2015
3
2
6
88
Comparison between Alternative Load Path Method and a Direct Applying Blast Loading Method in Assessment of the Progressive Collapse
2
2
Extensive research has been focused on the progressive collapse analysis of buildings and most of them are based on the alternative path method (APM) with sudden removal of one or several columns. However, in this method the damage of adjacent elements of removed columns under blast conditions was ignored and this issue can lead to an incorrect prediction of progressive collapse. Therefore, in this study to evaluate the alternative load path method in predicting the progressive collapse due to blast loading, a 3D finite element model of a 7 storey steel building simulated and the behavior of structure was studied using the direct applying of blast load method and alternative load path method. For simulating and applying the blast loading and assessment of their direct effects on structures, a blast load equivalent to 1 ton TNT was considered at a distance of 4 meters from the corner of the structure. The pressures of this blast in 4 loading cases are applied to the adjacent structural members and the structural response has been examined. Finally, the exciting forces in adjacent structural members of blast site in each case have been compared. The results show that in assessment of the potential of progressive collapse occurrence by considering the blast loading as the initial reason of failure, the structure response will be different compared with the alternate load method that in which the initial reason of progressive collapse was ignored.
1

1
15


Meysam
Bagheripourasil
M.Sc., Department of Civil Engineering, University of Mohaghegh Ardabili, Ardabil, Iran
Iran
meysam_bagheri_p@yahoo.com


Yaghoub
Mohammadi
Assistant Professor, Department of Civil Engineering, University of Mohaghegh Ardabili, Ardabil, Iran
Iran
yaghoubm@uma.ac.ir
Progressive collapse
Blast loading
steel moment frame
finite element method
[[l] EN 199117 (2006). Eurocode 1: “Actions on structures Part 17: General actions accidental actions”. European Committee for Standardization.##[2] Unified Facilities Criteria (UFC)DoD. (2005). “Design of buildings to resist progressive collapse”. Department of Defense.##[3] General Services Administration (GSA). (2003). “Progressive collapse analysis and design guidelines for new federal office buildings and major modernization projects”. Washington (DC) Office of Chief Architect.##[4] Feng Fu. (2013). “Dynamic response and robustness of tall buildings under blast loading”. Journal of Constructional Steel Research 80, pp. 299–307.##[5] Marjanishvili, SM. “Progressive analysis procedure for progressive collapse”. (2004). J Perform Constr Facilities ASCE ;18(2):79–85.##[6] Izzuddin BA, Vlassis AG, Elghazouli AY. Nethercot DA. (2008). “Progressive collapse of multistorey buildings due to sudden column”. loss–Part I: Simplified assessment framework. Eng. Struct.;30:1308–18.##[7] Hartmann D, Breidt M, Nguyen V, Stangenberg F, Hohler S, Schweizerhof K, et al. (2008). “Structural collapse simulation under consideration of uncertainty Fundamental concept and results”. ComputStruct;86:2064–78.##[8] Moller, B., Liebscher M., Schweizerhof, K., Mattern, S., Blankenhorn, G. (2008). “Structural collapse simulation under consideration of uncertainty Improvement of numerical efficiency”.Comput.Struct. ;86:1875–84.##[9] Song, B., Giriunas, K., Sezen, H. “Progressive collapse testing and analysis of a steel frame building”. (2014). J Constr Steel Res;94:76–83. http://dx.doi.org/10.1016/j. jcsr.2014.11.002.##[10] Hosseini, M., Fanaie, N., Yousefi, AM. (2014). “Studying the vulnerability of steel moment resistant frames subjected to progressive collapse”. Indian J Sci Technol 2014;7(3): 335–42.Eng. Struct.;30:1308–18.##[11] Yousefi, AM., Hosseini, M., Fanaie, N., (2014). “Vulnerability assessment of progressive collapse of steel moment resistant frames”. Trends Appl Sci Res 2014;9(8):450–60.##[12] SAP 2000. “Advanced structural analysis program”. (2009). Version 12.Berkeley, CA, USA: Computers and Structures, Inc. (CSI).