bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and numerical investigation of reduced web section connections in fire
Authors: Oday Yabari , Mika Alanen , Mikko Malaska , Katherine A. Cashell 
Published: September 2023

AbstractThis paper presents the details and analysis of a fire test conducted on a reduced web section (RWS) connection for steel framed construction. The test was completed in the fire laboratory at Tampere University in order to assess how these connections, usually selected and designed for their seismic performance, behave under fire conditions. RWS connections were first devised for fixed joints in steel framed buildings, with a view to moving the plastic hinge away from the column face during an extreme event such as an earthquake, thus improving the ductility of the structure. Until now, there was very little known of their behaviour under fire conditions. Accordingly, the current paper provides a detailed description and analysis of the fire test on a RWS connection, during which the arrangement lasted for around 16 minutes of standard fire exposure. It also describes the development of a numerical model, which is validated against the test data. The purpose of the model is to enable a more thorough examination of the various parameters and variables that may exist in a real structure, subjected to a real fire.
Damage evaluation of steel frame subjected to impact load at midspan
Authors: Chen Ying , Chen Wensu , Hao Hong , Nie Zhenhua 
Published: September 2023

AbstractThe lower floors of the multi‐storey structure can be impacted by the debris from the upper floor caused by gas and bomb explosion, which may induce damage or failure of the impacted substructure and lead to progressive collapse of large‐scale structure. The behavior of the frame with a steel beam and two adjacent beam‐column joints was numerically analyzed when the beam was impacted at midspan by various combinations of impact mass and velocity. The failure mode of the joints, the impact load and midspan displacement were analyzed. It shows that the beam‐column joint fails prior to the beam under all impact loading scenarios. The residual bearing capacity of the frame was also studied by statically pushing‐down the substructure after impact loading. A damage index was proposed using the residual capacity of the frame after impact loading divided by the static capacity of the joint without impact loading, and four damage levels, i.e., the minor damage, medium damage, severe damage, and collapse, were defined by the damage index. The boundaries of different damage levels of the frame under various impact loads were fitted, and it can be used to evaluate the damage level of the frame subjected to possible impact loads.
Influence of loading frequency on ULCF life of structural steel under variable surface roughness
Authors: Saleem Aleena , Tamura Hiroshi , Katsuchi Hiroshi 
Published: September 2023

AbstractThis paper investigates the effects of a wide range of loading frequencies ranging from 0.005 to 5 Hz and blasting induced surface roughness ranging from 20 to 100 μm on the ultra‐low cycle fatigue (ULCF) life of structural steel. The combined effect of these parameters on ULCF life has not been investigated so far. To this aim, comprehensive ULCF tests were performed on steel specimens under a constant displacement‐controlled environment until the failure occurred. The experimental results manifest that the surface roughness and loading frequency are the governing parameters affecting the ULCF life. The test material exhibits cyclic softening behavior under all loading conditions. An increase in loading frequency from 0.005 to 5 Hz causes a significant increase of 33% and 27% in ULCF life for 20 and 100 μm rough specimens, respectively. However, the effect of frequency on ULCF life becomes less significant at higher values of surface roughness. Moreover, an increase in surface roughness from 20 to 100 μm causes a significant reduction of about 45% and 47% in ULCF life at the loading frequencies of 0.005 and 5Hz, respectively. Furthermore, a correlation between fatigue life and loading frequency as a function of surface roughness is derived by the power law relationship.
LOCALISED FIRE ASSESSMENT OF A STEEL STRUCTURAL SOLUTION IN A PILOT BUILDING
Authors: Gamba Antonio 
Published: September 2023

AbstractMany tragic fires in the past decades have highlighted the importance of fire safety engineering and its meaningful application in the engineering field. With a constant and significant growth of the research the classical approach based on prescriptive time‐temperature curve, where the gas temperature is assumed to be constant within the entire compartment and always increasing on time has been challenged by a performance‐based one. Performance‐based approach is aiming to represent the fire accounting for more physics than the prescriptive approach, considering ignition, fire growth burning and cooling phase. Nowadays practitioners facing the design stage of a project have to face the choice between designing with prescriptive or performance‐based approach. In this work a comparison between design using performance based and a prescriptive approach will be provided. In particular, the building is under development in the framework of a demonstration RFCS (Research Found for Coal and Steel) project called DREAMERS, founded by the European Commission. The chosen structure for this example is an 800 m2 steel building, which will be built in the Campus of the University of Salerno (Italy). The main peculiarity of the building is the implementation of all the most advanced technologies for the construction of a resilient structure in terms of seismic, robustness and fire safety. The building is designed in steel and steel composite solutions, following a holistic design approach and foreseeing a life time monitoring of its behavior. The flooring system is made of Asymmetric Floor Beams (AFB) and Cofradal® 260, whereas vertical elements are hot rolled HEB sections. The work here presented is showing some of the main challenges related to the fire design as well as application of next generation localised fire models.
ON THE RELIABILITY OF A NUMERICAL TRAVELLING FIRE MODEL
Authors: Gamba Antonio 
Published: September 2023

