bluuebunny/crossref_metadata_2025 huggingface dataset:
Practical Approaches in Mill Building Columns Subjected to Heavy Crane Loads
Authors: Bendapudi Kasi V.
Published: April 2024

Since the turn of this century, the amount of analytical and experimental research in the area of column design has been extensive. While the information and results of such research is scattered and narrowly focused in very specialized areas, identification of this vast amount of relevant information available is often difficult. There is no legal code governing the design of heavy mill building columns and the designs are based on experience and judgment. Additionally, there are varying types of mill building columns due to assumptions and geometry. This has led to a design practice that varies from one designer to another, based on their experience and knowledge of the mill buildings. For a practicing engineer it is essential to analyze, integrate, and establish a logical and comprehensive design methodology and procedures. It is not possible to establish one generic approach applicable to all types of mill building columns. It is rather easier to deal independently with each type of these complex structural elements in achieving this goal. This paper presents a design methodology and procedures for "heavy mill building columns" subjected to heavy crane loads. For the purpose of this paper heavy crane loads are defined as loads imparted by cranes with lifting capacity ranges from 100 tons to 500 tons such as hot metal cranes. These columns consist of two or more shafts and are laced together to achieve composite behavior. The column bases are fully fixed and the roof trusses are simply supported at the top of the building shaft. The bottom chords of the trusses are braced the full length of the building. Other types of mill building columns are not included in the scope of this paper. Therefore, the procedures and methodology presented herein may not be directly applicable to any other type of mill building column.
Inelastic Design of Steel Girder Bridges
Authors: Barker Michael G.
Published: April 2024

This paper presents existing inelastic design procedures for steel girder bridges. Comparisons of the inelastic methods and the conventional methods are presented. This paper also discusses past and current analytical and experimental research for developing behavior models to extend inelastic design techniques for bridges comprising non-compact sections.
Buckling of Webs in Unsymmetric Plate Girders
Authors: Frank Karl H. , Helwig Todd A.
Published: April 2024

The elastic buckling behavior of unsymmetric plate girder webs with and without a longitudinal stiffener is presented. The results of a finite element analysis were used to develop a buckling coefficient for longitudinally stiffened webs which takes into account the depth of the web in compression and the vertical location of the stiffener. The results are compared with the AASHTO Bridge Specifications and a design example is presented.
Formulas for Beams with Semi-rigid Connections
Authors: Kotlyar Nathan
Published: April 2024

This paper presents practical formulas for beams with semi-rigid connections of variable stiffness, and describes certain limitations for application of these formulas. Using the tables of formulas, the engineer is able to rapidly determine the effect of a partially restrained connection. A practical example illustrates the application of the formulas.
Design of Tension Circular Flange Joints in Tubular Structures
Authors: Cao Junjie , Packer Jeffery A.
Published: April 2024

As the use of circular steel tubes in different structures has increased dramatically in recent years the connections between tubes have become very important. One of the most important and common methods of making connections, especially field connections, in tubular structures is with bolted circular flanges. The design of such a joint under an overall axial tension force requires the determination of flange dimensions and the number and arrangement of bolts. Based on previous theoretical research work and tests on circular flange joints in tubular structures, a new design method for these joints is proposed. Design charts, which are in accordance with the AISC LRFD design specification, have been produced and can be used to decide flange thickness and number of bolts for a joint very easily. These design charts are produced for one tube grade and one flange grade but can be modified for various grades of tube and flange plate materials, both A325 and A490 bolts, and various levels of tension load applied to the connection. It has been shown that the method is accurate, reliable and easy to use.
The Dogbone: Back to the Future
Authors: Plumier Andre
Published: April 2024

The weakening of specific sections of a structure in order to change them into reliable energy dissipative zones in case of an earthquake is an idea which was developed in principle in the 1980s by the author of the present paper. During a research project sponsored by the Luxembourg based steel producer ARBED and the European Union, the idea was tested and validated as concerns its contribution to ductility. Because weakening a structure, even locally, might have negative influences, other analyses were also performed during the same research and later on by David (1990). At that time, ARBED filed a patent on the reduced beam section (RBS) or "dogbone" concept, but, after the Northridge earthquake, waived any licensing fees and claims. This certainly encourages the development of this technique. Research efforts are now being made in many places in the United States to define the best applicability conditions for dogbones, in particular their geometry. In a recent paper in this Journal, Iwankiw and Carter (1996) presented test results based on this idea, whose time has come. In order to further its applications, existing European data, some of which were published by the Commission of the European Community (1992) in the report on the research mentioned above, some published in conference proceedings by Plumier (1990), some unpublished, are presented here.
Optimization of Large Space Frame Steel Structures
Authors: Soegiarso R. , Adeli H.
Published: April 2024

