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HomeMy WebLinkAbout08/08/2023 04. Update on Trolley Bridge Analysis 1 ot `Y� ? s `'°,.,'tea BUSINESS OF THE CITY COUNCIL YAKIMA, WASHINGTON AGENDA STATEMENT Item No. 4. For Meeting of:August 8, 2023 ITEM TITLE: Update on Trolley Bridge Analysis SUBMITTED BY: Scott Schafer, Director of Public Works *Bill Preston, City Engineer, (509) 576-6754 SUMMARY EXPLANATION: The City of Yakima solicited an engineering inspection of the Yakima Valley Trolley bridge over the Naches River in April 2023. Sargent Engineering was selected to perform the following tasks on the bridge: • Performing a hands on fracture critical inspection of the bridge including all truss members both top and bottom. • Ultrasonically test bridge pins and other elements for cracking and significant flaws. • Provide a structural analysis of the South Abutment. • Prepare a report that documents current conditions and compares it to the last Fracture Critical Analysis done in 2008, including pictures. • Provide recommendations for maintenance and repairs, if needed. Sargent Engineering provided two reports; one for the south abutment and one for the remaining items. The representative from Sargent Engineering will present the City Council with findings from both reports. ITEM BUDGETED: NA STRATEGIC PRIORITY: Public Trust and Accountability APPROVED FOR SUBMITTAL BY THE CITY MANAGER RECOMMENDATION: ATTACHMENTS: Description Upload Date Type D Final Report Yakima Valley Bridge 8/4/2023 Corer Memo ❑ Trolley estimate expenses 8/4/2023 Corer Memo 2 SARGENT Sargent Engineers,Inc. 320 Ronlee Lane NW Olympia,Washington 98502-9241 Tel 360 867-9284 www sarge nteng i nee rs.com August 1, 2023 Bill Preston, PE City of Yakima Engineering 129 North Second Street Yakima, WA 98901 (509)575-6111 RE: Yakima YVT Trolley Bridge Inspection Project No.: A23125.00 Dear Mr. Preston: INTRODUCTION The Yakima Valley Transit Bridge is a three-span bridge. Span one consists of timber stringers and timber supports, and span two and three consist of a thru steel truss. The bridge is located within Yakima's city limits. The railroad bridge was constructed in 1920 and is used by the city for trolly trains. The bridge is supported by two interior concrete pier walls, one concrete abutment, and one timber abutment. The two thru-truss spans have a steel floor system comprised of transverse steel floor beams and longitudinal steel stringers. The deck consists off transverse railroad ties with timber curbs full length. SCOPE OF WORK • Perform a fracture critical inspection of the bridge. ;;;1 This includes the inspection of all the primary structural components of the bridge (truss, floor '; beams, stringers, and cross-bracing) `' lys, f`' • Conduct ultrasonic testing of each of the bridge's r d connecting pins • • Document any observed deficiencies that may c • affect the load carrying capacity of the bridge or require maintenance or repairs, • Prepare a memo documenting our findings, including any maintenance recommendations pt necessary • Prepare routine inspection report and update WSBIS xa 3 SARGENT Mr. Preston Page 2 August 1, 2023 STRUCTURAL OBSERVATIONS On June 19, 2023 Sargent Engineers observed the general condition of the bridge. The bridge members within reach using climbing techniques were visually inspected. For the purpose of this report, assume the bridge orientation to be generally South to North, with Span 1 being nearest City of Yakima. Below is a summary of our findings by member type. TIMBER DECK TIES There are 337 transverse timber railroad ties along the entire length of the bridge. The timber deck ties range from good to poor condition. Many of the deck ties have visible decay, internal tie rot, or burn damage which accounts for 36%of the total 337 timber ties. See attached images IM03 and IM04. TIMBER STRINGERS Span one consists of(6) 12"x27" treated timber stringers. Stringers 