Preliminary Design Report, Wilburton Trestle - East Rail ... · Wilburton Trestle – East Rail Corridor Bridge No. SA-9 Preliminary Design Report (DRAFT) Department of Natural Resources

Wilburton Trestle – East Rail Corridor Bridge No. SA-9 Preliminary Design Report (DRAFT)

Department of Natural Resources and Parks Parks and Recreation Division Capital Planning and Land Management Section King Street Center 201 South Jackson St., Suite 700 Seattle, WA 98104-3856 December 23, 2015

Table of Contents

W i l b u r t o n T r e s t l e ( B r i d g e S A - 9 ) P r e l i m i n a r y D e s i g n R e p o r t 1

Introduction ................................................................................................................................................... 2

Project Background .............................................................................................................................. 2

Bridge Description ........................................................................................................................................ 3

Year of Construction and Previous Repairs ..................................................................................... 3

Bridge Inspection........................................................................................................................................... 4

Structural Analysis ......................................................................................................................................... 5

Load Rating Vehicles ........................................................................................................................... 5

Methods and Assumptions ................................................................................................................. 6

Results and Recommendations .................................................................................................................... 7

Trail Width and Decking Options ..................................................................................................... 8

Timber Stringers ................................................................................................................................... 9

High Level Caps ................................................................................................................................ 10

Posts and Piles ................................................................................................................................... 10

Mid- and Low- Level Caps ............................................................................................................... 12

Foundation Piles ................................................................................................................................ 12

Lateral Bracing ................................................................................................................................... 12

Steel Girders ....................................................................................................................................... 13

Repair Cost and Constructability ............................................................................................................. 13

Equipment and Access ..................................................................................................................... 13

Concrete Deck, Stringers, and High Level Cap Replacement .................................................... 13

Posts ................................................................................................................................................ 14

Mid- Level Caps ................................................................................................................................. 14

Piles ...................................................................................................................................................... 14

Lateral Bracing ................................................................................................................................... 14

Additional Member Replacement ............................................................................................................ 15

Continued Monitoring ............................................................................................................................... 15

Full Bridge Replacement ........................................................................................................................... 15

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Bridge Description The trestle consists of 60 timber trestle spans and one steel girder span with a total length of approximately 975 feet. The timber trestle spans are supported on driven timber pilings. The steel girder span is supported on tall concrete piers. The trestle crosses over SE 9th Street, Richards Creek, and SE 8th Street. The south end of the bridge has a slight horizontal curve through about Bent 9 with a straight alignment beyond. The bridge deck is roughly 100 feet above ground at its maximum height. Year of Construction and Previous Repairs Based on the HAER report referenced above, The bridge was originally constructed in 1904 and completely rebuilt in 1913, 1924, 1933, and most recently in 1944. The concrete piers and steel girders were installed in 1972. All timber is assumed to be fir based on information in the HAER report. Numerous piles have been repaired with what appears to be a patching compound. A timber cover piece is placed over the patch and secured with metal banding. The age of these repairs is not known. We are referring to these types of repairs below as banded patch repairs. It also appears numerous members have received a fumigant or other internal treatment. We observed plugged access ports for the treatment and metal ID markers indicated Osmose treatment. Bents 1 – 11: These bents consist of six driven timber piles that are full height extending up to the deck level. The piles have lateral and longitudinal timber bracing in the horizontal and diagonal directions along their height, creating a frame with several levels. The pile diameter increases from the ground level up. Sizes averaged 12” at the bottom and roughly 22” at the top. All timber is creosote treated. Bents 12 and 13: These two bents are unique and consist of seven timber piles, continuous up to the deck level, that are slanted in the longitudinal direction in order to make room for SE 9th Street at the base while maintaining desirable span lengths for the stringers at the top. Timber framework spans between these two bents to provide stability for the slanted piles. Unlike the longitudinal bracing members in other spans, these are considered as primary load members. Lateral bracing between the piles is also present. All timber is creosote treated. Bents 14 – 35: These bents are similar to Bents 1 – 11. At the time of our inspection, the piles at Bents 20-31 were submerged in approximately 12 inches of water. Bents 35 – 46: These bents consist of six driven timber piles that extend several feet above ground. On top of the piles are six square timber posts with caps and framing above. The square piles are discontinuous between levels with a timber cap beam between levels. The posts are braced to one another with


lateral and longitudinal bracing members. The drive piles are creosote treated, however, the square posts and framing likely were treated with Wolman salts based on the HAER report. Wolman salts are a wood preservative treatment used in the early and middle part of last century but do not appear prevalent in newer construction. Bent 47: The foundation for this bent consists of driven steel H-piles with steel framing supporting six square timber posts with caps and framing above. Bents 48 and 51: These are short timber pony bents with five square posts that sit on top of the tall concrete piers and support the end of the timber stringer span just prior to and after the steel girder span. Bents 49 and 50: These bents are the tall concrete piers that support the steel girder span. Bent 52, 53, and 54: These bents have steel piles and framework at the base supporting 5 square posts with caps and framing above. The timber framing on top of the steel assembly is not creosote treated and likely treated with Wolman salts. Bents 55 – 60: These bents have five driven piles that support five square posts with caps and framing above. The timber framing on top of the steel assembly is not creosote treated and likely treated with Wolman salts. Bents 61 - 64: Bents 61 - 64 are circular continuous piles with the top pile cap extending beyond the superstructure. These bents have old, relic piles from previous portions of the bridge. Many of them show severe defects but are not considered to be a load carrying portion of the structure. Superstructure The existing superstructure consists of steel rails and 8”x8”x10’-0” long timber cross ties supported on timber stringers or steel girders. The timber stringers are 9x17 solid sawn lumber. Twenty one of the 60 spans have 8 stringers total while the rest have 6. The steel girders are plate girders with both riveted and bolted connections. The girders are 8 feet deep and spaced 8 feet apart.

Bridge Inspection We conducted a bridge inspection for the purpose of obtaining and confirming sufficient information to perform a structural assessment of the bridge in its current condition and for future trail amenities. The inspection report was prepared as a stand-alone document and is not included with this report.

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Methods and Assumptions Additional methods and assumptions are as follows:

1) Timber members were load rated per allowable stress design methods (ASD) and the steel girders per the Load and Resistance Factor Rating (LRFR) method according to the following specifications:

a. AASHTO Manual for Bridge Evaluation 2nd Edition, 2011 (AASHTO MBE) b. AASHTO Standard Specifications for Highway Bridges, 17th Edition (AASHTO

SSHB) c. WSDOT Bridge Design Manual (WSDOT BDM)

2) For timber members, Inventory Level allowable stresses were used for the AASHTO design vehicles and Operating Level (33% higher allowable than Inventory) for the King County maintenance vehicles.

a. We believe the Operating Level is prudent for the maintenance vehicles because the specific weights and spacings are known and the frequency of these heavy loads will be relatively low over the lifespan of the bridge.

3) The structural analysis considered vertical loads only which included self weight of the bridge members and the weight of the vehicles being applied. The load rating did not consider seismic, wind, or lateral loads.

4) No live load impact was applied to the timber members. For the steel girders, an impact factor of 10% was added to the King County live loads and 33% for the AASHTO design vehicles.

5) The pile end conditions are pinned and a braced frame effective length factor, K, of 1.0 applies.

6) Timber deterioration was accounted for by adjusting the section properties of the section. The cross sectional area and section modulus were reduced based on the estimated dimension if internal decay.

7) Material properties were determined based on guidance provided in AASHTO MBE and WSDOT BDM and were taken as follows: Timber (AASHTO SSHB Table 13.5.1A)– Douglas Fir #1 for stringers and Douglas Fir Select Structural for all other timber (WSDOT BMD 13.2.14 – “Unless the species and grade is known, assume Douglas fir. Use select structural for members installed prior to 1955 and No. 1 after 1955. The allowable stresses for beams and stringers shall be as listed in the AASHTO Specifications.”)

a. Allowable bending stress in timber stringers, Fb = 1,350 psi b. Allowable bending stress in timber posts and caps, Fb = 1,200 psi c. Allowable shear stress in all members, Fv = 85 psi d. Allowable compression parallel to grain in timber posts, Fc = 1,000 psi e. Allowable compression perpendicular to grain in timber posts and caps, Fpc = 625

psi f. Wet Service Factors, CM = 1.0 for shear and bending, 0.91 for compression, 0.67 for

bearing


g. Load Duration Factors, CD = 1.15 all loadings except compression perpendicular to grain

h. Shear Stress Factor, CH = 1.0 for timber stringers (conservative assumption to account for uncertainty in aging wood structure and difficult inspection access)

i. Allowable stress values are to be modified by additional modification factors such as size factor and beam stability factor, see load rating

Steel (AASHTO MBE Table 6A.6.2.1)– Douglas Fir #1 for stringers and Douglas Fir Select Structural for all other timber (WSDOT BMD 13.2.14 – “Unless the species and grade is known, assume Douglas fir. Use select structural for members installed prior to 1955 and No. 1 after 1955. The allowable stresses for beams and stringers shall be as listed in the AASHTO Specifications.”)

a. Structural steel yield strength, Fy = 36 ksi (steel built after 1963, AASHTO MBE 6A.6.2.1)

b. Condition factor, c = 1.00 (Structural condition good or satisfactory, AASHTO MBE 6A.4.2.3-1)

c. System factor for flexure and axial effects, s = 0.90 (Riveted members in two-girder bridges, AASHTO MBE 6A.4.2.4-1)

.

Results and Recommendations Based upon the results of the load rating and observations made during inspection, we recommend repairing or replacing certain bridge components in order to utilize the bridge for maintenance vehicle and pedestrian access. We are recommending repair or replacement when:

Any member has a RF less than one; The member has defects or deterioration to an extent that we believe will limit its remaining

lifespan, even if the member currently has sufficient load carrying capacity. The overall level of repair for the bridge will depend on which maintenance vehicles will be allowed to use the bridge, the desired lifespan of the structure, the desired decking type and width, and the construction budget. We are presenting repair options for the following three vehicle groups, each with three different lifespans and two decking options –

Group 1 – King County truck and trailer with 75,000 lb. excavator, AASHTO HS20 design highway load;

Group 2 – King County 10-yard dumptruck; Group 3 – AASHTO H10 and 90 psf pedestrian bridge design live loads.

In addition, we have evaluated repair requirements for the following approximate lifespans –

Up to 25 years

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than 1.0, but numerous stringers with moderate levels of decay and above has RF’s < 1 for one or more of the vehicles. The total number of replaced stringers depends on which vehicle group and decking configuration the County chooses. Our estimate assumes re-use of existing stringers where possible except for the 50-year lifespan, where we assumed full replacement of all of the stringers. If all stringers are replaced, glu-laminated stringers can be used to reduce the overall number of stringers. These options are summarized in the following table:

Vehicle Group # Vehicles Deck Width Minimum No. of

Solid Sawn Stringers Minimum No. of Glu‐Lam Stringers

1 Truck + Trailer with 75,000 Lb. Excavator,

AASHTO HS20

14 7 5

12 6 4

2 Loaded 10‐yard dumptruck

14 6 4

12 5 4

3 AASHTO H10,

AASHTO Pedestrian Load

14 5 4

12 5 4

High Level Caps The high level caps typically consist of two 8-inch wide by 15-inch deep members placed side by side. This configuration was likely used to provide increased bearing width for the piles at the top since the pile diameters here are greater than 12 inches. Numerous caps are being recommended for replacement due to observed levels of deterioration. The replaced pile cap will be similar dimensions as existing. Posts and Piles Posts are discontinuous members between cap beams while piles are the foundation components of the bridge and more numerous bents are full-height members extending to the top cap. Posts and piles were analyzed for compression parallel to grain and end bearing. The area of decay was deducted from the load bearing area when calculating capacity. The maximum unbraced length of the post was taken as the distance from the cap to the mid-height brace, approximately 10-15 feet. Looking northwest, the posts are labeled A, B, C, D,… from left to right. In our analysis, we distributed loads equally to each pile. In our experience, it is infrequent that piles load rate below 1.0 for compression, except for cases where piles have severe rot. The redundant nature of trestles and the compressive strength of timber typically result is adequate load carrying capacity.

