Steel Structure Model Research Articles

Dynamic Response of Steel Structure with Bracings and Translational Tuned Mass Dampers

In this work the dynamic response of steel structure with Bracings and Translational Tuned Mass Damper (TTMD) are studied. TTMD is a device that consists of a mass which is connected to the structure by means of a spring and a damper. The mass is tuned to vibrate at the different frequency as the structure, which allows it to cancel out the vibrations of the structure. Bracings are added to the structure to provide additional stiffness and strength. G+5, G+15 and G+25 Storeyed steel structure models with the different combinations of bracings and TTMD are considered in this study. Following which the FE Analysis involving the modal, equivalent static and response spectrum analysis are performed and results are obtained in terms of Time period, Base Shear, storey displacement and Storey drift all are discussed.

Surrogate models for seismic and pushover response prediction of steel special moment resisting frames

For structural engineers, existing surrogate models of buildings present challenges due to inadequate datasets, exclusion of significant input variables impacting nonlinear building response, and failure to consider uncertainties associated with input parameters. Moreover, there are no surrogate models for the prediction of both pushover and nonlinear time history analysis (NLTHA) outputs. To overcome these challenges, the present study proposes a novel framework for surrogate modelling of steel structures, considering crucial structural factors impacting engineering demand parameters (EDPs). The first phase involves the development of a process by which 30,000 random steel special moment resisting frames (SMRFs) for low to high-rise buildings are generated, considering the material and geometrical uncertainties embedded in the design of structures. In the second phase, a surrogate model is developed to predict the seismic EDPs of SMRFs when exposed to various earthquake levels. This is accomplished by leveraging the results obtained from phase one. Moreover, separate surrogate models are developed for the prediction of SMRFs’ essential pushover parameters. Various machine learning (ML) methods are examined, and the outcomes are presented as user-friendly GUI tools. The findings highlighted the substantial influence of pushover parameters as well as beams and columns’ plastic hinges properties on the prediction of NLTHA, factors that have been overlooked in prior studies. Moreover, CatBoost has been acknowledged as the superior ML technique for predicting both pushover and NLTHA parameters for all buildings. This framework offers engineers the ability to estimate building responses without the necessity of conducting NLTHA, pushover, or even modal analysis which is computationally intensive.

Vibration IOT Control Algorithm for Steel Structures of Concrete Buildings with Elastic Boundary Constraints

Abstract Because of the influence of steel structure’s elastic properties in concrete buildings, the traditional vibration Internet of Things (IOT) control algorithm of steel structures has the problem of low control efficiency. Based on the research subject of concrete buildings, a corresponding steel structure model is established, and the corresponding vibration control standard is determined according to the characteristics of the model. In this model, the boundary elastic constraints of the steel structure are set according to its structural characteristics, and the vibration characteristics of the steel structure are analyzed under the constraints. The external vibration signal is simulated, and the response of the building’s steel structure under different signal excitations is observed. According to the response characteristics of the steel structure, the vibration controller is designed and installed, the real-time vibration signal is input into the controller, and finally the vibration control of steel structure of concrete building is realized. By comparison with the traditional vibration IOT control algorithm, it is concluded that the vibration control method designed by combining vibration frequency and vibration amplitude has smaller error and shorter time cost, that is, the designed vibration IOT control algorithm has more advantages in control efficiency.

The Effect of the Crack‐Stiffness Relationship on the System Response in Columns of an SDOF Steel Structure Model under Harmonic and Earthquake Excitations

The Effect of the Crack‐Stiffness Relationship on the System Response in Columns of an SDOF Steel Structure Model under Harmonic and Earthquake Excitations

Meta databases of steel frame buildings for surrogate modelling and machine learning-based feature importance analysis

Traditionally, nonlinear time history analysis (NLTHA) is used to assess the performance of structures under future hazards which is necessary to develop effective disaster risk management strategies. However, this method is computationally intensive and not suitable for analyzing a large number of structures on a city-wide scale. Surrogate models offer an efficient and reliable alternative and facilitate evaluating the performance of multiple structures under different hazard scenarios. However, creating a comprehensive database for surrogate modelling at the city level presents challenges. To overcome this, the present study proposes meta databases and a general framework for surrogate modelling of steel structures. The dataset includes 30,000 steel moment-resisting frame buildings, representing low-rise, mid-rise and high-rise buildings, with criteria for connections, beams, and columns. Pushover analysis is performed and structural parameters are extracted, and finally, incorporating two different machine learning algorithms, random forest and Shapley additive explanations, sensitivity and explainability analyses of the structural parameters are performed to identify the most significant factors in designing steel moment resisting frames. The framework and databases can be used as a validated source of surrogate modelling of steel frame structures in order for disaster risk management.