##[13] Tenth Issue of Iranian National Building Code, Planning and Construction of Steel, Ministry of Housing and Urban Development, Department of Housing and Construction Office. Developing and Promoting the National Building Regulations, 2013 (In Persian).##[14] Iranian National Building Code  6th Chapter, Building Loads, Ministry of Housing and Urban Development, Department of Housing and Construction Office, Developing and Promoting National Regulations, 2013. (In Persian).##[15] ABAQUS theory manual. (2003). Version 6.7 Pawtucket, R.I: Hibbitt, Karlsson and Sorensen, Inc.##[16] Richard, L., Hong, C. (2004). “Explosion and Fire Analysis of steel Frames Using Fiber Element Approach”. ASCE Journal of Structural Engineering, 9911000.##[17] Song, B., Sezen, H., Giriunas, K., (2010). “Experimental and analytical assessment on progressive collapse potential of actual steel frame buildings”. In: ASCE structures conference and North American steel construction conference, Orlando, Florida; May 12–15.##[18] Bagheripourasil, M. (2013). “Evaluation of progressive collapse due to blast loading in steel moment frames”. Master’s thesis. University of Mohaghegh Ardabili.##[19] G, Le., Blanc, M., Adoum, V., Lapoujade. (2005). “External blast load on structuresEmpirical Approach”, 5th European LSDYNA Users conference.##[20] ATBLAST 2.0. (2000). Applied Research Associates.##[21] Yandzio, E., Gough, M. (1999). “Protection of buildings against explosions”. Sci Publication, 244.##[22] Shi, Y., Li, Z., Hao, H. (2010). “A new method for progressive collapse analysis of RC frames under blast loading”. Engineering Structures.pp.16911703.##[23] US Departments of the Army, Navy and Airforce. Technical Manual, Army TM51300, Navy NAVFAC P397, Air Force AFR 88–22, “Structures to resist the effects of accidental explosions”. Washington, DC: US Department of Commerce, National Technical Information Service; 1990.##[24] Hopkinson, B. (1915). British Ordnance board minutes 13565.##[25] Cranz, C. (1926). Lehrbuch der Ballistik. Berlin: Springer.##[26] Larcher, M. (2008). “ PressureTime Functions for the Description of Air Blast Waves”. JRC Thechnical notes.##]
Serviceability Response of Rehabilitated Unbonded Posttensioned Indeterminate IBeams Consisting UHSSCC
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2
The ultrahigh strength selfcompacting concrete, UHSSCC is the new generation type of concrete with a compressive strength higher than 80MPa. The application of this type of concrete on the serviceability state in CFRP strengthened unbonded posttensioned indeterminate Ibeam is monitored and the results are compared theoretically using different standards. For this aim, full scale Ibeam of 9m length was cast, by UHSSCC. During the beam service load test, the stress and strain of materials, and also deflection and crack widths were monitored at different locations using different types of sensors. Based on the experimental measurements and observations, the beam serviceability response was compared theoretically by different methods. As the considerations prepared in the standards do not cover strengthening of such members with unbonded tendons, and also no trace of deflection prediction for such continuous member, one can find in the open literature. It is therefore, this investigation was planned. A comparison between theoretical and monitored results was performed for serviceability response and it was found that although, the stress of materials are well within the standards limitations for crack widths of 0.1 and 0.2 mm of bonded tendon, but the full service load is reached at a higher load, while the flexural crack, experience a width of 0.3 mm. It is also apparent that the loads corresponding to the conventional suggested deflection limits will cause to exceed serviceability state of strengthened unbonded beam, and new limitations are introduced for crack widths of 0.1, 0.2 and 0.3 mm to predict service deflection of beams.
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29


