12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018

URI permanente para esta colección

https://riunet7pro.upv.es/handle/10251/107280

After the success of ASCCS conference series: Harbin (1985,1988,2006), Fukuoka (1991), Kosice (1994), Innsbruck (1997), Los Angeles (2000), Sydney (2003), Leeds (2009), Singapore (2012), Beijing (2015) the upcoming 12th international conference on ‘Advances in Steel-Concrete Composite Structures’ (ASCCS 2018) will be held by Universitat Politècnica de València, Spain on June 27-29, 2018.

The conference is intended to provide a forum to discuss the recent progress and advances in the research, design and practice of steel-concrete composite as well as hybrid structures.

Futher information in: http://asccs2018.webs.upv.es/

Examinar

Mostrando 1 - 20 de 117

Steel Concrete Composite Systems for Modular Construction of High-rise Buildings
(Editorial Universitat Politècnica de València, 2018-06-05) Liew, Richard; Dai, Z.; Chau, Yie Sue; National Research Foundation, Singapur
[EN] Modular construction has gained popularity and attention particularly in low-rise building lately due to its numerous advantages: faster construction speed, better quality control, reduction in work force and construction waste, etc. This innovative technology promotes off-site manufacturing of modular units and on-site assembly, improving the construction efficiency and productivity. However, modular construction is not commonly used in high-rise buildings because of the joints’ flexibility as well as manufacturing and construction tolerance, which have significant impact on the overall stability of the building. This paper highlights the existing challenges of modular construction of high-rise buildings and provide several options to address these challenges. Firstly, the weight of a module is constrained by the transportation and lifting crane capacities. For this reason, lightweight concrete is introduced together with structural steel section to form lightweight steel-concrete composite system to reduce the weight of the module without compromising the strength and stiffness. Secondly, to speed up the site assembly of modular units, special joints are developed to resist the forces due to gravity and horizontal loads. Fast and easy joining techniques with acceptable tolerance control are essential to ensure the structural integrity and stability of the building. Finally, the innovation for productivity can be maximized by implementing automation technologies in the manufacturing and construction of the modular units.
Fatigue and crack propagation investigations on composite dowels using an inclined single push-out test
(Editorial Universitat Politècnica de València, 2018-06-05) Wolters, Kevin; Feldmann, Markus
[EN] The current fatigue design of composite dowels is based on the structure stress concept for the steel part and upper load limitations to avoid concrete fatigue and a degradation of the composite joint. Therefore the aim of the existing concept is to avoid any fatigue of the composite structure. A fatigue concept considering residual load bearing capacity of torn steel connectors and the transfer of forces to less stressed composite dowels in the beam has great economic potential and leads to a better safety assessment. Therefore, further investigations of fatigue behaviour and crack propagation of composite dowels are necessary. In a first step a single composite dowel is investigated in small-part tests. By the use of finite element models a new inclined single push-out test stand has been developed in order to reproduce the force and stress distributions within a composite beam as precisely as possible with the small-part tests. This ensures the comparability of the crack initiation location and crack propagation. In the test series the influences of different stress ranges and cycle numbers on crack propagation of the steel dowel are investigated. Furthermore the residual load-bearing capacity is determined and compared to static load-bearing behaviour of uncracked steel parts of composite dowels. This paper concentrates on the numerical evaluation of crack propagation and residual capacity.
