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Tu, Yongming
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Publications (10 of 17) Show all publications
Huang, Z., Tu, Y., Meng, S., Bagge, N., Nilimaa, J. & Blanksvärd, T. (2019). Validation of a numerical method for predicting shear deformation of reinforced concrete beams. Engineering structures, 197, Article ID 109367.
Open this publication in new window or tab >>Validation of a numerical method for predicting shear deformation of reinforced concrete beams
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2019 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 197, article id 109367Article in journal (Refereed) Published
Abstract [en]

The objective of this paper is to validate a 2D nonlinear finite element (FE) model for estimating the post-cracking shear deformation of reinforced concrete (RC) beams. The proposed FE model treated the cracked concrete as an orthotropic material in the framework of the fixed-crack approach. The experimental data for both the overall response (including the total and shear-induced deflection) and the detailed response (including the mean shear strain, mean vertical strain and principal compressive strain angle) of five I-section RC beams, monitored by the main authors of this paper with the Digital Image Correlation technique, were used to verify the proposed model. In addition, 27 further test beams evaluated in independent research programs were collected to assemble a database. The proposed FE model was further verified against the database. Two additional FE models (the rotating-crack model developed in this work and Response-2000 developed by Bentz (2000)) were also evaluated by simulating the detailed responses of the beams in the database. The results obtained validate the proposed FE model for predicting the post-cracking shear deformation of RC beams and indicate that the proposed FE model is more suitable for simulating the shear behaviour of RC beams than the rotating-crack model or Response-2000.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Reinforced concrete beams, Shear deformation, Nonlinear finite element model, Model verification, Digital image correlation
National Category
Engineering and Technology Other Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-75389 (URN)10.1016/j.engstruct.2019.109367 (DOI)
Note

Validerad;2019;Nivå 2;2019-08-14 (johcin)

Available from: 2019-08-05 Created: 2019-08-05 Last updated: 2019-08-14Bibliographically approved
Häggström, J., Blanksvärd, T., Collin, P. & Tu, Y. (2017). Full-scale testing to failure of a steel truss railway bridge. Proceedings of the Institution of Civil Engineers: Engineering Sustainability, 170(2), 93-101
Open this publication in new window or tab >>Full-scale testing to failure of a steel truss railway bridge
2017 (English)In: Proceedings of the Institution of Civil Engineers: Engineering Sustainability, ISSN 1478-4637, E-ISSN 1751-7664, Vol. 170, no 2, p. 93-101Article in journal (Refereed) Published
Abstract [en]

Significant resources have been invested in maintaining existing infrastructure. Many structures are becoming old, do not meet current requirements, or are reaching the end of their life cycle. It is not feasible or sustainable to replace all of those that may be deemed obsolete; however, often their specified capacities are very conservative. So there is an urgent need to obtain more robust knowledge of their true status. This paper describes a unique project, in which a 33 m long steel truss railway bridge (over the Åby River) was tested to failure. The findings can be used to identify optimal solutions for other bridges of the same design that are still in use, notably the bridge over Rautasjokk (a river in Sweden). These two bridges were tested in three stages. This paper focuses on the second stage, wherein Åby Bridge was subjected to static full-scale testing to failure, by pulling it downwards. The global failure mode consisted of buckling of the top chord with yielding of the steel starting at a total load of 8 MN and the peak load being reached at around 11 MN, corresponding to a load approximately four to five times higher than the characteristic design load.

Place, publisher, year, edition, pages
Institution of Civil Engineers, 2017
Keywords
bridges field testing & monitoring steel structures
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-62708 (URN)10.1680/jbren.15.00025 (DOI)000405988000002 ()
Note

Validerad;2017;Nivå 2;2017-06-07 (rokbeg)

Available from: 2017-03-27 Created: 2017-03-27 Last updated: 2018-12-14Bibliographically approved
Grip, N., Sabourova, N., Tu, Y. & Elfgren, L. (2017). Vibrationsanalys för tillståndsbedömning av byggkonstruktioner: Tillämpningsexempel : (Main results and summary in Swedish. Detailed results in English Appendices.). Stockholm
Open this publication in new window or tab >>Vibrationsanalys för tillståndsbedömning av byggkonstruktioner: Tillämpningsexempel : (Main results and summary in Swedish. Detailed results in English Appendices.)
2017 (Swedish)Report (Other academic)
Abstract [sv]

I projektet beskrivs och tillämpasnågra metoder för tillståndsbedömningav olika typer av konstruktioner med och utan skador.Tillståndsbedömningen skermed hjälp av vibrationsanalys.Detektering av skador av olika typ och storlekdiskuteras. Randvillkorens betydelse undersöks för att få överensstämmelse mellan förutspådda och uppmätta egenmoder och egenfrekvenser.Med den programvara som utvecklats är det möjligt att detektera sprickor i enkla betongplattor med hjälp av vibrationsmätningar. För mer avancerade konstruktioner finns en potential att vidareutveckla programvaran.Mätningar och analyser presenterasför femkonstruktioner: (1) En betongplatta –Sprickor har kunnat identifieras utifrån vibrationsmätningar och en successivt uppdaterad finit element modell (FEM).(2) En bågbro av betong över Långforsen i Kalix älv–Okända randvillkor har kunnat bestämmasför t ex undergrundens styvhetmedhjälp avuppmätta vibrationer. Detekteringav specifika skadorhar ännu inte kunnat genomföras.(3) En fackverksbro av stålöver Åby älv–Enviss skadedetektering har kunnat genomföras med vibrationsmätningar. Brons sårbarhet för korrosion och lokala mekaniska skador har studerats.(4) En förspänd betongbrotill gruvan i Kiruna–Modeller av bron har arbetats framför obelastatoch brottbelastat tillståndoch jämförts med uppmätta vibrationer med gott resultat.(5) Ett betonghus med nio våningar i Luleå –En FEM-modell av huseti bruksstadiethar tagits fram och resultat från den har jämförts med uppmätta vibrationer med gott resultat.Metoder och resultatpresenteras översiktligti rapportens huvudtext. Detaljerade beskrivningar gesi appendix.I appendix presenterasäven en programvaramed färdiga moduler för de undersökta konstruktionerna. Programmet kan laddas ner och användasfritt

Abstract [en]

In the project,methods are presented and appliedfor assessment ofdifferent types ofbuilding structures with and without damages.The assessmentis done withhelp ofvibration analysis.Detection of defects of different types and sizes are discussed. The influence of boundary conditions isstudied in order to get agreement between predicted and measured Eigen modes and Eigen frequencies.With the program that has been developed,is it now possible to detect cracks in simple concrete structures with help of measurements of vibrations. For more advanced structures there is a potentialto further develop the program. Measurements and analyses have been made for fivestructures:(1) A concrete slab–Cracks have been detected based on vibrationmeasurementsand a successivelyupdated Finite Element Model (FEM).(2) Aconcrete archbridge at Långforsen in Kalix River-Unknown boundary conditions havebeen possible todetermine with help of vibration measurementsregarding for example foundation properties. Detection of specific damages hasnot yet been possible.(3) A steel truss bridge over Åby River–Some detection of damages hasbeen possible to carry outwith Finite Element Model updatingregarding corrosion and mechanical damages.. (4) A prestressed concrete bridge to the mine in Kiruna-Several models of theundamaged and damagedbridgehave been established and they have been calibrated to measured vibration propertieswith good results.(5) A nine storey concrete building in Luleå–A FEM model has been developedfor the serviceability limit stateand results from it has been compared to measured vibrationswith good results.A general presentation is given ofthe developedmethods and resultsin the main text. Detailed descriptions are provided in Appendices.A program is presented with ready-to-use models for the studied structures. The program may be downloaded and is presented in detail in an Appendix.

Place, publisher, year, edition, pages
Stockholm: , 2017. p. 305
National Category
Infrastructure Engineering Building Technologies Computational Mathematics Mathematical Analysis
Research subject
Mathematics; Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-66140 (URN)
Projects
SBUF (Svenska Byggbranschens Utvecklingsfond)
Note

Dessutom har Zheng Huang, Chao Wang, Niklas Bagge, Jens Häggström, Jonny Nilimaa, Thomas Forsberg,Ola Enokson,Thomas Blanksvärd och Ulf Ohlsson bidragit med material och synpunkteroch som medförfattare i artiklar och konferensbidrag.

