bluuebunny/crossref_metadata_2025 huggingface dataset:
Small Scale Models for Steel Frameworks
Authors: Litle William A.
Published: April 2024

The analysis and design of steel structures has become increasingly sophisticated and efficient in the last decade. For conventional structures, present methods of analysis can be employed with confidence with the proportioning of members based upon some prescribed criteria, such as building and bridge construction codes. When these methods can be employed, there can be no economic justification for a model study of a structure. Some aspects of both member and whole structure behavior, however, are still not well understood for these conventional structures and as new design criteria are developed for these situations, testing programs will be required. For unconventional structures, mathematical analyses that appropriately account for the complex geometries and behavior may not be available. It is in these areas, the development of design criteria for conventional structures and the study of unconventional structures, that model analysis can be useful. The use of experimental methods has already been demonstrated in tests carried out on full scale sections atLehigh University and other schools. These tests have effectively contributed to the incorporation of plastic design into building codes. On the other hand, full scale tests have a number of limitations. To date tests have been restricted to simple members and simple one, two or three story plane frames. While more complex structures, in many cases, would have masked the phenomenon under study there are situations where tests on larger or more complete structures would have been appropriate. Even in those situations where full scale study is feasible, the same total investment in small scale study would often permit a more comprehensive investigation. The purpose of this paper is to present the results of the first phase of a study aimed at establishing a reliable small scale ultimate strength modeling technique for wide-flange steel frameworks.
Discussion: Design of Bolts or Rivets Subject to Combined Shear and Tension
Authors: Bertwell W.
Published: April 2024

Discussion
Design Optimization Study of a Three-Span Continuous Bridge Using HPS70W
Authors: Clingenpeel Beth F. , Barth Karl E.
Published: April 2024

Since its introduction to the bridge market in 1996, High Performance Steel (HPS) has been successfully implemented in a wide range of bridge projects by several state transportation departments. Examples of which include the Snyder South Bridge in Nebraska that was initially designed using AASHTO M270 Grade 50 weathering steel. The Nebraska Department of Roads opted to use HPS70W in place of the Grade 50 weathering steel without performing any redesign. This was done to provide information on welding and fabrication issues with HPS70W (Wasserman, Azizinamini, Pate and Greer, 1998). Also, in 1996, the Tennessee Department of Transportation (TDOT) partnered with FHWA through the Innovative Bridge Research and Construction Program to use HPS70W in a bridge project. The TDOT was in the process of designing a two-span continuous bridge, with span lengths of 236 ft 6 in., located on Tennessee State Route 53 over Martin Creek (FHWA, 1998). The bridge has a roadway width of 28 ft on three I-girders spaced at 10-ft 6-in. The superstructure was redesigned utilizing HPS70W for the girders and Grade 50W steel for the stiffeners, cross-frames, and other miscellaneous steel. The designs were performed using the 1994 AASHTO LRFD Bridge Design Specifications. These bridges are reported to have cost savings on the order of 10 percent through the inclusion of HPS70W in their superstructures. This paper presents a cost analysis of a fixed three-span bridge incorporating various material and girder configurations. An optimized parametric design study was conducted by varying key superstructure design variables. Girders are optimized in this study based on least weight for a fixed span-to-depth ratio.
Errata: A Practical Look at Frame Analysis, Stability and Leaning Columns
Authors: Geschwindner Louis F.
Published: April 2024

Errata
Effect of Straightening Method on the Cyclic Behavior of k-Area in Steel Rolled Shapes
Authors: Chi Brandon , Uang Chia-Ming
Published: April 2024

Test results from a study investigating the effect of rotary-straightening on the cyclic behavior of k-area in rolled column shapes are presented in this paper. A total of five full-scale steel moment connections were tested. The first three specimens did not use continuity plates and a doubler plate; the only variable was the method of straightening of the columns (rotary-straightened, gag-straightened, and non-straightened). To increase the potential for fracture, a 1-in. diameter hole was drilled in the k-area of the column at the bottom flange level of the beam. Continuity plates and a doubler plate were used for the last two specimens - one with a rotary-straightened column and another one with a non-straightened column. The first three specimens all failed by fracture of the column flange outside the panel zone at large drift levels. No clear pattern indicating that rotary-straightening induced fracture was observed. Brittle fracture, which initiated from the beam web weld access hole, occurred at 6 percent drift for the last two specimens. Although this study did not reveal adverse effects created by rotary-straightening, it is prudent to avoid welding in the k area.
Plate Girders with Corrugated Steel Webs
Authors: Sayed-Ahmed Ezzeldine Yazeed
Published: April 2024

