3D design of steel structures with considering nonlinear base shear distribution and seismic energy

Structures ◽  
2022 ◽  
Vol 37 ◽  
pp. 82-94
Author(s):  
Masoud Ghamari ◽  
Mohammad Shooshtari ◽  
Hossein Homaei
Author(s):  
Jiří Protivínský ◽  
Martin Krejsa

Abstract For structural design of steel structures under seismic action there are two possible approaches of global analysis. In global analysis we can consider the structure to behave in linear elastic way or in post-elastic way with developing of plastic hinges during seismic situation. The second method is based on principle of seismic energy transformation into thermal energy. Both design methods are defined in Eurocodes but the post-elastic way is only rarely used because of design complexity. Application of this design method is presented in the entry on an example of a steam power plant boiler structure.


2020 ◽  
Vol 10 (10) ◽  
pp. 3403 ◽  
Author(s):  
Masoud Dadkhah ◽  
Reza Kamgar ◽  
Heisam Heidarzadeh ◽  
Anna Jakubczyk-Gałczyńska ◽  
Robert Jankowski

In this paper, parameters of the tuned mass dampers are optimized to improve the performance level of steel structures during earthquakes. In this regard, a six-story steel frame is modeled using a concentrated plasticity method. Then, the optimum parameters of the Tuned Mass Damper (TMD) are determined by minimizing the maximum drift ratio of the stories. The performance level of the structure is also forced to be located in a safety zone. The incremental dynamic analysis is used to analyze the structural behavior under the influence of the artificial, near- and far-field earthquakes. The results of the investigation clearly show that the optimization of the TMD parameters, based on minimizing the drift ratio, reduces the structural displacement, and improves the seismic behavior of the structure based on Federal Emergency Management Agency (FEMA-356). Moreover, the values of base shear have been decreased for all studied records with peak ground acceleration smaller or equal to 0.5 g.


2017 ◽  
Vol 8 (1) ◽  
pp. 2-24
Author(s):  
Sayed Behzad Talaeitaba ◽  
Hamed Esmaeili ◽  
Mohammad Ebrahim Torki

Purpose Steel shear walls have recently received exclusive remark. Respective of most building code requirements, design of shear wall vertical boundary elements (VBEs) and local boundary elements (LBEs) against web yielding triggers exaggerated stiffness. The extent of stiffness reduction effects in boundary elements thus calls for more exhaustive investigation. The paper aims to discuss these issues. Design/methodology/approach To this end, FEM-based push-over curves demonstrating base shear vs roof displacement, and von Mises plastic strains were scrutinized in half-scale and full-size models. Analyses were in perfect conformity with experimental data. Findings With reference to the AISC requirement, up to 35 percent decrease in the VBE moments of inertia could be imparted in higher levels without the ultimate load capacity nor displacement to failure being reduced. Also considered was open shear walls with reduced or minimum-design LBEs, the latter being used in continuous or abridged form. LBEs could be used with a moment of inertia 80 percent smaller than required if only used in a continuous form. The effect due to opening geometry was negligible on loading capacity but distinguished on the post-yielding buckling-induced softening. Practical implications Light-weight design of low- to medium-level steel structures against earthquake loads. Originality/value With respect to continuous walls, the results are more comprehensive than those existing in the literature in that they combine the effects due to scale and orientation (horizontal or vertical) of boundary elements. The results for open shear walls are not only comprehensive but also original in a sense that they account for the influences induced by the opening type (door or window), orientation (horizontal or vertical), and design (full-length or abridged) of boundary elements, in reduced form, on the lateral stiffness of the frame.


2016 ◽  
Vol 6 (2) ◽  
pp. 25-32
Author(s):  
Corina - Ana Moldovan

Abstract The contribution presents a set of seismic analyses of multi - storey steel structures with semi-rigid beam column connections acted upon by seismic actions. Semi-rigidity of the structures beam to column connections is conferred by two types of beam to column connections: top and seat and web angle (TSW) and end-plate (EP) joints. Computed numerical results are associated to two classes (static and kinematic) of seismic behaviour parameters expressing the two contradictory effects of semi-rigidity. On one hand, the lateral flexibility induces larger lateral displacements while, on the other hand, it attracts smaller base shear seismic forces. Also, the constitutive relation M − θr induced into semi- rigid beam column connections by seismic actions is presented. The results are presented in their numerical form and in a comparative graphical manner allowing for relevant comments and conclusions


2020 ◽  
Vol 8 (6) ◽  
pp. 2879-2885

Structural steel has many advantages over other construction materials by its high strength and ductility. It has a higher strength to cost ratio in tension and a slightly lower strength to cost ratio in compression when compared with concrete. This paper is intended to evaluate the beam column rolled and cold formed steel connection experimentally by moment resistant connection such as stiffened, un stiffened and splices connection. At the present, in most of the countries, the use of light gauge cold formed steel section has been developed for economical and best seismic performance by different shape of cross sectional area and various types of connections are used. These results to study the seismic performance of cold form steel sections area using various moment resistance connections. Finally the report result the splice connection has best moment resistance connection, seismic resistant of structures, load carrying capacity is high and minimum weight compare with other types of connections. The splice connection has load carrying capacity is high, so we can reduced the size of section and prevent the base shear due to reduced the weight of structures.


