Tab 02 post Basis of Design 65 percent 2023 10 03.pdf

CUI

Controlled by: GSA Region 3

POC: Paul McIntyre, PMP

Telephone: (215) 446-4712

CUI

Altmeyer Columns Full Repair

Design

Altmeyer

Woodlawn, MD

General Services Administration

BASIS OF DESIGN

65 Percent Submission

3 October 2023

Contract Number: 47PD0322D0008

Order Number: 47PD0223F0076

Our Ref: 214.029

7900 Westpark Dr., Suite A405

McLean, VA 22102

SSA Altmeyer Structural Column Repair Study | 47PD0322R0008 Altmeyer | Woodlawn, MD

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BASIS OF DESIGN

PROPOSED CONSTRUCTION PHASING APPROACH

1. This project supports repairing five columns in the Basement of the Altmeyer Building at the Social Security Administration (SAA) Woodlawn Headquarters campus in Woodlawn, Maryland. The columns to be repaired are AS-37, AR-35, AR-37, AT-37, and AU-37.

2. The repaired columns are surrounded by various utilities, including steam and condensate piping, electrical, water, natural gas, sprinkler, and wiring for controls, and fire alarm.

3. The columns will be temporarily supported to facilitate segmented repairs based on the structural design. Utilities will be relocated as necessary to accommodate the proposed shore posts, steel plates, anchors, base plates, and shoring beams.

4. After completing the repairs, a reinforced concrete jacket will be added to enlarge the existing columns by about 5 inches on each side. This jacket aims to prevent the need for future repairs and will be applied to all columns except AU-37.

5. To perform the repairs, the Contractor must remove utilities and items like catwalks, access ladders, and steel framing within approximately 24 inches of the existing columns.

Structural drawings outline modifications to access ladders, mezzanines, grating, and other structural elements, which need close coordination with mechanical work during construction to maintain access, maintainability, and operation.

6. Ensuring the central heating plant's continued operation is vital for the Headquarters complex. Some utilities may be temporarily demolished, capped, and reconnected after repairs, while others require permanent relocation. Many of these utilities are crucial for the boiler plant, which provides high-pressure steam for heating the main complex, including the Robert M. Ball Building, Annex Building, West High-Rise Building, West Low- Rise Building, East High-Rise Building, and East Low-Rise Building.

7. Ensuring uninterrupted operation of the central steam utility plant is vital for project success. The boiler plant experiences semi-annual scheduled shutdowns, commencing at 6:00 PM before the holiday weekends indicated. During these planned outages, the Contractor must complete as much essential work as possible to preserve a seamless workflow and adhere to the project schedule.

.1 Spring Shutdown: Juneteenth weekend

.2 Fall Shutdown: Columbus Day weekend

8. The project pricing will be itemized for each column, covering all associated expenses, such as utility relocations, mezzanine and catwalk adjustments, structural shoring and repairs, as well as the expenses to restore the boiler plant to its original operational state.

.1 Base Bid: Demolition of Boiler #4, utility demolition and relocations, mezzanine and catwalk modifications and expansion, DA tank relocation, boiler feedwater pump and associated piping, and structural repairs associated with Column AS-37.

.2 Bid Option 1: Utility demolition and relocations, mezzanine and catwalk modifications, condensate tank relocation, and structural repairs associated with Column AR-35.

.3 Bid Option 2: Utility relocations, mezzanine and catwalk modifications, and structural repairs associated with Column AS-35.

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.4 Bid Option 3: Includes utility relocations, mezzanine and catwalk modifications, and structural repairs associated with Column AT-37.

.5 Bid Option 4: Includes utility relocations, mezzanine and catwalk modifications, and structural repairs associated with Column AU-37.

9. Base Bid – Repair of Column AS-37

.1 Boiler #1 will be shut down and preserved for the entire duration of the work using dry packing with desiccant to prevent additional corrosion on both the waterside and fireside. The process for dry lay-up is as follows:

a. Coordinate the shutdown of Boiler #1 a minimum of 4 weeks in advance with the Contracting Officer, and the Social Security Administration.

b. Perform a bottom blow-down before, and then again after shutdown to remove sediment and lower the boiler’s pressure and temperature until the boiler reach 0-PSIG, and water temperature is under 140-degrees F. Utilization of the boiler’s safety valve for venting is not permitted.

c. Shut off the main fuel and power supply to the boiler to ensure it's completely disconnected from external energy sources.

d. Drain all water from the boiler, including the steam and water sides through low points and drains. Contractor shall ensure no residual water remains.