Girders with corrugated steel webs represent a new innovative system which has emerged in the past decade, especially for short span bridges. The new system combines the usage of corrugated steel plates as webs and either steel or reinforced/prestressed concrete slabs as flanges. The flanges are assumed to provide the flexural strength of the girder with no contribution from the corrugated web, which is assumed to provide the entire shear capacity of the girder. The corrugated web is thus, subjected to an "almost" pure shear stress state. Failure of a corrugated steel web plate may occur by the classical steel yielding of the web under a pure shear stress state. It may also occur by web buckling due to either local instability of any "panel" between two folds or overall instability of the web over two or more panels. An interactive failure mode between these different failure criteria represents another possibility of failure. In this paper, the shear behavior of corrugated steel webs is explicitly investigated focusing on the different failure modes which affect the web design. A closed form solution (interaction equation) that considers local buckling, overall buckling and steel yielding of the web is presented. Numerical analyses based on the finite element technique are performed to investigate the buckling modes of the corrugated web and to verify the validity of the proposed interaction equation. The effect of different geometric parameters on the failure mode of the corrugated web is inspected using the proposed interaction equation. A nonlinear finite element model is then used to investigate the post-buckling strength of girders with corrugated steel webs.
Errata: Structural Steel Detailing Practices--Good and Bad
Authors: Dobbie Hugh
Published: April 2024

Errata
Yielding Limit State of Tee Stems in Flexural Compression
Authors: Earls C.J. , Volle L.E.
Published: April 2024

The present paper outlines the results from a parametric study involving the finite element modeling of tee beams subjected to a constant moment loading resulting in stem compression and flange tension. The parameters varied as part of the study include: the flange width-to-cross-sectional depth ratio, bf/d; the unbraced length-to-cross-sectional depth ratio, Lb / d; the ratio of stem depth to stem thickness, h / tw; and the ratio of flange width to flange thickness, bf / 2tf. The present discussion focuses on how these parameters impact WT ultimate capacity and flexural ductility. Compactness limits for tee stems are subsequently proposed: currently such compactness limits are not prescribed by AISC for WT stems.
Closure: Updating Standard Shape Material Properties Database for Design and Reliability
Authors: Bartlett F. Michael , Dexter Robert J. , Graeser Mark D. , Jelinek Jason J. , Schmidt Bradley J. , Galambos Theodore V.
Published: April 2024

Closure
Discussion: Updating Standard Shape Material Properties Database for Design and Reliability
Authors: Bennett Richard M.
Published: April 2024

Discussion
Current Steel Structures Research No. 02
Authors: Bjorhovde Reidar
Published: April 2024

Current Steel Structures Research
On Moment Capacity and Flexural Ductility in Doubly Symmetric Web-Tapered I-Girders
Authors: Miller B.S. , Earls C.J.
Published: April 2024

The present paper summarizes the results of a finite element based parametric study aimed at quantifying the response of web-tapered I-girders loaded to failure. The geometry of the tapered beams considered is of realistic dimensions vis-Ã -vis normally encountered rafter sections used in metal buildings manufactured in the U.S. In addition, a comparison of the observed girder response, and the response predicted using the web-tapered flexural provisions from Appendix F in the LRFD Specification (AISC, 1999) is undertaken. The validity of the finite element modeling techniques employed herein is demonstrated using the results from experimental tests available in the literature.
Cyclic Behavior of Buckling Restrained Braces for Ductile End Cross Frames
Authors: Carden Lyle P. , Itani Ahmad M. , Buckle Ian G.
Published: April 2024

Ductile end cross frames (ductile end diaphragms) in bridge superstructures have been studied in the past as a potential mechanism for reducing transverse seismic shear in steel plate girder bridges. In this paper, the cyclic inelastic behavior of buckling restrained braces is studied for potential use in these end cross frames. It is shown that the buckling restrained braces exhibit excellent hysteretic behavior with similar properties in tension and compression. The tension yield force of the braces was measured to within 12% of predicted. The maximum force due to strain and cyclic hardening, at a strain of 2%, was typically 35% greater than the expected yield force, and increased by a further 15% or more, during dynamic loading. The maximum compression force was typically 10 to 15% greater than the tension force. When subjected to different loading histories it was found that large amplitude cycles at the beginning of the loading history followed by smaller cycles, and also dynamic loading, reduced the cumulative plastic strain capacity in the braces compared to reverse static loading with increasing amplitude. The area of the hysteresis loops from the braces is typically around 80% of the circumscribing rectangular area and increased as strains increased, unlike the degradation seen in the performance of other types of concentric braces after buckling, indicating efficient energy dissipation. The response of the braces can be approximately modeled with a bi-linear representation to capture the maximum forces, displacements and energy dissipation in the braces. It is recommended that a maximum brace strain of 2.0% be used for design of these buckling restrained braces to be used in ductile end cross frames. At this design strain the calculated cumulative displacement demand following a maximum considered earthquake is less than the displacement capacity of the braces.
Reliability of the Member Stability Criteria in the 2005 AISC Specification
Authors: Galambos Theodore V.
Published: April 2024

