Chapter 1. Introduction Chapter 2. Structural Steel Chapter 3. Plastic Behavior at the Cross-Section Level Chapter 4. Concepts of Plastic Analysis Chapter 5. Systematic Methods of Plastic Analysis Chapter 6. Applications of Plastic Analysis Chapter 7. Building Code Seismic Design Philosophy Chapter 8. Design of Ductile Moment-Resisting Frames Chapter 9. Design of Ductile Concentrically Braced Frames Chapter 10. Design of Ductile Eccentrically Braced Frames Chapter 11. Design of Ductile Buckling-Restrained Braced Frames Chapter 12. Design of Ductile Steel Plate Shear Walls Chapter 13. Other Ductile Steel Energy Dissipating Systems Chapter 14. Stability and Rotation Capacity of Steel Beams Index

Ductile design of steel structures

The performance of concentrically braced steel frames and moment resisting steel frames during the January 17, 1994, Northridge, California, earthquake is examined. Most of the observations made du...

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Performance of steel structures during the 1994 Northridge earthquake

This paper describes an experimental study on the seismic performance of concentrically braced steel frames made with cold-formed rectangular tubular bracing members. A total of 24 quasistatic cyclic tests were performed on full size X bracing and single diagonal bracing systems. Two loading sequences were considered: a symmetrical stepwise increasing deformation sequence and a displacement history obtained from nonlinear dynamic analyses of typical braced steel frames. All specimens buckled out-of the plane of the frame and the tests were interrupted when fracture of the braces occurred in the region of highest curvature. For X bracing, the results clearly show that the effective length of the braces can be used to determine their compression strength and to characterize their hysteretic response, including energy dissipation capability. Simplified models are proposed to predict the out-of-plane deformation of the braces as a function of the ductility level. These models are then used to develop an empir...

Seismic response of concentrically braced steel frames made with rectangular hollow bracing members

Results from 18 large-scale tests of steel bracing members are presented to examine their inelastic buckling and fracture behavior as related to the seismic design of concentrically braced frames. The brace specimens include square hollow structural shapes (HSS), pipe, and wide-flange sections. The effect of various parameters, including width–thickness and slenderness ratios, cross-section shape, loading history, loading rate, and grout fill on the performance of these braces is investigated. Among these parameters, loading history, width–thickness ratio and slenderness ratio are shown to have the largest influence on brace ductility. The test data suggest that for some HSS and pipe specimens, current seismic design provision limits on maximum width–thickness ratios may not provide sufficient ductility for seismic design. Effects of loading rate are found to be insignificant, and the grout fill is shown to provide a modest improvement in cyclic ductility. Measurements of brace stiffness, tensile strength...

Experimental Investigation of Inelastic Cyclic Buckling and Fracture of Steel Braces

http://spiral.imperial.ac.uk/bitstream/10044/1/15272/2/Engineering%20Structures_32_2_2010.pdf

Cyclic testing and numerical modelling of carbon steel and stainless steel tubular bracing members

An experimental study is presented of the inelastic behavior of axially loaded steel members subjected to repeated buckling and stretching. Tests on 24 commercially available steel struts commonly used as bracing members are reported. A large variety of shapes were tested including wide flanges, structural tees, double-angles, a double-channel, and thick and thin-walled square and round tubes. The boundary conditions were of two types, pinned-pinned and fixed-pinned, while the effective slenderness ratios were either 40, 80, or 120. The effects were investigated of loading patterns, end conditions, cross-sectional shapes, and slenderness ratios on the hysteresis response of members. An explanation is given regarding the fundamental mechanisms responsible for the observed degradation in the buckling load capacity during inelastic cycling.

Steel Struts under Severe Cyclic Loadings

A six-year experiment using an unconventional teaching approach and advanced structural engineering software to teach structures to architecture students has been conducted at the University of California, Berkeley, and has resulted in the formulation of a comprehensive model for teaching structures. This model may help solve the general problem of effectively teaching and integrating structures within an architecture curriculum. This article discusses conventional teaching approaches and their shortcomings, outlines the new model by presenting twelve foundational tenets, briefly describes finite element analysis, and argues for the appropriateness of using finite element analysis as a tool for learning. The article then examines the detailed implementation of the model in a single course, and it concludes by describing a prototype curriculum that has grown from the teaching model and its underlying philosophies.

A Model for Teaching Structures: Finite Element Analysis in Architectural Education

The innovative bridge design discussed in this paper is a long-span curved cable-stayed bridge with a single canted tower. The superstructure of the bridge consists of a multicell steel box girder with composite concrete-steel deck. The single tower of the bridge is a multicell steel box with the core cell dedicated to the service elevator and stairs. The outer cells of the single tower are filled with high-strength concrete to provide strength and stiffness in a composite action. The foundation of the main single tower is a solid footing embedded in the rock. Inelastic time-history analyses were conducted to complete the seismic design and establish expected seismic performance. After a description of the architectural design, seismological, geotechnical, and structural design aspects are discussed, and a summary of seismic design and expected seismic response of the curved cable-stayed bridge concept is presented.

Seismic and structural engineering of a curved cable-stayed bridge

Preliminary results from a project studying the behavior of a hidden timber tension connections are presented. The connection consists of a threaded steel rod inserted in a longitudinal hole along the central axis of a timber member, with a bearing plate and nut fitted on to the end of the rod in a specially cut mortise. This assembly was tested under pure axial load statically applied to the steel rod and the timber member. Observed failure modes are described and photographic documentation of failed connections is presented. Failure mode distribution is shown as a function of two physical parameters, the size of the bearing plate and the distance from the bearing plate to the end of the member, and a comparison is made with theoretical failure-mode domains derived from National Design Specification allowable stresses. The correlation of variations in the physical parameters with ultimate strength and ductility is also discussed. Initial results show the connection to be predictable, ductile, and potenti...

Parameter study of an internal timber tension connection

The International Building Code (IBC) and the California Building Code (CBC) both recognize four basic types of steel seismic resistant frames; moment frames, concentrically braced frames, shear walls and eccentrically braced frames Based on specified geometries and detailing, the seismic performance of these steel frames is well understood In 2011, the authors designed an innovative steel braced frame system with tapering members in the general shape of a branching tree as a seismic retrofit solution to an existing four story “lift-slab” building Located in the seismically active San Francisco Bay Area of California, a frame of this configuration, not covered by the governing codes, would typically require model or full scale testing to obtain jurisdiction approval This paper describes how the theories, protocols, and code requirements of eccentrically braced frames (EBFs) were employed to satisfy the 2009 International Building Code (IBC) and the 2010 California Building Code (CBC) for seismically resistant steel frames and permit construction of these nonconforming geometries Keywords—Eccentrically Braced Frame, Lift Slab Construction, Seismic Retrofit, Shear Link, Steel Design

R. Gary Black

Papers

Steel Struts under Severe Cyclic Loadings

A Model for Teaching Structures: Finite Element Analysis in Architectural Education

Seismic and structural engineering of a curved cable-stayed bridge

Parameter study of an internal timber tension connection

Design of Seismically Resistant Tree-Branching Steel Frames Using Theory and Design Guides for Eccentrically Braced Frames