Upon completion of the drain-down process, open all vents and inspection ports to allow for proper ventilation and air circulation within the boiler.

e. Open, clean, and inspect the boiler fireside. Follow the manufacturer’s instructions for minimization of metal removal during cleaning.

• Thoroughly examine the boiler for rust and scale trails on the pressure vessel boundary and record any suspicious conditions for submission to the Contracting Officer and subsequent evaluation by the Government.

• Inspect and document fireside gaskets for signs of soot trails to evaluate potential combustion gas short-circuiting, corrosion of the gasket seating surface, and indications of overheating of air-cooled surfaces.

• Inspect the fireside refractory and insulation for cracks and document any discovered.

f. Ensure that the outlet, feed, and make-up valves are securely locked and tagged as closed, while the air vent valve is locked and tagged as open.

Proceed to remove all inspection opening closures. During this process:

• Inspect for indications of gasket leakage and potential corrosion of the gasket seating surface. Examine all handhole and manway yoke bolts and nuts for any signs of deterioration. Evaluate the scale and corrosion condition on the waterside. Document and report any suspect conditions.

g. Thoroughly wash down the boiler and ensure the removal of all scale and sediment from the washout openings at the boiler's bottom. Complete removal of scale and sediment is essential to prevent the entrapment of moisture and oxygen, which can ultimately result in corrosion of the boiler.

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h. Dry all boiler surfaces using fans and electric air heaters. Power for heaters may be sourced from local electric circuits.

i. Within 7 days of finishing the wash down and before packing and sealing the boiler, submit a written copy of all documentation from the cleaning process to the Contracting Officer for review and approval. Government-conducted third-party inspections may be required to assess the Contractor's findings.

These inspections must be organized and attended by the Contractor.

j. Before sealing the boiler, place moisture-absorbing material such as silica gel or lime (also known as unslaked lime, quick lime, calcium oxide, burnt lime, calx, and caustic lime) in the waterside. The material shall be placed in a flat tray or pan inside the boiler prior to closing and sealing all boiler openings.

Renew or redry the material every three months for the duration of the project. Swab the interior of the fireside with mineral oil. Insert a piece of sheet metal between the boiler exhaust flange and stack flange.

k. Seal all openings and manholes securely to maintain a dry interior environment.

l. Regularly inspect the boiler during its idle period to ensure the integrity of the dry lay-up process and address any issues promptly.

m. Contractor shall follow all applicable confined space entry procedures.

n. The Boiler #1 gas train will need to be temporarily disconnected and capped off during the structural repairs and shall be reinstalled at the completion of the work as indicated on the drawings.

.2 Demolition of Boiler #4

a. Completely demolish Boiler #4 and remove it from the building, ensuring recycling and disposal compliance with federal, state, and local regulations.

b. Remove all piping for boiler feedwater, steam, venting, natural gas, fuel oil, blowdown, and relief back to designated points indicated on the drawings.

c. Carefully disconnect and remove all boiler control wiring, sensors, and control panels. Reprogram the boiler control sequences at the Operator's Workstation to exclude Boiler #4 from the system's control sequence of operation. Update the workstation's visual graphics to remove Boiler #4 and all related system components.

d. Remove boiler breeching and flue-gas recirculation ductwork as per the drawing specifications. Seal the boiler breeching ductwork.

e. Remove 6-inch 125# HPS back to steam distribution header and cap.

.3 Temporarily Relocate Softening System

a. Carefully disconnect and relocate brine tanks and water softeners to position indicated on the drawings. Extend domestic water and softened water piping to temporary location. System shall operate as before.

.4 Support Existing and Extend Mechanical Mezzanine

a. Provide structural foundations and vertical supports for existing mechanical mezzanine.

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b. Relocate remaining utilities along north face of existing mechanical mezzanine.

c. Provide structural steel framing, foundations, vertical supports, and future DA tank supports for mechanical mezzanine expansion.

.5 Prepare for and Relocate DA Tank and Feedwater Pumps

a. Carefully isolate and disconnect boiler feedwater pump #3 (FWP-3). Relocate pump onto a new concrete pad in position indicated on the drawings.

