Rehabilitation and maintenance of buildings - 03 Karel Mikeš

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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