City of Los Angeles RR Values for Holdowns in Shearwall and Wall Anchorage Assemblies

Introduction

This technical bulletin outlines the City of Los Angeles Research Report (RR) values for various Simpson Strong-Tie holdown and wall anchorage products. These values are based on the City of Los Angeles Building Code (LABC) and provide critical data for seismic and wind load applications in shearwall and wall anchorage assemblies.

Product Categories and Specifications

The bulletin details specific product lines, providing technical specifications, installation instructions, and allowable load tables. Key product categories include:

Holdowns (PHD, HDQ8, HDC, HD/HDA)

These products are designed for overturning requirements and transferring loads in shearwall and wall anchorage assemblies. They feature various installation methods and material specifications, with detailed tables for dimensions, fasteners, and allowable tension loads.

Tension Ties (LTT/HTT)

LTT and HTT tension ties are used in shearwalls and are designed to transfer tension loads. Specifications include material, finish, installation, and allowable tension loads based on City of L.A. RR values.

Straps (LSTA/MSTA/CMST)

LSTA, MSTA, and CMST straps are used in shearwalls and as floor ties. The document provides details on their dimensions, fasteners, and allowable tension loads, with specific notes on installation and material options.

Adhesives (SET, ET, AT)

Simpson offers various adhesive anchoring solutions, including SET Epoxy, ET Epoxy, and AT Acrylic-Tie. These are ideal for threaded rod anchoring and rebar dowelling, with specifications on load values, ease of installation, and code compliance.

Anchor Bolts (SSTB)

SSTB anchor bolts are designed for various concrete and masonry wall constructions. The bulletin includes selection guides, installation instructions, and allowable tension loads for different concrete strengths and installation conditions.

Screw Anchors (Titen HD)

Titen HD screw anchors are presented as a replacement for cast-in-place anchor bolts, suitable for retrofit applications. Information on their characteristics, installation, and use in braced wall lines and shearwalls is provided.

Bearing Plates (BP)

Bearing Plates are designed to provide greater bearing surface and help distribute loads at critical connections, meeting specific LABC requirements for sill plate anchors and holdown studs/post bolts.

Screws (SDS)

Simpson Strong-Drive SDS screws are highlighted for their ease of driving and installation without predrilling. Specifications include material, finish, and allowable shear loads.

Installation and Code Compliance

Throughout the document, emphasis is placed on proper installation procedures, including the use of specified fasteners, adherence to dimensional requirements, and considerations for wood member sizing. All products and their applications are referenced against relevant City of Los Angeles Building Code sections and Research Reports, ensuring compliance for structural integrity.

General Notes and Warnings

Important notes are provided regarding fastener requirements, wood member compatibility, and load adjustments for seismic and wind conditions. Users are advised to consult the current Wood Construction Connector catalog for general notes and warranty information. For holdowns, it is specified that anchor bolt nuts should be finger-tight plus 1/3 to 1/2 turn with a hand wrench, with care taken not to over-torque. Impact wrenches should not be used.

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