bluuebunny/crossref_metadata_2025_split huggingface dataset:
10.12: Numerical modelling of steel sheathed LSF walls under fire conditions
Authors: Dias Yomal , Keerthan Poologanathan , Mahendran Mahen 
Published: September 2017

ABSTRACTFire performance of light gauge steel framed (LSF) walls sheathed with gypsum plasterboards has been investigated using experimental and numerical studies by many researchers in the past. Provision of cavity or external insulation, improving the thermal‐mechanical properties of plasterboard, and changing the stud geometry are several options previously employed to enhance the Fire Resistance Level (FRL) of such wall systems. Past studies of steel sheathed cold‐formed steel (CFS) framed walls have shown that the use of steel sheathing improves the shear strength of LSF walls. However, such studies have not investigated the possible improvements to the fire performance of LSF walls due to the use of steel sheathing in addition to plasterboards. This numerical study investigates the thermal performance of three common LSF wall configurations sheathed with steel sheets on both sides under fire conditions. Three steel sheathing configurations (internal and/or external sheathing) were considered for each LSF wall. Thermal Finite Element (FE) models were developed and used to simulate the heat progression across the walls, following validation using previous experimental studies. The walls were exposed to ISO 834‐1 standard fire curve on one side. Results were then compared with those from LSF walls sheathed only with plasterboards. Internal steel sheathing was found to be capable of reducing the ambient side temperatures compared to plasterboard only walls due to the lower emissivity of steel, whereas external steel sheathing increased them further. Although the stud hot flange (HF) temperatures are generally increased with the addition of steel sheets, provision of back‐blocking was able to eliminate this deficiency. A novel arrangement is proposed for back‐blocking which is found to significantly delay the stud temperature rise and improve the FRL. The use of corrugated steel sheet profiles is found to reduce both the stud and ambient side plasterboard temperatures. The results from this study give useful information to develop load bearing and non‐load bearing LSF walls with superior fire performance. This paper presents the details of this numerical study and the results.
10.15: Thermal modelling of LSF floor systems made of lipped channel and hollow flange channel section joists
Authors: Steau Edward , Keerthan Poologanathan , Mahendran Mahen 
Published: September 2017

ABSTRACTBuildings that are not designed to have fire safety measures are not able to endure the extreme conditions in a fire event. Hence considerably more attention is being placed on the fire safety of buildings in recent times. Light gauge steel framed (LSF) floor systems are commonly used in buildings as they provide significant benefit by reducing weight and cost while increasing construction efficiencies. To obtain a satisfactory fire resistance level, floor systems must comply with a number of requirements specified in codes relating to fire resistance level. However, to understand the heat transfer process within LSF floor systems usually requires numerous complex fire tests. These tests are extremely expensive and time consuming. Therefore three‐dimensional finite element models were developed and used in this study to investigate the heat transfer in LSF floor systems made of different joist sections such as Lipped Channel and Hollow Flange Channel beam sections. Standard fire curve was defined as an amplitude curve following a time‐temperature profile based on ISO 834 standard fire curve. The time‐temperature curves obtained from the finite element analyses were compared with available experimental results to determine their accuracy in predicting the heat transfer in LSF floor systems made of the two chosen joist sections. Results showed that the proposed three‐dimensional finite element models can accurately predict the heat transfer of LSF floor systems made with lipped channel and hollow flange channel section joists. They also highlighted the differences in the thermal performance when different joist types are used. This paper presents the details of a three‐dimensional thermal modelling study of LSF floor systems made of lipped Channel and hollow flange channel section joists and the results. Innovative LSF floor systems were also proposed using the validated thermal models to enhance the fire resistant rating.
10.21: Post‐fire response of slender concrete‐filled steel tubular columns
Authors: Ibañez Carmen , Albero Vicente , Espinos Ana , Romero Manuel L. , Hospitaler Antonio 
Published: September 2017

ABSTRACTIn this paper, a fiber beam model for the simulation of the post‐fire response of slender concrete‐filled steel tubular (CFST) columns is presented. First, the model is validated against experimental results and subsequently it is employed to analyse the post‐fire response of circular CFST columns. Actually, when a fire takes place in a building, the columns are supporting load even while the fire is being extinguished. For that reason, it is important to take into account this loading condition when trying to predict their post‐fire behaviour. Therefore, in this research, the analysis is initiated when a constant load is applied to the column and, simultaneously, the specimen starts to be heated following an established heating regime (ISO 834). Maintaining the applied load constant, the cooling stage prolongs until the column reaches the room temperature. The post‐fire response of the CFST columns is studied by means of a mechanical analysis where the applied load increases progressively up to the column failure. The model considers realistic features typical from the fire response of CFST columns, such as the existence of a gap conductance at the steel‐concrete interface or the sliding and separation between the steel tube and the concrete. Finally, the post‐fire response of CFST columns is studied in depth taking as reference experimental results used in validation. The variation of the residual strength with load level for realistic fire resistance times is calculated and analysed.
10.32: Experimental study on high temperature elastic modulus of China made high strength structural steel
Authors: Li Guo‐Qiang , Huang Lei , Zhang Chao 
Published: September 2017