Mohammad
Maghsoudi
Ph.D. Student, Civil Eng. Dept., Shahid Bahonar University of Kerman, Kerman, Iran
Iran
maghsoudi_mohammad@yahoo.com


Ali Akbar
Maghsoudi
Professor, Civil Eng. Dept., Shahid Bahonar University of Kerman, Kerman, Iran
Iran
maghsoudi.a.a@uk.ac.ir
Serviceability
Unbonded posttensioned
Continuous beams
UHSSCC
Monitored
[[1] CEBFIP Model Code for structures. (1990). “ComiteEuro international du beton/federation internationale de la precomtrainte”.##[2] ACI 209R. (1992). “Prediction of creep, shrinkage and temperature effects in concrete structures”. American Concrete Institute, Farmington Hills, MI, USA.##[3] Rashid, M. A., Mansur, M. A., Paramasivam, P. (2002). “Correlations between Mechanical Properties of HighStrength Concrete”. Journal of Materials in Civil Engineering, Vol. 14, pp. 230238.##[4] Ghasemi, S., Maghsoudi. A.A., Akbarzadeh.B., H., Ronagh, H.R. (2015). “Sagging and hogging strengthening of continuous unbonded posttensioned HSC beams by NSM and EBR”. Journal of Composite and Construction (ASCE), Vol. 20, pp. 04015056113.##[5] Toutanji, H., Zhao, L., Zhang, Y. (2006). “Flexural behavior of reinforced concrete beams externally strengthened with CFRP sheets bonded with an inorganic matrix”. Engineering Structures, Vol. 28, pp. 557566.##[6] Xiong, G.J., Jiang, X., Liu, J.W., Chen, L. (2007). “A way for preventing tension delamination of concrete cover in midspan of FRP strengthened beams”. Construction and Building Materials, Vol. 21, pp. 402–408.##[7] Hashemi, H. (2007). “Study of reinforced high strength concrete strengthened beams by FRP”. PhD. Thesis, Civil Eng. Dept., Shahid Bahonar University of Kerman, Kerman, Iran.##[8] Askari. D.Y., Maghsoudi, A.A. (2014). “Monitoring and theoretical losses of posttensioned indeterminate Ibeams”. Magazine of Concrete Research, Vol. 66, pp. 116.##[9] Askari. D.Y., Maghsoudi, A.A., (2014). “Ultimate tendon stress in CFRP strengthened unbonded HSC posttensioned continuous Ibeams”. Journal of Rehabilitation in Civil Engineering, Vol. 2, pp. 3545.##[10] Maghsoudi, A.A., Askari. D.Y. (2015). “Ultimate unbonded tendon stress in CFRP strengthened posttensioned indeterminate Ibeams cast with HSCs”. International Journal of Engineering, Transactions C, Vol. 28, pp. 350359.##[11] PCI. (2003). “Interim guidelines for the use of selfconsolidating concrete in precast/prestressed concrete institute member plants”. Chicago, IL, USA.##[12] ACI318R. (2011). “Building code requirements for structural concrete and commentary”. American Concrete Institute, Farmington Hills, MI, USA.##[13] Vu., N.A., Castel., A., François., R. (2010). “Response of posttensioned concrete beams with unbonded tendons including serviceability and ultimate state”. Engineering Structures, Vol. 32, pp. 556569.##[14] Fib. (2001). “Externally bonded FRP reinforcement for RC structures”. Technical Report Bulletin 14, Geneva, Switzerland. ##[15] ACI 318R14. (2014). “Building code requirements for structural concrete and commentary”. American Concrete Institute, Farmington Hills, MI, USA.##[16] ACI 440.2R. (2008). “Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures”. American Concrete Institute, Detroit, MI, USA.##[17] ACI 363R. (2010). “Stateoftheart report on highstrength concrete”. American Concrete Institute, Farmington Hills, MI, USA.##[18] Fib. (2008). “Constitutive modelling of high strength high performance concrete”. Technical Report Bulletin 42, Geneva, Switzerland.##[19] Akbarzadeh B.H., Maghsoudi, A.A. (2009). “Experimental investigations and verification of debonding strain of RHSC continuous beams strengthened in flexure with externally bonded FRPs”. Journal of Materials and Structures, Vol. 43 pp. 815837.##[20] Pellegrino, C., Modena, C. (2009). “Flexural strengthening of realscale RC and PRC beams with endanchored pretensioned FRP laminates”. ACI Structural journal, Vol. 106 pp. 319328.##[21] BS 8110. (1997). “Structural use of concrete”. Part 1, British Standards Institution, London, UK.##]
Strengthening of Existing RC TwoWay Slabs using New Combined FRP fabric/rod Technique
2
2
This study presents the results of an experimental program to investigate the effectiveness of an innovative combined FRP technique using combination of externally bonded (EB) FRP fabrics and near surface mounted (NSM) FRP rods for flexural strengthening of existing reinforced concrete (RC) twowayslabs with low clear cover thickness. Three fullscale RC slabs (1500×1500×120 mm) were tested under monotonic fourpoint bending. One slab was kept unstrengthened as the control specimen, one slab was strengthened using NSM GFRP rods, and the other one slab was strengthened using combination of EB CFRP fabrics and NSM GFRP rods. The loaddeflection responses, strain measurements, and failure modes of the tested slabs were studied and discussed. The behavior of the slab strengthened with this technique was compared to the behavior of the slab strengthened with GFRP rods. The test results confirmed the feasibility and efficacy of this technique in improving the flexural behavior of RC twoway slabs. Strengthened slabs showed an increase in flexural capacity between 250 and 394% over the control specimen. The slab strengthened using this technique showed higher ductility compared to the slab strengthened using GFRP rods. A 3D nonlinear numerical model was also developed using the finite element (FE) method to predict the flexural behavior of the tested slabs. A good agreement between experimental and numerical results was observed.
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30
44


Pejman
Behzard
Ph.D. In Structural Engineering, Faculty of Civil Engineering, Semnan University, Semnan, Iran
Iran
pejmanb@gmail.com


Mohammad Kazem
Sharbatdar
Associate Professor, Faculty of Civil Engineering, Semnan University, Semnan, Iran
Iran
m_sharbatdar@hotmail.com