AbstractThe ongoing urbanization of our society is leading to the situation that many people live, work and gather in buildings of larger size. Open space office buildings are becoming more common, airport terminals are continuously increased in size and new larger railway stations are being built. When it comes to compartments with larger floor areas, the fire may be localized, which means that the fire does not extend on the whole floor. Yet, even when the fire load is distributed, such as in open space office buildings, the area where combustion is raging moves during the fire leading to so‐called “travelling fires”. The classical view of compartment fire with the strong assumption of uniform temperature in the compartment has been challenged, several travelling fire models have been proposed to address the phenomenon. Validation of these models is still scarce. This work is about the assessment of reliability and accuracy of a numerical travelling fire model implemented in a software called GoZone. The assessment is done mainly by comparison of relevant output in a fire compartment such as fire growth rate as well as by comparison of gas temperature, rate of heat released and resulting steel temperature. In the framework of this paper, only a part of the entire assessment focused on office building is presented.
Structural analysis of rack upright frames under a pure compression load by means of a nonlinear Generalized Beam Theory analysis
Authors: Bonada Jordi , Casafont Miquel , Bové Oriol , López Ignasi 
Published: September 2023

AbstractRack upright frames of conventional pallet racking systems are obtained by the assembly of uprights and braces or diagonals. Rack uprights are commonly mono‐symmetric open thin‐walled members with regular perforations along their length. These perforations are used to enable the connection with braces and beams by means of bolts or hooks. The structural behaviour of a rack upright frame under a pure compression load, in which the buckling phenomenon has a relevant influence, depends on several geometrical parameters, such as the column cross‐sectional dimensions, perforations characteristics, frame length, distance between braces, etc. Therefore, these particular issues should be considered to perform a proper structural analysis.In this paper, the structural behaviour of a pallet rack frame under a pure compression load is analysed by means of eigenbuckling and geometrically nonlinear Generalized Beam Theory (GBT) analyses. The influence of GBT deformation modes involved in the analysis is discussed. Moreover, different approaches to reproduce the connection between uprights and braces are presented and discussed. Finally, GBT results are compared with beam, shell finite element analysis and experimental values.
Seismic behaviour of dissipative beam‐to‐column steel and steel‐concrete composite joints
Authors: Skarmoutsos Georgios , Kuhlmann Ulrike 
Published: September 2023

AbstractThe present paper deals with the seismic behaviour of bolted steel and steel‐concrete composite partial‐strength beam‐to‐column joints with endplate connections. In a series of experiments in total 12 two‐sided internal joint specimens were tested, of which 3 were all‐steel and 9 steel‐concrete composite. For those, 5 parameters were varied, (i) thickness of endplate tep, (ii) vertical distance of T‐stub bolt rows e4, (iii) distance of first shear stud to face of the endplate l, (iv) reinforcement ratio of concrete slab ρ and (v) number of bolt rows. The design of the specimens was performed with the help of both the component model as given in EN 1993‐1‐8 and a FEM model. The chosen parameter values were optimised to provide, for given beam and column sections, an upper and lower limit regarding moment capacity and rotational stiffness, for sufficient energy dissipation and ductility. The experimental results show that the stiffness of the concrete slab leads to a significantly different response of composite compared to all‐steel joints, especially regarding rotational stiffness and capacity of the joint as well as flexural stiffness of the (composite) beams. The composite joints present an overall better seismic behaviour compared to all‐steel ones.
Preventing failure propagation in steel truss bridges
Authors: Sánchez‐Rodríguez Ana , López Santiago , Makoond Nirvan , Buitrago Manuel , Riveiro Belén , Adam José M. 
Published: September 2023

