THOMPSON RUN NO. 5(HOMEVILLE VIADUCT) (TS-05)
BRIDGE IS OWNED BY THE ALLEGHENY COUNTY DEPARTMENT OF PUBLIC WORKS
THIS IS A COUNTY, STATE, AND FEDERAL FUNDED PROJECT
THE PURPOSE OF THIS PRESENTATION IS TO INFORM THE PUBLIC OF THE PROJECT SCOPE, THE DETOUR DURING CONSTRUCTION, AND POTENTIAL IMPACTS TO THE COMMUNITY.
1. EXISTING BRIDGE DESIGN:
- The bridge was built in 1955 and rehabbed once, in 1981.
- Current Traffic: About 10,000 vehicles per day (9,889) with 4% Trucks (400/day)
- The bridge has 8 spans and is 775-feet long.
- From North to South, there are (3) Twin Girder Approach Spans, (1) 215-foot long Deck Truss Span, and (4) more Twin Girder Approach Spans.
- There are currently 9 joints in the bridge deck: Expansion Joints at each of the 7 Piers, and Deflection Joints (Compression Seals) at the 2 Abutments.
- The substructure includes (2) Abutments, and (7) Cast-in-Place Reinforced Concrete Piers supported on spread foundations bearing on rock.
- The bridge is not listed as Historic, but the RR corridor is Historic. The rehabilitation will have no effect on the RR corridor.
2. PROPOSED REHABILITATION WORK:
- The main focus of the rehabilitation is to replace and widen the existing bridge deck. The current deck is 26-feet wide (curb to curb) with a 5’-2” sidewalk. (Total out-to-out is 35’-2 ¼”.)
- The proposed deck width is 3-feet wider, for a total of 29-feet of roadway, and a 5-foot sidewalk. (Total out-to-out is 38’-2 ¾”.)
- The proposed cross section includes (2) 2’-8” high PennDOT “Alternate” Barriers at the curb lines, and a 7’-8” high Sidewalk Protective Fence on the outside edge of the sidewalk. In addition, a railing will be placed on top of the barrier adjacent to the sidewalk
- In addition, several beams will be spliced at the Pier locations, to eliminate deck joints at Piers 1, 2, 5, 6, and 7.
- ADDITIONAL ITEMS TO BE REPAIRED/REPLACED INCLUDE:
- Replace deteriorated Floorbeams at Piers 1, 2, 5, and 7
- Replace or Repair deteriorated girder and truss members (Typically rust-packing, deteriorated flange angles, and lacing members)
- Install Gusset Plate Stiffener (doubler) plates at four locations, and replace existing gusset plate rivets with high strength bolts to accommodate the additional loading from the widened deck.
- Replace existing steel and rocker bearings with new high load multi-rotational (Pot) bearings.
- Blast and Paint the entire superstructure (girder spans and truss span)
- Repair spalls and cracks in the existing piers and abutments (incorporating galvanic anodes into the repairs to prevent further/additional deterioration)
- Stain and Seal all of the abutments and piers for waterproofing and a uniform appearance.
- APPROACH ROADWAY:
- Limited approach roadway work. Approximately 150’ to 200’ of roadway will be reconstructed on each side of the bridge.
- New guiderail.
- Replace the existing sidewalk on each side of the bridge but no new sidewalks will be added.
- ADDITIONAL REPAIR ITEMS:
- Add drainage pipes and repair existing erosion at Pier No. 4 (near Grant Ave. Extension)
- Address some erosion near the north abutment
- Also fix the drainage issues at the south approach, new inlets and divert some of the hill side drainage.
- Replace the existing bridge lighting
- Bid were opened on May 7, 2015. Mosites Construction Company was the low bidder at $10,107,777.00.
3. MAINTENANCE OF TRAFFIC:
- The bridge will be closed during construction to both vehicles and pedestrians, allowing the contractor access to the whole bridge to reduce the construction duration.
- It is anticipated the contractor will need some access to the bridge from below the structure using Lower Bull Run Road and Grant Avenue Extension.
- May also use the utility access road from Grant Avenue Extension to the north abutment.
- Anticipated start of construction is August 3, 2015 with a closure on August 10, 2015.
- Construction is anticipated to be completed by October 19, 2016.