The McGuire Seattle, WA

Demolition Overview

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Overview

This document describes the demolition plan for The McGuire apartment building and attached

parking structure including methods, durations, work hours, crew size, truck rate and mitigating

potential negative impacts to the neighborhood.

Method and Duration of Demolition

The McGuire will be demolished in fourteen to eighteen months over the following four phases.

Note that due to the dense urban location and lack of basement to contain debris, neither the

tower nor the parking structure will be demolished by use of explosives.

1. The parking structure will be demolished to the top of the first floor slab by Mass

Demolition. (See the next section for a description of each demolition method.)

2. Next, the tower will be demolished from the top down to approximately level six by

Floor-by-Floor Demolition.

3. The remaining floors of the tower will be demolished by Mass Demolition.

4. Finally, the below-grade foundations and substructures of the parking structure and tower

will be demolished with hydraulic excavators and the ~5’ deep excavated hole will be

filled in with gravel.

Description of Demolition Methods and Impacts to the Neighborhood

Mass Demolition uses hydraulic excavators capable of

reaching up several stories and “munching” or

“nibbling” structures from the top-down in a controlled

manner. The parking structure and the lower floors of

the tower will be demolished by Mass Demolition.

This is the ideal method for these locations because it

is safe and efficient for low-rise structures and

appropriately addresses the following neighborhood

concerns:

Safety: Mass Demolition is the safest method of

demolition for low-rise structures in dense urban

locations because it is controlled and methodical.

Noise: The hydraulic excavators generally work by “munching” instead of impact and thus

produce less noise and vibration than other demolition methods, such as hammering.

Controlled Mass Demolition by hydraulic

excavator with water misting to reduce dust

The McGuire Seattle, WA

Demolition Overview

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Dust: Misting water at the point of concrete disturbance is the best way

to reduce dust. The hydraulic excavators will be fitted with a water

hose at the mouth of the “muncher” and hand-held water hoses will be

used at truck loading.

Traffic: Extended traffic lane closures are not expected to be required

for the demolition of the McGuire. However, it is likely that parking

will be closed in the alley and that sidewalks around the building will

be closed throughout demolition. In addition, since the parking

structure comes right up to the sidewalk and alley, some portion of the

parking lane and alley will have to be closed for safety, trucking, and

access for the hydraulic excavators during Mass Demolition of the

parking structure. However, Mass Demolition proceeds bay by bay relatively quickly and the

operations will be moved within the footprint of the removed structure and streets re-opened

(with flag-persons controlling traffic flow in and around the jobsite throughout) as soon as safety

allows.

Floor-by-Floor Demolition will be used from the top of the

tower down to approximately level six. Working from the top

down, one level at a time and bay-by-bay, mini-excavators

will rubblize the floors into cobble-size pieces. This debris

will be pushed down the elevator or stairwell shafts to the

ground floor, where it will be loaded into the trucks. The

interior columns and perimeter concrete moment frame will

be cut into pieces and moved by the tower crane to the

ground, where they will be processed into cobble-size pieces

and loaded into the trucks. This is the ideal demolition

method for the top of the tower, which is too high for the

hydraulic excavators used for Mass Demolition. Floor-by-

Floor Demolition appropriately addresses the following

neighborhood concerns:

Safety: Floor-by-Floor Demolition is the safest method for

demolishing post-tensioned, exterior moment frame high-rise

structures in dense urban locations because the decks will be

detensioned in a sequential, controlled manner as the floors

are rubblized and the perimeter concrete moment frame will be carefully removed from the

building by the tower crane and processed at ground level where the debris is contained. As an

additional safety precaution, plywood will be added to the deck and outside vertical face of the

existing scaffolding at each working floor to contain broken concrete and keep it from falling

The concrete cracker is a non-impact, vibration free attachment.

The “muncher” is a non-

impact attachment that

will minimize vibration

and noise during

Mass Demolition of the

parking structure and

lower floors of the tower

The crane will remove large pieces

from the perimeter of the tower for

rubblizing on the ground to control dust

and noise in Floor-by-Floor Demolition

The McGuire Seattle, WA

Demolition Overview

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through to the ground below. Mesh will also be installed on the outside of the scaffolding at the

working floor and two floors below to further minimize the potential for escaping debris and

dust.

The Floor-by-Floor demolition

plan, sequence and load

calculations will be reviewed,

approved and stamped by a

structural engineer licensed in

the State of Washington. For

additional safety, these plans

and calculations will be peer

reviewed by an additional,

impartial (not otherwise

involved in the project)

structural engineer licensed in

the State of Washington. The

engineered plan will include

post shoring as needed to

support the floors during

demolition. The demolition and

shoring on each floor will

follow the specific plan as

dictated by the structural

engineer. No deviations will be

allowed to the plan without a

specific field change being

made to the work plan by the

structural engineer.