Optimization of large space frame steel structures subjected to realistic code-specified stress, displacement, and buckling constraints is investigated. The basis of design is the American Institute of Steel Construction (AISC) Allowable Stress Design (ASD) specifications. The types of structures considered are space moment resisting frames with and without bracings. The structures are subjected to wind loadings according to the Uniform Building Code (UBC) in addition to dead and live loads. The parallel-vector algorithm developed in this research is applied to three highrise building structures ranging in size from a 20-story structure with 1,920 members to a 60-story structure with 5,760 members, and its parallel processing and vectorization performance is evaluated. For the largest structure, speedups of 6.4 and 17.8 are achieved due to parallel processing (using eight processors) and vectorization, respectively. When vectorization is combined with parallel processing a very significant speedup of 97.1 is achieved.
Calculation of the Plastic Section Modulus Using the Computer
Authors: Bauer Dominique Bernard
Published: April 2024

A simple spreadsheet is presented which calculates the plastic section modulus of structural members. The method consists in dividing the cross section into rectangles and arranging all calculations conveniently into a spreadsheet program. The basic algorithm and the required spreadsheet formulas are given as well as a numerical example.
The Behavior and Load-Carrying Capacity of Unstiffened Seated Beam Connections
Authors: Chen Wai-Fah , Bowman Mark D. , Yang W.H.
Published: April 2024

Unstiffened seated-beam connections are often used to connect a beam to a column. For many years this connection was designed by using tabular methods in the AISC Design Manuals, including the most recent LRFD Manual. The manual tables are generated based on the required bearing length method developed in 1940s. This paper investigates the validity of this method by examining the formulations of the model and analyzing the connection behavior. The interactions between connection components are discussed and more rational and accurate models are developed for connections consisting of a flexible angle and a stiff beam. Through comparison of various results, the current LRFD procedures are assessed and practical implications of this research are summarized.
The Restraint Girder System- Local Web Buckling Behavior and Design Considerations
Authors: Wexler Neil , Bao Lin Feng
Published: April 2024

The Restraint Girder System (RGS) was previously presented as a new design option for composite girders. RGS is a composite steel and concrete girder, made continuous with rigid or semi-rigid connections. The RGS design provides beneficial cost, depth and deflection results, and is easy to construct. Various parts and components of the Restraint Girder System were previously studied by the writer, Van Dalen, Leon, Johnson, Kemp and others. Local web buckling was studied by Kemp. This paper presents an analysis for web buckling considerations when US steel shapes are designed with RGS, provides a definitive classification for all US shapes and provides recommendations to be included in a future RGS addition to the Code. This paper presents the mathematical analysis for web buckling considerations, indicates how U. S. steel sections with RGS are rated for local web buckling and provides recommended options for ductility.
Critique: Strengthening of Existing Composite Beams Using LRFD Procedures
Authors: Wanant Sompandh
Published: April 2024

Critique
Discussion: The Behavior and Load-Carrying Capacity of Unstiffened Seated Beam Connections
Authors: Carter C.J. , Thornton W.A. , Murray T.M.
Published: April 2024

Discussion
Web Shear Strength of Flexural Members
Authors: Segui William T.
Published: April 2024

The shear strength of webs of flexural members is given in the AISC LRFD Specification (AISC 1993) in three separate places: Chapter F, Beams and Other Flexural Members; Appendix F; and Appendix G, Plate Girders. Chapter F covers only unstiffened webs with no tension-field action, Appendix F covers both stiffened and unstiffened webs with no tension-field action, and Appendix G covers stiffened and unstiffened webs, with or without tension-field action. A total of nine equations are given for Vn the nominal shear strength. It will be shown here that with a slight modification of the variable Cv (the ratio of critical web shear buckling stress to shear yield stress), these nine equations can be reduced to two equations that cover all conditions—stiffened or unstiffened webs, tension field or no tension field.
Errata: Discussion of A Summary of Changes and Derivation of LRFD Bolt Design Provisions
Authors: Biren Joseph
Published: April 2024

Errata
Errata: Practical Application of Energy Methods to Structural Stability Problems
Authors: Nair R. Shankar
Published: April 2024

Errata
Optimal Stiffness Design to Limit Static and Dynamic Wind Responses of Tall Steel Buildings
Authors: Chan Chun-Man
Published: April 2024

With the continuing trend of constructing taller and slender buildings with higher strength materials and lighter structural systems, modern tall steel buildings are wind sensitive structures that are prone to serviceability problems. Two important serviceability limit states for tall building design are lateral deformations and motion perceptions under wind loads. Excessive lateral deformations have been found to cause windows to rack, non-structural partitions to crack and cladding to collapse. Exorbitant oscillations induced by turbulent wind have been known to cause occupant discomfort and even shatter windows.1,2 The functions of tall buildings may be disrupted due to inadequate design for serviceability. Indeed, the design of tall slender buildings is generally governed by serviceability stiffness criteria rather than by ultimate strength safety requirements. An automatic resizing technique for the optimal stiffness design of tall steel building frameworks is presented in this paper.
Closure: Improved Shear Strength of Webs Designed in Accordance with the LRFD Specification
Authors: Bradford Mark A.
Published: April 2024