AbstractMetal and steel truss bridges are essential for transportation networks worldwide but are vulnerable to collapse due to deterioration and increasing traffic loads, particularly for ageing structures. Several bridge collapses, such as the Seongsu bridge (South Korea, 1994), I‐35 bridge (USA, 2007), and Chauras bridge (India, 2012), have highlighted the need to develop accurate robustness assessment strategies and efficient mitigation of collapse risks. This paper summarizes results of experimental and computational studies for a steel riveted bridge with a truss‐type structure. The experimental component presented involves unique tests to be performed on a 21 m full‐scale bridge span subjected to the failure of different elements under laboratory conditions. The paper then presents a first approach to explore different damage and failure scenarios for steel truss bridges, which will assist in defining data collection strategies for optimised monitoring and developing data analysis methods for real‐time diagnosis of ageing bridges. With this, the paper contributes to avoiding progressive collapses and presents a framework, developed as part of an ongoing project, to identify vulnerable zones for prioritising monitoring systems that anticipate failure propagation and prevent collapse. The framework is based on a systematic analysis of past bridge failures and simulations of carefully designed generic cases.
Study on Global Imperfection of Modular integrated Construction Structures for Second‐order Analysis
Authors: Ding Yue‐Yang , Liu Si‐Wei , Liu Yao‐Peng , Chen Wen‐Feng , Chan Siu‐Lai 
Published: September 2023

AbstractThe global imperfection significantly influences the stability design of the Modular integrated Construction (MiC) buildings. Currently, the initial global imperfection shapes recommended for MiC structures are formulated based on steel frames whose members are continuously connected. In practice, the columns and beams in MiC structures are composed of the members of adjacent module units, which are discontinuously connected through the special joints. Ignorance of such discontinuous features in MiC structures leads to an inappropriate estimation of the structural resistance. This paper introduces a new initial imperfection shape for MiC structures considering out‐of‐verticality of module columns and eccentricity between modules, capturing the discontinuous feature. Random initial imperfection shapes were generated using Monte‐Carlo simulation based on tolerances in regulations. The proposed imperfection shape is adopted in the analysis of a typical MiC structure and the result is compared with results from existing global imperfections in design codes. This research provides a practical global imperfection for the second‐order analysis and design of steel MiC structures. Recommendation for basic value of the proposed imperfection shape is also provided.
Dynamic Increase Factors for progressive collapse anaylsis of steel structures accounting for column buckling
Authors: Possidente Luca , Freddi Fabio , Tondini Nicola 
Published: September 2023

AbstractMan‐made hazards, such as fire, explosions, or impacts, may induce the progressive collapse of structures, in which the localised failure spreads from the single affected structural component to other parts of the structure. A typical approach to model progressive collapse consists in performing static column removal analyses considering a Dynamic Increase Factor (DIF), whose determination becomes paramount to account for the dynamic effects related to a sudden column loss scenario. Current recommendations on the definition of such factor mainly consider a beam‐type collapse in non‐linear analyses, though different mechanisms, e.g., column buckling, may govern progressive collapse events. This paper presents the determination of the DIFs through a numerical procedure for five steel structures with an increasing number of storeys. Both global and local imperfections are modeled to account for the geometric non‐linearities of the structure and column buckling. DIF values are obtained considering two different Engineering Demand Parameters (EDPs), suited for describing beam‐type and column‐type mechanisms respectively. The evaluated DIFs are compared with the values recommended in the current UFC design prescriptions for progressive collapse, and considerations on the choice of the appropriate DIF values are provided.
Seismic Performance of Multistory Chevron‐braced Steel Structures with Yielding Beams
Authors: Orgev Ahmet Alperen , Selamet Serdar , Vatansever Cuneyt 
Published: September 2023

AbstractLateral loads are resisted by braces in concentrically braced frames. Therefore, braces meet the demand for the load combination based on the seismic provisions. The rest of the system including the connections are determined according to the capacity‐based design, where the brace members yield under tension and buckle under compression. Chevron or inverted V‐braced frames are generally preferred because they allow large openings for doors and windows. However, the seismic‐design requirements in current building codes lead to deep, heavy chevron beams to resist the unbalanced load at beam members due to pre‐ and post‐buckling compressive strength deterioration and full tensile yielding of the braces. This results in uneconomical design. Recent large‐scale experiments of chevron‐braced frames have demonstrated that limited beam yielding is not detrimental to chevron‐braced frame behavior and on the contrary, it utilizes a second yielding mechanism and thereby increases the story drift capacity at which the braces fracture. Also, they propose a new design method for chevron braced frame with yielded beam. This paper expands the previous findings by investigating the seismic performance of 9‐story structures which are designed according to provisions and proposed method. Structural analysis program SAP2000 is utilized for linear design by modelling the full‐scale 9‐story building. Nonlinear finite element analysis software Perform 3D is utilized for the nonlinear time history analysis in which only a single chevron braced frame is modelled. Results show that the proposed building design has larger interstory drift ratios. However, the adjusted collapse margin ratio and the collapse probability for maximum considered earthquake satisfy the required limitations. In other words, the proposed chevron frame design offers a more economical alternative with no significant tradeoff in seismic performance.
Experimental characterisation of connection behaviour for cold‐formed steel panels sheathed with calcium silicate boards
Authors: Ringas Nikolas , Huang Yuner 
Published: September 2023

