《Bridge engineering handbook桥梁工程手册-27墩与柱》.pdf

27 Piers and Columns 27.1 Introduction 27.2 Structural Types General • Selection Criteria 27.3 Design Loads Live Loads • Thermal Forces 27.4 Design Criteria Overview • Slenderness and Second-Order Effect • Jinrong Wang Concrete Piers and Columns • Steel and Composite URS Greiner Columns 27.1 Introduction Piers provide vertical supports for spans at intermediate points and perform two main functions: transferring superstructure vertical loads to the foundations and resisting horizontal forces acting on the bridge. Although piers are traditionally designed to resist vertical loads, it is becoming more and more common to design piers to resist high lateral loads caused by seismic events. Even in some low seismic areas, designers are paying more attention to the ductility aspect of the design. Piers are predominantly constructed using reinforced concrete. Steel, to a lesser degree, is also used for piers. Steel tubes filled with concrete (composite) columns have gained more attention recently. This chapter deals only with piers or columns for conventional bridges, such as grade separations, overcrossings, overheads, underpasses, and simple river crossings. Reinforced concrete columns will be discussed in detail while steel and composite columns will be briefly discussed. Substructures for arch, suspension, segmental, cable-stayed, and movable bridges