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VIETNAM NATIONAL UNIVERSITY VIETNAM JAPAN UNIVERSITY NGUYEN HUU HOE EVALUATION OF TECHNICAL AND ECONOMIC EFFECTIVENESS OF FIBER REINFORCED POLYMER (FRP) SOLUTIONS IN REPAIRING/STRENGTHENING OF STEEL BRIDGES IN VIETNAM MAJOR: INFRASTRUCTURE ENGINEERING CODE: RESEARCH SUPERVISOR: Associate Prof LUONG XUAN BINH Hanoi, 2019 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com i ACKNOWLEDGEMENT At the very beginning, I would like to express my deepest gratitude to Vietnam National University - Vietnam Japan University (VJU) that gave me the chance to learning and studying VJU gives me a modern international and professional environment The studying opportunity which I had at Vietnam Japan University was a great chance for learning and professional development Therefore, I consider myself a very lucky individual as I was provided with an opportunity to be a part of it I am also grateful for having a chance to meet so many wonderful people and professionals who led me through this studying and researching period The studying time at VJU is a really valuable time for me I express my deepest thanks and gratefulness to Assoc Prof Luong Xuan Binh for his careful and precious guidance which were extremely valuable for my study both theoretically and practically I choose this moment to acknowledge his contribution gratefully I would like to express my deepest gratitude and special thanks to Prof Miyajima in Kanazawa University who in spite of being extraordinarily busy with his duties, took time out to hear, guide and keep me on the correct path and allowing me to carry out my research at his lab and extending during the internship It is my radiant sentiment to place on record my best regards, deepest sense of gratitude to Prof Nguyen Dinh Duc, Prof Hironori Kato, Prof Dao Nhu Mai, Dr Phan Le Binh, Dr Nguyen Tien Dung, and all professors, lecturers from the program of Infrastructures Engineering for their useful orientations and their willing advices to help me complete this thesis Sincerely yours, Nguyen Huu Hoe LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com ii TABLE OF CONTENTS Page LIST OF FIGURES iv LIST OF CHARTS .v LIST OF TABLES vi LIST OF NOMENCLATURES AND ABBREVIATIONS vii UNIT OF SI SYSTEM viii ABSTRACT .1 INTRODUCTION The necessary of the study 2 The objective of the study .2 Methodology The object and scope of the study The layout of the thesis Chapter : LITERATURE REVIEW Chapter : OVERVIEW OF TECHNICAL ISSUES OF REPAIRING AND STRENGTHENING STEEL BRIDGE STRUCTURE IN VIETNAM .7 2.1 Typical forms of damages of steel bridge structure in Vietnam .7 2.2 Traditional solutions to repair and reinforce steel bridges 2.2.1 Repair solutions 2.2.2 Some methods of reinforcing the steel span structure 13 2.3 Technical requirements of steel bridge repair and reinforcement 13 2.4 Develop criteria for selecting FRP materials for the repair and reinforcement of steel bridges .14 Chapter : SOME EXPERIMENTAL RESEARCHES USING FRP MATERIALS IN REPAIRING, STRENGTHENING STEEL STRUCTURE AND ANALYSIS OF TECHNICAL EFFICIENCY OF SOLUTIONS 16 3.1 Experiment 1: Experiment on glue resistance of TYFO WS 16 3.1.1 Experimental purpose .16 3.1.2 Experimental setup 16 3.1.3 Processing experimental data 23 3.1.4 Comment and conclusion on experimental results 27 3.2 Experiment 2: Bending test of steel samples reinforced with FRP materials 28 3.2.1 Experimental purpose .28 3.2.2 Experimental setup 28 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com iii 3.2.3 Processing experimental data 33 3.2.4 Comment and conclusion on experimental results 41 3.3 Conclusion of technical efficiency 42 Chapter : EVALUATE THE ECONOMIC EFFICIENCY OF THE SOLUTIONS USING FRP MATERIALS ON REPAIRING STEEL BRIDGE STRUCTURE IN VIETNAM, CASE STUDY LONG BIEN BRIDGE 44 4.1 Causes and deterioration of Long Bien Bridge .44 4.1.1 Overview of history, operation of Long Bien Bridge 44 4.1.2 Damaged condition of the Long Bien bridge 46 4.1.3 Damaged classification: 48 4.2 Protection and reinforcement measures have been used .49 4.2.1 Use U-shaped steel plate to cover the collar beam .49 4.2.2 Use steel plates to compensate for corrosion, puncture with welding or rivets for bonding Then use special paint to paint on .51 4.2.3 Replace collar beam by new one 52 4.3 Develop solutions for repairing and strengthening Long Bien Bridge 53 4.3.1 The advantages of repair and reinforcement with FRP materials .53 4.3.2 Select FRP materials following the criteria and technical requirements: .53 4.3.3 Calculation and design of reinforcement solutions for Long Bien bridge collar beams using FRP-Tyfo materials .54 4.4 Estimate the unit price for methods of repairing and reinforcement collar beams of Long Bien bridge 63 4.4.1 Bases for calculation of repair and reinforcement prices .63 4.4.2 Volume of repair and reinforcement methods 66 4.4.3 Unit price for methods of repairing and reinforcement collar beams of Long Bien bridge 69 4.5 Analysis, evaluation of economic efficiency 77 CONCLUSION 79 REFERENCES 80 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com iv LIST OF FIGURES Page Figure 2.1 Repair the crack in steel structures Figure 2.2 Corrosion in steel structures 10 Figure 2.3 Flatting steel structures 12 Figure 3.1 Model of pulling test on compressed tractor multimeter HFM 16 Figure 3.2 Simulation image of Tyfo WS foundation adhesion structure .19 Figure 3.3 Creating test samples for pulling test 20 Figure 3.4 Sample after maintenance .21 Figure 3.5 Sample of test before pulling 21 Figure 3.6 Pull the sample on the machine 22 Figure 3.7 Experimental samples were split when pulled 22 Figure 3.8 Model of bending reinforced thick steel beams 30 Figure 3.9 Model of bending reinforced thin steel beams with two layers 30 Figure 3.10 Model of bending reinforced thin steel beams with three layers 30 Figure 3.11 Thick beams and thin beams after maintenance 31 Figure 3.12 Bending steel beams on compressors with 32 Figure 3.13 Model of bending steel beams 33 Figure 4.1 Picture of Long Bien Bridge 44 Figure 4.2 Rail way of Long Bien Bridge 45 Figure 4.3 Horizontal/collar beam of Long Bien Bridge 46 Figure 4.4 Damaged image of the upper flange .46 Figure 4.5 Describe damage on the upper flange .47 Figure 4.6 The damage of web of beam of Long Bien Bridge .47 Figure 4.7 Description of web’s damage 47 Figure 4.8 Description of lower flange’s damage 48 Figure 4.9 U-shape steel structure 50 Figure 4.10 Method of steel plate and protective coating 51 Figure 4.11 Construction method to replace collar beams .52 Figure 4.12 Original I section and force components 55 Figure 4.13 Cross section severely damaged by 20% and forces 58 Figure 4.14 Cross section damaged by 10% and forces 60 Figure 4.15 Cross section damaged by 5% and forces .62 Figure 4.16 The figure shows the size of the collar beam 66 Figure 4.17 The area reinforced by gluing stell plates method 67 Figure 4.18 The area reinforced by FRP material method .69 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com v LIST OF CHARTS Page Chart 3.1 Experiment to determine the pulling force -Sample 23 Chart 3.2 Experiment to determine the pulling force -Sample 23 Chart 3.3 Experiment to determine the pulling force -Sample 24 Chart 3.4 Experiment to determine the pulling force -Sample 25 Chart 3.5 Experiment to determine the pulling force -Sample 26 Chart 3.6 Experiment to determine the pulling force -Sample 26 Chart 3.7 Load and deformation relationship of bending test 34 Chart 3.8 Force and deflection relationship of thin beams .37 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com vi LIST OF TABLES Table 2.1 Criteria of FRP material 15 Table 3.1 Record the test results of pulling test samples