AbstractConstruction trends aim towards the use of modular cold‐formed steel (CFS) wall panels, comprising of CFS studs and sheathing. Their capacity is influenced by different components employed, with the fastener connection between the sheathing board and the frame being the most critical. Furthermore, as repeated loading scenarios are expected to occur within the life cycle of a structure, it is important to address the uncertainty surrounding the connection behaviour under cyclic loading. A series of push‐out tests were carried out for cold‐formed steel sections sheathed with Calcium Silicate Board, using monotonic and cyclic loading protocols. The cyclic protocol employed focuses on the serviceability limit state with a repeated load‐unload step applied for 10 cycles. Two assembly arrangements, namely back‐to‐back and single stud arrangements were employed. Push‐out test results are presented and discussed herein. Recommendations for the test procedure and design of connection in sheathed cold‐formed steel shear walls are proposed.
Experimental Testing of Post‐installed Anchors for Use in Retrofitting of RC Frame with Steel Braces
Authors: Tewatia Devyani , Kumar P. C. Ashwin 
Published: September 2023

AbstractThe retrofitting of deficient Reinforced Concrete (RC) frames, particularly those with strength and stiffness irregularities such as Open Ground Story, has been widely researched. Steel braces are a great option for retrofitting these buildings, but the narrow section sizes of existing beams and columns pose a challenge. However, post‐installed chemical anchors can provide an efficient, cost‐effective solution for connecting such structures with steel braces, provided that they are designed properly to account for all possible failure modes. This study investigates the use of post‐installed chemical anchors to connect steel braces with narrow‐beam column subassemblies in existing low‐ to mid‐rise Open Ground Story buildings. The three experiment are considered to test the bracing conditions with elastic and yielding brace. The gusset plate is designed as per Balanced Design Procedure to obtain an economical section with controlled yielding and failure sequence. The forces on gusset plate are computed using the Uniform Force Method, which helps in designing the post‐installed anchor dimension and spacing. A comparison is drawn between the three test from which it is seen that the chemical anchors perform well in all cases and conventional brace shows expected performance.
The plastic deformation capacity of the structural system for thin‐web steel beam reinforced with stiffener plates
Authors: Nitawaki Masashi , Ishii Daigo 
Published: September 2023

AbstractJapanese buildings are generally designed as moment‐resistant frames, and beam ends are required to have high bending strength and high plastic deformation capacity. With H‐shaped beams, the contribution of the web to the bending strength is small, so H‐shaped beams with thick flanges and thin webs are used to reduce the amount of steel required for construction. However, H‐shaped beams with thin webs are prone to local buckling at the ends of the beam, resulting in poor plastic deformation performance. The authors have developed a structural system of steel structures in which the ends of beams are reinforced by stiffener plates with the aim of improving the plastic deformation capacity. Especially when these structural systems are applied to a high‐rise building with large‐sized beams, the effect of reducing the amount of steel is high by reducing the thickness of the web. Reducing the amount of steel can be expected to reduce the loads on the environment and the construction cost. In this paper, the simple stiffening method is proposed with stiffeners that can improve factory manufacturability. Secondly, to confirm the plastic deformation capacity of a stiffened steel beam, a series of cyclic loading tests is carried out using 1/2 scale specimens.
Strengthening of axially compressed bars in lattice towers under load – experimental investigations
Authors: Jastrzębski Kamil , Ślęczka Lucjan 
Published: September 2023

AbstractThis paper presents the results of experimental research, in which hot‐rolled single steel angle members L65×65×7 were strengthened under axial compression. Strengthening was carried out by attaching an additional angle (L65×65×7 or L50×50×5) by a clamp system. The reinforced angle, the reinforcing element and the clamps were hot‐dip galvanized. The paper compares the difference between buckling behaviour and the ultimate load capacity elements strengthened under no load with the elements having the same geometry, in which the strengthening was carried out under the load. The level of force transmission from the reinforced to the reinforcing member is also recognized. The results show the influence of the size of the reinforcement element, the slenderness of the reinforced member, and the spacing of the clamps on the effectiveness of reinforcement. The effect of preload on the ultimate load capacity of the axially loaded element was found to be insignificant in the study conducted (no more than ±4.2%).