3 and 6 are moderately decayed with rot pockets up to 12"deep with approximately 1"side shells decay in stringer 1 is minor at this time. STEEL TRUSSES There are two painted steel thru-truss main spans. Overall, the paint condition of the bridge is in good condition. Minor pack rust has developed under the top cover plates both sides of bridge at U2, U5, U8 and U11. There is a small isolated delamination in the Cross brace between U3 east to U4 west. Ultrasonic testing of each of the pins resulted in the finding of an indication in the Span 2, L1 West pin. See attached image IM05 and IM06. STEEL FLOOR BEAMS There are four transverse painted steel floor beams at each truss panel point along the main spans. The steel floor beams and the paint are in good condition. Previous painted over pack rust has deformed the vertical floor beam end plates at the panel point just above the pin up to 3/4". There is no observed section loss. See attached image IM07. STEEL STRINGERS There are two longitudinal painted steel stringers spanning between floor beams. The stringers consist of built up steel plate members. The steel stringers are in good condition. The paint is in good condition with no observed signs of water intrusion. See attached image IM14 through IM15. STEEL BEARINGS There are fixed and movable bearings below the truss ends. The bearings are in good to fair condition. There is minor deformation to the roller stop plates of the East roller bearing at pier 3. Minor rusting exists where the rollers contact the bearing plate. See attached image IM08 through IM09 4 SARGENT Mr. Preston Page 3 August 1, 2023 CONCRETE PIER WALLS The interior substructure elements consist of concrete pier walls. The concrete pier walls are in fair condition. The concrete is moderately cracked with pattern cracks extending down the pier wall face. The decorative column caps are deteriorating with large spells and cracking. See attached image IM11 A large drift dam exists between Pier 3 and the southern bank. There is scour along the footing at Pier 3. Measurements were taken along the accessible edge of the footing with a maximum of 3.5'from the top of the footing to the channel bottom at the upstream end. This is a 1.5' increase since the previous inspection. See the figure below, and attached images IM12 &IM13. COBBLE/BOULDER SPUR OLD COFFER DAM 3.5' FACE 2.0' FACE 3.5' FACE 2.0' 'ACE 2.5' FACE BOULDER 2•O RIP RAP FACE 4 ! . PIER WALL FOOTING '! I DRIFT DAM BACK WATER PIER 3c1 CONCRETE ABUTMENT The abutment at the bridge north end consists of a concrete wall. The concrete abutment is in relatively good condition. There is some spelling of the decorative caps. See image IM10 5 SARGENT Mr. Preston Page 4 August 1, 2023 TIMBER ABUTMENT The south timber abutment is in poor condition as documented in the South Abutment Inspection report, included as Appendix A to this report. SUMMARY The steel thru truss is in relatively good condition. There is only minor pack rust that has developed at the previously mentioned floor beam connections. The Pier 3 pier wall footing scour has increased since the previous inspection. It is unknown how much of the foundation has scoured and may warrant continued monitoring of the foundation. The damaged/deteriorated timber ties are in poor enough condition that replacement is warranted. Span one timber stringers 3 and 6 were found to be moderately decayed with rot pockets. These decayed stringers are not believed to last long under proposed use. RECOMMENDATIONS • Replace decayed timber stringers 3&6 in Span 1 in kind • Replace the damaged/decayed timber deck ties in kind • Replace south timber abutment • Perform ultrasonic test of Pin S2-L1 West • Monitor Pier 3 foundation for scour • Brush back vegetation growing into Span 2 Truss Attached are observation photos and a rough order of magnitude estimate to assist in planning for the completion of the above