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See detailVerification of analytical and numerical tools - Deliverable D.5b - Robustimpact
Hoffmann, Nadine; Kuhlmann, Ulrike; Vanvinckenroye, Hélène ULg et al

Report (2016)

The numerical recalculation performed on the slab, beam and joint tests as well as the analytical recalculation of these tests have been employed as support for the experimental investigations represented ... [more ▼]

The numerical recalculation performed on the slab, beam and joint tests as well as the analytical recalculation of these tests have been employed as support for the experimental investigations represented within the previous chapter. In particular, numerical and analytical analysis have been performed to design the experimental test and the test setup for the symmetric and the asymmetric 3D test performed by UTRE. For the 2D-frame tests a numerical simulation was performed and the analytical model was validated. In addition to the recalculation of the experimental investigations on composite joints some parameters were varied in order to evaluate the influence on the behavior of the composite joints. Furthermore an analytical approach to predict the response of joints subjected to M-N-loading was investigated. In addition, analytical calculations have been performed in order to predict the results of the static and dynamic experimental tests. [less ▲]

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See detailDetailed results of the experimental tests - Deliverable D.5a - Robustimpact
Hoffmann, Nadine; Kuhlmann, Ulrike; Vanvinckenroye, Hélène ULg et al

Report (2016)

At the Institute for Steel Structures crash tests on columns were carried out to investigate the dynamic response of the member during the impact as well as the dynamic interaction of the member with the ... [more ▼]

At the Institute for Steel Structures crash tests on columns were carried out to investigate the dynamic response of the member during the impact as well as the dynamic interaction of the member with the surrounding structure. The tests' campaign planned by the Università degli Studi di Trento comprises of: - two full-scale tests on 3D specimens representative of the reference buildings; From two reference structures selected as cases study two representative substructures characterised by the same overall dimensions but by a symmetric and an asymmetric configuration (i.e., column layout), respectively, have been identified. The substructures, built in laboratory, are tested reproducing the collapse of a central column. The aim of the tests is to investigate the influence of the biaxial membrane effect associated with the concrete slab in a framed structure when the collapse of a column happens. - 20 tensile tests on T-stubs related to the beam-to-column joint adopted in the reference structures and in the full-scale specimens. T-stubs associated to both the column (10 specimens) and the end-plate (10 specimens) are tested. The tests are performed at two different loading speeds aiming at investigating the influence of strain rate effects on the joint performance, with particular reference to the deformation capacity. As a reference, also quasi-static tests are planned. At the Institute of Structural Design experimental tests were carried out investigating the behaviour of 2D-frames under a column loss. In addition the behaviour of composite joints under high speed loading was examined. Within the framework of the project, two tests on composite frames were tested as well as four tests on composite joints. The 2D substructure tests planned at USTUTT have the objective to evaluate the benefit of the concrete slab compared to the behaviour of the composite frame structure concerning the development of a membrane effect. For this purpose, the results of the composite frame tests will be compared to the 3D substructure tests performed at UTRE. Therefore, the test specimens of the 2D substructure tests are adapted to the 3D substructure tests. In order to compare also the results of the composite joint tests to the behaviour of the frames and to observe the influence of the joints on each other the test specimens for the joint tests are also adapted to the frame tests. Experimental impact tests were planned at the University of Liege (ULg): 22 tests on beam-to-column joints with 5 different joint configurations and 22 tests on column base joints with 4 different joint configurations. One of the objectives of the performed study was to propose realistic joints and column bases which could fit with the laboratory facilities of ULg, what induced a downscaling of the dimension of the members in comparison to the dimension of the ones met in the reference building. With the designed specimens, it is possible to investigate the response of different joint components under impact loading, for different levels of energy (small, medium and high levels), and to compare this response to the one obtained through a static test to highlight the dynamic effects. These static tests are performed for each type of specimens and will be used to clearly determine the different level of energy to be used for the impact tests. The general test setup for all tests was derived in Work Package 3 and can be found in the deliverable D.4.1 [18] of the project. [less ▲]

