Experimental Investigation of Reduced Beam Section Moment Connections without Continuity Plates

The AISC 2002 Seismic Provisions for Structural Steel Buildings recommend that usage and sizing of beam flange continuity plates across the column web shall be based on tests. The Recommended Seismic Design Criteria for New Steel Moment-Frame Buildings ( FEMA-350) state that unless project-specific testing is performed to demonstrate that continuity plates are not required, moment-resisting connections should be provided with continuity plates when the thickness of the column flange is below a minimum value. One of the preferred moment connections for seismic-resistant steel frames is the reduced beam section (RBS) moment connection, which has performed well under cyclic loads in laboratory testing. To demonstrate the effectiveness of the RBS moment connection without continuity plates in the panel zone, a series of four full-scale tests of exterior beam-column connections was carried out. All materials were A572 Grade 50 steel; the beams were W30×132, two of the assemblies used W14×283 columns, and the other two used W18×211 columns. The beams were welded to the columns using complete joint-penetration welds. All four tests demonstrated that the RBS connections without continuity plates developed a total interstory drift angle greater than 0.04 radians and met the requirements for special moment frames.

Download Full-text

RBS moment connection analysis using a solid model

10.32920/ryerson.14635773 ◽

2021 ◽

Author(s):

Mikaela Coello-Mena

Keyword(s):

Seismic Event ◽

Plastic Hinge ◽

Efficient Design ◽

Moment Connections ◽

Reduced Beam Section ◽

Moment Connection ◽

Steel Moment Connection ◽

Cutting Out ◽

Beam Section ◽

Rbs Connections

The unpredictability of the steel beam welding connection has led to many solutions, including the are of focus for this research Reduced Beam Section ( Moment Connections The RBS in steel moment connection facilitates the calculation and predictability of failure in design The RBS section is created by cutting out part of the flanges in a beam This creates a plastic hinge where the beam will fail first 1 This creates a model of predictability on the durability and strength of the beams Creating a RBS connection increases the overall ductility of the steel frame The RBS section reduces the flange width which causes stress concentration on the reduced section and this then lowers the stress on the welds. The lower stress then prevents unexpected brittle fracture in the welding a predicted plastic deformation of the RBS section during a seismic event 2 3 The research is focused on optimizing the RBS connection Finite models will be created using ANSYS to investigate how different RBS connections react in different situations and what is the most efficient design in terms of safety and cost.

Download Full-text

RBS moment connection analysis using a solid model

10.32920/ryerson.14635773.v1 ◽

2021 ◽

Author(s):

Mikaela Coello-Mena

Keyword(s):

Seismic Event ◽

Plastic Hinge ◽

Efficient Design ◽

Moment Connections ◽

Reduced Beam Section ◽

Moment Connection ◽

Steel Moment Connection ◽

Cutting Out ◽

Beam Section ◽

Rbs Connections

Download Full-text

Design Approach To Bolted End-Plate Vertical-Slits RWS Connection

10.21203/rs.3.rs-308954/v1 ◽

2021 ◽

Author(s):

Hamidreza Nazaralizadeh ◽

Hamid Ronagh ◽

Parham Memarzadeh ◽

Farhad Behnamfar

Keyword(s):

Numerical Models ◽

Design Procedure ◽

Cost Effective ◽

Design Parameters ◽

Moment Frames ◽

Steel Moment Frames ◽

Reduced Beam Section ◽

End Plate ◽

Beam Section ◽

Rbs Connections

Abstract Extensive research has been carried out on steel moment frames to improve the cyclic performance of seismic resisting connections with reduced beam section (RBS). The RBS connections are conventionally known by the radial reduction of the beam flange. Where the contribution of the beam flange to the flexural resistance is greater than that of the beam web, some researchers have proposed reduced web section (RWS) connections, instead. The present study dedicates to the RWS connections with vertical-slits (VS), as a cost-effective alternative with multiple design parameters. This paper aims to obtain proper ranges for the geometric design parameters of the VS-RWS connection. In this order, two full-scale specimens of the bolted end-plate VS-RWS connection were experimentally tested under the SAC cyclic loading to evaluate the performance of connections, and then a parametric study was carried out using the verified numerical models. The parameters consist of the distance between the column face and the beginning of the reduced region, the length of the reduced region, as well as the depth and width of the vertical-slits. Based on the results, certain recommendations for the ranges of the geometric parameters of VS-RWS have been suggested. In order to obtain the story drift of the frame caused by the VS-RWS beam flexural deformation using the conjugate beam method, the original VS-RWS was replaced with an equivalent constant-cut reduced beam section (CC-RBS). At last, a simple design procedure for VS-RWS connections was provided according to AISC-358.

Download Full-text

Fracture Moment Strength of Reduced Beam Section with Bolted Web Connections

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.348-349.717 ◽

2007 ◽

Vol 348-349 ◽

pp. 717-720

Author(s):

Ki Hoon Moon ◽

Sang Whan Han ◽

Ji Eun Jung

Keyword(s):

Moment Connections ◽

Moment Capacity ◽

Design Procedures ◽

Reduced Beam Section ◽

Moment Resisting ◽

Current Design ◽

Beam Section ◽

The Moment ◽

Rbs Connections ◽

Experimental Researches

Reduced Beam Section (RBS) moment connections are developed for Special Moment Resisting Frames (SMRF). According to the beam web attachment the column flange RBS connections are classified into Reduced Beam Section with Bolted web connections (RBS-B), and the Reduced Beam Section with Welded web connections (RBS-W). Beam flanges are welded to the column. Regardless of different web attachment details in RBS-B and RBS-W connections current design procedures (FEMA 350) assumes that they could develop plastic moment of the beam gross section. In current design procedures, RBS-B connections should provide the sufficient strength that can reach the plastic moment capacity of the connected beam. However, some experimental researches reported that the beams in RBS-B connections fractured before the connection reached its plastic moment capacity. Such undesirable fracture shows that RBS-B connections have less strength than RBS-W connections. And if RBS-B connections designed in current design procedures, it might fail in a brittle manner and not satisfy SMRF due to undesirable fracture. Thus, this study develops a new set of equations for accurately computing the moment strength of RBS-B connections. The proposed strength equation accurately predicts connection moment capacity for RBS-B connections.

Download Full-text