Earthquake resistant structures

Abstract: Chapter 1. Introduction Chapter 2. Performance requirements and compliance criteria, 2.1 Performance requirements for new designs in Eurocode 8 and associated seismic hazard levels, 2.2 Compliance criteria for the performance requirements and their implementation, 2.3 Exemption from the application of Eurocode 8 Chapter 3. Seismic Actions, 3.1 Ground conditions, 3.2 Seismic action,3.3 Displacement Response Spectra Chapter 4. Design of Buildings, 4.1 Scope, 4.2 Conception of structures for earthquake resistant buildings, 4.3 Structural regularity and implications for the design, 4.4 Combination of gravity loads and other actions with the design seismic action, 4.5 Methods of analysis, 4.6 Modeling of buildings for linear analysis, 4.7 Modeling of buildings for nonlinear analysis, 4.8 Analysis for accidental torsional effects, 4.9 Combination of the effects of the components of the seismic action, 4.10 "Primary" vs. "secondary" seismic elements, 4.11 Verifications, 4.12 Special rules for frame systems with masonry infills Chapter 5. Design and detailing rules for concrete buildings, 5.1 Scope, 5.2 Types of concrete elements-Definition of their "critical regions", 5.3 Types of structural systems for earthquake resistance of concrete buildings, 5.4 Design concepts: Design for strength or for ductility and energy dissipation-Ductility Classes, 5.5 Behaviour factor q of concrete buildings designed for energy dissipation, 5.6 Design strategy for energy dissipation, 5.7 Detailing rules for local ductility of concrete members, 5.8 Special rules for large walls in structural systems of large lightly reinforced walls, 5.9 Special rules for concrete systems with masonry or concrete infills, 5.10 Design and detailing of foundation elements Chapter 6. Design and detailing rules for steel buildings, 6.1 Scope, 6.2 Dissipative versus low dissipative structures, 6.3 Capacity design principle, 6.4 Design for local energy dissipation in the elements and their connections, 6.5 Design rules aiming at the realisation of dissipative zones, 6.6 Background of the deformation capacity required by Eurocode 8, 6.7 Design against localization of strains, 6.8 Design for global dissipative behaviour of structures, 6.9 Moment resisting frames, 6.10 Frames with concentric bracings, 6.11 Frames with eccentric bracings, 6.12 Moment resisting frames with infills, 6.13 Control of design and construction Chapter 7. Design and detailing of composite steel-concrete buildings, 7.1 Introductory remark, 7.2 Degree of composite character, 7.3 Materials, 7.4 Design for local energy dissipation in the elements and their connections, 7.5 Design for global dissipative behaviour of structures, 7.6 Properties of composite sections for analysis of structures and for resistance checks, 7.7 Composite connections in dissipative zones, 7.8 Rules for members, 7.9 Design of columns, 7.10 Steel beams composite with slab, 7.11 Design and detailing rules for moment frames, 7.12 Composite concentrically braced frames, 7.13 Composite eccentrically braced frames, 7.14 Reinforced concrete shear walls composite with structural steel elements, 7.15 Composite or concrete shear walls coupled by steel or composite beams, 7.16 Composite steel plates shear walls Chapter 8. Design and detailing rules for timber buildings, 8.1 Scope, 8.2 General concepts in earthquake resistant timber buildings, 8.3 Materials and properties of dissipative zones, 8.4 Ductility classes and behaviour factors, 8.5 Detailing, 8.6 Safety verifications Chapter 9. Seismic design with base isolation, 9.1 Introduction, 9.2 Dynamics of seismic isolation, 9.3 Design criteria, 9.4 Seismic isolation systems and devices, 9.5 Modelling and analysis procedures, 9.6 Safety criteria and verifications, 9.7 Design seismic action effects on fixed base and isolated buildings Chapter 10. Foundations, retaining structures and geotechnical aspects, 10.1 Introduction, 10.2 Seismic action, 10.3 Ground properties, 10.4 Requ