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See detailSimplified equivalent static approach and results for deriving structural requirements - Deliverables D.11 and D.12 - Robustimpact
Demonceau, Jean-François ULg; D'Antimo, Marina ULg; Huvelle, Clara et al

Report (2016)

Deliverable 11 and 12 have been merged in the present document which can be seen as the main outcome of the activities conducted with Work Package 9 of the Robustimpact project. Section 2 presents first ... [more ▼]

Deliverable 11 and 12 have been merged in the present document which can be seen as the main outcome of the activities conducted with Work Package 9 of the Robustimpact project. Section 2 presents first the sophisticated numerical investigations conducted on a reference structure subjected to impacts of vehicles. Then, Section 3 presents in details the simplified analytical models/tools developed within the present project to predict the response of a structure (or a part of a structure) further to the impact of a vehicle. With the presented models, it is demonstrated that an accurate prediction of the structural results may be obtained and that all the parameters influencing this response are mastered. Section 4 introduces the different parametric studies which have been conducted (partly using the models/tools presented in Section 3) on 2D and 3D steel and composite structures or on composite floors. Finally, Section 5 highlights the structural requirements which can be proposed as an outcome of the performed investigations. Through this document, it is demonstrated that the different objectives of Work Package 9 have been reached in the framework of this project. [less ▲]

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See detailDesign guidlines - Deliverable D.13 - Robustimpact
Charlier, Marion; Hanus, François; Vassart, Olivier et al

Report (2016)

The present document details the design guidelines which emanates from the RobustImpact project. The reasoning used is depicted below in Figure 1-1. The first step is to define the impact scenario and its ... [more ▼]

The present document details the design guidelines which emanates from the RobustImpact project. The reasoning used is depicted below in Figure 1-1. The first step is to define the impact scenario and its key parameters. Then the impact can be characterized as a hard impact or as a soft impact. The first option assumes that the kinetic energy of the impactor is absorbed by the impactor itself while the second option assumes that the kinetic energy of the impactor is mainly absorbed by the column, thus leading to plastic deformations and the activation of geometrical non-linear effects in the column. If the soft impact is considered, the buckling resistance of the column must be examined in order to evaluate if the impacted column shows sufficient residual resistance after the impact. If this is not the case, the structure will resist if it is able to sustain the load initially carried by the impacted column by redistributing it in the damaged structure, i.e. if it is able to activate alternative load path. The resistance brought by other structural elements will then be evaluated. If the impacted column is a peripheral column, the yield line theory is used to evaluate the resistance of both slab and beams. In case of a central column, Bailey’s method evaluating the slab resistance taking into account the membrane effect is used to determine the contribution of the slab. The contribution of the beams is then quantified by evaluating the corresponding P-u curve. All the methods have been validated using FEM softwares. Since the project concerns structures whose columns are impacted by vehicles, the accidental load combination must be considered. In addition, the yield strength of the steel should be considered as 𝑓𝑦,𝑑𝑦𝑛= 𝜇.𝑓𝑦> 𝑓𝑦 . Indeed was proved than the steel mechanical properties are better under dynamic loading. Nevertheless, there is for the moment no available quantification for the majoring coefficient that should apply to 𝑓𝑦 : this could be done realizing tests. [less ▲]

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See detailDesign report of the specimens for all the experimental analyses - Deliverable D.4.1 - Robustimpact
Hoffmann, Nadine; Kuhlmann, Ulrike; Huvelle, Clara et al

Report (2016)

The present report focuses on the design of the experimental analysis that are going to be performed within the ROBUSTIMPACT project (Grant Agreement Number: RFSR-CT-2012-00029). The project focuses on ... [more ▼]