ABSTRACTHigh strength structural steel (HSSS) has better economic and environmental benefits than mild structural steel, and becomes more popular in the building construction projects. The current codes for fire safety design of steel structures is mainly developed based on the test data from mild structural steel and might be not applicable to the high strength structural steel. This paper reports an experimental study on the high temperature elastic modulus of China made high strength structural steel. Both static and dynamic test methods were used to determine the elastic modulus of Q550, Q690 and Q890 China grade steel at temperatures ranging from 20 °C to 800 °C. Suspended coupling bending resonance method was used to measure the dynamic elastic modulus. The reduction factors of elastic modulus from test data were compared with the reduction factors determined by current codes, including the Chinese code CECS200, the Eurocode 3, the American code AISC and the Austrian code AS4100, and by other researchers. The study found that unlike the static reduction factors (reduction factors determined by the static method) the dynamic reduction factors are not sensitive to the steel grade. The static elastic modulus is greater than the dynamic elastic modulus at low temperatures and is less than the dynamic modulus at high temperatures. Both the static and dynamic reduction factors of HSSS are greater than the elastic modulus reduction factors employed by the current codes. Design equation for dynamic elastic modulus of HSSS was derived from curve‐fitting of the test data.
10.36: Advanced numerical analysis of steel, concrete and composite structures under fire conditions
Authors: Pires Dalilah , Barros Rafael Cesário , Lemes Ígor José Mendes , Rocha Paulo Anderson Santana , da Mota Silveira Ricardo Azoubel 
Published: September 2017

ABSTRACTHigh temperature in common fire causes changes in physical characteristics and mechanical strength of the materials used in the structures. In both steel and concrete, such characteristics deteriorate during the exposure to fire, and the structure load capacity and stiffness are reduced significantly with the increasing temperature. This work is on advanced analysis context of structures under fire, and it aims to develop a computational system for analysis of steel, concrete and composite structures in fire situation, based on the finite element method. The use of advanced analysis as a methodology of analysis/design of structures has various advantages. Among these advantages, there is the capture of strength limit and stability of a structural system and its members directly, without the need for separate verification of each member capacity. This provides a more realistic analysis and determine adequately the performance of a structure in a real fire. To achieve the objective, the CS‐ASA (Computational System for Advanced Structural Analysis) is used and expanded to advanced analysis of structures in fire situation, taking advantage of existing features and adding new ones. Two new modules were created: CS‐ASA/FA (Fire Analysis) and CS‐ASA/FSA (Fire Structural Analysis). The first aims to determine the temperature field in the cross section of the structural elements by FE thermal analysis in permanent and transient regimes. The second was created to perform the inelastic second‐order analysis of structures under fire considering the refined plastic hinge method coupled to strain compatibility method. The adopted numerical methodology is described and, for a more comprehensive validation of the implemented modules, various structural systems under fire are analyzed.
11.01: Shaking table tests on cold‐formed steel building sheathed with gypsum panels
Authors: Macillo Vincenzo , Bucciero Bianca , Terracciano Maria Teresa , Pali Tatiana , Fiorino Luigi , Landolfo Raffaele 
Published: September 2017

ABSTRACTShake table tests are particularly indicative to assess dynamic properties and seismic response under earthquakes in the case of a new building structure. In last years the University of Naples was involved in the research project named “Energy Efficient LIghtweight‐Sustainable‐SAfe‐Steel Construction” (Project acronym: ELISSA), which was devoted to the development and demonstration of enhanced prefabricated lightweight CFS skeleton/dry wall constructions with improved antiseismic properties. Within the ELISSA project, in order to evaluate the global building seismic response, shake table tests on a full‐scale two‐storey building, named “ELISSA mockup”, were carried out. The mockup was tested in two different conditions. In the first condition the mockup included mainly structural components of walls, floors and roof, whereas in the second condition it was completed with all nonstructural components. This paper presents the testing program and the obtained results in terms of dynamic identification (fundamental period and damping ratio) and earthquake performance (global lateral response, building drift, acceleration amplification, diaphragm response, and observed damage).
11.04: Examination of the Canadian provisions for the seismic stability of steel structures
Authors: Breton Nicolas , Tremblay Robert 
Published: September 2017

