scholarly journals Dynamic properties of steel structures under different construction stages, ambient temperature and live load

2021 ◽  
Vol 20 (1) ◽  
pp. 163-177
Author(s):  
Işıl Sanrı Karapınar ◽  
◽  
Fuat Aras ◽  
Keyword(s):  
Ambient Temperature ◽  
Numerical Models ◽  
Dynamic Properties ◽  
Steel Structures ◽  
Live Load ◽  
Steel Buildings ◽  
Partition Walls ◽  
Service Load ◽  
Building Behavior ◽  
Widespread Interest

Operational modal analysis (OMA), assessing the effect of environmental conditions on the structures has been attracting widespread interest and its results have been used for the validation of numerical models. This paper aims to validate the application of OMA on steel buildings to investigate their dynamic behavior during and after their construction. In this context, the construction stages of a steel building were monitored. With the completion of the construction, the dynamic tests were applied at different times to identify the changes in the modal characteristics of the building with respect to the temperature and service loads. Finally, the analytical model of the building was performed and the building’s dynamic properties were determined numerically. As a result, the experimentally obtained dynamic properties for the completed building were compared to those derived from numerical analysis. The results underlined the importance of slab construction for the formation of building behavior in the construction stages. Besides the effects of ambient temperature and service load on the dynamic properties of steel buildings were revealed. Finally, the lack of partition walls in the numerical model has been grasped as the main reason behind the differences between the experimentally and numerically obtained dynamic properties.

Performance of steel buildings and nonstructural elements during the 27 February 2010 Maule (Chile) Earthquake

2013 ◽  
Vol 40 (8) ◽  
pp. 722-734 ◽  
Author(s):  
Murat Saatcioglu ◽  
Robert Tremblay ◽  
Denis Mitchell ◽  
Ahmed Ghobarah ◽  
Dan Palermo ◽  
...  
Keyword(s):  
Structural Steel ◽  
Steel Structures ◽  
Steel Buildings ◽  
Industrial Facilities ◽  
Architectural Features ◽  
Partition Walls ◽  
Chile Earthquake ◽  
Maule Earthquake ◽  
Observed Damage ◽  
2010 Maule Earthquake

This paper presents performance of steel buildings and nonstructural elements during the 27 February 2010 Maule Earthquake in Chile. Structural steel buildings are not common in Chile, due to the relatively high cost of material. The majority of damage to steel structures was observed in industrial facilities. In general, the structural steel buildings performed well. Limited damage was observed in some of the older buildings. Extensive damage was sustained by nonstructural elements, including masonry infill walls, suspended ceilings, partition walls, and architectural features. Brick masonry partition walls, commonly used in Chilean buildings, suffered damage when used in frame buildings with little drift control. The paper presents a summary of observed damage and a comparison of Chilean and Canadian design practices for steel buildings, with lessons drawn from observed structural performance.

Seismic Performance Assessment of Existing Steel Buildings: A Case Study

2018 ◽  
Vol 763 ◽  
pp. 1067-1076 ◽  
Author(s):  
Luigi di Sarno ◽  
Fabrizio Paolacci ◽  
Anastasios G. Sextos
Keyword(s):  
Numerical Study ◽  
Central Italy ◽  
Steel Structures ◽  
Eurocode 8 ◽  
Building Structures ◽  
Steel Buildings ◽  
Seismic Performance Assessment ◽  
Masonry Infills ◽  
Main Shocks

Numerous existing steel framed buildings located in earthquake prone regions world-wide were designed without seismic provisions. Slender beam-columns, as well as non-ductile beam-to-column connections have been employed for multi-storey moment-resisting frames (MRFs) built before the 80’s. Thus, widespread damage due to brittle failure has been commonly observed in the past earthquakes for steel MRFs. A recent post-earthquake survey carried out in the aftermath of the 2016-2017 Central Italy seismic swarm has pointed out that steel structures may survive the shaking caused by several main-shocks and strong aftershocks without collapsing. Inevitably, significant lateral deformations are experienced, and, in turn, non-structural components are severely damaged thus inhibiting the use of the steel building structures. The present papers illustrates the outcomes of a recent preliminary numerical study carried out for the case of a steel MRF building located in Amatrice, Central Italy, which experienced a series of ground motion excitations suffering significant damage to the masonry infills without collapsing. A refined numerical model of the sample structure has been developed on the basis of the data collected on site. Given the lack of design drawings, the structure has been re-designed in compliance with the Italian regulations imposed at the time of construction employing the allowable stress method. The earthquake performance of the case study MRF has been then investigated through advanced nonlinear dynamic analyses and its structural performance has been evaluated according to Eurocode 8-Part 3 for existing buildings. The reliability of the codified approaches has been evaluated and possible improvements emphasized.

scholarly journals Multiobjective optimal design of reinforced concrete frames using two metaheuristic algorithms

