Applied Mechanics and Materials Vols. 71-78

Abstract: The natural environmental erosion and human factors such as the impact of traffic accidents, crack propagation, concrete carbonation and etc, make the bridge’s damage more serious. Therefore, the bridge damage diagnosis has become a hot field of bridge engineering issues. This paper put forward the fractional diagnosis method of multi-span bridge structure reflecting the structural cracks and carbonation damage. In this paper, adopting the optimization equivalent method, the finite element model of damaged structure is set up according to the damaging characteristic of multi-span continuous bridge structure. A damage index of strain mode with practical meanings is adopted which can reflect local damage. Basing on this index, fractional-step detection method of structural damage is presented. The first step is to identify the damage region, then locate the detailed damage location and degree; Performance of the proposed damage detection approach is demonstrated with analysis of a multi-span continuous bridge. The result turns up trumps.

Abstract: Wuhan city circle or Wuhan"1+8" city cluster area is one of the most important development strategies of city group in the central China. Wuhan"1+8" city cluster area has brought unprecedented opportunities and challenges to sustainable development by a comprehensive reform in a special resource-saving and environment-friendly society policy. The ddevelopment of Wuhan"1+8" city cluster area not only benefit the development of Hubei Province, but will also have a positive impact on the surrounding provinces such as Hunan, Henan, Jiangxi, and Shanxi. This paper discusses the opportunities and challenges of sustainable development in Wuhan"1+8" city cluster area from several perspectives and provides some suggestions and policies for the sustainable development in Wuhan"1+8" city cluster area

Abstract: Mine surveying is an important part and infrastructure protection of mine production and mine construction, and it is also very important basic work of coal mine safety production. This article summarized the development process of China's mine surveying for 60 years, the development process of China's mine surveying was from Transit Times which angling and distancing separately to Electronic Total Time which angling and distancing combo. Today, China's mine surveying has developed into an information science which combines with measurement and optoelectronic technology, computer technology, global positioning system (GPS), geographical information system (GIS) , remote sensing (RS) , D-InSAR and Unmanned Aerial Vehicle Remote Sensing with the rapid development of science and technology. This paper also analyzed the development status, opportunities and challenges-digital of China's mine surveying , and pointed out its development direction and what measures should be taken.

Abstract: Xiaolangdi Reservoir undertakes 90% of the Yellow River runoff and 100% of sediment discharge. To ensure the long-term utilization of Xiaolangdi reservoir is the key to prevent the flood in the lower reaches of the Yellow River. Take Luokou Hydrologic Station located in the lower reaches of the Yellow River as an example, conduct an analysis from the aspects of sediment retaining of Xiaolangdi Reservoir, scouring and deposition condition of river channel in the lower reaches of the Yellow River, water level performance for years of different flow of ten times’ water-sediment regulation, predict on the sand blocking operation period of Xiaolangdi Reservoir, water level of specific flow of river channel in the lower reaches of the Yellow River and scouring and deposition condition of river channel, which has played a reference role for the flood control in the lower reaches of the Yellow River.

Abstract: Small farmland irrigation and water conservancy facilities form an important part of the county-level agricultural infrastructure and one of the key factors that affect agricultural production. The paper takes the Jiyang County in Shandong Province as a case to explain ways to address water shortage and underdeveloped small farmland irrigation and water conservancy utilizing dedicated investment to construct small water-saving farmland irrigation and water conservancy projects. In the 2011 project, 9 pumping stations will be built and 9 low-pressure pipeline irrigation systems will be deployed, with a total of 6,204m³/h designed pumping capacity and 450KW installed capacity that cover an irrigation area of 18,200mu. After completion of the project, the whole county’s effective irrigation area, water-saving irrigation area, efficient water-saving irrigation area, irrigation water efficiency and the overall grain production capacity will be increased significantly with improved benefits from increased yield, saved land, reduced labor and improved water efficiency. The national economic evaluation shows that the project is feasible. The construction of small water-saving farmland irrigation and water conservancy projects is, to certain extent, typical and universal, and can be referred to by the counties, municipalities and district elsewhere across the country in their respective efforts in small farmland irrigation and water conservancy constructions. Therefore, the project is worth recommending.

Abstract: Application of finite element software ANSYS coupled with the train-ground dynamic model is developed to predict the torsion effect of asymmetric structure. Respectively analyze on eccentricity ratio is 0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1.0. Results show that the ground vibrations by the train are slight. Eccentricity of the structure has certain effect on horizontal displacement, horizontal angle displacement, and floor horizontal acceleration.

Abstract: Thermal stress is a factor of the large bridge structure cracks which can not be ignored. As a continuous rigid frame bridge in a certain period of Guangzhou ring express way the background, using the general finite element program MIDAS/Civil, only considering the load of temperature effect established the original bridge model, reference the China road and bridge design for temperature effect on the bridge numerical analysis. By section temperature difference and system temperature change getting the stress distribution and the stress distribution of section temperature difference and the system of heating section, cooling section and the system temperature gradient linear combinations ,the stress we got will get a large section of the stress to the actual distribution of bridge crack detection have a good agreement . Cooling load combination get the Maximum tensile stress at the bridge span beam bottom and the result exceeds the tensile strength of concrete, it gets most impact to the end of the beam cracks. On the bridge design to consider the temperature effect the conclusion has some certain reference value.

Abstract: The first impoundment of the Three Gorges Dam reservoir in China started from a water surface elevation of 95 m on June 1, 2003 and reached 135m on June 15, 2003. After that, an intensive rainfall lasted nearly a month, Qianjiangping landslide occurred on the early morning of July 14, 2003 and caused great loss of lives and property. In order to study the influence of impoundment and rainfall, based on the coupling model of runoff and infiltration, the seepage and runoff of the landslide during impoundment and rainfall were simulated. The results show that the toe of slope are immersed because of the change of reservoir water level, the suctions of sliding mass and sliding zone on upper slope are decreased and the runoff occurs because of intensive rainfall. These are inducing factors of the landslide. The results are useful to study instability mechanism of the landslide.

Abstract: Based on elastic theory, the four basic assumptions and the failure model of concrete beams strengthened with CFRP, deduced the formulae about the concrete beams strengthened with CFRP with concentrated load. Results show the biggest interface shear stress is at the at the anchor end, it not only relate to the material property of CFRP and concrete, but also to the thickness, width and bending moment at the anchor end etc.. Reducing CFRP stiffness and thickness or increasing viscose layer thickness, these can reduce the maximum interface shear stress at the end of anchoring.

Abstract: The three-dimensional propagation directions of earthquake ground motion near ground surface are estimated for eight earthquakes. By the NIOM method, three dimension (3-D) oriental angles are resulted in determining the arrival time of an incident wave and a reflectiveed wave. In this study, the estimation method of 3-D propagation directions is developed rationally and confirmed reliably with the independent data of Chiba array in Japan. The propagation directions are equivalent numerically to the geographical position of plural spots in horizontal and vertical, and the theoretical result obtained by the structural model of global horizontal layer velocity.