Closure
Discussion: Improved Shear Strength of Webs Designed in Accordance with the LRFD Specification
Authors: Ellifritt Duane S.
Published: April 2024

Discussion
The Effects of Over-Compressing ASTM F959 Direct Tension Indicators on A325 Bolts Used in Shear Connections
Authors: Schmeckpeper Edwin R. , Nielsen Richard J. , Gentry Guy
Published: April 2024

Direct tension indicators (DTIs) are one alternative method that is commonly used to verify that high-strength bolts have been properly tensioned during installation. This research attempts to resolve question concerning the use of bolts which may have been over tensioned, as evidenced by DTIs which were completely flattened to zero DTI gaps. A variety of bolt and DTI combinations were tested to determine how far the nuts could rotate before the bolt fractured. Sets of bolts and buts could rotate before the bolt fractured. Sets of bolts and nuts with DTIs were then tensioned to the point of incipient failure and tested in single and double shear. These tests indicated there was no significant decrease in the single and double shear strengths of these over-tensioned bolts. In addition, a series of tests compared the performance of the DTIs manufactured per ASTM F959-90 to those manufactured per ASTM F959-96. These tests indicated that the F959-96 DTIs exhibit less variability and indicate higher preloads at the specified DTI gaps compared to those manufactured to F959-90
Preface to the North American Design Comparisons
Authors: Gilmor Michael I. , Iwankiw Nestor R. , Martinez-Romero Enrique
Published: April 2024

Preface to the North American Design Comparisons
Design Criteria for Stiffened Seated Connections to Column Webs
Authors: Ellifritt Duane S. , Sputo Thomas
Published: April 2024

In multistory braced frames, simple, or Type PR connections of beams to columns are often made using beam seats. These may be made with heavy angles or, if loads are large, a stiffened seat may be used. The stiffened seat is usually made by welding two plates in the form of a tee, as shown in Figure 1. A seated connection has an advantage over a framed connection in that it can permit larger fabrication and erection tolerances, requires only two bolts, and provides a stable erection platform for the beam before any bolts are installed. When attached to a column flange, the capacity of the seat is calculated by checking the fillet welds in combined shear and tension. There are tables in Volume II of the AISC Manual (AISC, 1995) that already have these values worked out for various seat and stiffener sizes. Because of the column flange stiffness, the seat will rotate very little under load, usually less than the end of the beam which rests on it.
Gusset Plate Connection to Round HSS Tension Members
Authors: Cheng J.J.R. , Kulak Goeffrey L.
Published: April 2024

An experimental program and associated numerical analysis were undertaken to study the shear lag effect in round hollow structural section (HSS) tension members that are welded to gusset plates. The connection is made by slotting the tube longitudinally, inserting the gusset plate, and then placing longitudinal fillet welds at the tube-to-gusset interface. Transverse welds at the junction of the slot and the gusset plate may or may not be present. A total of nine specimens with three different tube sizes and various weld lengths were tested in the program. The majority of the specimens failed by fracture of the tube somewhere between the two gusset plates, and there was considerable ductility prior to fracture. Numerical analyses of the connections were carried out using an elasto-plastic model and measured material properties. Based on the tests and the numerical analyses, it is concluded that shear lag does not significantly affect the ultimate strength of the slotted tube connection, even with a weld length as little as 80 percent of the distance between the welds. The studies showed that the restraint provided by the gusset plate at the slotted end effectively increases the load-carrying capacity of the tube as compared to the unrestrained portion of the member. In the numerical analysis, fracture is assumed to have occurred when the equivalent plastic strain reaches a critical value. The test results are discussed in light of the requirements in the American Institute of Steel Construction (AISC) Specification for Design of Steel Hollow Structural Sections (AISC, 1997).
Errata: Panel Zone Yielding in Steel Moment Connections
Authors: El-Tawil Sherif
Published: April 2024

Errata
Design of Mill Building Columns Using Notional Loads
Authors: Schmidt Jon A.
Published: April 2024

