International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 11 Issue: 06 | Jun 2024
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p-ISSN: 2395-0072
Seismic Enhancement of RBS with Pretension Bolt in Steel Moment Resisting Frame. Ashina T. R1, Fathima S Thaikudiyil2, Dr. George K George3 1Post Graduate student, Department of Civil Engineering, KMEA Engineering College, Edathala Ernakulam. Kerala 2Assistant Professor, Department of Civil Engineering, KMEA Engineering College, Edathala Ernakulam, Kerala
3 Assistant Professor, Department of Civil Engineering, KMEA Engineering College, Edathala Ernakulum, Kerala
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Abstract - Reduced beam section design provides a more
ability to withstand strong earthquake forces. Seismic stability joints are designed to provide controlled yielding and energy dissipation during seismic events. These joints are typically located at specific levels along the height of the MRF, such as at beam-column connections or at the base of the structure. The performance of seismic stability joints is critical in ensuring the overall stability and safety of MRFs during earthquakes. These joints must be designed to have sufficient strength and ductility to withstand the anticipated seismic forces without failure. Additionally, their behaviour under cyclic loading conditions should be carefully considered to ensure that they can sustain multiple seismic events without significant degradation in performance. Several factors need to be considered in the design and evaluation of seismic stability joints. These include the selection of appropriate joint types, such as fuse elements or energy dissipating devices, as well as the determination of their capacity and behaviour under different loading conditions. The detailing of these joints is also crucial to ensure proper load transfer and avoid potential weak points or failure modes
predictable and reliable behavior at the beam column connection during seismic event. RBS enhances the ductility of the beam and it made the column safe from overall collapse of a structure but it reduced the load bearing capacity of beam considerably.to overcome the lack of moment capability of beam this study aims to implement a pretensioning bolt with plate welded across the RBS. The main objective of this paper is to evaluate the performance of reduced beam section(RBS) with various design modification, specifically focusing on strengthening methods involving bolts and plates. The study aims to determine whether the diameter of bolts used in these strengthened RBS designs influences the load bearing capacity of the beam. Key Words: Reduced beam section, load bearing capacity, collapse, beam, column, bolts.
1.INTRODUCTION. A moment resisting frame (MRF) is a structural system commonly used in buildings to resist lateral loads, such as those generated by wind or earthquakes. It consists of beams and columns connected together to form a rigid frame that can transfer and distribute these loads throughout the structure. MRFs are highly efficient in terms of material usage and construction costs. They can provide a high strength-to-weight ratio, allowing for lighter and more economical designs compared to other structural systems they offer flexibility in architectural design by providing open floor plans with minimal obstructions. The absence of diagonal bracing allows for more usable space and better utilization of the building. MRFs can provide an aesthetically pleasing appearance due to their clean and unobstructed structural lines. This makes them suitable for modern architectural designs. MRFs typically have redundant load paths, meaning that if one member fails, the load can be redistributed to other members. This enhances the overall robustness and resilience of the structure. robustness and resilience of the structure.
During 1994 Northridge, CA earthquake, the beam flangecolumn flange weldments in steel MRF failed at much lower than anticipated load and drift levels. Thus structural engineers introduced RBS, which appears to the most economical new design method. The RBS protects the welded connection by forcing the plastic hinge in a beam to form away from the column face. Traditionally itβs a strong column weak beam combination Reduced Beam Sections (RBS) design provides a more predictable and reliable behaviour at the beam-column connection during seismic events. The purpose of an RBS is to enhance the ductility of the beam. By reducing the beam section's width and depth at the ends, the plastic hinge formation can be controlled and confined within the reduced section. This allows for controlled yielding and energy dissipation during seismic events or other loading conditions, improving the overall ductility of the beam. Providing reduced beam sections on beams instead of the beamcolumn interface allows for improved ductility, maintains the flexural capacity of the beam, preserves the column's design integrity, and facilitates construction processes. The disadvantage faced in RBS is that it reduced the moment capacity.
Lateral stability is a crucial aspect in the design and performance of moment resisting frames (MRFs) during seismic events. Seismic stability joints are commonly used in MRFs to enhance their lateral stability and ensure their
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