Mechanical properties of corner material in cold-formed steel structure: From normal strength to high strength

Cold-forming effect varies from normal strength steel to high strength steel due to the different chemical compositions and mechanical properties of parent materials. To date, research studies on material characterisation of cold–formed steels have been mainly focusing on the normal strength structural steel, while systematic research on high strength structural steel remains scarce. In this paper, an experimental investigation into changes in mechanical properties of high strength steel undergoing various levels of plastic deformation is firstly presented. The test results have been combined with other available high strength steel data, and compared to the normal strength steel data. Of the analysis results indicated, unified predictive equations, modified from Karren’s model in 1967 can predict the strength enhancement behaviours of normal strength and high strength steel, utilising the ultimate-to-yield strength ratio of parent materials fu,f/fy,f and inner radius-to-thickness ratio after cold–forming ri/t. Moreover, the decreases in the Young’s modulus, ultimate strain and elongation at fracture of normal strength and high strength steel after cold-forming can be predicted with no further grouping required. Statistical evaluation results confirm the accuracy of the proposed predictive expressions. This paper extends the scope of the strength enhancement equation in current north American cold-formed steel design code AISI S100–16 to high strength steels with grade up to 960 MPa, and provides key predictive material equations that can be further used in the design or numerical modelling of cold-formed steel structures.

Experimental study on earthquake‐induced pounding between steel structures

AbstractPounding between adjacent structures has been repeatedly observed during major earthquakes. The phenomenon may cause some local damage at the points of interactions, it may also lead to substantial destruction, permanent deformations or total collapse of colliding structures. The effects of earthquake‐induced structural pounding have been studied for more than three decades now. However, most of the studies concerned masonry as well as reinforced concrete structures and investigations on steel structures are very limited. The aim of the present paper is to show the results of the shaking table experimental investigation focused on earthquake‐induced pounding between three models of steel structures in a row. The models were constructed out of four steel columns made from rectangular box section with additional steel skew bracings so as to prevent transverse and torsional vibrations. To obtain different dynamic characteristics of the models, additional plates were added at the top of each tower. Two configurations were investigated. In the first one, two plates were mounted on the external structures and only one plate at the top of the middle tower. In the second configuration, only one plate was mounted at the top of external towers and two plates on the middle structure. Firstly, the free vibration tests were conducted. Then, the steel towers with different in‐between gap sizes were tested under different earthquakes. The results of the study confirm that interactions between insufficiently separated steel structures may significantly influence the structural behaviour during earthquakes. In most of the cases, pounding has resulted in the increase in the peak responses. In some cases, however, it has played a positive role leading to the decrease in the structural response under seismic excitation. Anyway, even if the response is reduced, interactions should be prevented at the design stage of steel structures since they may result in considerable damage at the points of impacts.

Comparative Study of Strengthened Steel Structure Behavior Using Bracing and Shearwall

Multi-storey buildings are very susceptible to lateral forces, so reinforcement is needed to stiffen the building by adding a system of stiffeners to the building structure. In steel building structures, the system of stiffeners bracing and confessor shearwall can provide rigidity and strength by limiting the movement of the structure. In addition, the placement of stiffener systems in the right locations can also increase the rigidity of the building structure. This study aims to compare the effectiveness of structural behavior using a stiffener system based on the value of the fundamental period (T), the base shear force (V), the drift between stories (?x). In this research using a steel structure model that functions as an office building with a height of 10 levels, one variation of the model without stiffeners and four models with stiffeners, with two variations of the position of the stiffeners, namely in the middle and on the edge of the structure. The results of this study indicate that the addition of a stiffener system can increase the rigidity of the structure. The most effective structural model is found in the structural model with stiffeners shearwall the stiffener position in the middle which has a fundamental period value in the X and Y directions of 17.67% and 18.32% is better than the other models. For the base shear force values in the X and Y directions are 0.95% and 0.95% smaller than the other models. The deviation values between floor levels in the X and Y directions are 9.67% and 34.17% better than the other models. Meanwhile, the inefficient structural model is found in the structural model with stiffeners bracing on the edge which has a fundamental period value in the X and Y directions of 8.96% and 9.32% which is no better than the other models. For the base shear force values in the X and Y directions are 18.02% and 18.02% greater than the other models. The deviation values between floor levels in the X and Y directions are 1.69% and 13.15%, not better than the other models. So in this study it can be concluded that the stiffener system with a position in the middle is better than the position on the edge.

