土木工程钢结构和钢筋混凝土结构外文文献翻译.docx

1、土木工程钢结构和钢筋混凝土结构外文文献翻译文献信息：文献标题：Recent research and design developments in steel and composite steelconcrete structures in USA（近期美国在钢结构和钢筋混凝土结构研究和设计方面的发展）国外作者：Theodore V.Galambos文献出处：Journal of Constructional Steel Research,2000, 55(1-3):289-303字数统计：英文4718单词，23395字符；中文7671汉字外文文献：Recent research and d

2、esign developments in steel and composite steelconcrete structures in USAAbstract A brief review of the status of structural steel research in the US at the end of the Twentieth Century is presented in this paper to show that while many problems are being solved, there are new and challenging proble

3、ms remaining. The chief impetus for continued research is that provided by natural disasters, such as earthquakes, tropical storms, tornadoes and floods occurring in densely populated urban areas. New materials and new experimental and computational technologies also give rise to new and exciting re

4、search problems. Keywords: Bridges; Buildings; Design; Research; Steel structures; United States of America; Seismic behavior; High-performance materials1. IntroductionThe purpose of this paper is to give a brief overview of the current developments in structural steel research in the US, and of the

5、 future directions that the structural steel engineering research may take in the coming Century. The driving forces of research in this field are the following:new construction methods and construction productsnew materialseconomic considerationsnatural disastersThree of these motivations are commo

6、n to all engineering developments, not just to structural engineering. However, the impetus due to natural disasters is unique to our field. Recent major natural disasters in the US, such as the Northridge earthquake in California and hurricane Andrew in Florida, have spurred much of the current res

7、earch activity.The presentation here is of necessity incomplete, because the author is not aware of all research going on everywhere in the country and there is not enough space in this presentation. The overview is meant to give a general flavor of the research activities, and to show that a signif

8、icant effort is going on in the US. The following is a list of 10 major topics in steel research:1.Limit States Design for bridges2.Monitoring of structural performance in the field3.Design of seismically resistant connections4.Curved girder bridges5.Composite columns with high-performance concrete6

9、.Building frames with semi-rigid joints7.“Advanced Structural Analysis” for buildings8.Repair and retrofit of structures9.Steel structures with high-performance steels10.Cold-formed steel structuresThe next parts of this paper will give brief discussions on some of these topics. Several topics will

10、then be elaborated in more detail. The paper will conclude with a look toward the future of structural steel research.2.Research on steel bridgesThe American Association of State Transportation and Highway Officials (AASHTO) is the authority that promulgates design standards for bridges in the US. I

11、n 1994 it has issued a new design specification which is a Limit States Design standard that is based on the principles of reliability theory. A great deal of work went into the development of this code in the past decade, especially on calibration and on the probabilistic evaluation of the previous

12、 specification. The code is now being implemented in the design office, together with the introduction of the Systeme Internationale units. Many questions remain open about the new method of design, and there are many new projects that deal with the reliability studies of the bridge as a system. One

13、 such current project is a study to develop probabilistic models, load factors, and rational load-combination rules for the combined effects of liveload and wind; live-load and earthquake; live-load, wind and ship collision; and ship collision, wind, and scour. There are also many field measurements

14、 of bridge behavior, using modern tools of inspection and monitoring such as acoustic emission techniques and other means of non-destructive evaluation. Such fieldwork necessitates parallel studies in the laboratory, and the evolution of ever more sophisticated high-technology data transmission meth

15、ods.America has an aging steel bridge population and many problems arise from fatigue and corrosion. Fatigue studies on full-scale components of the Williamsburg Bridge in New York have recently been completed at Lehigh University. A probabilistic AASHTO bridge evaluation regulation has been in effe

16、ct since 1989, and it is employed to assess the future useful life of structures using rational methods that include field observation and measurement together with probabilistic analysis. Such an activity also fosters additional research because many issues are still unresolved. One such area is th

17、e study of the shakedown of shear connectors in composite bridges. This work has been recently completed at the University of Missouri.In addition to fatigue and corrosion, the major danger to bridges is the possibility of earthquake induced damage. This also has spawned many research projects on th

18、e repair and retrofit of steel superstructures and the supporting concrete piers. Many bridges in the country are being strengthened for earthquake resistance. One area that is receiving much research attention is the strengthening of concrete piers by “jacketing” them by sheets of high-performance

19、reinforced plastic.The previously described research deals mainly with the behavior of existing structures and the design of new bridges. However, there is also a vigorous activity on novel bridge systems. This research is centered on the application of high-performance steels for the design of inno

20、vative plate and box-girder bridges, such as corrugated webs, combinations of open and closed shapes, and longer spans for truss bridges. It should be mentioned here that, in addition to work on steel bridges, there is also very active research going on in the study of the behavior of prestressed co

21、ncrete girders made from very high strength concrete. The performance and design of smaller bridges using pultruded high-performance plastic composite members is also being studied extensively at present. New continuous bridge systems with steelconcrete composite segments in both the positive moment

22、 and the negative moment regions are being considered. Several researchers have developed strong capabilities to model the three-dimensional non-linear behavior of individual plate girders, and many studies are being performed on the buckling and post-buckling characteristics of such structures. Com

23、panion experimental studies are also made, especially on members built from high-performance steels. A full-scale bridge of such steel has been designed, and will soon be constructed and then tested under traffic loading. Research efforts are also underway on the study of the fatigue of large expans

24、ion joint elements and on the fatigue of highway sign structures.The final subject to be mentioned is the resurgence of studies of composite steelconcrete horizontally curved steel girder bridges. A just completed project at the University of Minnesota monitored the stresses and the deflections in a

25、 skewed and curved bridge during all phases of construction, starting from the fabrication yard to the completed bridge. Excellent correlation was found to exist between the measured stresses and deformations and the calculated values. The stresses and deflections during construction were found to b

26、e relatively small, that is, the construction process did not cause severe trauma to the system. The bridge has now been tested under service loading, using fully loaded gravel trucks, for two years, and it will continue to be studied for further years to measure changes in performance under service

27、 over time. A major testing project is being conducted at the Federal Highway Administration laboratory in Washington, DC, where a half-scale curved composite girder bridge is currently being tested to determine its limit states. The test-bridge was designed to act as its own test-frame, where vario

28、us portions can be replaced after testing. Multiple flexure tests, shear tests, and tests under combined bending and shear, are thus performed with realistic end-conditions and restraints. The experiments are also modeled by finite element analysis to check conformance between reality and prediction

29、. Finally design standards will be evolved from the knowledge gained. This last project is the largest bridge research project in the USA at the present time.From the discussion above it can be seen that even though there is no large expansion of the nations highway and railroad system, there is ext

30、ensive work going on in bridge research. The major challenge facing both the researcher and the transportation engineer is the maintenance of a healthy but aging system, seeing to its gradual replacement while keeping it safe and serviceable.3.Research on steel members and framesThere are many resea

31、rch studies on the strength and behavior of steel building structures. The most important of these have to do with the behavior and design of steel structures under severe seismic events. This topic will be discussed later in this paper. The most significant trends of the non-seismic research are th

32、e following:“Advanced” methods of structural analysis and design are actively studied at many Universities, notably at Cornell, Purdue, Stanford, and Georgia Tech Universities. Such analysis methods are meant to determine the load-deformation behavior of frames up to and beyond failure, including in

33、elastic behavior, force redistribution, plastic hinge formation, second-order effects and frame instability. When these methods are fully operational, the structure will not have to undergo a member check, because the finite element analysis of the frame automatically performs this job. In addition to the res