Current Issue : October - December Volume : 2020 Issue Number : 4 Articles : 5 Articles
A structural analysis method is proposed in this paper for cable-beam composite structure with a large number of cable elements;\nit can improve computational efficiency and accuracy. Firstly, we use a structural division method to divide the whole cable-beam\nstructure into inner cablenet system and edge cablenet-beam system. Because inner cablenet is a pure cablenet structure with given\nshape and topology, balance matrix analysis method is used to help obtain the best pretension distribution of it with the evenness\nas objective. For edge cablenet-beam system, with obtaining equilibrium forces of inner cablenetâ??s pretensions as goal, an iterative\npretension losses compensation calculation combined with nonlinear finite element method and balance matrix analysis method\nis used for edge cablenet to adjust its pretension distribution and make the whole cablenet system keep its preset ideal shape under\ninfluence of beamsâ?? deformations. Because edge cablenet-beam system has a lot less cable elements than overall structure, its\nnonlinear finite element calculations are much easier and faster than those for the whole cable-beam composite structure. In order\nto verify the above methodâ??s validity, it is used for a spaceborne cablenet deployable antenna example, and the computed results\nindicate that the method is feasible....
To study the size effect of nuclear power containment concrete (NPCC) under compressive dynamic performance, the cube\nconcrete specimens with 3 different cube sizes were measured at 10 different loading strain rates using a hydraulic servo, and the\nfailure mode and compressive strength of NPCC were compared and analyzed under different loading conditions. Based on the\ncomparative analysis of experiment results, the following conclusions can be drawn: the effect of loading strain rate has caused\nNPCC to develop from static strain rate, mainly cement cementitious layer damage and uniform distribution of cracks, to dynamic\nstrain rate, where there are partial coarse aggregate failures and oblique cracks as the main crack distribution. Due to the size effect,\nthe integrity of large-scale NPCC specimen after compression failure is relatively high. With the increase of loading strain rate and\ndecrease of cube size, compressive strength of NPCC is gradually increased, and, with the increase of loading strain rate, the size\neffect on the mechanical properties of NPCC becomes more significant. Moreover, this paper quantitatively analyzes the influence\nof the coupling effect of strain rate and size effect on the compressive strength of NPCC, and its mechanism is discussed in depth.\nThe research results are of great significance to the safety of nuclear power concrete containment....
According to the advantages of high tensile resistance and high shear strength of composite steel plate, a new antiexplosion\nprotection method of composite steel plate lining structure is put forward. The numerical model of explosion impact of subway\ntunnel with composite steel plate lining structure was established by dynamic analysis software. The transient dynamic response of\nlining structure with the composite steel plate was simulated when explosion occurred. The research results show that the\ninfluence of explosive quantity on each point of composite steel plate lining structure is different and the change of acceleration\nnear the centre of the detonation source is generally greater than the multiple of the increase of explosive quantity. The increase of\nvelocity and displacement is basically consistent with the quantity of explosive. The influence of axial stress on the lining structure\nis the least, and the influence of the lining structure is greater in the y-direction than in the x-direction. The research results can\nprovide the plan and basis for the emergency response of the subway tunnel....
The steel plate-concrete structure, with its advantages of modular construction, good seismic capacity, and strong impact resistance, has\nbeen gradually replacing the reinforced concrete structure in the containment vessel and internal workshop structure of nuclear power\nplants in recent years. In this study, the out-of-plane single-point loading test and parametric finite element simulation analysis were\nconducted on five steel plate-concrete wall slab specimens with different stud spacings, shear span ratios, and steel contents. Results\nshowed that the steel plate-concrete wall slab under the out-of-plane load had the same failure mode as that of an ordinary reinforced\nconcrete wall. The out-of-plane shear capacity of the steel plate-concrete wall slab increased significantly in the case of numerous studs.\nWith the increase in shear span ratio, steel plate-concrete members suffered a bending failure. When the steel content was low, they had\ndiagonal tension failure, such as a rare-reinforced concrete wall. The out-of-plane bending and shear mechanism of the steel plateconcrete\nshear wall was studied theoretically, and the calculation formulas of the bending and shearing capacities were derived....
A reduction in potable water demand in buildings could be made by using non-potable\nwater for certain uses, such as flushing toilets. This represents a sustainable strategy that results\nin potable water savings while also using an underutilised resource. This work assesses the use of\npermeable interlocking concrete pavement to filter stormwater that could be used for non-potable\npurposes in buildings. Two pavement model systems were tested. One of the model systems presents\na filter course layer with coarse sand and the other model system has no filter course layer. In\norder to evaluate the filtering capacity, the model systems were exposed to rain events. The amount\nof water infiltrated through the layers was measured to represent the potential quantity available\nfor use. Stormwater runoff samples were collected from a parking lot paved with impermeable\ninterlocked blocks and then, these were tested in both model systems. Water samples were subjected\nto quality tests according to the parameters recommended by the Brazilian NationalWater Agency.\nThe model system with no filter course showed filtering capacity higher (88.1%) than the one with\na filter course layer (78.8%). The model system with a filter course layer was able to reduce fecal\ncoliforms (54.7%), total suspended solids (62.5%), biochemical oxygen demand (78.8%), and total\nphosphorus concentrations (55.6%). Biochemical oxygen demand (42.4%) and total phosphorus\nconcentrations (44.4%) increased in the model system with no filter course layer. In conclusion, one\ncan state that the filter course layer used in permeable interlocking concrete pavement can contribute\nto decreasing pollutants and can improve stormwater quality. The use of permeable interlocking\nconcrete pavement showed to be a potential alternative for filtering stormwater prior to subsequent\ntreatment for non-potable uses in buildings....
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