Maclay Bridge Rehabilitation Jai B. Kim, PE, PhD Robert H. Kim, PE, - - PowerPoint PPT Presentation

Maclay Bridge Rehabilitation

Jai B. Kim, PE, PhD Robert H. Kim, PE, MSCE Phone: (570) 490-7811 Email: jaikim@bucknell.edu

Maclay Bridge Components

Maclay Bridge Components

Arch Rehabilitation Concept

Maclay Bridge Background

• Built 1935, rehabilitated 1964.
• Pin-connected Parker truss main span = 180.1 ft

and Warren pony truss span = 39 ft, Roadway 16 ft; Traffic = 1,890 (2014).

• Present weight limit: 11 tons.
• Listing in the National Register of Historic Places

(NRHP) is pending.

• Abstract: The economic situation requires that the

bridge should usefully serve its purpose for as long as possible. Various methods of strengthening would help to prolong its useful life.

Maclay Bridge Conceptual Alternatives

Five Possible Alternatives:

• 1. Rehabilitate with arches for 36 tons - Parker truss main

span with pedestrian/bikeway.

• A. Replace the Pony and concrete spans with new

single span to allow for removal of the piers.

• 2. Widen the trusses to 26’ 0’’ from existing 17’ 2” for two

10-ft traffic lanes (one lane each direction) plus 2-ft shoulders and 4’ 6” pedestrian/bikeway, and increase the live load capacity. Replace the Pony and concrete spans with new single span to allow for removal of the piers.

• 3. A new one-lane Parker truss bridge parallel to the

rehabilitated existing Parker truss bridge. Have the rehabilitated Parker truss bridge listed in the NRHP.

Maclay Bridge Conceptual Alternatives

Five Possible Alternatives (cont’d):

4.Construct a new two-lane bridge (one lane each direction) concrete or steel beam parallel to the rehabilitated existing Parker truss bridge which will be used for pedestrians/bikeway only. 5.Replace the existing Parker through truss bridge with a new similar, wider two-lane Parker through truss bridge.

Maclay Bridge Conceptual Alternatives

Alternative 1: Rehabilitate with arches for 36 tons - Parker truss main span with pedestrian/bikeway.

• The MDT Bridge Design Standards, SURFACE

TRANSPORTATION PROGRAM (STP) Secs A) 1) and D) 3) f) Truss Rehabilitation requirements may be met .

• Design for HS-20 (36 tons).
• List in the NRHP after the rehabilitation as done

in Maryland, New York, and Pennsylvania after the arch rehabilitation.

Maclay Bridge Conceptual Alternatives

Alternative 1 (cont’d): Rehab with arches for 36 tons - Parker truss main span with pedestrian/bikeway.

• Rehabilitate the bridge as quickly as possible for

the safety of traveling public.

• Keep the cost of rehabilitation as low as possible.
• Protect the surrounding environment from the

impact of the construction (no impact on the river).

• Rehabilitated bridge will have least amount of

changes to the historic site and aesthetics.

Maclay Bridge Conceptual Alternatives

Alternative 1 (cont’d): Rehab with arches for 36 tons - Parker truss main span with pedestrian/bikeway.

• Add structural redundancy and remove the fracture
• critical

characteristics of the bridge.

• No need for new foundations and new piers.
• Costs will be lower: estimated to be $4,000 to $7,000 per

lineal ft of bridge. For 180’ main Parker truss, the costs could range from $720,000 to $1,260,000 for short construction time period, with intermittent traffic on the bridge.

• Costs for approach spans would depend on option chosen

(rehab existing spans with sidewalk on down stream side ~$280K or remove two piers and replace with single span Parker truss with sidewalk on one side ~$800K).

Maclay Bridge Conceptual Alternatives

Alternative 1 (cont’d): Rehab with arches for 36 tons - Parker truss main span with pedestrian/bikeway.

• No waterway disturbance with new piers.
• No need for acquiring new right-of-way properties.
• During some phases of the rehabilitation, traffic will

be allowed on the bridge.

Maclay Bridge Conceptual Alternatives

Alternative 1 (cont’d): Rehab with arches for 36 tons - Parker truss main span with pedestrian/bikeway.

Maclay Bridge Conceptual Alternatives

Alternative 1 (cont’d): Rehab with arches for 36 tons - Parker truss main span with pedestrian/bikeway.

Pedestrian/Bike Way can be on either side

• f bridge (upstream
• r downstream)

Maclay Bridge Conceptual Alternatives

Alternative 1 (cont’d): Rehab with arches for 36 tons - Parker truss main span with pedestrian/bikeway.

Maclay Bridge Conceptual Alternatives

Alternative 1 (cont’d): Rehab with arches for 36 tons - Parker truss main span with pedestrian/bikeway.

Lycoming County, Pennsylvania, 62 ft Pony Truss from 5 tons to 36 tons

Maclay Bridge Conceptual Alternatives

Alternative 1 (cont’d): Rehab with arches for 36 tons - Parker truss main span with pedestrian/bikeway.

Lycoming County, Pennsylvania, 62 ft Pony Truss from 5 tons to 36 tons

Maclay Bridge Conceptual Alternatives

Alternative 2: Widen the trusses to 26’ 0’’ from existing 17’ 2” for two 10-ft traffic lanes (one lane each direction) plus 2-ft shoulders and 4’ 6” pedestrian/bikeway, and also increase the live load capacity. Replace the Pony and concrete spans with new single span to allow removal of the piers. References: Checkered House Bridge, Vermont; and the Huey P. Long Bridge, New Orleans, Louisiana.

Maclay Bridge Conceptual Alternatives

Alternative 2 (cont’d): Widening the trusses to 26’ 0’’ from existing 17’ 2” for two 10-ft traffic lanes…

• Increased bridge live load capacity to an HS-20

(36 tons) with the least changes to the bridge in its original material and aesthetics so that the bridge may be listed in the NRHP.

• The MDT Bridge Design Standards, SURFACE

TRANSPORTATION PROGRAM (STP) A) 1) & D) 3) f) requirements may be met.

Maclay Bridge Conceptual Alternatives

Alternative 2 (cont’d): Widening the trusses to 26’ 0’’ from existing 17’ 2” for two 10-ft traffic lanes…

• The rehabilitated Parker truss bridge will carry two

lanes, one lane each direction.

• No new foundations and piers in the water ways

will be needed, since the new W frame pier caps anchored to the existing piers will support the widened bridge.

Maclay Bridge Conceptual Alternatives

Alternative 2 (cont’d): Widening the trusses to 26’ 0’’ from existing 17’ 2” for two 10-ft traffic lanes…

• Costs will be lower: estimated to be maximum

$7,000 per ft of Parker truss bridge.

• The Pony truss and concrete approach spans

would be widened to maintain compatibility with the main Parker truss span or replaced with single span to allow removal of the piers.

• Cost of approach spans would depend on
• ption chosen.
• Short construction time period.
• No waterway disturbance.

Maclay Bridge Conceptual Alternatives

Alternative 2 (cont’d): Widening the trusses to 26’ 0’’ from existing 17’ 2” for two 10-ft traffic lanes…

Pedestrian/Bike Way can be on either side

• f bridge (upstream
• r downstream)

Maclay Bridge Conceptual Alternatives

Alternative 2 (cont’d): Widening the trusses to 26’ 0’’ from existing 17’ 2” for two 10-ft traffic lanes…

Maclay Bridge Conceptual Alternatives

Alternative 2 (cont’d): Widening the trusses to 26’ 0’’ from existing 17’ 2” for two 10-ft traffic lanes…

Historic Preservation – Truss Separation Widens Historic Vermont Bridge The Checkered House Bridge (built 1929) moved 12

• ½ ft

(September 2012, Civil Engineering)

Maclay Bridge Conceptual Alternatives

Alternative 2 (cont’d): Widening the trusses to 26’ 0’’ from existing 17’ 2” for two 10-ft traffic lanes…

Maclay Bridge Conceptual Alternatives

Alternative 3: A new one-lane Parker truss bridge parallel to the rehabilitated existing Parker truss

• bridge. Have the rehabilitated Parker truss bridge

listed in the NRHP. Great River Bridge Westfield, MA

Maclay Bridge Conceptual Alternatives

Alternative 3 (cont’d): A new one-lane Parker truss bridge parallel to the rehabilitated existing Parker truss bridge…

• Save the existing landmark Parker truss bridge.
• The rehabilitated Parker truss bridge will remain

as it is with one-way traffic lane and rehabilitated for HS-20 live loading (36 tons).

• The new parallel Parker truss will be for one-way

traffic lane and is designed for HL-93 loading.

• Costs and construction time: To be determined.
• Have the rehabilitated bridge listed in the NRHP.

Maclay Bridge Conceptual Alternatives

Alternative 4: Construct a new two-lane bridge (one lane each direction) concrete or steel beam parallel to the rehabilitated existing Parker truss bridge for pedestrians/bikeway only.