Structural engineers have long recognized that mill building columns constitute a unique design situation. These columns typically support both the roof of the building at the top and one or more crane rails at an intermediate elevation. They accomplish this by taking the form of one of four common configurations (Fisher, 1993): a uniform column with a cantilevered bracket, a stepped column, separate laced columns, or separate battened columns (Figure 1). The last three options involve the use of a stronger and stiffer column section below the crane rail elevation by providing a larger section or a combination of two sections tied together for composite action. The presence of applied crane loads and, often, a transition of section properties at a point within the in-plane unbraced length of the overall column presents special challenges to the designer attempting to assess the member's strength and stability. Traditionally, determination of the load capacity of a steel column requires the calculation of an effective length factor, K. This value, when multiplied by the column's actual unbraced length, estimates the length of an equivalent pin-ended column with the same buckling load as the actual column. To be reasonably accurate, the effective length factor must account for various influences on the column's behavior, including initial material and geometrical imperfections, inelasticity, end restraint characteristics, and both horizontal and vertical interaction among the columns in the frame being analyzed. Over the years, engineers have developed several special procedures for establishing effective length factors for mill building columns that reflect their unique loading and geometry.
Design of Skewed Connections
Authors: Kloiber Larry , Thornton William A.
Published: April 2024

Skewed connections result when members frame to each other at an angle other than 90 degrees. This paper provides some guidance in the choice of connection, based on safety and economy, and discusses some of the design considerations required for these connections. The standard connection details assume that the members being connected frame at right angles to each other. In most structures there will be some members, which do not meet at right angles. These are referred to as skewed connections. They require special design considerations to provide for safety while providing an economic structure
Design Considerations for W-Shape Flexural Members Built-Up from Plates
Authors: Drake Richard M. , Bankes Michael E.
Published: April 2024

It is common practice in some areas of the world to buildup or fabricate W-shapes from plate as alternates to rolled W-shapes. It is also possible that in order to meet project delivery schedules, a fabricator may request approval from the engineer-of-record to substitute a built-up W-shape for a temporarily unavailable rolled W-shape. In either case, it would be practicable if the engineer-of-record can select his Wshape members using the AISC Manual (AISC, 1994) and LRFD Specification (AISC, 1999) and companion design aids. This paper addresses design and/or fabrication issues for the practice and attempts to arrive at "rules" to allow safe and timely application.
The Effects of a Severe Fire on the Steel Frame of an Office Building
Authors: Dexter Robert J. , Lu Le-Wu
Published: April 2024

This paper discusses the effects a severe fire had on a steel high-rise frame. The damage to this frame was no worse than in other fire-damaged steel-framed buildings such as the Alexis Nihon hotel in Montreal and the Broadgate in London. The yield strengths of the columns were not significantly decreased. There were locked-in residual moments and forces. However pushover analyses of simple frames with and without residual moments show that the stability and lateral load carrying capacity of the frames were unaffected by residual moments, as would be expected from the principles of plastic analysis. The steel frame and floor system of this building could have been reinstated relatively quickly, as has been done in comparable fire-damaged steel-framed high-rises.
Effect of Compound Buckling on Compression Strength of Built-up Members
Authors: Duan Lian , Reno Mark , Uang Chia-Ming
Published: April 2024

Design engineers frequently use built-up members for steel building and bridge construction for economical reasons. The first issue is the shearing effect. For laced or battened members, the shear deformation produced by laces or battens would reduce the buckling capacity. Two types of built-up members are commonly used for steel construction. Laced or battened members with widely spaced flange components fall in the first type, and closely spaced steel shapes interconnected at intervals by welds or connectors form the second type. The compressive strength of both types of members is affected by the shearing effect. For the first type, the shearing effect results from the deformation of flanges and laces, while for the second type the effect is caused by the shearing of intermediate connectors. The LRFD Specification (AISC, 1999) considers the shearing effect of the second type, but not the first type.
A Technical Note: Comparison of Design Specifications for Design of Pipe and Round HSS Pedestrian Guardrail Systems
Authors: Sputo Thomas
Published: April 2024

A guardrail system is a building component located near the open side of an elevated surface for the purpose of minimizing the possibility of a fall from the elevated surface by people, equipment, or material (ASCE, 2000). A typical pedestrian guardrail is illustrated in Figure 1. While architects usually handle the specification of guardrail systems for most buildings, the structural design of these systems is generally within the area of expertise of the project structural engineer. Often, the project architect will only provide general guidance on the configuration of the guardrails, leaving the actual structural design to the fabricator. This paper is based on years of experience gained by the author as a consultant to several structural steel and miscellaneous metals fabricators designing guardrail systems. For most situations, the AISC-LRFD specification provides for greater post spacings than any of the other design specifications considered, creating designs which are more economical and perhaps more visually appealing.
Ultimate Strength Prying Models for Bolted T-stub Connections
Authors: Swanson James A.
Published: April 2024

Several recognized prying models are discussed and evaluated using experimental data collected during 21 component tests conducted as part of a SAC investigation at the Georgia Institute of Technology as a basis. Four existing prying models are considered in addition to the model that appears in the European design specification. A modification of an existing design model is proposed.
Composite Steel Joists
Authors: Samuelson David
Published: April 2024