2021 ◽  
Vol 9 (4B) ◽  
Author(s):  
Mehdi Babaei ◽  
◽  
Masoud Mollayi ◽  
Keyword(s):  
Reinforced Concrete ◽  
Optimal Design ◽  
Optimization Problem ◽  
Numerical Models ◽  
Steel Structures ◽  
Metaheuristic Algorithms ◽  
Rc Structures ◽  
Weighted Sum Method ◽  
Rc Frames ◽  
Single Objective

Genetic algorithm (GA) and differential evolution (DE) are metaheuristic algorithms that have shown a favorable performance in the optimization of complex problems. In recent years, only GA has been widely used for single-objective optimal design of reinforced concrete (RC) structures; however, it has been applied for multiobjective optimization of steel structures. In this article, the total structural cost and the roof displacement are considered as objective functions for the optimal design of the RC frames. Using the weighted sum method (WSM) approach, the two-objective optimization problem is converted to a single-objective optimization problem. The size of the beams and columns are considered as design variables, and the design requirements of the ACI-318 are employed as constraints. Five numerical models are studied to test the efficiency of the GA and DE algorithms. Pareto front curves are obtained for the building models using both algorithms. The detailed results show the accuracy and convergence speed of the algorithms.

scholarly journals Partial factors for cross-section resistance of elements in steel structures

2013 ◽  
Vol 12 (2) ◽  
pp. 213-220
Author(s):  
Marian Giżejowski ◽  
Zbigniew Stachura
Keyword(s):  
Cross Section ◽  
Steel Structures ◽  
Partial Cross Section ◽  
Live Load ◽  
Practical Application ◽  
Limit States ◽  
Resistance Factors ◽  
Safety Requirements ◽  
Permanent Load ◽  
Load Component

Issues related to safety requirements for steel elements subjected to different stress resultants in reference to limit states design philosophy according to Structural Eurocodes PN-EN and national codes PN-B are dealt with in the paper. The calibration of partial cross-section resistance factors is discussed on the basis of elements of steel floor structures where the permanent load component and the live load component of variable actions are the only components of load combinations. Final conclusions for their practical application in the codification process are formulated and values of partial factors for cross section resistance are proposed.

scholarly journals Comparative Analysis of the Energy Dissipation of Steel Buildings with Concentric and Eccentric Braces

2015 ◽  
Vol 9 (1) ◽  
pp. 295-307 ◽  
Author(s):  
Edelis del V. Marquez A. ◽  
William Lobo-Q ◽  
Juan C. Vielma
Keyword(s):  
Energy Dissipation ◽  
Shear Failure ◽  
Numerical Models ◽  
Deformation Energy ◽  
Seismic Zone ◽  
Deformation Capacity ◽  
Building Structures ◽  
Steel Buildings ◽  
High Deformation ◽  
Energy Dissipation Capacity

A comparative study has been done to analyze the behavior of regular steel building structures of 4, 6, 8 and 10 stories, located in seismic zone 5 and soil type S1. The structures were upgraded with different brace configurations according to current Venezuelan codes. A total number of 24 numerical models were analyzed considering non-linear static and incremental dynamic analysis (IDA). The buildings were initially designed as moment resisting frames, and upgraded with six different bracing configurations: concentric braces in “X” and inverted “V”; eccentric braces inverted "V" with horizontal links, inverted “Y” and “X” with vertical links. Short length links were used to ensure a shear failure. The used methodology is based on obtaining the capacity, IDA curves, and bilinear approximations of these curves that allow the determination of yield and ultimate capacity points, in order to estimate important parameters of seismic response: overstrength and ductility; and considering these areas under the curves to estimate elastic deformation energy, energy dissipated by hysteretic damping and equivalent damping. According to the results, the cases with no brace enhancement showed the lowest lateral strength and lateral stiffness and high deformation capacity. On the other hand, the concentric bracing cases, resulted with the highest stiffness and strength and the lowest deformation capacity, therefore they have low ductility and energy dissipation capacity under seismic loading. Structures with links showed intermediate stiffness and strengths, resulting in the best performance in terms of ductility and energy dissipation capacity. The present study provides a better understanding of the benefits of eccentrically braced systems.

New Zealand Research Applications of, and Developments in, Low Damage Technology for Steel Structures

2018 ◽  
Vol 763 ◽  
pp. 3-10 ◽  
Author(s):  
Gregory A. MacRae ◽  
George Charles Clifton ◽  
Michel Bruneau
Keyword(s):  
New Zealand ◽  
Large Scale ◽  
Base Isolation ◽  
Steel Structures ◽  
Small Towns ◽  
Steel Buildings ◽  
Construction Methods ◽  
Steel Framing ◽  
Friction Pendulum ◽  
Building Demolition

Over the past few years, the South Island of New Zealand has been subject to significant sequences of earthquake shaking. In particular, 2010-2011 events affected the city of Christchurch resulting in large scale demolition of buildings. Also, the recent and continuing 11/2016 events caused severe damage in the countryside, in small towns, and moderate damage further afield. This paper describes “low damage construction” methods being used in NZ, and especially in the Christchurch rebuild, to limit the possibility of building demolition in future large seismic events. The buildings used in the Christchurch rebuild are generally supported by structural steel framing. These steel buildings include BRB systems, EBF systems with replaceable active links, rocking systems, base isolation using friction pendulum systems and/or lead-rubber dissipaters, RBS beams, lead extrusion dissipaters, yielding flexural dissipaters, and friction connections. Concerns about a number of currently used systems are discussed.

