J.R. Ubejd Mujagic

The soon-to-be-released 2022 version of the AISC Specification brings flexibility and
innovation to composite beam design with the introduction of a performance-based
alternative for shear connections.

Mujagic, J.R.U., Easterling, W.S., Bennett, J.S. and Varma, A.H. (2015) “Assessment of Shear Connection Ductility in Composite Beams – Implications on the U.S. Design Practice,” Report No. CE/VPI-15/12, Virginia Polytechnic Institute and State University, Blacksburg, VA.

This practical reference discusses the types of low-rise building structural systems, outlines the design process, and explains how to determine structural loadings and load paths pertinent to low-rise buildings. Characteristics and properties of materials used in the construction of cold-formed steel, reinforced masonry, and structural timber buildings are described along with design requirements. The book also provides an overview of non-composite and composite open-web joist floor systems… Show more

This practical reference discusses the types of low-rise building structural systems, outlines the design process, and explains how to determine structural loadings and load paths pertinent to low-rise buildings. Characteristics and properties of materials used in the construction of cold-formed steel, reinforced masonry, and structural timber buildings are described along with design requirements. The book also provides an overview of non-composite and composite open-web joist floor systems. Design code requirements referenced by the 2009 International Building Code are used throughout. This is an ideal resource for structural engineering students, professionals, and those preparing for licensing examinations. Show less

This full-day seminar covers structural design of connections used in cold-formed steel applications, including decks and framing. The course will review the requirements of 2007 AISI North American Specification & Supplement 2 as well as the AISI framing standards to meet the provisions of 2009 IBC.

The presentation provides an overview of cold-formed steel (CFS) connection design concepts listed in chapter E of the American Iron and Steel Institute (AISI) North American Specification for the Design of Cold-Formed Steel Structural Members (AISI S100), as specified in the 2009 International Building Code (IBC). It covers in detail screw connections, the most common for CFS construction, as well as welded and bolted CFS connections. In addition, it also covers connections not included in… Show more

The presentation provides an overview of cold-formed steel (CFS) connection design concepts listed in chapter E of the American Iron and Steel Institute (AISI) North American Specification for the Design of Cold-Formed Steel Structural Members (AISI S100), as specified in the 2009 International Building Code (IBC). It covers in detail screw connections, the most common for CFS construction, as well as welded and bolted CFS connections. In addition, it also covers connections not included in the specification such as Power actuated fasteners as well as anticipated upcoming changes in design provisions for screws welds and bolts. IBC and International Code Council Evaluation Service testing requirements are also covered. Show less

Abstract
Composite steel–concrete flexural members have become increasingly popular in the design and construction of floor systems, structural frames, and bridges. A subtype of such composite floors is a system featuring composite trusses, also referred to as composite open-web joists, which can span large lengths and provide open web space for the installation of typical utility conduits. One problem that arises with respect to composite joists has been the installation of welded shear… Show more

Abstract
Composite steel–concrete flexural members have become increasingly popular in the design and construction of floor systems, structural frames, and bridges. A subtype of such composite floors is a system featuring composite trusses, also referred to as composite open-web joists, which can span large lengths and provide open web space for the installation of typical utility conduits. One problem that arises with respect to composite joists has been the installation of welded shear studs. In many composite trusses, the composite action can significantly reduce the required size and thickness of the top chord. The thinner the top chord member becomes, the more difficult it is to weld studs without burning through the base member. Likewise, as the joists get smaller, the greater the sweep (lateral out-of-straightness) tends to become. For these reasons, a form of shear connector other than welded shear studs is of interest. The results of the elemental push-out tests, analytical study and the resulting strength prediction models for the strength of the shear connection have previously been presented by the authors. This paper presents the analytical and experimental findings pertaining to the design and behavior of composite truss members with standoff screws as shear connectors. Show less

ABSTRACT
Power-actuated fasteners (PAFs), also referred to as pins, are small
nail-like or threaded stud type connectors. They can be used in conjunction with
several materials and in a number of different applications. Typical applications
in steel include attachments of deck sheeting or diaphragms, architectural or
mechanical components, or miscellaneous support brackets or connections to
supporting steel members. Traditionally, the design strength of the… Show more

ABSTRACT
Power-actuated fasteners (PAFs), also referred to as pins, are small
nail-like or threaded stud type connectors. They can be used in conjunction with
several materials and in a number of different applications. Typical applications
in steel include attachments of deck sheeting or diaphragms, architectural or
mechanical components, or miscellaneous support brackets or connections to
supporting steel members. Traditionally, the design strength of the connections
featuring power-actuated fasteners has been determined through standardized
testing protocols. In the United States, this protocol is embodied in the
American Society for Testing and Materials (ASTM) Standard E 1190. The
purpose of this study was to create a generic strength prediction model for pins
embedded in steel substrate and subjected to either shear or tension, and to
present the equations in a limit states format applicable to the North American
practice and applications. Show less

