Proposed Renovation & Addition

Project Details

This project involves the structural design and engineering for a multi-story renovation and addition to a residential property located in San Francisco. The comprehensive scope required modern engineering solutions for a vertical expansion, including new floor systems for a three-story assembly and a new roof structure. The primary framing utilizes Douglas Fir Larch (No. 1 and No. 2) lumber, integrated with high-strength Microllam LVL floor beams and structural-I plywood sheathing to ensure a durable residential assembly. The design process included a rigorous structural analysis to ensure the building can safely withstand environmental and occupancy loads, with a specified typical floor live load of 40 psf and a roof live load of 20 psf. The structural elements were engineered in accordance with the 2022 California Building Code (CBC), 2022 California Residential Code (CRC), IBC 2021, and ASCE 7-16 provisions. Special attention was given to lateral load resistance through the implementation of a wood shear wall system using structural sheathing and Simpson Strong-Tie hold-downs (ranging from HDU2 to HDU14), providing stability against requirements for Seismic Design Category D and wind speeds of 92 MPH. The foundation system features a 4-inch thick reinforced concrete slab-on-grade (f’c=3000 psi) supported by a combination of existing footings and new independent reinforced concrete wall and pad footings designed for a soil bearing capacity of 1,500 psf.

Role

Structural Engineer/Designer

Services Provided

The scope of services included the preparation of comprehensive structural calculations and structural drawings for the proposed project. Structural calculations included complete loading analyses for wind, seismic, dead, and live loads in accordance with the applicable governing building codes and project site conditions. The work encompassed the structural analysis and design of all primary and secondary structural elements, including foundations, shear walls, load-bearing walls, columns, beams, floor joists, headers, stair stringers, guardrail posts, trusses or rafters, and all necessary structural connectors to ensure a continuous, stable, and code-compliant load path. The design process evaluated both gravity and lateral load effects to ensure adequate strength, serviceability, and overall structural performance. Structural drawings included a complete set of plans and supporting details necessary for permitting and construction. The drawing set consisted of a Foundation Plan identifying the layout and configuration of the structural foundation system; Framing Plans for the second and third floor levels showing the arrangement and sizing of beams, joists, and other framing members; and a Roof Framing Plan illustrating the structural layout of rafters or trusses and associated components. The documents also included Shear Wall Layout Plans for the first, second, and third floors indicating the location and extent of lateral force-resisting elements. In addition, Structural Building Section Views, both longitudinal and cross-sectional, were provided to clearly illustrate vertical load paths and framing relationships between building components. The drawing package was supplemented with typical structural details, general structural notes, and technical specifications necessary to ensure clarity for plan review, coordination with other disciplines, and proper implementation during construction while maintaining compliance with applicable codes and engineering standards.