Connections In Steel Buildings Research Articles

Hysteretic behaviors of square hollow column-truss beam-diagonal brace connections in steel buildings

This paper presents a novel square hollow column-truss beam connections incorporating diagonal braces, aimed at enabling accurate and efficient onsite assembly of modular, multi-story, and high-rise prefabricated steel structures. The hysteretic behavior of these connections was assessed through experimental study of ten cross-shaped specimens. Based on the experimental study, the load-displacement curve, ultimate bearing capacity, ductility and energy dissipation capacity were carefully examined. The test results show that with different combinations of critical components, three distinct failure modes including beam, column, and diagonal brace failure were demonstrated. For specimens without diagonal braces, the dominating failures were concentrated either on the beam or the column regions, and the hysteretic behavior of specimens with beam failure mode was superior than that of specimens with column failure mode. With incorporation of the diagonal braces in the connections, the failure region of specimens was shifted from the truss beam or the column to the braces, and the stiffness and load capacity of the connection were significantly improved. In addition, finite element model was established, and the accuracy of the numerical simulation results was verified by test results. Finally, based on the experimental and finite element analysis (FEA) results, the strategy for controlling the occurrence location and sequence of critical damage of such connections were proposed.

An Overview of Commonly Used Steel Beam-Column Connection in Indonesia for Low-Rise Building

The Indonesian seismic provision for steel structures was initiated in 2002. The use of steel has also been increasing as a choice of structural material since then. However, there are still many weaknesses in the seismic design of steel structures that have been carried out so far. A lot of beam-column connections in steel buildings in Indonesia use a haunch in a moment-resisting connection system. Haunched systems are not described in AISC 358 as permitted connections for earthquake-resistant buildings. Recently, Europe publishes European Prequalified Steel Joints (EqualJoints). There are four types of connections discussed, and one of them is the haunched type connections. The haunched connection meets the seismic requirements to be suitable for use as an earthquake-resistant connection in Europe. This can be used as a reference if we are going to design a haunched connection in Indonesia. However, special attention should be paid to the details. The bolt configuration, the thickness of the end plates, and the shape of the haunch are not like those commonly used in Indonesia, there must be improvements to be adjusted in EqualJoints. So that the performance of the connection against earthquakes becomes more guaranteed.

Comparison Between Different Steel Codes in Design of Bolted Connection Under Shear and Tension.(Dept.C)

The structural design codes of the different countries provide engineers with data and procedures for designing different structural components. In this paper, the American AISC, the Egyptian ECP, and the new European Code for Construction of Steel Structures (Eurocode 3) were compared in terms of design principles for bolted connections in steel buildings. This study focuses on the resistance capacity of connections in one of the following loading cases: axial tension, shear and axial tension and shear combinations. Similarities and variations in strength measures were recognized to allow rapid learning of the codes as well as the expressions and limits provided in ECP, EC3, and AISC codes. Analysis using simple tables and curves and design equations indicated that allowable stress and safety variables were directly correlated with one another wherever possible. A general program with Visual Basic.NET programming language was performed for reference. A steel program was created to obtain design connections and present design charts. Several diagrams were drawn.

Displacement-dependent nonlinear damping model in steel buildings with bolted joints

The stick–slip phenomenon is commonly found at structural connections in steel buildings. It is a major damping mechanism in a structure with bolted joints and makes a significant contribution to the total structural damping. This article reviews the stick–slip damping model of an elastic single-degree-of-freedom system with one stick–slip component. It is observed that the damping ratios of the system with the stick–slip mechanism first quickly increase when experiencing a very small displacement and then slowly decrease. After the number of activated slip surfaces is assumed to be a linear function related to the structural displacement, the equivalent damping ratios of a structural system with numerous stick–slip components are derived. However, this displacement-dependent damping model is very difficult to be used for a structural dynamic analysis due to its inherent complexity. Therefore, a new displacement-dependent damping model for a structural dynamic analysis is proposed based on the viscous damping. A high-rise steel moment resisting frame with bolted joints subjected to an earthquake ground motion is taken as an example to verify the proposed method.

Studies on the Behavior of Steel Single-Plate Beam End Connections in a Fire

This paper summarizes the results of a recently completed research study on the behavior of simple beam end framing connections in steel buildings subjected to fire. Connections are critical elements in maintaining the integrity of a structure during a fire, but there are still many aspects of connection behavior in a fire that are not well understood. In the USA, one of the most common types of simple beam end framing connections is the single-plate connection, which was the subject of this study.In this research investigation, a series of experiments were conducted on connection subassemblies at elevated temperatures to understand and characterize connection stiffness, strength and deformation capacity, and to validate predictions of connection capacity developed by computational and design models. Three-dimensional finite element (FE) connection models were developed and these models were evaluated by comparing with experimental data. The FE models were then used to conduct an extensive series of parameter studies that investigated the impact of several key variables on connection response to the heating and cooling stages of a fire.This paper describes key aspects of this study, including the experiments, development of FE models and parametric studies. The paper highlights the results of the study that provide important insights into connection behavior during a fire and the implications of these results for design.