Available from: 2017-10-15 Created: 2017-10-15 Last updated: 2017-11-24Bibliographically approved
Qin, X.-C., Meng, S.-P., Cao, D.-F., Tu, Y.-M., Sabourova, N., Grip, N., . . . Elfgren, L. (2016). Evaluation of freeze-thaw damage on concrete material and prestressed concrete specimens. Construction and Building Materials, 125, 892-904
Open this publication in new window or tab >>Evaluation of freeze-thaw damage on concrete material and prestressed concrete specimens
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2016 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 125, p. 892-904Article in journal (Refereed) Published
Abstract [en]

The pore structure of the hardened concrete and the microscopic changes of a few selected pores throughout the freeze-thaw test were investigated by a method combining RapidAir and digital metalloscope. Traditional tests were also performed to evaluate the macroscopic change caused by freeze-thaw cycles (FTCs). The investigation shows that the concrete material, of which the spacing factor is 0.405 mm and the air content is 2.38%, can still withstand more than 300 FTCs. Severe microscopic damages occurred after approximately 200 FTCs and the freeze-thaw damage were gradually aggravated afterwards. Prestress forces have a remarkable impact on the failure pattern under FTCs. It was further found that the compressive strength as an indicator is more reliable than the relative dynamic modulus of elasticity in evaluating the freeze-thaw damage on concrete material. In addition, the test and analysis show that the measured prestress losses of bonded specimen are larger than that of unbounded specimen under the attack of FTCs due to the duct grouting effect. The ultimate freeze-thaw prestress loss is about 5% of σconσcon for both the bonded and unbonded specimens because the grouting cement paste will eventually be completely destroyed.

Place, publisher, year, edition, pages
Elsevier, 2016
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-59653 (URN)10.1016/j.conbuildmat.2016.08.098 (DOI)000385600100088 ()2-s2.0-84984828018 (Scopus ID)
Note

Validerad; 2016; Nivå 2; 2016-10-10 (andbra)

Available from: 2016-10-11 Created: 2016-10-11 Last updated: 2019-02-22Bibliographically approved
Wang, C., Wang, Z., Zhang, J., Tu, Y.-M., Grip, N., Ohlsson, U. & Elfgren, L. (2016). FEM based research on the dynamic response of a concrete railway arch bridge. In: Elfgren, Lennart; Jonsson, Johan; Karlsson, Mats; Rydberg-Forssbeck, Lahja; Sigfid, Britt2016 (Ed.), IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment. Paper presented at 19th IABSE Congress Stockholm, 21-23 September 2016 (pp. 2472-2479). CH - 8093 Zürich, Switzerland
Open this publication in new window or tab >>FEM based research on the dynamic response of a concrete railway arch bridge
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2016 (English)In: IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment / [ed] Elfgren, Lennart; Jonsson, Johan; Karlsson, Mats; Rydberg-Forssbeck, Lahja; Sigfid, Britt2016, CH - 8093 Zürich, Switzerland, 2016, p. 2472-2479Conference paper, Published paper (Refereed)
Abstract [en]

The dynamic response of a concrete railway arch bridge is studied through a case study of the bridge over Kalix River, situated at Långforsen on the railway line between Kalix and Morjärv in northern Sweden. A simplified beam-element model, a spatial grillage-beam model and a refined shell-element model were built to analyze the bridge structure. A methodology was applied where measured static and dynamic responses were used to update finite element models of Långforsen Bridge. A multi-response objective function was presented, and the finite element method was proved feasible by comparison of predicted and measured response. In the paper comparative analyses were made of the time history displacement of three finite element models under three measured load cases. A standard train model from EUROCODE, HSLM-A 1, was applied and the dynamic responses under different speeds were studied. The results showed that a refined shell element model could accurately analyze dynamic responses of the concrete railway arch bridge in a better way than beam element and spatial grillage models. The dynamic analysis based on this type of shell model can give an optimized suggestion for the railway operation as well as for the design of high-speed railway bridges.

