Applied Mechanics and Materials Vols. 90-93

Abstract: Perimeter protection is an important physical protection approach for buildings and infrastructures, which is also regarded as the first line of protection. Vehicle borne improvised explosive devices (VBIED) have been recognized as a major design threat by many government agencies for years, since they have been so extensively used in past terrorist attacks against critical buildings and infrastructures. Preventing unauthorized vehicles from approaching a protected area with vehicle barriers installed in perimeter of the buildings and infrastructures would consequently reduce blast and debris threats. The history of test certification standard for vehicle barriers is briefly reviewed. The research achievements on anti-ram bollards, one type of vehicle barriers, in the fields of crash test, numerical simulation, and design theory are presented. The remaining problems and deficiencies of the research are pointed out and the corresponding proposals are put forward. Finally, some further research works on anti-ram bollards are proposed.

Abstract: This article mainly studied the seismic response of high-rise RC frame and the damping effect with viscoelastic damper. Taking a reinforced concrete frame structure of 12 layers as the research object, six schemes of damper installed were designed and the dynamic characteristics of these schemes were analyzed. The time history response analysis of 3D Tianjin waves was studied for the six schemes under frequent earthquake. The results show that seismic capacity of the structure could be significantly enhanced with dampers under frequent earthquake. Meanwhile, different damper installations also can make the structures have different damping effect.

Abstract: In order to improve the wind resistance of single-storey house in the rural areas, this paper has carried countryside house's rigid model on the wind tunnel test in view of the south area. This paper has studied coefficient distributed rules of the single-layer house building and calculates the shape coefficient under various wind angles, and draws the build coefficient distribution figure finally. The result indicated that when the wind angles are 0 or 90 degrees, the front wall is most unsafe. When the wind angles are 60, 90, 150, 180 degrees the back wall is unsafe. When the wind angles are 0, 180 degrees wind angles, the flank wall are unsafe. But speaking of the entire house, 0 degrees wind angles is the unsafe wind angles.

Abstract: In this paper, a program is developed based on Matlab, in which subsidence value of any shape face of a single point, and multi-points were calculated, generated five mobile deformation curve was displayed, two-dimensional subsidence and three-dimensional visualization to display and data query functions were realized and verified through 2 examples. The results of the program can be intuitionistic and scientific basis for future damage caused by underground mining.

Abstract: In this paper, an algorithm based on the network method suggested by Oppenheim for calculating the radiative heat flow in a cavity of structural members, say hollow core concrete slabs, exposed to fires is presented. It is assumed that the pressure in a cavity keeps atmospheric pressure through the whole cause of a fire, and the lost heat from the air due to expansion and immediate moving away from a cavity is neglected. The heat in a cavity is transfer via both heat conduction in air and thermal radiation among boundaries, and special regard is paid to modeling heat transfer by radiation. The effective radiative heat flow system of equations is derived and expressed in matrix form. The system of equations features a symmetric coefficient matrix, which can be stored in a one dimensional array, and can be solved using LDL^T factorization. Node radiative thermal loads are calculated from effective radiative heat flows at edges of elements located on internal cavities. The nonlinear finite element program TFIELD written by first author has employed the new algorithm. Temperature distribution in two structural members with cavities are calculated using TFIELD, and numerical results demonstrate that the new algorithm is very effective and is useful for further study of structural behavior of structural members under fire conditions.

Abstract: The structural vulnerability analysis decides the probability of the structural failure under the earthquake loads. According to the seismic failure and the failure mechanism of the structure, this paper defines the structural resistance with the limit states of the structural function and builds the probability relation between the structural failure and the structural resistance with which the failure probability of a structure under the load of some intensity earthquake can be decided and the curves of structure vulnerability can be drawn. With this method the structural tolerance of earthquake loads can be evaluated and the safe reliability of the structure can be predicted.

Abstract: Detailed calculation of the dynamic displacement and dynamic internal force response of each structual member of wharf structure in the earthquake are conducted to structural response analysis of finite element numerical model in the Cuntan container wharf under multi-support excitations(MSE). The comparative analysis of results of calculation evaluates the characteristics of the whole dynamic force of the structure , validates and optimizes engineering design and accumulates design experience, simultaneously,in order to further master performance states of container wharf and the application of an advanced type wharf to other regions.

Abstract: With interchanging vegetational reconstruction of Ying Rui highway as the research object, using Drying method as principal combining with TDR method,carry out communication areas of different vegetation types and different matrix types of slope area of dynamic monitoring soil moisture in the spring, the results show:Soil moisture content in spring declined as time goes on from March 8, to April 7 day. Dynamic general trend of soil moisture declined from 6：00 am to 6 :00pm,the soil moisture content overall drop which slightly fluctuates after afternoon, but has no obvious peak, and increases again after evening .The soil moisture content of two kinds of reconstruction models varies with different soil layer thickness:0-20 cm soil shows trees reconstructing model >shrubs reconstruction model ;20 to 40 cm soil shows bush rebuild model> trees reconstruction model.

Abstract: The impact of tunnel construction upon the environment is analyzed from the perspective of ecology, air, sound and society respectively. In the case of Three Ponds Tunnel, risk assessment is made on the environmental impact in different stages of tunnel construction. Environmental protection measures are put forward, which can serve as reference for environmental protection in the construction of similar geotecnical engineering projects.

Abstract: A cost combined life cycle assessment was carried out to estimate the economic and environmental impact of redmud as aggregate in cement production. Results showed that the raw materials, transport, electricity and coal had the highest contribution to overall cost, while coal production and direct emissions represented the dominant contribution to overall environment impact. Improving energy and raw material efficiency and minimizing raw materials transport distance are the efficient way to minimize overall environmental and economic impacts.