentials of Akashi Strait Bridge (1990) (hereinafter referred to as "Akashi Test Essentials 90") was formulated.
While defining "90 Essentials of Akashi" and "90 Essentials of Akashi Test", the Committee formulated "Design Basis and Interpretation of Tail Road, Modern Governance and Wind Resistance (1994)" (hereinafter referred to as "Tail Road, Modern Governance and Laidao Bridge"). The Committee also summarized the full-bridge model test of large-scale wind tunnel and Akashi Strait Bridge after "Essentials of Akashi". The wind-resistant design benchmark (case) (1998) (hereinafter referred to as benchmark (case) 98) has been formulated. The following is the comparison between the construction of the fourth bridge and the formulation of the wind-resistant design benchmark.
1959 provincial and Japanese state-run railway construction; Investigation and study on the construction of the fourth bridge in Pingjing town.
1963 "Pointer 64" and "Pointer 67" were formulated by the civil society wind-resistant design committee.
1970, Sigong Group was established.
197 1 A civil society wind-resistant subcommittee was established in Okubo.
Wind-resistant experimental bridge 1972 ~ 1974 observation datum 72
1975 "Benchmark 75" and "Benchmark 76" were formulated by the Subcommittee on Wind Resistance Research of non-governmental organizations.
1976 Daming Gate Bridge begins "Test Benchmark 76"
1977 yindao bridge started.
1978 erdaosakou line started.
1980 "test points 80" real bridge vibration observation
1984 vibration test of real bridges (Dawumen Bridge, Nanbei Zanseto Bridge, Kamishishima Bridge, Oshima Bridge, etc.). )
1988 Construction of Akashi Strait Bridge and Laidao Bridge "Akashi Essentials (Case) 88"
1989 investigation meeting of ocean bridge, establishment of wind resistance committee, large-scale wind tunnel test of Akashi Strait Bridge "Akashi essentials 90" Miyata Li Xiong.
1990 ~ 1997 "90 essentials of open stone test" for large-scale wind tunnel test of duoluo bridge
Large-scale wind tunnel test of Laidao Bridge "Tail Road, Benchmark 94"
1998 "Benchmark (Case) 98" is the completion of Akashi Strait Bridge.
1999 completion of Jinzhi line of Tail Road
Third, the characteristics of each wind-resistant design benchmark
The compilation of wind-resistant design criteria and the construction of long-span bridges restrict and promote each other. The characteristics of each wind-resistant design benchmark constituting the bridge wind-resistant design benchmark system are as follows:
1. "Pointer 64"
(1) Set the basic wind characteristics considering factors such as height distribution.
(2) The basic wind speed setting method considering the return period is proposed.
(3) Determine the check wind speed of self-excited vibration as 1.2 times the design wind speed.
2. "pointer 67"
(1) It is determined that the basic wind speed in Wumeng Strait is 50m/s, and that in other areas is 45m/s..
(2) Consider 100 and 150 years.
(3) The duration of wind speed during construction is 30 years.
(4) According to the relationship between turbulence and structural size, correct the design wind speed.
(5) According to the wind speed, the angles of attack considered in the design are 5 and 10.
3. "Benchmark 72"
(1) defines the flow of wind-resistant design.
(2) The basic wind speed is divided into four regions, and the return period is 150 years.
(3) The design wind load is revised considering the gust response.
(4) The benchmark and allowable error of wind tunnel test are set.
(5) The angle of attack is 7.
4. "Benchmark 75"
(1) The basic wind speed is divided into five areas.
(2) Modify the height distribution of wind speed
(3) Correcting the allowable stress increase coefficient when considering wind load.
(4) Determine the wind load during nuclear power construction.
(5) The main tower model test is added to the wind tunnel test benchmark.
5. "Benchmark 76"
(1) In order to keep consistent with the design basis of the superstructure, the calculation method of wind load is partially modified.
(2) In "Wind Tunnel Test Essentials 80", the contents of model making and test results sorting are added.
6. "Akashi Essentials 90"
(1) Special Datum for Akashi Strait Bridge
(2) The basic wind speed is changed to 46m/s.
(3) The influence of gust response is changed from the correction of wind speed to the correction of wind load, and the gust response analysis method is added in the appendix.
(4) Structural damping can be divided into bending damping and torsion damping.
(5) The specified gust response should be analyzed and checked.
(6) Check whether the angle of attack is 3.
(7) The time variation of wind speed is considered in the self-excited vibration test.
(8) The wind tunnel test of the main tower after the bridge is completed is added to the wind tunnel test essentials.
7. Wei Jin Daozhi Benchmark 94
(1) Special wind-resistant benchmark for tailrace and Jinzhi line.
(2) Set the basic wind speed, the height distribution of wind speed and the turbulence intensity of the tailrace route.
(3) Wind load correction based on gust response analysis results.
(4) Increase the inspection of wind and rain vibration of cables.
8. Benchmark (Case) 98 summarizes the experimental research results of large-scale wind tunnel full-bridge model.
Four. Concluding remarks
In addition to the above-mentioned wind-resistant design criteria applicable to long-span bridges, Japan has also compiled the Wind-resistant Design Guide for Highway Bridges in 199 1. Over the past 40 years, with the construction of bridges in Japan, a complete set of wind-resistant design criteria system for bridges has been formed. In the process of compiling design benchmarks, civil society has played a huge role. Each benchmark has a different time and background, but it is not necessarily that the new benchmark is more perfect and advanced than the old benchmark. Each benchmark is formulated by comprehensively considering different factors such as different bridge spans, different regions, different topographic features of bridge sites, different requirements of wind tunnel tests, etc., and has strong operability. Wind tunnel test is an indispensable means for bridge design, detection and research. In order to correctly evaluate the results of wind tunnel test,