• The new bridge will carry two lanes, one lane

each direction and will be designed for HL–93 loading.

• Retain the rehabilitated Parker truss bridge as-is

to carry only pedestrian/ bicycle traffic.

• The new bridge will need new foundations and

piers.

Maclay Bridge Conceptual Alternatives

Alternative 4 (cont’d): Construct a new two-lane bridge (one lane each direction) concrete or steel beam parallel to the rehabilitated...

• Have the existing rehabilitated Parker truss bridge

listed in the NRHP.

• Estimated Cost: To be determined.

Maclay Bridge Conceptual Alternatives

Alternative 4 (cont’d): Construct a new two-lane bridge (one lane each direction) concrete or steel beam parallel to the rehabilitated...

Maclay Bridge Conceptual Alternatives

Alternative 5: Replace the existing Parker through truss bridge with a new similar, two-lane Parker through truss bridge.

• Carry two lanes, one lane each direction.
• Meets a minimum MDT Bridge Design Standards

Surface Transportation Program (Secondary & Off System) with two 10’ lanes and 1’ offsets.

• Design for HL-93 loading.
• Cost: To be determined.

Maclay Bridge Conceptual Alternatives

Alternative 5 (cont’d): Replace the existing Parker through truss bridge with a new similar, wider two- lane Parker through truss bridge.

Maclay Bridge Concerns

(ref. www.maclaybridge.com; Oct 16, 2013 post)

1.Maclay Bridge currently violates a number of state and federal safety standards.

• Its foundation conditions are unknown.
• Response: As-built drawings show the

foundation is on driven piles.

• Response: Soil tests could be performed.

Visual inspection on Sep 18, 2016 (Sunday) showed no signs of distress in either piers or abutments.

Sunday, Sep 18, 2016 Inspection Maclay Bridge Concerns

(ref. www.maclaybridge.com; Oct 16, 2013 post)

Sunday, Sep 18, 2016 Inspection Maclay Bridge Concerns

(ref. www.maclaybridge.com; Oct 16, 2013 post)

1.Maclay Bridge currently violates a number of state and federal safety standards.

• Loaded school buses are right at the bridge’s

11 ton weight limit and fire trucks must straddle the centerline and travel 5 miles per hour.

• Response: The bridge load rating can be

upgraded to as high as HS-20 (36 tons) with bridge elements protected by modern guide rail. Maclay Bridge Concerns

(ref. www.maclaybridge.com; Oct 16, 2013 post)

• 2. Bridges have failed at the current site up to 5 times in

the past.

• Response: Current bridge configuration has been in

place since 1965. For previous bridge configurations, see historic bridge application.

• 3. The old bridge has impacted the river channel and

flood plain.

• Response: In its present state, the river channel

has been stable for many years based on vegetative growth, etc.

• Professional hydrologists have differing opinions

about the impacts of the existing bridge versus a new bridge.

Maclay Bridge Concerns

(ref. www.maclaybridge.com; Oct 16, 2013 post)

• 4. Maclay Bridge is classified as functionally obsolete.
• Response: Bridge load-carrying capacity can be

increased and made into 2 lanes to eliminate functional obsolescence pending public opinion (traffic volume restrictions may be preferable).

• Response: “Functionally obsolete” does not

necessarily mean unsafe. A functionally obsolete bridge can still safely support vehicular traffic.

• Response: “Functionally obsolete” can be refer to

deck geometry, underclearances, approach roadway alignment and width, or waterway adequacy without being unsafe for use.

Maclay Bridge Concerns

(ref. www.maclaybridge.com; Oct 16, 2013 post)

Screenshot of www.maclaybridge.com as of Sep 20, 2016

Definitions

• Functionally Obsolete
• “Functional obsolescence is a function of the geometrics of the

bridge in relation to the geometrics required by current design

• standards. In contrast to structural deficiencies, which are generally

the result of deterioration of the conditions of the bridge components, functional obsolescence generally results from changing traffic demands on the structure.” (https://www.fhwa.dot.gov/policy/2013cpr/chap3.cfm)

• “Facilities, including bridges, are designed to conform to the design

standards in place at the time they are designed. Over time, improvements are made to the design requirements. As an example, a bridge designed in the 1930s would have shoulder widths in conformance with the design standards of the 1930s. However, the design standards have changed since the 1930s. Therefore, current design standards are based on different criteria and require wider bridge shoulders to meet current safety standards.” (https://www.fhwa.dot.gov/policy/2004cpr/chap3c.cfm)

• Key Point: “Functionally Obsolete” can be subjective and may not

apply in certain cases.

