Columns in partially restrained construction: analytical studies

1987 ◽  
Vol 14 (4) ◽  
pp. 485-497 ◽  
Author(s):  
David A. Nethercot ◽  
Patrick A. Kirby ◽  
Abdussalam M. Rifai
Keyword(s):  
Structural Design ◽  
Analytical Procedure ◽  
Load Path ◽  
American Institute ◽  
Load Paths ◽  
Factor Design ◽  
Definition Of ◽  
Partially Restrained ◽  
Load And Resistance Factor ◽  
End Restraint

The American Institute of Steel Construction Proposed Load and Resistance Factor Design Specification recognizes the ability of connections that function as less than fully rigid to transmit limited moments and to provide some measure of end restraint to columns in its definition of partially restrained (PR) construction. An analytical procedure for determining the response up to collapse of subassemblages in which semirigid beam-to-column connections are present is derived. This employs a nonlinear finite element column analysis together with analytical representation of experimentally determined connection moment–rotation [Formula: see text] curves. To trace the full response under any load path produced by a combination of beam loads and direct column load, it is necessary to allow for possible reversal in the direction of rotation of any of the connections. The program is used to study the effect of different connection types (ranging from very flexible web cleats to almost rigid extended end plates) and different load paths on column behaviour in nonsway subassemblages. It is found that the degree of rotation required from each connection is an important parameter in determining column response. Key words: buckling, columns, connections, frames, stability, steel, structural design, structures.

scholarly journals Perancangan Kolom Struktur Gable Frame Untuk Berbagai Bentang Lebar Bangunan

2020 ◽  
Vol 23 (1) ◽  
Author(s):  
Marsiano Marsiano ◽  
Fajar Fajar
Keyword(s):  
Resistance Factor ◽  
American Institute ◽  
Factor Design ◽  
Load And Resistance Factor

Struktur Gable Frame merupakan salah satu alternatif didalam mendesain bangunan baja. Strukturdengan bentang lebar antara 40 - 60 meter mengakibatkan harus menempatkan kolom tambahan di tengah. Halini menjadikan perlunya dilakukan penelitian terhadap penempatan kolom tengah. Dengan bentang bangunanyang berbeda, sudut kemiringan atap ditentukan sebesar 3 derajat, serta menggunakan Atap Metal sebagaipenutup atapnya. Studi dilakukan dengan mengamati lima variasi bentang (40, 45, 50, 55 dan 60 meter), sertaalternatif penempatan kolom tengah pada setengah bentang, pada sepertiga bentang dan pada seperempatbentang. Mutu baja yang digunakan adalah ST 37 dan profil WF. Yang akan diamati pada penelitian ini adalahdesain yang ekonomis dan mudah dalam pelaksanaannya. Digunakan program perhitungan struktur ETABSdalam mencari gaya-gaya yang bekerja pada setiap batangnya. Serta peraturan AISC (American Institute of SteelConstruction) untuk perhitungan perencanaan rangka atap tersebut. Proses perhitungan dilakukan berdasarkanprinsip desain keadaan batas yang diacu oleh AISC sebagai LRFD (Load and Resistance Factor Design) sertaperaturan SNI (Standar Nasional Indonesia). Dalam analisa perbandingan ini dapat disimpulkan bahwa lebihbaik menggunakan desain ketiga yaitu desain dengan jarak seperempat bentang, dimana desain tersebut lebihekonomis dari segi berat struktur 1 portalnya dengan nilai yang lebih kecil dibandingkan dengan desain pertamadan kedua. Dari segi berat struktur 1 portal dapat dirata-ratakan bahwa Tipe 1 lebih ekonomis 11,6 % jikadibandingkan dengan Tipe 2, dan Tipe 2 lebih boros 21,7 % jika dibandingkan dengan Tipe 3 serta Tipe 1 lebihboros 7,3 % jika dibandingkan dengan Tipe 3.

scholarly journals The Route That Forces Take

2008 ◽  
Vol 130 (09) ◽  
pp. 39-42
Author(s):  
James G. Skakoon
Keyword(s):  
Human Factor ◽  
Mechanical Design ◽  
Design Tool ◽  
Engineering Analysis ◽  
Force Transmission ◽  
Load Path ◽  
Analytical Design ◽  
Load Paths ◽  
Potential Problems ◽  
Factor Design

This article discusses that visualizing the load path in a design can uncover areas open to improvement. Planning the force transmission path during mechanical design is hardly dazzling engineering analysis, but explicitly doing so will improve your designs. By visualizing the transmission of forces, one can eliminate unnecessary parts, strengthen the design, and identify potential problems for further analysis or correction. Visualizing the path of transmitted forces for cables is pretty easy; forces follow the tension cables. But it is only slightly more complex with compression and shear involved. Although design is never a strictly linear progression, reviewing and refining the load path should be a formal part of the design process. Troubles with the load path in user-centered device design may become obvious with testing, but thinking about load paths as a human factor design issue can save time and effort. It is not a highly analytical design tool, but visualizing and refining load paths in structures and mechanisms is extraordinarily useful for designers, and it’s simple.

