Proposed 2nd Floor Addition

Project Details

This project involves the structural design and engineering for a second-floor addition to an existing residential property. The comprehensive scope required modern engineering solutions for the entire new structural assembly, including roof trusses (RT1), floor joists (FJ1, FJ2, FJ3), beams, posts, and shear walls to ensure both vertical and lateral stability. The primary structure utilizes Douglas Fir Larch (No. 1 for beams and No. 2 for joists/rafters) integrated with Structural I plywood sheathing and a suite of high-performance connectors, including Simpson Strong-Tie HDU hold-downs, column caps, and post bases. The design process included rigorous structural analysis, including finite element modeling for roof trusses and diaphragm checks, to ensure the addition could safely withstand environmental loads. The structural elements were engineered in accordance with the 2022 California Building Code (CBC), IBC 2021, and ASCE 7-16 provisions. Special attention was given to lateral load resistance through the implementation of a shear wall system designed for Seismic Design Category D and wind speeds of 95 MPH (Exposure B). The foundation analysis verified that the existing reinforced concrete footings perform reliably under a design soil bearing capacity of 1,500 psf.

Role

Structural Engineer/Designer

Services Provided

The scope of structural engineering services included the preparation of comprehensive structural calculations and structural drawings for the proposed project improvements. Structural calculations were conducted to evaluate load-bearing analysis for wind, seismic, dead, and live loads in accordance with applicable building codes and standards. The work included the structural analysis and design of all new structural elements required for the project, including but not limited to foundations, shear walls, load-bearing walls, columns, beams, floor joists, rafters or trusses, and all associated connectors and fastening systems. The calculations verified the structural adequacy of each component to safely support applicable gravity and lateral loads and ensured a continuous and code-compliant load path throughout the structure.
Structural drawings were prepared to clearly illustrate the structural design for permitting, coordination, and construction. The drawing set included a Foundation Plan identifying the layout of the existing foundations and areas where strengthening or modification was required; a Second Floor Framing Plan and Roof Framing Plan showing the configuration, spacing, and sizing of framing members; and Shear Wall Layout Plans for both the First Floor and Second Floor, including the identification of existing shear walls to remain and areas requiring strengthening as necessary. The drawings also included structural sections to clarify vertical relationships and load transfer, along with typical structural details, general structural notes, and technical specifications necessary to guide construction and ensure compliance with applicable codes and project requirements.