Composite steel construction has been recognized for a number of years as one of the most economical systems for constructing building floors. Three options have evolved over the years to meet the requirements for building height limitations and the need to run complex heating, ventilating, electrical, and communication systems: (1) Composite wide flange beams with web openings; (2) Stub girders; and (3) Open web steel joists and joist girders. This paper focuses on the advantages associated with composite open web steel joists, development and testing of open web steel joists, behavior of welded shear studs observed while testing composite joists, case histories of projects using composite joists, unique vibration considerations associated with joist floors, and current status of composite joist specification development.
Discussion: Thermal Prestressing of Structural Steel
Authors: Barnoff Robert M.
Published: April 2024

Discussion
Testing of a Model Curved Steel Girder Bridge
Authors: Clarke C. Bernard
Published: April 2024

Tests of three 1/8-scale curved girder bridge models are being conducted in the Civil Engineering Department at the University of Rhode Island at Kingston, with the purpose of confirming analytical solutions. This is a report on one of these tests, a three-girder, two span model of a 160 ft long prototype bridge. The model actually simulates a highway ramp for a typical city interchange. Our objective as stated in the beginning was to try to prove that Professor Lavelles analysis is accurate. Results from testing this three-girder model bridge indicates that the analysis is conservative and accurate within limits tolerable to design.
Evaluation of Applicability of Typical Column Design Equations to Steel H-Piles Supporting Integral Abutments
Authors: Ingram Earl E. , Burdette Edwin G. , Goodpasture David W. , Deatherage J. Harold
Published: April 2024

The use of integral abutment bridges with abutments supported on steel H-piles has become common practice in a number of states. These H-piles are subjected to various combinations of axial load and bending moment as the bridge undergoes temperature change. One commonly used approach to the design of these H-piles is, first, to perform an analysis to estimate the distance between inflection points on a pile and, second, to apply the AASHTO or AISC column design equations to the design of the pile. This approach neglects any lateral support provided by the soil between inflection points.Tests were performed to determine the ability of piles to support combinations of axial load and bending moment that fell outside the limits of interaction diagrams based on AASHTO and AISC column design equations. Combinations of axial load and moment were measured which correspond to the plastic limit capacity of a pile cross-section with no length effects considered. The test results clearly demonstrated the inapplicability of the AASHTO and AISC column design equations, which consider length effects, to steel H-piles embedded in soil. Combinations of axial load and moment corresponding to the plastic limit capacity of a pile cross-section can more reasonably be used to evaluate the capacity of a pile.
MTR Survey of Plate Material Used in Structural Fabrication
Authors: Brockenbrough Roger L.
Published: April 2024

A statistical survey was made for a broad sample of mill test reports (MTR) of plate grades typically used in building construction including A36, A572, A588, A852, and A514 steels. Tensile properties, impact properties, and chemical compositions were analyzed. The tensile statistics agreed with assumptions made in the development of the AISC Load and Resistance Factor Design Specification for Structural Steel Buildings (LRFD Specification) (AISC, 1999). The yield-tensile ratios varied from 0.61 to 0.94, following the typical trend of increasing yield-tensile ratio with increasing strength level. The mean CVN values at 70ºF were generally over 100 ft-lbs. for all the steels, which is attributable to the fact that the toughness data were generally reported for product with specified minimum values. The minimum CVN values at 70ºF all met or exceeded the 20 ft-lbs. value specified by AISC for plate material over 2 in. thick used for built-up cross sections spliced with complete-joint-penetration groove welds and subjected to tension. The statistical analysis of composition generally indicated good weldability, particularly for A36 and A572 Grade 50.
Achieving a Stable Inelastic Seismic Response for Multi-Story Concentrically Braced Steel Frames
Authors: Tremblay Robert
Published: April 2024

Recent seismic design provisions (CSA, 2001; AISC, 2002) for concentrically braced steel frames (CBFs) aim at dissipating seismic input energy through inelastic deformations in the bracing members. These deformations include tension yielding of the braces as well as plastic hinge rotation that develops upon buckling of the braces in compression and subsequent straightening of the braces when pulled in tension in the next loading cycle. Over the years, researchers have gained a good understanding of the hysteretic response of steel braces (Jain, Goel, and Hanson, 1980; Popov and Black, 1981; Astaneh-Asl and Goel, 1984; Astaneh-Asl, Goel, and Hanson, 1985) and detailing requirements such as maximum b/t and KL/r ratios are now prescribed in codes to achieve ductile brace response. Capacity design rules have also been introduced in codes to prevent premature failure of the brace connections and ensure that the response of the beams and columns will remain essentially elastic (Tremblay, 2001). Concentrically braced steel frames are particularly vulnerable to dynamic instability under seismic ground motions compared to other lateral load resisting systems due to the inherent poor hysteretic response of the diagonal bracing members and the tendency to develop story mechanisms in multi-story applications. The stability of CBFs responding in the nonlinear range to earthquake ground motions is a complex problem that depends on several parameters including the properties of the bracing members, the bracing configuration, the characteristics of the ground motions, the lateral resistance of the structure relative to the seismic demand and the amount of gravity loads supported by the structure. In multi-story frames, the potential for collapse by instability is also influenced by other parameters including the number of floors and the distribution of the lateral resistance over the building height. As of today, no simple method has been proposed for design purposes to adequately capture the combined effects of all these parameters.
Constrained Axial Buckling About Non-Principal Axes
Authors: Zvarick Albert G.
Published: April 2024

