Holding Down Bolts Example

Mott MacDonald

Project

Jo b n o .

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) 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; bolt;

Ft = 100.0 kN 100.0 kN

;

Try M20 (Grade 8.8); 8.8) ; bolts;  bolts;

Pt = 110.3 kN 110.3 kN ;

dnut = 16 mm 16 mm Check F t t  ≤    Pass - Bolt tension capacity ;  ;  ≤ P     t  t  ;  Pass

Pull-out resistance of concrete ;;

Overall length of bolts; bolts;

Lbolt = 600 mm 600 mm

;

Clear projection of bolt above nut; nut ;

Lproj = 50 mm 50 mm

;;;

Thickness of washer, baseplate & grout; grout;

twas = 3 mm ;

Depth of embedment; embedment;

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

tp = 30 mm 30 mm ;

tgr = 50 mm 50 mm

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

;

Depth of embedment selected; selected;

de = 452 mm 452 mm

Design spacing of bolts (c/c); (c/c);

Xccs = 300 mm 300 mm

Shear strength of concrete; concrete;

vc = 0.34 N/mm 0.34 N/mm2

Design pull-out resistance, per bolt; bolt;

Ptc = Aec × vc / 2 = 218.0 kN 218.0 kN Check F t t  ≤    Pass - Concrete pull-out resistance  ≤ P     tc  tc  ;  Pass

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

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