Photo 1: Stringer group and high level cap

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Our replacement recommendations and cost estimate are based on lifespan estimates. Mid- and Low- Level Caps Mid- and low-level caps consist of double 12x12” members at Bents 35-47 and 52-60. The posts are sufficiently aligned above one another so that minimal to no shear or bending moments are produced. Based on our inspection and analysis, we recommend replacing several caps due to observed deterioration and in some cases, crushing beneath a portion of the post. While bearing capacity appears to be sufficient, replacement should be done to meet the desired lifespan of the bridge. Foundation Piles Foundation piles are the pile portion extending up from the ground to the lowest cap or main horizontal brace. Pile diameters at the ground level were primarily in the 12-inch range. Several bents had submerged foundation piles at the time of our inspection. We checked the piles at the water surface elevation and just below, and up to the low cap.

We observed moderate or advanced rot in several piles at Bents 10, 12, 22, 25, 28, 30, 31, 32, 33, 38, and 43. Even with this rot, our analysis indicates that the piles have sufficient capacity for all vehicle groups. Our visual observations during inspection did not reveal any existing scour around the piles at Bent 41 within Richards Creek. It is unclear whether the creek channel has migrated horizontally during the lifespan of the bridge and how long the piles have been exposed to the stream. This will be an item for future monitoring, which is discussed further below.

Lateral Bracing Lateral bracing members are considered secondary structural members but are critical to provide bracing for the posts and load distribution from lateral loads. These members were typically 2.75” x 9” for the lateral bracing members and 4 x 12 or 6 x 12 for the longitudinal bracing members. Our load rating assumes that all braces are connected and capable of providing lateral restraint to the posts. We sounded each bracing member to check for internal decay where accessible and visually inspected each member. We paid particular attention to the end condition of the brace to check for end grain rot or end splitting. We observed numerous members will end grain rot or split ends and recommend replacing the entire length of brace with this condition. Braces with split ends were prevalent especially at Bents 35-47 and 52-60. These timbers were originally treated with Wolman salts as opposed to creosote like the other timbers.

Photo 2: Foundation piles (partially submerged)

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ill likely ered for posts for e crosses uld be contract

nstruction


This work will be fairly straightforward due to ease of access from the deck. If concrete planks are proposed, the weight of the plank versus capacity of the crane will need to be verified. This work will involve removing and replacing concrete planks, or timbers and asphalt, rails, stringers, and high level caps as well as disassembling and reassembling lateral braces. Equipment and personnel will access this work from the bridge deck. Each stringer to be replaced is roughly 15.5 feet long and is supported by two trestle bents. The high level caps will be replaced concurrently with the stringers and it is also likely that the contractor will elect to perform all the work on one trestle at a time. If this is done, some disassembly and re-assembly time for the stringers and decking will be shared with the repairs on the lower portions of the trestle. Posts Our costs assume that deteriorated posts will be fully replaced. Installing a splice appears to be present a slight cost savings, but we believe the value of having a new post outweighs the cost savings. Work access and shoring installation represent the bulk of the cost for post repair. Disassembling and re-assembling lateral bracing will require additional time. Based on our experience, the contractor will prefer to shore off of the ground or that is not possible that may shore off of the cap level below. Shoring is necessary to release the load off of the member to be replaced. Mid- Level Caps We anticipate that access to these members will be similar to that of the posts with material, personnel, and tools being lowered from the deck level. We recommend fully replacing the caps rather than partial replacement due to significant deterioration along their length. Each post will have to be temporarily supported during cap replacement, and therefore the shoring system will be more expensive and time consuming than for posts. Friction collars will likely be employed for this temporary support where numerous posts need to be lifted off of the cap for replacement. Piles Pile repair will consist of removing only the length of exposed decayed pile above ground and splicing on a new section. We are not proposing to drive any new piles. The cap beam, along with posts above, that bears on the pile will need to be temporarily shored. This work may have to be done in wet conditions and it should be anticipated that small cofferdams will be installed around the piles to dewater to ground level. Lateral Bracing Replacing lateral braces will require disassembly of the existing brace and lowering new material from the deck. The braces will be lighter and easier to handle than the posts or mid-level caps. Lateral bracing members could be accessed from either the deck or the ground, depending on where the braces are located. We anticipate minimal temporary shoring, if any when replacing lateral braces.


The construction documents should include a construction sequence and approach information that clearly defines the limitations that the contractor must follow. This should include, at a minimum, maximum construction loads on the deck, sequencing requirements, and the submittal requirements for a demolition and construction plan to be prepared by the contractor’s engineer.

Additional Member Replacement During construction of the trestle repair, each member that is detached and re-installed, or exposed during detachment of adjacent members, should be inspected by a qualified inspector to check for decay or deterioration not previously found. Given the age of the bridge and number of bridge components, it is possible that members in addition to those specified in the contract quantities, will need to be replaced. The contractor can be compensated for this work in a number of ways – per unit price if the quantity does not exceed 25% of original contract quantity, by negotiated unit price, by force account, or by having the contractor purchase additional materials at the beginning of the work. Larger treated timber material typically has a long lead time. We recommend including in the contract extra material for the contractor to furnish and have on hand. Having this on hand will avoid delays in construction if additional material needs to be ordered. The contract should have language that defines how the contractor will be paid if this material is then installed due to unforeseen condition.

Continued Monitoring Due to the nature of timber structures exposed to the environment, decay will continue to occur regardless of the level of rehabilitation done. Existing members without observed rot, or with minor levels of rot, could have a remaining service life in the 25-year range but beyond that it is less predictable. Inspection of both newly installed members and existing members should continue to occur at regular intervals established by King County.

