2939 COLBY AVE EVERETT MUSEUM 2023-09-26

• I V Everett Museum of History Structural Assessment November CG Project No. 17390.10 Page 2 of 5 V interior brick wall on grid B.A new steel header with steel posts was constructed to reinforce the opening.The 1988 drawings show a portion of the original basement between grids B and E that extends below the sidewalk on Colby Avenue.This area is now closed off, but drawings were not available showing this construction. In 2001,the building was converted to a data center. As part of this remodel,several new mechanical units were on top of the roof structure, a large opening was framed into the roof and floor framing to accommodate a generator intake/exhaust system,and approximately 3000sf of a new 4" concrete topping slab was poured over top of the existing floor framing to support a new switch equipment room.The floor area under the concrete topping slab was reinforced by adding(13) new wood posts and footings in the basement.Several new wood shearwalls were added in the basement under the perimeter of the concrete topping slab in order to support seismic forces from heavy floor system. CHANGE OF OCCUPANCY Chapter 10 of the IEBC applies to existing buildings where a change of occupancy occurs. Since the existing occupancy classification is Business group B and the proposed occupancy classification is Assembly group A-3, the provisions of IEBC Sections 1002 through 1012 shall apply. We have evaluated the existing building per these sections and the following is a summary of the impacts to the gravity and lateral systems. Section 1007.1 states that buildings or portions thereof subject to a change of occupancy where such change in the nature of occupancy results in higher uniform or concentrated loads based on Table 1607.1 of the IBC shall comply the gravity load provisions of the IBC. Per the 2001 drawings,the live loads used to evaluate the floor framing were 70 psf(50psf+20psf partition loads)at the office areas, 125psf at the switch room,and 100psf at corridors and stairs.The proposed main floor plan shows office areas,corridor and stairs, a main gallery, a small gallery and a café space.The required live load for the galleries and café space is 100psf and these spaces are shown where some of the current office space is located.The floor framing under the areas that are changing from office space to gallery or café space require analysis and may likely require upgrades.The floor framing under the switch room is already designed for a higher live load than 100psf,so no analysis of this area is required. Section 1007.2 states that buildings and structures subject to a change of occupancy where such change in the nature of occupancy results in higher wind or snow risk categories based on Table 1604.5 of the IBC, shall be analyzed and shall comply with the applicable wind or snow load provisions of the IBC. Both the current risk category and the proposed risk category are II per Table 1604.5 of the IBC. No further analysis is required for wind and snow loads. Section 1007.3.1 states that where a building or portion thereof is subject to a change of occupancy that results in the building being assigned to a higher risk category based on Table 1604.5 of the IBC, the building shall comply with the requirements for IBC-code level seismic forces as specified in Section 301.1.4.1 for the new risk category. Both the current risk category and the proposed risk category are II per Table 1604.5 of the IBC. No further analysis is required for seismic loads. UPGRADES REQUIRED FOR PROPOSED TENNANT IMPROVEMENTS In addition to the possible upgrades of the gravity framing mentioned in the Change of Occupancy section above,there are required upgrades to the gravity and lateral framing due to the proposed floor plans.The floor plans provided by Capital Architects Group show the removal of several columns at the main floor and basement levels. New beams will be required to support the roof and floor framing in these areas. Also, adjacent columns and footings may require upgrades to support increased roof and floor loads.At the