Noise: Floor-by-Floor demolition will not exceed the allowable noise levels in the City’s Noise

Ordinance. The project will further reduce the noise disturbance to the neighborhood by:

1. Installing plywood on the deck and outside of the scaffold at the floor of work.

2. Installing mesh on the outside of the scaffold at the floor of work and two floors below.

3. Installing solid perimeter site fencing.

4. Moving debris from each floor to the ground level within chutes inside the building.

5. Lining the sides and base of the debris chutes with sound-absorptive materials.

6. Large elements such as the interior columns and perimeter moment frame will be

processed at the ground level inside the solid perimeter site fencing.

Mini-excavators will rubblize the deck above the “work floor.” The remaining

decks will be supported by post shores designed by the structural engineer.

Plywood will be installed on the deck and interior wall of the scaffold at the

work floor and mesh will be installed on the exterior of the scaffold at the work

floor and at least two floors below to control dust and noise.

Section Through Scaffolding and Building

(Not to Scale)

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Demolition Overview

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7. Debris will be down-sized or rubblized with

the use of “muncher” attachments to limit the

use of noisy demolition hammers. Demolition

hammers use will be limited to oversized

materials or where down-sizing is impractical

by other means.

8. Planning circular truck routes to minimize the

use of back-up alarms.

9. During loading of trucks, care will be taken

not to drop rubble in the truck beds. Rather,

rubble will be lowered and spread into the

beds, front-to-back, minimizing surface-to-

surface contact during loading.

Dust: Misting water at the point of concrete disturbance is the best way to reduce dust. Hand-

held water hoses will be used at all demolition points and truck loading. In addition, the beds of

the trucks will be wetted prior to loading to prevent dust transmission during travel and wheels

will be washed and streets swept as needed. The need is expected to be minimal as lay-down area

and truck loading will occur on the concrete slab of the former parking structure, which allows

for a clean site with minimal dust and mud. Similar to the noise discussion above, the plywood

and mesh on the scaffold, solid perimeter site fencing and interior debris chutes will minimize

dust.

Traffic: Extended traffic lane closures are not expected to be required for the demolition of the

McGuire. However, it is likely that parking will be closed in the alley and that sidewalks around

the building will be closed throughout demolition and the parking lanes and alley may be closed

periodically, if needed. Flag-persons will be employed to control traffic flow in and around the

jobsite.

Foundation Demolition will be by excavators with hydraulic breakers to break the foundations

into pieces and bucket attachments to dig up the foundations. Broken pieces will be loaded into

the trucks or crushed to gravel-size for backfill of the ~5’ deep excavated hole. This method of

foundation demolition appropriately addresses the following neighborhood concerns:

Safety: Foundation demolition by excavators with hydraulic breakers and buckets is the safest

and industry standard method for demolition foundations. The demolition will be limited to the

maximum extent possible without requiring perimeter shoring, thus mitigating the safety risk of

undermining the surround sidewalks and streets.

Mini-excavators will rubblize the upper floors of the

tower and push debris down interior chutes, containing

dust and noise during Floor-by-Floor demolition

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Demolition Overview

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Noise: Breaking up 5’ thick pieces of concrete is noisy. However, this phase of the demolition is

relatively short and the noise will be contained to the greatest extent possible by the solid

perimeter site fencing.

Dust: Misting at the point of demolition and truck loading will continue to be utilized throughout

foundation demolition. The solid perimeter site fencing and street sweeping as needed will

further contain the dust.

Traffic: No street or sidewalk closures are expected during this phase. Flag-persons will continue

to maintain safe and efficient traffic flow in around the jobsite.

General Comments

Working hours will be within the allowable working hours by the City of Seattle’s noise

ordinance. Regular work hours are presently planned for 7am to 5pm on weekdays, extending to

7pm on weekdays and Saturdays from 9am to 7pm when necessary, such as during critical

operations or to maintain schedule. Work hours and the noise plan will be coordinated with

DPD.

Crew size will vary from ten to forty individuals on site per day, depending on the phase of

demolition. Mass Demolition of the parking structure and lower tower levels and Foundation

Demolition will require ten to twenty individuals. Floor-by-Floor Demolition will require

twenty to forty individuals. Some parking for workers will be provided inside the construction

boundary after demolition of the parking structure. Additional parking for workers will be

provided using local pay lots and/or use of mass transit.

Truck Rate will vary from twenty to forty trucks per day, depending on the phase of demolition.

Mass Demolition of the parking structure and lower tower levels will produce higher daily loads.

Floor-by-Floor Demolition of the upper tower will produce lower daily loads. Truck rates will

not be constant and there will be many days where no truck trips occur, while debris is

accumulating or being prepared (downsized) for shipment. Truck rates, haul routes and the

overall traffic and pedestrian plan will be coordinated with SDOT.

The McGuire Seattle, WA

Demolition Overview

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Closing

This demolition plan for The McGuire focuses on safety and mitigating impacts to the

environment and neighborhood, our top concerns.

If you have any questions or comments, please contact:

Katie Henry

Project Manager

Lease Crutcher Lewis

(206) 622-0500

katie.henry@lewisbuilds.com