The notional reliability of steel beams, columns and beam-columns designed according to the 2005 AISC Specification for Structural Steel Buildings is determined by using first-order or second-order reliability methods (FORM or SORM). The reliability index beta is evaluated for contemporary material properties and new evaluations of experimental strength data. It is concluded that the notional reliability of the new specification is essentially identical to the level inherent in the first Load and Resistance Factor (LRFD) Specification of 1986.
The 2005 AISC Seismic Provisions for Structural Steel Buildings
Authors: Malley James O.
Published: April 2024

The American Institute of Steel Construction (AISC) standard, Seismic Provisions for Structural Steel Buildings, is the reference document for seismic design of steel structures throughout the United States. The 2003 International Building Code (IBC) incorporated these provisions by reference, and the 2002 National Fire Protection Association (NFPA) 5000 Building Code also followed this approach. Since their 1997 publication, the AISC Seismic Provisions have been updated on a regular basis in order to incorporate new developments from post-Northridge earthquake research on moment frames and other work in this area. The latest revision culminated with the publication of a completely new set of provisions in 2005 that is in the same unified format as the main AISC design specification. In addition, this edition makes reference to a new AISC standard for the pre-qualification of seismic moment connections that was also completed in 2005. Coordinated efforts between AISC and the Building Seismic Safety Council (BSSC) are intended to continue the process of keeping the seismic design provisions for structural steel buildings as current as possible. Efforts to coordinate with Canadian standards are also underway. This presentation will summarize the changes incorporated into the 2005 AISC Seismic Provisions and the use of the new moment connection pre-qualification standard. It will also speculate on future modifications and additions to the U.S. seismic design provisions for structural steel buildings.
Current Steel Structures Research No. 10
Authors: Bjorhovde Reidar
Published: April 2024

Current Steel Structures Research
Bending Strength of Steel Bracket and Splice Plates
Authors: Mohr Benjamin A. , Murray Thomas M.
Published: April 2024

The primary purpose of this study was to determine the ultimate behavior of bracket and splice plates. The study consisted of experimental testing and comparison of test results with various design methods. The experimental testing consisted of connecting two beams together with web splice plates to form a simple span, then loading the span symmetrically to induce pure moment at the location of the splice with the goal of achieving plate flexural rupture. This study indicates that design models used prior to the publication of the 13th Edition AISC Steel Construction Manual for determining bracket plate and web splice nominal moment strength are overly conservative.
Quantifying and Enhancing Robustness in Steel Structures: Part 1--Moment-Resisting Frames
Authors: Foley Christopher M. , Schneeman Carl , Barnes Kristine
Published: April 2024

The objective of this two-part manuscript is to provide information that can lead to: (a) better understanding of disproportionate collapse in structural steel framing systems; (b) improved understanding of secondary load paths that form within structural steel framing systems in the event of a localized failure; (c) development of minimum general structural integrity provisions for structural steel framing systems analogous to those present in ACI 318; (d) recommendations for minimum tie forces that can be used as the basis of indirect design methodologies for structural steel framing systems; (e) an understanding of the distribution of tensile forces within typical steel floor framing systems to facilitate compartmentalization damage or collapse; and (f) identification of simple and economical means with which to enhance the robustness in the typical structural steel framing system.
Cyclic Behavior and Seismic Design of Bolted Flange Plate Steel Moment Connections
Authors: Sato Atsushi , Newell James D. , Uang Chia-Ming
Published: April 2024

The AISC Connection Prequalification Review Panel (CPRP) is currently reviewing the bolted flange plate moment connection for inclusion in the next edition of the AISC Prequalified Connections for Special and Intermediate Steel Moment Frames for Seismic Applications. To expand the experimental database for prequalifying the bolted flange plate (BFP) moment connection for special moment frames, cyclic testing of three full-scale BFP steel moment connection specimens has been conducted. Beam sizes for these specimens (W30x108, W30x148, and W36x50) were larger than previously tested to extend the range of available experimental results. All three specimens performed well and met the Acceptance Criteria of the AISC Seismic Provisions. The specimens achieved an interstory drift angle of 0.06 radians before failure.
Technical Note: Optimum Flexural Design of Steel Members Utilizing Moment Gradient and Cb
Authors: Aminmansour Abbas
Published: April 2024

Flexural strength of members based on the limit state of lateral-torsional buckling is a function of the moment gradient of the unbraced length under consideration. Bending modification factor, Cb, accounts for the shape of the moment gradient within the unbraced length and allows for adjustment of the member flexural strength, possibly increasing it by a considerable amount. Therefore, neglecting the impact of Cb on member strength may lead to over-design. This paper discusses application of Cb to design of members subjected to bending including beams as well as members subjected to combined loading (compression and bending, tension and bending, or biaxial bending). Numerical examples are presented using both ASD and LRFD methods.
A Model Specification for Stability Design by Direct Analysis
Authors: Nair R. Shankar
Published: April 2024

