References of "Phung Ngoc, Dung"
     in
Bookmark and Share    
Full Text
See detailSEISMICALLY RETROFITTING AND UPGRADING RC-MRF BY USING EXPANDED METAL PANELS
Phung Ngoc, Dung ULg

Doctoral thesis (2011)

Reinforced concrete moment resisting frames (RC-MRFs) have been widely used as the main structural resisting systems for over 30 years based on their capacity in resisting both gravity loads and lateral ... [more ▼]

Reinforced concrete moment resisting frames (RC-MRFs) have been widely used as the main structural resisting systems for over 30 years based on their capacity in resisting both gravity loads and lateral forces like winds or earthquakes and on low cost of construction. However, there have been still many existing RC-MRFs not designed according to any modern seismic code. This may lead to some undesired failures under a rather low intensity earthquake. There are several existing retrofitting systems available for seismically retrofitting RC-MRFs, such as steel braces, steel plate or RC shear walls, base isolators…In those, some are able to increase the stiffness, strength, deformation and energy absorbing capacity of the structures and some are able to reduce the influence of the seismic actions on the structure. Despite having advantage in increasing the stiffness and strength for the buildings, the use of bulky systems like RC shear walls to retrofit buildings under seismic actions becomes more limited due to its complication in erection and high costs for foundation. The use of lighter retrofitting systems such as steel braces or shear walls made from steel or aluminium… has been becoming more favourable. Made from sheet steel or various alloys by cutting and simultaneous stretching cold, expanded metal is considered as a macro-foam material. An expanded metal panel (EMP) with rectangular dimensions of 1.25m x 2.5m having many rhomb shape stitches with different geometrical sizes is the popular product. Currently it is employed primarily in the areas of protection (fencing, gates) and architecture. The final goal of this study is to consider a new application different in the field of civil engineering and more specifically that of the earthquake resistance of buildings. The work plan includes two main parts. This first part will set the EMP over existing techniques and see if its use is justified in the context of earthquake resistance. In addition, a more detailed description of the EMP is considered. In this way, the different data required for modelling the new resistance system are known and analyzes, tests and comparisons can be made in order to validate the use of EMP in the context of earthquake resistance. A complete study on pure shear behaviour of EMP under monotonic and quasi-static cyclic loading has been developed including experimental, theoretical and numerical investigations. To apply EMP in seismically retrofitting RC-MRFs, thirty two RC-MRFs have been designed according to two codes EC2 and EC8. The seismic performance of the studied frames has been evaluated using Pushover and NLTH analyses. For the frames designed according to EC2 or EC8 with low ductility, some prominent deficiencies are found, such as incomplete load path or the soft-story failure. Based on the knowledge of deficiencies of the existing frames, many attempts to exploit EMP to seismically retrofit the existing frames have been made. All frames designed according to EC2 and EC8 with Low Ductility Class need to retrofit because they cannot reach the target displacements due to premature failure of beam-column joints. To seismically retrofit them by using EMP, a design procedure based on Direct Displacement Based Design (DDBD) has been proposed. The design is an iterative procedure, starting with the selection of the target displacements at the top based on the results from Pushover analysis. They are usually less than the limit displacements at which RC frames collapse due to crushing of the concrete at beam-column joints. These displacements are also the target ones for the retrofitted frames. The results from design procedure proposed are significantly affected by some typical factors such as selected target displacements and capacity of the existing frames contributing to overall resistance of the retrofitted frames, equivalent viscous damping of the EMP and MRFs as well as geometrical dimensions of the existing frames. The retrofitted design results, assessed by Pushover and NLTH analyses, have indicated that DDDB is a useful tool to design EMP to seismically retrofit the existing frames. With EMP, all retrofitted frames can reach target displacements under design earthquakes without any brittle failure, not like the original frames. However, EMP cannot improve the behaviour of the beam-column joints. Under the earthquakes greater than design ones, failure of the nodes is still observed in all retrofitted frames. The comparison of the seismic performance of the frames before and after being retrofitted has shown that EMP is able to reduce the influence of the earthquake on the original frames by increasing their strength and stiffness and by absorbing the seismic energy. Proposed design procedure of connection between EMP and the frame elements is applicable. This was verified in the experiments when connecting EMP with the steel testing frames. The design approach for the connection is based on Capacity Design, all starting with the maximum resistance of the bars in a rhomb-shape stitch of the EMP and the tension field action developed in the EMP during shear loading. However, it is necessary to perform tests on the connections between EMP and the RC beams and columns. Also, improved practical details can be developed. [less ▲]

