scholarly journals Seismic retrofit of steel frame structures

2020 ◽  
Vol 15 (2) ◽  
pp. 106-117
Author(s):  
Magdy Ismail

Abstract:Moment resisting frames are considered as an effective seismic force resisting system that is used for steel structures. Some of these structures that were built in high seismic hazard zones were designed according to old strength-based design codes. Currently, these structures do not meet the requirements of the new seismic codes. Therefore, the seismic retrofit of these structures is mandatory and cannot be overlooked. Steel braces and concrete-steel composite elements are common solutions for enhancing the seismic behavior of existing steel frame structures. This paper presents a numerical study that evaluates different possible techniques for the seismic retrofit of existing steel moment-resisting frame structures. The study investigates the performance of three multi-story buildings with different heights that are located in a high seismic hazard zone. Three retrofit techniques were introduced including; 1) X-Steel braces, 2) buckling restrained composite braces, and 3) composite concrete-steel plate shear walls. The seismic performance enhancement of the studied structures was evaluated in terms of the structure’s fundamental period, maximum inter-story drift and maximum base shear-to-weight ratios. Moreover, the cost of retrofitting material was estimated for each technique and they were compared to select the retrofit technique with the least constitutive material cost.

1994 ◽  
Vol 3 (3) ◽  
pp. 163-181 ◽  
Author(s):  
Hiroyuki Fuyama ◽  
Helmut Krawinkler ◽  
Kincho H. Law

2018 ◽  
Vol 230 ◽  
pp. 02036 ◽  
Author(s):  
Alexey Vasilchenko ◽  
Yuriy Otrosh ◽  
Nikolay Adamenko ◽  
Evgeny Doronin ◽  
Andrey Kovalov

The problem of estimation of fire resistance of steel frame structures with intumescent coatings is considered. It implies that both physical properties of a covering (its thickness and structure) and mechanical properties of a metal structure change critically at heating. All above changes should be considered to maintain the standard values of fire resistance of a construction at calculation. Usually, known technical characteristics of fire resistance of intumescent coverings are used for estimation of fire resistance of steel structures with intumescent coverings. Importance of taking into account the influence of strength loss time at heating of a steel structure on calculation of fire resistance limit of system “intumescent fireproof coating steel structure” is shown in the article. On an example of calculation of heating time to the critical temperature of steel columns and beams protected by intumescent coating, it is shown that own heating time of steel structures before they lose strength makes 10 to 16 % from a settlement limit of fire resistance. This fact should be considered at the forecast of fire resistance of steel frame structures with intumescent coatings.


2010 ◽  
Vol 16 (1) ◽  
pp. 103-121 ◽  
Author(s):  
Valentinas Jankovski ◽  
Juozas Atkočiūnas

The improved mathematical model of steel frame structures’ design is created. The loading is simple, and plastic strains are evaluated. Energy principles of deformable body mechanics and mathematical programming theory are employed. Equilibrium finite elements with interpolation functions of internal forces are used for discretization. The elements are designed using HE, IPE, RHS steel profile assortments and considering dispersion of geometrical characteristics of profile assortment sets. Optimal design of steel structures is realized by using the experimental tool system JWM SAOSYS Toolbox v0.42, which was created by the authors in MATLAB environment. SAOSYS architecture operates with object‐oriented finite elements pseudo‐polymorphously. The possibilities of this system are demonstrated by considering a numerical example of optimal design of industrial building frame with strength and stiffness constraints. The assumption of small displacements is adopted for computations. Santrauka Pasitelkus deformuojamo kūno mechanikos energinius principus ir matematinio programavimo teorija, sudarytas minimalaus tūrio strypiniu plieniniu konstrukciju, patyrusiu ir plastines deformacijas, projektavimo nuo vienkartes apkrovos uždavinio patobulintas matematinis modelis. Diskretizacijai naudojami pusiausvirieji baigtiniai elementai su iražu interpo‐liavimo funkcijomis. Elementai projektuojami iš sortimentiniu HE, IPE, RHS plieniniu profiliuočiu, atsižvelgiant i profi‐liuočiu aibiu geometriniu charakteristiku sklaida sortimentuose. Optimalus plieniniu konstrukciju projektavimas realizuojamas autoriu MATLAB aplinkoje sukurta eksperimentine sistema JWM SAOSYS Toolbox v0.42. SAOSYS architektūra pseudopolimorfiškai operuoja objektiškai orientuotais baigtiniais elementais. Sistemos SAOSYS galimybes atskleidžiamos pramoninio pastato remo optimalaus projektavimo su stiprumo ir standumo apribojimais pavyzdžiu. Skaičiuota atsižvelgus i mažu poslinkiu prielaidas.


2021 ◽  
Vol 16 (1) ◽  
pp. 176
Author(s):  
Magdy Ismail ◽  
Hossam El-Sokkary

1998 ◽  
Vol 14 (4) ◽  
pp. 597-627 ◽  
Author(s):  
Aiman Biddah ◽  
Arthur C. Heidebrecht

A large number of low and medium-rise buildings have moment-resisting steel frames as the primary lateral load resisting system. This type of structural system has been considered to be one of the most effective means for resisting strong seismic ground motions. This paper presents the results of an investigation into the performance which can be expected when code designed ductile moment-resisting steel frame buildings having ductile connections, designed for different seismic hazard levels, are subjected to excitation by strong seismic ground motions. Design variations at different seismic hazard levels include three design philosophies, namely strong-column weak-beam, weak-column strong-beam and strong-column weak panel zone. The analytical model used in the study takes into account both connection flexibility and panel zone shear deformation. Results show that the performance arising from a specific design philosophy may be acceptable in one seismic hazard region, while being unacceptable in a region having a different seismic hazard level.


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