This paper presents a model specification for stability design by direct analysis. It is based on the stability provisions of the 2005 AISC Specification, rewritten around the Direct Analysis Method alone. The material is presented in the language and format of the AISC Specification, including "User Notes" and the italicizing of terms listed in the glossary where they first appear in a section. The focus on a single method has offered the opportunity to expand some of the provisions beyond what is in the current AISC Specification, both to improve clarity and to address issues that have arisen from use of the document. Where this involved substantive changes, they are explained in an appendix to this paper (Appendix A). A second appendix (Appendix B) outlines the purpose or physical significance of each of the important steps in the Direct Analysis Method by showing the correlation of these steps to the basic requirements for design of structures for stability. The "traditional" Effective Length Method is included in the correlation to show how that method differs from the Direct Analysis Method. A third appendix (Appendix C) provides guidance to the user on the modeling of structures for the application of the Direct Analysis Method.
Experimental Evaluation of the Influence of Connection Typology on the Behavior of Steel Structures Under Fire
Authors: Santiago Aldina , Da Silva Luis S. , Real Paulo V. , Vaz Gilberto , Lopes Antonio G.
Published: April 2024

The behavior of steel joints under fire loading is a subject that has only recently received special attention by the research community. In fact, as recently as 1995, the European pre-standard on the fire response of steel structures deemed it unnecessary to assess the behavior of steel joints under fire conditions. This approach was supported by the argument that there is increased thermal mass at the joint area. However, observations from real fires show that, on several occasions, steel joints fail, particularly their tensile components (such as bolts or end plates), because of the high cooling strains induced by the distortional deformation of the connected members. The main objective of this paper is to describe an experimental test program carried out by the Department of Civil Engineering at the University of Coimbra on a steel sub-frame in order to evaluate the behavior of various types of steel joints under a natural fire and transient temperature conditions along the length of the beam. The tests were carried out on a purposely developed experimental installation that could reproduce the transient temperature conditions measured in the seventh Cardington test. The results of these tests provide invaluable evidence on how to design joints that are able to survive a fire.
Current Steel Structures Research No. 19
Authors: Bjorhovde Reidar
Published: April 2024

Current Steel Structures Research
Response of Concrete-Filled HSS Columns in Real Fires
Authors: Kodur Venkatesh K.R. , Fike Rustin
Published: April 2024

The use of concrete filling offers a practical alternative for achieving the required fire resistance in steel hollow structural section (HSS) columns. However, the current prescriptive-based approach has a number of constraints that in many applications restrict the utilization of concrete filling for achieving the required fire resistance. To overcome such constraints, a performance-based methodology for fire resistance design is presented in this paper. A set of numerical simulations were carried out to investigate the effect of realistic fire scenarios, loading, and stability-based failure criterion on the fire resistance of concrete-filled HSS columns with lengths ranging from 3.8 m (12.5 ft) to 10 m (32.8 ft). It is demonstrated that by adopting a performance-based approach, it is possible to achieve the required fire resistance in CFHSS columns in most practical situations.
Critical Evaluation of Equivalent Moment Factor Procedures for Laterally Unsupported Beams
Authors: Wong Edgar , Driver Robert G.
Published: April 2024

This paper compares the numerous approaches to determining equivalent moment factors used in evaluating the elastic critical moment of laterally unsupported beams for a wide variety of moment distributions. The investigation revealed that the procedure used currently in the Canadian design standard produces unacceptable results for the majority of the common bending moment distributions considered. Large abrupt changes in Cb values with only slight changes in the shape of the moment diagram were observed in six out of the 12 moment distribution comparisons, which contributes to the overall poor performance of the procedure.The study also revealed drawbacks inherent in other methods. Overall, the quarter-point moment equations developed for general moment distributions capture the trends of the numerical data reasonably well. However, for example, the evaluations show that the 2005 AISC equation produces non-conservative results in some situations, while the British equation, although generally conservative, produces comparatively less accurate results. Other equations examined capture the trends of the numerical data more consistently by implementing a square root format in the quarter-point moment method. However, they produce results that exceed the numerical data in several cases, implying that they are too aggressive for design purposes. To capture the best features of the various methods investigated, yet improve the overall suitability for general design purposes, a modified quarter-point moment equation using the square root format is proposed. Not only does it simulate the trends of the numerical solutions closely, but it also produces reasonable and conservative equivalent moment factors, even in cases where other methods do not. Like all quarter-point moment methods, the proposed equation does not produce good results in some situations where concentrated moments are applied. Nevertheless, it is believed to be appropriate for the vast majority of typical design cases.
Limit States for Horizontal Shear at a Braced Frame Beam Flange
Authors: Hungerford Brent E.
Published: April 2024