without sand blasting .25 Table 3.2 Record the test results of pulling test 27 Table 3.3 Experimental data of thick steel beam bending test 33 Table 3.4 Maximum stress sheet of steel and FRP sheets 35 Table 3.5 Compare the load value of beams at the same deflection 35 Table 3.6 Table of data for calculation of thin beams reinforced with FRP sheet 37 Table 3.7 Calculate the maximum stress on thin steel beams 38 Table 3.8 The maximum stress table on thin beams is reinforced with layers 39 Table 3.9 The maximum stress table on thin beams is reinforced with layers 41 Table 4.1 Parameters of Tyfo SCH - 41 57 Table 4.2 Parameters of Epoxy Tyfo S .57 Table 4.3 Calculation for number of FRP layer (Group I-20%) .59 Table 4.4 Calculation for number of FRP layer (Group II-10%) .61 Table 4.5 Calculation for number of FRP layer (Group III-5%) 62 Table 4.6 Price of materials, labours, equipments 64 Table 4.7 Calculate the weigh of horizontal/collar beam 66 Table 4.8 Volume of steel plate use for a reinforced collar beam 68 Table 4.9 Volume of FRP materials use for a reinforced collar beam .69 Table 4.10 Unit price for production and manufacturing collar beams 70 Table 4.11 Unit price for dismantling, removing horizontal/collar beam 71 Table 4.12 Unit price for install horizontal/collar beam 71 Table 4.13 Unit price of paint steel by normal paint 72 Table 4.14 Unit price for replace horizontal/collar beam and painting 72 Table 4.15 Unit price for attach/glue steel plates 73 Table 4.16 Unit price for reinforced collar beam by gluing steel plate method .73 Table 4.17 Unit price for cleaning steel surface before attachment 74 Table 4.18 Unit price for sticking glass fiber on the steel 75 Table 4.19 Unit price for sticking carbon fiber 75 Table 4.20 Unit price for painting surface of FRP layer with Tyfo U Coating 76 Table 4.21 Unit Price for reinforcement using FRP (for one collar beam) 76 Table 4.22 The cost of methods within 50 years 77 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com vii LIST OF NOMENCLATURES AND ABBREVIATIONS A cross-sectional area b width of rectangle d diameter section E Young module of elasticity FRP fiber reinforcement Polymer J moment of inertia h height L length M bending moment P load effect S static moment Y coordinates of the point of stress versus the neutral axis ε deformation σ stress σch the yield stress of steel σgh the yield stress of FRP n number of FRP layer LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com viii UNIT OF SI SYSTEM Intensity of force mega pascal MPa Length millimeter mm Area squared millimeter mm2 Density gram to cubed centimeter g/cm3 Force newton N Moment of mass cubed millimeter mm3 Moment of inertia millimeter to the power of four mm4 Temperature Celsius o Stress newton to millimeter square N/mm C LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com ABSTRACT Through the experience results, the thesis has useful comments on the quality of the processing of steel structure surface to the adhesion effect between epoxy glue and reinforced structure This is an important basis to build instructions on construction technology steps to apply FRP materials on steel structures Experimental research has also evaluated the effect of reinforcing the bearing capacity of FRP materials for steel structures Through a survey of the deterioration and degradation of Long Bien Bridge, the thesis has proposed a solution to apply FRP materials to repair, reinforce collar beams within the range of train operation of Long Bien bridge Find out some advantages and disadvantages of using the FRP material method and other traditional methods have been used The thesis has proposed a set of criteria to select FRP materials suitable for repairing and strengthening requirements of steel structures in Long Bien Bridge project in particular and steel bridges in Vietnam in general Research proposed