Applied Mechanics and Materials Vols. 744-746

Abstract: In recent years, numerical simulation of strong ground motion has been well developed with the progress of earthquake science, and it has become an important approach to estimate strong ground motion. In this research, we improve the original program of EXSIM and the modified program named MEXSIM to calculate the Peak Ground Acceleration (PGA) and Peak Ground Velocity (PGV) which is essential for seismic hazard assessment of Hengshui area. Considering the impact of V₃₀ (the average shear-velocity down to 30 m) we calculate the impact of two scenario earthquakes from the rupture processes of Hengshui fault and Qianmotou fault. Comparing to Qianmotou scenario earthquake, if the instability fault is Hengshui fault, the PGA and PGV could be 200-360gal and 20-35cm/s respectively in Hengshui city.

Abstract: In recent research of seismic engineering, the damage of bridge due to vertical motion aroused wide concern. Field evidence, experimental results and numerical simulation analysis suggested that vertical ground motion can significantly impact the seismic performance of reinforced concrete (RC) bridge. In this paper, firstly, a FEM model of a continuous rigid frame bridge in China was established . Then the bridge was analyzed using time-history analysis under strong earthquake . Internal force excluding and including vertical motion are compared.Then, the incremental dynamic analysis (IDA) and fiber model are used to calculated the vertical displacement of the node in the top of pier and the sectional curvature of pier. Computational results show that vertical ground motion can increase the internal force and displacement ,as well as reduce the ductility and moment capacity of piers. It is concluded that vertical motion can't be ignored in structure design.

Abstract: An improved new damper was presented. The mechanical properties of the damper were conducted by the numerical simulation method under the cyclic loading. Also, the seismic mitigation effectiveness of the damper was verified though Time History Analysis. The results show that the improved damper has good hysteretic behavior. It can significantly reduce structural displacement response. Furthermore, the seismic performance of Masonry Buildings with Frame at the Bottom was studied by equipped the improved damper. The control effect was compared with Masonry Buildings with Frame at the Bottom and Masonry Buildings with Two-story Frame at the Bottom.

Abstract: This paper establishes three models using ANSYS, which were timber structure of Guangyue Tower, timber structure-tower base and timber structure-tower base-foundation. The first 3 natural frequencies of timber structure respectively were 0.8524Hz、1.1273 Hz and 1.7426 Hz through modal analysis, which were compared with calculations from code. Lanzhou Wave was chosen to analyze the seismic response of Guangyue Tower, and the amplitudes were adjusted to 55gal and 310gal respectively according to the frequent earthquake and rare earthquake, which were inputted to the above models. As can be seen from the calculations, the maximum displacements of the three models were in the top nodes, and tower base had a greater impact on vibration of timber structure, which could not be ignored in seismic response analysis; considering soil-structure interaction in seismic response analysis could better reflect the actual situation of Guangyue Tower.

Abstract: Golog Tibetan Autonomous Prefecture is located in the hinterland of the Qinghai-Tibet Plateau, located in the southeast of Qinghai Province. And the unique geographical, climatic and economic conditions created a unique local houses - Tibetan Diaolou. Tibetan houses in Golog most used local materials and were made of stone, wood, soil, grass, rattan and other natural materials. The Tibetan Diaolou are assembled by flagstone to form a load-bearing structure of stone walls and wooden. The towers mainly distribute in Yaertang Xiang and Dengta Township which are located in the coastal of Make River. Through field investigation of two rural villages, this article has a deep understanding of the structure performance of Tibetan Diaolou. This paper analyzes its structural problems of safety and seismic performance, trying to improve the seismic performance of Tibetan Diaolou.

Abstract: Taking Liaocheng Guangyue tower as an example, based on the on-site measurements, to determine its dynamic characteristics and provide a basis by numerical analysis method for determining traffic incentive effect on the ancient timber buildings. From the research, we can conclude that the first-order self-vibration frequency of Guangyue tower can be taken as 1.638Hz, the corresponding natural vibration period is 0.61s,the damping ratio is 1.098.

Abstract: The transverse seismic performance index system of urban mass transit underground structures was presented, which included both intensity index of component and overall deformation index, in order to reasonably evaluate its damage degree under seismic excitations. Intensity index of component had two grades and limit values of two levels ware provided. Overall deformation index included story drift angle for rectangular underground structures and diameter deformation rate for shield tunnels. Performance index values of urban mass transit rectangular underground structure story drift angle ware put forward by reference to modified performance index values of ground structure story drift angle, which was based on a statistical analysis for experiment data of forty-six groups concrete-filled steel tubular frames and one hundred forty-five groups steel-reinforced concrete frames and took into account similarities and differences between surface structures and underground structures. Based on relation between tunnel diameter deformation and stress state of tunnel concrete and bolts, the diameter deformation rate was derived from the analytical solution using compatibility of deformation for a segment cross section. And the diameter deformation rate was also computed by means of incremental dynamic analysis method for different sites under various earthquakes. It is found in the study that based on two performance levels, limiting value of diameter deformation rate is obtained.

Abstract: The penetration cracks in sluice concrete structure have more disadvantage influence on the structure integrity. On the condition of earthquake, it may cause structure collapse. For a typical sluice structure found penetration crack in construction, the finite element model is created and the structure dynamic computation is applied with response spectrum method. The calculation results show if the reinforced steel bar cross the crack is not rusted and destroyed, the tension stress in the sluice and the general safety factor against sliding will meet the corresponding standard. As for the existing cracks, seepage prevention is suggested to avoid steel bar against rust.

Abstract: Cases of tunneling adjacent to existing structures are common nowadays in urban construction. The interaction between newly constructed tunnels and existing underground structures is an important issue, while the previous works mainly focused on the effect that constructing a new tunnel would have on existing structures. In this article, the effect that existing structures would have on newly constructed tunnels was come up with, and a model was proposed to analyze the confinement of existing structures to the tunnel surrounding rock. Discussions were carried out theoretically and numerically.

Abstract: Settlement of comprehensive pipe is inevitable disturbed by construction and surrounding environment, in order to better understand the settlement rule of comprehensive pipe. Based on a large amount of monitoring data collected from integrated trench, a simulation model is proposed to analyzed comprehensive pipe settlement by using ABAQUS, the case results show that the simulation model performance can analysis the synthesis trench settlement. It has high prediction accuracy and fit for the settlement of integral comprehensive pipe.