Full Bridge Replacement Full replacement of the bridge was not part of the scope of work nor was it discussed with the King County. Wilburton Trestle is a historic structure and preservation is the preferred option. If the County desires, a comparison of the lifespan of a new bridge, which is on the order of 75 years, and its associated cost could be done against the lifespan of the selected repair alternative and its associated cost. Appendix A contains an alternatives matrix, the estimated cost breakdown, and the repair summaries. Concept-level typical deck sections and trestle bent elevations with repairs of various substructure components.

Appendix A – Cost Estimates and Proposed Details

Alternatives Matrix Wilbutron Trestle Rehabilitation Cost Estimate

Bridge # SA‐912/23/2015 King County Department of Natural Resources and Parks

The following are the alternativs we considered:

Vehicle Groups

Group 1Truck + Trailer with 75,000 Lb.

Excavator, AASHTO HS20

Group 2 Loaded 10‐yard dumptruck

Group 3AASHTO H10, AASHTO Pedestrian

Load

Lifespan Options

Up to 25 years

Up to 35 years

Up to 50 years

Deck Type Options

Concrete deck

Asphalt wearing surface

Deck Width Options

12 feet

14 feet

STRUCTURE COST ITEMS ‐ ALL VEHICLES

Vehicle Group Vehicle Use Estimated Life SpanEstimated Construction Cost ‐

14' Concrete Deck

Estimated Construction Cost ‐

12' Concrete Deck


14' Asphalt Deck


12' Asphalt Deck

Up to 25 years 4,874,925$ 4,481,950$ 4,310,488$ 3,998,225$

1Truck + Trailer with 75,000 Lb.

Excavator, AASHTO HS20Up to 35 years 6,661,875$ 6,268,900$ 6,097,438$ 5,785,175$

Up to 50 years 8,085,963$ 7,692,988$ 7,521,525$ 7,209,263$

Up to 25 years 4,724,638$ 4,290,138$ 4,160,200$ 3,806,413$

2 Loaded 10‐yard dumptruck Up to 35 years 6,470,063$ 6,077,088$ 5,905,625$ 5,593,363$

Up to 50 years 7,894,150$ 7,692,988$ 7,329,713$ 7,209,263$

Up to 25 years 4,702,225$ 4,290,138$ 4,137,788$ 3,806,413$

3AASHTO H10, AASHTO Pedestrian

LoadUp to 35 years 6,278,250$ 6,077,088$ 5,713,813$ 5,593,363$

Up to 50 years 7,894,150$ 7,692,988$ 7,329,713$ 7,209,263$

K:\project\32400\32499A\Structures\Cost Estimate\RepairSummary&Costs.xlsx 12/23/2015

Repair Cost Estimate Tabulation Wilbutron Trestle Rehabilitation Cost Estimate

Bridge # SA‐9

12/23/2015 King County Department of Natural Resources and Parks

STRUCTURE COST ITEMS ‐ ALL VEHICLES

Item Unit Quantity Unit Cost Total Quantity Unit Cost Total Quantity Unit Cost Total

TESC LS 1 45,000$ 45,000$ 1 55,000$ 55,000$ 1 65,000$ 65,000$

SPCC LS 1 5,000$ 5,000$ 1 5,000$ 5,000$ 1 5,000$ 5,000$

Construction Survey LS 1 8,000$ 8,000$ 1 10,000$ 10,000$ 1 12,000$ 12,000$

Restoration LS 1 6,000$ 6,000$ 1 8,000$ 8,000$ 1 10,000$ 10,000$

Bridge Railing LF 1950 165$ 321,800$ 1950 165$ 321,800$ 1950 165$ 321,800$

High Level Cap Replacement EA 16 5,000$ 80,000$ 33 5,000$ 165,000$ 40 5,000$ 200,000$

Mid‐Level Cap Replacement EA 10 20,000$ 200,000$ 12 20,000$ 240,000$ 25 20,000$ 500,000$

Post Replacement EA 10 14,000$ 140,000$ 20 12,500$ 250,000$ 30 11,000$ 330,000$

Pile Splice EA 44 16,000$ 704,000$ 74 14,500$ 1,071,300$ 116 13,000$ 1,507,000$

Lateral Bracing LF 2179 85$ 185,300$ 4340 80$ 347,200$ 5132 75$ 384,900$

Longitudinal Bracing LF 1370 95$ 130,200$ 2536 90$ 228,300$ 3010 85$ 255,900$

Steel Girder Painting LS 1 250,000$ 250,000$ 1 250,000$ 250,000$ 1 250,000$ 250,000$

Extra Material On Hand and Installation (10%) LS 1 143,950$ 144,000$ 1 230,180$ 230,200$ 1 317,780$ 317,800$

SUBTOTAL 2,219,300$ 3,181,800$ 4,159,400$

DECKING COSTS ‐ ALL VEHICLES


Concrete Deck (12' Wide Trail) SF 11700 75$ 877,500$ 11700 75$ 877,500$ 11700 75$ 877,500$

Asphalt Deck (12' Wide Trail) SF 11700 45$ 525,700$ 11700 45$ 525,700$ 11700 45$ 525,700$

Concrete Deck (14' Wide Trail) SF 13650 75$ 1,023,800$ 13650 75$ 1,023,800$ 13650 75$ 1,023,800$

Asphalt Deck (14' Wide Trail) SF 13650 45$ 613,300$ 13650 45$ 613,300$ 13650 45$ 613,300$

STRINGER COSTS ‐ GROUP 1 VEHICLES


Stringer Replacement (12' Wide Trail) LF 1085 150$ 162,800$ 3333 150$ 499,900$ 3720 150$ 558,000$





Stringer Replacement (14' Wide Trail) LF 1287 150$ 193,000$ 3333 150$ 499,900$ 3,720.00 150$ 558,000$



Stringer Replacement (12 foot trail) LF 155 150$ 23,300$ 2403 150$ 360,400$ 3720 150$ 558,000$

Stringer Replacement (14 foot trail) LF 1178 150$ 176,700$ 2403 150$ 360,400$ 3,720.00 150$ 558,000$

Up to 50 years

Up to 25 years

Up to 25 years Up to 35 years Up to 50 years


Up to 35 years Up to 50 years


Up to 25 years Up to 35 years


Repair Cost Estimate Tabulation Wilbutron Trestle Rehabilitation Cost Estimate

Bridge # SA‐9


TOTAL CONSTRUCTION COST PER VEHICLE GROUP AND DECKING OPTION

Addition Project Costs Include:

Mobilization 10%Contingency 25%

Lifespan14' Wide Trail ‐

Concrete

12' Wide Trail ‐

Concrete

14' Wide Trail ‐

Asphalt

12' Wide Trail ‐

Asphalt

Up to 25 years 4,874,925$ 4,481,950$ 4,310,488$ 3,998,225$

Up to 35 years 6,661,875$ 6,268,900$ 6,097,438$ 5,785,175$

Up to 50 years 8,085,963$ 7,692,988$ 7,521,525$ 7,209,263$

Up to 25 years 4,724,638$ 4,290,138$ 4,160,200$ 3,806,413$

Up to 35 years 6,470,063$ 6,077,088$ 5,905,625$ 5,593,363$

Up to 50 years 7,894,150$ 7,692,988$ 7,329,713$ 7,209,263$

Up to 25 years 4,702,225$ 4,290,138$ 4,137,788$ 3,806,413$

Up to 35 years 6,278,250$ 6,077,088$ 5,713,813$ 5,593,363$

Up to 50 years 7,894,150$ 7,692,988$ 7,329,713$ 7,209,263$

Construction Cost Notes:Costs are in present day dollarsCosts do not include any utility relocationsCosts do not include final engineering or construction administration

Group 1 Vehicles

Group 2 Vehicles

Group 3 Vehicles


Stringer Repair Summary and Unit Cost Wilbutron Trestle Rehabilitation Cost Estimate

Bridge # SA‐9


Assumptions:

Replace all stringers with observed defect

Lifespan of new stringer 50 years

Remaining lifespan of existing stringer with no observed defect 25 years

Input:

Total number of stringers 396

Total number of stringer spans 60

Number of stringers with defect observed 106

Number of stringers with severe deterioration observed 13

Number of stringers with advanced deterioration observed 7

Number of stringers with moderate or minor deterioration observed 54

Number of stringers with other form of defect observed 32

Total number of auxilary stringers 42

Number of auxilary stringers with defect 8

Required Stringer Configuration for Different Options

Vehicle Group # Vehicles Deck WidthMinimum No. of Solid

Sawn Stringers

Minimum No. of Glu‐Lam

Stringers

14 7 5

12 6 4

14 6 4

12 5 4

14 5 4

12 5 4

1

Truck + Trailer with

75,000 Lb. Excavator,

AASHTO HS20

2Loaded 10‐yard

dumptruck

3AASHTO H10, AASHTO

Pedestrian Load



Bridge # SA‐9


Removal and Replacement Quantities for Different Options

Vehicle Group # Vehicles LifespanNo. of Existing Stringers to

be Removed

No. of New Stringers to be

Installed

No. of Existing Stringers to

be Removed

No. of New Stringers to be

Installed

Up to 25 years 106 130 106 70

Up to 35 years 251 275 251 215

Up to 50 years 396 300 396 240

Up to 25 years 106 83 106 10

Up to 35 years 251 215 251 155

Up to 50 years 396 240 396 240

Up to 25 years 106 76 106 10

Up to 35 years 251 155 251 155

Up to 50 years 396 240 396 240

12 foot wide deck

Replace all stringers

Replace stringers with observed defect plus half of remaining

Replace only stringers with observed defect





3AASHTO H10, AASHTO

Pedestrian Load

14 foot wide deck

1



AASHTO HS20



2Loaded 10‐yard

dumptruck

Recommendation



Bridge # SA‐9


Vehicle Group # Vehicles Lifespan Disposal Quantity Disposal Total Cost Stringer Quantity Stringer Total Cost Disposal Quantity Disposal Total Cost Stringer Quantity Stringer Total Cost

Up to 25 years 39 10,801.44$ 2015 403,000.00$ 39 10,801.44$ 1085 217,000.00$

Up to 35 years 93 25,577.00$ 4263 852,500.00$ 93 25,577.00$ 3333 666,500.00$

Up to 50 years 147 40,352.55$ 4650 930,000.00$ 147 40,352.55$ 3720 744,000.00$

Up to 25 years 39 10,801.44$ 1287 257,300.00$ 39 10,801.44$ 155 31,000.00$

Up to 35 years 93 25,577.00$ 3333 666,500.00$ 93 25,577.00$ 2403 480,500.00$

Up to 50 years 147 40,352.55$ 3720 744,000.00$ 147 40,352.55$ 3720 744,000.00$

Up to 25 years 39 10,801.44$ 1178 235,600.00$ 39 10,801.44$ 155 31,000.00$

Up to 35 years 93 25,577.00$ 2403 480,500.00$ 93 25,577.00$ 2403 480,500.00$

Up to 50 years 147 40,352.55$ 3720 744,000.00$ 147 40,352.55$ 3720 744,000.00$

Unit Costs

DISPOSAL OF CREOSOTE TREATED TIMBERS

Unit Costs

Disposal of Creosote Treated TON 275.00$ Unit costs from Tokul Creek Trestle Bid Tab

Stringer LF 200 Unit costs from Tokul Creek Trestle Bid Tab

TIMBER STRINGERS

Unit Costs

Stringer LF 150.00$

Stringer LF 250.00$ Tokul Creek Trestle Bid Tab

Stringer LF Supplier provided delivered cost, estimate labor cost

14 foot wide deck 12 foot wide deck

1

2

3



AASHTO HS20

Loaded 10‐yard

dumptruck

AASHTO H10, AASHTO

Pedestrian Load


Post and Pile Repair Summary and Unit Cost Wilbutron Trestle Rehabilitation Cost Estimate

Bridge # SA‐9


Assumptions and Approach:

