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MCB™  Mass Timber Column Base

Column Bases

This product's information may differ depending on the category of use. You are currently viewing details related to Column Bases. You can also view product information related to the category: Misc. Connectors for Engineered Wood

The MCB mass timber column base provides a standardized connection between a glulam column and concrete foundation or support. The MCB is an economical option for use in conditions where a standoff between the column and concrete is not required. Its robust design ensures reliable load transfer, making it a dependable solution for a variety of structural applications.

Key Features

  • Concealed connection for architectural aesthetics and fire protection
  • Wide range of base sizes and load capacities
  • Simple routing for CNC fabrication of columns
  • Threaded rods and leveling nuts may be used with grout pad for vertical adjustability
  • Base plate oversized holes provide horizontal adjustability
  • Recommended for use at column-to-foundation connections in any Seismic Design Category (See L-C-MCBDRIFT)

Material

  • Steel

Finish

  • Gray paint

Installation

Glulam Fabrication Notes:

  1. It is recommended to use CNC fabrication equipment to cut the glulam column, mill the column end and drill fastener holes. Accurate fabrication with hand tools is possible, but extra care must be taken to ensure precision.
  2. The column ends must be cut level to ensure proper bearing between the columns.
  3. Dowel hole and end mill locations must be located on the true centerlines of the glulam (+/- 1/32"). Dimensioning off of one edge can lead to mislocation errors, as the true width or depth of a glulam column can vary from the theoretical size. Refer to ANSI A190.1 for dimensional tolerances for the manufacture of glulam members. Deviating from the centerline more than 1/32" in either direction can lead to fit-up issues, as the connector hole oversize for the fasteners is 1/16".
  4. To reduce the likelihood of the drill bit wandering at wider columns, counterboring can be used to reduce the depth of drilling required for the dowel or bolt holes. Additionally, drilling from both sides of the column can help mitigate wander and help ensure proper hole alignment.

MCB Installation Notes:

  1. Ensure anchors are in the correct location in the foundation.
  2. Place MCB on the anchor rods and use leveling nuts and the oversized holes in the base plate to accurately position the base vertically and horizontally.
  3. Attach plate washers and nuts to anchors and install nonshrink grout between the base plate and the foundation.
  4. Lower the glulam column onto the base and install tight-fit dowels or bolts to connect the column to the base.

Options

  • Fasteners: Dowels or bolts with Fy = 36 ksi min. and Fu = 60 ksi min. Fasteners not included with the connector. 1/2"-diameter x 4-3/4"-long mechanically galvanized dowels are available (Model No. CJTPL).

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Product Information Table

Fastener Production Information and Stuff & Things
New products
Model No. W (in.) L (in.) Coating/Material Packaging Qty.
MCB11.5X11.5 11 1/2 11 1/2 Simpson Strong-Tie Gray Paint 1
MCB11.5X17 11 1/2 17 Simpson Strong-Tie Gray Paint 1
MCB13.5X13.5 13 1/2 13 1/2 Simpson Strong-Tie Gray Paint 1
MCB13.5X18.5 13 1/2 18 1/2 Simpson Strong-Tie Gray Paint 1
MCB15.5X15.5 15 1/2 15 1/2 Simpson Strong-Tie Gray Paint 1
MCB6X11 6 11 Simpson Strong-Tie Gray Paint 1
MCB8X14 8 14 Simpson Strong-Tie Gray Paint 1
MCB8X8 8 8 Simpson Strong-Tie Gray Paint 1
MCB9.5X15.5 9 1/2 9 1/2 Simpson Strong-Tie Gray Paint 1
MCB9.5X9.5 9 1/2 15 1/2 Simpson Strong-Tie Gray Paint 1

Load Tables

MCB Allowable Downloads

Model No. Base Plate Size (in.) Allowable
Downloads (lb.)
W L T
MCB6x11 6 11 3/4 75,500
MCB8x8 8 8 3/4 71,500
MCB8x14 8 14 3/4 165,500
MCB9.5x9.5 9.5 9.5 3/4 123,000
MCB9.5x15.5 9.5 15.5 3/4 234,000
MCB11.5x11.5 11.5 11.5 3/4 205,000
MCB11.5x17 11.5 17 3/4 328,000
MCB13.5x13.5 13.5 13.5 3/4 302,500
MCB13.5x18.5 13.5 18.5 3/4 434,000
MCB15.5x15.5 15.5 15.5 3/4 415,500
  1. See Column Base General Notes below.
  2. The MCB tabulated download values assume that the bearing area of the column has been reduced by 26.6 in2 to account for a 2-3/4"-diameter column end routing to accommodate the pipe weld to the top of the base plate and (4) 2-9/16"-diameter recesses for anchor bolt ends, nuts, and washers (See routing details). For different routing dimensions, adjust the bearing area and allowable download capacity accordingly.

MCB Allowable Uplift and Lateral loads (Wood to Steel Connection)

Model No. Minimum Column Width (in.) Minimum Column Depth (in.) Fasteners Allowable Load (lb.) (DF/SP)
Qty. Type Uplift (160) Lateral (160)
Concurrent axial compression
< 20 kips ≥ 20 kips
MCB, MCBS 8-3/4 9 2 1/2" x 4 3/4" (min.) dowel or 1/2" bolt 3,790 1,500 3,230
12-1/4 15 2,500 5,470
  1. See Column Base General Notes below.
  2. Uplift and lateral loads have been increased for wind or earthquake loading, with no further increase allowed; reduce where other loads govern.
  3. Allowable loads are based on DF/SP lumber. For SPF/HF lumber, multiply tabulated loads by 0.90 for uplift and 0.80 for lateral.
  4. For SP glulam with minimum column width 8-1/2" and 12", use loads published for width 8-3/4" and 12-1/4", respectively.
  5. For column width 6-3/4", the allowable uplift = 2,670 lb. and the allowable lateral load = 1,310 lb.
  6. For simultaneous uplift and lateral loads, the connector must be evaluated using the Unity Equation:
    Design Uplift/Allowable Uplift + Design Lateral/Allowable Lateral < 1.0
  7. Lead holes for dowels shall be drilled 0" to 1/32" smaller than the actual dowel diameter per NDS 2018/2024 Section 12.1.7.1.
  8. Holes for bolts shall be a minimum of 1/32" to a maximum of 1/16" larger than the diameter per NDS 2018/2024 Section 12.1.3.2.

Column Base General Notes

  1. Downloads shall be reduced where limited by capacity of the column.
  2. The wood member width and depth must be greater than or equal to the base plate width and depth to achieve tabulated allowable download capacity.
  3. Allowable loads are based on minimum compression parallel to grain Fc =1,950 psi. For lower Fc values, reduce allowable loads proportionally.
  4. The designer is responsible for concrete design and anchorage to concrete. Concrete support area (A2) shall be 4x the base plate area (A1). See AISC Design Guide 1, Third Edition
  5. Concrete shall have a minimum compressive strength of f'c = 3,000 psi. The grout strength shall have a minimum compressive strength of 2x the concrete strength.
  6. The base plate provides (4) 1-1/4" oversized anchor bolt holes to accommodate 3/4" anchor bolts. Anchorage by designer.

Code Reports & Compliance

Drawings

PDF DWG DXF RFA IFC SAT

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