Place, publisher, year, edition, pages
CH - 8093 Zürich, Switzerland: , 2016
Series
IABSE Congress Reports
Keywords
Refined shell element model, Dynamic response, Moving load, Concrete railway arch bridge
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-62172 (URN)2-s2.0-85018948830 (Scopus ID)978-3-85748-144-4 (ISBN)
Conference
19th IABSE Congress Stockholm, 21-23 September 2016
Funder
Swedish Transport Administration
Note

Financial support from the National Natural Science Foundation of China (Project No 51378104) and

"A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, PAPD”, Southeast University (SEU).

Available from: 2017-02-25 Created: 2017-02-25 Last updated: 2019-09-11Bibliographically approved
Huang, Z., Grip, N., Sabourova, N., Bagge, N., Tu, Y.-M. & Elfgren, L. (2016). Modelling of Damage and its Use in Assessment of a Prestressed Bridge. Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Modelling of Damage and its Use in Assessment of a Prestressed Bridge
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2016 (English)Report (Other academic)
Abstract [en]

A 55 years old and 121.5 m long ve-span prestressed bridge has been subjected toshear failure test in Kiruna, Sweden. This in-situ test is a desirable test to validate andcalibrate the existing nonlinear nite element program for predicting the shear behaviorof reinforced and prestressed concrete structures.Two 3D nite element (FE) models of the Kiruna Bridge are built in commercial soft-ware Abaqus, one using shell-elements and one using a combination of shell and beam ele-ments. Predictions obtained from these two models are well consistent with mode shapesand eigenfrequencies computed from acceleration measurements on the bridge before andafter loading it to failure. Shear-failure test of this bridge performed by Lulea Universityof Technology (LTU) is also simulated using the built-in concrete damage plasticity (CDP)model in Abaqus. The predicted load-displacement curve is in good agreement with themeasurement. Verication of the CDP model is conducted at element and member levelwith two dierent damage parameter evolutions. According to the verication, it indi-cates the damage parameter will aect the predicted shear behavior of reinforced concretestructures and it is not reliable to adopt the CDP model to simulate the shear behaviorof reinforced concrete structures based on the present research.A long term goal is to use use the measured mode shapes, eigenfrequencies and FEmodels for evaluating methods for damage identication. Such methods are important formaintenance of dierent structures, for extending their life span and for better knowledgeof their load carrying capacity. We describe how so-called sparse regularization niteelement method updating (FEMU) methods can be used. We then demonstrate someimportant properties of such methods with simulations on a Kirchho plate. For instance,the simulations suggest that both eigenfrequencies and mode shapes should be used forprecise localization of the damage.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2016. p. 21
Series
Research report / Luleå University of Technology, ISSN 1402-1528
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-61185 (URN)978-91-7583-820-5 (ISBN)
Available from: 2016-12-21 Created: 2016-12-21 Last updated: 2018-05-22Bibliographically approved
Huang, Z., Tu, Y.-M., Grip, N., Sabourova, N., Bagge, N., Blanksvärd, T., . . . Elfgren, L. (2016). Modelling of Damage and its use in Assessment of a PrestressedConcrete Bridge. In: Lennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid (Ed.), IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovativeand Sustainable Built Environment. Paper presented at 19th IABSE Congress, Stockholm 2016, September 21-23 (pp. 2093-2108). CH - 8093 Zürich, Switzerland
Open this publication in new window or tab >>Modelling of Damage and its use in Assessment of a PrestressedConcrete Bridge
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2016 (English)In: IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovativeand Sustainable Built Environment / [ed] Lennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid, CH - 8093 Zürich, Switzerland, 2016, p. 2093-2108Conference paper, Published paper (Refereed)
Abstract [en]

