Evaluation and Repair of Wrought Iron and - Purdue e-Pubs ...

More documents

Recommendations

Info

$MATH 050 Prealgebra Practice Test 1 Introduction to Algebra ...$

$MATH 050 Financial Project Making Money WORK for You! 1. Use a ...$

22The practice of restoring historic bridges for pedestrian use is very commonthrough out the country. This practice is viewed by many as an effective compromisebetween keeping the historical validity of a bridge and keeping it structurally safe to use.Francis E. Griggs, Jr is the director of Historic Bridge Programs at Clough, Harbour &Associates LLP. He has rehabilitated and reconstructed many historic bridges in thismanner. One bridge in particular is an 1864 Moseley Wrought Iron Bridge that wasmoved to the Campus of Merrimack College in N. Andover, MA (Griggs, 1997).2.3.2 Carroll Road Bridge, Maryland, 1879The Carroll Road Bridge was a wrought iron Pratt through bridge that spanned 92feet and was constructed in Baltimore County, Maryland in 1879. This bridge consistedof two wrought iron trusses with a wooden deck supported by stringers. The upper andlower chords of the trusses are made up of eyebars with pin connections. Pin connectionsare a typical type connection found in many historical truss type bridges.The Baltimore County Department of Public Works decided to rehabilitate theCarroll Road Bridge in order to preserve the historic character and upgrade the live loadcapacity of the bridge to modern vehicle standards. This preservation project is explainedin the paper Upgrading and Recycling of Pin-Connected Truss Bridge by PinReplacement by Shahin Taavoni (1994).In the initial phase of the study, a visual inspection of the bridge was completed.Also material shavings where taken from the bridge to determine the type of metal in thebridge. Chemical analysis results determined that the material was wrought iron. Duringthe visual bridge investigation it was found that the pin connections on the bridge werenot acting symmetrically.
23The lack in symmetry found at the pin connections was a result of dynamic effectsof the live load and past repairs. Corrosion and fatigue could also lead to movement inthe eyebars but was not considered to be an issue for this bridge. An analysis of the lackof symmetry and resultant effects determined that the pins needed to be replaced with ahigher strength material and the eyebars moved back to a symmetrical position. Thiswould ensure that the pins would not experience an unsafe amount of shear, that theeyebars would all carry the load equally.The rehabilitation of the bridge consisted of taking apart the trusses andreassembling them with higher strength pins. Members added during past repairs werealso removed. Many of these past repairs involved the addition of a third component in aprevious two component member. To sustain the higher load the third component wouldbe removed and the two component member would be replaced with a stronger twocomponent material. Finally, spacers were added to the pin connection to ensure thatsymmetry would be maintained in the future.Rehabilitation using the pin replacement method turned out to be efficient,expeditious and economical according to Taavoni. It could also be easily adapted tomany other historic truss bridges that have similar pin connections.2.3.3 Chestnut Ford Bridge and Hubby Bridge, Iowa, circa 1900Construction on the Des Moines River in Iowa lead to the removal of five iron pinconnected truss bridges in that area. The first of these bridges, the Chestnut Ford Bridge,was subjected to service load testing, and supplementary static and fatigue tests of tensioneyebars taken from the bridge. The second bridge, the Hubby Bridge, was also subjectedto service load testing and eyebar laboratory testing, but also went through an ultimateload test. The paper Service Load and Fatigue Tests on Truss Bridges by Hotten A.
Page 1 and 2: Purdue UniversityPurdue e-PubsJTRP
Page 3: 1. Report No. 2. Government Accessi
Page 6 and 7: epairing a bent wrought iron tensio
Page 8 and 9: vPageCHAPTER 3TEST PROCEDURES FOR M
Page 10 and 11: ixLIST OF FIGURESFigurePageFigure 1
Page 12 and 13: xiFigurePageFigure 3.30 Top View of
Page 14 and 15: xiiiFigurePageFigure 5.12 Typical T
Page 16 and 17: xvAppendix FigurePageFigure D.7 Ini
Page 18 and 19: viiiAppendix TablePageTable A.5 Det
Page 20 and 21: iiiThe authors would also like to t
Page 22 and 23: 2but also what material properties
Page 24 and 25: 4microstructure of the metal. The c
Page 26 and 27: 62. LITERATURE SEARCHBefore experim
Page 28 and 29: 8imperfections, the performance of
Page 30 and 31: 10wrought iron. Adding the slag aft
Page 32 and 33: 12method for manufacturing wrought
Page 34 and 35: 14patents for their process and tra
Page 36 and 37: 16This method of testing of structu
Page 38 and 39: 18plot of this percent elongation d
Page 40 and 41: 20significant variation in the perc
Page 44 and 45: 24Elleby, Wallace W. Sanders, F. Wa
Page 46 and 47: 26From all the surveys that were di