ABSTRACTThis article presents the seismic stability provisions of the CSA S16 design standard for steel structures in Canada. These provisions include notional lateral loads as well as lateral load amplification for P‐delta effects evaluated at maximum lateral displacements including inelastic response. The impact of these provisions is examined through nonlinear response history analyses performed on single‐degree‐of‐freedom models representing steel braced frames for buildings varying from 1 to 15 storeys in height. Buckling restrained braced frames and concentrically braced frames are investigated. The structures are located in eastern and western seismic regions of Canada to account for the difference in anticipated ground motion signature. For each location, firm ground and soft soil conditions are considered. The results show that current code provisions for seismic are sufficient to ensure stable seismic response of structures located in eastern Canada where ground motions are richer in high frequencies. Structural collapse was observed for one third of the structures located in western Canada. Most failures occurred for taller buckling restrained braced frames subjected to long duration subduction interface earthquakes. Collapse also took place for low‐rise concentrically braced frames.
11.06: Application of hybrid simulation for the evaluation of the buckling response of steel braced frame columns
Authors: Imanpour Ali , Leclerc Martin , Siguier Romain , Tremblay Robert 
Published: September 2017

ABSTRACTHybrid simulation is an economical structural testing technique in which the critical part of the structure expected to respond in the inelastic range is tested physically whereas the rest of the structure is modelled numerically using a finite element analysis program. This paper describes the application of hybrid simulation for steel I‐shaped columns in Multi‐Tiered Braced Frame (MT‐BFs) structures. A full‐scale W250×101 column part of a two‐tiered concentrically braced frame was physically tested while the rest of the frame was numerically analysed using the OpenSees finite element program. The development and main challenges of the hybrid simulation are first described and the main findings of the hybrid simulation are then presented. The test results show that the testing technique is an effective experimental tool to generate reliable data on column stability limit states. Furthermore, the results from the hybrid simulation confirmed the findings of previous numerical simulations to assess the seismic response of columns in steel braced frames.
11.10: Probabilistic theory of plastic mechanism control
Authors: Castaldo Paolo , Nastri Elide , Piluso Vincenzo , Pisapia Alessandro 
Published: September 2017

ABSTRACTThis work aims at the development of an advanced method for the seismic design of Moment Resisting Frames (MRFs) based on the evaluation of the probability of failure in the attainment of a collapse mechanism of global type in case of stochastic frames. Therefore, the method presented constitutes the probabilistic version of the Theory of Plastic Mechanism Control (TPMC) already successfully developed for frames with deterministic material properties. With reference to MRFs whose members have random values of the yield strength, the failure domain derives from all the possible collapse mechanisms. Under the point of view of structural reliability analysis, the term “failure” means the attainment of a collapse mechanism different from the global one. The design requirements normally needed to prevent undesired collapse mechanisms are probabilistic events within the framework of the kinematic theorem of plastic collapse. At each event corresponds a limit state function representing a hyperplane in the space of the random variables, so that the failure domain is a manifold surface resulting from the intersection of the hyperplanes corresponding to the limit states of the single events. Because of plastic hinges in frame's members are common to many different mechanisms, the single limit state events are correlated. Therefore, by applying the theory of binary systems and taking into account that, from the structural reliability point of view, the limit states are events located in series, the probability of failure is computed by means of Ditlevsen bounds.
11.11: Rocking damage‐free steel column base with friction devices: Development of advanced 3D finite element models in Abaqus
Authors: Dimopoulos Christoforos A. , Freddi Fabio , Karavasilis Theodore 
Published: September 2017

ABSTRACTColumn bases are critical components of a seismic‐resistant steel building as they transfer gravity and lateral forces to the foundations. This paper focuses on the finite element (FE) modelling of a rocking damage‐free steel column base, which uses post‐tensioned high strength steel bars to achieve self‐centering behavior and friction devices to provide energy dissipation capacity. Contrary to conventional steel column bases, the monotonic and cyclic moment‐rotation behavior of the column base can be easily described using simple analytical equations. An advanced three‐dimensional FE model for the column base is developed in ABAQUS. The techniques used to overcome convergence issues in numerical simulations as well as the constitutive laws for the nonlinear behavior of materials and friction interfaces are described in detail. The FE model provides results that are in very good agreement with the results from the analytical moment‐rotation equations. The FE model results are also used to validate a simplified numerical model in OpenSees. Moreover, the FE model provides results that help to assess the level of stress concentration in critical areas of the column base and to evaluate a step‐by‐step design procedure that ensures damage‐free behavior, self‐centering capability, and adequate energy dissipation capacity.
11.12: Derivation of the cyclic behaviour of components in bolted end‐plate beam‐to‐column joints using FEM
Authors: Augusto Hugo , Castro José Miguel , Rebelo Carlos , Simões da Silva Luís 
Published: September 2017