recommendations. The estimate incorporates costs associated with the south timber abutment replacement recommended in the South Abutment Inspection report. Thank you for this opportunity to assist you with this project, if you should have any questions, please do not hesitate to call. Respectfully, Ad Sargent Engineers, Inc. � PoRO WAS H,N -0 51096 Craig Mallow, PE 10 �ec�sTER` `� Senior Project Engineer SS/ONAL \ ./3/23 qgc, Encl. B:\23Files\W23125.00 YVT Bridge Inspection\Reports\Report_Yakima Valley Bridge.docx 6 SARGENT Mr. Preston Page 5 August 1, 2023 ,. yY>'- h e*•'' �Y'•' 'r ,l't :: •' 1 f Lit pp �, i ITRESP si GI 3tt Y r :r3Y. —i , _ _ rf7*;. M - -.�\� 14,i. k, 5%Ai_.- ''f ram--s' V ` rii jam„„„ `1 �`l��Mir x--66 * . _` / �, - f �i.v f 4 ` c ( w � F .5" • - - w ."' { - ` .' -" : ti ' :', ..-:116'. r _" , . IM01 —Elevation looking Southeast IM02—Elevation Through Truss -° r ...• _ x� r. 411114440444 K._ , I M03—Charred Timber Deck I M04—Decayed Deck Timber Vfj,,,s., ' ' :' r. ,,,- ,.. , _.......,,,,,..„,, A. a s /. _,_.,_. .._ ,,, F. _.....,„ ,. ., . ti • , .._, ,..... ..,,,..„, ....,..„...„a 4, r., ::7:3".L.:4.!,..::::0.:. •.- \ r xnY ` ` .• ` ,`'•.giro ...„ y • 4 r t� 4 IM05—Pack Rust Under Top Plate IM06—Delam in U3 East, U4 West Cross Brace 7 SARGEIIT Mr. Preston Page 6 August 1, 2023 ., ii A _ , • ) %, psi )'/" / s b — 4. , tw (,.......-:';-:::r...-....11" i ' ' !}ate' IM07—Typ. Pack Rust at Floor Beam Pannel Point IM08—Typ. Roller Bearing I a. 4* _. � F �'' �r..^ , - ems. ,. :� -.. "'o .. 7'*:.; r,s -,Cr .k- * •` fit r r R IM09—Typ. Fixed Bearing IM10—Concrete Abutment(A4) ,3 r.ti. A7 n4�400:P/:. 1 .„. ....6 :N,"' 1E, 5 i IM11 —Pier 3 Erosion Looking West IM12—Drift Dam Between Pier 3 and South Bank 8 SARGENT Mr. Preston Page 7 August 1, 2023 11ilt.4.40 'j:, ,I a', , y • �� i :p'69 v i� I dl �'x ♦ VIA' `I „ / I ', t 1� Illi . .:.Jn J.yr wr Image 13—Typ. Cracking/Spalling in Pier Wall Image 14—Typ. Stringer and Floor Beam Condition or \ , 4,,,i..,,r ...: ,,,. .,,, /N )1,0,,,,'1 4 ';. ,y.,,,',.. ,`," '4, _ _- .�Wy� 3- . .4f4 '..,.\ r" p, ., `l l ., e, a' x cI fir- n , ;�' . �. '- / —-- " a _— A ..,1_ n '' M Image 15—General Construction from Below Image 16—Foliage in Span 2 Looking North i '_ Tim I. {l+ t s_ ka . : . is ,hi Image 17—Pier 2A and Pier 2B Image 18—Under Span 1 Looking at Abt 1 9 SARGENT Mr. Preston Page 8 August 1, 2023 ROUGH ORDER OF MAGNITUDE CITY OF YAKIMA WT TROLLEY BRIDGE ROM COST ESTIMATE ITEM DESCRIPTION UNIT QTY UNIT COST COSTS Remove and Replace Timber Stringers 1 L.S. $ 40,000 $ 40,000 Remove and Replace Timber Ties 1 L.S. $ 35,000 $ 35,000 Replace South Timber Abutment 1 L.S. $ 104,500 $ 104,500 Ultrasonic Pin Inspection 1 L.S. $ 10,000 $ 10,000 Clear Brush 1 L.S. $ 3,000 $ 3,000 Subtotal = $ 192,500 PE Costs (25%) EST. 1 ---- $ 48,125 Right of Way Costs EST. 0 ---- $ - Construction Engineering (18%) EST. 1 ---- $ 34,650 Contingency (15%) EST. 1 ---- $ 28,875 Mobilization (10%) L.S. 1 ---- $ 19,250 Inflation Factor(5% per year) YEAR 1 ---- $ 9,625 Total Costs for Rehablitation $ 333,025 10 5j'tJ)%GEIJF Mr. Preston Page 9 August 1, 2023 APPENDIX A 11 SARGENT Sargent Engineers,Inc. 320 Ronlee Lane NW Olympia,Washington 98502-9241 Tel 360 867-9284 www sa rgenteng i nee rs.com June 17, 2023 Mr. Bill Preston, PE City of Yakima 129 North Second Street Yakima, WA 98901 RE: Yakima YVT Trolley Bridge—South Abutment Inspection Project No.: A23125.00 Dear Mr. Preston: On May 2, 2023, Craig Mallow and Chet Kocan of Sargent Engineers, Inc. made a site visit to inspect the abutment deterioration on the Yakima Valley Trolley Bridge over the Naches River. The structure is 324 foot long carrying a single-track railway in a generally south to north direction from the north end of Yakima, Washington toward Selah, Washington. The three spans are a 26-foot-long timber girder span and two 149-foot steel through truss spans. The deteriorated south timber abutment