外文翻译钢板包裹的钢筋混凝土柱受冲力影响下的性能.docx

1、外文翻译钢板包裹的钢筋混凝土柱受冲力影响下的性能中文7700字,5400单词，2.5万英文字符出处：Griffith M C, Wu Y F, Oehlers D J. Behaviour of Steel Plated RC Columns Subject to Lateral LoadingJ. Advances in Structural Engineering, 2005, 8(4):333-348.原文Behaviour of Steel Plated RC Columns Subject to Lateral LoadingGriffith M C, Wu Y F, Oehlers

2、 D J.Abstract: The main focus of this paper is to describe the behaviour of RC columns that areretrofitted with an alternative technique to “jacketing” or wrapping. This new technique consists of attaching steel plates to the tlexural faces of a concrete column using bolts. It is envisaged that this

3、 technique would be suitable primarily for columns having rectangular cross-sections and in situations where lateral loading induces predominately a single plane of bending (as opposed to biaxial bending). Effectiveness of this new technique has been demonstrated by experimental testing and numerica

4、l simulations. This paper studies the mechanism of the new retrofit scheme, how it works, and the behaviour of columns retrofitted using such a scheme, as well as the important parameters that affect the response of the retrofitted columns. This study forms the basis for the design of the plate retr

5、ofitting system.Keywords: reinforced concrete, columns, numerical model, retrofitting, partial interaction, slip.1. INTRODUCTIONTheoretical and experimental studies have demonstrated that external jacketing can be highly effective in preventing existing columns from premature shear, lapspltce or fle

6、xural failure in the case of circular columns. Therefore, this kind of retrofitting work has already been widely used in engineering (Chai et al. 1991, 1994; Priestley et al. 1994a,b).However,it is not quite as clear-cut for rectangular RC columns where the success of the retrofit procedure depends

7、onthe degree to which jacketing increases confinement. For example, Park (2001) states “A rectangular thin steel jacket would not be so effective, due to the sides bowing out when dilation of the concrete occurs during a major earthquake, resulting in confinement applied mainly in the column corners

8、”. Although rectangular jacketing can still be effective in certain circumstances, the relative poor performance of rectangular jackets in confining the concrete core has been experimentally verified (Chai et al. 1990; Mirmiran et al. 1998, 2000; Pessiki et al. 2001) and Theriault and Neale (2000) c

9、oncluded that the confinement effectiveness by FRP (Fibre Reinforced Polymer) wrapping is far less for rectangular columns than it is for circular columns.Efforts to improve the confinement effectiveness rectangular jackets have been reported in the literature. One technique was to enhance the out-o

10、f-plan flexural stiffness of the jacket by using additional stiffeners in the cross-section. However, test results showed that the improvement was not satisfactory (Chai et al. 1990). The use of anchor bolts to enhance the confinement from rectangular steel jacket was shown (Aboutaha et al.1996) to

11、also provide limited improvement. Another technique used for rectangular column jacketing employs an elliptical shaped jacket. Research works has shown that this technique is highly effective for retrofitting RC columns with rectangular shaped cross-sections (Priestley et al. 1994b, 1995; Teng and L

12、am 2002). Nevertheless, changing square or rectangular shaped column sections to circular or elliptical sections by circular or elliptical jacketing is not always desirable or practical in engineering, especially where space is limited as in building structures.There has been much research into the

13、use of advanced composite materials such as fiberglass and carbon fiber jackets/wrapping to replace steel jackets in recent years (Katsumata et al. 1988; Saadatmanesh et al.1994, 1996; Priestley and Seible 1995; Seible et al. 1997; Xiao and Ma 1995, 1997;Mirmiran and Shahawy 1997; Hanna and Jones 19

14、97; Xiao et al. 1999; Liu et al. 2000; Pantelides et al. 2000; Karbhari 2001; Theriault and Nealc 2000; Yao et al. 2001; Lau and Zhou 2001; Pessiki et al. 2001; Parvin and Wang 2001; Lam and Teng 2003a,b; Teng and Lam 2004). Nevertheless, FRP jackets like their steel counterparts, rely on their abil

15、ity to increase the confinement of the concrete column so that its material behaviour beyond the peak compressive stress point is improved.In contrast to “jacketing” retrofit schemes, the form of composite plating developed by the authors is a new concept for retrofitting rectangular RC columns. It

