12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018https://riunet.upv.es:443/handle/10251/1072802024-03-29T08:29:22Z2024-03-29T08:29:22ZHeaded studs close to concrete edge under pull-outPascual, Ana MariaKuhlmann, UlrikeRuopp, JakobStempniewski, L.https://riunet.upv.es:443/handle/10251/1099902023-11-21T11:40:44Z2018-10-10T07:04:44ZHeaded studs close to concrete edge under pull-out
Pascual, Ana Maria; Kuhlmann, Ulrike; Ruopp, Jakob; Stempniewski, L.
[EN] The capacity of the headed studs when they are close to the edge may be limited by the splitting forces in the concrete. In the Eurocode 4 Part 2 Annex C the shear capacity under this particular arrangement of the studs, which is directly dependent on the distance to the edge, is formulated. In addition, the geometrical restrictions to prevent the failure by pull-out of the studs are also given in clause C1 (2). These rules are based on push-out tests for the edge position where tension forces in the lying studs spread over the width of the specimen in this unfavorable way. Nonetheless, the current limits lead to extremely long studs and represent a severe restriction, and on the other hand, it is still an open question whether in real buildings or bridge girders the tension stresses that produce the pull-out appears in the same way as in the push out tests. In this paper the revision of these restrictions is presented together with a research for the alternative use of EN 1992-4 plus RFCS Project INFASO for the verification of the tension loads on the studs.
2018-10-10T07:04:44ZMega columns with several reinforced steel profiles – experimental and numerical investigationsBogdan, TeodoraChrzanowski, Maciejhttps://riunet.upv.es:443/handle/10251/1099892023-11-21T11:40:44Z2018-10-10T07:01:03ZMega columns with several reinforced steel profiles – experimental and numerical investigations
Bogdan, Teodora; Chrzanowski, Maciej
[EN] Steel reinforced concrete (SRC) columns are widely used in super high-rise buildings, since they can provide larger load bearing capacity and better ductility than traditional reinforced concrete (RC) columns. Six concrete – encased composite columns were designed based on a typical mega-column of a super high-rise building constructed in China. The specimens are identical in geometrical configurations having as changing parameter the eccentricity ratio of the applied load: every two of the specimens were loaded statically with the eccentricity ratio of 0, 10%, and 15%, respectively. Such columns are however not covered by EN 1994-1-1 [2] (limited to one single encased profile), while AISC 360-16 [8] allows the design of composite sections built-up with two or more encased steel sections, although the way to perform such a design is not detailed. A finite element analysis was conducted as a supplement to the physical tests to provide a deeper insight into the behavior of SRC columns. The experimental campaign has yielded stable test results, suggesting a desirable performance of SRC columns. It is concluded from these experiments that sufficient composite action exists between the concrete and the steel sections for the tested SRC specimens, and that the current code provisions are applicable for the considered configuration, in predicting the flexural capacity of SRC columns when the eccentricity ratio is less than or equal to 15%. The present paper summarizes the principles and an application method for the design of such columns under combined axial compression and bending. The method is based on simplifications provided in EN 1994–1. The validation of the method is made using experimental and numerical results.
2018-10-10T07:01:03ZAnalysis of Fracture Behavior of Large Steel Beam-Column ConnectionsQi, LiangjiePaquette, JonathanEatherton, MatthewLeon, RobertoBogdan, TeodoraPopa, NicoletaNunez, Edurnehttps://riunet.upv.es:443/handle/10251/1099882023-11-21T11:40:44Z2018-10-10T06:58:54ZAnalysis of Fracture Behavior of Large Steel Beam-Column Connections
Qi, Liangjie; Paquette, Jonathan; Eatherton, Matthew; Leon, Roberto; Bogdan, Teodora; Popa, Nicoleta; Nunez, Edurne
[EN] Recently completed experimental steel beam-column connection tests on the largest specimens of reduced-beam section specimens ever tested have shown that such connections can meet current seismic design qualification protocols, allowing to further extend the current AISC Seismic Provisions and the AISC Provisions for Prequalified Connections for Special and Intermediate Steel Moment Frames. However, the results indicate that geometrical and material effects need to be carefully considered when designing welded connections between very heavy shapes. Understanding of this behavior will ease the use of heavier structural shapes in seismic active areas of the United States, extending the use of heavy steel sections beyond their current use in ultra-tall buildings. To better interpret the experimental test results, extensive detailed finite element analyses are being conducted on the entire series of tests, which comprised four specimens with beams of four very different sizes. The analyses intend to clarify what scale effects, at both the material and geometric level, influence the performance of these connections. The emphasis is on modeling of the connection to understand the balance in deformation between the column panel zones and the reduced beam section, the stress concentrations near the welds, the effects of initial imperfections and residual stresses and the validity of several damage accumulation models. The models developed so far for all four specimens have been able to accurately reproduce the overall load-deformation and moment-rotation time histories.
