Showing papers on "Earthquake resistant structures published in 1974"

Hysteretic dampers for earthquake-resistant structures

Abstract: The earthquake resistance of many structures can be increased by the inclusion of special components which act as hysteretic dampers. During moderately severe earthquakes these dampers act as stiff members which reduce structural deformations, while during very severe earthquakes the dampers act as energy absorbers which limit the quasi-resonant build-up of structural deformations and forces. The hysteretic dampers are not required to withstand the main structural loads, and may therefore be optimized for their required stiffness and energy-absorbing features. On the other hand, the main structural components no longer require large energy-absorbing capacities and they may therefore be optimized for their required stiffnesses and load-bearing features. For many structures this separation of component functions should lead to increased reliability at a lower initial cost. Under earthquake attack structural damage should be reduced. Non-structural damage should be lower during moderately severe earthquakes, and for certain types of structure it should also be lower for very severe earthquakes. Various ways in which hysteretic dampers may be utilized in structures are discussed briefly. The development of several types of high-capacity, low-cost hysteretic damper, suitable for use in structures, is described. The dampers utilize solid steel beams deformed plastically in various combinations of torsional, flexural and shear deformations.

Reinforced concrete designer's handbook

Abstract: This handbook consists of two parts: Part 1 which consists of seven sections and Part 2 which consists of design tables and commentary, bibliographic references, and an index Section 1 of Part 1 reviews general factors, economical structures, and drawings Section 2 reviews safety factos, loads, and pressures Section 3, which reviews structural analysis, covers beams and cantilevers, slabs, rectangular and non-rectangular panels, framed structures, columns, bending, earthquake-resistant structures, frames, and arches Section 4 reviews materials and stresses, and covers concrete, stresses in concrete, and reinforcement Section 5 (resistance of structural members) covers cross-sections of members, beams, slabs, limit-state, load-factor design, liquid-containing structures, shearing, torsion, columns, bending, thrust, tension, walls, joints, and intersections Section 6 (structures and foundations) covers buildings, bridges, culverts, subways, bearings, hinges, joints, concrete roads, containers, tanks, bunks, silos, industrial structures, chimneys, retaining walls, piles, walls, wharves and jetties Section 7 focuses on some areas where computers are being applied Program such as GENESYS, ICES, DECIDE and OASYS-45 are discussed

An investigation of the effectiveness of existing bridge design methodology in providing adequate structural resistance to seismic disturbances. phase iii: analytical investigations of seismic response of short, single, or multiple-span highway bridges

Abstract: This report is the second in a series to result from the investigation, "An Investigation of the Effectiveness of Existing Bridge Design Methodology in Providing Adequate Structural Resistance to Seismic Disturbances", sponsored by nonlinear analytical procedures are described for Administration. Descriptions are given to the analytical investigations of the seismic response of long, multiple-span, highway bridge structures of the type which suffered heavy damages during the San Fernando earthquake of February 9, 1971. Linear and nonlinear mathematical modeling of this type of bridge structural system is presented. A three-dimensional elasto-plastic flexural column model suitable for modeling the coupled inelastic behavior of reinforced concrete bridge columns is described in detail. A nonlinear mathematical model for simulating the nonlinear discontinuous behavior of bridge expansion joints is also presented. Then, appropriate linear and determining the seismic response of this type of bridge structure. Nonlinear seismic responses are presented for three prototype long, multiple-span, reinforced concrete highway overcrossing structures. Parameter studies carried out on these bridges are described, and the analytical results are presented, discussed, and correlated with the apparent prototype behavior observed during the San Fernando earthquake. Finally, based on the analytical seismic responses presented, general conclusions and recommendations related to the fundamental seismic design methodology of long, multiple-span highway bridges are deduced and summarized. This report is the second in a series. The others in the series are: Phase No.: I, FHWA No.: 73-13, Short Title: Literature Survey, NTIS (PB) No. (if available): (not yet available). /FHWA/

Aseismic Design for Electrical Facilities

Abstract: The earthquake resistant design of electrical generation and transmission facilities is not necessarily achieved using static loading criteria. The San Fernando earthquake of February 1971 demonstrated that more realistic design criteria are required to assess the effects of earthquake motions. An approach is presented for establishing regional aseismic design criteria for non-nuclear electrical facilities located in an area of high seismicity and faulting, and three zones were identified in which most-severe, less-severe, and moderate earthquake shaking is anticipated. The degree of hazard was expressed for purposes of design, in terms of design spectra and scaled accelerograms corresponding to the “average maximum earthquake.” The design spectra and accelerograms provide the basis for qualification of equipment and for analysis of structures and equipment using the response spectrum technique.