A continuous rod tiedown system is an ideal shearwall restraint system for multi-storey light-frame wood construction.
If your firm prefers these systems to be included in a deferred submittal process, there are some elements to your specification that merit consideration to ensure the proper performance of the structure being designed.
These Documents Should Include:
- Floor heights and depths need to be clearly shown on the construction documents.
- Wall heights from bottom of sill/sole plates to top of double top plates need to be clearly indicated.
- A summary of cumulative tensile and compressive forces for each wall that will be utilizing the continuous rod tiedown system.
- Maximum total deflection of each continuous rod tiedown system at each level needs to be specified on the construction document.
- Bearing plates shall be designed for bending.
- General Notes for continuous rod tiedown system design similar to the following.
The following represents some General Notes that should be added to your construction documents in a deferred submittal.
Continuous Rod Tiedown System
- The continuous rod tiedown system shall be Simpson Strong-Tie® Strong-RodTM Anchor Tiedown System for shearwall overturning restraint.
- In a multi-storey shearwall installation, the continuous rod tiedown system shall be restrained by bearing plates at each storey of the multi-storey shearwall. Shrinkage compensating devices shall be provided at each restraint location.
- Skipping storeys, where bearing plates are omitted at intermediate floors that result in multiple storeys being tied together, is prohibited.
- Unless shown otherwise on the structural plans, the computed maximum vertical travel (elongation or stretch) between restraint locations, together with computed deformations of shrinkage compensating device, within any storey short-term duration loading, such as wind or earthquake loads, shall not exceed 0.30", or 7.6 mm, or as specified. Rod elongation or stretch shall be computed as the product PL/AE, where P is the axial load (lb.), L is the initial rod length between restraints at the storey under consideration (inches), E is 29,000,000 (psi) and A is the net tensile area of the rod (in2). Device displacement shall be as specified in the evaluation report including ΔR + ΔF (PD/PR).
- Calculations and shop drawings meeting all the above requirements shall be submitted and provided by the manufacturer of the continuous rod tiedown system for review and approval prior
- Drawings provided by the manufacturer shall specify the proprietary components or systems.
- Simpson Strong-Tie wood connectors are specifically required to meet the structural calculations of the plan. Before substituting another brand, confirm load capacity based on reliable published testing data or calculations. The Engineer/Designer of Record should evaluate and give written approval for substitution prior to installation.