Definitions

• Fracture-Critical Member (FCM)
• The AASHTO Manual for Bridge Evaluation (MBE), 2nd Edition,

defines a FCM as "steel tension members or steel tension components of members whose failure would be expected to result in a partial or full collapse of the bridge.“ (https://www.fhwa.dot.gov/bridge/120620.cfm)

• Structurally Deficient
• “Bridges are considered structurally deficient if significant load-

carrying elements are found to be in poor or worse condition due to deterioration and/or damage, or if the adequacy of the waterway opening provided by the bridge is determined to be extremely insufficient to the point of causing intolerable roadway traffic interruptions.” (https://www.fhwa.dot.gov/policy/2013cpr/chap3.cfm)

• "The classification of a bridge as structurally deficient does not

imply that it is likely to collapse or that it is unsafe.“ (https://www.fhwa.dot.gov/policy/2010cpr/chap3.cfm)

Maclay Bridge

Main Concerns (from www.maclaybridge.com)

• Functional obsolescence in accordance with

modern highway bridge standards.

• Fracture-critical design such that failure of a

single tension element (connection/joint/member) could cause a partial

• r complete bridge collapse.
• Low load-carrying capacity (presently 11 tons).

Truss Bridges

Advantages

• Can be economical to build
• E.g., Prefabricated truss bridges
• Very strong per unit weight of bridge
• Long span lengths possible
• Fewer/no piers needed as compared to

reinforced concrete bridges

• Less waterway encroachment beneath the

bridge

Truss Bridges

Disadvantages

• Regular, thorough maintenance is needed
• Bridge can be heavy
• Often fracture-critical design
• Partial or complete bridge collapse possible

from failure of a single tension component

Arch Rehabilitation of Truss Bridges

Concept & Purposes

• Superposition of structural steel arches on existing

trusses.

• Upgrades load-carrying capacity.
• Introduces structural redundancy to eliminate

fracture-critical nature.

• Can keep bridge open during parts of rehab (e.g.,

during the day at high-use times).

• Rehabilitation time period is relatively short and

cost is economical as compared to replacement.

• Can preserve original bridge architecture for

historical purposes.

Arch Rehabilitation Examples

Design by Muth Consulting Engineers & BKLB Photograph by HDR Engineering

Arch Rehabilitation Examples

Montana Rail Link | St. Regis, MT Cooper E80 Live Load (1.4 million lbs train loading) Design by Muth Consulting Engineers & BKLB

3 tons to 36 tons Carroll County MD Two 115-ft Pratt Trusses built around 1890 Mumma’s Ford Road

• ver Monacacy River

Carroll County, MD 5 tons to 36 tons Lycoming County PA 58-ft Pony Truss built 1890 Roaring Branch Bridge Lycoming County, PA 5 tons to 36 tons County of Cortland NY 158-ft Pratt Truss built 1910 Landers Corners Bridge Cortland, NY 10 tons to 36 tons for logging trucks U.S. Forest Service 258-ft center span

• n 40-ft high piers

Lucile Bridge Riggins, ID 10 tons to 36 tons KY Dept. of Transportation 139-ft Pratt Truss Built 1901 Bridge B30-KY 1471 Magoffin County, KY

Upgrade Owner Description Bridge

Partial List Of Arch Rehabs Done (Highway Bridges)

Maclay Bridge Considerations

• History
• Eligible for inclusion in the National

Register of Historic Places (NRHP)

• Cost
• Estimate of rehabilitation much lower than

new bridge (probably between $1 million and $3 million, conservatively, versus $13.1 million for new bridge)

Maclay Bridge Concept Summary Recap of Five Possible Alternatives:

• 1. Rehabilitate with arches for 36 tons.
• A. Replace the Pony and concrete spans with new single

span to allow for removal of the piers.

• 2. Widen the trusses to 2 lanes and upgrade load capacity.

Replace Pony and concrete spans with new single span to allow for removal of the piers.

• 3. A new one- lane Parker truss bridge parallel to the

rehabilitated existing Parker truss bridge.

• 4. Construct a new two- lane bridge (one lane each direction)

concrete or steel beam parallel to the rehabilitated existing Parker truss bridge for pedestrians/bikeway only.

• 5. Replace the existing Parker through truss bridge with a new

similar, wider two

• lane Parker through truss bridge.