The most common design methodologies for bracing connections are based on the lower bound theorem. If the lower bound theorem is the basis cited for a steel connection design, the theorem's requirements must be satisfied. While the ductility requirement is essential to the theorem, it is the implications of the equilibrium and material strength limit requirements that will be investigated here for a portion of a common load path in a braced frame connection. Two limit states will be outlined that precisely define and expand on a limit state for web horizontal yielding. The limit states are also applicable to other types of connections with similar loading and geometry. These limit states are rational approaches to ensure that adequate resistance is provided to critical portions of a commonly assumed load path for braced frame connections. The limits likely will not control many typical braced frame configurations, but several conditions in which they may govern have been outlined for consideration. Additionally, it has been shown that it may be too conservative to require that all horizontal force from the gusset plate be transferred by shear into the beam web within the length of the gusset connection, although there are defined limits to the local beam capacity that can be obtained in these connections.
Design of Braced Frames in Open Buildings for Wind Loading
Authors: Shoemaker W. Lee , Kopp Gregory A. , Galsworthy Jon
Published: April 2024

Open-frame buildings are often used to provide a measure of weather protection over equipment or other sheltered storage on industrial sites. These shelters have a roof covering and minimal wall cladding, if any. ASCE 7 provides no guidance on the wind loads acting perpendicular to the frames that would control the design of the longitudinal braces. This paper summarizes wind tunnel tests that were performed on open-frame, low-rise buildings with a roof covering to determine the base shear and bracing loads parallel to the ridge. Two examples are provided to illustrate how the results of this study may be used to obtain the forces in longitudinal bracing.
Lightly Damped Moment-Resisting Steel Frames: A Design-Based Approach
Authors: Atlayan Ozgur , Charney Finley A.
Published: April 2024

The current U.S. seismic design provisions for steel moment-resisting frames generally result in structures for which stiffness is the controlling factor in the design. The design for stiffness often provides considerable overstrength, which reduces rotational ductility demand on the plastic hinges in the structure. Even though the reduction in ductility demand may be considerable, the design provisions do not allow the detailing rules to be waived, resulting in designs that may not be economically optimized. This paper presents the results of a study in which a variety of steel frames were designed for strength and that used added energy dissipation in the form of linear viscous dampers to control the drift. The goal of the study was to provide only enough damping to control the drift, and to this end, it was found that total system damping of 10% critical was sufficient. As shown in the paper, the added damping provided the required drift control and had the added advantage of minimizing the dispersion, which typically occurs in response history analyses carried out under several appropriately scaled ground motions. Such dispersion control is illustrated through incremental dynamic analysis of damped nine-story buildings in Seattle, Washington.
Repairable Seismic Moment Frames with Bolted WT Connections: Part I
Authors: McManus Patrick S. , Pucket Jay A.
Published: April 2024

A moment frame lateral load-resisting system was developed in which inelastic deformations due to seismic loading were intended to be isolated to easily replaceable WT components. Fully bolted connections were utilized to facilitate simple component installation and replacement. In Part I of this series, WT components for the moment frame system were modeled using finite element analysis. Full-scale component testing was performed to verify analytical results. Parameters taken from modeling and testing results were used to develop design provisions. In Part II of this series, an example building was designed using the provisions developed and analyzed under simulated earthquake accelerations to develop appropriate seismic performance factors. WT components designed using recommended geometric parameters resulted in desirable behavior. Recommended design equations correlated well to experimental test results. Experimental results suggested WT components designed using the recommended provisions exhibit adequate low-cycle fatigue performance and deflection capacity to be used with wide flange beams up to a nominal depth of 30 in. (762 mm). Nonlinear time-history analysis suggests seismic performance factors currently published for steel special moment frame systems are appropriate for the proposed WT moment frame system.
Axial Capacities of Eccentrically Loaded Equal-Leg Single Angles: Comparisons of Various Design Methods
Authors: Li Yuwen
Published: April 2024

For most structural engineers, the design of an eccentrically loaded single angle without lateral restraint along its length was considered to be a formidable task prior to the publication of the 2005 AISC Specification for Structural Steel Buildings. According to Section E5 of the 2005 Specification, the effects of eccentricity on single-angle members are permitted to be neglected by using the effective slenderness ratio as specified, provided that members are loaded at the ends in compression through the same leg; members are attached by welding or by a minimum of two-bolt connections; there are no intermediate transverse loads; the leg length ratio is less than 1.7, if angles are connected through the shorter leg; and the modified KL/r is less than or equal to 200. The 13th edition AISC Steel Construction Manual provided a design table (Table 4-12) of the available strengths in axial compression of eccentrically loaded single angles, with the assumption that the compressive force is applied at the geometric y-y axis at a distance of 0.75t from the back of the connected leg, where t is the angle thickness. Table 4-12 has been revised in the 14th edition AISC Steel Construction Manual. The new table corrects some numerical errors in the calculations and moves the compressive force to the midpoint of the connected leg. The values of the axial compressive design strength in Table 4-12 are developed on the basis of bending about the principal axes w-w and z-z.
Current Steel Structures Research No. 32
Authors: Bjorhovde Reidar
Published: April 2024

