Applied Mechanics and Materials Vol. 777

Abstract: The mechanical properties of high-strength concrete was studied in the laboratory, and obtained a high strength concrete uniaxial compressive strength changes with curing period, found that low temperature curing C100 Poisson's ratio of concrete is 0.24, and elastic modulus reached about 52.5GPa. The test results are applied to the numerical calculation, established a separate type reinforced concrete wall, and the multiaxial loading the stress state is simulated, the research shows that it is applied to C100 reinforced concrete shaft lining under its own gravity and the surrounding soil earth pressure, the maximum effective stress are respectively 25MPa , and effective strain is 4E-4mm, structure of shaft wall failure caused by shear wall structure. Under the three state of compression, the strength of concrete is improved.

Abstract: In order to solve the problem of bending stiffness parameters identification of practical stay-cable, and provide bending stiffness correction for tension measurement. A method to identify cable bending stiffness parameters is proposed, and its basis theory established in paper. The method was applied to Xiazhang Sea-Crossing Bridge, the results showed that: Identification bending stiffness ratio is between 0.33 to 0.54 for relatively short cables of South Branch Bridge, and it tends to decrease with increase of cable length and force. However, the identification bending stiffness is close or equal to 0 EI_max for relatively long cable of North Branch Bridge. It testified that the effect of bending stiffness for long cable tension is small in engineering.

Abstract: The historic Hagia Sophia in Istanbul, which held the record as the world's largest domed building for about 800 years, is analyzed with a 3D finite element formulation, by using commercial FEA software ANSYS Workbench 14.5, to understand its structural behaviour under the action of static loading. Four different levels of structural systems are demonstrated and the their effects on the maximum values of the first principal stresses in the main dome are discussed.

Abstract: The damper parameter of a concrete-filled steel tube arch bridge is optimized. Random Fourier spectrum based on physical model is used to synthesis the random time-domain excitation. Four evaluation functions have been constructed as optimization of the objective functions based on energy dissipation and structural control indexes. Comparing two energy evaluation function combinations and traditional control evaluation functions, the damper optimization parameters have been obtained. Result shows that: Optimized damper parameters of concrete-filled steel tubular arch bridge under various seismic waves have high damping effect. After introducing the energy dissipation indexes, evaluation functions avoided the extreme value disadvantages of the traditional target, the final optimization results could be more economical and practical.

Abstract: In this article, according to the reliability appraisal of the structure of a heavy industrial plant which is near service limit years, we found several major safety hazard issues and proposed corrective measures to reinforce. On the basis of structural calculation and analysis, we could determine whether to upgrade the crane and propose the corresponding feasibility upgrade project, which can provide the basis for other similar identification.

Abstract: At present, both at home and abroad of tunnel surrounding rock classification methods and standards are all aimed at tunnel survey and design phase. It is the cause of that surrounding rock classification are very different between design phase and tunnel construction because of the limits of investigation techniques and geological data. It is the key to the real-time construction design problem that Sentenced to a stable state of surrounding rock based on the monitoring data. This paper determines the influence factors of tunnel convergence value clearance and obtained the tunnel convergence value clearance of principal component factor and power based on the statistical analysis of a lot of tunnel monitoring measurement data. It is put forward correction formula of dynamic classification of surrounding rock according to the theory of probability and statistics. The results show that based on the real-time monitoring of tunnel surrounding rock classification method is quite coincident with the actual situation of tunnel excavation in engineering applications.

Abstract: with the development of transportation infrastructure construction in the west, more and more excavation and support of all kinds of mountain tunnel been encountered in the project. Specific method of excavation and support should be ascertained according to tunnel types, size of section, depth of burial, wall rock types, hydrological condition, and construction machinery. Different excavation method will get different effect of wall rock stability .at present, there are variety of flaccid wall rock tunnel construction processes and methods, such as bench cutting method, ring cut method, CD method and CDR method, etc.

Abstract: For an arch rib of concrete filled steel tube (CFST) erected by cable-stayed cantilever method, the construction control becomes increasingly difficult along with the erection of rib segments, owing to more system transformation, and higher degrees of static indeterminacy. First, for the problems usually occurred in the process of ribs erection, this paper presented a line-shape control principle that is “erecting higher, remaining stationary”. Secondly, based on analysis of the merits and demerits of common methods for cable forces calculation, and according to the principle of “remaining stationary”, a new calculation method for cable forces was proposed. At last, based on an X-style CFST railway arch bridge with a span of 360m, this paper compared the cable forces calculated by the new method with the actual tensioned forces, analyzed the variation of segments displacement in the process of erection, and discussed the influence of prearranged height on weld width. The control principle and the calculation method for cable forces presented in this paper have been proved effective, by the line-shape data measured after the closure of arch ribs, which may provide valuable reference for the construction control of similar CFST arch bridges.

Abstract: The strain energy of dam body and its sensitivity to the deformation modulus of foundation are taken as objective functions, feasibility robust constraint of stress is taken into account with the consideration of uncertainty of foundation deformation modulus, and a robust optimization model for shape design of arch dams is established based on strain energy. A formula of sensitivity of dam strain energy to deformation modulus of foundation is derived and a relevant algorithm is proposed. The optimization of a planned arch dam indicates that, the dam strain energy and its sensitivity to foundation deformation modulus of optimal design are reduced 2.29% and 15.51%, respectively, of that of initial design, and the validity of the proposed model is demonstrated.

Abstract: In this paper, the structural optimization problem of a deployable cable-frame antenna consisting of a cable network and a supporting frame is discussed in detail. Firstly, the initial equilibrium problem of the cable-frame antenna structure is discussed with emphasis on the realization convenience. An optimization model is proposed to get a set of uniformly distributed cable pretensions whilst satisfying the surface precision requirement. Secondly, the optimization of the member size and cable tensions are integrated in one optimization model in which both folded and deployed status are considered. Finally, a 10-meter antenna is optimized with good results which indicates that the proposed method is feasible and effective.