Abstract
Composite steel–concrete flexural members have become increasingly popular in the design and construction of floor systems, structural frames, and bridges. Constant research advances have resulted in numerous enhancements and changes to the American design practice, as embodied in the composite construction provisions of AISC Specification. This paper presents results of a comprehensive reliability study of composite beams. The study considers Specification changes since the 1976… Show more

Abstract
Composite steel–concrete flexural members have become increasingly popular in the design and construction of floor systems, structural frames, and bridges. Constant research advances have resulted in numerous enhancements and changes to the American design practice, as embodied in the composite construction provisions of AISC Specification. This paper presents results of a comprehensive reliability study of composite beams. The study considers Specification changes since the 1976 reliability study by Galambos and Ravindra, considers a larger database of experimental data, and evaluates recent proposals for changes in the design of shear connectors. A comparison of three different design methods is presented based on 15,064 composite beam cases. A method to consider the effect of the degree of shear connection on the strength reduction factor is proposed. Show less

Connections in Cold-Formed Steel Framing – Designing with AISI 2007 - Specification and Application Overview

Abstract
Composite steel–concrete flexural members have become increasingly popular in the design and construction of floor systems, structural frames and bridges. A particularly popular system features composite trusses (open web joists) that can span large lengths and provide open web space for installation of typical utility conduits. One problem that arises with respect to composite joists has been the installation of welded shear studs. As the joist span gets smaller, the top chord also… Show more

Abstract
Composite steel–concrete flexural members have become increasingly popular in the design and construction of floor systems, structural frames and bridges. A particularly popular system features composite trusses (open web joists) that can span large lengths and provide open web space for installation of typical utility conduits. One problem that arises with respect to composite joists has been the installation of welded shear studs. As the joist span gets smaller, the top chord also gets smaller. The thinner the top chord member becomes, the more difficult it is to weld studs without burning through the base member. Likewise, as the joists get smaller, the greater the sweep (lateral out-of-straightness) tends to become. For these reasons, a form of shear connector other than welded shear studs is of interest. This paper presents research results for a new type of shear connector, the standoff screw. This type of connector is drilled, rather then welded, and represents a viable alternative to headed shear studs in light composite trusses or open web joists. Results of experimental and analytical research are presented, as well as the development of a recommended design methodology. Show less

Current design provisions for steel-concrete composite beams rely upon a strength-based approach as outlined by the AISC Specification. In partial composite beams, the headed studs transferring interfacial shear between the concrete and steel can undergo significant slip, which is not accounted for directly in design. A numerical model was developed and benchmarked to calculate the flexural capacity of partially composite beams while accounting for slip at the steel-concrete interface. This… Show more

Current design provisions for steel-concrete composite beams rely upon a strength-based approach as outlined by the AISC Specification. In partial composite beams, the headed studs transferring interfacial shear between the concrete and steel can undergo significant slip, which is not accounted for directly in design. A numerical model was developed and benchmarked to calculate the flexural capacity of partially composite beams while accounting for slip at the steel-concrete interface. This paper presents the results of parametric studies that were conducted to evaluate the effects of various geometric and material parameters including percent composite action, beam length, and cross-section geometry. The calculated flexural capacities were compared with the corresponding nominal design strengths calculated using the AISC Specification. These comparisons indicated that longer composite beams with low levels of composite action (less than 50%) reached the shear stud slip capacity before developing their nominal (AISC) design strength. This reveals the complex inter-relationship between the beam length, stud slip capacity, and the minimum level of partial composite action that may be permitted for design. Show less

The 2016 edition of the AISC Specification will feature several
changes in the design for ponding. An overview of the changes
will be provided, focusing on the theoretical background of the
methodology given in Appendix 2 of AISC 360-16. The interface
with ASCE 7 and IBC will be detailed. The session will focus on
numerical implementation of the design approaches for practical
ponding design. Case studies will be reviewed to illustrate
application challenges and… Show more

The 2016 edition of the AISC Specification will feature several
changes in the design for ponding. An overview of the changes
will be provided, focusing on the theoretical background of the
methodology given in Appendix 2 of AISC 360-16. The interface
with ASCE 7 and IBC will be detailed. The session will focus on
numerical implementation of the design approaches for practical
ponding design. Case studies will be reviewed to illustrate
application challenges and considerations. Show less