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HSKP™ Heavy Seated Knife Plate Hanger

Preserve the look of mass timber beams while meeting high-demand loads with the HSKP. Offering the highest load ratings yet in our line of concealed beam hangers, the HSKP is ICC-ES code listed and tested for inter-story drift. The HSKP installs in the factory with Strong-Drive® SDCF Timber-CF structural screws, saving valuable time on the jobsite. It also offers generous fit-up tolerance for easy beam placement. The HSKP is readily available through our nationwide distribution network. Like all our products, it’s supported by our expert service teams.

Key Features

  • High capacity
  • Code listed in ICC-ES ESR 2552
  • ASTM E119 1- and 2-hour hour fire tests. resistance ratings per ASTM E119; see L-C-HSKPFIRE
  • Factory installation of connector reduces on-site labor
  • Quick field connection of beam to supporting member reduces crane cycle-time
  • Inclined screw hole feature reduces the overall screw count compared to horizontal screws
  • Options for wood-to-wood and wood-to-steel concealed connection
  • Recommended for use at beam-to-beam or beam-to-column connections in any Seismic Design Category; see L-C-HSKPDRIFT for more information

Material

  • Back and Knife Plate — 3 gauge; Bearing Plate — 1/2" 
  • Exception: HSKP5.75x19.5 and HSKP5.75x19.5-W knife plate — 3/8"

Finish

  • HSKP/HSKP-W — Simpson Strong-Tie gray paint
  • HSKP available in HDG and powder coat
  • SDCF Timber-CF screw — Yellow Zinc
  • CJTPL steel dowel — mechanically galvanized

Installation

Prior to connection of the carried beam to the HSKP hanger, carried member shall be routed to allow for the concealed installation of the HSKP and predrilled for the installation of the optional steel dowel (reference L-C-HSKPROUT). The designer shall determine the desired beam-end rout depth and bottom-of-beam rout depth for the desired concealed installation and potential fire considerations. When considering fire requirements, maximum allowable gaps and intumescent requirements shall be determined by the designer.

Note: When installing SDCF screws for the HSKP connection, do not exceed recommended seating torque values (reference L‑F‑MTINSTALL).

  • HSKP Factory Installation to Column
    • Drive the required horizontal SDCF screws at the top and the bottom of the hanger first. See Table 1 for the proper screw sizes. This will secure the hanger to the column to facilitate smooth installation of the inclined screws.
    • Drive the required SDCF inclined screws through the patent pending tab feature. Screws are inclined upward 45° and rotated inward 15°.
  • Factory Installation of Bearing Reinforcement Screws Into Beam
    • Install the SDCF22858 bearing reinforcement screws through the bottom of the carried member as required per the HSKP load table (see the image gallery's illustrations for installation locations). To ensure SDCF heads are normal to the face of the bottom of the carried member, predrill 3/16" maximum diameter x 2" minimum depth pilot holes prior to installation.
  • Factory Installation of Dowel
    • Install 1/2" diameter x 4 3/4" long dowel into 1/2” diameter predrilled hole in the carried member. Note that, while the installation of the dowel is only a requirement when considering joint rotation due to inter-story drift, the installation of the dowel can aid installation of the carried beam by guiding the carried member into position as the dowel slides into the HSKP knife plate slot. Dowel location must be centered about knife plate kerf cut. When considering inter-story drift, the vertical location of the steel dowel is to be located mid-height of the beam-floor assembly. If inter-story drift need not be considered, the final vertical location of the dowel may be anywhere within the knife plate slot provided a 1/4" minimum gap is allowed between the bottom of the dowel and the bottom of the slot to allow shrinkage of the carried beam.
  • Completing the Field Installation
    • After the beam has been placed into position, adjust the location of the carried member as needed to allow for the maximum desired gap between the carried and supporting member, install the beam seat screws into the bottom of the carried member through the two countersunk holes in the bottom of the HSKP bearing plate. See Table 1 for the proper screw size.
    • For fully concealed installations requiring a bottom filler block, the connection is to be determined by the building designer.

Related Literature

Strengthen your designs for mass timber
F-MT-HSKP23
A flier providing product and installation information for the HSKP heavy seated knife plate for mass timber beams.
Flier
Connectors, Fasteners & Anchors for Mass Timber Construction
C-C-MASSTIMBER24
A catalog featuring connectors, fasteners and anchors for mass timber and CLT construction solutions.
Catalog
Wood Construction Connectors 2024-2025
C-C-2024
A catalog including new product information as well as any applicable specification and installation instructions for wood-to-wood and wood-to-concrete structural connectors.
Catalog
Simpson Strong-Tie® HSKP Carried Beam Preparation and Installation Instructions
L-C-HSKPROUT23
Installation of the HSKP heavy seated knife plate connector requires that the carried beam be routed for a hidden aesthetic and to improve fire resistance.
Engineering Letter
Simpson Strong-Tie® HSKP™ Heavy Seated Knife Plate Hanger — Seismic Deformation Compatibility Testing
L-C-HSKPDRIFT24
Simpson Strong-Tie has evaluated the HSKP heavy seated knife plate hanger for seismic deformation compatibility.
Engineering Letter
Installation Torque & Tools for SDCF TIMBER-CF, SDCP TIMBER-CP and SDHR COMBO-HEAD Screws
L-F-MTINSTALL24
The purpose of this letter is to convey recommendations for installation of Strong-Drive SDCF TIMBER-CF Screws, SDCP TIMBER-CP Screws and SDHR COMBO-HEAD Screws.
Engineering Letter
Simpson Strong-Tie® HSKP™ Hanger CJTPL Dowel Positioning and Carried Beam Depth Considering Inter-Story Drift
L-C-HSKPBEAM24
The HSKP™ heavy seated knife plate hanger allows for the installation of a provided CJTPL 1/2"-diameter x 4 3/4"-long steel dowel pin in the carried beam.
Engineering Letter
Simpson Strong-Tie® HSKP™ Heavy Seated Knife Plate Hanger – ASTM E119 Fire Testing
L-C-HSKPFIRE24
Simpson Strong-Tie has evaluated the HSKP concealed hanger for one-hour and two-hour fire resistance ratings per ASTM E119 Standard Test Methods for Fire Tests of Building Construction and Materials.
Engineering Letter

Product Information Table

Fastener Production Information and Stuff & Things
New products
Model No. Description
HSKP5.75X14.5

(1) HSKP5.75X14.5 5 Connector
HSKP5.75X14.5KT

(1) HSKP5.75X14.5Connector
(1) CJTPL 1/2" Dia. Steel Dowel, (16) SDCF27614, (6) SDCF22858
HSKP5.75X14.5-W

(1) HSKP5.75X14.5-W Connector
(1) CJTPL 1/2" Dia. Steel Dowel, (2) SDCF27614
HSKP5.75X17

(1) HSKP5.75X17 Connector

HSKP5.75X17KT

(1) HSKP5.75X17 Connector
(1) CJTPL 1/2" Dia. Steel Dowel, (20) SDCF27614, (8) SDCF22858
HSKP5.75X17-W

(1) HSKP5.75X17-W Connector
(1) CJTPL 1/2" Dia. Steel Dowel, (2) SDCF27614, (2) SDCF22858
HSKP5.75X19.5

(1) HSKP5.75X19.5 Connector
HSKP5.75X19.5KT

(1) HSKP5.75X19.5 Connector
(1) CJTPL 1/2" Dia. Steel Dowel, (24) SDCF27614, (10) SDCF22858
HSKP5.75X19.5-W

(1) HSKP5.75X19.5-W Connector
(1) CJTPL 1/2" Dia. Steel Dowel, (2) SDCF27614, (4) SDCF22858

Load Tables

Table 1 — HSKP Wood-to-Wood Allowable Loads.