The present report focuses on the design of the experimental analysis that are going to be performed within the ROBUSTIMPACT project (Grant Agreement Number: RFSR-CT-2012-00029). The project focuses on the behavior of composite steel and concrete framed buildings against accidental actions. Within the project, several experimental analyses are going to be performed spanning from the local to the global behavior. The report is divided in 4 parts, each one describing the preliminary work of each partner of the project. In particular:  Part A reports the work performed by USTUTT (University of Stuttgart) including the design of four experimental tests on composite joints and two experimental tests on composite frames. In particular, the composite joints will be investigated in order to better understand the behavior in terms of activation of catenary actions. The tests on composite frames are performed investigating the influence of the high speed loading and strain rate effects on the deformation capacity of these structures.  Part B reports the work performed by ULg (University of Liege) including the design of 44 experimental impact tests on beam-to-column joints and column base joints. With these tests will be possible to investigate the response of different joint components under impact loading for different level of energy.  Part C reports the work performed by UTRE (Università degli Studi di Trento) including the design of the case study reference structures and the design of the experimental tests. In particular, two 3D full scale tests will be performed by simulating to total loss of the impacted column in order to investigate the redundancy of the 3D slab system in terms of activation of membrane effects.  Part D reports the work performed by RWTH (University of Aachen) including the design of six crash tests on columns that are going to be performed in order to investigate the residual strength of the damaged member after the impact. The aim is to determine the response of the member during the impact as well as the dynamic interaction of the member with the surrounding structure. [less ▲]

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See detailRobust impact design of steel and composite building structures
Hoffman, Nadine; Kuhlmann, Ulrike; Demonceau, Jean-François ULg et al

in Proceeding of the IABSE Workshop - Safety, Robustness and Condition Assessments of Structures (2015, February)

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See detailRobust impact design of steel and composite building structures: the alternate load path approach
Hoffmann, Nadine; Kuhlmann, Ulrike; Demonceau, Jean-François ULg et al

in Proceeding of the IABSE Workshop - Safety, Robustness and Condition Assessments of Structures (2015, February)

Vulnerability of structures to progressive collapse and mitigation of the effects of local damages are topics widely discussed. The studies worldwide carried out allowed identifying different design ... [more ▼]

Vulnerability of structures to progressive collapse and mitigation of the effects of local damages are topics widely discussed. The studies worldwide carried out allowed identifying different design strategies. However, specific knowledge is still limited and this gap is apparent in codes of practice. A European project focusing on robustness of steel and steel and concrete composite structures regarding the effects of impact recently started combining the 2 methods of residual strength and alternate load path. In the framework of the project activities, the Authors aimed their studies on the redundancy of the structure through slab-beam-systems and ductile joint as well as on the local behaviour of the impacted members. For this analytical, numerical and experimental investigations have been planned and executed. The paper describes the experimental activities related to the investigations on the structural redundancy and presents the preliminary test outcomes. [less ▲]

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See detailHigh strength steel in seismic resistant building frames (HSS-SERF)
Dubina, Dan; Vulcu, Cristian; Stratan, Aurel et al

Book published by Commission Européenne (2015)

The aim of “HSS-SERF” project was to investigate and evaluate the seismic performance of dual-steel building frames, realized from two different steel grades: Mild Carbon Steel (MCS) and High Strength ... [more ▼]

The aim of “HSS-SERF” project was to investigate and evaluate the seismic performance of dual-steel building frames, realized from two different steel grades: Mild Carbon Steel (MCS) and High Strength Steel (HSS). A comprehensive set of dual-steel frames (moment resisting, concentrically and eccentrically braced) were designed, which allowed the identification of realistic member sizes for both MCS and HSS components. Several practical solutions for bolted and welded beam-to-column joints were identified and designed. Further, an extensive numerical program was carried out for the seismic performance evaluation of frames. The ductility and over-strength demands, and q-factors associated with different performance levels were evaluated. Furthermore, experimental and numerical investigations were carried out on joint assemblies and components. Guidelines were elaborated for the conceptual design and PBD of dual-steel frames under seismic actions, and the technical and economic efficiency of dualsteel structures vs. conventional ones were finally evaluated. The main outcomes of the project consist in: (i) development and characterisation in terms of global ductility and over-strength demands of dual-steel frames with composite columns (innovative solutions in European context); (ii) development of design recommendations; (iii) proposal of innovative solutions for beam-to-column joints with composite columns; (iv) recommendation for weld details and appropriate component method design approaches; (v) evaluation of technical and economic efficiency of the dual-steel approach. [less ▲]