Current Steel Structures Research
Composite Action of Concrete Slab and Open Web Joist (Without the Use of Shear Connectors)
Authors: Wang P.C. , Kaley D.J.
Published: April 2024

The advantage of composite action of concrete slab and steel beam in increasing load carrying capacity and structural stiffness has been well recognized. The American Institute of Steel Construction in its 1963 Specification has given the explicit methods of analysis. However, it restricts the composite action to only fully encased beams or beams with properly designed shear connectors. In the case of concrete slab and steel open web joist, limited study of composite action has been made. As demonstrated in the Discussion of Results, composite action exists in the K-composite system of reinforced concrete slab and open web steel joist construction. This system acts compositely and therefore reduces deflections and member stresses appreciably. Comparison of data illustrates that mid-span deflections were reduced to 39.8 percent and the maximum lower chord stresses were reduced to 78.1 percent of a comparable noncomposite structure. Based on the results of these tests, corrugated sheet construction exhibits some composite action up to a lower load level, depending on the strength of the plug welds between the welding washers and the top flange of the joist.
Design of Braced Multi-Story Frames by the Plastic Method
Authors: Lu Le-Wu
Published: April 2024

Since 1956 an extensive research program has been carried out at Lehigh University to study the inelastic behavior and strength of multi-story frames subjected to various types of applied loads and to develop design methods utilizing the reserved strength in the inelastic range. In this program, because of the difference in load-carrying behavior, multistory frames were divided into two types: braced and unbraced frames, and a separate investigation was made for each type. The results obtained from this research together with the recommended design procedures were presented in a comprehensive set of lecture notes and a design aids booklet, which were prepared for a special Summer Conference on "Plastic Design of Multi-Story Frames" held in August, 1965, at Lehigh University. This paper summarizes the procedure described in the lecture notes for the design of braced frames. A braced frame is defined as a frame in which all resistance to lateral force, sway and frame instability is provided by a specially designed bracing system. The required member sizes for the beams and columns in such a frame are often governed by gravity load. It is therefore possible in the initial stage of design to treat the frame and the bracing as two separate load-carrying systems and to perform independent designs for them. The interaction between the frame and the bracing system is then checked after the approximate member sizes are selected.
Plastic Design of a 14-Story Apartment Building
Authors: Bennett William A.
Published: April 2024

The subject of this paper is the plastic design of the steel frame of the 14-story Binghamton Apartment Tower in Binghamton, N. Y.. The design method used was that advanced by the authors of the Lehigh University lecture notes entitled Plastic Design of Multi-Story Frames. The Lehigh notes provide analytical methods for both braced and unbraced frames. The unbraced frame method was used for this project because architectural considerations prevented the use of X-bracing or shear walls. Sample calculations taken from the actual design sheets are included in an Appendix to illustrate the design methods and techniques described.
A Prestressed Steel Space Frame
Authors: Rogers Paul
Published: April 2024

The St. John Brebeuf Roman Catholic Church, Niles, Ill., completed in early 1966, reflects the contemporary trend toward circular houses of worship. The interior layout is arranged so that the priest and altar are virtually surrounded by the parishioners. The building is 180 ft in diameter and has a 144-ft diameter flat conical dome topped by a 49-ft high tower and 26-ft high cross. Figure 1 shows a general view of the church. A uniformly distributed live load of 25 psf was used in the design. The architectural concept required that interior supporting columns be eliminated, yet the structure was required to support an imposing tower with stained glass windows.
Discussion: Plastic Design of Eccentrically Loaded Fasteners
Authors: Fisher John W. , Abolitz A.L.
Published: April 2024

Discussion
Simplified Procedure to Determine Maximum Beam Deflection
Authors: Koo Benjamin
Published: April 2024

The maximum deflection of a beam occupies an important role in discussions concerning structural design. Building codes such as ACI-63 and the AISC Specification limit the deflection caused by a live load to 1/360 of the beam span. Beam design calculations to meet the specifications usually involve tedious and lengthy computations. In this paper, the following simplified procedure is proposed: For any beam of variable moment of inertia, subject to end moments and lateral loads, first use matrix multiplication to determine a segment where maximum deflection will occur. Then, using boundary conditions of the segment, repeat matrix multiplication to obtain the maximum deflection.
Generalized Superposition Method in Plastic Analysis
Authors: Pincus George
Published: April 2024