A five-span prestressed concrete bridge has been subjected to a loading test up to failure in Kiruna, Sweden. The bridge was 55 years old and had a length of 121.5 m. The test has been used to validate and calibrate existing nonlinear finite element programs for predicting the shear behavior of reinforced and prestressed concrete structures. Two 3D finite element (FE) models of the Kiruna Bridge are built in commercial software Abaqus, one using shell-elements and one using a combination of shell and beam elements. Predictions obtained from these two models are well consistent with mode shapes and eigenfrequencies computed from acceleration measurements on the bridge before and after loading it to failure.The shear failure of the bridge is also simulated using the built-in concrete damage plasticity (CDP)model in Abaqus. The predicted load-displacement curve is in good agreement with the measurements. Verification of the CDP model is conducted at element and member level with two different damage parameter evolutions. The verification indicates that the damage parameter will affect the predicted shear behavior. It does not seem to be reliable to adopt the CDP model to simulate the shear behavior in the present research. A long term goal is to use use the measured mode shapes, eigenfrequencies and FE models for evaluating methods for damage identification. Such methods are important for maintenance of different structures, for extending their life span and for better knowledge of their load carrying capacity. The use is described of so-called sparse regularized finite element method updating (FEMU) methods. Some important properties of such methods are demonstrated using simulations on a Kirchhoff plate. For instance, the simulations suggest that both eigenfrequencies and mode shapes should be used for precise localization of the damage.

Place, publisher, year, edition, pages
CH - 8093 Zürich, Switzerland: , 2016
Series
IABSE Congress Reports
Keywords
Concrete damage plasticity model, refined shell element model, shear failure test, shear behavior, five-span prestressed concrete bridge, FEM updating, sparse regularization, Kirchhoff plate.
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-60996 (URN)2-s2.0-85018991487 (Scopus ID)978-3-85748-144-4 (ISBN)
Conference
19th IABSE Congress, Stockholm 2016, September 21-23
Available from: 2016-12-10 Created: 2016-12-10 Last updated: 2018-03-27Bibliographically approved
Cai, J., Deng, X., Ya, Z., Feng, J. & Tu, Y. (2015). Bistable behavior of the cylindrical origami structure with Kresling pattern (ed.). Paper presented at . Journal of mechanical design (1990), 137(6), Article ID 61406.
Open this publication in new window or tab >>Bistable behavior of the cylindrical origami structure with Kresling pattern
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2015 (English)In: Journal of mechanical design (1990), ISSN 1050-0472, E-ISSN 1528-9001, Vol. 137, no 6, article id 61406Article in journal (Refereed) Published
Abstract [en]

The deployment of a cylinder based on origami with Kresling pattern, whose basic mechanisms are formed by the buckling of a thin cylindrical shell under torsional loading, is studied in this paper. The model consists of identical triangular panels with cyclic symmetry and has a small displacement internal inextensional mechanism. First, geometric formulation of the design problem is presented. Then, assuming that the deployment and folding process is uniform, the bistable behavior of the cylinder is discussed. It can be found that, during the deployment, the dimensionless strain energy increases first and then reduces to zero but followed by another sharp increase. Moreover, the limit condition of geometry parameters for the bistable phenomenon is also discussed. Finally, the bistable behavior is also studied by using numerical simulations for simple and more complex case of the cylinder with multistory. The numerical results agree well with the analytical predictions. Therefore, comparisons with finite element predictions have shown that the analytical solutions given in this paper are accurate and have validated the assumptions made in the derivations

National Category
Construction Management
Research subject
Construction Engineering and Management
Identifiers
urn:nbn:se:ltu:diva-5149 (URN)10.1115/1.4030158 (DOI)000353918100006 ()2-s2.0-84929162558 (Scopus ID)32dc86ef-4e0d-41d2-8851-b767c651c7e9 (Local ID)32dc86ef-4e0d-41d2-8851-b767c651c7e9 (Archive number)32dc86ef-4e0d-41d2-8851-b767c651c7e9 (OAI)
Note
Validerad; 2015; Nivå 2; 20150525 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Nilimaa, J., Häggström, J., Blanksvärd, T., Täljsten, B., Elfgren, L., Tu, Y., . . . Paulsson, B. (2015). Extend the life of existing railway bridges: Results from EU FP7 project MAINLINE (ed.). In: (Ed.), (Ed.), IABSE Conference Geneva 2015: Structural Engineering: Providing Solutions to Global Challenges. Paper presented at IABSE Conference : Structural Engineering: Providing Solutions to Global Challenges 23/09/2015 - 25/09/2015 (pp. 1219-1226). Geneva: International Association for Bridge and Structural Engineering
Open this publication in new window or tab >>Extend the life of existing railway bridges: Results from EU FP7 project MAINLINE
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2015 (English)In: IABSE Conference Geneva 2015: Structural Engineering: Providing Solutions to Global Challenges, Geneva: International Association for Bridge and Structural Engineering, 2015, p. 1219-1226Conference paper, Published paper (Other academic)
Abstract [en]