When certain structural members are used in axial compression, framing considerations dictate the orientation of the cross section about the member's longitudinal axis. When a second member is framed to the first, a constraint is imposed which forces the member to buckle about a non-principal axis. The author investigates axial buckling for this case, and formulates equations for the compound buckling of axial compression members. Formulas are derived using the differential equations of classical structural stability mechanics. For the initial case analyzed, where a member is continuously supported about a non-principal axis, the author discovered that the classical Euler buckling equation holds, but the radius of gyration is calculated about the respective nonprincipal axis. Due to coupling from the product of inertia, a moment is induced about the orthogonal non-principal axis.
Continuity Plate Detailing for Steel Moment-Resisting Connections
Authors: Hajjar Jerome F. , Dexter Robert J. , Ojard Sara D. , Ye Yanqun , Cotton Sean C.
Published: April 2024

The 1994 Northridge, California earthquake resulted in the fracture of complete-joint-penetration groove (CJP) welds connecting girder flanges to column flanges in steel moment-resisting connections in a number of steel frame structures ranging from one to 26 stories in height (FEMA, 2000a). These welds fractured due to a combination of reasons, including the weld material having low fracture toughness; the pre-Northridge connection geometry making the CJP welds more susceptible to high strain and stress conditions; and welding practices that resulted in inconsistent weld properties (FEMA, 2000a). As a result of these fractures, in the subsequent years there has been a tendency to be more conservative than necessary in the design and detailing of steel moment-resisting connections both in seismic and non-seismic zones within the United States. In particular, continuity plates and web doubler plates have often been specified when they are unnecessary and, when they are necessary, thicker plates have been specified than would be required according to the applicable specifications. In addition, the welds of the continuity plates to the column flanges have often been specified as being complete-joint-penetration groove welds, even though the use of more economical fillet welds may have sufficed. This paper has given the background of the local web yielding and local flange bending limit states and the conclusions of previous researchers regarding the behavior of continuity plates and the welds attaching them to columns. It has also summarized the results of nine pull-plate tests and corresponding finite-element analyses studying column-stiffening details. The preliminary conclusions from these tests are focused on monotonic loading applications and will be synthesized with future cyclic loading experiments, with implications for seismic design, in Lee and others (2002) and other ongoing research.
Discussion: Comparison of Design Specifications for Design of Pipe and Round HSS Pedestrian Guardrail Systems
Authors: Moore II William E.
Published: April 2024

Discussion
Discussion: Design Concepts for Jib Cranes
Authors: Hemstad Michael
Published: April 2024

Discussion
Elastic In-Plane Stiffness for a Circular Cut Reduced Beam Section (RBS)
Authors: Iwankiw Nestor R. , Mohammadi Jamshid
Published: April 2024

One newer moment connection that has been introduced and validated (prequalified) for use in high seismic areas is the so-called "dogbone"ť, or reduced beam section (RBS). The purpose of this paper is to briefly review the basic in-plane stiffness formulation for a prismatic beam, develop more rigorously the full non-prismatic, first-order elastic stiffness changes caused by the circular RBS, provide its simplified representation, and finally conclude with the general RBS stiffness effect suggestions for design. Other RBS seismic design and performance issues of this efficient and popular detail will not be addressed, as they are already well covered in other available sources.
Structural Steel Detailing Practices--Good and Bad
Authors: Dobbie Hugh
Published: April 2024

This paper summarizes important concepts presented in the recent update of the AISC Detailing for Steel Construction manual. Specifically, the following topics are discussed: basic detailing conventions, project set-up and control, shop drawings and bills of material, detailing quality control and assurance, and electronic design and detailing. Recommended detailing practices are emphasized and contrasted with poor practices.
Errata: Design and Construction of Lifting Beams
Authors: Ricker David T.
Published: April 2024

Errata
Technical Note: Abrasive Waterjet Cutting Application
Authors: Higgins Christopher C. , Newell James D.
Published: April 2024

