摘要:

AbstractA new vehicle model and the partial bridge model were used to study the dynamic interaction between an open deck steel truss bridge and a moving freight train. The responses in terms of dynamic stresses in certain critical members in the bridge were generated to predict their fatigue lives by using a reliability‐based methodolog

ISSN:0098-8847    

DOI:10.1002/eqe.4290130602

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe seismic response of light secondary systems in a building is dependent on the response of the primary structural system to the seismic ground motion with the result that very high accelerations can be induced in such secondary systems. This response can be reduced through the use of aseismic base isolation which is a design strategy whereby the entire building can be decoupled from the damaging horizontal components of seismic ground motion by the use of some form of isolation system.The paper presents a theoretical analysis of the response of light equipment in isolated structures and a parallel experimental programme both of which show that the use of base isolation can not only attenuate the response of the primary structural system but also reduce the response of secondary systems. Thus, the design of equipment and piping in a base‐isolated building is very much simpler than that for a conventionally founded structure: inelastic response and equipment‐structure interaction need not be considered and multiple support response analysis is rendered unnecessary.Although an isolation system with linear elastic bearings can reduce the acceleration of the structure, it may be accompanied by large relative displacements between the structure and the ground. A system using lead‐rubber hysteretic bearings, having a force‐displacement relation which is approximately a bilinear loop, can reduce these displacements. A parallel experimental programme was carried out to investigate the response of light equipment in structures isolated using lead‐rubber bearings. The experimental results show that these bearings can dissipate energy and limit the displacement and acceleration of the structure but are less effective in reducing the accelerations in the internal equipment.The results of both the analysis and the tests show that base isolation is a very effective method for the seismic protection of light equipment items in

ISSN:0098-8847    

DOI:10.1002/eqe.4290130603

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThis study shows that, for Northwest Europe, an intraplate region of subdued seismicity, a comparatively simple attenuation model is adequate to predict quite accurately the fall‐off of intensity with distance. The analysis shows that focal depths determined from macroseismic data are confined in the upper 25 km, and that shallow shocks attenuate far more rapidly than deeper events. There is no evidence for a regional variation of the absorption coefficient, which, together with the coefficient of geometric spreading, is a function of depth. Also, the intensity factor b, which is usually taken to be equal to 3, is a variable and a function of the energy absorption at the epicentre. It is shown that magnitudes can be predicted accurately by use of one or preferably by more isoseismal radii calibrated against re‐assessed instrumental magnitu

ISSN:0098-8847    

DOI:10.1002/eqe.4290130604

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractAn efficient method for accurately modelling the gradual opening and closing of joints in two‐dimensional slabs and arches has been devised. The method is used in computing the earthquake response of an arch which is a representative horizontal cross‐section of a concrete arch dam. Responses of the arch with and without joints are compared to assess the effect of joint opening. An extension to three‐dimensional arch dams is pro

ISSN:0098-8847    

DOI:10.1002/eqe.4290130605

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThis paper presents some results on the following subjects obtained fromin‐situforced vibration tests and earthquake observations. (1) The characteristics of the radiation damping of soil‐foundation interaction systems vs. non‐dimensional frequency a0(=ωr/Vs) were experimentally estimated by the equivalent damping ratios hH( =K′H/2KH) andhR( =K′R/2KR), which were defined by complex stiffnesses 1KH(=KH+iKH) and 1KR(=KR+iK′R) of soil. The results forhHandhRof base rock were compared with those of soft soil. (2) A comparative study of experimental and theoretical results was made. The theoretical results were obtained from elastic half‐space theory. (3) A semi‐empirical equation to estimate the equivalent S‐wave velocity for the elastic half‐space model is proposed here, considering the effects of layered media. (4) Various comparisons of the results of 1KH, 1KR,hHandhRof forced vibration tests and earthquake ob

ISSN:0098-8847    

DOI:10.1002/eqe.4290130606

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractIt was pointed out in our previous paper that there exists a vast amount of fuzzy information in both objective and constraint functions of optimum design of structures. Then the idea of fuzzy optimum design of structures was first proposed and the problem with fuzzy allowable intervals of the physical variables (structural responses and sizes) could be solved via the α‐level cut approach.In this paper, the procedure of fuzzy optimum design of aseismic structures is further developed. For this purpose, the concepts and definitions of fuzzy predictive earthquake intensity, fuzzy response spectrum and fuzzy structural response are given. A solution of the programming problems with generalized fuzzy constraints (including both fuzzy constraint functions and their fuzzy allowable intervals) is put forward; one of its special cases is the χ‐level cut solution in Reference 1. The satisfaction degree of a fuzzy constraint function to its fuzzy allowable interval is defined, by which the problem considered is transformed into a series of non‐fuzzy programmings. Then, a series of optimum points can be obtained which make up the solution of the fuzzy programming.As the solution of fuzzy programming contains not one but a series of optimum points, a two‐step approach is presented to the fuzzy optimum design of aseismic structures. The first step is to find out the set of minimum cost design points corresponding to different design levels. In the second step, both construction cost and earthquake‐caused loss expectation in the service life of the structure are traded off to find the optimum design level as well as a corresponding optimum de

ISSN:0098-8847    

DOI:10.1002/eqe.4290130607

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290130608

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290130609

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290130601

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY