05_ODVA ROSEBURG_STRUCTURAL 100 SD NARRATIVE.pdf

111 SW Fifth Avenue, Suite 2600 Portland, OR 97204 503 227-3251 kpff.com

OREGON DEPARTMENT OF VETERAN’S AFFAIR

ROSEBURG, OREGON

SCHEMATIC DESIGN STRUCTURAL NARRATIVE

MAY 30, 2025

PROJECT SUMMARY

The project comprises of a new, approximately 150,000 ft2 veteran housing building in Roseburg, Oregon, located on the federal Department of Veteran’s Affair’s campus. It consists of four separate neighborhoods and a community center that are all connected together with splines. It will all be a one-story structure of wood-framed construction sitting on grade. The construction type for the wood structure will be Type V. Structural information for the building is provided in the following sections.

PART 1 – CODES, STANDARDS, AND LOADS

RELEVANT BUILDING CODE & STANDARDS

The 2022 Oregon Structural Specialty Code (OSSC) will be the governing design document for the structural and non-structural components of this project. The following reference documents will also be used:

• Concrete Design –Building Code Requirements for Structural Concrete (ACI 318)

• Steel Design – AISC Steel Construction Manual (AISC 360)

• Timber Design – National Design Specification for Wood Construction (NDS)

• Building Loads – Minimum Design Loads for Buildings and Other Structures (ASCE 7)

DESIGN CRITERIA AND LOADING

The following design criteria shall be used for this project:

General Loading

Residential Live Load 40 psf

Corridor Live Load 100 psf

Common Area Live Load 100 psf (public access only)

Roof Live Loading 20 psf

Soil Bearing Pressure TBD psf (awaiting geotechnical investigation)

Lateral Loading

Wind Loading 97 mph, Exposure B, IW = 1.0

Seismic Loading Site Class D (assumed), SDS = 0.66g, SD1 = 0.41g

Seismic Importance Factor IE = 1.0 (Category II, Residential, Retail, Office)

Response Modification Factor R = 6.5 (wood structures)

PRELIMINARY DRAFT

PRELIMINARY DRAFT

ODVA Roseburg 2 KPFF Project No. 10022400340

SD Structural Narrative May 30, 2025

PART 2 – STRUCTURAL SCHEMATIC DESIGN

FOUNDATIONS

To date, we do not have a geotechnical report for the project. The slab-on-grade will be 4" thick. The building’s perimeter at the exterior walls and also at the interior bearing/shear walls will be continuous strip footings with a stem wall or a thickened slab. The footings will be a min. of 18” below grade and approximately 12" deep x 18" wide. At locations of posts and columns, a spread footing will be used to support the loads.

BUILDING FRAME

Exterior and Interior Walls

The headers will be constructed of built-up 2x framing, solid sawn, or glulam beams, depending on load and span length. The exterior stud wall system will be platform framed with 2x6 wood stud framing, meaning the top plates will be located at the bottom of the roof trusses and the trusses will sit on top. Double top plates and single sill plates will be provided on all walls.

The demising walls between units and the corridor walls will have 2x6 studs. The demising walls will likely be 2x6. Double top plates and single sill plates will be provided on all walls. Some of these will be used as shear walls and constructed as described below. The interior bearing walls within the units will be 2x6 studs. All interior non-bearing partitions will be framed with 2x4 studs at 24" on center and have single top and sill plates. Single 2x4 plate headers will be used at these partitions. A 3/4” gap will be left between all interior partitions and the roof trusses. Simpson STC clips or Simpson deflector screw will connect the partitions to the framing above them.

Wood Roof Framing

The roof will be framed with prefabricated wood trusses and I-joists (TJI or similar). The roof trusses will span from exterior wall to corridor or from demising wall to demising wall depending on the slopes of the roof. I-Joists will be used over the corridors. The roof will be sheathed with ⅝" T&G wood structural panel sheathing. The parapets will be built into the prefabricated wood trusses.

This design assumes no window washing loads on the parapets.

Lateral Force Resisting System

The lateral force-resisting system will consist of wood structural panel shear walls and diaphragms.

The shear walls will mostly be confined to the exterior and demising walls. A certain amount of steel strapping will help with discontinuous walls and reentrant corner conditions.

The wood shear walls will be constructed with ½" plywood on one side of the stud walls. Holdowns

(Simpson or similar) will be used at the ends of walls to resist the lateral forces. These holdowns will be attached to built-up 2x or solid 4x or 6x members at the boundaries of the shear walls and also anchored into the continuous footing below. The sills will be anchored to the concrete stem walls with cast-in anchor bolts.

ODVA Roseburg 3 KPFF Project No. 10022400340

SD Structural Narrative May 30, 2025

MISCELLANEOUS AND SECONDARY STRUCTURE

Secondary structural elements will be developed through design development and construction documents; however, we anticipate these will be required for the following:

• Secondary structural steel support for cladding backup framing as required

• Railings/guardrails

• Ladders and roof access (bidder-designed)

• Canopies

• Roof tie-offs (bidder designed)

• MEP distribution and equipment anchorage/bracing (bidder designed)

• Trash Enclosure

• Covered Entry/Porte Cochere Structure (see architectural site plan), assume foundations at each column of the structure