Page 48 and 49: 28Table 2.1 Average Ultimate Streng
Page 50 and 51: 30Figure 2.3 Wrought Iron “Sponge
Page 52 and 53: 32Histogram of Kirkaldy Wrought Iro
Page 54 and 55: 34Percent Occurance in Range - %45.
Page 56 and 57: 3660Combined Wrought Iron BarsTensi
Page 58 and 59: 38The Bell Ford Bridge consisted of
Page 60 and 61: 40Two. These samples were taken fro
Page 62 and 63: 42specimens were of constant cross
Page 64 and 65: 44Along with rectangular tensile co
Page 66 and 67: 46After the initial test loading wa
Page 68 and 69: 483.6 Fatigue TestingTo develop a b
Page 70 and 71: 50The final specimen category consi
Page 72 and 73: 52This analysis was completed using
Page 74 and 75: 54After the initial test was comple
Page 76 and 77: 56completed, but before the surface
Page 78 and 79: 58readings, load cell readings and
Page 80 and 81: 60Figure 3.3 Donated Eyebars 4 and
Page 82 and 83: 62Figure 3.7 Heated Areas in Blue o
Page 84 and 85: 64Figure 3.11 Detail Used in Groove
Page 86 and 87: 66900080007000y = 27.153xR 2 = 0.99
Page 88 and 89: 68Figure 3.19 Charpy Impact Testing
Page 90 and 91: 70Figure 3.23 Eyebar Connection in
Page 92 and 93:
72Figure 3.27 Eyebar A After Filler
Page 94 and 95:
74Figure 3.31 Side View of Finished
Page 96 and 97:
76Figure 3.35 Front View of Eyebar
Page 98 and 99:
78strength from the existence of pe
Page 100 and 101:
80The carbon content present in the
Page 102 and 103:
82value may not be very accurate bu
Page 104 and 105:
84strengths was found to be 29,940
Page 106 and 107:
86wrought iron bars were investigat
Page 108 and 109:
88stresses are induced. These perma
Page 110 and 111:
90toughness the material. The test
Page 112 and 113:
92From the finite element analysis,
Page 114 and 115:
94Table 4.1 Chemical Analysis of Ey
Page 116 and 117:
96Table 4.3 Tensile Coupon Test Res
Page 118 and 119:
98Table 4.5 Charpy Impact Test Resu
Page 120 and 121:
100Table 4.7 Comparison of Strain G
Page 122 and 123:
102Figure 4.1 Typical Micrograph of
Page 124 and 125:
104Figure 4.5 Fracture Surface of D
Page 126 and 127:
106Comparison of Tensile Strengthfo
Page 128 and 129:
108Combined Wrought Iron Bar Histor
Page 130 and 131:
110Figure 4.17 Macrograph of Weld u
Page 132 and 133:
112Figure 4.21 Cleavage Fracture of
Page 134 and 135:
Figure 4.25 Elongation of Hole in E
Page 136 and 137:
116signs on or near the bridge that
Page 138 and 139:
118testing of historic wrought iron
Page 140 and 141:
120so that they would act in symmet
Page 142 and 143:
122The reasons for the differences
Page 144 and 145:
124The second corrosion pattern mod
Page 146 and 147:
126Keating (1984) stated that the s
Page 148 and 149:
128charcoal fire until it is red ho
Page 150 and 151:
130Figure 5.3 Picture of Bottom Cho
Page 152 and 153:
132Figure 5.7 Using Force After Usi
Page 154 and 155:
134Figure 5.11 Reassembling a Pin C
Page 156 and 157:
1366. SUMMARY, CONCLUSIONS AND IMPL
Page 158 and 159:
138rectangular in shape. These eyeb
Page 160 and 161:
140were joined together with a full
Page 162 and 163:
1424. The Charpy impact energy of t
Page 164 and 165:
144connections are unsymmetrical, i
Page 166 and 167:
146LIST OF REFERENCESAASHTO (1998).
Page 168 and 169:
148Hodgkinson, Eaton (1840). Experi
Page 170 and 171:
150Appendix A. Data Collected From
Page 172 and 173:
152Table A.1 Wrought Iron Bar Tensi
Page 174 and 175:
154Table A.1 (continued) Wrought Ir
Page 176 and 177:
156Table A.2 (continued) Wrought Ir
Page 178 and 179:
158Table A.3 Wrought Iron Angle Ten
Page 180 and 181:
160Table A.4 (continued) Summary of
Page 182 and 183:
162Table A.4 (continued) Summary of
Page 184 and 185:
164Table A.5 (continued) Detailed I
Page 186 and 187:
Page 188 and 189:
Page 190 and 191:
Page 192 and 193:
Page 194 and 195:
Page 196 and 197:
Page 198 and 199:
Page 200 and 201:
Page 202 and 203:
Page 204 and 205:
184Table A.7 Tensile Strength Data
Page 206 and 207:
186Table B.1 Example Historic Wroug
Page 208 and 209:
188DepartmentofTransportationIf you
Page 210 and 211:
190CountyIf your organizationdoes m
Page 212 and 213:
192County 16: County bridge inspect
Page 214 and 215:
194State 13: Included in original d
Page 216 and 217:
196Figure C.1 Diagrams Showing Loca
Page 218 and 219:
198Figure C.3 Heating of Eyebar fro
Page 220 and 221:
200Figure C.7 Double V Butt Joint u
Page 222 and 223:
202Figure C. 11 Welded Tensile Coup
Page 224 and 225:
204Figure C.15 Tensile Coupon from
Page 226 and 227:
206Figure C.19 Cooling Bath with Su
Page 228 and 229:
208Figure C.23 Side View of Eyebar
Page 230 and 231:
210Figure C.27 Eyebar End Connectio
Page 232 and 233:
212Appendix D. Welding Procedure fo
Page 234 and 235:
214D.2 Filler Weld for Eyebar Conne
Page 236 and 237:
216Figure D.1 Weld Joint Detail Use
Page 238 and 239:
Figure D.5 Completed Weld Before Su
Page 240 and 241:
220Figure D.7 Initial Pass Pattern
show all

Evaluation and Repair of Wrought Iron and - Purdue e-Pubs ...

Create successful ePaper yourself

Delete template?

Save as template?