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更多“Plain concrete is formed from a hardened mixture of cement, water, fine aggregate, coarse aggregate …”相关的问题
Beams ：Beams are the structural elements that transmit the loads from floor slabs to vertical supporting columns. They are normally cast monolithically with the slabs and are structurally reinforced on one face, the lower tension side, or both the top and bottom faces. Floor Slabs ：Floor slabs are the main horizontal elements that transmit the moving live loads as well as the stationary dead loads to the vertical framing supports of a structure. They can be proportioned such that they act in one direction (one-way slabs) or proportioned so that they act in two perpendicular direction (two-way slabs). Foundations： Foundations are the structural concrete elements that transmit the weight of the superstructure to the supporting soil. They could be in many forms, the simplest being the isolated footing. It can be viewed as an inverted slab transmitting a distributed load from the soil to the column.
Concrete is strong in compression but weak in tension. Therefore, reinforcement is needed to resist the tensile stresses resulting from the loads. Additional reinforcement is occasionally used to reinforce the compression zone of concrete beam sections. Such steel is necessary for heavy loads in order to reduce long-term deflections. Reinforce concrete systems are composed of a variety of concrete structural elements that, when synthesized, produce a total system. The components can be broadly classified into: floor slabs, beams, columns, walls, and foundations. Beams are the structural elements that transmit the loads from floor slabs to vertical supporting columns. They are normally cast monolithically with the slabs and are structurally reinforced on one face, the lower tension side, or both the top and bottom faces.
Civil engineering is a branch of engineering that deals with the design and construction of structures that are intended to be stationary, such as buildings and houses, dams, tunnels, bridges, canals, sanitation systems and the stationary parts of transportation system-highways, airports, port facilities, and road bed for railroads. Among its subdivisions are structural engineering, dealing with permanent structures; hydraulic engineering, dealing with the flow of water and other fluids; and environmental/sanitary engineering, dealing with the water supply, water purification, and sewer systems; as well as urban planning and design. The term civil engineering originally came into use to distinguish it from military engineering. Civil engineering dealt with permanent structures for civilian use, whereas military engineering dealt with temporary structures for military use.
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 of the cement/water mix, resulting in hardened concrete. The finished product has high compressive strength, and low resistance to tension, such that its tensile strength is approximately one tenth of its compressive strength. Consequently, tensile and shear reinforcement in the tensile regions of sections has to be provided to compensate for the weak tension regions in the reinforced concrete element.
A、静脉吸入复合麻醉
B、蛛网膜下隙-硬膜外腔联合阻滞麻醉
C、腰丛+坐骨神经阻滞
D、骶管阻滞
A、气管表面麻醉时，可使用2%利多卡因并加入肾上腺素
B、硬膜外腔阻滞时，可使用2%利多卡因并加入肾上腺素
C、臂丛神经阻滞时，可使用0.5%罗哌卡因并加入α2受体激动剂
D、手指神经阻滞时，可使用1%利多卡因并加入肾上腺素
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