Seismic performance assessment of conventional steel and steel-concrete composite moment frames using CFST columns
(Editorial Universitat Politècnica de València, 2018-06-05) Silva, Antonio; Jiang, Yadong; Macedo, Luis; Castro, Jose Miguel; Monteiro, Ricardo
[EN] The research reported in this paper focuses on the assessment of the seismic performance of conventional steel moment-resisting frames (MRFs) and steel-concrete composite moment-resisting frames employing circular Concrete-Filled Steel Tube (CFST) columns. Two comparable archetypes (i.e. one steel MRF, with steel columns and steel beams; and one composite MRF, with circular CFST columns and steel beams) are designed, and used as the basis for comparison between the seismic performance associated with each typology. Both structures are designed against earthquake loads following the recommendations of Eurocode 8. The comparison of the obtained design solutions allows concluding that the amount of steel associated with the main structural members is higher for the steel-only archetype, even though the composite MRF has the higher level of lateral stiffness. This aspect is particularly relevant when one considers that a minimum level of lateral stiffness (associated with the P-Δ inter-storey drift sensitivity coefficient, θ), is imposed by the European code, which may ultimately govern the design process. The two case-studies are then numerically modelled in OpenSees, and their seismic performance is assessed through fragility assessment for a number of relevant limit states, and, finally, earthquake-induced loss estimation. In general, the results obtained clearly indicate that the composite MRF with circular CFST columns exhibits better seismic performance than the equivalent steel-only archetype. This is noticeably shown in the comparison of the fragility curves associated with the collapse limit state, which tend to show substantially higher probabilities of exceedance, at similar levels of 1st-mode spectral acceleration, for the steel-only case. Furthermore, seismic losses at several seismic intensity levels of interest tend to be higher for the steel MRF.
Semi-continous beam-to-column joints for slim-floor systems in seismic zones
(Editorial Universitat Politècnica de València, 2018-06-05) Vulcu, Cristian; Don, Rafaela; Ciutina, Adrian
[EN] The slim-floor building system is attractive to constructors and architects due to the integration of steel beam in the overall height of the floor, which leads to additional floor-to-floor space, used mostly in acquiring additional storeys. The concrete slab offers natural fire protection for steel beams, while the use of novel corrugated steel sheeting reduces the concrete volume, and replaces the secondary beams (for usual spans of steel structures). Currently the slim-floor solutions are applied in non-seismic regions, and there are few studies that consider continuous or semi-continuous fixing of slim-floor beams. The present study was performed with the aim to develop reliable end-plate bolted connections for slim-floor beams, capable of being applicable to buildings located in areas with seismic hazard. It is based on numerical finite element analysis, developed in two stages. In a first stage, a finite element numerical model was calibrated based on a four point bending test of a slim-floor beam. Further, a case study was analysed for the investigation of beam-to-column joints with moment resisting connections between slim-floor beams and columns. The response was investigated considering both sagging and hogging bending moment. The results are analysed in terms of moment-rotation curve characteristics and failure mechanism.
Numerical Behaviour of Composite K-Joints Subjected to Combined Loading and Corrosive Environment
(Editorial Universitat Politècnica de València, 2018-06-05) Saleh, Shameer; Hou, Chao; Han, Lin-Hai; Hua, You-Xing
[EN] Concrete filled steel tubular (CFST) truss structures have been adopted in various infrastructures worldwide for past several decades. Application of CFST truss is more prevalent especially in areas where harsh marine condition with chloride corrosion limits the design life of structures. Design of joints is one of the most complicated issues in CFST truss structures; and it becomes more critical when corrosion causes section loss in the outer steel tube. Improved designs in terms of economy and durability need to be suggested based on rational research on composite K-joints in corrosive environment, whilst such research is very limited up until now. This paper thus attempts to study the behaviour of circular concrete filled steel tubular (CFST) K-joints under combined effect of long-term loading and corrosion. A finite element analysis (FEA) model is presented and verified against existing test results. The model is then utilized to perform mechanism analysis of CFST K-joints under varying loading and corrosion situations. Failure modes, detailed propagation of yield and stress distribution between the core concrete in chord and the tubular steel is investigated, based on which a favourable mode of failure is suggested in terms of maximum joint capacity. Finally, a full range analysis of the load-deformation characteristics is carried out for various corrosion situations, with the corresponding joint strength as well as ductility predicted.
