土木工程類(lèi)外文文獻(xiàn)翻譯1-建筑結(jié)構(gòu)-全文預(yù)覽
【正文】 hich introduces some simplifying assumptions ( semiprobabilistic methods ) . 。 (3) Cost of physical and material damage due to the failure of the construction。 (2)Number of human lives which can be threatened by this failure。 and corrosion. Computational methods used to verify structures with respect to the different safety 畢 業(yè) 設(shè) 計(jì) 11 conditions can be separated into: (1)Deterministic methods, in which the main parameters are considered as nonrandom parameters. (2)Probabilistic methods, in which the main parameters are considered as random parameters. Alternatively, with respect to the different use of factors of safety, putational methods can be separated into: (1)Allowable stress method, in which the stresses puted under maximum loads are pared with the strength of the material reduced by given safety factors. (2)Limit states method, in which the structure may be proportioned on the basis of its maximum strength. This strength, as determined by rational analysis, shall not be less than that required to support a factored load equal to the sum of the factored live load and dead load ( ultimate state ). The stresses corresponding to working ( service ) conditions with unfactored live and dead loads are pared with prescribed values ( service limit state ) . Fro m the four possible binations of the first two and second two methods, we can obtain some useful putational methods. Generally, two binations prevail: (1)deterministic methods, which make use of allowable stresses. (2)Probabilistic methods, which make use of limit states. The main advantage of probabilistic approaches is that, at least in theory, it is possible to scientifically take into account all random factors of safety, which are then bined to define the safety factor. probabilistic approaches depend upon : (1) Random distribution of strength of materials with respect to the conditions of fabrication and erection ( scatter of the values of mechanical properties through out the structure )。 elastic or plastic deformation or creep that cause a substantial change of the geometry of the structure。 and the articulated type of about m 179。 struck capacity ( 25 m 179。 畢 業(yè) 設(shè) 計(jì) 7 2 外文翻譯 Reinforced Concrete Plain concrete is formed from a hardened mixture of cement ,water ,fine aggregate, coarse aggregate (crushed stone or gravel),air, and often other admixtures. The plastic mix is placed and consolidated in the formwork, then cured to facilitate the acceleration of the chemical hydration reaction lf the cement/water mix, resulting in hardened concrete. The finished product has high pressive strength, and low resistance to tension, such that its tensile strength is approximately one tenth lf its pressive strength. Consequently, tensile and shear reinforcement in the tensile regions of sections has to be provided to pensate for the weak tension regions in the reinforced concrete element. It is this deviation in the position of a reinforces concrete section from the homogeneity of standard wood or steel sections that requires a modified approach to the basic principles of structural design. The two ponents of the heterogeneous reinforced concrete section are to be so arranged and proportioned that optimal use is made of the materials involved. This is possible because concrete can easily be given any desired shape by placing and pacting the wet mixture of the constituent ingredients are properly proportioned, the finished product bees strong, durable, and, in bination with the reinforcing bars, adaptable for use as main members of any structural system. The techniques necessary for placing concrete depend on the type of member to be cast: that is, whether it is a column, a bean,
畢業(yè)設(shè)計(jì)相關(guān)推薦
鄂ICP備17016276號(hào)-1