Advanced Materials Research Vols. 250-253

Abstract: Based on the analysis of the uplift mechanism theory of the disk piles, a model test device was designed to study the uplift bearing capacity and deformation behavior of the disk piles and to compare with the equivalent diameter piles. Uplift loading tests were carried out on the equivalent diameter pile, the single-disk pile and the double- disk pile respectively. Through the test, it was proved that the uplift bearing capacity of the disk piles was much better than the equivalent diameter pile. The bearing capacity of the single-disk piles was better than the double-disk piles in the test. This was mainly related to the embedded depth of the upper disk was not enough and the specific failure mode. So, a reasonable design was necessary.

Abstract: The related components of material testing machine (e.g., pressure plate, pressure head, compression bar, etc.) produce distortion in the experiment. It is obviously irrational to use the stroke to replace the specimen displacement, which can’t be measured directly by the extensometer in the destructive test. Therefore, the evolution of specimen displacement, machine displacement and stroke of 45 steel, duralumin alloy and sandstone was analyzed under uniaxial monotonic loading and uniaxial cyclic loading. The results show that the deformation of the related components of universal testing machine, which increases/decreases along with the increase/ decrease of load, can’t be ignored. And there is a good one-to-one correspondence between the machine displacement and the load. It also has nothing to do with the types of specimen materials and the experiments. The relationship of machine displacement and the load can be used to determine the specimen displacement indirectly.

Abstract: Two groups of model pile tests was designed to study the influence of horizontal load on compressive bearing capacity of different types of pile. Experiment showed that the existence of horizontal load at the pile top had large influence on the bearing capacity of equal-diameter piles and single-disk piles with the disk being set at the upper of pile, but little influence on double-disk piles with the disk also being set at the upper of pile. It illustrated that the disk being set at the upper of multi-disk pile has better effect on the resistance to horizontal load.

Abstract: Based on the technological features of highway tunnel information design and construction，the relationships between stress-deformation and space-time were studied profoundly, combining closely to the monitoring practice of Heijiagou highway tunnel in Beijing to Chengde express way. With the results in rock mass stress monitoring, the adjustment law of stress was analyzed; and the relationships among stress and rock mass classification, burial depth and geologic conditions were disclosed. A profound study about the features of the relationship between rock mass deformation and space-time was carried out, as well. Finally, the application of monitoring results on rock mass classification, hazard forecasting and determination of the best time to construct the secondary supporting was introduced.

Abstract: Typical earthquake damages of Reinforced concrete columns in the Wenchuan earthquake are introduced, and the damage characteristics of concrete columns are described, then several typical destructive modes of Reinforced concrete columns are summarized. Further, various reasons of destructive modes are analyzed. Final, some practical advices are proposed to reduce the damages of reinforced concrete columns.

Abstract: Through the method of dimensional analysis, the dimension equations of loess ground deformation of dynamic compaction are established. Based on the data obtained from practices of dynamic compaction and the methods of statistics , empirical equations of both the crater depth and the average enforced settlement relating the soil parameters and construction parameters are presented. Finally, the equations are verified by several project examples, and the results show that the calculated results agree well with experimental results. These equations provide a practical way for the prediction of surficial deformation of loess ground during dynamic compaction.

Abstract: An experimental study on the torsional behavior of two 1/6 scale core walls: one reinforced concrete core wall with concealed steel trusses and steel tube-reinforced concrete columns, and one normal reinforced concrete core wall, was carried out under eccentric horizontal cyclic loading. The torsional load-bearing capacity, torsional angle ductility, torsional hysteresis characteristics, torsional stiffness and its deterioration process, torsional energy dissipation and damage characteristics of the two specimens are herein discussed. Results show that the torsional performance of RC core walls can be improved by embedding the concealed steel trusses in the walls and setting the steel tube-reinforced concrete columns as boundary-columns.

Abstract: Gravity abutment widely uses for substructure part of the bridge structure. For many reasons, there are many damages take place in the parts of abutment. The objective of this study is to evaluate the strengthening effects on the performance of highly structure of Gravity abutment. The results of damage inspection show that these damages are very serious in the direction of height and width of the abutment structure. Therefore, there is need to strengthen the abutment structure to improve the carrying capacity. There are two experimental models. The first model uses one ring of carbon fiber sheet and the second uses two rings of carbon fiber sheet .The results of experimental show that there are good effects when using carbon fiber sheet strengthening method.

Abstract: H-type vertical axis wind turbine is a new type wind turbine. Currently the research on its support tower is still in the blank stage. Based on the work principle of H-type vertical axis wind turbine, the factors about the structure selection of the support tower were analyzed, and parametric analysis of structure selection was carried out for a pilot project. Finally some useful conclusions were obtained to guide the design.

Abstract: According to the behavior of seismically isolated continuous bridges, the bidirectional nonlinear characteristics of lead rubber bearing are taken into account by using two orthogonal nonlinear level spring elements. Based on the FEA software, the analysis models of seismically isolated and non-isolated continuous bridges are established. And the nonlinear seismic response for these analysis models is carried out under the function of the reasonably chosen seismic motion.