Experimental Study on Behavior of Shear Connectors Embedded in Steel-Reinforced Concrete Joints
(Editorial Universitat Politècnica de València, 2018-06-05) Nakamori, Riko; Kageyama, Yuki; Baba, Nozomu
[EN] This paper presents an experimental study on the behavior of shear connectors embedded in steel-reinforced concrete joints. In steel-reinforced concrete joints, the shear connectors are commonly used to transfer longitudinal shear forces across the steel-concrete interface. Further, in Japan, some studies in recently have also been undertaken to apply perfobond rib shear connector (PBL), which is a type of shear connectors developed in civil engineering, to the steel-reinforced concrete joints in building structures. To clarify the influence of the arrangement methods of headed studs and PBLs to reinforced concrete member on the joints, T-shaped subassembrages were tested under the monotonic tensil loading.This experiment is constituted of the following; Exp. I: Bond strength across the steel-concrete interface. Exp. II: Arrangement methods of these shear connectors to reinforced concrete member. The following can be drawn from the test results 1) The experimental values of the average maximum and residual bond strength are 0.230-0.280 and 0.15-0.18 N/mm2, respectively. 2) When the distance of between the upper surface of the reinforced concrete member from the first layer for headed studs are small, the failure mode of the specimens is similar to a concrete-cone type failure. 3) In case that the total number of headed studs or the hole provided to PBL is the same, the maximum load of the specimen with the parallel arrangement is larger than that of when shear connecters are vertically arranged. 4) The shear strength of headed studs in the joints embedded the steel member in the reinforced concrete member is estimated by superposing the average residual bond strength across the steel-concrete interface.
Experimental study on the thermal behaviour of fire exposed slim-floor beams
(Editorial Universitat Politècnica de València, 2018-06-05) Albero, Vicente; Espinós, Ana; Serra, Enrique; Romero García, Manuel Luis; Hospitaler, Antonio; Departamento de Mecánica de los Medios Continuos y Teoría de Estructuras; Escuela Técnica Superior de Ingeniería Industrial; Instituto Universitario de Investigación de Ciencia y Tecnología del Hormigón
[EN] Steel-concrete composite beams embedded in floors (slim-floors) offer various advantages such as the floor thickness reduction or the ease of installation of under-floor technical equipment. However, this typology presents important differences in terms of thermal behaviour, as compared to other composite beams, when exposed to elevated temperatures. These differences are due to their special configuration, being totally contained within the concrete floor depth. Moreover, the current European fire design code for composite steel-concrete structures (EN 1994-1-2) does not provide any simplified thermal model to evaluate the temperature evolution of each slim-floor part during a fire. Additionally, only a few experimental studies can be found which may help understand the thermal behaviour of these composite beams. This paper presents an experimental investigation on the thermal behaviour of slim-floor beams. Electrical radiative panels were used in the test setup to produce the thermal heating. The thermal gap between the lower flange of the steel profile and the bottom steel plate was studied, being found to be one of the most influential elements over the cross-section temperature gradient. The experimental campaign was developed by varying the cross-section configuration in order to evaluate the influence of this parameter over the slim-floor thermal behavior. Finally, the experiments carried out were used to develop and calibrate a finite element thermal model which may help in further research on the thermal behaviour of slim-floor composite beams.
The SMARTCOCO design guide for hybrid concrete-steel structures
(Editorial Universitat Politècnica de València, 2018-06-05) Somja, Hugues; Hjiaj, Mohammed; Nguyen, Quang Huy; Plumier, André; Degee, Hervé; European Commission
[EN] Standard buildings in steel and in reinforced concrete are constructed by two different industrial sectors with little interaction. Even steel-concrete composite buildings remain designed as steel structures, with a limited benefit of the presence of concrete slabs. For some years however, a more integrated design between both materials is used, merely in high rise and heavy loaded structures. This new trend is not supported by actual standards that give little guidance for the specific arrangements that come from this new practice. The RFCS SMARTCOCO research project is intended to fill these gaps in knowledge and provide design guidance for some composite elements covered neither by Eurocode 2 nor by Eurocode 4 : composite columns or walls reinforced by several fully encased steel sections, reinforced concrete columns reinforced by one steel section over the height of one storey and concrete flat slabs or beams connected to columns or walls by means of steel shear keys. Gaps in knowledge are mostly related to force transmission between concrete and embedded steel profiles. A generic design approach has been developed and then used to design test specimens. The results have been used to calibrate the design proposals. The output is a design guide which complements Eurocode 2 and 4.