Abrasive waterjet cutting is a relatively little used technique for fabrication of structural steel components. The technique may permit economical fabrication of earthquake resistant structural steel members such as core elements of buckling-restrained braces. Abrasive waterjet cutting was used to fabricate yielding core elements for a new type of buckling-restrained brace. A 50,000 psi (344.7 MPa) waterjet and garnet abrasive cutting stream was computer numerically controlled to cut dog-bone and perforated yielding core configurations in 3/4 in. (19.05 mm) and 1-1/4 in. (31.75 mm) A36 steel bar stock. Abrasive waterjet cutting is a cold process and does not produce the heat affected zone associated with oxyfuel or plasma cutting. Tension coupon testing of a small number of samples of both traditionally machined and abrasive waterjet cut specimens indicated little change in the ultimate stress and only slightly reduced yield stress and total elongation for abrasive waterjet cut A36 steel coupons.
Confined Steel Brace for Earthquake Resistant Design
Authors: Higgins Christopher C. , Newell James D.
Published: April 2024

An experimental study of a passive energy dissipation tension-compression yielding brace or buckling-restrained brace has been conducted. The Confined Yielding Brace (CYB) consists of a steel yielding core confined within a tube filled with non-cohesive material. The external tube and confined non-cohesive material provide lateral stability to the core enabling the device to yield in compression as well as tension. This device is similar to the Unbonded Brace developed by Nippon Steel of Japan. Fourteen large-scale CYBs were tested to determine the effect of varied confining material, yielding core perforation blocking configurations, and displacement histories. Based on experimental results, Confined Yielding Braces produce relatively stable and symmetric hysteretic damping.
Recommended Effective Throat Sizes for Flare Groove Welds to HSS
Authors: Packer Jeffrey A. , Frater George S.
Published: April 2024

An experimental research project has been undertaken to investigate the geometric properties, and in particular the effective throat size, of flare bevel and flare-V partial joint penetration groove welds at the corners of Hollow Structural Sections (HSS). HSS-to-plate (flare bevel) and HSS-to-HSS (flare-V) single-pass welds were carefully performed to Welding Procedure Specifications agreed within a Project Oversight Committee, using ASTM A500 tubing, then cross-sectioned after inspection to produce 180 test welds. Parameters included three HSS sizes (with wall thicknesses ranging from 3/16 in. to 3/8 in.), four welding processes (FCAW-G, FCAW-S, GMAW and SMAW) and four welding positions (flat, horizontal, vertical and overhead). All weld cross-sections were polished and etched, then had their profiles digitally recorded and measured. An analysis of the resulting data has shown that the current pre-qualified effective throat sizes for these two weld types, in AWS D1.1/D1.1M:2004, can be made more liberal for most weld processes.
Flexible Moment Connections for Unbraced Frames Subject to Lateral Forces — A Return to Simplicity
Authors: Geschwindner Louis F. , Disque Robert O.
Published: April 2024

It seems that there has been confusion among structural engineers about the type of construction referred to in the AISC Load and Resistance Factor Design Specification for Structural Steel Buildings (AISC, 2000), since 1986, as Partially Restrained or PR. The general concept has been of interest to the authors for many years and has been the topic of several of their papers. The purpose of this paper is to reacquaint the profession with a longstanding and successfully applied approach to structural steel frame design, herein called "Flexible Moment Connections (FMC)," and to compare this approach to the Specification-defined PR approach. In addition, the goal is to show that although much has changed in the profession, including specifications and the tools for their application, FMC design remains an acceptable and economical approach for steel structures.
A Historical and Technical Overview of the Cb Coefficient in the AISC Specifications
Authors: Zoruba Sergio , Dekker Brian
Published: April 2024

Some fundamental, yet not well-understood aspects of the Cb coefficient are discussed. This paper also documents the technical basis for the Cb coefficient and discusses the historical changes to the Cb coefficient from the 1989 ASD Specification through the 1999 LRFD Specification. Answers are provided to the most frequently asked questions concerning the use and interpretation of the Cb expressions found in the AISC Specifications.
The Effects of Stress Singularity on Welded Gusset Plates Loaded in Tension
Authors: Hsiao J. Kent , Widjaja Suhendi , Schultz William , Wiemeler Steven
Published: April 2024

In spite of the extensive study of gusset plates under monotonic tension loading over the years, the stress singularity (unbounded stress) effect caused by the boundary condition at the corners of the fixed edges of the plates has seldom been considered by researchers and structural design engineers. Since the development of the tensioned stress concentration resulting in fracturing of gusset plates can be expedited by the stress singularity effect, the effects of stress singularity on steel gusset plates should not be neglected. The stress concentration of welded gusset plates caused by the stress singularity effect is investigated using the finite element method in this study. Numerical investigations of the interaction between the stress singularity effect on the gusset plates and the Whitmore effective section of the gusset plates are also conducted. Based on the investigation results, optimal configurations and modified Whitmore effective widths for gusset plates loaded in tension are presented and discussed. Later in this paper a practical design example is given which considers both the optimal configuration and the modified Whitmore effective section of the gusset plate.
Effects of Cope Geometry on the Strength and Behavior of Cellular and Castellated Beams
Authors: Hoffman R. M. , Dinehart D.W. , Gross S.P. , Yost J.R. , Hennessey J.M.
Published: April 2024

