Hinged Base Plates: M24 Anchor Bolts, C35 Grout, The Simple Column Footing

Hinged column bases pin steel columns to concrete foundations — they transfer vertical load and shear, but no moment. Below is data from an actual hinged base detail.

---

Basic Specs

 

Item	Value
Base type	Hinged (pinned) base
Anchor bolts	M24, Q235B
Anchor quantity	4 per column
Anchor length	~900 mm (600 mm straight + 100 mm hook)
Base plate	Steel plate under column
Nuts	Double nuts
Grout	C35 fine stone concrete
Protection boot	C20 fine stone concrete, 50 mm each side

---

Construction Details

The hinged base consists of:

Base plate: steel plate welded to column bottom

Anchor bolts: 4×M24 Q235B, embedded in foundation

Double nuts: top and bottom nuts lock column to plate

Grout layer: C35 fine concrete between plate and foundation

Concrete boot: C20 concrete 50 mm around column base

---

How It Works

The hinged base works as a pin:

Vertical load: column compression goes through plate to foundation

Shear: friction between plate and grout + anchor bolts

No moment: plate can rotate slightly under lateral load

Alignment: bolts fix column position on foundation

---

Advantages

Simple design — no stiffeners, just plate + bolts

Easy to install — plate sets on bolts, nuts tightened

No moment transfer — hinge avoids foundation moment

C35 grout level — grout layer adjusts for foundation unevenness

C20 boot protects — concrete boot covers base from moisture

---

Disadvantages / Limitations

No moment resistance — hinge can't take lateral moment

Anchor bolts yield in shear — bolts carry shear, can bend

Grout quality critical — weak grout = settlement

Foundation alignment — bolt positions must match plate holes

Boot cracks over time — C20 boot can crack under load

---

Typical Applications

Portal frame columns — hinged bases for light frames

Warehouse columns — single-story building columns

Roof truss supports — truss bearing on hinged base

Temporary structures — fast erect, simple base

Wind column bases — wind columns pinned at base

---

Installation Notes

Anchor bolts M24 set in foundation before concrete pour

Base plate lifted over bolts, leveled on shim packs

Double nuts tightened after alignment

C35 fine concrete grouted under plate

C20 concrete boot cast around column base, 50 mm overhang

---

Hinged steel column base — M24 Q235B anchor bolts, 4 per column, double nuts, C35 grout layer, C20 concrete boot 50 mm overhang, pinned base for portal frame and warehouse columns.

**WhatsApp**: +86‑13889862778, +86‑18242444407
**Email**: eddie@zdsteels.com, wells@zdsteels.com