Ali
Kheyroddin
Professor, Faculty of Civil Engineering, Semnan University, Semnan, Iran
Iran
kheyroddin@semnan.ac.ir
Combined FRP technique
NSM GFRP rods
EB CFRP fabrics
RC twoway slabs
Finite element
[[1] ACI (American Concrete Institute). (2008). ACI 440.2R08: "Guide for the design and construction of externally bonded FRP system for strengthening concrete structures". American Concrete Institute, Farmington Hills, MI, USA.##[2] Badawi, M., Soudki, K. (2009). "Flexural strengthening of RC beams with prestressed NSM CFRP rods–experimental and analytical investigation". Constr Build Mater, 23(10), pp.32923300.##[3] Anwarul Islam, AKM. (2009). "Effective methods of using CFRP bars in shear strengthening of concrete girders". Eng Struct J, 31, pp.709–714.##[4] De Lorenzis, L., Teng, JG. (2007). "Nearsurface mounted FRP reinforcement: An emerging technique for strengthening structure". J Compos Part B Eng, 38(2), pp.119–143.##[5] ElHacha, R., Riskalla, SH. (2004). "Nearsurfacemounted fiberreinforced polymer reinforcements for flexural strengthening of concrete structures". ACI Struct J, 101(5), pp.717–726.##[6] Barros, JAO., Dias, SJE., Lima, JLT. (2007). "Efficacy of CFRPbased techniques for the flexural and shear strengthening of concrete beams". J Cem Concr Compos, 29(3), pp.203–217.##[7] Ceroni, F. (2010). "Experimental performances of RC beams strengthened with FRP materials". Constr Build Mater, 24(9) , pp.15471559.##[8] Jalali, M., Sharbatdar, MK., Chen, JF., Jandaghi Alaee, F. (2012). "Shear strengthening of RC beams using innovative manually made NSM FRP bars". Constr Build Mater, 36, pp.990–1000.##[9] Barros, JAO., Baghi, H., Dias, SJE., Gouveia, AV. (2013). "A FEMbased model to predict the behaviour of RC beams shear strengthened according to the NSM technique". Eng Struct J, 56, pp.1192–1206.##[10] Sharaky, IA., Torres, L., Comas, J., Barris, C. (2014). "Flexural response of reinforced concrete (RC) beams strengthened with near surface mounted (NSM) fibre reinforced polymer (FRP) bars". Compos Struct J, 109, pp.8–22.##[11] Bonaldo, E., Barros, JAO., Lourenco, PB. (2008). "Efficient strengthening technique to increase the flexural resistance of existing RC slabs". J Compos Constr, 12(2), pp.149–159.##[12] Elgabbas, F., ElGhandour, AA., Abdelrahman, AA., ElDieb, AS. (2010). "Different CFRP strengthening techniques for prestressed hollow core concrete slabs: Experimental study and analytical investigation". Compos Struct J, 92, pp.401–411.##[13] Dalfré, GM., Barros, JAO. (2013). "NSM technique to increase the load carrying capacity of continuous RC slabs". Eng Struct J, 56, pp.137–153.##[14] Mostakhdemin Hosseini, MR., Dias, SJE., Barros, JAO. (2014). "Effectiveness of prestressed NSM CFRP laminates for the flexural strengthening of RC slabs". Compos Struct J, 111, pp.249–258.##[15] Breveglieri, M., Barros, JAO., Dalfré, GM., Aprile, A. (2012). "A parametric study on the effectiveness of the NSM technique for the flexural strengthening of continuous RC slabs". Compos Part B Eng, 43(4), pp.1970–1987.##[16] Foret, G., Limam, O. (2008). "Experimental and numerical analysis of RC twoway slabs strengthened with NSM CFRP rods". Constr Build Mater, 22(10), pp.2025–2030.##[17] ANSYS – release version 11. (2007). "A finite element computer software theory and user manual for nonlinear structural analysis". ANSYS 2007, Inc. Canonsburg, PA.##[18] ACI (American Concrete Institute). (1999). ACI 31899: "Building code requirements for structural concrete, American Concrete Institute". Farmington Hills, MI, USA.##[19] William, KJ., Warnke, EP. (1975). "Constitutive model for the triaxial behavior of concrete". IABSE Proc., Int. association for bridge and structural engineering, Zürich, 19, pp.174.##]
A New TwoStage Method for Damage Identification in LinearShaped Structures Via Grey System Theory and Optimization Algorithm
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2
The main objective of this paper is concentrated on presenting a new twostage method for damage localization and quantification in the linearshaped structures. A linearshaped structure is defined as a structure in which all elements are arranged only on a straight line. At the first stage, by employing Grey System Theory (GST) and diagonal members of the Generalized Flexibility Matrix (GFM), a new damage index is suggested for damage localization using only the first several modes’ data. It is followed by the second stage which is devoted to damage quantification in the damaged elements by proposing an optimizationbased procedure to formulate fault prognosis problem as an inverse problem, and it is solved by the Pattern Search Algorithm (PSA) to reach the optimal solution. The applicability of the presented method is demonstrated by studying different damage patterns on three numerical examples of linearshaped structures. In addition, the stability of the presented method in the presence of random noises is evaluated. The obtained results reveal good and acceptable performance of the proposed method for detecting damage in linearshaped structures.
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58


Gholamreza
Ghodrati Amiri
Center of Excellence for Fundamental Studies in Structural Engineering, School of Civil Engineering, Iran University of Science & Technology, Tehran, Iran
Iran
ghodrati@iust.ac.ir


Ali
Zare Hosseinzadeh
Center of Excellence for Fundamental Studies in Structural Engineering, School of Civil Engineering, Iran University of Science & Technology, Tehran, Iran
Iran
a.hh.hoseinzade@gmail.com


