R. Baker & Son All Industrial Services, a specialized dismantling, rigging and demolition contractor, completed a very technical selective demolition project for Con Edison in Brooklyn, New York. Con Edison purchased the property for a future substation installation and required the demolition of the buildings on the lot.
The lot consisted of several buildings on a 225 ft x 200 ft parcel in a combination residential and commercial area near downtown Brooklyn, NY. The buildings were mostly constructed of masonry and brick walls with wooden floors and structural members. The lot was bounded on three sides by active sidewalks and a shared common wall with an occupied building on the East side. Several of the multi-story buildings had structural problems including unsafe roofs, cracked structural beams and walls that bowed outward. In addition, a hotel bounded the southeast portion of the lot which utilized the alleyway for guest parking.
Numerous tasks needed to be completed to make sure the buildings were safe to demolish as well as to protect the surrounding public and active structures. A detailed Health and Safety Plan, Work Plan and signed engineering drawings were developed to detail safe work practices and specific methodologies to complete the project.
A sidewalk bridge with scaffolding and netting and a wooden fence was placed around the entire lot. Several floors of the interior of the buildings needed to be shored to prevent uncontrolled collapse. Utility disconnects and isolations were coordinated and verified. Several fuel storage tanks and associated piping were pumped and cleaned of product which was sent offsite for recycling. All necessary permits were obtained including hot work, demolition, asbestos removal, sidewalk closing and crossing. As an additional safety measure and to ensure public safety, security was maintained 24hrs a day.
Before demolition activities could be conducted, the structures needed to be abated of asbestos containing materials (ACM). ACM consisted of roofing materials, piping insulation, boiler insulation and gaskets. The insulation and gasket materials were abated using standard asbestos removal procedures. Due to the structural instability of the roofs, a variance was obtained to abate the ACM roofs using mechanical means and wet methodology. An asbestos trained operator in a Case 9060B excavator with grapple carefully removed the roofs, while trained laborers performed dust suppression, and placed the ACM directly into lined rolloffs.
In order for the buildings to be safely demolished, several wall bracing systems needed to be installed. The wall bracing and shoring design was performed by a licensed professional engineer, which was submitted for NYC Building Department approvals. Upon approval, steel bracing was installed along the shared common wall, which needed to remain in an undamaged condition, as well as along the northern basement wall.
Safety for workers and the surrounding public was first and foremost throughout the entire project. The dedicated Site Safety Officer, Mr. Henry Walburger, conducted daily safety meetings and made sure that proper safety procedures were always followed. Workers not only wore standard Level D PPE but also put on high visibility safety vests. Mr Walburger also made sure that dust suppression was maintained and that spotters were utilized along the perimeter to ensure public safety.
A significant amount of manual demolition needed to be conducted prior to any mechanical demolition. As part of the demolition permit, structures needed to be manually brought down to fewer than 2 stories in height. In addition, careful surgical demolition needed to be conducted to separate the structural members along the shared common wall which needed to remain. Workers with saw-salls and chipping guns working off of JLG lifts and scaffolding carefully made the necessary separations and gaps.