Background information for some of the proposed earthquake design provisions for the 2005 edition of the National Building Code of Canada

2003 ◽  
Vol 30 (2) ◽  
pp. 279-286 ◽  
Author(s):  
Ronald H DeVall
Keyword(s):  
Structural Design ◽  
Building Code ◽  
Background Information ◽  
Load Path ◽  
Special Design ◽  
Load Paths ◽  
Irregular Structures ◽  
Earthquake Design ◽  
Importance Factor ◽  
Design Requirements

There are many changes proposed for the Earthquake Design Provisions of the 2005 edition of the National Building Code of Canada (NBCC). Among them are requirements for complete load paths, separation of stiff nonstructural elements, and the introduction of definitions of irregular structures and special design requirements associated with these irregularities. A new requirement for direction of loading is introduced, along with requirements for elements common to more than one lateral load resisting system. The effects of displacements are emphasized throughout the document, and revised provisions for drift limits are proposed. Revisions to the importance factor that integrate it into the proposed revised format for Part 4, Structural design, of the NBCC are given. Background information is presented.Key words: load path importance factor, irregular structures, direction of loading, special requirements, drift limits.

scholarly journals Multiobjective Design Optimization of Grillage Systems according to LRFD-AISC

2011 ◽  
Vol 2011 ◽  
pp. 1-24 ◽  
Author(s):  
Tugrul Talaslioglu
Keyword(s):  
Multiobjective Optimization ◽  
Design Optimization ◽  
Optimization Algorithms ◽  
Grid Structure ◽  
American Institute ◽  
Design Constraints ◽  
Factor Design ◽  
Computational Procedures ◽  
Load And Resistance Factor ◽  
Multiobjective Design

Both the entire weight and joint displacements of grid structures are minimized at the same time in this study. Four multiobjective optimization algorithms, NSGAII, SPEAII, PESAII, and AbYSS are employed to perform computational procedures related to optimization processes. The design constraints related to serviceability and ultimate strength of grid structure are implemented from Load and Resistance Factor Design-American Institute of Steel Constructions (LRFD-AISC Ver.13). Hence, while the computational performances of these four optimization algorithms are compared using different combinations of optimizer-related parameters, the various strengths of grid members are also evaluated. For this purpose, multiobjective optimization algorithms (MOAs) employed are applied to the design optimization of three application examples and achieved to generate various optimal designations using different combinations of optimizer-related parameters. According to assessment of these optimal designations considering various quality indicators, IGD, HV, and spread, AbYSSS shows a better performance comparatively to the other three proposed MOAs, NSGAII, SPEAII, and PESAII.

scholarly journals The new 2005 AISC specification

2007 ◽  
Vol 60 (2) ◽  
pp. 241-250
Author(s):  
Roberto T. Leon
Keyword(s):  
Structural Steel ◽  
Resistance Factor ◽  
Practical Significance ◽  
Steel Buildings ◽  
American Institute ◽  
Framed Structures ◽  
Composite Columns ◽  
Factor Design ◽  
Load And Resistance Factor ◽  
Hollow Structural Sections

In late 2005, the American Institute of Steel Construction issued its most recent Specification for Structural Steel Buildings (ANSI/AISC 360-05). This specification includes updated design provisions in both allowable strength design (ASD) and load and resistance factor design methods (LRFD), and incorporates the design provisions for hollow structural sections and single angles. Amongst the major changes are a complete revamping of the methodologies for assessing stability of framed structures, new provisions for composite columns and updated material requirements. This paper will describe the changes and highlight those of practical significance.

Structural Integrity for Nuclear Power Plant Against Excessive Load on Design Extension Condition

2013 ◽  
Author(s):  
Daigo Watanabe ◽  
Kiminobu Hojo
Keyword(s):  
Nuclear Power ◽  
Structural Integrity ◽  
Safety Factors ◽  
Design Code ◽  
Acceptance Criteria ◽  
Integrity Assessment ◽  
Current Design ◽  
Factor Design ◽  
Excessive Load ◽  
Load And Resistance Factor

This paper introduces an example of structural integrity evaluation for Light Water Reactor (LWR) against excessive loads on the Design Extension Condition (DEC). In order to assess the design acceptance level of DEC, three acceptance criteria which are the stress basis limit of the current design code, the strain basis limit of the current design code and the strain basis limit by using Load and Resistance Factor Design (LRFD) method were applied. As a result the allowable stress was increased by changing the acceptance criteria from the stress basis limit to the strain basis limit. It is shown that the practical margin of the LWR’s components still keeps even on DEC by introducing an appropriate criterion for integrity assessment and safety factors.

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