Residential Seismic Upgrade Northeast Imperial Avenue Portland, Oregon
Collapse as a result of seismic forces on existing structures are a risk that homeowners in high seismic regions such as Portland, Oregon. The homeowners for this project decided that it was time to strengthen their home. The best place to start is the basement. The basement walls of the building were constructed in 1921 and lacking strength to carry seismic forces. The walls were damaged, lacking adequate reinforcement, and have insufficient anchorage to the base of the wood framed house above.
To strengthen the bottom level of the building and provide suitable anchorage to the foundation, plywood sheathed wood stud walls were installed at the interior of the basement. The plywood sheathed stud walls provide shear walls to carry seismic loads from the building to the foundation. A high strength SR-Foam material was injected in a 2 inch space between the existing concrete and the plywood shear wall. The SR-Foam has three properties that are ideally suited for this application. It is strong, the existing basement wall can bear against the new stud walls, protecting the building from soil loading failing the exterior wall. SR-Foam is water resistant. The SR-Foam has been developed to be a closed cell material preventing water from penetrating into the building. SR-Foam also has large adhesive strength adding to the moisture resistant properties of the foam.
This project involved the installation of approximately 103 cubic feet of cellular SR Foam. For this project, the scope of work was for the voluntary upgrade of the existing concrete basement walls around three sides of the residence utilizing the SR FOAM BW (basement wall) System. The feature of the BW wall system is that a new stud wall is constructed in front of an existing unreinforced CMU or under-reinforced masonry or concrete wall with a minimum 2 inch space to separate the new wall from the existing wall. SR Foam is then injected in between the new stud wall and the existing wall to bond the two walls together. Benefits of this system allow the stud cavity to remain open for the placement of future wire runs and pipes and either wood studs or steel studs may be used for the construction of the stud wall. Additional benefits included the high insulation value (R of 7 per inch of thickness of SR Foam), reduction of water infiltration, and added shear value to the wall and the costs were less expensive than traditional reinforcing methods.
Construction: January 2013
Approximate Foam Used: 103 cubic feet
Contractor: Earthquake Tech