A recent description of the method of combining mechanisms in plastic analysis has been presented. Further refinements in the use of the method have been developed and are presented herein. These include the use of a sign convention in determining plastic rotation angles and a tabular arrangement for the ultimate load of independent and combined mechanisms arising out of two independent mechanisms. Constant comparison of the magnitude of theultimate loads is then possible while the use of the sign convention in calculating the ultimate loads of composite mechanisms immediately eliminates some of the possible combinations from consideration.
A Flexibility-Based Formulation for the Design of Continuity Plates in Steel Special Moment Frames
Authors: Tran Andy T. , Hassett Patrick M. , Uang Chia-Ming
Published: April 2024

This paper introduces a rational approach for the design of continuity plates and associated welds in steel special moment frame (SMF) connections. The current AISC Seismic Provisions require welds attaching continuity plates to develop the full strength of the plate, resulting in the need to use complete-joint-penetration (CJP) groove welds. The combination of continuity plate thickness requirements, welding process and weld inspection often leads to costly detailing that may be overly conservative. The proposed design procedure, which is based on the relative flexibility between the column flange and continuity plate, aims to quantify the seismic force demand on continuity plates, thus allowing designers to efficiently size both the continuity plate thickness and the associated welded joints. In addition, the design procedure may allow the use of fillet welds or partial-joint-penetration groove welds as opposed to CJP welds, leading to a more economical design and fabrication. Formulation of the design procedure through analytical studies, including finite element analysis, is outlined.
Structural Fire Engineering: Overview and Application Examples of Appendix 4 of the AISC Specification
Authors: Gross John , Iwankiw Nestor , Johann Matthew
Published: April 2024

This paper presents an overview of current conventional practices for providing passive fire protection of building structures and describes alternative engineering approaches covered in Appendix 4 of the 2010 AISC Specification, ANSI/AISC 360-10. The concept of structural fire engineering is discussed, along with guidance and design references that are available to support performance-based structural fire engineering analyses. The roles and responsibilities typically assumed by design team members and other stakeholders in a structural fire engineering project are presented, as are considerations associated with peer reviews and approval by authorities having jurisdiction. The paper concludes with a series of four design examples that demonstrate a range of structural fire engineering applications for steel buildings.
Current Steel Structures Research No. 34
Authors: Bjorhovde Reidar
Published: April 2024

Current Steel Structures Research
Current Steel Structures Research No. 35
Authors: Bjorhovde Reidar
Published: April 2024

Current Steel Structures Research
Two-Way Bending of Base Plates under Uniaxial Moment Loading--Alternative Approach
Authors: Haninger Edward R. , Tong Bruce M.
Published: April 2024

This Technical Note presents an alternate model for two-way bending design of column base plates under uniaxial moment loading and is based on the design premises of AISC Design Guide 1, Base Plate and Anchor Rod Design (Fisher and Kloiber, 2006). Two-way bending, in this paper, refers to bending of a column base plate in the direction perpendicular to the primary direction of bending and is also called side bending. When two-way bending governs, which is commonly the case, this procedure results in more efficient base plates that more closely reflect available strengths. A sample calculation is also provided.
Structural Innovation: Combining Classic Theories with New Technologies
Authors: William F. Baker Lauren L. Beghini
Published: April 2024

In the early stages of the design process, an engineer sets the geometry of the structure. The decisions made about the layout of the structure will determine the overall efficiency that can be achieved and the magnitude of the forces that must be accommodated. For example, the deflection of a truss can actually be decreased by removing material if a geometry is created that has a shorter total load path. This paper presents concepts and methodologies for creating and understanding efficient geometries. It starts with a review of the 19th- and 20th-century load path theories of Rankine, Maxwell, Cremona and Michell. It then combines their insights with current topology optimization and shape-finding tools as a means of exploring how engineers can create structural geometries that improve the behavior and reduce the tonnage of their designs. Several examples of classical theoretical solutions are explored along with their application to new designs.
Fatigue Testing and Retrofit Details of High-Mast Lighting Towers
Authors: Ryan J. Sherman Matthew H. Hebdon and Robert J. Connor
Published: April 2024

Fatigue cracking has been the cause of a number of high-mast lighting tower (HMLT) failures throughout the United States. In almost every case, forensic evaluations have shown cracking initiates and propagates due to wind-induced fatigue at mainly the base plate–to–tube wall connection detail or the hand-hole weld detail. Simply replacing the towers is not an economically feasible alternative because thousands of HMLTs are in use along major highways across the United States. As a result, strategies to retrofit existing HMLTs are needed. Results from laboratory testing performed on two HMLT retrofit configurations are presented. The retrofit strategies are employed without removing the pole from the foundation using simple bolting techniques and moderately skilled labor, providing cost savings for owners and increasing safety for the motoring public.
Finite Element Modeling of Steel Moment Connections with Fracture for Structural Fire Analyses
Authors: Mina Seif Therese Mcallister
Published: April 2024