ABSTRACTIn this paper a detailed procedure to isolate the main dissipative components of bolted end‐plate beam‐to‐column steel joints under cyclic loading, and to identify their force‐displacement relationships by analysing the stress and deformation fields in the FE models is proposed. The objective is generalise the component method prescribed in EC3‐1‐8 [1] extending it to reversal loading. It is worth noting that the proposed procedure is quite flexible, and that the assessment of the forces will depend on the idealized mechanical model, although the procedure can be easily adapted to any compatible mechanical model. A detailed numerical model of end‐plate bolted joints is developed using the ABAQUS FE package, capable of representing the various joints components and the several sources of nonlinearity associated to them. The numerical models were previously validated against monotonic and cyclic experimental test data obtained by the research team and with data available in the literature. The proposed procedure is then applied to the developed numerical models, of representative double‐extended end‐plate joints, the force‐displacement relationships are extracted and compared with those obtained from EC3–1–8.
11.13: Hybrid seismic protection system: Buckling restrained brace of nano‐micro composite magneto rheological damper
Authors: Vulcu Cristian , Dubină Dan , Popa Nicolae , Vekas Ladislau , Ghiţă Gheorghe , Sireteanu Tudor , Borbath Istvan , Oprescu Radu 
Published: September 2017

ABSTRACTThe ongoing research project SEMNAL‐MRD (Seismic Protection of Engineering Structures through Dissipative Braces of Nano‐Micro Magneto‐Rheological Fluid Dampers), aims to develop a seismic protection system employing a semi‐active structural control system. The most promising devices appear to be magneto‐rheological (MR) dampers. The current paper presents a case study related to the seismic response of multi‐storey frames equipped with dampers. The paper also describes the typology and working principle of MR dampers. Furthermore, the innovative solution for the current MR damper of composite nano‐micro MR fluid of passive/semi‐active control is presented in terms of technical solution and principle scheme. The experimental and numerical investigation program, developed for the characterization of the MR damper prototype of 10tf capacity, is described. The experimental investigations are to be performed on the MR damper, and respectively on the brace‐damper assembly, for which conventional as well as buckling restrained braces will be considered. Current outcomes of the ongoing experimental and numerical investigations, and the main conclusions are finally presented.
11.14: Seismic performance of high‐strength‐steel frame with buckling hinge beams in energy dissipation bays
Authors: Ke Ke , Chen Yiyi , Yam Michael C.H. 
Published: September 2017

ABSTRACTAlthough steel moment resisting frame (MRF) systems had long been recognized as effective seismic resistant structures, recent earthquake events and seismic loss estimations indicated that uniform damages of structural members and significant residual deformations would be expected after even a moderate earthquake event for steel MRF systems designed following the conventional ductility‐based design philosophy, and this incompleteness produced the impetus for overhaul of design methodologies and developing innovative systems. With the goal of enhancing the seismic performance of steel MRF structures in low‐to‐moderate seismic regions, this research explored the seismic behavior of high‐strength‐steel (HSS) frame with energy dissipation bays (EDBs) equipped with buckling hinge beams, denoted as the HSSF‐BHEDB system. In particular, the HSS frame is composed of steel with the nominal yield strength higher than 460 MPa, and the buckling hinge beams in the EDBs are constructed with cross‐sections classified as Class 3 or Class 4 by Eurocode 3. The motive of the novel design concept was to improve the structural nonlinearity of steel MRF systems with encouraging damage evolution mode and controllable residual deformations under earthquakes, and the limited energy dissipation of both the buckling hinge beams composed of slender cross‐sections and HSS members can provide a solution for structures in low‐to‐moderate seismic regions. In this work, the design concept and the rationale of the HSSF‐BHEDB were explored in detail. Then, a large‐scale quasi‐static test of a structure was conducted to provide experimental evidence and assess the feasibility of the design concept, and the behavior of the specimen from inception of yielding to failure was completely investigated. The test results showed that the system was characterized by the damage‐control behavior that diverted inelastic damages in the buckling hinge beams of the energy dissipation bay (EDB) in a wide deformation range. In the stage where the HSS frame initiated inelasticity and the energy dissipation of buckling hinge beams deteriorated, a ductile manner was still achieved. In addition, the controllable residual deformations of the specimen highlighted the satisfactory recentering behavior of the HSSF‐BHEDB structure. Lastly, the applicability of the bilinear hysteretic model of significant post‐yielding stiffness ratio and trilinear hysteretic model for featuring the hysteretic behavior of the HSSF‐BHEDB system in different yielding stages were validated by the test results.