Finite element modelling of lattice angle steel structures exposed to wildland fires

Essential civil infrastructure such as transmission line supporting towers and communication base towers that are traditionally formed from lattice angle steel structures are critical global assets, since their development promotes the establishment of electric power supply systems and modern telecommunication networks. Because this infrastructure is commonly located in rural and urban wildland areas, such towers may be prone to wildland fire attack, particularly in the current climate of severe heatwaves and droughts. Accordingly, a comprehensive study of the behaviour and response of lattice angle steel structures under fire loading is needed to assist in structural design to resist fire loading. In this paper, a finite element (FE) model of lattice angle steel structures is constructed using ABAQUS software. Several aspects that include material and geometric non-linearities, load eccentricities on component members, bolted joint slippage, and the use of the explicit dynamic analysis technique for a quasi-static loading procedure, are considered and applied in the FE model. The accuracy and reliability of the FE representation are validated by comparing its predictions with relevant existing experimental results. By incorporating the codified temperature-dependent material properties of structural steel as well as a calibrated load-slip relationship for bolted connections at elevated temperatures, the FE model is extended for performing structural fire analysis. The variations of the steelwork temperatures in wildland fires can be calculated based on representative temperature-time wildland fire curves and is adopted in the fire analysis. By invoking the FE model, an example of lattice angle steel structures is contrived to elucidate the fundamental behaviour of these structures in wildland fires, through both steady and transient state fire analyses. Parametric studies are also undertaken to evaluate the effects of the changes in the wind load direction, bolt pretension and the protection of critical panel sections on the behaviour of lattice structures when exposed to wildland fires.

“Performance assessment of composite steel building with considering plan irregularity before and after Retrofit”- Pushover Analysis”

The performance assessment of the structure under an unexpected earthquake is the key thing to recognize the individual failure of elements of a structure by conducting an inelastic static pushover analysis. If there are multiple earthquakes in any of the year, the performance of structure assessed from linear elastic analysis is not sufficient therefore there is a need of study on non-linear behavior of the structure to provide an extra safety to the structures. The nonlinear dynamic analysis needs lot of data to be given to the generated model in software for studying the behavior of the structure but there is another promising method to overcome the above complexity that is nonlinear static analysis (Pushover analysis) to the assess the behavior of the structure when subjected to multiple earthquakes. For the present study, A G+6 Story ‘L’ Shape plan irregular steel structure (model 1) with floor to floor height as 3 m and 7 bays in ‘X’ & ‘Y’ direction of each 4 m is considered. From Pushover analysis on ‘L’ shape steel structure, it was observed that some of corner columns reached capacity ratio due to excessive stress at beam-column junction and to overcome this, the retrofitting technique was adopted that is consideration of those corners columns as composite columns in the same steel structure (model 2). The plastic hinges formed due to PUSHX for model 1 have reached immediate occupancy performance level to life safety performance level but at 9th iteration, 8 numbers of plastic hinges have been formed in Collapse presentation level hence there might be partial or complete collapse of structure. After retrofitting model 1, the plastic hinges in greater than CP level were formed in different step number so therefore, model 2 sustains more damage before it collapse.

ПАРАМЕТРИЗАЦИЯ ТРЕБОВАНИЙ КОРРОЗИОННОЙ ЗАЩИЩЕННОСТИ СТАЛЬНЫХ КОНСТРУКЦИЙ

Basic provisions are presented of scientific and methodological substantiation of corrosion protectability of steel structures and installations. Priorities have been analyzed of improving existing codes, taking into account scientific achievements and international standards. Tasks have been formulated for increasing competitiveness and resource saving through the use of effective measures of corrosion protection. The study is aimed at parameterization of a mechanism of technical regulation of quality, reliability and safety, approval and application of materials and technologies, procedures, services in the field of corrosion protection at the request of a digital consumer. A process-oriented methodology is proposed aimed at a continuous improvement of development cycles and models of the rational choice of systems of corrosion protection of structures. With that, corrosion protection of structural steel is defined by the level of reliability and required parameters of technical and economic protection. The management structure is defined by the provisions of organization standard in accordance with ISO 12944, SP 28.1330.2017 with regard to corrosion protection of structural steel. The levels have been analyzed of reliability of structures and their protective coatings, with account for the procedures for assessing compliance of quality, monitoring and risk diagnostics based on the limit states method. Parameter compliance is affirmed based on five DMAIC principles related to determination, measurement, analysis, improvement and monitoring technical condition of structures. Examples are presented of statistical estimation of representative samples of corrosion impacts, characteristic values of corrosion resistance and durability of steel structures and their protective coatings. Proposed are methods for functional and time redundancy of corrosion protection assurance. Load testswere carried outof models of steel structures with corrosion damage. The obtained results reveal uncertainty of parameters of corrosion state and allow assessing structural steel survivability with account for acceptable risk. Suggestions for parametric design are recommended for digital transformation of the system of technical and economic regulators of corrosion protectability.