Model No. Fasteners (SDCF) Allowable Loads (lb.)
DF/SP SPF/HF
Carried Beam Carrying Column/Beam Uplift (160) Download (100/125) F2 (160) Uplift (160) Download (100/125) F2 (160)
Beam Seat Bearing Reinf. Bottom Horizontal Inclined Top Horizontal Column Beam Column Beam
HSKP5.75x14.5 (2) 27614 — (6) 27614 (8) 27614 (6) 22858 3,190 22,415 21,260 3,640 2,410 17,700 17,815 3,050
(2) 27614 — (6) 27400 (8) 27614 (6) 22858 20,115 20,040 16,190 16,230
HSKP5.75x17 (2) 27614 (2) 22858 (6) 27614 (12) 27614 (6) 22858 3,190 26,800 26,090 3,640 2,410 22,080 21,935 3,050
(2) 27614 (2) 22858 (6) 27400 (12) 27614 (6) 22858 24,505 24,140 20,570 20,350
HSKP5.75x19.5 (2) 27614 (4) 22858 (6) 27614 (16) 27614 (6) 22858 3,190 31,930 30,915 3,640 2,410 26,460 26,055 3,050
(2) 27614 (4) 22858 (6) 27400 (16) 27614 (6) 22858 28,960 29,700 24,950 24,470
  1. Fasteners: SDCF27400 and SDCF27614 = 0.390" OD by 4" long and 6 1/4" long Strong-Drive SDCF TIMBER-CF screw, respectively. SDCF22858 = 0.315" OD by 8 5/8" long Strong-Drive SDCF TIMBER-CF screw.
  2. Uplift and F2 loads have been increased for wind or seismic with no further increase allowed. Reduce where other loads govern.
  3. For HSKP installations on opposite faces (back-to-back) of the same supporting member, the minimum depth of the supporting member is 12 1/4" when using installing the SDCF27614 (6-1/4" long) bottom horizontal screws and 8 3/4" when installing the SDCF27400 (4" long) bottom horizontal screws.


Table 2 — HSKP Wood-to-Steel Allowable Loads

Model No. Carried Beam Fasteners (SDCF) Carrying Steel Member Fillet Weld Size, Length Allowable Loads (lb.)
DF/SP SPF/HF
Beam Seat Bearing Reinf. Uplift (160) Download (100/125) F2 (160) Uplift (160) Download (100/125) F2 (160)
Column Beam Column Beam
HSKP5.75x14.5-W (2) 27614 — 1/4" Continuous 3,190 22,630 22,630 3,640 2,410 19,600 19,600 3,050
HSKP5.75x17-W (2) 27614 (2) 22858 1/4" Continuous 3,190 26,800 26,800 3,640 2,410 23,215 23,215 3,050
HSKP5.75x19.5-W (2) 27614 (4) 22858 1/4" Continuous 3,190 32,935 32,935 3,640 2,410 27,455 27,455 3,050
  1. Fasteners: SDCF27614 = 0.390" OD by 6 1/4" long Strong-Drive SDCF TIMBER-CF screw. SDCF22858 = 0.315" OD by 8 5/8" long Strong-Drive SDCF TIMBER-CF screw.
  2. Uplift and F2 loads have been increased for wind or seismic with no further increase allowed. Reduce where other loads govern.
  3. Loads assume E-70XX weld material.
  4. Caution: Follow proper welding procedures and safety precautions. Welding should be in accordance with AWS standards.
  5. Welds must conform to the current AWS D1.1 structural welding code for steel.
  6. This connection involves welding 3 gauge and 1/2" steel to heavy structural steel. It should only be performed by skilled, qualified welders.