Assembling of Parallel Programs for Large Scale Numerical Modeling

2012 ◽  
pp. 497-511
Author(s):  
V.E. Malyshkin
Keyword(s):  
Large Scale ◽  
Parallel Implementation ◽  
Numerical Models ◽  
Dynamic Properties ◽  
Parallel Program ◽  
Particle In Cell ◽  
Modular Programming ◽  
Rectangular Mesh ◽  
Assembly Technology ◽  
Main Ideas

The main ideas of the Assembly Technology (AT) in its application to parallel implementation of large scale realistic numerical models on a rectangular mesh are considered and demonstrated by the parallelization (fragmentation) of the Particle-In-Cell method (PIC) application to solution of the problem of energy exchange in plasma cloud. The implementation of the numerical models with the assembly technology is based on the construction of a fragmented parallel program. Assembling of a numerical simulation program under AT provides automatically different useful dynamic properties of the target program including dynamic load balance on the basis of the fragments migration from overloaded into underloaded processor elements of a multicomputer. Parallel program assembling approach also can be considered as combination and adaptation for parallel programming of the well known modular programming and domain decomposition techniques and supported by the system software for fragmented programs assembling.

Steel Buildings' Seismic and Interaction Behavior, Under Different Shapes of Tunnel Drilling

2016 ◽  
Vol 7 (2) ◽  
pp. 1-23 ◽  
Author(s):  
Arash Rostami ◽  
Hamid Alielahi ◽  
Abdoreza Sarvghad Moghadam ◽  
Mahmood Hosseini
Keyword(s):  
Urban Areas ◽  
Steel Structures ◽  
Urban Environments ◽  
Steel Buildings ◽  
Underground Structures ◽  
Residential Areas ◽  
Earthquake Records ◽  
Structural Responses ◽  
Different Shapes ◽  
And Behavior

Development of civil engineering science has introduced tunneling as an important option in reducing the traffic volume of urban environments. Digging tunnels, in every depth, causes changes in the surface ground structure; tunneling in urban areas, especially when has passed through the residential areas has its own particular importance; therefore, having knowledge about tunnels' behavior and effects of diggings is necessary, and in order to prevent unpredictable damages to the structures is one of the requirements of designing. The performance and behavior of underground structures have been studied by many researchers, but the effects of tunneling on earthquake records and its effects on structures above the ground has taken less attention. This study will try to check earthquake record changes and their impact on steel structures located on top part of the tunnels, and has done this issue with digging some circular tunnels. The results indicate that, tunneling alters the earthquake records and also has affections on structural responses.

Mechanical Properties Prediction for Cold-formed Steel Angle Connection with Various Flange Cleat Thickness

2015 ◽  
Vol 74 (4) ◽  
Author(s):  
Yeong Huei Lee ◽  
Cher Siang Tan ◽  
Shahrin Mohammad ◽  
Yee Ling Lee
Keyword(s):  
Mechanical Properties ◽  
Numerical Models ◽  
Steel Structures ◽  
Rotational Stiffness ◽  
Steel Angle ◽  
Cold Formed Steel ◽  
Mechanical Properties Prediction ◽  
Thin Walled ◽  
Angle Connection ◽  
Hot Rolled

Connection is an important element in structural steelwork construction. Eurocode does not provide adequate design information for mechanical properties prediction of top-seat flange cleat connection, especially for thin-walled cold-formed steel structures. Adopting hot-rolled design with neglecting thin-walled behaviour could lead to unsafe or uneconomic design. This research aims to provide accurate mechanical properties prediction for bolted top-seat flange cleat connection in cold-formed steel structures. The scope of work focuses on the effect of various thickness of the flange cleat to the rotational stiffness and strength behaviour of a beam-to-column connection. Experimentally verified and validated finite element modelling technique is applied in the parametric investigation. Two categories of flange cleat thickness, ranged from 2 mm to 40 mm are studied. From the developed numerical models, it is observed that Eurocode has overestimated the initial rotational stiffness prediction, calculated with component method. The over-estimation would influence the overall stiffness of structures and force distribution within the components. As a conclusion, a set of newly proposed accurate predictions for initial rotational stiffness and strength of cold-formed steel top-seat flange cleat connection, with the influence of the thickness of flange cleat is presented.

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