Civil 211 - Structural Mechanics 2 - Sem 2 - 2005
Problem Sheet – Collation of Loads
Steel weighs 7850 kg/m3
1.
A two storey industrial laboratory building has simply supported steel beams at
3.2 metre centres supporting a timber floor. Each Beam spans 8 metres and can be
assumed to be a 360UB67 for self weight purposes. The floor comprises 300 by 50 sawn
timber floor joists at 400 cs carrying a 21 mm plywood floor. Cross battens to support
the ceiling are 75 by 50 at 400 cs. The following are superimposed dead loads applied to
the floor –
Partitions 0.4 kN/m2
Ceiling 23 kg/m2
Services 19 kg/m2
Live Load to the suspended Floor of the Laboratory Building (from NZS 4203) is 3.5 kPa
From the above information determine the uniformly distributed design load on the steel
beam under the ultimate load combination of 1.2G & 1.5Q and under the serviceability
condition G & Q
2.
Two deep plate girder “I” beams in an industrial support structure are required to
carry four point loads from a papermaking machine. Steel platforms (basic live load 2
kPa) are also supported by the beam. The beams are made of three plates (top & bottom
flanges are 250 by 16 mm flat and the web plate is 600 deep by 12mm wide), span 6.3
metres with each carrying two machinery point loads at third points and carrying an
equivalent of 1.8 metres width of maintenance platform. Dead loads for the maintenance
platform can be assumed to be 65 kg/m2. The total self weight of the machine (4 legs) is
17.6 tonne and the additional equivalent dynamic live load at worst overloaded condition
is 3.4 tonne. Each leg can be assumed to carry 28% of these loads (assuming some
uneven redistribution) and two are applied at third points of the simply supported beam.
From the above information determine the Design Loads on the Beam under the ultimate
load combination 1.2G & 1.5Q where the self weight of the machine can be assumed as
G and its equivalent dynamic live load as Q. Sketch your result.
3.
A Client requires a canopy along the length of a supermarket to provide a covered
2.4m high walkway for customers. The canopy can be cantilevered off the main building
structure where there are structural columns at 6.4 m centres. The canopy extends 3.2
metres from the side of the building and carries metal roofing (10 kg/m2) supported by
RSC (150PFC – 17.7 kg/m) purlins spanning between the cantilevers at 800 mm cs. For
assessment of load purposes the cantilever beam can be assumed as 310UB40. Vertical
live load on the canopy is 0.25 kPa and uplift under severe wind conditions could be 2.8
kPa. From the above information determine the Design Loads on the cantilever Beam
under both the ultimate load combinations 1.2G & 1.5Q and 0.9G & W (uplift). Sketch
your result.
4.
A simply supported steel lintel beam over a window at the top floor in a $3.2
million residence in Mount Albert is required to be designed. The Lintel carries the
equivalent of 4.2 metres of roof (assuming a 600 mm overhang for eaves) and spans 7
metres. The roof is concrete tiles on 75 by 50 battens at 300 cs on 12 mm plywood. 100
by 50 purlins at 600 cs support the plywood and span between timber roof trusses at 1200
cs. The roof is to be designed for a basic live load of 0.25 kPa and an uplift wind force of
1.8 kPa. Dead loads on the structure comprise
Roofing 50 kg/m2
75 by 50 timber 1.6 kg/m
Plywood 6.5 kg/m2
100 by 50 timber 2.1 kg/m
Ceiling 15 kg/m2
Services 8 kg/m2
Equivalent Trusses 24 kg/m2
Assuming the beam is a 250UB31, calculate the uniformly distributed load on the lintel
under the ultimate design load condition 1.2G & 1.5Q and 0.9G & Wind (Uplift). Also
determine the load under G & Q for Serviceability calculations
5.
Two rooms in a school are divided by a timber frame wall 3.3 m high. The Wall
is to be removed and replaced with a high level steel beam spanning 6.3 m which is to
support a heavy sliding partition. The partition which is supported solely off the steel
beam weighs 75 kg/m2 and can be assumed as contributing to the G portion of the load.
The beam also carries 3.8 metres of roof structure. Calculate the uniformly distributed
load on the beam when the partition is fully closed under the serviceability condition of G
& Q assuming the following –
Beam say 410UB54
Roofing 10 kg/m2
100 by 50 timber purlins @ 900 cs 1.8 kg/m2
75 by 50 timber ceiling battens @ 600 cs 2.6 kg/m2
Ceiling 13 kg/m2
Services 4 kg/m2
Equivalent Trusses 22 kg/m2
Roof Live Load 0.25 kN/m2
Answers
1. UDL (ULT 1.2G & 1.5Q) = 21.9 kN/m – (SERV – G & Q) = 15.5 kN/m
2. UDL (ULT) = 8.2 kN/m plus Two ULT Pt Loads 73.4 kN each
3. UDL (ULT 1.2G & 1.5Q) = 0.5 kN/m plus ULT Pt Loads at each end of
Cantilever of 2 kN and three intermediate point loads (@ 800 cs) of 3.9 kN
Under Wind (0.9G & W) – UDL = 0.4 kN/m downwards, plus Pt Loads of 10.5
kN upwards at each end of the canopy and three at 20.9 kN upwards @ 800 cs
internally
4. UDL (ULT 1.2G & 1.5Q) = 7.7 kN/m
UDL (ULT 0.9G & W) = 3.0 kN/m upwards
UDL (SERV G & Q) = 6.2 kN/m
5. UDL ( SERV G & Q) = 6.4 kN/m
Civil 211 – STRUCTURAL MECHANICS 2
Table of Suggested Self Weights of Common Building Materials
Note: for any particular cladding or material Designers should check with the
Supplier or Manufacturer for actual weights
Area
Roof :
Walls :
Floors :
Timber : Dry,
gauged
Type
Metal Roofing
Aluminium Roofing
Decramastic Tiles
Concrete Tiles
8 mm Plaster Ceiling Tiles
13 mm Plaster Ceiling Tiles
10 mm Gib Board Ceiling
13 mm Gib Board Ceiling
Roof Trusses
100 mm timber stud wall
with Gib both sides
70 mm cavity brick wall
incl timber framing & Gib
6 mm Glass incl Frames
200 masonry all cells filled
Fibre Cement Panels –
9 mm
6 mm
10 mm Gib (Braceline)
13 mm Gib (Noiseline)
16 mm Gib (Fyreline)
150 mm concrete
20 mm Particle Board
25 mm dry timber
Ply Flooring –
15 mm
17 mm
19 mm
21 mm
25 mm
Joists – at 450 cs / 600 cs
100 * 50
150 * 50
200 * 50
250 * 50
300 * 50
100 * 50
150 * 50
200 * 50
250 * 50
300 * 50
Value
10 kg/m2
4 kg/m2
10 kg/m2
50 kg/m2
9 kg/m2
14 kg/m2
7.0 kg/m2
8.5 kg/m2
10 kg/m
31 kg/m2
150 kg/m2
20 kg/m2
460 kg/m2
17 kg/m2
11 kg/m2
8.5 kg/m2
12.7 kg/m2
13.7 kg/m2
360 kg/m2
14 kg/m2
15 kg/m2
8.3 kg/m2
9.2 kg/m2
10.5 kg/m2
11.6 kg/m2
13.5 kg/m2
4.7 / 3.5 kg/m2
7.1 / 5.3 kg/m2
9.6 / 7.2 kg/m2
12.2 / 9.2 kg/m2
14.7 / 11.0 kg/m2
2.1 kg/m
3.2 kg/m
4.3 kg/m
5.5 kg/m
6.6 kg/m