Numerical investigation on slender concrete-filled steel tubular columns subjected to biaxial bending
(Editorial Universitat Politècnica de València, 2018-06-05) Espinós, Ana; Albero, Vicente; Romero, Manuel; Mund, Maximilian; Kleiboemer, Inka; Meyer, Patrick; Schaumann, Peter; Generalitat Valenciana
[EN] The behaviour of concrete-filled steel tubular columns under axial compression or combined compression and uniaxial bending has been deeply investigated in past years by means of experimental testing and numerical simulations. However, the behaviour of these columns under biaxial bending has been scarcely investigated, in fact, a very limited number of experimental tests are available for this loading situation. Additionally, the current provisions in EN1994-1-1 for biaxial bending need to be revised, in order to be aligned with the new methods that are being proposed for the new generation of Eurocodes. This paper presents the outcome of a numerical investigation on the load-bearing capacity of slender concrete-filled steel tubular columns subjected to biaxial bending. The focus is on creating and validating a numerical model for room temperature that can predict the behaviour of this type of columns under biaxial bending, which may be used for evaluating the current design guidelines in EN1994-1-1. The numerical model is validated by comparison against experimental tests from the literature, proving that it predicts the ultimate load of slender columns with good accuracy. Different eccentricities about the minor and major axis and different moment ratios are considered, so that this investigation contains cases for both uniaxial and biaxial bending. With the help of this numerical model, the experimental results are extended to generate more cases, in order to assess the accuracy of the current provisions in EN1994-1-1 for concrete-filled steel tubular columns subjected to biaxial bending.
Investigations on global buckling behaviour of concrete-filled double-skinned steel tubular columns
(Editorial Universitat Politècnica de València, 2018-06-05) Sulthana, U. Mashudha; Jayachandran, S. Arul
[EN] Concrete-Filled Double-skinned Steel Tubular columns (CFDST) are proved to possess exceptional structural resistance in case of fire and multi-hazard situations. This superior quality of CFDST makes it preferable in long column applications. However, studies on the long column behaviour of CFDST is very few, and their results are not in line with the behaviour of CFST long columns. Whereas, several researches on stub column CFDST shows that, the axial compression behaviour of CFDST is similar to CFST. In this paper, selected results (4 numbers of circular CFDST specimens) from a large test data is presented. Axial compression behaviour of long column CFDST specimens is studied, with non-dimensional slenderness λ around 1.0, and hollowness ratio as the governing parameter for study. Test results namely, axial load carrying capacity, axial deformation and lateral deflection are presented in this paper. Numerical models are also developed and validated with the experimental results, to carry out more parametric studies. Further, the experimental axial capacity values are compared with modified capacity equations from EC4 and AISC. Results show that extended EC4 and AISC equations gives conservative predictions for CFDST column even in the long column range. Moreover, the initial imperfections in the specimen and their corresponding boundary conditions for load application, are found to be governing parameters in long column buckling study.
Finite element analysis of the flexural behavior of square CFST beams at ambient and elevated temperature
(Editorial Universitat Politècnica de València, 2018-06-05) Javed, Muhammad; Ramli Sulong, Nor Hafizah; Khan, Niaz; Kashif, Sardar; University of Malaya, Kuala Lumpur
[EN] This paper presents the finite element (FE) analysis and modeling of square concrete-filled steel tube (CFST) members subjected to a flexural load at ambient and elevated temperature. The commercial FE tool ANSYS was used in the 3D modeling taking into consideration material and geometric non-linearities. The developed FE model can accurately predict the ultimate moment capacity of the square CFST members subjected to flexural loads and fire resistance time. A parametric study is conducted using the verified FE model to study the effect of the compressive strength of infilled concrete and the yield strength of the steel tube on the flexural behavior of the square CFST members. The ultimate bending capacity of the CFST members increases by up to 27% when the yield strength of the steel tube increases from 210 MPa to 400 MPa while its fire resistance time decreases. For a D/t ratio equal to 30, the flexural capacity increases by 20% when the compressive strength of the infilled concrete increases from 60 MPa to 100 MPa, while it shows increase in fire resistance time.