a method of calculation to determine the number of layers of FRP material to reinforce bending capacity for the collar beam’s section of Long Bien Bridge (corresponding to the level of damages 20%, 10%, and 5%) Based on norms, documents, announcements of Vietnam, research has estimated the unit price for three methods of reinforcement, repair for a horizontal/collar beam (replacing collar beams, gluing steel plates and using FRP material) Thereby, comparing the effectiveness of the method of using FRP with the other methods Through the calculation of unit prices and comparative analysis, research point out the economic efficiency of the solution using FRP materials, especially if considering the more effective aspects, and other advantages of FRP such as: not have to stop operation, protecting human health and protect the environment LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com Table 4.8 Volume of steel plate use for a reinforced collar beam No Name of component Upper Flange Girder Web (2 sides) Lower Flange Length Width Thick Volume Density (mm) (mm) (mm) (m3) (Kg/m3) 14280 240 11 0.038 7850 Weigh (Ton) 0.296 9600 14600 0.769 0.303 928 240 11 11 Total 0.098 0.039 7850 7850 1.368 4.4.2.3 Bonding with FRP material method According to the internal force diagram of the collar beam, the area in the middle of the collar beam span and the range of the running train is the most effective Besides, the survey also shows that this area is also damaged most by corrosion To meet the economic and technical requirements, the research recommended that the scope and volume of FRP gluing be as follows: • Paste layer of glass fiber (According to the structural requirements and protect steel beam): + The lower flange: (2900 + 2000 + 4800 + 2000 + 2900) mm x 240mm; + Girder web (within the range between two longitudinal beams-running train area): (4800mm x 928mm) x sides; + Upper flange (within the range between two longitudinal beams-running train area): 4800mm x 240mm; • Paste layers of carbon fiber (As required for bearing - as calculated in section 4.3.3): Only stick on the under of lower flange of the collar beam, stick on the previously glued glass fiber layer (within the range between two longitudinal beamsrunning train area): 4800mm x 240mm x 5layers 68 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com A Glass fiber layer A carbon fiber layers A A Glass fiber layer carbon fiber layers Figure 4.18 The area reinforced by FRP material method Table 4.9 Volume of FRP materials use for a reinforced collar beam No Name of component Glass fiber Length Width Area (m) (m) (m2) Carbon fiber Length Width Area (m) (m) (m2) Upper Flange 4.800 0.240 1.15 - - - Girder Web 4.800 0.928 8.91 - - - 14.600 0.240 3.50 13.56 4.800 0.240 5.76 5.76 Lower Flange Total 4.4.3 Unit price for methods of repairing and reinforcement collar beams of Long Bien bridge 4.4.3.1 The replacing collar beam method Job compositions: 1) Production and manufacturing collar beams; (Table 4.10) Pursuant to Decision No 1778 / BXD-VP, job’s number code SX.1421 69 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com 2) Removing, dismantling old collar beams; (Table 4.11) Pursuant to Decision No 1778 / BXD-VP, job’s number code XT.2210 3) Install new collar beams; (Table 4.12) Pursuant to Decision No 1778 / BXD-VP, job’s number code XT.2110 4) Painting to protect collar beams; (Table 4.13) Pursuant to Decision No 1149 / QD-BXD, job’s number code SE.21310 The detail of each job composition cost see tables below: Table 4.10 Unit price for production and manufacturing collar beams VND/Ton Work item I II Material Steel shape Steel plate Oxy Acetylene Botl and loi Other materials Labour Labour 4,3/7 III Equipment Hand Drill 4,5kW Air Compressor 4m3/minute Crawler Crane 10T Other equipments A Direct cost (I+II+III) Unit Quantity Price Amount 15,189,649 5,220,855 