Detailed reference viewed: 117 (9 ULg)
Full Text
See detailSEISMICALLY RETROFITTING AND UPGRADING RC-MRF BY USING EXPANDED METAL PANELS
Phung Ngoc, Dung ULg; Degée, Hervé ULg; Plumier, André ULg

Scientific conference (2011, January 15)

Expanded Metal is a second product made from metal sheet by first cuttings, cold-drawing, and finally by being flattened. A research is under way at University of Liege with the aims at determining the ... [more ▼]

Expanded Metal is a second product made from metal sheet by first cuttings, cold-drawing, and finally by being flattened. A research is under way at University of Liege with the aims at determining the mechanical properties of this type of material under seismic excitations. In view of their application to building seismic retrofitting and upgrading, three approaches: analytical models, numerical simulations and experimental investigations, have been used to characterize the mechanic behavior of expanded metal sheets which are monotonically and cyclically loaded in shear. Nonlinear numerical simulations and experimental tests are used to determine the hysteretic behavior of expanded metal shear panels (EMSP), and an analytical model is then proposed, with the aims of using that to study the influence of such EMSP when they are used to retrofit and upgrade reinforced concrete moment resisting frames (RC-MRF). Many RC-MRF are then designed in two cases: (1) in accordance with only Eurocode 2 and (2) in accordance with both Eurocode 2 and Eurocode 8. Capacities of such designed structures are evaluated by using nonlinear static analysis (Pushover) and nonlinear time history analysis under different types of soils and ground motions. The efficiency of using EMSP is evaluated in terms of strength, stiffness and energy dissipation. Additionally, with the presence of EMSP, some unfavorable behavior of RC-MRF under seismic action such as soft story mechanism can be prevented. [less ▲]

Detailed reference viewed: 94 (6 ULg)
Full Text
Peer Reviewed
See detailBehaviour of EMP under shear loadings
Phung Ngoc, Dung ULg; Degée, Hervé ULg; Plumier, André ULg

in Behaviour of EMP under shear loadings- SDSS 2010 (2010)

Experimental and theoretical study of expanded metal panels (EMP) has shown that they are useful for seismically retrofitting reinforced concrete moment resisting frames (RC-MRF). Although this product ... [more ▼]

Experimental and theoretical study of expanded metal panels (EMP) has shown that they are useful for seismically retrofitting reinforced concrete moment resisting frames (RC-MRF). Although this product has merit of strength and ductility, it is at present only used for non-structural applications. There is no guidance existing to help the engineers determine the mechanical properties or to indicate in which field of the structures this product can be used. With the aims at providing quantitative data for these purposes and at introducing a simplified model of EMP working in shear, description and comparison of the results of 22 monotonic and cyclic experiments of 4 profiles of EMP in small and large scale is presented. Numerical approach with FINELG, a nonlinear finite element code developed at University of Liege, is used to calibrate and simulate the tests. A good correlation between tests and numerical simulations is observed. [less ▲]

Detailed reference viewed: 79 (7 ULg)
Full Text
Peer Reviewed
See detailSeismic retrofitting and upgrading reinforced concrete moment resisting frames by using expanded metal shear panels
Phung Ngoc, Dung ULg; Degée, Hervé ULg; Plumier, André ULg

in Seismic retrofitting and upgrading reinforced concrete moment resisting frames by using expanded metal shear panels (2010)

Expanded Metal is a second product made from metal sheet by first cuttings, cold-drawing, and finally by being flattened. A research is under way at University of Liege with the aims at determining the ... [more ▼]