2018-10-10T06:58:54ZAn innovative concrete-steel structural system allowing for a fast and simple erectionLepourry, ClemenceSomja, HuguesKeo, PiseyHeng, PisethPalas, Franckhttps://riunet.upv.es:443/handle/10251/1099872023-11-21T11:40:44Z2018-10-10T06:56:23ZAn innovative concrete-steel structural system allowing for a fast and simple erection
Lepourry, Clemence; Somja, Hugues; Keo, Pisey; Heng, Piseth; Palas, Franck
[EN] In usual concrete buildings, medium to long span slabs can only be achieved by using prestressed beams. However, these elements are heavy, making their handling expensive; the cladding of these beams to vertical elements creates several difficulties, particularly in case of moment resisting frames; at last, their precamber implies a cautious management of the concreting and is a source of defects. Steel-concrete composite beams may offer an alternative, with similar performances. However they are not considered by concrete builders, because specific tools and skills are needed to erect them on site. Moreover usual composite members require a supplementary fire protection, which is costly and unsightly. This article presents an innovative steel-concrete moment resisting portal frame that overcomes these difficulties. It is based on composite tubular columns, and a composite beam made of a U-shaped steel profile used as permanent formwork to encase a concrete beam. This steel-concrete duality of beams allows an erection on site without any weld or bolt by a wise positioning of the construction joints. Moreover, as the resistance to fire is ensured by the concrete beam, the system does not require any additional fire protection. Finally, as only steel elements have to be handled on site, there is no need of heavy cranes. This system has been used to build a research center near Rennes, in France. As it is not covered in present norms, an experimental validation was required. After a detailed description of the structural system, the full-scale tests which have been performed are presented : - A series of asymmetrical push-out tests in order to determine the behaviour and resistance of shear connectors; - One 6-point bending test made to investigate the resistance of the USCHB under sagging bending moment; Two tests of the beam-column joint.
2018-10-10T06:56:23ZImprovement of bearing failure behaviour of T-shaped steel beam-reinforced concrete columns joints using perfbond plate connectorsYoshida, MikihitoNishimura, Yasushihttps://riunet.upv.es:443/handle/10251/1099862023-11-21T11:40:44Z2018-10-10T06:54:01ZImprovement of bearing failure behaviour of T-shaped steel beam-reinforced concrete columns joints using perfbond plate connectors
Yoshida, Mikihito; Nishimura, Yasushi
[EN] For the joints composed of steel beams and reinforced concrete columns, shear failure and bearing failure are the key failure modes. The shear failure indicates stable hysteresis loop without the strength degradation. On the other hand, the bearing failure mode indicates large pinching and strength degration after the attainment of the maximum load.Accordingly, bearing failure in the joints should not be caused in RCS system.To improve the bearing failure behavior of S beam - RC column joint, joint details using perfobond plate connectors were proposed. Perfobond plate connectors were attached on the upper and bottom flanges at right angles to the steel flange. The objective of this study is to clarify the effectiveness of proposed joints details experimentally and theoretically.Six specimens were tested. All specimens were T-shaped planar beam - column joints with 350mm square RC column and S beams with the width of 125mm and the depth of 300mm. The beams were all continuous through the column.Perfobond plate connectors were attached on the bottom flanges at right angles to the steel flange.Three holes were set up in the perfobond plate connectors. The experimental variable was the transverse reinforcement ratio of the joints. The transverse reinforcement ratio of the joints was 0.181% and 0.815%. For each transverse reinforcement ratio of the joints, specimen without the perfobond plate connectors, specimen with the perfobond plate connectors and specimen with the reinforcing bar inserted the hole of perfobond plate connectors were planned.For all specimens, the hysteresis loop showed the reversed S-shape. However, energy dissipation for specimens for specimens with perfobond plate connectors was larger than of specimen without perfobond plate connectors. Bearing strength of specimens with perfobond plate connectors was larger than that of specimen without perfobond plate connectors. From the test results, shear strength of concrete connector a hole was 0.7 times compression strength of concrete.On the other hand, shear strength of inserted reinforcing bar was 1.25 times shear strength of reinforcing bar.Based on the stress transferring mechanism and resistance mechanism of joints proposed by authors, the design formulae of joints with perfobond plate connectors were proposed.The predictions were shown to be in good agreement with the test results.