Mojtaba
Jafarian Abyaneh
Center of Excellence for Fundamental Studies in Structural Engineering, School of Civil Engineering, Iran University of Science & Technology, Tehran, Iran
Iran
mojtabajafarian13@gmail.com
Damage identification
Modal data
Generalized flexibility matrix
Grey system theory
Pattern search algorithm
[[1] Fan, W., Qiao, P. (2011). “Vibrationbased damage identification methods: a review and comparative study”. Structural Health Monitoring, Vol. 10, No. 1, pp. 83111.##[2] Kim, J.T., Stubbs, N. (2003). “Crack detection in beamtype structures using frequency data”. Journal of Sound and Vibration, Vol. 259, No. 1, pp. 145160.##[3] Xia, Y., Hao, H. (2003). “Statistical damage identification of structures with frequency changes”. Journal of Sound and Vibration, Vol. 263, No. 4, pp. 853870.##[4] Rucka, M., Wilde, K. (2006). “Application of continuous wavelet transform in vibration based damage detection method for beams and plates”. Journal of Sound and Vibration, Vol. 297, No. (35), pp. 536550.##[5] Poudel, U.P., Fu, G.K., Ye, H. (2007). “Wavelet transformation of mode shape difference function for structural damage location identification”. Earthquake Engineering & Structural Dynamics, Vol. 36, No. 8, pp. 10891107.##[6] Bagheri, A., Ghodrati Amiri, G., Seyed Razzaghi, S.A. (2009). “Vibrationbased damage identification of plate structures via curvelet transform”. Journal of Sound and Vibration, Vol. 327, No. (35), pp. 593–603.##[7] Homaei, F., Shojaee, S., Ghodrati Amiri, G. (2014). “A direct damage detection method using multiple damage localization index based on mode shapes criterion”. Structural Engineering and Mechanics, Vol. 49, No. 2, pp. 183202.##[8] Ghodrati Amiri, G., Jalalinia, M., Zare Hosseinzadeh, A., Nasrollahi, A. (2015). “Multiple crack identification in Euler beams by means of Bspline wavelet”. Archive of Applied Mechanics, Vol. 85, No. 4, pp. 503515.##[9] Hamey, C.S., Lestari, W., Qiao, P., Song, G. (2004). “Experimental damage identification of carbon/epoxy composite beams using curvature mode shapes”. Structural Health Monitoring, Vol. 3, No. 4, pp. 333353.##[10] Lestari, W., Qiao, P.Z., Hanagud, S. (2007). “Curvature mode shapebased damage assessment of carbon/epoxy composite beams”. Journal of Intelligent Material Systems and Structures, Vol. 18, No. 3, pp. 189208.##[11] Zhu, H., Li, L., He, X.Q. (2011). “Damage detection method for shear buildings using the changes in the first mode shape slopes”. Computers & Structures, Vol. 89, No. (910), pp. 733743.##[12] Perera, R., Fang, S.E., Huerta, C. (2009). “Structural crack detection without updated baseline model by single and multiobjective optimization”. Mechanical Systems and Signal Processing, Vol. 23, No. 3, pp. 752768.##[13] Ghodrati Amiri, G., Seyed Razzaghi, S.A., Bagheri, A. (2011). “Damage detection in plates based on pattern search and genetic algorithms”. Smart Structures and Systems, Vol. 7, No. 2, pp. 117132.##[14] Kang, F., Li, J., Qing X. (2012). “Damage detection based on improved particle swarm optimization using vibration data”. Applied Soft Computing, Vol. 12, No. 8, pp. 23292335.##[15] Saada, M.M., Arafa, M.H., Nassef, A.O. (2013). “Finite element model updating approach to damage identification in beams using particle swarm optimization”. Engineering Optimization, Vol. 45, No. 6, pp. 677696.##[16] Zare Hosseinzadeh, A., Ghodrati Amiri, G., Koo, K.Y. (2016). “Optimizationbased method for structural damage localization and quantification by means of static displacements computed by flexibility matrix”. Engineering Optimization, Vol. 48, No. 4, pp. 543561.##[17] Ghodrati Amiri, G., Zare Hosseinzadeh, A., Seyed Razzaghi, S.A. (2015). “Generalized flexibilitybased model updating approach via democratic particle swarm optimization algorithm for structural damage”. International Journal of Optimization in Civil Engineering, Vol. 5, No. 4, pp. 445464.##[18] Kaveh, A., Zolghadr, A. (2015). “An improved CSS for damage detection of truss structures using changes in natural frequencies and mode shapes”. Advances in Engineering Software, Vol. 80, pp. 93100.##[19] Li, J., Wu, B., Zheng, Q.C., Lim C.W. (2010). “A generalized flexibility matrix based approach for structural damage detection”. Journal of Sound and Vibration, Vol. 329, No. 22, pp. 45834587.##[20] Deng, J.L. (1989). “Introduction to grey system theory”. Journal of Grey System, Vol. 1, No. 1, pp. 124.##[21] Fu, C., Zheng, J., Zhao, J., Xu, W. (2001). “Application of grey relational analysis for corrosion failure of oil tubes”. Corrosion Science, Vol. 43, No. 5, pp. 881889.##[22] Zare Hosseinzadeh, A., Bagheri, A., Ghodrati Amiri, G. (2013). “Twostage method for damage localization and quantification in highrise shear frames based on the first mode shape slope”. International Journal of Optimization in Civil Engineering, Vol. 3, No. 4, pp. 653672.##[23] Box, G.E.P. (1957). “Evolutionary operation: a method for increasing industrial productivity”. Journal of the Royal Statistical Society, Vol. 6, No. 2, pp. 81101.##[24] Lewis, R.M., Torczon, V. (2002). “A globally convergent augmented Lagrangian pattern search algorithm for optimization with general constraints and simple bounds”. SIAM Journal on Optimization, Vol. 12, No. 4, pp. 10751089.##[25] Ge, M., Lui, E.M., and Khanse, A.C. (2010). “Nonproportional damage identification in steel frames”. Engineering Structures, Vol. 32, No. 2, pp. 523533.##]
Estimating of Scour in Downstream of the Water Level Regulation Structures
2
2
Scour in the downstream of hydraulic structures is a phenomenon which usually occurs due to exceeding the velocity or shear stress from a critical level. In this paper by using the laboratory data by Borman Jouline and DeAgostino research, it was tried to get more accurate equations in order to calculate the maximum depth of scour in the downstream of the water level regulation structures. Comparing these equations with the results of the other researchers showed that these equations are much more accurate. After that Artificial neural networks (ANNs) with learning algorithm of error back propagation (BP) were used to estimate maximum water scour depth, and the model which has seven neurons in its hidden layer was produced as the most appropriate model. Finally by using statistical parameters, the ANN model was compared with optimized equations. The results of this study showed high correlation between artificial neural network and proposed equation.
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59
66