supports one end of the 26-ft timber girder span. OBSERVATIONS The following observations are for the south timber abutment. The timber foundation is comprised of individual 8x12 timber sill footings. The foundation supports a 12x14 transverse timber cap. The cap supports the superstructure which is comprised of (6) 12x27 longitudinal timber girders and 8x12 timber deck ties spaced 18" on center. The backwall retaining the approach fill is comprised of 6x16 timber lagging stacked (3)high. 8x12x10—ft © 18"o.c. Timber Deck Ties, typ. 6x16 Timber—\1/4 1l X 17 47 1l X Lagging, typ. 12x27 Timber I XX / 12x14x15ft 01 Girders, typ. [4. Cap J<ma<<I C mm<I«I� ±8x12 Timber Sill Foundation1.1 • The first timber tie behind the timber lagging has settled resulting in an approximate 3" gap between the rail track and the tie. • The timber sill footings are severely decayed and crushed. There was no need to sound or drill the sills to determine the extent of remaining material. They are in a failed state. (Image next page) • The timber lagging back wall is moderately to severely decayed. While sounding with a hammer, the backwall was punctured to decay. Currently, the backwall is still functioning as fill retention, but due to decay, there is little remaining service life. (Image next page) • The timber cap was sounded using a geologist's hammer to locate any possible decay. No signs of decay were observed. 12 Elil Yakima YVT Trolley Bridge South Abutment Inspection Page 2 PHOTO DOCUMENTATION \ -.� � A Settled Approach Tie f 3 " I t 4i' - .. � ,� Fn� a .t 'd:�Yt`'=, m...�--. - Severely Decayed -, Decay Hole in Timber Sill Footings Timber Lagging CONCLUSION The timber sill footings have failed and the timber backwall is moderately to severely decayed. If trolley traffic were allowed to cross the bridge in this condition, there is significant risk that the abutment will collapse under the trolley's weight. The timber sill footings are approximately 8-inches thick and would initiate the collapse by crushing, causing the timber girders and rails to abruptly sink and possibly tilt,which could cause the trolley to derail. Given the failed condition state of the sill footings, there is no reliable strength remaining to support the superstructure. Guidance provided within the WSDOT Bridge Inspection Manual states"bridges not capable of carrying a minimum gross live load of three tons shall be closed." As such, due to the observed failed condition state, potential for collapse under trolley loads, and guidance provided by the governing inspection agency, we recommend closing the bridge to trolley traffic until repairs are made. Repairs can be completed by temporarily shoring the existing timber girders, removing the decayed timber elements, and replacing them with a new foundation and backwall. Once the foundation elements are replaced, regrading and compacting the approach fills will be required. To improve maintenance and service life,we recommend replacing the timber sill footings with a reinforced concrete footing and the timber backwall with a reinforced concrete or corrugated steel backwall. We estimate a rough order of magnitude of$115,000 plus permitting and engineering to complete this work. Please contact us with any comments or questions or if you need additional services such as assembling repair plans and specifications. Sincerely, F �tRON ,, Sargent Engineers, Inc. � PoF wasi.//47 "T 4". It -0 0 ct Craig Mallow, P.E. -0 51096 Senior Project Engineer �(" s c/sT E �"<v ("Is \ /i-7/23 CAM B:123Files1A23125.00 YVT Bridge I nspection\AbutmentReport.docx Trolley expenses 13 2023 Operation/Maintenance $ 10,000 Inspection $ 25,000 From Snow& Ice Fruitvale track repair $ 35,000 Includes$11k for ties State grant $ (25,000) Total $ 45,000 Future Pier 1 Abutment $ 115,000 prior to opening Remaining maintenance $ 152,240 Total $ 267,240 We do not have a budget or revenue forcast from YVT