Analysis and behavior of high-strength rectangular CFT columns
(Editorial Universitat Politècnica de València, 2018-06-05) Lai, Zhichao; Varma, Amit
[EN] The current AISC Specification (AISC 360-16) specifies the material strength limits for concrete-filled steel tube (CFT) columns. According to AISC 360-16, the steel yield stress (Fy) for CFT columns should not exceed 525 MPa, and the concrete compressive strength (f’c) should not exceed 70 MPa. CFT columns are classified as high strength if either Fy or f’c exceeds these specified limits, and are classified as conventional strength if both Fy and f’c are less than or equal to the limits. Due to lack of adequate research and comprehensive design equations, AISC 360-16 does not endorse the use of high-strength materials for CFT columns. This paper makes a contribution towards addressing this gap using a two-step approach. The first step consists of compiling an experimental database of high-strength rectangular CFT column tests in the literature and evaluating the possibility of extending the current AISC 360-16 design equations to high-strength rectangular CFT columns. The second step consists of developing and benchmarking detailed 3D nonlinear finite element models for predicting the behavior of high-strength CFT columns from the database. The benchmarked models are being used to perform comprehensive parametric studies to address gaps in the database and propose design equations for high-strength rectangular CFT members, which will be part of a future paper.
Experimental investigation on the bamboo-concrete filled circular steel tubular stub columns
(Editorial Universitat Politècnica de València, 2018-06-05) Gan, Dan; Zhang, Tao; Zhou, Xuhong; He, Ziqi
[EN] Concrete-filled steel tubes have been widely used all over the world due to their superior structural behaviour. To promote the use of ecofriendly materials and to reduce the use of concrete, this paper presents an innovative type of composite column, which can be referred as bamboo-concrete filled steel tubes. In this kind of column, concrete filled in the space between the external steel tube and the inner raw moso bamboo. Bamboo-concrete filled steel tubes inherit the merits of concrete-filled steel tubes such as high load-bearing capacity and ductility performance. Besides, global buckling behaviour of a bamboo column due to its relatively large slenderness can be significantly improved, and the bamboo column with nodes could provide confinement to the infilled concrete. This paper investigated the composite effect of bamboo-concrete filled steel tubular stub columns subjected to axial compression. In addition, concrete-filled double-skin steel tubular stub columns and hollow concrete-filled steel tubular stub columns were also tested for comparison. The main experimental parameter considered was the diameter-to-thickness ratio (D/t) of steel tube. Test results indicated that the composite columns with moso bamboo pipe as inner core elements showed better ductility than the hollow concrete-filled steel tubular stub columns. The bearing capacity and ductility visibly increased with decreasing of the D/t ratio.
Push-out tests on demountable shear connectors of steel-concrete composite structures
(Editorial Universitat Politècnica de València, 2018-06-05) Kozma, Andras; Odenbreit, Chirstoph; Braun, Matthias; Veljkovic, Milan; Nijgh, Martin; Research Fund for Coal and Steel
[EN] The deconstruction of steel-concrete composite structures in buildings and the later separation of the materials is a labour- and cost intensive work. This is due to the fact, that the shear studs are welded on the steel beam, and a large amount of cutting work gets necessary. As a result, recycling is difficult and the potential for reusing entire elements is lost. The carbon footprint of composite structures could be decreased by the application of the principles of “design for deconstruction and reuse”. This paper presents a study with its respective laboratory experiments on demountable shear connectors that facilitate recyclability and even offer the potential for reusing elements in their entirety. In the Laboratory of Steel and Composite Structures of the University of Luxembourg 15 push-out tests have been carried out using different bolted connection systems suitable for multiple uses in order to verify their performance characteristics by means of shear strength, stiffness, slip capacity, ductility and ability of demounting. The investigated systems included pre-stressed and epoxy resin injection bolts, solid slabs and composite slabs with profiled decking. The results showed that the tested demountable shear connections could provide higher shear resistance than conventional shear connections in some cases. The connection failure happened in the bolts, while there was no or minor visible damage observed on the connected members. Most of the tested connections could fulfil the ductility requirement given by Eurocode 4. The application of epoxy resin in the hole clearance resulted in lower slip capacity. The outcome will provide an important basis for the calibration of the forthcoming enhancement and numerical simulation of the demountable shear connections. The failure behaviour, the observed damages and the resulting ability of the elements for later re-use are discussed in detail.