2018-10-10T06:54:01ZResistance of a steel-concrete hybrid thermal break system to low cycle fatigue under thermal actionsLe Gac, BenoitKeo, PiseySomja, HuguesPalas, Franckhttps://riunet.upv.es:443/handle/10251/1099852023-11-21T11:40:44Z2018-10-10T06:51:07ZResistance of a steel-concrete hybrid thermal break system to low cycle fatigue under thermal actions
Le Gac, Benoit; Keo, Pisey; Somja, Hugues; Palas, Franck
[EN] External insulation is the most widely used technique in Northern and Continental Europe. This technique generates thermal bridges where the building facade has some projecting element like balconies. The thermal requirements of actual standards lead to restore the continuity of the insulation at the interfaces by using thermal break systems (TBS). They are usually made of a box containing the insulation material, and a minimalist structural system able to transmit the shear force and the bending moment from the balcony to the wall. In most cases, structural elements are made of stainless steel, as it is less heat-conducting than normal steel. The paper focuses on a specific TBS, that uses shear keys and steel profiles to ensure the transfer of forces. TBS are also submitted to important horizontal cyclic shear deformations, provoked by the variations of the dimensions of the balconies due to climatic effects. The objective of the study presented in the paper is to show that significant yielding under these cyclic actions can be accepted during service life. First experimental cyclic loading tests have been performed in order to characterize the behaviour of the TBS, as well as its fatigue strength. Then the loading has been defined on the basis of the database of the ECA&D, the European Climate Assessment and Dataset. Finally, the fatigue resistance of the system has been verified. It is shown that the developed TBS can resist to fatigue loading for large lengths of balconies, while exhibiting significant yielding during service life.
2018-10-10T06:51:07ZPull-out Behaviour of Extended Hollobolts for Hollow Beam-Column ConnectionsBin Shamsudin, Mohd FazaulnizamTizani, Walidhttps://riunet.upv.es:443/handle/10251/1099842023-11-21T11:40:44Z2018-10-10T06:49:03ZPull-out Behaviour of Extended Hollobolts for Hollow Beam-Column Connections
Bin Shamsudin, Mohd Fazaulnizam; Tizani, Walid
[EN] The use of structural hollow sections (SHS) as columns in single-storey and multi-storey results in better compression strength, low surface area, architectural attractiveness and high strength to weight ratio. One major constraint when connecting to hollow sections is in accessing and tightening the bolt from the inside of the hollow section. To resolve this issue, full welding is usually applied. But this may suffer from high labour cost, and the potential of low quality welding due to workmanship and varied environmental conditions. Connecting using additional components, such as gusset plates and brackets, helps to ease this problem but lowers aesthetic appeal. To avoid the need to access to the inner face of the column section, new type of fasteners known as blind bolts were introduced. In this paper, experimental and numerical studies were conducted using a new anchored blind bolt known as the Extended HolloBolt (EHB), with the objective of using the component method for predicting joint behaviour within the tensile region. The behaviour of EHB in a group with different connection topologies and configurations was investigated using a total of 36 tests with one row of M16 Grade 8.8 and 10.9 bolts subjected to pull-out loading in tension. The experimental work covers a range of parameters such as bolt gauge, concrete strength, concrete type, bolt embedment depth and bolt class. A finite element model was implemented with good agreement between experimental and simulated load-deflection results, which have a maximum difference of 2.5%, shows that the model is suitable to be used for parametric studies or analytical work in further research on the EHB.