Feedwater pumps #1 (FWP-1) and #2 (FWP-2) shall continue to operate as before.

b. Provide new boiler feedwater pump #4 (FWP-4) on a new concrete pad in position indicated on the drawings.

c. Provide all boiler feedwater and feedwater recirculation piping, valves, fittings, controls, and power for FWP-3 and 4. Connect feedwater pump discharge piping to existing feedwater piping where indicated on the drawings and isolate for future use.

d. Provide 3-way manual isolation gate valves on existing 4-inch pumped condensate piping between condensate pumps PCP-1 and PCP-2, and DA Tank condensate return port. Installation of the valve assembly shall be completed during a scheduled shutdown.

e. Provide 4-inch pumped condensate piping from 3-way valve assembly to the 6-inch boiler feedwater supply header below the mezzanine. Installation of the connection to the 6-inch feedwater header shall be completed during a scheduled shutdown. The purpose of this cross-connection is to function as a bypass of the DA Tank during relocation.

f. Prepare for DA Tank relocation by providing future utility piping connections including tank vent, 4# steam, emergency make-up water bypass, pumped condensate, boiler feedwater recirculation and supply, chemical feedwater, tank drain, FWP-3 and FWP-4 supply, return, and recirculation headers, and overflow piping.

g. During a scheduled shutdown, relocate DA Tank to new mechanical mezzanine and provide all final piping connections. Reconnect all floats, controls, and sensors to operate as before.

• The DA Tank outage may extend beyond the duration of the scheduled shutdown for a maximum of 3-days, during which the system may operate in bypass using the 3-way manual isolation valve assembly.

h. Carefully disconnect and remove feedwater pumps, FWP-1 and 2. Protect and store pumps for future use. Remove boiler feedwater piping header, associated valves, controls, associated electrical feeders and conduit, and concrete pads complete. Isolate and cap piping at locations indicated on the drawings.

i. Provide metal gratings and mezzanine fall protection surrounding the DA Tank.

Temporarily infill any existing openings in grating at old DA Tank location.

.6 Relocate Remaining Utilities

a. Relocate remaining utilities which surround the column and are impacted by the structural repairs.

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.7 Repair Column AS-37

a. Repair Column AS-37 in accordance with the process outlined on the structural documents.

• Demolish slab surrounding Column AS-37 and install micropiles drilled and grouted into the bedrock to provide independent foundation support to the steel shoring.

• Disconnect the existing mezzanine and catwalk framing from Column AS- 37 and partially demolish the mezzanine framing, bar grating, railing, ship’s ladder in the vicinity of the column in order to install the temporary column shoring framing. Coordinate mezzanine and catwalk removal with mezzanine expansion framing.

• Construct steel shoring including: base frame supported by micropiles, vertical columns, upper steel frame, bracket for jacking of the column, attachment plates and stiffeners at each column face, and epoxy anchors into the column

• Jack the column gradually to relieve the load in the column while repairs are made. Install deflection monitors at the jack and at selected locations throughout the building.

• Remove existing external steel confinement reinforcing and perform repairs to the columns by removing cracked and deteriorated concrete, removing corrosion off reinforcing steel, forming and pumping concrete repair material into the prepared repair areas.

• While the concrete is removed, prepare the reinforcing steel for installation of the cathodic protection system by electrically connecting all of the exposed reinforcing steel.

• Concrete removal and placement of concrete repair mortar will be done in phases so as not to completely remove the column cross section at one time.

• After each column is repaired, the shoring connections to the column may be removed to allow access to the upper portion of the column. The vertical steel shoring members may remain in place to facilitate access for the remaining work, or may be completely removed and replaced by scaffolding for access in the remainder of the work.

• After removal of the upper connection plates on the column, install corrosion protection system to the face of the column for the full height, make connections to the existing steel reinforcing and check for continuity of all rebar. Install grounding. Install controls in an electrical box mounted on or near the column.

• Construct a circular concrete jacket around the column, encasing the corrosion protection system and providing structural confinement and redundancy.

• After the jacket is constructed and forms removed, any remaining shoring or scaffolding may be removed. Restore any framing, grating, and railings at the mezzanine and catwalks. Restore the subgrade and slab on grade.

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10. Bid Option 1 – Repair of Column AR-35

.1 Condensate Tank Relocation

a. Provide new 4-inch domestic cold water piping and isolation valve from existing 8-inch domestic water. Perform work during scheduled shutdown period.

b. Provide structural supports at mezzanine for the relocated condensate tank.

Remove existing grating to support the installation of new support steel.

c. Prepare new condensate piping. Provide temporary piping for dumping of condensate during relocation period.

d. During scheduled outage, relocate condensate tank to new position on mezzanine. Remove all condensate piping which conflicts with structural repair work, and extend to new condensate tank location on mezzanine.

Reconnect all pumps, valves, fittings, and controls to operate as before.

.2 Relocate 10-inch Storm Piping

a. Prepare for storm piping relocation by installing as much of the new storm piping as possible and prepare for changeover.

b. During an extended period of favorable weather conditions, disconnect and remove existing 10-inch storm piping. Provide connections to new storm piping and reconnect to operate as before.

.3 Modify existing catwalks

.4 Repair Column AR-35

a. Repair Column AR-35 in accordance with the process outlined on the structural documents.