Sustainable steel and composite constructions for multifunctional commercial buildings
(Editorial Universitat Politècnica de València, 2018-06-05) Stroetmann, Richard; Hüttig, Lukas
[EN] Rising cost pressures and the prospect of quick returns have led to an increase in mono functional buildings since the 1970s. These prevent the adaptation to changing user requirements with little monetary outlay. Lack of marketability, increasing vacancy and early demolition are often the consequences. Main objective of the AIF/FOSTA research project P1118 is to develop planning recommendations for multifunctional usable buildings. Adaptability to changing needs will increase marketability and value stability as well as extend the lifetime of the buildings. This not only increases the economy but also the resource efficiency. First of all, the paper explains the ecological and economic requirements for modern buildings, which are based on current certification systems. In this context, the expected lifetime of primary and secondary building components are also dealt with. Subsequently, relevant types of use as well as requirements for essential building parameters are presented. In a comparison, the ecological expenses and costs are assessed for four selected composite structures. For the multifunctional building structures an extension of lifetime is considered and the environmental and monetary impacts are assessed. Furthermore, the influence of the structure on the building foundations is analysed. The investigations present the effects of the building masses on the foundations for two different soil conditions. Finally, the investigations show that variable usable buildings with a longer lifetime lead to a better sustainability.
Deconstructable Flush End Plate Beam-to-Column Composite Joints: Component- Based Modelling
(Editorial Universitat Politècnica de València, 2018-06-05) Bradford, Mark; Ataei, A.; Liu, X.; Australian Research Council
[EN] Within a paradigm of designing building structures for their end-of-life deconstruction, thispaper addresses flush end plate beam-to-column composite joints that may be dis-assembledand reused elsewhere. The joints consist of steel beams bolted to steel columns, and these aremade composite over the joint with precast concrete slabs attached to the top flange of thesteel beams with post-tensioned high strength bolted shear connectors installed in clearanceholes. Joints of this type experience partial shear connection, and accordingly their designneeds to incorporate this effect. Experimental work reported elsewhere by the authors showsthat a structural system of this type may indeed be deconstructed, even when loaded beyondthe serviceability limit state, and that the moment-rotation response is both robust andductile. A numerical modelling using ABAQUS software is introduced in the paper, and theresults of this are used identify the parameters most influential in the structural response,and to propose equations for the initial stiffness, moment capacity and rotation capacity of ajoint. These equations are consistent with the component-based representation of theEurocode 4 and draft Australian AS2327 composite structures standard.
Horizontal push out tests on a steel-yielding demountable shear connector
(Editorial Universitat Politècnica de València, 2018-06-05) Feidaki, Eliza; Vasdravellis, George
[EN] The most common type of a steel concrete composite beam is the one using conventional welded headed studs to connect the top flange of a steel beam to the concrete slab. However, the monolithic structure between the headed studs and the concrete slab prevents the deconstruction of the beam. More sustainable solutions in construction can be achieved by developing demountable connections which allow for fully deconstruction and reuse of all structural systems. This paper presents a novel demountable shear connector for use in steel concrete composite beams in conjunction with precast hollow core slab units. The demountable connection proposed has the advantages of minimal use of in situ concrete required only in specific regions, increased ductility due to the unique shape of the shear connector and since it is not embedded in in situ concrete, it facilitates the deconstruction procedure. Ten horizontal push out tests aiming at investigating the structural performance of the demountable shear connector were carried out. The strength of the connection is predicted using simple mechanics based on plastic beam analysis. The experimental results showed that the proposed demountable shear connector can achieve increased strength depending on the geometric characteristics of the connector, a ductile slip-load curve and a very high slip capacity.