Expanded Metal is a second product made from metal sheet by first cuttings, cold-drawing, and finally by being flattened. A research is under way at University of Liege with the aims at determining the mechanical properties of this type of material under seismic excitations. In view of their application to building seismic retrofitting and upgrading, three approaches: analytical models, numerical simulations and experimental investigations, have been used to characterize the mechanic behavior of expanded metal sheets which are monotonically and cyclically loaded in shear. Nonlinear numerical simulations and experimental tests are used to determine the hysteretic behavior of expanded metal shear panels (EMSP), and an analytical model is then proposed, with the aims of using that to study the influence of such EMSP when they are used to retrofit and upgrade reinforced concrete moment resisting frames (RC-MRF). Many RC-MRF are then designed in two cases: (1) in accordance with only Eurocode 2 and (2) in accordance with both Eurocode 2 and Eurocode 8. Capacities of such designed structures are evaluated by using nonlinear static analysis (Pushover) and nonlinear time history analysis under different types of soils and ground motions. The efficiency of using EMSP is evaluated in terms of strength, stiffness and energy dissipation. Additionally, with the presence of EMSP, some unfavorable behavior of RC-MRF under seismic action such as soft story mechanism can be prevented. [less ▲]

Detailed reference viewed: 56 (10 ULg)
Full Text
See detailEtude expérimentale de la résistance de panneaux de metal déployé soumis à des solicitations cycliques de cisaillement.
Phung Ngoc, Dung ULg; Degée, Hervé ULg; Plumier, André ULg

in Experimental Study of the Resistance of Expanded Metal Panels Submitted to Cyclic Shear Tests (2010)

Experimental and theoretical study of expanded metal panels (EMP) has shown that they are useful for seismically retrofitting reinforced concrete moment resisting frames (RC-MRF). Although this product ... [more ▼]

Experimental and theoretical study of expanded metal panels (EMP) has shown that they are useful for seismically retrofitting reinforced concrete moment resisting frames (RC-MRF). Although this product has merit of strength and ductility, it is at present only used for non-structural applications. There is no guidance existing to help the engineers determine the mechanical properties or to indicate in which field of the structures this product can be used. With the aims at providing quantitative data for these purposes and at introducing a simplified model of EMP working in shear, description and comparison of the results of 22 monotonic and cyclic experiments of 4 profiles of EMP in small and large scale is presented. Numerical approach with FINELG, a nonlinear finite element code developed at University of Liege, is used to calibrate and simulate the tests. A good correlation between tests and numerical simulations is observed. [less ▲]

Detailed reference viewed: 47 (10 ULg)
Full Text
Peer Reviewed
See detailTesting of Expanded Metal Sheets under Cyclic Shear Loadings
Phung Ngoc, Dung ULg; Degée, Hervé ULg; Plumier, André ULg

in 8th National Conference of Theoretical and Applied Mechanics NCTAM 2009 (2009)

Abstract: With the aims at determining the mechanical properties of Expanded Metal Sheet under seismic excitations, the research on Expanded Metal Sheet has been implementing at University of Liege ... [more ▼]

Abstract: With the aims at determining the mechanical properties of Expanded Metal Sheet under seismic excitations, the research on Expanded Metal Sheet has been implementing at University of Liege. Firstly, the square and rectangular sheets worked in monotonic shear loading was thoroughly studied by E.Pecquet[1]. In his study, there are three approaches used to determine the mechanic behavior of expanded metal sheets monotonically loaded in shear, that is, analytical models, numerical simulations and experimental investigations were performed and compared simultaneously. Secondly, the same dimensions of the sheets will be studied under cyclic shear loading. In this research, non-linear numerical stimulations and experimental investigation will be used to determine the properties of expanded metal sheets under cyclic shear loads. The analytical models will be proposed with the aims at modeling the sheets in Reinforced Concrete Frames, the next step of this study. Numerical stimulations are implemented with FINELG, a non linear finite element code. Expanded Metal Sheet Experiments under reverse loading are to be carried out at Laboratory of University of Liege. Experimental Investigations will be compared with numerical stimulations to propose an analytical model, hysteric loop for this type of material under cyclic loading. [less ▲]

Detailed reference viewed: 73 (4 ULg)
Full Text
See detailCHAPITRE 18. Exemple de calcul d’ossature en portique en béton armé
Phung Ngoc, Dung ULg

in CONSTRUCTION EN SEISMIQUE ZONE - Notes de cours - Prof. Plumier (2008)

An example of designing reinforced concrete moment resisting frames under seismic actions has been presented. The frames have been designed according to EC8.

Detailed reference viewed: 465 (4 ULg)