• The sequence for structural repairs at AR-35 is the same as described for

AS-37.

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11. Bid Option – Column AS-35

.1 Utility Shutdowns and Temporary Relocations:

a. Condensate Receiver Tank

• The condensate receiver tank must be temporarily shutdown to allow for its permanent relocation to a location approximately centered between columns AR-35 and AR-37. In order to maximize serviceability of the equipment long-term, it is recommended that the tank is rotated 90-degrees from it’s current configuration.

• The condensate receiver tank shall not be shutdown at the same time as the DA tank being modified under repairs of column AS-37.

b. Other Items

• Coordinate with favorable weather to allow for relocation of existing 10-inch storm piping. Shutdown anticipated to take a maximum of 3-days, with much of the new piping to be installed prior to disconnection and demolition of the existing.

.2 Permanent Utility Relocations:

a. The condensate receiver tank shall be permanently shifted approximately 42-inches to the West, and rotated 90-degrees clockwise. All associated services including gravity condensate, pumped condensate, condensate recirculation, drains, ball level and floats, and controls shall be intercepted and extended to the new location. Refer to Error! Reference source not found..

b. Utility BTU flow meter FT-004 and FT-005 shall be permanently relocated away from the column along with the associated condensate piping.

c. The 10-inch storm pipe which feeds the Altmeyer Building must be permanently relocated.

.3 Repair Column AS-35

a. Repair Column AS-35 in accordance with the process outlined on the structural documents.

• The sequence for structural repairs at AS-35 is similar as described for

AS-37.

• Column AS-35 does not have external steel confinement reinforcement to remove.

12. Bid Option – Column AT-37

.1 Temporary Utility Relocations

a. Demolish existing 1-1/2” high pressure steam piping connecting to the Boiler #1 economizer. Provide new piping in similar location to operate as before upon completion of repair of column AR-37.

.2 Permanent Utility Relocations

a. Relocate existing 4-inch boiler economizer sanitary piping away from area of repair.

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b. Relocate existing water treatment piping, boiler blowdown, and boiler economizer piping away from area of repair.

c. Relocate four 1-1/2” natural gas pipes away from area of repair.

d. Demolish, relocate, and/or permanently cap existing 6-inch and 8-inch boiler vent piping away from area of repair.

.3 Repair Column AT-37

a. Repair Column AT-37 in accordance with the process outlined on the structural documents.

• The sequence for structural repairs at AT-37 is similar as described for

AS-37.

• Column AT-37 does not have external steel confinement reinforcement to remove.

• Column AT-37 does not have mezzanine framing to modify, although it does have catwalk framing and connections.

13. Bid Option – Column AU-37

.1 Temporary Utility Relocations

a. During a scheduled shutdown, several feet of the existing main high-pressure steam distribution header will need to be demolished, and a cap provided.

The connections that will be demolished are the connected to the steam supply piping which comes from Boiler #1 and Boiler #4. Given that these boilers will need to be shutdown for repairs of previous phases, the isolation and demolition of these pipes can occur during a scheduled outage at any time during the previous phases of the project.

b. Upon completion of the repairs of column AU-37, the steam header can be reconstructed in a similar configuration to operate as before.

c. Upon completion of the reconstruction of the steam header, Boiler #1 and Boiler #4 can be recommissioned for operation. This will include removal of all dry pack desiccant, check out of boiler controls, boiler safeties, gas piping, and all other boiler commissioning procedures in accordance with the manufacturer’s recommendations.

.2 Repair Column AU-37

a. Repair Column AU-37 in accordance with the process outlined on the structural documents.

• Repairs at Column AU-37 are minor and do not require shoring or removal or modification of the catwalk.

• Perform local concrete repairs by chipping out delaminated concrete and cleaning corrosion off the reinforcing steel. Place concrete repair material using form and pour method. The extent of repair is not expected to exceed 4 square feet at this column.

• The Cathodic Protection will still be installed at column AU-37. Ensure existing reinforcing steel is electrically connected by cutting a continuous vertical slot in the concrete to expose the existing stirrups and connect

Summer Consultants, Inc. 9 them electrically. Similarly, cut two continuous horizontal slots to expose all vertical reinforcing steel bars and connect them electrically. Install the cathodic protection grid on each face of the column for the full height. Encase the grid in a thin layer of concrete. Install grounding.

Install controls in an electrical box mounted on or near the column.

14. Bid Option – Corrosion protection at remaining five Columns: AR-37, AT-35, AU-35, AV-

35, AV-37.

a. Corrosion protection at the remaining columns will be installed similar to Column AU-37.