This paper reviews an experimental and analytical investigation of the effect of cope geometry ( distance) on the strength and failure behavior of non-composite, doubly symmetric, uniformly loaded open web expanded beams. Thirty-six (36) beams, eighteen (18) cellular (circular openings) and eighteen (18) castellated (hexagonal openings), of various cope geometries and depths, each instrumented to measure load, strain and displacement, were tested to failure. A linear elastic finite element (FE) analysis for service loading conditions and a nonlinear FE buckling analysis were performed in parallel with the experimental testing program. The experimentally validated models were then extended to uncoped and intermediately coped beam geometries to investigate the effect of cope geometry on beam capacity and failure mode. Through this study, it was found that failure loads for the beams exceeded calculated design loads (ASD) by a minimum factor of 1.8 regardless of cope size or beam type. Further, cellular beams experienced less percent capacity loss with increasing cope size than did castellated beams.
Cyclic Behavior of Steel Moment-Resisting Connections Reinforced by Alternative Column Stiffener Details II
Authors: Lee Daeyong , Cotton Sean C. , Hajjar Jerome F. , Dexter Robert J. , Ye Yanqun
Published: April 2024

A study has been conducted to reassess the current AISC seismic panel zone design criteria for the Welded Unreinforced Flange-Welded Web (WUF-W) steel moment-resisting connections and to investigate acceptable minimum seismic panel zone design criteria for moment-resisting connections. Five full-scale WUF-W cruciform specimens were tested in this research, coupled with corroborating nonlinear finite element analysis. All had relatively weak panel zones designed to cause large localized strain concentrations in the girder flange-to-column flange connection region and to exceed the panel zone shear deformation of the 4gy (in other words, four times the panel zone shear yield strain, gy). This paper presents the cyclic panel zone behavior of the WUF-W cruciform specimens and an assessment of the current AISC seismic panel zone design criteria for these connections. Two possible modifications for seismic panel zone design criteria are then proposed and verified against these tests as well as experiments from the literature. One equation provides a more accurate assessment of panel zone nominal strength for steel moment-resisting connections, and the second equation provides a panel zone required strength equation that targets permitting up to 8gy panel zone shear deformation for WUF-W and similar connections.
Discussion: Beam-Column Base Plate Design—LRFD Method
Authors: Doyle James M. , Fisher James M.
Published: April 2024

Discussion
Development of Fabrication Guidelines for Cold Bending of Plates
Authors: Brockenbrough Roger L.
Published: April 2024

To avoid plate cracking during cold bending, it is necessary to use a suitable minimum inside bend radius, which typically varies with plate thickness and grade. However, because of the addition of new plate grades over the years, it was felt that the limits that had been given in ASTM A6 until recently, had not been developed on a consistent basis. Also, those limits were intended for material acceptance purposes using small specimen tests, and did not directly reflect fabrication limits. Therefore, a program was initiated by AISI about 1996 to develop rational limits directly applicable to plate fabrication. In the initial study, conducted by Concurrent Technologies Corporation, small specimens of various grades and thicknesses were cold formed using different bend radii and evaluated. In subsequent work, the present study was made to review that information, review historical forming limits, and develop a rational set of consistent limits for fabrication guidelines. It was concluded that radius-to-thickness limits from idealized bending limit diagrams developed from specimen tests could be used to establish fabrication limits, if appropriate allowances were made for conditions in fabrication that differ from those in the tests. This includes adjustments to account for plate properties that approach minimum specified values rather than the typical properties of the test material, thicknesses greater than those tested, and edge or surface imperfections that may be present in typical fabrication. After making such adjustments, a table of suggested limits was developed and subsequently adopted in ASTM A6. The adopted values were generally more liberal (allowed tighter bends) than those that had been given in the AISC Manual, thus providing greater flexibility in fabrication in most cases.
Bracing of Beams, Trusses, and Joist Girders Using Open Web Steel Joists
Authors: Fisher James M.
Published: April 2024

Designers typically use joists as a part of the lateral bracing for the compression flange of beams, or for the lateral bracing of the top chord of trusses and joist girders. Joists serve as the connection to the primary members to deliver the brace force to a diaphragm or horizontal bracing system. The attachment of the joist seat to the primary member is an important element of the bracing system. Traditionally joist seats have been attached to primary members (beams, trusses, and joist girders) by welding. The OSHA Steel Erection Standard, Part 1926.757 - Open Web Steel Joists states: (i) Except for steel joists that have been pre-assembled into panels, connections of individual steel joists to steel structures in bays of 40 ft (12.2 m) or more shall be fabricated to allow for field bolting during erection; (ii) These connections shall be field-bolted unless constructability does not allow. The purpose of this paper is to discuss possible alternatives to welding the joists to the primary members in order to provide bracing to the primary members.