Frame Structure Fault Diagnosis Based on a High-Precision Convolution Neural Network

Structural health monitoring and fault diagnosis are important scientific issues in mechanical engineering, civil engineering, and other disciplines. The basic premise of structural health work is to be able to accurately diagnose the fault in the structure. Therefore, the accurate fault diagnosis of structure can not only ensure the safe operation of mechanical equipment and the safe use of civil construction, but also ensure the safety of people's lives and property. In order to improve the accuracy fault diagnosis of frame structure under noise conditions, the existing Convolutional Neural Network with Training Interference (TICNN) model is improved, and a new convolutional neural network model with strong noise resistance is proposed. In order to verify THE superiority of the proposed improved TICNN in anti-noise, comparative experiments are carried out by using TICNN, One Dimensional Convolution Neural Network (1DCNN) and First Layer Wide Convolution Kernel Deep Convolution Neural Network (WDCNN). The experimental results show that the improved TICNN has the best anti-noise ability. Based on the improved TICNN, the fault diagnosis experiment of a four-story steel structure model is carried out. The experimental results show that the improved TICNN can obtain high diagnostic accuracy under strong noise conditions, which verifies the advantages of the improved TICNN.

Modelling, Test and Practice of Steel Structures

Steel structures have been widely used in civil engineering in recent decades across applications such as large spatial structures, high-rise buildings, and bridges [...]

Levels of Detail of Digital Models of Steel Structures

Levels of Detail of Digital Models of Steel Structures

DETERMINATION OF STRUCTURAL DAMAGE LEVELS BY USING DYNAMIC PARAMETERS

Aim: This study revealed the relationship between the change in dynamic characteristics of structures damaged by exposure to extreme loads such as earthquakes, explosions, and impact and damage levels. Thus, a quick method can be used immediately after the damage has been proposed. Method: The studies consist of two parts, experimental measurements, and numerical solutions. For the analysis, a single degree of freedom, a four-column steel model structure was fabricated, and its free vibrations were recorded with the help of an accelerometer. Three scenarios are defined for the system no damage, medium damage, and heavy damage. Each of these failure scenarios is achieved by changing the boundary conditions of the columns. Results: The acceleration records were processed with the Seismosignal software, and the free vibration periods of the structure were determined for each case. In the numerical part of the study, free vibration periods of undamaged and damaged structures were calculated using the finite element method. Conclusion: It has been shown that the results obtained from the experimental and numerical methods are compatible. With the study, it has been revealed that damaged structures can be evaluated using free vibration periods.

EVALUATION OF THE STABILITY DESIGN METHODS IN STEEL STRUCTURES

Stability for all building systems; Although it is a problem that must be overcome in terms of life safety and building safety, it has special importance, especially for steel structures. The high strength of the steel provides easy access to sufficient bearing capacity with small cross-sections in the carrier system elements. However, while the buckling problem is encountered in the structural element formed with small sections and subjected to axial pressure load, the stability problem is also met when the holistic behavior of the same structural system is examined. For this reason, it is necessary to carry out the design by examining the stability situation based on elements and throughout the system during the design phase. It would be a correct method to consider the factors affecting the stability of the element and the structure with a comprehensive research in the stability design. In this context, international steel regulations and Turkish Steel Regulations (ÇYTYHE-2016) offer design opportunities with two different methods: General Analysis (GA) and Buckling Length (BB) method. There are two different analysis methods to consider the second-order effects of the design methods. These methods are nonlinear geometric analysis (nonlinear) and approximate second-order analysis methods (YIMA). When the presented methods are blended, they form four different design and analysis methods within certain boundary situations. Aim: This study is aimed to compare the four methods within the limits of applicability and to highlight their advantages and disadvantages. Method: Within the scope of the study, a single-story plane steel frame system and an 8-story steel structure model were designed with first-order analysis and stability controls with four different methods, and the results were analyzed. Result: As a result of the study, in terms of clarity and applicability in the calculations, the GA method is different from the BB method; It has been seen that the Nonlinear analysis method is more reliable than YIMA since it can analyze the deformations more realistically. However, in cases where the use of the superposition principle is necessary, the nonlinear analysis method cannot be applied, so the use of the YAMA method is advantageous.