2018 ◽  
Vol 7 (2.29) ◽  
pp. 955
Author(s):  
Mohammed Ziauddin Patowary ◽  
Abdul Kadir Marsono

Due to the urbanization multi-story building with underground story for parking space and storage are very common in practice. Now a day, seismic energy dissipating devices are being used for various types of structures and located in basements which are difficult to maintain.  The main objective is to evaluate the effectiveness of horizontal dampers in the ground floor level of the multi-story building above basement. Among different types of dampers, visco-elastic [VE] dampers are used for this numerical study. Comparing with other types of passive energy dissipating devices, visco-elastic [VE] dampers are considered most suitable. For the better understanding of the effectiveness of horizontal dampers, stiff foundation system is considered thus soil-structure interaction is omitted. In this numerical study, seismic response of different hypothetical structures analyzed having different underground stories and horizontal dampers only in the ground level. Modeling and analysis of the structures and installation of the dampers are done by using finite element modeling software [ETABS]. Time history analysis was used to simulate the response of the structures. Sabah earthquake [05/June/2015] with the PGA of 0.126g was used for the time history analysis. Different dynamics parameters such as natural time period, displacement, base shear and inter-story drift were evaluated. Changes in the results among the structures demonstrated the efficiency of horizontal dampers. Optimum locations of the horizontal dampers were also revealed in this study in the basis of the analysis results.  


2020 ◽  
Vol 18 (5) ◽  
pp. 1037-1052
Author(s):  
Tanuja Singh ◽  
Megha Kalra ◽  
Anil Kumar Misra

Purpose The paper aims to focus on adjacent buildings response, equipped with damper, to analyze the vibration reduction in the nearby buildings. The nearby buildings were also equipped with dampers. The occurrence of adjacent buildings with adequate or inadequate space in between is a common phenomenon. However, many a times not much attention is paid to provide or check gap adequacy or to connect the two buildings suitably to avoid pounding of two structures on each other. This study emphasizes the utility of providing a damper in between two adjacent buildings for better performance. Design/methodology/approach The two steel structures taken for study are prototype of two structures normally found in industrial structure such as power plant, where in one of boiler structure is often tall and braced and short structure of turbine building which is moment resistant, modeled in SAP. There could be similar such structures which are often connected to a platform or a walkway with a sliding end, so as not to transfer horizontal force to other structures. If the advantage of stiffness of tall braced structure is taken into account, shorter structure can be suitably connected to braced structure to transfer forces during seismic cases under nonlinear conditions, thereby avoiding pounding (incase gap is too less), reducing response and thus optimizing the section sizes. The structures were subjected to El Centro earthquake, to simulate MCE (which could be the other site TH scaled up as desired for real site PGA), and damper location and parameters were varied to find optimum value which offers reduced base shear, reduced top floor displacement and minimum inter story drift and highest energy absorption by fluid viscous dampers. Findings The findings show that taller structures, which are braced, have more stiffness; the effect of damper is more pronounced in reducing displacement of shorter moment resistant structure to the tune of 60%, with suitably defined Cd value which is found to be 600 KNs/m for the present study. Thus, advantage of stiffener structure is taken to leverage and reduce the displacement of shorter moment resistant structure in reducing its displacement under nonlinear conditions of seismic case. Originality/value This work shows the original findings, of the adjacent buildings response, equipped with damper, to analyze the vibration reduction on other buildings which were planned to be constructed nearby.


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.


2021 ◽  
Author(s):  
Shubam Sharma ◽  
Aditya Kumar Tiwary

Abstract Numerous studies were contemplated on the structures with distinctive structural configuration and ample amount of work is currently being performed through the investigation of the response of individual behavior of shear walls and bracings by varying configurations and their material properties. Seismic design philosophies had mentioned firmly that a structure must accomplish Life Safety (LS) and Performance Level (PL) for both reinforced concrete and steel structures. This study is anchored on prevailing lateral load resisting system which is virtuous but not adequate to retain vigorous ground motion or acceleration. To overwhelm this problem, an attempt was made to familiarize a new lateral load resisting system formulated by the amalgamation of two different existing lateral load resisting systems, specifically shear walls and bracings. The hybrid structural system embraces two distinctive lateral load resisting techniques, shear walls, and bracings for moment-resisting frame. A numerical finite element study was carried out by the linear dynamic method on the response of structure subjected to seismic condition and an optimal configuration of the different structural patterns is assured by using numerous possible patterns of a hybrid structural system using finite element-based software. The criteria contemplated for study including time period, base shear, overturning moment, story drift ratio, and story displacement are compared with different models and the optimal structure is concluded based upon the recital. The comparative results revealed that there is a reduction noticed in the fundamental time period, and story displacement, where as there is negligible increment in base shear and overturning moment for the hybrid structural system as compared to other configurated models.


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