Punching Shear Mechanism Based Design of Concrete-Filled CHS T-Joints under In-Plane Bending
(Editorial Universitat Politècnica de València, 2018-06-05) Xu, Fei; Chan, Tak-Ming; Chen, Ju
[EN] The in-plane bending behaviour of concrete-filled circular hollow section (CHS) T-joints was examined in this paper. The main failure mode, the punching shear of the chord-wall, was observed from the test of four large-scale joints with the diameter ratio of brace to chord (β) ranging from 0.44 to 0.85. The tube-wall deformation was measured to assess the governing failure mode of the composite joints. Complementary finite element (FE) methodology was verified against the experimental findings and the validated FE models were used to further investigate the mechanical behaviour and the design methodology. The feasibility to apply a fracture criterion in the material-level to a large-scale structural simulation was evaluated. The validated FE modes could successfully capture the tube-wall fracture initiation and propagation. Based on both experimental and numerical investigations, it was shown that the capacity of composite joints was governed by the ultimate strength limit, i.e. punching shear strength, due to the infill concrete that mitigated both inward and outward deformation on the compressive and tensile sides, respectively. The analytical model was established to reveal the composite actions between the tube and the inner concrete, and to elaborate the development of the flexural section-resistance. Finally, the design equation was proposed and could well predict the moment capacity.
Experimental study of the force transfer mechanism in transition zone between composite column and reinforced concrete column
(Editorial Universitat Politècnica de València, 2018-06-05) Dragan, Dan; Plumier, Andre; Degee, Herve
[EN] The current EN 1992 provides structured information related to the design of reinforced concrete columns or reinforced concrete column beam connections. On the other hand, EN 1994 gives enough information on the design of composite columns but none of the current codes provide details about a possible transfer zone in the case of usage of RC and composite column solution. The current study tends to fill the gap between these two norms. In the current experimental campaign, carried out in the frame of the European research program SmartCoCo, it is presented as a calibration method for a tentative design method which has been elaborated by one of the authors based on theoretical strut and tie reasoning. The objective of the current paper is to present the results of the experiments and aims to validate the theoretical approach for calculating the force transfer mechanism in the transfer zone. The experimental campaign comprises of 4 columns and 4 column-beam connections, all of them being composed by a RC part and a composite. The tests are performed on vertical column, simply supported with a width of 350mm, length of 380 mm and a height of 3850 mm with a regular concrete quality (C25/30). This contribution describes the test specimens, summarizes their design, presents a selection of the most relevant results from analog and digital measurements and a short interpretation of the obtain results. We concluded from this set of tests that the new design method is able to explain the force transfer mechanism with a good accuracy and can therefore be considered as a suitable solution for designing practical cases.
Post-fire mechanical properties of high strength steels
(Editorial Universitat Politècnica de València, 2018-06-05) Li, Hai-Ting; Young, Ben
[EN] High strength steels are becoming increasingly attractive for structural and architectural applications due to their superior strength-to-weight ratio which could lead to lighter and elegant structures. The stiffness and strength of high strength steels may reduce after exposure to fire. The post-fire mechanical properties of high strength steels have a crucial role in evaluating the residual strengths of these materials. This paper presents an experimental investigation on post-fire mechanical properties of cold-formed high strength steels. A series of tensile coupon tests has been carried out. The coupon specimens were extracted from cold-formed square hollow sections with nominal yield stresses of 700 and 900 MPa at ambient temperature. The specimens were exposed to various elevated temperatures ranged from 200 to 1000 °C and then cooled down to ambient temperature before tested to failure. Stress-strain curves were obtained and the mechanical properties, namely, Young’s modulus, yield stress (0.2% proof stress) and ultimate strength, of the cold-formed high strength steel materials after exposure to elevated temperatures were derived. The post-fire retention factors that obtained from the experimental investigation were compared with existing predictive equations in the literature. New predictive equations are proposed to determine the residual mechanical properties of high strength steels after exposure to fire. It is shown that the proposed predictive equations are suitable for both cold-formed and hot-rolled high strength steel materials with nominal yield stresses ranged from 690 to 960 MPa.

Examinar

Examinando 12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018 por Fecha de publicación

Resultados por página

Opciones de ordenación