Probabilistic Seismic Assessment of Moment Resisting Steel Buildings Considering Soft-story and Torsional Irregularities

In this study, the fragility curves were developed for three-, five-, and eight-story moment resisting steel frame structures with considering soft story and torsional irregularities during the earthquake mainshock to assess the probabilistic effects of irregularities in plan and height of steel structures. These models were designed according to Iranian seismic codes. 3D analytical models of steel structures were created in the OpenSees software platform and Incremental Dynamic Analysis (IDA) was conducted to plot the IDA curves. The maximum value of inter-story drift was selected as the demand parameter and the capacity is determined according to the HAZUS-MH limit states; and finally, the corresponding fragility curves were developed. The results of the 3D nonlinear dynamic analysis indicated that the damage state of the structure due to soft story irregularity was decreased with increasing stories. On the other hand, the damage caused by torsional irregularity in plan was increased by increasing the height of the structure. For example, in the 3-story structure, soft-story effect on damage probability was more dominant than torsional irregularity.

Experimental analysis of the behaviour of different types of joints in the steel structure model subjected to earthquake loading

The present paper reports the results of the experimental study performed to investigate the behaviour of two different types of joints (destroyed and welded ones) in the model of the steel structure under seismic excitations. The structure was subjected to three earthquakes, namely Kobe, Loma Prieta and Northridge, using the shaking table investigation. The results obtained from the study indicate that there is a significant difference between the behaviour of destroyed joints and welded ones. It was concluded that the destroyed joints experience higher acceleration than the welded joints during different earthquakes.

The axial capacity of a full height rectangular opening castellated steel beam with steel reinforcement stiffeners

The axial capacity of a full height rectangular opening castellated steel beam with steel reinforcement stiffeners is proven to prevent Vierendeel failure mechanism. The effect is an increase in flexural capacity of the structure. Diameter of the steel reinforcement stiffeners is revealed to have an effect on its strength in resisting axial forces occur in the structure. However, size of the diameter is limited to the strength maximum value of the steel flange section in withstanding the moment force. Using optimal design of the castellated steel structure, this research aimed to find out the increase value of the axial capacity. There were two models of steel structures employed in the study, IWF 200x100x5.5x8 and castellated beam 362x100x5.5x8, both were loaded with axial directions. Analyses were conducted using truss and pushover methods. Results of the study showed an increase in both flexural (36.81%) and axial (60.78%) capacities. The increase in the value of structure capacity mainly influenced by the stiffeners shortened the effective length of the structure.

Sensör ve Akıllı Telefon Kayıtları Yardımı ile Yapının Dinamik Karakteristiklerin Belirlenmesi

Çalışma kapsamında, sarsma tablasındaki çelik model yapıya yerleştirilen sensör ve akıllı telefondan elde edilen titreşim değerleri ile MATLAB matematiksel tahmin modeli kullanılarak oluşturulan titreşim değerleri arasındaki uyum oranları karşılaştırılmıştır. Deneysel çalışmada kullanılan çelik model yapı; tek açıklıklı, dört katlı çelik malzemesinden üretilmiştir. Çelik model yapıda bulunan kolon-kiriş bağlantıları rijit, model binanın dört tarafında bulunan temel bağlantıları sarsma tablasına ankastre olacak şekilde montelenmiştir. Deneysel çalışmadan elde edilen titreşim değerleri, sarsma tablasının tabanına ve çelik model yapının tepe noktasına yerleştirilen sensör ve akıllı telefondan elde edilmiştir. Sarsma tablası El-Centro, Loma-Prieta, Kobe ve Sakarya depremlerinin titreşim değerleriyle zorlanmış ve oluşan zorlanmanın yapıda meydana getirdiği titreşimler sensör ve akıllı telefon yardımıyla kaydedilmiştir. Sarsma tablasının tabanında bulunan sensör ve akıllı telefon titreşim değerleri girdi, çelik model yapının tepe noktasında bulunan sensör ve akıllı telefonlar titreşim değerleri sisteme çıktı olarak tanımlanmıştır. Çalışmaların sonucunda deneysel olarak elde edilen girdi-çıktı verileri arasındaki uyumluluk oranları, Matlab programındaki otoregresif ARX ve otoregresif hareketli ortalamalar ARMAX modelinde bulunan tahmin-öngörü ile üretilen girdi-çıktı arasındaki uyumluluk oranları karşılaştırılmıştır.