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See detailRobustimpact - Drawings for producing the test specimens - Deliverable 4.2
Hoffman, Nadine; Kuhlmann, Ulrike; Huvelle, Clara ULg et al

Report (2014)

Within the RFCS project RobustImpact an experimental campaign, aimed at investigating the behaviour of framed steel and concrete composite structures under accidental loading conditions, was planned. The ... [more ▼]

Within the RFCS project RobustImpact an experimental campaign, aimed at investigating the behaviour of framed steel and concrete composite structures under accidental loading conditions, was planned. The residual strength of the damaged member after an impact as well as the dynamic interaction of the member with the surrounding structure will be experimentally investigated. The activation of alternate load paths will be also studied through tests on 3D slab and 2Dbeam systems. Additional tests on composite joints, beam-to-column joints, column bases and T-stub tests under high speed loading and impact loading will contribute at investigating the influences of strain rate effect on the deformation capacity of the connections.This document collects the drawings prepared by the above mentioned partners for producing the test specimens. [less ▲]

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See detailRobusimpact - Design report of the specimens for all the experimental analyses - Deliverable 4.1
Hoffman, Nadine; Kuhlmann, Ulrike; Huvelle, Clara ULg et al

Report (2014)

The present report focuses on the design of the experimental analysis that are going to be performed within the ROBUSTIMPACT project (Grant Agreement Number: RFSR-CT-2012-00029). The project focuses on ... [more ▼]

The present report focuses on the design of the experimental analysis that are going to be performed within the ROBUSTIMPACT project (Grant Agreement Number: RFSR-CT-2012-00029). The project focuses on the behavior of composite steel and concrete framed buildings against accidental actions. Within the project, several experimental analyses are going to be performed spanning from the local to the global behavior. [less ▲]

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See detail“State-of-problem report prepared for the TC11 meeting held in Valencia on October 2012”
Demonceau, Jean-François ULg; Hjiaj, Mohammed; Aribert, Jean-Marie et al

Report (2012)

The present document summarises recent studies and developments investigating the behaviour of composite frames, for discussion within TC11 Committee. Also, possible aspects to be investigated in future ... [more ▼]

The present document summarises recent studies and developments investigating the behaviour of composite frames, for discussion within TC11 Committee. Also, possible aspects to be investigated in future are identified. The document is organised as follows: • First, the global frame behaviour is considered in § 2; • Then, the structural members which can be met in a composite structure, i.e. the composite slabs, the composite beams, the composite columns and the composite joints, are considered in separate paragraph from § 3 to § 6; • A specific paragraph is also dedicated to the possible long term effects on composite members (§ 7); • Finally, a conclusion is drawn in § 8, summarising recent improvements in the knowledge about composite frame design and possible further developments. A first draft of this document was presented at the TC11 meeting held in Liège on March 2010. The present document is an updated draft to be discussed at the TC11 meeting held in Valencia on october 2012. Remark: the aspects related to the response of composite structures subjected to seismic or fire actions are not reported here as they are covered by other more “transversal” technical committees of ECCS (TC3 for the fire and TC13 for the seismic action). [less ▲]

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See detailAnforderungen an Stahl- und Verbundknoten bei Stützenausfall in einem Rahmentragwerk
Kuhlmann, Ulrike; Rölle, Lars; Jaspart, Jean-Pierre ULg et al

in Stahlbau (2010), 8(August 2010), 565-579

Local failure in a structure (e.g. sudden column loss due to impact or explosion) could lead to progressive collapse propagation of the global structural system resulting in a total collapse. To avoid ... [more ▼]