Web‐based tutor for interactive design of connections in steel buildings

AbstractThere are a large number of connection types in steel structures. This is an area where students cannot get enough in the classroom. Design of each steel connection type is unique. At the same, there are similarities in designs of various connection types. These two factors plus the open‐ended nature of the design can make the learning of so many different types of connections both challenging and tedious. While a number of tools are available to help teach design of connections there is no interactive online tool for teaching and learning of design of connections in steel structures. In this article a novel interactive approach and a Java applet, called Connection Tutor, is presented for design of a variety of connections in steel structures. Connection Tutor is intended to be used as a user‐friendly supplement in teaching design of connections in steel structures. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 20: 568–577, 2012

Effects of low‐cycle fatigue on a 10‐storey steel building

AbstractFollowing the Northridge Earthquake in 1994, the SAC project was initiated as a joint venture between Structural Engineers Association of California (SEAOC), Applied Technology Council (ATC), and Consortium of Universities for Research in Earthquake engineering (CUREe) to investigate the causes of widespread damage observed in the connections of steel moment frame buildings. The published results of these studies concentrated on local connection defects that potentially initiated the observed cracks. It was also considered that much of the observed connection damage was the result of yielding of the material in the connection region and the formation of plastic hinges. However, damage to some buildings could not be reconciled by the use of these failure mechanisms. This has led to a renewed interest in the effects of low‐cycle fatigue on the members and connections in steel buildings that are either elastic or have been driven into the weakly nonlinear range.The current paper is focused on the effect of low‐cycle fatigue in the connection damage observed in a 10‐storey steel building following the Northridge Earthquake. A comprehensive fatigue analysis procedure is developed based on the Palmgren–Miner method and S–N curves established for the high‐cycle fatigue range are extended to the low‐cycle region using the limited test results that are available. Fatigue analysis is performed at critical locations of a representative moment frame using the established procedure. Finally, the pattern of cumulative fatigue at critical connections and the observed damage are compared. Results of this analytical study indicate that the effect of low‐cycle fatigue may be significant in evaluating and predicting various types of connection damage similar to that observed in the steel moment frames following the Northridge Earthquake. Copyright © 2010 John Wiley & Sons, Ltd.

テーマ特集 溶接・接合分野における新しい技術 限界状態設計法による鋼構造建築の溶接接合設計

テーマ特集 溶接・接合分野における新しい技術 限界状態設計法による鋼構造建築の溶接接合設計

Interactive microcomputer-aided design of shop-welded and field-bolted beam-column connections

A microcomputer-aided design (MicroCAD) system has been developed for interactive design of connections in steel buildings made of standard rolled l-sections, called Steelcon. Design of different connections is based on the American Institute of Steel Construction specification. Connecting elements may be plates, angles, or T-sections. Connectors may be bolts or welds. The MicroCAD system can display/plot any isometric view of the connection plus the orthographic views, i.e. front, side, and top views. The application of the MicroCAD system to the design of simple (type 2) shop-welded and field-bolted beam-column angle and plate connections is discussed. Microcomputer graphics for displaying the isometric and orthographic views including the dimensions and designation are presented. This MicroCAD system can be used effectively for practical design of connections in steel buildings.

Microcomputer‐Aided Design and Drafting of Moment‐Resisting Connections in Steel Buildings

A microcomputer‐aided system has been developed for interactive design and drafting of connections in steel buildings made of standard. rolled‐I sections, called STEELCON. The basis of design is AISC specification. In addition to interactive design, STEELCON can displaylplot any isometric view of the connection plus three orthographic views, i.e., front, side, and top face views. The orthographic views show all the necessary details for fabrication and construction of the connections. Interactive design and drafting of two different moment resisting connections are presented. They are the shop welded and field bolted framed flange plate connection and the shop and field welded flange plate connection.

A MICROCAD system for design of steel connections—II. Applications

A microcomputer-aided design (MICROCAD) system is presented for interactive design of connections in steel buildings made of standard rolled I-sections. Design of different connections is based on the American Institute of Steel Construction specification. Connecting elements may be plates, angles, or T-sections. Connectors may be bolts or welds. The MICROCAD system can display/plot any isometric view of the connection plus the orthographic views, i.e. front, side, and top views. Program structure and graphic algorithms for the MICROCAD system are presented in an accompanying paper. In this paper applications of the MICROCAD system for design of bolted and welded connections are presented. Different menus available to the user are discussed. Microcomputer graphics for displaying the orthographic views with dimensions and designations, and isometric views are presented. This MICROCAD system can be used effectively for practical design of connections in steel buildings

A MICROCAD system for design of steel connections—I. Program structure and graphic algorithms

A microcomputer-aided design (MICROCAD) system is presented for interactive design of connections in steel buildings made of standard rolled I-sections. Design of different types of connections is based on the American Institute of Steel Construction Specification. Connecting elements may be plates, angles, or T-sections. Connectors may be bolts or welds. The MICROCAD system can display/plot any isometric view of the connection plus three orthographic views, i.e. front, side, and top views. Program structure, face frame representation, and graphic algorithms are presented. An efficient priority list algorithm with back-face elimination is developed for the orthographic views. The painter's algorithm is used to remove hidden lines. A five-test algorithm is developed for efficient drawing of the isometric views. Application of the MICROCAD system for practical design of steel connections is presented in an accompanying paper.