16、works, essentially, by delaying the onset of concrete crushing through the addition of external steel plating that acts only in compression on the flexural faces of the concrete column. By delaying concrete crushing, additional curvature can be sustained by the column before substantial loss of stre

17、ngth occurs, resulting in substantially increased displacement / drift capacity. Details of the new retrofit scheme are described in the next section. (Note: plate buckling of side-plated concrete beams can be prevented through judicious choice of plate thickness and bolt spacing (Smith et al. 1999)

18、. It is not a focus of this paper and will not be discussed further.)2. RETROFIT SCHEME BY PARTIAL INTERACTION PLATINGA schematic of the new scheme is given in Figure l where a length of column between its end and midheight is shown. Steel plates in the shape of an “L” (as in Figure l (a) are bolted

19、 to both the tension and compression faces of the column and also to the foundation or beam / slab (Figure l (a) and l (d). The novel aspect of this retrofit solution is that the plate on the tension face can be made to attract very little tension force, in the plastic hinge zone at the base of the

20、column, by positioning the bolts away from the joint (Figure l (b), l (c). On the other hand, the plate on the compression face will attract significant compressive force due to the high compression stiffness of the plates end bearing condition (Figure l (b).Thus, the crushing of concrete is delayed

21、 substantially not by increased concrete compressive strength due to increased confinement but rather by virtue of transferring the compression load from the concrete to the steel plate. This has the potential to significantly increase either the strength or the ductility or both of a concrete colum

22、n.The motivation for this alternative retrofit concept is that substantially improved confinement through jacketing is not always achievable for rectangular cross-sections. Further many concrete frame structures in low to moderate earthquake hazard regions have been designed predominately for gravit

23、y and wind loading but may have insufficient levels of displacement ductility to withstand significant earthquake shaking. In many instances, the columns have sufficient shear strength for the columns to reach their ultimate moment capacity. In the present work, it has been assumed that column flexu

24、re occurs primarily in asingle plane. For example, bridge piers whose flexure in the longitudinal direction is restricted due to the axial stiffness of the bridge deck and displacement constraints of the bridge abutments. In addition, it is not unusual to have columns in a building structure partici

25、pating in moment frame action under lateral loading only in a single direction. For all of these situations, it may be feasible to consider retrofit only for uni-directional loading rather than bi-directional loading.The effectiveness of the new retrofit scheme has been demonstrated experimentally (

26、Wu et al. 2003). Abrief description of the testing is provided here. The test configuration is illustrated in Figure 2 (a) with the axial load N =360 kN being applied in “force control” mode and the lateral load F being applied in “displacement control” mode. In order to get two tests from each spec

27、imen, one end was temporarily strengthened by sandwiching the column between large steel channel sections (Figure 2 (b) so that the deformations due to the loading occurred only in the opposite end. The reinforcement details for the columns consisted of four 16 mm deformed bars and 10 mm stirrups at

28、 100 mm spacing as shown in Figure 2 (c). The retrofit scheme details for the test columns (given in Table 1) consisted of bolting either 6 mm or 12 mm thick steel plate onto the tension and compression faces of the columns. The bolts were adhesively attached to the column using Hilti HIT-HY 150 adh

29、esive. The interaction or shear between the bolts and the steel plate was transmitted by bearing.The holes in the steel plate were 0.2 mm greater than the diameter of the bolts. The steel plate just sat on the column base and no other measure was used to prevent local concrete crushing at base and b

30、uckling of steel plate. For more details of the testing and design of the plate and bolting pattern refer to Wu (2002) and Wu et al (2003).Plots of the lateral load F versus sidesway deflection are presented in Figure 3 andthe results are summarized in Table 2. It should be noted that a more useful,

31、 non-dimensional, variable for expressing the sidesway response is in terms of “drift”, defined here as divided by the column height of 1.218 m. The drift response is also shown in Figure 3 on the top horizontal axis. To compare the response of the three columns, it is convenient then to use displac

32、ement ductility, defined by Eqn 1, = u y(1)where yis the yield displacement (the point where the tensile reinforcement first yieldsand the maximum strength is reached), andu is the lateral displacement at the point wherethe lateral resistance force equals 80% of the maximum lateral force. The displa

33、cement ductility factors for the three curves in Figure 3 are listed in Table 2 where it can be seen that both the plated columns had greater displacement ductility than the unplated column. Similar behaviour was observed in the cyclic loading tests (Figure 4) where the 6 mm plated column (4ACP6) was significant