Abstract: The method uses the concept of yield acceleration but is based on the evaluation of the dynamic response of the embankment rather than a rigid body behavior. The yield accelerations, for a potential sliding mass, is estimated on the basis of the static undrained shear strength (with some reduction due to effects of cycling) using pseudostatic methods of stability analysis. The permanent deformations are estimated by numerical double integration of the time history of induced accelerations for various depths of the potential sliding mass. Design curves are presented that were developed on the basis of finite element response computations of embankments subjected to base accelerations representing earthquakes of magnitudes ranging between 6-4 and 8-2. The simplified procedure is illustrated by an example computation. The permanent deformations are estimated for a 135-ft (40-m) high sandy clay embankment that was shaken by a magnitude 8-2 earthquake and the results are compared with the observed field behavior.

Abstract: Building code provisions for the seismic resistant design of structures incorporate two basic types of requirements. The first of these is very similar to the code requirements for most other types of loading and comprises specification of minimum permissible strength and structural stiffness. The second is unique to design for seismic resistance and consists of prescriptive criteria on the detailing practice for the structural elements. While strength and stiffness requirements have been part of building codes for nearly 100 years, these detailing practice requirements, which include such things as prescription of the volumetric ratio and spacing of reinforcing in concrete structures, and permissible width/thickness ratios for elements of members in steel structures are a recent addition to the code. They were first introduced into the codes in the late 1960s and primarily affected the design of reinforced concrete structures. However, as researchers have continued to understand the importance of detailing to seismic performance and actual earthquakes have made clear to the profession that poor detailing practice directly leads to adverse structural behavior, the volume and complexity of these detailing requirements has steadily increased. Extensive detailing requirements for reinforced concrete structures were introduced into the building codes following the 1971 San Fernando earthquake. Requirements for timber and masonry structures were also added throughout the 1970s and 1980s as relatively modest earthquakes, such as the 1979 Imperial Valley, California; 1983 Coalinga, California and 1984 Morgan Hill, California earthquakes indicated problems associated with improperly detailed structures of this construction type. However, relatively few requirements for detailing of steel structures were placed in the codes during this period, largely because there were few examples of poor performance of steel structures. This began to change with the 1985 Mexico City, Mexico earthquake in which several large steel buildings in the lake bed region of Mexico City collapsed. Additional requirements for detailing of steel structures were introduced following the 1987 Whittier Narrows, California earthquake. Most of these requirements pertained to the detailing of braced steel frames. The 1994 Northridge, California earthquake resulted in the introduction of extensive code detailing requirements for moment-resisting steel frames. Immediately following the earthquake, brittle fractures were discovered in the beam to column connections of several buildings in the San Fernando Valley (Figures 1, 2). This damage was

Abstract: The factors to be considered in the earthquake-resistant design of dams are discussed and defensive measures which may be taken to mitigate the effects of these factors are summarized. Available information concerning the field performance of dams during earthquakes is reviewed and conclusions are drawn concerning the potential for earthquake-induced sliding for different types of construction materials and earthquake shaking intensities. Finally, available methods for evaluating the stability and deformations of the slopes of a dam due to earthquake shaking are reviewed and their applicability illustrated. Conclusions are drawn concerning the significance of the type of soil used for construction and the possibility of delayed failure, after the earthquake ground motions have stopped, due to pore water pressure re-distribution within an embankment. Suggestions are made concerning the appropriate role of analytical procedures in the overall assessment of the seismic stability of dams in relation to the un...

Abstract: Steel moment-resisting frames (MRFs) with posttensioned connections are constructed by posttensioning beams to columns using high strength strands. Top and seat angles are added to provide energy dissipation and redundancy under seismic loading. This new type of connection has several advantages, including the following: (1) field welding is not required; (2) the connection stiffness is similar to that of a welded connection; (3) the connection is self-centering; and (4) significant damage to the MRF is confined to the angles of the connection. An analytical model based on fiber elements was developed for these connections. Experimental test results were used to calibrate the model. The model was used for inelastic static analyses of interior connection subassembages as well as dynamic time history analyses of a six-story steel MRF. A self-centering capability and adequate stiffness, strength, and ductility were observed in the results of these analyses. Time history analysis results show that the seismic...