Replace full length of square posts

Splice piles at each cap

Replace high priority (HP) piles/posts for 25 year lifespan

Replace HP and medium priority (MP) for 35 year lifespan

Replace HP, MP, and low priority LP for 50 year lifespan

Bent Highest Pile Rot Pile # Square / Round LP MP HP

7 LR PB round 46

9 MR PB round 56

10 none PA round 62

11 MR PA round 69

11 MR PE round 69

12 MR PA round 70

14 AR PA round 77

14 PF round 77

15 AR PA round 82

17 AR PB round 85

18 SR PA round 85

18 PF round 85

19 AR PF round 86

21 AR PA round 87

21 PD round 87

22 AR PA round 87

24 AR PA round 87

24 PD round 87

25 AR PA + PB round 174

26 PD PF round 174

26 MR PA round 87

26 PB round 87

28 AR PE round 87

29 AR PB round 83

29 PD round 83

29 PE round 83

30 SR PA round 80

Length of Pile to Replace


Post and Pile Repair Summary and Unit Cost Wilbutron Trestle Rehabilitation Cost Estimate

Bridge # SA‐9


PF round 80

31 MR PA round 78

32 AR PC round 78

32 PE + PF round 156

34 MR PA round 82

34 PD round 82

37 MR PA+PC Square 50

39 LR PA Square 25

41 none PA Square 25

43 AR (PB) PB round 20

45 LR PA Square 50

45 PC Square 50

46 MR Square 50

47 SR PB Square 25

47 PE Square 25

53 LR Square 50

54 MR Square 25

57 AR (PD) PA Square 25

57 PD Square 25

58 AR (PD) PD Square

LP MP HP

Round 1051 996 851

Square 225 75 125

Total 1276 1071 976

Estimated No. of Pile Splices 42 40 34

Estimated Post Replacements 10 10 10

LifespanEstimated No. of

Pile SplicesUnit Costs

Estimated Post

ReplacementsUnit Costs

Up to 25 years 44.00 16,000.00$ 10 14,000.00$

Up to 35 years 73.88 16,000.00$ 20 14,000.00$

Up to 50 years 115.92 16,000.00$ 30 14,000.00$

POST FULL REPLACEMENT

Post Replacement ‐ LP EA 14,000.00$ Unit costs from Tokul Creek Trestle Bid Tab used as a guide

Post Replacement ‐ MP EA 12,500.00$

Post Replacement ‐ HP EA 11,000.00$

Level 1 EA 15,000.00$

Level 2 EA 15,000.00$

Level 3 EA 15,000.00$

Level 4 EA 15,000.00$

PILE SPLICE

Pile Splice ‐ LP EA 16,000.00$ Use full replacement cost plus extra for splice

Pile Splice ‐ MP EA 14,500.00$

Pile Splice ‐ HP EA 13,000.00$

Splice fabrication and insta EA 3,000.00$ Level 1 EA 18,000.00$

Level 2 EA 18,000.00$

Level 3 EA 18,000.00$

Level 4 EA 18,000.00$


Cap Repair Summary and Unit Cost Wilbutron Trestle Rehabilitation Cost Estimate

Bridge # SA‐9


Topmost Caps Assumptions and Approach:

Replace full length of cap

Replace high priority (HP) piles/posts for 25 year lifespan

Replace HP and medium priority (MP) for 35 year lifespan

Replace HP, MP, and low priority LP for 50 year lifespan

Bent LP MP HP

1 14

2 14

3 14

4

5

6

7

8

9 14

10

11

12 14

13 14

14

15 14

16 14

17

18 14

19 14

20

21 14

22 14

23

24 14

25 14

26

27

28 14

29 14

30

31

32

33 14

34 14

Topmost cap

Length by Repair Priority



Bridge # SA‐9


35 14

36 14

37 14

38 14

39 14

40 14

41 14

42 14

43 14

44 14

45 14

46 14

47 14

52 14

53 14

54 14

55 14

56 14

57 14

58 14

59 14

60

61

62

63

64 14

LP MP HP

98 238 224

560 Ft top cap to replace

High Level Cap at Tops of Piles/Posts


Total Linear Feet 560 462 224

Pile Caps (EA) 40 33 16

Cost (EA) 5,000.00$ 5,000.00$ 5,000.00$

Total Cost 200,000.00$ 165,000.00$ 80,000.00$

HIGH LEVEL CAPS

Unit Cost

High Level Cap EA 5,000.00$ Unit costs from Tokul Creek Trestle Bid Tab

MID‐LEVEL CAPS

Unit Cost

Level 1 EA 20,000.00$

Level 2 EA 20,000.00$

Level 3 EA 20,000.00$

Average EA 20,000.00$

Bent



Bridge # SA‐9


Internal Cap Beams (Not at top)


Bent LP MP HP

Cap Beam

Total

Replace

Number

Average

length of CAP

BEAM to

replace

# Cap Splice

Repair Level 1 Level 2 Level 3

1

2

3

4 16.5

5 16.5

6

7

8

9

10

11

12

13

14

15

16 50

17 50

18 50

19 50

20 50

21 50

22 50

23

24 50

25

26 50

27 50

28 50

29 50

30

31 50

32

33

34



Bridge # SA‐9


Bent

35 52 52 1 52 1 1

36 0 50 1

37 52 52 1 52 1 1

38 104 104 2 52 1 1 1

39 52 52 1 52 1 1

40 52 52 1 52 1 1

41 52 52 1 52 1 1

42 104 104 2 52 1 1 1

43 52 52 1 52 1

44 37 37 1 37 1 1

45 52 52 1 52 1 1

46 52 52 1 52 1

47 0 52 1

52 47 47 1 47 1

53 47 47 1 47 1

54 47 47 1 47 1

55 25 25 1 25 1

56 25 25 1 25 1

57 50 50 2 25 1

58 25 25 1 25 1

59 25 25 1 25 1

60 0 25

61 0 25

62 25

63 52

64

LP MP HP HP

583 89 280 11 5 14 2

952 Ft internal caps to replace # of splices to replace

Mid‐Level Caps at Walkway Levels


Mid‐Level Caps (EA) 25 12 10

Cost (EA) 20,000.00$ 20,000.00$ 20,000.00$

Total Cost 500,000.00$ 240,000.00$ 200,000.00$


Bracing Replacement Summary Wilbutron Trestle Rehabilitation Cost Estimate

Bridge # SA‐9


Longitudinal Braces 6x12

Bent Longitudinal Repair Priority

LP MP HPLength of xbrace to replace

per bent

1 0

2 30.5 30.5

3 0

4 0

5 0

6 0

7 0

8 0

9 61 61

10 122 122

11 30.5 30.5

12 278.5 278.5

13 267 267

14 152.5 152.5

15 0

16 0

17 0

18 0

19 0

20 30.5 30.5

21 0

22 103 103

23 30.5 30.5

24 30.5 30.5

25 30.5 30.5

26 0

27 30.5 30.5

28 122 122

29 0

30 61 61

31 0

32 61 61

33 0

34 61 61



Bridge # SA‐9


Bent 0

0

35 0

36 61 61

37 122 122

38 206 206

39 93.5 93.5

40 164 164

41 84 84

42 175.5 175.5

43 42 42

44 248 248

45 93.5 93.5

46 208 208

47 61 61

52 0

53 0

54 82 82

55 63 63

56 227 227

57 30.5 30.5

58 93.5 93.5

59 91.5 91.5

60 288 288

61 84 84

62 51.5 51.5

63 0

64

429 824 2819

LP MP HP 4072

6x12 Longitudinal BracesUp to 50 years Up to 35 years Up to 25 years

6x12 Longit. Brace (LF) 429 824 2819Cost (EA) 95.00$ 90.00$ 85.00$



Bridge # SA‐9


Lateral Braces

Bent Xbrace Repair Priority

LP MP HP Length of xbrace to replace Number Average

1 none

2 none

3 none

4 none

5 none

6 none

7 none

8 19 19 1 19

9 none

10 none

11 none

12 none

13 none

14 none

15 none

16 68 68 2 34

17 none

18 136 136 4 34

19 none

20 none

21 none

22 none

23 136 136 4 34

24 87 87 3 29

25 none

26 none

27 none

28 136 136 4 34

29 none

30 none

31 none

32 none

33 none

34 none



Bridge # SA‐9


Bent

35 261 261 9 29

36 290 290 10 29

37 120 120 6 20

38 348 348 12 29

39 200 200 10 20

40 406 406 14 29

41 377 377 13 29

42 290 290 10 29

43 340 340 10 34

44 442 442 13 34

45 374 374 11 34

46 348 348 12 29

47 100 100 5 20

52 48 48 3 16

53 16 16 1 16

54 32 32 2 16

55 95 95 5 19

56 57 57 3 19

57 48 48 3 16

58 48 48 3 16

59 32 32 2 16

60 48 48 3 16

61 0

62 80 80 4 20

63 150 150 5 30

64 0

792 2161 2179

LP MP HP 5132ecommended to be repa

3x9 Lateral Braces


Lateral Brace (LF) 5132 4340 2179

Cost (EA) 85.00$ 80.00$ 75.00$



Bridge # SA‐9


Bent LP MP HP Cross Beam Total Replace Number

Average

length of

cross

brace to

replace

1 0

2 0

3 0

4 16.5 16.5 1 16.5

5 16.5 16.5 1 16.5

6 0

7 0

8 0

9 0

10 0

11 0

12 112 112 4 28

13 164 164 4 41

14 0

15 0

16 100 100 2 50

17 150 150 3 50

18 100 100 2 50

19 100 100 2 50

20 100 100 2 50

21 100 100 2 50

22 100 100 2 50

23 123 123 3 41

24 100 100 2 50

25 235 235 5 47

26 100 100 2 50

27 150 150 3 50

28 150 150 3 50

29 100 100 2 50

30 94 94 2 47

31 100 100 2 50

32 0 50

33 50 50 1 50

34 0 50

Cross Beams




Bridge # SA‐9


Bent 0

0

35 28 28 1 28

36 0 50

37 0 50

38 111 111 3 37

39 37 37 1 37

40 28 28 1 28

41 56 56 2 28

42 50 50 1 50

43 150 150 3 50

44 0 50

45 164 164 4 41

46 56 56 2 28

47 41 41 1 41

52 0 50

53 0 50

54 0 50

55 0 50

56 0 50

57 28 28 1 28

58 0 50

59 0 50

60 0 50

61 0 50

62 0 50

63 0 50

64 0

LP MP HP

474 1166 1370

3010 Ft cross brace to replace

Horizontal 6x12 Lateral Braces at Walkway Levels


6x12 Cross Brace (LF) 3010 2536 1370

Cost (LF) 95.00$ 90.00$ 85.00$



Bridge # SA‐9


BRACING MEMBERS

Unit Unit Cost

3x9 Treated Timber FT 80$

Furnish FT 12$

Install FT 100$


Furnish FT 14$ Unit costs from Tokul Creek Trestle Bid Tab

Install FT 100$ Unit costs from Tokul Creek Trestle Bid Tab


Furnish FT 16$ Unit costs from Tokul Creek Trestle Bid Tab

Install FT 100$ Unit costs from Tokul Creek Trestle Bid Tab


Furnish FT 19$ Unit costs from Tokul Creek Trestle Bid Tab as a guide

Install FT 100$ Unit costs from Tokul Creek Trestle Bid Tab as a guide


Railing, Decking, Steel Girders Unit Costs Wilbutron Trestle Rehabilitation Cost Estimate

Bridge # SA‐9


RAILING

Unit Quantity Unit Cost

Steel Railing LF 1950 165.00$

Unit Cost Examples

Steel Railing ‐ Basic Rail LF 115.00$ Redmond Central Connector Bid Tab (11/15)

Steel Railing ‐ Aesthetic Rail LF 200.00$ EstimateSteel Railing ‐ Average LF 165.00$