Saeed
Farzin
Assistant Professor, Faculty of Civil Engineering, Semnan University, Semnan, Iran
Iran
saeed.farzin@semnan.ac.ir


Mohammad Hosein
Ahmadi
Young Researchers and Elite Club, Beyza Branch, Islamic Azad University, Beyza, Iran
Iran
mohamadh.ahmadi@gmail.com


Rasol
Rajabpur
Young Researchers and Elite Club, Beyza Branch, Islamic Azad University, Beyza, Iran
Iran
rasoul_1360@yahoo.com


Forough
Alizadeh Sanami
Ph.D. Student, Faculty of Civil Engineering, Iran University of Science and Technology, Tehran, Iran
Iran
f.alizadeh@sanru.ac.ir


Kiuomars
Asaii
Young Researchers and Elite Club, Beyza Branch, Islamic Azad University, Beyza, Iran
Iran
adios_amigo9@yahoo.com
Scour estimation
Water level regulation
Error back propagation
Artificial Neural Networks
[[1] Rouse, H. )1940(.“Criteria for similarity in the transportation of sediment.Studies in engineering bull”., Univ. of Iowa, 20, 33–49.##[2] Doddiah, D., Albertson, M. L., and Thomas, R. (1953). “Scour from jets”. Proc., 5th Congr. Int. Assoc. for Hydraulic Res., Minneapolis, September, 161–169.##[3] D’Agostino, V. (1996). “La progett azionedell econtro briglie. Proc., 25th Convegno di Idraulica e Costruzion iIdrauliche”, Torino, September, 3, 107–118 (in Italian).##[4] Schoklitsch, A. (1932). “Kolk bildun gunter Ueberfall strahlen”. Wasser wirtschaft, 24, 341–343 (in German).##[5] Bormann, N. E., and Julien, P. Y. (1991). “Scour downstream of gradecontrol structures”. J. Hydraul. Eng., 117(5), 579–594.##[6] Mason, P. J., and Arumugam, K. (1985). “Free jet scour below dams and flip buckets”. J. Hydraul. Eng., 111(2), 220–235.##[7] D’Agostino, V., and Ferro, V. (2004). “Scour on Alluvial Bed Downstream of GradeControl Structures. J. Hydraul. Eng., 130(1), 24–37.##[8] Jager, C. (1939). “Uber die AehnlichkeitbeiflussaulichenModellversuchen. Wasserkraft und Wasserwirtschaft.34(23/24), 269, (in German).##[9] Hartung, W. (1959). “Die Kolkbildung hinter U berstro¨mtenWeherenimHinblick auf eineBeweglichSturzbettgestaltung. Wasserwirtschaft, 49(1), 309–313 (in German).##[10] Chee, S. P., and Padiyar, P. V. (1969). “Erosion at the base of flip buckets”. Eng. J., 52(111), 22–44.##[11] Chee, S. P., and Kung, T. (1974). “Piletas de derrubioautoformadas”. Proc., 6th Congr. Int. Assoc. for Hydraulic Res., Bogota, Columbia, Paper No. D.7, 1–11.##[12] Martins, R. (1975). “Scouring of rocky riverbeds and freejet spillways”. Int. Water Power Dam Constr., 27(5), 152153.##[13] Chee, S. P., and Yuen, E. M. (1985). “Erosion of unconsolidated gravel beds”. Can. J. Civ. Engrg., 12, 559566.##[14] Yuen, E. M. (1984). “Clearwater scour by high velocity jets”.Thesis presented to the University of Windsor, at Windsor, Ontario, in partial fulfillment of the requirements for the degree of Master of Science.##[15] Akashi, N., and Saitou, T. (1986). ‘‘Influence of water surface on scour from vertical submerged jets.’’ J. Hydrosci. Hydr.Engrg., 5569.##[16] Rajaratnam, N. (1981). “Erosion by plan turbulent jets”. J. Hydraul. Res., 19(4), 339–358.##[17] Albertson, M. L., Dai, Y. B., Jensen, R. A., and Rouse, H. (1950). ‘‘Diffusion of submerged jets”. Trans., ASCE, 115(2409), 639697.##[18] Beltaos, S., and Rajaratnam, N. (1973). “Plane turbulent impinging jets”. J. Hydr. Res., 11(1), 2959.##[19] Yuen, E. M. (1984). “Clearwater scour by high velocity jets”. Thesis presented to the University of Windsor, at Windsor, Ontario, in partial fulfillment of the requirements for the degree of Master of Science.##[20] Neill, C. R. (1968). “Note on initial movement of coarse uniform bed material”. J. Hydr. Res., 6(2), 173176.##[21] Patterson, D. (1996). “Artificial Neural Networks: Theory and Applications. Singapore: Prentice Hall.##[22] Alborzi, M. (2000). “Introduction to Artificial Neural Networks”. Institute of Scientific Publications.##]
Investigation of Geotextile Yarn Effects on Improvement of LongTerm Deformation of Sandy Soil
2
2
Accurate predictions of the amount and the rate of long term deformation of reinforced soils under an applied load are important key issue in geotechnical engineering, in which the deformation of soil develops with time at a state of constant effective stress. Since geosynthetic is generally considered creep sensitive therefore, evaluation of creep behavior of geosynthetic reinforced soil (GRS) is necessary. In this study, to investigate the effect of reinforcing on the creep behavior of sandy clay soil, experimental tests on soil creep of reinforced sandy clay soil with geotextile yarn in one dimensional consolidation test are conducted anddata analysis is explained based on relationship of the change in void ratio (∆e) and coefficient of secondary compression (Cα). Test results indicate that in reinforced water saturated samples with geotextile yarn, with increasing the percent of geotextile yarn creep, deformation decreases and time required for beginning the creep deformation increases.
1