2018-10-10T06:49:03ZBending Moment Capacity of Stainless Steel-Concrete Composite BeamsShamass, RabeeCashell, Katherinehttps://riunet.upv.es:443/handle/10251/1099832023-11-21T11:40:44Z2018-10-10T06:46:59ZBending Moment Capacity of Stainless Steel-Concrete Composite Beams
Shamass, Rabee; Cashell, Katherine
[EN] Stainless steel is increasingly popular in construction owing to its corrosion resistance, excellent mechanical and physical properties as well as its aesthetic appearance. The current paper is concerned with the use of stainless steel in steel-concrete composite beams, which is a new application. Current design codes for steel-concrete composite beams neglect strain hardening in the steel. Whilst this is a reasonable assumption for carbon steel, stainless steel is a very ductile material which offers significant levels of strain hardening prior to failure. Therefore, when current design provisions are applied to stainless steel composite beams, the strength predictions are generally inaccurate. The current study presents a simplified analytical solution that takes into consideration the strain hardening of stainless steel when bending moment capacity is calculated. A finite element model is developed and validated against a number of experimental results for composite beams. The validated numerical model is then used to investigate the accuracy of the proposed analytical solution. It is concluded that simplified analytical solution is reliable and provides a straightforward design tool for practicing engineers who wish to specify this novel construction form in appropriate applications.
2018-10-10T06:46:59ZAnalysis and behavior of high-strength rectangular CFT columnsLai, ZhichaoVarma, Amithttps://riunet.upv.es:443/handle/10251/1099822023-11-21T11:40:44Z2018-10-10T06:44:28ZAnalysis and behavior of high-strength rectangular CFT columns
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.
2018-10-10T06:44:28ZFire performance of concrete-encased CFST columns and beam-column jointsZhou, KanHan, Lin-Hanhttps://riunet.upv.es:443/handle/10251/1092372023-11-21T11:40:44Z2018-10-04T07:29:59ZFire performance of concrete-encased CFST columns and beam-column joints
Zhou, Kan; Han, Lin-Han
[EN] Concrete-encased CFST (concrete filled steel tube) structure is a type of composite structure featuring an inner CFST component and an outer reinforced concrete (RC) component. They are gaining popularity in high-rise buildings and large-span buildings in China nowadays. To date, the behaviour of concrete-encased CFST structures at ambient temperature has been investigated, but their fire performance has seldom been addressed, including the performance in fire and after exposure to fire. This paper summarizes the fire test results of concrete-encased CFST columns and beam-column joints. The cruciform beam-column joint was composed of one continuous concrete-encased CFST column and two cantilevered reinforced concrete (RC) beams. These specimens were subjected to a combined effect of load and full-range fire. The test procedure included four phases, i.e. a loading phase at ambient temperature, a standard fire exposure phase with constant load applied, a sequential cooling phase and a postfire loading phase. The main findings are presented and analysed. Two types of failure were identified, i.e. the failure during fire exposure and the failure during postfire loading. Global buckling failure was observed for all the column specimens. The column specimens with common load ratios achieved high fire ratings without additional fire protection. The concrete-encased CFST columns also retained high postfire residual strength. As for the joint members, beam failure was observed in all cases. The measured temperature-time history and deformation-time history are also presented and discussed. For both the column and joint specimens, the deformation over the cooling phase was significantly greater than that in the standard fire exposure phase.
2018-10-04T07:29:59Z