str654 - lecture 4b 2019

Sherif A. Mourad. Faculty of Engineering.

Cairo University

November 2020

STR654 1

STR654Special Topics in Steel Structures

Lecture 4b, October 15, 2019

Sherif A. Mourad

Professor of Steel Structures and Bridges

Faculty of Engineering,

Cairo University

TOPIC

Steel Erection Specifications. General.

Environmental constraints.

Safety.

Bridge inspector’s record.

Preliminary work.

Erection and assembly.

HSB connections.

Checklist.

Erection Tolerances


Cairo University

November 2020

STR654 2

TOPIC

Erection activities include:

Delivery of steel to site.

Handling.

Temporary storage.

Falsework.

Lifting assembly.

Completion of connections.

Installation of bearings/expansion.

ERECTION

Method depends on the type of structure, spans, equipment available & site condition.

Erection procedure shall consider stability under partial erection.

Erection of main elements shall ensure that they are not subject to overstressing.

Field splices and temporary supports.

Special cases.


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November 2020

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ENVIRONMENTAL

CONSTRAINTS

Removal of all temporary works.

Leave the site in a neat condition.

Clean-up of areas outside the site.

Berms, temporary piling, falsework.

Riverbanks, pits, …

SAFETY

Health and safety plan.

Hazard assessment, elimination and control.

Cranes and hoists.

Entrances, walkways, stairs and ladders.

Personal protective equipment.


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November 2020

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INSPECTION

RECORD Access for inspection.

As-built survey and camber record.

All shim levels.

Final elevations.

Settings for bearings.

Environmental conditions during measurements.

ERECTION

PROCEDURE

Traffic accommodation.

Substructure survey.

Access to work.

Sequence of operations.

Size and position of cranes.

Lifting devices and lifting options.


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November 2020

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ERECTION

PROCEDURE Falsework design.

Bolt torque method and sequence.

Securing position prior to grouting or bolting.

Grout procedure.

Falsework release.

Temporary access removal.

INSPECTOR

CHECKLIST Review & understand erection

procedure. Review falsework & traffic plan. Ensure complete survey of

substructure (independent survey). Alignment and level of bearings. Anchor bolt location. Bearing area on steel and concrete.


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November 2020

STR654 6

INSPECTOR

CHECKLIST

INSPECTOR

CHECKLISTSurface finish of concrete for

bearings.

Minor grinding/chipping required.

Leveling (shims).

Grouting for anchor bolts and base plates/bearing.

Grout temperature.


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November 2020

STR654 7

ERECTION

& ASSEMBLY Check elevations.

Special requirement for splices and field connections: 25% of the holes filled with bolts and 25% with erection pins before final bolting commences.

Serious misfits – remedy procedure.

Removal of shims, wedges, … so that the structure is carrying its own weight.

Check elevations after erection.

ERECTION

& ASSEMBLY

Expansion and bearing assemblies are properly offset.

Do not commence bolt tightening before the elevations are approved.

Steel to be left clean and free of mud, dust, oil, ...

Temporary works inside water channel.


Cairo University

November 2020

STR654 8

BOLTING

Rivets.

Ordinary bolts.

High Strength Bolts

Bearing type.

Friction type.

RIVETS


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November 2020

STR654 9

BOLTS

ORDINARY BOLTS

Components.

Strength.

Tolerance in hole size.


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November 2020

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HIGH STRENGTH

BOLTS

Components.

Strength.

Tolerance in hole size.

ERECTION

TOLERANCES

IN THE EGYPTIAN

CODE


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November 2020

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ERECTION

TOLERANCE

Overall dimensions of a building.

h or L =

±20mm for L ≤ 30 m

±20+0.25(L – 30) mm

for L>30 m

Maximum h or L is 50 mm

ERECTION

TOLERANCE

Level of top of floor slab. Floor

bearing on column.

h

± 5 mm


Cairo University

November 2020

STR654 12

ERECTION

TOLERANCEInclination of column in a multi-

story building; maximum deviation

for the vertical line between

adjacent floor slabs.

vh

0.003 h1

h1 = floor height under construction

ERECTION

TOLERANCE Inclination of column in a multi-story

building; maximum deviation for the vertical line through the intended location of the column base.

v1

0.0035(Σ h1)3/(n+2)

n = number of floors


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November 2020

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ERECTION

TOLERANCE

Inclination of column in a single-story residential building; maximum deviation for the vertical line.

vh1

0.0035 h

h = single-story floor height

ERECTION

TOLERANCEInclination of column in a portal

frame in an industrial building (not

supporting crane gantry), maximum

deviation for the vertical line.

vhp1 or vhp2 ≤ 0.010 h

(vhp1+vhp2)/2 ≤ 0.002h


Cairo University

November 2020

STR654 14

ERECTION

TOLERANCE

Unintended eccentricity of girder

bearing (e0).

e0 ≤ 5 mm

ERECTION

TOLERANCE

Distance between adjacent steel

columns at any level (ls).

± 15 mm


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November 2020

STR654 15

ERECTION

TOLERANCE

Distance between adjacent steel

girders at any level.

lt

± 20 mm

ERECTION

TOLERANCE

Positional deviation of a column base in relation to the column axis through the head of the column below (applied also in the case of indirect load transmission).

e2

5 mm in any direction


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November 2020

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ERECTION

TOLERANCE

Deviation in level of bearing

surfaces on steel columns (crane

girder level).

hc

+0 & – 10 mm

ERECTION

TOLERANCE

Positional deviation of bearing

surfaces.

e3

± 5 mm

str654 - lecture 4b 2019

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