8,826,705 90,000 33,500 295,272 723,316.61 8,364,330 Kg Kg bottle bottle each % 386.73 653.83 2.00 0.67 15.58 5% 13,500 13,500 45,000 50,000 18,952 manday 31.98 261,549 8,364,330 Shift 3.66 251,317 3,197,116 919,820 Shift 2.17 875,399 1,899,616 Shift % 0.19 1% 1,821,184 346,025 31,655 26,751,094 70 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com Table 4.11 Unit price for dismantling, removing horizontal/collar beam VND/Ton Work item I II III A Material Wooden rail Oxy Acetylene Other materials Labour Labour 4,0/7 Equipment Crawler Crane 16T Crawler Crane 25T Electric Winch 5T Crawler Crane gate 30T Other equipments Direct cost (I+II+III) Unit each bottle bottle % man-day Shift Shift Shift Shift % Quantity Price 0.12 1.48 0.49 5% 120,000 45,000 50,000 9.5 248,121 0.17 0.28 1.12 1.12 5% 2,307,321 2,710,160 262,143 1,141,389 Amount 110,775 14,400 66,600 24,500 5,275.00 2,357,150 2,357,150 2,801,643 392,245 758,845 293,600 1,278,356 78,598 5,269,568 Table 4.12 Unit price for install horizontal/collar beam VND/Ton Work item Unit Quantity Price I Amount Material Wooden rail Botl and loi Other materials II Labour each each % 0.17 17.5 5% 120,000 18,952 Labour 4,5/7 manday 17.5 270,501 4,733,760 2,307,321 2,710,160 262,143 1,141,389 1,833,957 276,879 650,438 393,215 470,252 43,173 III Equipment Crawler Crane 16T Crawler Crane 25T Electric Winch 5T Crawler Crane gate 30T Other equipments A Direct cost (I+II+III) Shift Shift Shift Shift % 0.12 0.24 1.5 0.412 5% 369,663 20,400 331,660 17,603.00 4,733,760 6,937,380 71 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com Table 4.13 Unit price of paint steel by normal paint (1 primer layer, colour paint layers) VND/m2 Work item I Unit Quantity Price (VND) Material Amount 45,109 Paint Alkyd Nishu Deluxe (anti-rust, anti-corrosion) Colour Paint Alkyd Nishu Deluxe (2 layers-colour paint) Other materials II Labour 1 Labour 4,0/7 Kg 0.143 92,800 Kg 0.24 130,800 % 1.0% manday 0.06 13,270 31,392 447 14,887 248,121 A Direct cost (I+II) 14,887 59,996 Table 4.14 Unit price for replace horizontal/collar beam and painting VND/collar beam No Work item Unit price for manufacturing horizontal/collar beam Unit price for dismantling, removing horizontal/collar beam Unit price for install horizontal/collar beam Painting collar/ horirontal beam Unit Quantity Price (VND) Amount ton 1.52 ton 1.52 5,269,568 ton 1.52 6,937,380 10,567,306 m2 32.75 Total 26,751,094 40,748,380 59,996 8,026,825 1,964,910 61,307,421 4.4.3.2 The gluing steel plate method Job compositions: 1) Attach/glue steel plates; (Table 4.15) Pursuant to Decision No 1149 / QD-BXD, job’s number code SB.52112 72 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com 2) Painting to protect collar beams; (Table 4.13) Pursuant to Decision No 1149 / QD-BXD, job’s number code SE.21310 The detail of each job composition cost see tables below: Table 4.15 Unit price for attach/glue steel plates VND/Ton Work item I Material Steel shape Steel plate Oxy Gas Abrasive stone Soldering Stick Wood Scaffold steel Other materials Labour Labour 4,5/7 Equipment Grinding Machine2,7kW Welding Machine 23kW Jacking Device, Type 100T Other equipments Direct cost (I+II+III) II III A Unit Quantity Price Amount Kg Kg bottle Kg Pellet Kg m3 Kg % 730 13,500 300 13,500 3.1 45,000 7.75 17,692 0.35 15,000 28 19,800 0.045 2,000,000 7.5 13,500 3% man-day 34.25 270,501 0.77 6.22 2.35 10% 204,001 323,733 244,141 Shift Shift Shift % 15,380,491 9,855,000 4,050,000 139,500 137,115 5,250 554,400 90,000 101,250 447,975.46 9,264,645 9,264,645 3,018,875 157,081 2,013,619 573,731 274,443 27,664,010 Table 4.16 Unit price for reinforced collar beam by gluing steel plate method VND/collar beam No Work item Unit price for attach/glue steel plates Painting to protect collar beams Total Unit Quantity ton 1.37 m2 32.75 Price (VND) Amount 27,664,010 37,838,391 59,996 1,964,910 