Applied Mechanics and Materials Vols. 166-169

Abstract: Using ANSYS for the three add-layers beam-column joints to non-linear analysis their seismic performance.The results showed that: Model’s hysteresis curve all showed a square spindle-shaped, smooth and full curve, but find the "pinched rope" phenomenon, and have strong energy dissipating capacity;The joint reinforced by Haunched plate has strong bearing capacity, stiffness and energy dissipating capacity, meanwhile, this type of joint contains highest yield strength, largest hysteresis loop area and ductility factor, and has good ductility and energy dissipating capacity. So, it can be used in the earthquake area;The local damage of these joints are start at one point, and out gradually spread. The first joint’s beam-column connection point destruction firstly, and the joint lose its bearing capacity because the components off each other. The third type of joint formed plastic hinges during the process of loading, plastic hinges can change the failure mode of the joint.

Abstract: An experimental study of the damage behavior of two kinds of concrete with different strength grades has been performed using 100mm cubes subjected to increasing hydrostatic loading history, namely, the isotropic compression at high pressure. The compressive strength and ultrasonic velocity are measured before and after loading history, respectively. The damage degree of these cubes is defined as the reduction of compressive strength based on the continuum damage mechanics theory. Linear and exponential curve fit of experimental data is performed respectively to describe the evolution of damage as well as the descent of ultrasonic velocity with respect to the loading history. It can be seen that, the influence of hydrostatic loading history upon strength and ultrasonic velocity could really reflect that upon the degree of damage development. In general, ultrasonic inspection is convenient and applicable to estimation of damage of concrete due to loading history in engineering practice.

Abstract: The load-transferring mechanism under the action of vertical load and the role of bearing load by bearing disks in loess area were analyzed based on results of field static loading test of the squeezed branch piles. The results indicate that load transfer law of squeezed branch pile is transferred from top to bottom, and load of bearing disks is about 60 percent of the top load of the pile, stress superposition efficiency existed between bearing disks, and the minimum critical spacing of disks is 2D (D is the diameter of the bearing disk), the estimated bearing capacity of the squeezed branch pile is higher than the measured value.

Abstract: By the axial compression tests on a total of 19 high strength concrete columns wrapped with CFRP cloth, the influence of shape section and different layers on the axial compressive strength and ductility is studied. The experimental results indicated: high strength concrete columns wrapped with CFRP in increasing the bearing capacity and ductility of concrete columns is still valid, its effect on the improvement of ductility is much greater than its capacity.

Abstract: In order to evaluate the impact of mud cake thickness on shearing strength at cement-formation interface accurately, a feasible simulation experiment system and evaluation method was established, which includes preparation of artificial core, formation of mud cake, maintenance of the samples and testing of the Shear bond strength of cement-formation interface. Based on this, by taking commonly used drilling fluid from Shuangjiang oilfield, Jinglou oilfield and Zhongyuan oilfield in China as examples, the laboratory impact evaluation results show that: (1) As for different drilling fluid system, the shearing strength at cement-formation interface of the cement-formation interface keeps a general tendency to an obvious decline as the growing of the mud cake thickness. (2) In the same drilling fluid system, though different in the time of maintenance, the variation trends that the shearing strength at cement-formation interface declines as the growing thickness of the mud cake are similar. (3) The declining rate of shearing strength at the cement-formation interface will reach 83.4 %-99.9 % when the mud cake thickness is 5mm. These developments of this paper can be used to optimize the design of drilling fluid and cementing technology, and consequently improve the cementation quality of cement-formation interface to meet the demands of highly-efficient petroleum production.

Abstract: To study the effect of various types of defects on the bearing capacity of reticulated shell structures, this paper analyzes the structural nonlinear mechanics performance under physical defects and geometric defects, combining with the matrix displacement method of structure, obtains the impact law of two defects on the reticulated shell structural bearing capacity. Two reduction methods of corresponding defects are put forward which can be used as reference in engineering design and construction. Afterwards, it is pointed out and demonstrated that the safety factor should be defined by a lot corresponding experiments.

Abstract: Vertical ultimate bearing capacity of static pressure pipe pile is influenced by comprehensive factors, such as pile body, soil around pile and construction conditions., and the relationship between the impact factors and ultimate bearing capacity of a single pile is highly complexity and non-linear. This paper is based on collecting the data from static load tests in typical geological conditions of Liao-shen area, construction records, and test pile sites. And then combine analysis of principal component with SVM to analysis the prediction of the single pile’s vertical ultimate bearing capacity. This model can reduce the number of SVM input variable dimension to improve speed of training support vector effectively. At the same time it can eliminate the influence factors of multiple correlation. The results show that the proposed principal component analysis SVM model has good predictive accuracy and generalization ability, and opens up new avenue of research for analysis of static pressure pipe pile vertical bearing properties.

Abstract: Most of landslides occurred because of the action of water. Dynamics of groundwater is directly related to the stability of landslide. Change of groundwater level is one of the most important factors of landslide prediction. In this paper, We used waterclocks to monitor groundwater level of K144 landslide for two years and found that different slope regions of the groundwater level showed different variation. Groundwater level of unstable region changes between 4m ~ 6m in the sandy mudstone area where average precipitations is about 1000 mm, which were the same trend with the monthly total rainfall changing; groundwater level of stable area changes around 1.5m, which was unobvious in response to the monthly accumulative rainfall; the rise of groundwater level is the important reasons for the K144 landslide sliding.

Abstract: Based on brief introduction to the concept of vibration control, this paper discusses many different types of device for vibration control under wind load in high-rise buildings. By contrasting and analyzing the performance of each type of device, the classification and characteristics of the vibration control device for wind load are summarized, which could be used in choosing the proper device in controlling vibration under certain conditions.

Abstract: In this paper, the dynamic response and failure modes on the T-shaped concrete-filled steel tube core columns under blast loads were simulated with the finite element analysis software ABAQUS. According to analysis the lateral displacement of the midpoint of the column and the stress of the concrete, we can obtain the failure of the column. At the same time, we simulated the effects on the column when it was under different blast loads.