Holding Down Bolts Example 6324q

Mott MacDonald

Project

Job no.

Calcs for

Start page no./Revision

1

1 Atlantic Quay Broomielaw

Calcs by

Glasgow G2 8JB, UK

M

Calcs date

Checked by

Checked date

Approved by

Approved date

27/10/2016

L_proj (Clear projection of bolt above nut)

t_was (Washer thickness)

t_p (Base plate thickness)

t_gr (Thickness of bedding)

Concrete

L_bolt (Overall length of bolts)

PULL-OUT CAPACITY OF HOLDING DOWN BOLTS TEDDS calculation version 1.0.01

These calculations assume that there is no coexistent shear in the holding-down bolts. Tension capacity of bolts ;

Maximum tension force per bolt;

Ft = 100.0 kN

;

Try M20 (Grade 8.8); bolts;

Pt = 110.3 kN ;

dnut = 16 mm Check Ft ≤ Pt ; - Bolt tension capacity;

Pull-out resistance of concrete ;;

Overall length of bolts;

Lbolt = 600 mm

;

Clear projection of bolt above nut;

Lproj = 50 mm

Thickness of washer, baseplate & grout;

twas = 3 mm ;

Depth of embedment;

de = Lbolt - Lproj - dnut - twas - tp - tgr = 452 mm

;;;

tp = 30 mm ;

tgr = 50 mm

From BCSA HDBolts document, effective conical surface area; for two bolts; Aec = 12825.9 cm2

;

Depth of embedment selected;

de = 452 mm

Design spacing of bolts (c/c);

Xccs = 300 mm

Shear strength of concrete;

vc = 0.34 N/mm2

Design pull-out resistance, per bolt;

Ptc = Aec × vc / 2 = 218.0 kN Check Ft ≤ Ptc ; - Concrete pull-out resistance

Bolts require adequate anchorage by suitably sized washer plates or equivalent under the bolt heads. BS 5950: Part 1: 2000: Sections 4.13 & 6.6 'Holding down systems for steel stanchions' BCSA / Constrado 1980

;