Table 3 — HSKP Minimum Carried Beam Sizes & Edge Distances

Model No. Connector Dimensions (in.) Minimum Carried Beam Sizes (in.) Minimum Edge Distances (in.)
W H L Hs Bw-min Bl-min Ws Ds eside ebottom etop
HSKP5.75x14.5
HSKP5.75x14.5-W		 5 3/4 14 1/2 9 7 2 1/2 8 6 3/4 15 1/2 1/2 n/a 1
14 15
HSKP5.75x17
HSKP5.75x17-W		 5 3/4 17 9 8 2 1/2 8 6 3/4 18 1/2 n/a 1
16 1/2 17 1/2
HSKP5.75x19.5
HSKP5.75x19.5-W		 5 3/4 19 1/2 9 9 1/4 2 3/8 8 6 3/4 20 1/2 1/2 n/a 1
19 20
  1. Side edge distances for supporting vertical columns must meet or exceed the eside table values for the carried beam. Top edge distances for supporting member 1 1/4" minimum.
  2. Bw-min and Bl-min are the minimum bearing width and length, respectively, required each side of the knife plate to achieve allowable downloads listed in Table 1 (see the illustration in the image gallery).
  3. Minimum Ws considering only fastener edge distance does not consider F2 loads. When F2 loads must be considered, minimum Ws = 7 1/4" and minimum eside = 1".
  4. When ebottom + 1/2" bearing plate thickness exceeds the lesser of 1/10 of the depth of the member or 3", consider notch reinforcement with fully threaded screws. See TEB-F-SDCFTENS for design guidance.


Table 4 — HSKP Min/Max Carried Beam Depths Considering Inter-story Drift

Model No. Floor Depth Above Carried Beam (in.) Carried Beam Depth Ds Range (in.)
ebottom = 0 ebottom = 1 1/2 ebottom = 3 ebottom = 3 1/2
Ds-min Ds-max Ds-min Ds-max Ds-min Ds-max Ds-min Ds-max
HSKP5.75x14.5
HSKP5.75x14.5-W		 6 5/8 to 7 1/2 16 1/2 18 18 21 19 1/2 24 19 1/2 25 1/2
3 3/8 to 4 1/2 16 1/2 21 18 24 19 1/2 27 19 1/2 28 1/2
No Floor 16 1/2 25 1/2 18 28 1/2 22 1/2 31 1/2 22 1/2 33
HSKP5.75x17
HSKP5.75x17-W		 6 5/8 to 7 1/8 18 24 19 1/2 27 21 30 22 1/2 30
4 1/8 to 5 18 25 1/2 19 1/2 28 1/2 21 31 1/2 22 1/2 33
No Floor 18 30 21 33 24 36 25 1/2 37 1/2
HSKP5.75x19.5
HSKP5.75x19.5-W		 6 1/8 to 7 1/8 21 28 1/2 22 1/2 31 1/2 24 34 1/2 24 36
4 1/8 to 4 1/2 21 31 1/2 22 1/2 34 1/2 24 37 1/2 24 37 1/2
No Floor 21 36 24 39 27 42 28 1/2 42
  1. When installed in the carried beam, 1/2" diameter dowel to be located vertically mid-height within the floor-beam assembly. The total floor-beam assembly depth is the combined depth of the supported floor member and the carried beam. For assemblies not including CLT floor above, the total assembly depth is the depth of the carried beam alone (see illustration).
  2. Ds-min and Ds-max values shown in the table only define minimum and maximum beam depths when considering joint rotation due to story drift but do not consider beam size requirements based on design loads. When joint rotation due to story drift need not be considered, refer to Table 3 for minimum allowable beam dimensions based on minimum fasteners edge distances.
  3. Table Ds-min and Ds-max depths values are rounded up and down, respectively, to the nearest 1 1/2" for nominal GLB depths.
  4. Table carried beams depths are based on floor depth ranges shown. To determine carried beam depths for floor depths not included in the table, refer to L-C-HSKPBEAM.

Code Reports & Compliance

Drawings

PDF DWG DXF RFA IFC SAT

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