Advanced Materials Research Vols. 378-379

Abstract: With the rising of urban rail transit planning and constructing in China, the relationship between rail transit and bus must be located. After analyzed the inevitability of competition and the necessity of cooperation between rail transit and bus, this paper strategically located the relationship between rail transit and bus. At last, based on the characteristic of competition between rail transit and bus, this paper brought forward specific measures of staggering competition with cooperation corresponding to different rail transit develop stage to implement rail transit and bus. Higher level competition will be formed, and the competition result is not “single win” but “both win”.

Abstract: Frame structure on a slope is a common kind of structure in a mountainous area. It can diminish the impact on environment, by avoiding to dug or fill the slope, using an opening platform, supported by beams and columns. Because the frame structure on a slope connects with the ground on different elevation level, it is evidently different from general frame structure in seismic design. Four sets of frame structure example on a slope sample are designed, with three opening floors connected with the ground on different elevation level, and three, six, nine, twelve upper floors correspondingly. The seismic responses characteristics of frames on a slope are studied in the paper from period, lateral deformation, seismic shear and so on, based on the analysis of the characteristics of frame structure on a slope. The main conclusions are as follows: the slope can enhance structural lateral stiffness to a certain extent; the opening floors connected with the ground on different elevation level, are not necessarily frail stories; the distribution of seismic force is uneven between the columns in the same floors which connect with the ground on different elevation level, and fixed columns undertake more than others, making them more fragile; the torsional effect is noticeable in the frame structure on a slope.

Abstract: In the consolidation theory of sand drain foundation settlement, the influence of groundwater level changes on the soil consolidation has been paid less attention. Therefore, discussing those changes' influence will help to deepen and perfect the sand drain consolidation theory. Through theoretical research and field measurements, the concrete influences of water level weight, dissipation rate and other factors on the consolidation process are obtained. This helps to improve the consolidation theory and efficiency.

Abstract: Anti-seepage reinforcement technology of splitting grouting to improve the stability of dam, has been an effective reinforcement method in the field of dam reinforcement. Based on the extended SMP criterion and stress-dilatancy relation considering large strain, the governing equations of axisymmetric problem in the plane strain condition and the partial differential equations for the boundary-value problem of cavity expansion in frictional cohesive soils were established. Then, the early phase of splitting grouting is regarded as the plane strain question of cylindrical expansion infinite soil. Under initial grouting pressure, the soil body was supposed as ideal elastic mass. However, the soil body was supposed to generate plastic damage considering large strain with the increase of grouting pressure and submit the extended spatial mobilization plane theory. Solutions of radial and hoop stresses and strains around the grouting cavity were obtained by recursive computations. Furthermore, the influence of damage softening parameter, cohesion and friction angle was examined by a parametric study.

Abstract: Seismic response of a high-rise building under rare earthquake is numerically investigated in the paper. The Height of the building is 266m, which goes beyond the limit of 150m in Chinese standard, so nonlinear analysis should be performed to investigate its elasto-plastic behaviors under severe earthquake excitations. In the finite-element model for analysis, beam-column members of the structure are simulated by beam elements, while the core tube is simulated by shell elements. The concrete damage plasticity model is used for concrete members, while the kinematic hardening rule is defined for steel beam-column members. Four sets of earthquake wave, including 3 sets of strong earthquake records and 1 set of artificial wave, are adopted in the analysis. The analysis results show that, under severe earthquakes, steel frame members and steel truss members in the strengthened floors keep elastic. Severe damages are detected in almost all coupling beams in the core tube, as well as shear-walls near strengthened stories, where lateral stiffness would decrease seriously. Through the investigation, it is also found that the largest story drift is less than the maximum allowable value in the Chinese code for seismic design of buildings. So it is concluded that the high-rise building will not collapse when the place is subjected to severe earthquakes. Besides, some design suggestions are proposed according to nonlinear dynamic analysis in the paper.

Abstract: To ensure the pressure bars to work safely and reliably, the most important thing is that the bars should possess sufficient stability. The previous massive domestic and foreign literature is just about the instability of the pressure bars under the function of longitudinal critical force, the research on the instability under action of the lateral critical force is seldom. So the research on the stability under the function of the lateral critical force is of great importance. This paper deduces the formula of the lateral critical force with the energy method for the first time when the pressure bars is in the condition of instability, and the formula has good reference value for the research on instability of the pressure bars under the lateral critical force.

Abstract: The mechanical analysis is applied for the steel box girder bridge with orthotropic plate and pavement by means of Finite Element Method. The interaction between steel bridge and pavement on the long-span steel bridge is evaluated in three calculation stages. The emphasis of the analysis includes the mechanical characteristics and the influential factors of large components(cross diaphragm)and local components (U-shaped ribs). Considering the mechanical changes by the load of heavy-duty vehicles and heavy load with braking, the interfacial shear failure is studied for the main form of damage. In view of this major form of damage, this paper puts forward the corresponding mechanical analysis of the indicators.

Abstract: Regarding the design response spectrum in the code for seismic design of buildings as target spectra，the 28 acceleration histories are formed artificially．They are used as the inputs ground motion in earthquake response analysis．Four site classifications profiles were selected or constructed from practical site profiles．With the use of 1-D equivalent linearization wave motion method that is wildly used at present in site seismic response analysis, the platform values of surface response spectrum for different profiles under different ground motion inputs were calculated．Different platform values of the response spectrum and relational expression which is seven input earthquake motion intensity and site classifications have been given by statistical analysis.

Abstract: The static and dynamic behavior of an upper deck type steel arch bridge was demonstrated. During the static analysis, both material and geometric nonlinear was considered based on finite element (FE) method. In-plane fault displacement case and out-off-plane fault displacement case were compared. During dynamic analysis, the model was modified and simplified firstly, and then the natural modals and the characteristics of the mode shape were analyzed. Both the in-plane seismic input case and out-off-plane seismic input case were analyzed. The different yielding process of members including main ribs, chord and columns were represented, and the possible damaged parts of the bridge were analyzed either.

Abstract: In order to study the characteristic of seismic response of the reinforced slope subjected to earthquake, the seismic response spectrum of slope reinforced with piles under the two different diameters were compared and analyzed. The seismic acceleration response shows a steady amplification with the increase of height without water in substratum, and the maximal seismic response occurs near the crest of slope. The dominant frequency of the amplification of seismic response spectrum of the slope reinforced with piles under the smaller diameter obviously shifts to the medium and low frequency. In addition, because of the liquefaction of substratum and the resulting dynamic failure of the pile, the response components of the medium and low frequency also are strengthened further. The results show that the global stiffness of the reinforced slope is obviously affected by the diameter of the pile and the liquefaction in substratum, which thereby affects the seismic acceleration response and the distribution of spectral amplification factor.