67
79


Alireza
Negahdar
Assistance Professor, Department of Civil Engineering, University of Mohaghegh Ardebili
Iran
negahdar@uma.ac.ir


Shima
Yadegari
Ph.D. Student, Department of Civil Engineering, University of Mohaghegh Ardebili
Iran
yadegari.shima@gmail.com
Creep
GRS
Sandy clay soil
One dimensional consolidation test
Secondary compression
coefficient (Cα)
[[1] Helwany, S.M.B., Wu, J.T.H., Froessl, B. (2003). “GRS bridge abutments – an effective means to alleviate bridge approach settlement”. Geotext. Geomembranes, Vol . 21(3), pp. 177196.##[2] AASHTOAGCARTBA.(1990). “Design Guidelines for Use of Extensible Reinforcements (Geosynthetic) forMechanically Stabilized EarthWalls in PermanentApplications”. In Situ Soil Improvement Techniques, American Association of State and Highway Transportation Officials, Washington, D.C., USA,Vol. 27, pp. 38.##[3] Terzaghi, K., Peck, R. B., and Mesri, G. (1996). “Soil mechanics in engineering practice”. 3rd ed. John Wiley & Sons, New York.##[4] Buisman, A. S. K. (1936). “Results of long duration settlement tests Proceedings”, 1st International Conference on Soil Mechanics and Foundation Engineering, Harvard University, Massachusetts, USA, Vol. 1, pp. 103106.##[5] Taylor, D. W. (1942). “Research on consolidation of clays, Department of Civil Engineering”, MIT, Cambridge, Massachusetts, Vol. 82.##[6] Bjerrum, L. (1967). “Secondary settlement of structures subjected to large variations in live load”. International Union of Theoretical and Applied Mechanics, Symposium on Rheology and Soil Mechanics, Grenoble, France, Vol.1, pp. 460467.##[7] Mcdowell, G. R., De Bono, J. P. (2013). “A new creep law for crushable aggregates”. Géotechnique Letters, Vol. 3, pp. 103107.##[8] Yin, D. S., Wu, H., Cheng, C., Chen, Y. Q. (2013). “Fractional order constitutive model of geomaterials under the condition of triaxial test”. International Journal for Numerical and Analytical Methods in Geomechanics. Vol. 37, pp. 961972.##[9] Hansbo, S. (1975). “Jordmateriallära (Soil material science. In Swedish) ”. Awe/Gebers, Stockholm, Sweden.##[10] Sällfors, G. (2001). “Geoteknik: Jormateriallära, Jordmekanik, 3:e upplagan (Geotechnics: Soil material science”, Soil mechanics, 3rd edition. In Swedish, Chalmers University of Technology, Gothenburg, Sweden.##[11] Larsson, R. (1986). “Consolidation of soft soils”. Swedish Geotechnical Institute, Linköping, Sweden, Vol.29.##[12] Varatharajan, S. (2011). “1D comperssion creep behavior of kaolinite and bentonite clay”, department of civil engineering Calgary, Phd Thesis, Alberta.##[13] Casagrande, A. (1936). “Determination of the preconsolidation load and its practical significance”, Proceedings of International Conference on Soil Mechanics and Foundation Engineering, Vol. 3, pp. 6064.##[14] Zhang, Y., Xue, Y. Q., Wu, J. C., Shi, X. Q. (2006). “Creep model of saturated sands in oedometer tests”. Geotechnical Special Publication, Vol. 150, pp. 328335.##[15] Wang, Z. (2010). “Soil Creep BehaviorLaboratory Testing and Numerical Modeling”. PhD thesis. University of Calgary, Calgary, Alberta, Canada. pp. 212214.##]
Behavior Comparison of Uniaxial Cylindrical Columns Strengthened with CFRP
2
2
In recent years application of CFRP sheets in the strengthening of the concrete circular column has increased numerously. Knowing the exact behavior of concrete cylindrical columns confined with CFRP is of the first order of importance. ISIS Code of Canada has given relations for strength increase of circular columns confined with CFRP sheets, these relations are defined for a specified range of confinement pressure, and for higher confinement pressures there are no relations describing the behavior of the confined specimen. In this paper, cylindrical specimens with different concrete strengths and a variable number of CFRP layers were used. They were modeled in finite element software. After verification of models with laboratory works; results of finite element modeling were compared with ISIS Canada. The analytical results show that with a change in concrete strength the results have a different error from ISIS results. Therefore, for confinement pressure of more than the permissible value of ISIS code, change in the amount of strength increases was studied.
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80
88