There is a need to extend the life and capacity of many existing bridges. One of the objects of the EU FP7 Project MAINLINE, 2011-2014, was to facilitate this. Guidelines for assessment and strengthening methods are presented as well as case studies in which existing bridges are studied in order to extend their life length. One example is the prestressing of the slab in a one-span concrete trough bridge in order to increase its load-carrying capacity. Horizontal holes were drilled trough the slab and in them steel bars were placed and post-tensioned. In this way a compressive stress was introduced into the concrete section so that it’s bending and shear capacity was increased.In another study a metal truss bridge was monitored in order to check strain and stress ranges in critical connections to enable an enhanced evaluation of the remaining fatigue resistance. The studied bridge was then replaced and loaded to failure to study its robustness and the reliability of applied assessment methods. The results could then be applied to prolong the life of an identical twin bridge located in the northern part of Sweden. A Life Cycle Assessment Tool (LCAT) has been developed to enable Infrastructure Managers to choose optimal maintenance strategies.

Place, publisher, year, edition, pages
Geneva: International Association for Bridge and Structural Engineering, 2015
National Category
Infrastructure Engineering
Research subject
Structural Engineering; Attractive built environment (AERI)
Identifiers
urn:nbn:se:ltu:diva-31658 (URN)84971229053 (Scopus ID)5e814bc4-21a1-4935-99b6-6d8bde81836a (Local ID)9783857481406 (ISBN)5e814bc4-21a1-4935-99b6-6d8bde81836a (Archive number)5e814bc4-21a1-4935-99b6-6d8bde81836a (OAI)
Conference
IABSE Conference : Structural Engineering: Providing Solutions to Global Challenges 23/09/2015 - 25/09/2015
Projects
Mainline-MAINtenance, renewaL and Improvement of rail transport iNfrastructure to reduce Economic and environmental impacts
Note
Godkänd; 2015; 20150923 (andbra)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-03-26Bibliographically approved
Ge, W., Zhang, J., Cao, D. & Tu, Y. (2015). Flexural behaviors of hybrid concrete beams reinforced with BFRP bars and steel bars (ed.). Paper presented at . Construction and Building Materials, 87, 28-37
Open this publication in new window or tab >>Flexural behaviors of hybrid concrete beams reinforced with BFRP bars and steel bars
2015 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 87, p. 28-37Article in journal (Refereed) Published
Abstract [en]

Flexural behaviors of hybrid concrete beams reinforced with BFRP (Basalt Fiber Reinforced Plastic) bars and steel bars are studied in this paper. Tensile test, standard pull-out test of BFRP bars, and static flexural experiment of five different hybrid reinforced concrete beams were made. The tests show that BFRP bars have high tensile strength and low elastic modulus compared with steel bars. The bond strength between BFRP bars and concrete is similar to the bond strength of steel bars and concrete and shows good bond performance. The bond strength relative coefficient of BFRP bars can be considered to be 1.0. The crack spacing and crack width are analyzed and suitable formulas for calculation are proposed. The flexural capacity of appropriate hybrid reinforced beams is analyzed and a simplified formula for calculating its value is proposed. Results show that the value of the flexural capacity calculated by the proposed simplified formula is close to the experimental value. This proves that the formula can be successfully applied. By controlling the reinforcement ratio and the value of Af/As appropriately, the ductility of hybrid reinforced beams can meet the requirements of normal service conditions.

National Category
Construction Management
Research subject
Construction Engineering and Management
Identifiers
urn:nbn:se:ltu:diva-3099 (URN)10.1016/j.conbuildmat.2015.03.113 (DOI)000355032500004 ()2-s2.0-84927591876 (Scopus ID)0e20df16-5a22-4c04-a135-7fdb94d7e101 (Local ID)0e20df16-5a22-4c04-a135-7fdb94d7e101 (Archive number)0e20df16-5a22-4c04-a135-7fdb94d7e101 (OAI)
Note
Validerad; 2015; Nivå 2; 20150414 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
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