Two M24 bolts. ⢠Class 10.9. Injection bolts were adapted following the recommendation in Annex K of EN 1090-2. Bolts were tightened using the torque method.
Experimental fatigue tests of resin-injected and standard single bolted connections combining S355 mild steel and old material from Eiffel Bridge B. Pedrosa1, J.A.F.O. Correia1,2, C. Rebelo1, A.M.P. De Jesus1, Luís Simões da Silva1
1Department 2Faculty
of Civil Engineering, University of Coimbra, Rua Luis Reis Santos, 3030-788 Coimbra, Portugal of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
Experimental fatigue tests of resin-injected and standard single bolted connections…
Introduction - Motivation • Prolonging lifetime of old steel bridges • Structural elements with corroded areas and cracks • Innovative methods for repairing and strengthening operations • Implementation of resin injected bolted connections • Fatigue analysis
Bruno A. S. Pedrosa
[1]
Experimental fatigue tests of resin-injected and standard single bolted connections…
Introduction - Objectives • Analyse the influence of using structural adhesives on bolted joints concerning its fatigue behaviour • Study the fatigue performance of injected bolted joints for replacing faulty rivets • Apply injection bolts to connect new plates at the corroded areas of structural elements • Compare fatigue experimental data with fatigue design curves proposed in Eurocode 3, part 1-9
Bruno A. S. Pedrosa
[2]
Experimental fatigue tests of resin-injected and standard single bolted connections…
Experimental campaign Single shear connection configuration were tested to assess fatigue resistance when using injected bolts in comparison to non-injected bolts
A total of 24 specimens were tested (number of trials – 3): • 4 tests varying the stress range: High, Medium and Low • 2 tests varying the type of bolt: Injected and Non-Injected Specimens are composed of new steel (S355) and old steel obtained from structural elements of Eiffel bridge
Bruno A. S. Pedrosa
[3]
Experimental fatigue tests of resin-injected and standard single bolted connections…
Bruno A. S. Pedrosa
[4]
Materials - Steel Plates The experimental program includes plates composed of S355 steel and plates machined from original structural elements replaced on Eiffel bridge, Viana do Castelo. Both types of steel plates were manufactured respecting the geometry presented below. Eiffel bridge
Plate’s geometry
The Eiffel bridge was inaugurated in 1886 and was built in puddled iron, which is a material with many heterogeneities, responsible for significant scatter in material properties.
Experimental fatigue tests of resin-injected and standard single bolted connections…
Bruno A. S. Pedrosa
Materials - Bolts
Each test specimen includes: • Two M24 bolts
Injection bolts were adapted following the recommendation in Annex K of EN 1090-2.
Bolts were tightened using the torque method considering the procedure described in EN 1090-2.
[5]
• Class 10.9
As
fub
Fp,C
Mr
[MPa]
[kN]
km -
d
[mm2]
[mm]
[kN.m]
353
1000
247
0,123
24
729
Experimental fatigue tests of resin-injected and standard single bolted connections…
Bruno A. S. Pedrosa
Materials - Resin/Adhesive An epoxy resin was used with a commercial name Sikadur®-52. It is a two-part epoxy resin. Properties: • Low viscosity • Good adhesion to steel • Acceptable mechanical properties
Component A
Component B
Mixture A + B (2:1)
Mechanical properties of Sikadur®-52 Compressive Strength Shear Strength Cure time (+23ºC) (+23ºC) 7 days Aprox. 52 MPa Aprox. 61 MPa
Tensile Strength (+23ºC) Aprox. 37 MPa
[6]
Experimental fatigue tests of resin-injected and standard single bolted connections…
Bruno A. S. Pedrosa
Experimental Procedure Fatigue tests were carried out under load control:
- Force Range, ΔF - Maximum Force, Fmax
Stress Ratio: Frequency:
R=0.1 F =5 Hz
Walterbai Multipurpose Servohydraulic Universal Testing Machine Series LFV 600 kN
[7]
Experimental fatigue tests of resin-injected and standard single bolted connections…
Bruno A. S. Pedrosa
[9]
Experimental results Specimen
Medium Cycle Fatigue
Nf
[Hz]
[MPa]
[MPa]
cycles
108
5
158,5
214,0
325.628
0,1
120
108
5
156,3
211,1
175.045
0,1
120
108
5
152,6
205,8
57.990
x
0,1
120
108
5
160,0
215,9
349.915
0,1
120
108
5
156,6
211,6
29.028
x
0,1
120
108
5
156,7
211,5
277.647
x
Rσ
7 (A7 + F7)
0,1
100
90
5
128,8
173,9
50.725
8 (A8+ F8)
0,1
100
90
5
130,7
176,1
675.759
0,1
100
90
5
133,2
180,0
92.855
0,1
100
90
5
135,6
182,8
574.138
0,1
100
90
5
132,7
179,4
531.952
0,1
100
90
5
129,4
174,8
413.977
9 (A9+ F9) 10 (A10 + F10) 11 (A11 + F11) 12 (A12 + F12)
High Cycle Fatigue
Δσ net
120
5 (A5 + F5) 6 (A6 + F6)
Δσgross
[N]
3 (A3 + F3) 4 (A4 + F4)
f
0,1
1 (A1 + F1) 2 (A2 + F2)
Fmax
ΔF [N]
Resin Injected
x x x
13 (A13 + F13)
0,1
85
76,5
5
111,0
149,5
5.087.414
14 (A14 + 14)
0,1
91,75
82,575
5
121,0
163,0
601.553
15 (A15 + F15)
0,1
89
80,1
5
117,5
158,8
905.699
0,1
89
80,1
5
115,0
155,0
703.018
0,1
89
80,1
5
115,8
156,0
1.289.745
0,1
89
80,1
5
118,6
160,0
1.667.047
16 (A16 + F16) 17 (A17 + F17) 18 (A18 + F18)
x x x
Experimental fatigue tests of resin-injected and standard single bolted connections…
Experimental results •
Specimens with Resin Injected Bolts increase the fatigue strength for high-cycle fatigue
•
Mean S-N curve for Standard Bolts is similar to EC3 detail 90
•
Runouts were excluded from the statistical analysis
Bruno A. S. Pedrosa
[10]
Experimental fatigue tests of resin-injected and standard single bolted connections…
Fatigue Failure Analysis
Bruno A. S. Pedrosa
[11]
Experimental fatigue tests of resin-injected and standard single bolted connections…
Conclusions •
Sikadur®-52 showed good qualities concerning the injection process (low viscosity, rapid cure time)
•
Scatter obtained on experimental results may be a result of inclusions and heterogeneities presented on Eiffel steel plates.
•
Resin improved the fatigue strength of bolted connections in high-cycle regime.
•
The fatigue design curve proposed in EC3 is unsafe for nearly half of the results, however, it has a slope similar to the mean S-N curve obtained for standard bolts.
Bruno A. S. Pedrosa
[12]
Análise à Fadiga de Ligações Aparafusadas Com Adesivos
Bruno A. S. Pedrosa
Thank You!
[13]
Experimental fatigue tests of resin-injected and standard single bolted connections combining S355 mild steel and old material from Eiffel Bridge B. Pedrosa1, J.A.F.O. Correia1,2, C. Rebelo1, A.M.P. De Jesus2, Luís Simões da Silva1
1Department 2Faculty
of Civil Engineering, University of Coimbra, Rua Luis Reis Santos, 3030-788 Coimbra, Portugal of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal