Troy_Lock_Miter_Gate_Pre-Bid_Meeting.pdf

TROY LOCK MITER GATES

PRE-BID PRESENTATION

SITE BACKGROUND & HISTORY

• Troy Lock & Dam is located in the city of Troy, Rensselaer County, N.Y. on the Hudson River, approximately 150 miles north of New York City, N.Y.

• Construction of Troy Lock & Dam was authorized in 1910, was completed and was placed in operation in 1916.

• The lock is located on the left bank of the Hudson River, and has a usable length of 492.5 feet and a clear width of 44.4ft. Lift (at lowest stages) is 17.3 ft.

• Troy Lock is located at the head of the tidewater in the Hudson river.

-Lower pool varies between -2.73’ and 3.27’, and max low pool is -4.23 (NAVD88) -Normal upper pool is 15.6’, and maximum operating pool is 20.77’ (NAVD88) -Top of wall is 23.27’ and pool of record is 28.75’ (NAVD88)

Dam Spillway

Lock

GENERAL WORK SEQUENCE FOR NEW MITER GATES

MAJOR PROJECT EVENTS

• Site survey of existing anchorage bars & strut arms

• Dewatering activities

• Removal and disposal of existing miter gates

• Precise survey of existing pintle bases & wall quoin locations

• Removal of existing pintle bases, sill angles & associated concrete

• Setting of new pintle bases & associated concrete

• Miter gate fabrication

• Miter gate installation

• Wall quoin resurfacing

• Miter gate, sill, anchorage bar & strut arm adjustments

• Site rewatering

• Final miter gate adjustments

SITE SURVEYS

• The following existing gate components will need to be surveyed by a registered land surveyor.

- (4) Existing pintle bases

- (4) Existing wall quoins, measuring from 26’ (upper gate) to 40’ (lower gate)

- (8) Existing miter gate anchorage bars

• The new miter gates will be installed, based on this survey information.

-The new bases will be located based on the existing pintle base locations.

-The extent of wall-quoin finishing will depend on wall quoin surveys.

-The new anchor bars will be located similarly to existing locations.

In addition to the surveys mentioned above, the miter sill and wall quoin fit-up will need to be measured before and after gates have been adjusted to ensure even bearing and sealing surfaces have been established.

DEWATERING/REWATERING ACTIVITIES

There are existing upper and lower dewatering bulkheads stored on-site, which will be used by the contractor to dewater the site. The government will not provide any any additional means for dewatering. The following list describes activities that will be required by the contractor to dewater the site.

• Submission of dewatering plan for Government approval.

• Diving operations to inspect bulkhead sills/slots and remove debris/siltation.

• Installing and removing bulkheads with a crane (not supplied by the Government).

• Pumps for dewatering and materials for preventing excessive leakage.

• 2 means of egress into dewatered lock chamber.

• Any additional work required to maintain dewatered lock.

DEWATERED LOCK & EXISTING GATE PHOTOS

The following slides contain photos taken during the most recent lock dewatering, showing the existing miter gates, dewatering structures (cofferdams) and concrete.

The “UPPER” designation notes that the structure is at the north end of the lock.

The “LOWER” designation notes that the structure is at the south end of the lock.

The “RIGHT” designation notes that the structure is west, on the right descending bank, or nearer the river wall.

The “LEFT” designation notes that the structure is east, on the left descending bank, or nearer the land wall.

UPPER COFFERDAM

UPPER COFFERDAM

UPPER LEFT MITER GATE

UPPER LEFT MITER GATE

UPPER LEFT MITER SILL

UPPER MITER SILL

LOOKING DOWNSTREAM

LOWER RIGHT GATE LEAF

LOWER GATE LOOKING DS

LOWER COFFERDAM

LOWER COFFERDAM SILL

LOWER RIGHT GATE

REMOVAL & DISPOSAL OF EXISTING GATES

The contractor will remove and dispose of the existing miter gates, including the gates, gudgeon and strut pins and anchorage bars, after dewatering bulkheads have been installed. The contractor may either relocate the gates on a barge for disposal, or disassembly on site and trucked off site for disposal. The contractor will be responsible for providing all materials and equipment necessary for removal and disposal.

CONCRETE REMOVAL & PLACEMENT

The contractor will be required to remove and dispose of existing concrete located at the miter gate recesses, miter sills, pintle bases and anchorage troughs as indicated on the project drawings. Blasting, expansive grouts, or large-impact will not be allowed for concrete removal.

The contractor will place new concrete and associated reinforcing, anchorages and other miscellaneous metals at the miter gate recesses, miter sills and pintle bases as shown on the project drawings, with strengths and curing times as described in the project specifications. Concrete will likely need to be protected from cold temperatures during curing.

NEW MITER GATES - FABRICATION

• The new miter gates are designed as primarily bolted structures, with welded sub-assemblies.

• Miter gates are designed with flexibility to be shop-assembled and barge-delivered OR to be pre-assembled in shop, with final assembly and installation in field with crane(s).

• Majority of bolted connections are typical ASTM A325 pre-tensioned connections.

• Majority of steel is ASTM A709, grade 50, Temperature Zone 2 Fracture Toughness.

• Majority of gate leaf welding shall follow AWS D1.5 requirements.

• Items labeled as “FCM” will require additional preparation and testing.

• Shop shall be AISC Certified in accordance with specifications.

MITER GATE DELIVERY

• Miter gates shall be delivered prior to lock closure period as described in the specifications. Gates shall be installed and adjusted within lock closure period.

• Gate may either arrive on barge or be truck-delivered to site for final assembly in the field. Delivery Plan shall be submitted prior to delivery.

• Contractor may use contract-designated staging areas on site.

• If barge-delivered, stability computations and tie-down details shall be submitted prior to delivery.

• If gates are installed by land, lockwall stability computations shall be submitted.

MITER GATE INSTALLATION

For a given miter gate leaf to be installed, the following steps must occur.

• Miter gate leaf has been placed on pintle ball

• Anchorage bars are in place and gudgeon pin has been installed

• Strut arm is in place and strut pin has been installed

• Diagonals are tensioned such that gate is plumb

Careful attention should be made to stage the installation sequence of each gate leaf component such that there are no obstructions or interferences. For example, installation of the anchorage bars prior to gate setting may create interference.

EXISTING ANCHORAGE

WALL QUOIN RESURFACING

The existing wall quoins will be resurfaced and finished with a product that meets the project specifications. Special attention will need to be made to ensure that there are adequate clearances for finishing product preparation and application. The project specifications offer two wall quoin finishing methods that have been successfully used on other USACE projects. The contractor shall submit a wall quoin finishing plan as described in the project specifications that covers the following activities:

• Surveying and cleaning wall quoins

• Maintaining setting temperatures

• Forming product and formwork shop drawings, if necessary

• Maintaining levelness during forming

• Greasing quoin blocks after setting

The finishing product manufacturer’s representative shall be present on site during wall quoin finishing.

MITER GATE ADJUSTMENTS

After the miter gates have been installed and the wall quoins have been finished, the Contractor will provide the following miter gate adjustments to ensure proper gate Operations:

• Final concrete placement setting of miter sill for 0” seal preset.

• Adjustment and filling of miter and quoin blocks with an approved backing material

• Shimming of miter guides

• Shimming and setting of miter gate anchorage bars

• Adjustment of strut arm

• Spacing of gudgeon and strut pin collars

• Final diagonal tensioning for plumbness

• Adjustment of miter gate handrails and grating

• Adjustment and greasing of pintles and pins.

• Any additional work required to ensure that the gate operates smoothly without any unusual noises, vibrations or interferences.

UPSTREAM

GATE

DOWNSTREAM

GATE