Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
Tải xuống
"Công trường xây dựng" là phạm vi khu vực diễn ra các hoạt động xây dựng đã được sự cho phép của chính quyền. Các thành phần cơ bản hình thành một công trường xây dựng là: Khu lán trại dành cho cán bộ, công nhân; khu vực tập kết vật tư vật liệu; khu vực mà công trình xây dựng được xây dựng trực tiếp trên đó. | 196 Basic Coastal Engineering Moored floating structures Rubble mound structures both massive structures and rubble mound veneers to protect embankments Vertical-faced rigid structures Some structures may combine the types mentioned above. An example would be a vertical faced concrete caisson placed on a submerged rubble mound platform that provides a stable base against wave attack and bottom scour. There are two primary concerns in the design of any coastal structure. One is the structural aspects which address the stability of the structure when exposed to design hydrodynamic and other loadings. The other is the functional aspects which focus on the geometry of the structure to see that it satisfies the particular design function s such as keeping the wave heights in the lee of the structure reduced to an acceptable level or helping to retain a sufficiently wide beach at the desired location. This chapter deals primarily with the first concern but addresses some aspects of the second concern which are also covered in the next chapter. For rigid structures such as piles vertical-faced walls and large submerged structures our focus is on determining the loadings on the structure. This leads to the analysis for design stresses which is a classical civil-structural engineering concern. On the other hand for a structure such as a rubble mound breakwater our concern is to determine the stone unit size and related structure component sizes required to withstand attack by a given design wave and water level. 7.1 Hydrodynamic Forces in Unsteady Flow Water particle motion in a wave is continually unsteady flow. When this unsteady flow interacts with a submerged solid body a force is exerted on the body owing both to the particle flow velocity and the flow acceleration. The flow velocity causes a drag force Fd to act on the submerged body owing to frictional shear stress and normal pressure that is typically given by Fd Cd pAu2 7.1 For streamlined bodies such as an airfoil