Local failure in a structure (e.g. sudden column loss due to impact or explosion) could lead to progressive collapse propagation of the global structural system resulting in a total collapse. To avoid progressive collapse initiated by local damage a redistribution of force from the damaged part of the structure has to be enabled by alternate load path. Activation of alternate load paths by change of the bearing mechanism from pure bending state to more or less pure membrane state is a measure but only possible by allowing large global deformations resulting in high de-formation requirements for the joints. In the frame of a European RFCS research project ductile joint solution have been developed to improve the robustness as characteristic of the structure. Main focus for the joint design was given to obtain the required deformation capacity for acci-dental design situations mainly from the joints and cause at the same time only less additional material and fabrication costs for the joints. As a result deformable and partial-strength joint solution has been chosen. Objective within the project was to determine requirements of the joints concerning deformation capacity as well as M-N-resistance to enable the activation of catenary action for the load case notional column removal. [less ▲]

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See detailRobust structures by joint ductility
Kuhlmann, Ulrike; Rolle, Lars; Jaspart, Jean-Pierre ULg et al

Book published by European Commission (2008)

In view of recent disasters and their immense economical and human consequences more and more focus is given not only on the safety of structures - to reduce the risk for the life of people by collapse ... [more ▼]

In view of recent disasters and their immense economical and human consequences more and more focus is given not only on the safety of structures - to reduce the risk for the life of people by collapse even under exceptional loading – but on minimizing the disastrous results and to enable a quick rebuilding and reuse. One crucial mean to achieve this aim is the design of redundant robust structures. Robustness prevents the collapse of the total structure when only parts of the structure are damaged or destroyed. To avoid progressive failure, redundant structures with inherent sufficient ductile behaviour allowing deformations when a local failure occurs, have to be built. Redundancy can be achieved by allowing force redistribution within a structural system. Therefore the single sections and joints have to be especially designed and optimized, not necessarily requiring additional fabrication costs. But until now no specific rules for robustness by ductile joints exist. The aim of the present project is to define general requirements for ductile joints as part of a structural system subjected to exceptional unforeseen loading. [less ▲]

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See detailInteraction of global and local buckling in welded RHS compression members
Degée, Hervé ULg; Detzel, Annette; Kuhlmann, Ulrike

in Journal Of Constructional Steel Research (2008), 64(7-8), 755-765

This paper presents the results of a research project analysing some aspects of the stability failure of thin-walled compression members that are likely to exhibit combined global and local buckling. In ... [more ▼]

This paper presents the results of a research project analysing some aspects of the stability failure of thin-walled compression members that are likely to exhibit combined global and local buckling. In particular, the influence of various imperfections, namely residual stresses due to welding and local as well as global geometrical defects, on the load-carrying capacity was Subjected to detailed experimental and numerical investigations. The insights obtained into the structural behaviour led to a proposal for modification of the non-dimensional slenderness used in the global buckling verification, and to the recommendation of a shift from the Currently applied European buckling curve to a more favourable one in the case of non-stiffened members with welded box sections subjected to pure compression. (C) 2008 Elsevier Ltd. All rights reserved. [less ▲]

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See detailRobustness - Robust structures by joint ductility
Kuhlmann, Ulrike; Rölle, Lars; Jaspart, Jean-Pierre ULg et al

in Wald, F.; Mazzolani, F.; Byfield, M. (Eds.) et al Urban Habitat Constructions under Catastrophic Events (2007, March 30)

In view of recent disasters and their immense economical and human consequences more and more focus is given not only on the safety of structures - to reduce the risk for the life of people by collapse ... [more ▼]

In view of recent disasters and their immense economical and human consequences more and more focus is given not only on the safety of structures - to reduce the risk for the life of people by collapse even under exceptional loading – but on minimizing the disastrous results and to enable a quick rebuilding and reuse. One crucial mean to achieve this aim is the design of redundant robust structures. Robustness prevents the collapse of the total structure when only parts of the structure are damaged or destroyed. To avoid progressive failure, redundant structures with inherent sufficient ductile behaviour allowing deformations when a local failure occurs, have to be built. Redundancy can be achieved by allowing force redistribution within a structural system. Therefore the single sections and joints have to be especially designed and optimized, not necessarily requiring additional fabrication costs. But until now no specific rules for robustness by ductile joints exist. The aim of the present project is to define general requirements for ductile joints as part of a structural system subjected to exceptional unforeseen loading. [less ▲]

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