Ali
Delnavaz
Assistant Professor, Department of Civil and Surveying Engineering, Qazvin Branch, Islamic Azad University, Qazvin, Iran
Iran
a.delnavaz@qiau.ac.ir


Mohammad
Hamidnia
M.Sc. Structural Eng., Department of Civil and Surveying Engineering, Qazvin Branch, Islamic Azad University, Qazvin, Iran
Iran
hamidnia_mohammad@qiau.ac.ir
Cylindrical specimen
CFRP
Confinement pressure
Uniaxial strength
[[1] Kwan, AKH., Chau, SL., Au, FTK. (2006). “Improving flexural ductility of highstrength concrete beams”. Proc ICE – Struct. Build, 159(6), pp. 339–347.##[2] Paultre, P., Legeron, F., Mongeau, D. (2001). “Influence of concrete strength and transverse reinforcement yield strength on behavior of highstrength concrete columns”. ACI Struct. J., 98(4): pp. 490–501.##[3] Cusson, D., Paultre, P. (1994). “Highstrength concrete columns confined by rectangular ties”. J StructEng,120(3): pp. 783–804.##[4] Xiao, Y. (2004). “Applications of FRP composites in concrete columns”. Adv. Struct. Eng., Vol.7(4): pp. 335–343.##[5] Xiao, Y., Ma, R. (1997). “Seismic retrofit of RC circular columns using prefabricated composite jacketing”. J Struct. Eng., 123(10): pp. 1357–1364.##[6] Ilki, A., Peker, O., Karamuk, E., Demir, C., Kumbasar, N. (2008). “FRP retrofit of low and medium strength circular and rectangular reinforced concrete columns”. J Mater Civ. Eng., 20(2): pp. 169–88.##[7] Ozbakkaloglu, T. (2013). “Compressive behavior of concretefilled FRP tube columns: assessment of critical column parameters”. Eng. Struct., 51: pp. 188–199.##[8] Xiao, Y., Wu, H. (2003). “Compressive behavior of concrete confined by various types of FRP composite jackets”. J Reinf Plast Compos, 22(13): pp. 1187–1201.##[9] Rousakis, TC., Karabinis, AI., Kiousis, PD. (2007). “FRPconfined concrete members: axial compression experiments and plasticity modelling”. Eng. Struct., 29(7): pp. 1343–1353.##[10] Ozbakkaloglu, T., Lim, JC., Vicent, T. (2013). “FRPconfined concrete in circular sections: review and assessment of stress–strain models”. Eng. Struct., 49: pp. 1068–1088.##[11] Idris, Y., Ozbakkaloglu, T. (2013). “Seismic behavior of highstrength concretefilled FRP tube columns”. J. Compos. Constr., Vol. 17 (6) pp. 1943.##[12] Ozbakkaloglu, T. (2013). “Compressive behavior of concretefilled FRP tube columns: assessment of critical column parameters”. Eng. Struct., Vol. 51 pp. 188–199.##[13] Li, Y., Fang, T., Chern, C. (2003). “A Constitutive Model for Concrete Cylinder Confined by Steel Reinforcement and Carbon Fiber Sheet”. pacific conference on earthquake engineering,.##[14] Li, Y., Lin, C., Sung, Y. (2003). “A constitutive model for concrete confined with carbon fiber reinforced plastics”. Mechanics of Materials, Vol. 35, pp 603–619.##[15] ISIS educational module 4. (2004). “An introduction to FRP strengthening of concrete structures”. prepared by ISIS Canada, February 2004.##[16] Majewski, S. (2003). “The mechanics of structural concrete in terms of elastoplasticity”. SilesianPolytechnic Publishing House, Gliwice,.##[17] EN 199211. (2004). “ Eurocode 2 Design of concrete structures  Part 11: General rules and rules for buildings”.##[18] Wang, T., Hsu, T.T.C. (2001). “Nonlinear finite element analysis of concrete structures using newconstitutive models”. Computers and Structures, Vol. 79, Iss. 32, , pp. 2781–2791.##[19] Kmiecik, P., Kaminski, M. (2011). “Modelling of reinforced concrete structures and composite structures with concrete strength degradation taken into consideration”. Archives of civil and mechanical engineering, No. 3.##[20] Abaqus theory manual and users' manual, version 6.10. (2010).##[21] Bouchelaghem, H., Bezazi, A., Scarpa, F. (2011). “Compressive behavior of concrete cylindrical FRPconfined columns subjected to a new sequential loading technique”. Composites: Part B, Vol. 42, pp 1987–1993.##[22] Uya, B., Taoa, Z., Hanc, L. (2011). “Behaviour of short and slender concretefilled stainless steel tubular columns”. Journal of Constructional Steel Research, Vol. 67, pp 360–378.##]