1. Rehabilitation and maintenance of buildings - 03
Karel Mikeš

2. SAHC - SA5 Steel structures
2010
Contents
Properties of material
Failures of steel structures
Types of refurbishment
Methods of reliability verification
Basis of members design of steel structures
Basis of joint design
Assessment of steel structures
Strengthening of members
Strengthening and refurbishment of structures
Refurbishment of masonry structures using steelwork
Seismic upgrading using steel structure
T.Vraný, CTU in Prague

3. SAHC - SA5 Steel structures
2010
Connections
Bolted
Welded
Riveted (history)
Realised:
In shop
On site
Calculation:
on resistance
on calculated internal forces
T.Vraný, CTU in Prague

4. Connections Bolted connections
SAHC - SA5 Steel structures
2010
Connections Bolted connections
Types:
According to static behaviour:
Normal (no preloading)
Slip‑resistant (controlled tightening)
According to loading:
Shear
Tension
T.Vraný, CTU in Prague

5. Bolted connections Shear loading
SAHC - SA5 Steel structures
2010
Bolted connections Shear loading
Common bolts:
shear
bearing
Slip‑resistant bolts:
slip
T.Vraný, CTU in Prague

6. Bolted connections Shear resistance
SAHC - SA5 Steel structures
2010
Bolted connections Shear resistance
for bolt grades 4.8, 5.8, 10.9
for other bolt grades
As Core area of cross section of bolt
fub Ultimate strength of bolt
i Number of shear planes
gM2 =1,25
T.Vraný, CTU in Prague

7. Bolted connections Bearing resistance
SAHC - SA5 Steel structures
2010
Bolted connections Bearing resistance
Effect of bolt pitches
t Minimum thickness in one direction
d Diameter of bolt
d0 Diameter of hole
fub Strength of bolt
fu Strength of material
T.Vraný, CTU in Prague

8. Bolted connections Resistance of slip-resistant bolts
SAHC - SA5 Steel structures
2010
Bolted connections Resistance of slip-resistant bolts
Slip resistance
prestressing force
As Core area of cross section of bolt
fub Ultimate strength of bolt
n Number of friction planes
m friction coefficient ... 0,2 to 0,5
T.Vraný, CTU in Prague

9. Bolted connections Bolts loaded in tension
SAHC - SA5 Steel structures
2010
Bolted connections Bolts loaded in tension
Resistance in tension
The same resistance for common and preloaded bolts
T.Vraný, CTU in Prague

10. SAHC - SA5 Steel structures
2010
Welded connections
Fillet welds
Butt welds
fully supply basic material
Welds = rigid connections (no slip)
T.Vraný, CTU in Prague

11. Welded connections Fillet welds
SAHC - SA5 Steel structures
2010
Welded connections Fillet welds
a effective throat thickness of the fillet weld
┴ direct stresses perpendicular to the throat
┴ shear stresses perpendicular to the axis of weld
║ shear stresses parallel to the axis of weld
║ direct stresses parallel to the axis of weld (neglected)
T.Vraný, CTU in Prague

12. Welded connections Check of fillet weld
SAHC - SA5 Steel structures
2010
Welded connections Check of fillet weld
bw correlation factor
depends of steel grade
T.Vraný, CTU in Prague

13. Welded connections Two fillet welds in parallel shear
SAHC - SA5 Steel structures
2010
Welded connections Two fillet welds in parallel shear
T.Vraný, CTU in Prague

14. Welded connections Connection of cantilever
SAHC - SA5 Steel structures
2010
Welded connections Connection of cantilever
V – transferred by web:
M – transferred by whole weld cross-section: 
Point 1: tII, t┴, s┴
Point 2: t┴, s┴
T.Vraný, CTU in Prague

15. Welded connections Flange-to-web weld
SAHC - SA5 Steel structures
2010
Welded connections Flange-to-web weld
Longitudinal shear flow Vℓ:
T.Vraný, CTU in Prague

16. SAHC - SA5 Steel structures
2010
Riveting
Assembly
Heated to white heat
Pneumatic hammer (clamping rivet’s length max. s = 4,5 d)
Function (after cooling)
Fully filled hole
Before riveting diameter is by 1 mm less then hole diameter
Prestressing connected sheets
Material
Rivet from steel with lower strength than basic material (when they are exchanged can be cut off)
Head
Half spherical
(Countersink)
T.Vraný, CTU in Prague

17. SAHC - SA5 Steel structures
2010
Riveting
Supply at the refurbishment:
Additional rivets or bigger diameter
Bolts – slip resistant connection, „retro“ heads of bolts
Bolts injected by epoxy
Riveting is history
Exhibition on 3rd floor of Eiffel's tower
T.Vraný, CTU in Prague

18. Riveted connections - Resistance
SAHC - SA5 Steel structures
2010
Riveted connections - Resistance
Shear
Bearing ... as for bolts
Tension
T.Vraný, CTU in Prague