Performance-based methodologies to evaluate the fire performance of structures are needed to move beyond the prescriptive procedures currently in use, which cannot be used to determine actual structural performance in fire. Analytical methods are needed for simulating the performance of structural systems, including connections, subject to realistic fire effects. Framing connections may be subject to large, unanticipated deformations and loads during fire events, and connection failure may lead to other failures or local collapse. This paper presents the development of detailed finite element models of typical moment connections for steel-framed structures. These detailed models incorporate temperature-dependent material models that have been calibrated against available test data from tensile coupons, including the modeling of necking behavior and fracture. Connection performance at ambient and elevated temperatures is evaluated, and dominant failure modes are identified.
Cross-Section Strength of Circular Concrete-Filled Steel Tube Beam-Columns
Authors: Denavit Mark D. , Hajjar Jerome F. , Leon Roberto T.
Published: April 2024

Closed-form expressions for the cross-section strength of steel-concrete composite beam-columns according to the plastic stress distribution method are tabulated in the AISC Seismic Design Manual and the AISC Design Examples. Approximations have been used in the deriva- tion of these formulas, most of which do not significantly affect the accuracy of the results. However, an approximation in the equation for the axial strength of circular, concrete-filled steel tubes that are simultaneously subjected to flexure at one of the key points on the interaction curve (designated as Point E) leads to results that are unconservative. The derivation of the equation is reviewed and a more accurate expression is proposed.
Dynamic Shear Strength of Riveted Structural Connections
Authors: Rabalais Christopher P. , Crane C. Kennan
Published: April 2024

Riveted lap-spliced specimens were tested to observe how the fasteners’ shear strengths were affected by joint configuration, number of shear planes, and loading type. A 200,000-lbf-capacity dynamic loader was used to fail the specimens under a monotonic dynamic or monotonic quasi-static load. The test data were normalized by the number of shear planes loaded in each test and estimated ultimate tensile strength of the driven rivet. A statistical analysis was conducted to determine the significant factors affecting the fastener shear strength. Conclusions from the analyses indicated that the loading type has the most significant effect on shear capacity, resulting in a dynamic increase factor of 1.72 relative to the rivet’s quasi-static shear capacity.
Stability of Rectangular Connection Elements
Authors: Dowswell Bo
Published: April 2024

Connection elements are commonly designed using the flexural buckling and lateral-torsional buckling provisions in AISC Specification Sections E3 and F11, respectively, as well as the combined-load requirements of Section H1. Because these provisions were developed for main members, their accuracy for designing connection elements is questionable. The factors affecting the stability of connection elements are discussed, with an emphasis on the differences between main members and connection elements. The available experimental and theoretical results are compared to the AISC Specification equations. Where required, new equations are derived, and practical design solutions are recommended. Recommendations are also made for connection elements subjected to combined axial and flexural loads. Examples are provided to illustrate the proposed design procedures for double-coped beams.
Steel Structures Research Update: Ring-Shaped Steel Plate Shear Walls for Improved Seismic Performance of Buildings
Authors: Liu Judy
Published: April 2024

Recently completed work on the innovative ring-shaped steel plate shear wall (RS-SPSW) is highlighted. The research was led by Dr. Matthew Eatherton, Associate Professor at Virginia Tech and an AISC Milek Fellow. Featured here is the research conducted at Virginia Tech, with a brief discussion of the RS-SPSW concept and behavior; a summary of the large-scale experiments; and selected nonlinear response history analysis results comparing conventional SPSW and RS-SPSW prototype buildings.
Minimum Requirements and Section Detailing Provisions for Steel-Plate Composite (SC) Walls in Safety-Related Nuclear Facilities
Authors: Bhardwaj Saahastaranshu R , Varma Amit H. , Malushte Sanjeev R.
Published: April 2024

Steel-plate composite (SC) walls are comprised of concrete walls sandwiched between steel faceplates located on the exterior surfaces. These faceplates are anchored to the concrete infill using steel anchors and connected to each other using ties. SC walls have been used extensively in the third generation of nuclear power plants and are also being considered for small modular reactors (SMRs) of the future. The American Institute of Steel Construction (AISC) has published Supplement No. 1 to AISC N690, which includes Appendix N9 for the design of SC walls in safety-related nuclear facilities. This paper presents the minimum requirements for SC walls and the section detailing provisions from Appendix N9 along with their basis. The minimum requirements include requirements for minimum and maximum SC wall thickness, faceplate thickness, and steel and concrete material strengths. The provisions of Appendix N9 are applicable to SC walls that satisfy these minimum requirements. The design provisions account for the effects of interaction between out-of-plane shear demands (in both x- and y-directions) and the corresponding interfacial shear demands while accounting for the differences in behavior between yielding and nonyielding steel anchors and ties as classified by AISC N690 Supplement No. 1.