DECKING ‐ ASPHALT WEARING SURFACE


Asphalt Deck ‐ 14 foot wide deck SF 13650 45$

Timber Cross Ties 10"x10" SF 13650 43.00$ Asphalt Wearing Surface TON 239 110.00$

Asphalt Deck ‐ 12 foot wide deck SF 11700 45$

Timber Cross Ties 10"x10" TON 11700 43.00$ Asphalt Wearing Surface SF 205 110.00$

Unit Cost Examples

Timber Cross Ties SF 40.00$ Redmond Central Connector Bid Tab (11/15)

Asphalt Wearing Surface TON 110.00$ Redmond Central Connector Bid Tab (11/15)

DECKING ‐ PRECAST CONCRETE PANELS


Concrete Deck Planks ‐ 14 foot wide deck SF 13650 75.00$

Concrete Deck Planks ‐ 12 foot wide deck SF 11700 75.00$

Unit Cost Examples

Concrete Deck Planks SF 175.00$ Unit costs from Tokul Creek Trestle Bid Tab

" SF 65.00$ Redmond Central Connector Bid Tab (11/15)

PAINTING STEEL GIRDERS

Unit Cost

Painting LS 185,000$ Engr calculation and estimate

Surface Area SF 6556Cost/SF 28.22$

Painting LS 285,000$ Tokul Creek cost

Surface Area SF 4601Cost/SF 61.94$


Department of Natural Resources and

Parks - Parks and Recreation Division

Capital Planning and Development

201 S. Jackson St, Suite 700

Seattle, Washington 98104

Tel (206) 296-4232 | Fax (206) 263-6217

FILE #

REVISION

CHECKED

DRAWN

DATE

PROJ #

12/11/15

NJB

DLS, PRO

32499A

WILBURTON TRESTLE

EASTSIDE RAIL CORRIDOR

KING COUNTY, WA

CONTRACT NO. E00341E14

OF X

STEEL SPAN SECTION W/14 FT WIDE TRAIL

TYPICAL DECK

SECTIONS - CONCRETE

DECK

S-1

1

STEEL SPAN SECTION W/ 12 FT WIDE TRAIL

TIMBER SPAN SECTION W/14 FT WIDE TRAIL

TIMBER SPAN SECTION W/ 12 FT WIDE TRAIL

PRECAST CONCRETE DECK

PANEL WITH 2% SLOPE

EXISTING STEEL PLATE

GIRDERS

12'-0"

12'-0"

STRINGERS EQUALLY SPACED.

NUMBER OF STRINGERS VARIES

DEPENDING ON VEHICLE LOADING

REMOVE EXISTING TIMBER

TIES, STEEL RAILS, WALKWAY

AND RAILING.



AND RAILING.


PANEL WITH 2% SLOPE

PLACE WATERPROOFING

BARRIER. SHIM AS NECESSARY

TO ENSURE FIT UP OF PANELS

PLACE WATERPROOFING




PANEL WITH 2% SLOPE


GIRDERS

14'-0"



AND RAILING.

PLACE WATERPROOFING



14'-0"






AND RAILING.


PANEL WITH 2% SLOPE

PLACE WATERPROOFING








Tel (206) 296-4232 | Fax (206) 263-6217

FILE #

REVISION

CHECKED

DRAWN

DATE

PROJ #

12/11/15

NJB

DLS, PRO

32499A

WILBURTON TRESTLE


KING COUNTY, WA


OF X

STEEL SPAN SECTION W/14 FT WIDE TRAIL

TYPICAL DECK

SECTIONS - ASPHALT

DECK

8"x8"x12'-0" TIMBER CROSS

TIES

S-2

2

STEEL SPAN SECTION W/ 12 FT WIDE TRAIL

TIMBER SPAN SECTION W/14 FT WIDE TRAIL

TIMBER SPAN SECTION W/ 12 FT WIDE TRAIL

ASPHALT CONRETE WEARING

SURFACE WITH 2% SLOPE


GIRDERS

12'-0"

14'-0"


TIES




TIES





12'-0"





TIES





14'-0"






AND RAILING.



AND RAILING.



AND RAILING.



AND RAILING.


GIRDERS






Tel (206) 296-4232 | Fax (206) 263-6217

FILE #

REVISION

CHECKED

DRAWN

DATE

PROJ #

12/11/15

NJB

DLS, PRO

32499A

WILBURTON TRESTLE


KING COUNTY, WA


OF X

TYPICAL TRESTLE BENT REPAIR

REPLACE EXISTING PILE WITH

NEW 12" DIA. SAWN TIMBER POST.

S-3

3

TYPICAL REPAIRS - BENTS WITH FULL HEIGHT PILES

PLACE 12X12 CAP BETWEEN

NEW POST AND EXISTING PILE,

FASTEN NEW CAP TO EXISTING

HORIZONTAL BRACE

TYPICAL EXTENTS OF

OBSERVED DEFECT IN PILE

TYPICAL REPAIRS - BENTS WITH DISCONTINUOUS POSTS

REMOVE

SUPERSTRUCTURE

AND UNLOAD BENT

FOR ALL REPAIRS

REMOVE

SUPERSTRUCTURE

AND UNLOAD BENT

FOR ALL REPAIRS

REPLACE FULL HEIGHT OF

POST. SHORE CAP BEAM

ABOVE REPLACED POST USING

TEMPORARY STEEL POST AND

HYDRAULIC JACK

REPLACE FULL OR PARTIAL

LENGTH OF CAP BEAM.

EXTENSIVE SHORING WITH

JACKING REQUIRED.

REPLACE FULL LENGTH OF

BRACING MEMBER. MINIMUM

TO NO SHORING REQUIRED

REPLACE FULL LENGTH OF

BRACING MEMBER. MINIMUM

TO NO SHORING REQUIRED

BENTS 35 - 47, 52 - 60BENTS 3 - 34

Appendix C – Load Rating Calculations

Documents

Preliminary Design Report, Wilburton Trestle - East Rail ... · Wilburton Trestle – East Rail Corridor Bridge No. SA-9 Preliminary Design Report (DRAFT) Department of Natural Resources