39,803,300 73 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com 4.4.3.3 Bonding with FRP material method Estimate for the beam which has section area is reduced by 20% Job compositions: 1) Cleaning, sand blasting before pasting; (Table 4.17) Pursuant to Decision No 1149 / QD-BXD, job’s number code SE.21411 2) Paste glass fiber layer (1 layer); (Table 4.18) Pursuant to Decision No 1149 / QD-BXD, job’s number code SE.21423 3) Paste carbon fiber (5 layers); (Table 4.19) Pursuant to Decision No 1149 / QD-BXD, job’s number code SE.21422 4) Paint surface of FRP layer with Tyfo U Coating; (Table 4.20) Pursuant to quote of VSBCO company 5) Paint the area was not reinforced with FRP, use normal paint; (Table 4.13) Pursuant to Decision No 1149 / QD-BXD, job’s number code SE.21310 The detail of each job composition cost see tables below: Table 4.17 Unit price for cleaning steel surface before attachment VND/m2 Work item Material Abrasive stone II Labour Unit Quantity Price (VND) I III A Labour 4,0/7 Equipment Grinding Machine 1kW Air Compressor 600 m3/h Direct cost (I+II+III) Amount Pellet 0.464 15,000 6,960 6,960 158,549 manday 0.639 248,121 158,549 195,647 875,399 108,308 94,302 14,006 273,818 Shift Shift 0.482 0.016 74 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com Table 4.18 Unit price for sticking glass fiber on the steel (first layer-structure requirements) VND/m2 Work item I Material Glass fiber Tyfo SEH25A Tyfo WS Multi-purpose Epoxy Other materials and rate of loss Unit Quantity Price (VND) m 1.05 191,008 1,203,032 200,558 Set 0.06 15,849,000 990,563 % 1.0% 11,911 II Labour 87,090 Labour 4,0/7 A Amount manday 0.351 248,121 Direct cost (I+II) 87,090 1,290,123 Table 4.19 Unit price for sticking carbon fiber VND/m2 for layer Work item I Material Carbon fiber SCH41 Tyfo S Saturant Epoxy Other materials and rate of loss Unit m2 Set % Quantity Price (VND) 1.05 2,200,716 0.05 15,849,000 0.2% A Direct cost (I+II) 3,181,594 2,310,752 864,491 6,350 II Labour Labour 4,0/7 Amount 83,617 manday 0.337 248,121 83,617 3,265,210 75 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com Table 4.20 Unit price for painting surface of FRP layer with Tyfo U Coating VND/m2 Work item I Unit Quantity Price (VND) Material Tyfo U coating paint Other materials lit % 0.175 1.0% 986,160 II Labour 174,741 173,011 1,730 4,962 Labour 4,0/7 A Amount manday 0.02 248,121 Direct cost (I+II) 4,962 179,703 Table 4.21 Unit Price for reinforcement using FRP (for one collar beam) VND/collar beam No A Work item Cleaning surface of steel collar beam before attachment glass fiber Stick glass fiber on the steel (first layer-structure requirements) Stick carbon fiber SCH 41 on the steel (5 layers) Paint surface of FRP layer with Tyfo U Coating Paint other areas which were not reinforced by FRP Direct cost (1+2+3+4+5)) Unit Quantity Price (VND) Amount m2 13.56 273,818 3,714,281 m2 13.56 1,290,123 17,500,254 m2 5.76 3,265,210 18,807,612 m2 10.06 179,703 1,807,956 m2 19.19 59,996 1,151,072 42,981,175 76 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com 4.5 Analysis, evaluation of economic efficiency According to Section 4.4, research have calculated the cost for reinforcing collar beams by replacing, gluing steel plates and using FRP materials, to analyze the effectiveness of solutions considering the maintenance, repair costs, periodic treatment for a period of 50 years In particular, in addition to the cost of initial repair and reinforcement, it is necessary to charge additional costs for periodic paint protection Normal every years the bridge need to be painted to protect the steel structures using normal paint Epoxy Paint is 50 years Look at the cost table below: Table 4.22 The cost of methods within 50 years VND/1collar beam No Name of methods Method 1: Replace the old collar beam by new one Method 2: Use steel plate Method 3: Use FRP material ∆C(3-1)/C3*100% =(C3-C1)/C3*100% ∆C(3-2)/C3*100% =(C3-C2)/C3*100% Initial investment repair costs The cost of regular repair and maintenance 61,307,421 32,748,493 94,055,914 39,803,300 32,748,493 72,551,793 42,981,175 20,992,489 63,973,664 Total -43% -47% 7% -20% Note: C1- The cost of method 1; C2-The cost of method 2; C3-The cost of method 3; 77 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com Commendation: From the above cost table research pointed out: For initial repair investment costs: The using FRP material method is cheaper than replacing the old collar beam by 43% but more expensive than the gluing steel plate method by 7% When considering regular maintenance and repair costs after 50 years: The using FRP material method is cheaper than replacing the old collar beam method by 47% and is also cheaper than the gluing steel plate method by 20% Therefore, the solution of using FRP material is really economical effectiveness If analyze some of the other benefits of the following, the solution to using FRP materials is of great benefit: 1) The cost of stopping using, operation during construction time (every day there are thousands of motorbikes and dozens of trains passing through Long Bien Bridge, so the cost of traffic stop is huge) 2) Cost impact on people’s health, occupational safety and protect the environment (FRP solution is a simple construction method, does not require big, heavy equipment, so in the construction process will be very safe for people and construction structures) 3) Costs for beauty, aesthetics (FRP solutions not increase structural weight, easy to use paint to decorate and create beauty for bridges) For collar beams which have section area is reduced by 5% or 10%, the replacement method, or the gluing steel plate method is not economically efficient than the method of using FRP materials (just need to paste or layers of FRP to both protect the structure from corrosion, while ensuring safety requirements for structure) 78 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com CONCLUSION When changing the surface roughness of the sample by sand blasting, the tensile strength of the sample is nearly doubled compared to the original sample, the rougher the surface, the higher the tensile strength of the sample Therefore, roughness and surface cleanliness are important factors for the tensile strength of the sample The bending capacity of steel beam structure reinforced by FRP material is extremely impressive The solution of using FRP material is really economical effectiveness If research analyze some other aspects such as the cost of stopping using, operation during construction time, maintenance cost, safety and protect the environment cost, the solution to using FRP materials is great benefit Research propose the government to allow the application of these research results to repair and reinforce the collar beam of Long Bien bridge, thereby further evaluating the economic efficiency and technical efficiency of the solution as a basis for proposing the application of research results for steel bridge in Vietnam 79 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com REFERENCES ACI Committee, & International Organization for Standardization (2008) Building code requirements for structural concrete (ACI 318-08) and commentary American Concrete Institute Aydin, H., Gravina, R J., & Visintin, P (2018) A partial-interaction approach for extracting FRP-to-concrete bond characteristics from environmentally loaded flexural tests Composites Part B: Engineering, 132, 214-228 Bakis, C E., Ganjehlou, A., Kachlakev, D I., Schupack, M., Balaguru, P., Gee, D J., & Kliger, H S (2002) Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures Reported by ACI Committee, 440(2002) Fardis, M N., & Khalili, H (1981, November) Concrete encased in fiberglassreinforced plastic In Journal Proceedings (Vol 78, No 6, pp 440-446) Fleming, C J., & King, G E M (1967) The development of structural adhesives for three original uses in South Africa Bulletin rilem, 1967(37), 241-251 Foster, S K., & Bisby, L A (2008) Fire survivability of externally bonded FRP strengthening systems Journal of composites for construction, 12(5), 553-561 Ganesan, K., & Vettivel, S C (2017) Performance of BFRP and GFRP Hollow Circular Steel columns subjected to axial compression loads JOURNAL OF ADVANCES IN CHEMISTRY, 13(7), 6313-6321 Ghadir Mehramiz and Kambiz Narmashiri (2014) Shear Performance of Strengthened Steel Beams: A Comparison between using FRP Composites and Steel Sheets In MAGNT research Report (ISSN.1444-8939) Vol.2 (6): PP.825-838 Katsumata, H., Kobatake, Y., & Takeda, T (1987, May) ‘A study on the strengthening with carbon fiber for earthquake-resistant capacity of existing reinforced 80 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com concrete columns In Proc., Workshop on Repair and Retrofit of Existing Structures (pp 1816-1823) Kumar, P., Chandrashekhara, K., & Nanni, A (2004) Structural performance of a FRP bridge deck Construction and Building Materials, 18(1), 35-47 Mazzotti, C., Bilotta, A., Carloni, C., Ceroni, F., D’Antino, T., Nigro, E., & Pellegrino, C (2016) Bond between EBR FRP and concrete In Design procedures for the use of composites in strengthening of reinforced concrete structures (pp 3996) Springer, Dordrecht Motavalli, M., & Czaderski, C (2007, October) FRP composites for retrofitting of existing civil structures in Europe: state-of-the-art review In International Conference of Composites & Polycon., American Composites Manufacturers Association Tampa, FL, USA Nanni, A (1995) Concrete repair with externally bonded FRP reinforcement Concrete International, 17(6), 22-26 Narmashiri, K., Jumaat, M Z., & Sulong, N R (2010) Shear strengthening of steel Ibeams by using CFRP strips Scientific Research and Essays, 5(16), 2155-2168 Phares, B M., Wipf, T J., Klaiber, F W., Abu-Hawash, A., & Lee, Y S (2003, August) Strengthening of steel girder bridges using FRP In Proceedings of the 2003 mid-continent transportation research symposium, Ames, Iowa (pp 1-12) Rostasy, F S (1987) Bonding of steel and GFRP plates in the area of coupling joints Braunschweig, Germany: Federal Institute for Mater Testing Teng, J G., Yu, T., & Fernando, D (2012) Strengthening of steel structures with fiberreinforced polymer composites Journal of Constructional Steel Research, 78, 131-143 81 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com Triantafillou, T C., & Plevris, N (1992) Strengthening of RC beams with epoxybonded fibre-composite materials Materials and Structures, 25(4), 201-211 Tường, N Q (2007) Sửa chữa gia cố cơng trình bê tơng cốt thép phương pháp dãn nhờ sử dụng vật liệu FRP Tạp chí Phát triển Khoa học Cơng nghệ, 10(10), 39-51 [Tuong, N.Q (2007) Repairing and strengthening reinforced concrete works by use FRP material method Journal of Science and Technology Development, Volume 10 (10) 39-51 Wolf, R., & Miessler, H J (1989) HLV-Spannglieder in der Praxis Erfahrungen Mit Glasfaserverbundstaben, Beton, 2, 47-51 82 LUAN VAN CHAT LUONG download : add luanvanchat@agmail.com ... development of technical standards and design guidelines ACI440R in 2000 for using FRP materials In the past ten years, glass fiber reinforced polymer materials and soft carbon fiber reinforcement... OVERVIEW OF TECHNICAL ISSUES OF REPAIRING AND STRENGTHENING STEEL BRIDGE STRUCTURE IN VIETNAM 2.1 Typical forms of damages of steel bridge structure in Vietnam Some major damages often appear in the... between reinforced steel beams and un -reinforced beams: +) Thin steel beams reinforced with two layers of carbon fiber have the load bearing capacity increased about 138.7% compared to un-reinforced
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