Solution to Assignment 3 - Checking Scaffold Falsework
(a) Calculation of Wind Moment
Vd 25 m/s (Bahrain Wind Code)
q=(Vd/40.4)2 = (30/40.4)2= 0.383 kPa
A(scafold)=n*Overall Area = 0.04*(1.5*7.5)*8 3.600 m2
A(toeboard) = 0.2*1.5 0.300 m2
w(scaffold)=Cf*q*A = 1.3*0.551*3.6 1.792 kN per row
w(toe board)=*Cf*q*A = 2.0*0.551*0.300 0.230 kN per row
Wind Moment = w*h =2.581*7.5/2 +0.331*(7.5+0.2/2) 8.467 kN-m per row
(b) Max Leg Load
Total Loading Intensity = 6.0 kPa*1.5 m 9 kN/m
Calculation of Leg Load Total
udl= 9 kN/m Total Vertical Load =9*9.1 = 81.9 kN
Moment= 8.467 kN-m
Member A B C D E F G H
li (m) 4.55 3.25 1.95 0.65 0.65 1.95 3.25 4.55
li2 (m) 20.703 10.563 3.803 0.423 0.423 3.803 10.563 20.703 70.98
pi 0.292 0.149 0.054 0.01 0.01 0.05 0.149 0.292 1.000
Induced Vert. Load Fi (kN) -0.54 -0.39 -0.23 -0.08 0.08 0.23 0.39 0.54
Vertical due to udl Vi (kN) 5.85 11.70 11.70 11.70 11.70 11.70 11.70 5.85 81.900 kN
Total leg load (kN) 5.31 11.31 11.47 11.62 11.78 11.93 12.09 6.39
Max Leg Load 12.09 kN
Lift height 1.25 m
Leg Loading Capacity
(Assume "USED" conidtion) <47 kN OK from Table 1
None of Verticals are negative or under tension
(c) Calculation of Diagonal Braces
Total Wind Load =2.581 + 0.331= 2.022 kN
Coupler Capacity 6.25 kN (BS1139)
Angle of Diagonal Inclination =tan-1(1.25/1.3) = 43.88 degrees
Therefore nos. of diagonal required = 2.911/ (6.25 * cos 43.88 degrees)
= 0.45
Provide One(1) No. of Diagonal Brace per row
One Diagonal Brace for each row of Scaffold with swivel couplers fixed at each level
for each row of scaffold structure (Or alternatively, two for every second row)
(d) Calculate the Factor of Safety vs Overturning
O/T Moment = 2.581*7.5/2 Since there are two edge boards
+2*0.331*(7.5+0.2/2) = 10.213 kN-m per row exposed to lateral wind
UDL due to Dead Load for an empty workinmg platdorm = 1 kPa *1.5 m = 1.5 kN/m
R/S Moment = 1.5*(9.1) *
(9.1)/2 62.108 kN-m (7 bays each 1.3 m wide)
Factor of Safety vs Overturning = 62.108/14.706 = 6.08 > 1.2 OK
No Kentledge is required
(e) Soil Bearing Pressure 150 x 150 Pmax = 12.26 kN
Base Plate to Scaffold Leg 0.15m Base Plate Sole Plate Thickness
Sole Plate Thickness 0.05 m 50 mm
Sole Plate width (Assume
150x150 base) 0.3 m
Sole Plate Loaded Length (load
spreading at 1 on 2) = 2*2*0.50
+ 0.15 = 0.35 m 100 150 100
Base Area = 0.3 m x 0.35 m 0.105 m2
Soil Bearing Pressure =
12.26/0.105 115.12 kPa
Assessment Plan Key Skills Criteria Marks
Communication, IT and Numeracy
F1 Accuracy of Calculations & Sketching 5.0
Analytical & Problem Solving
F5 Loading Determinination & Structural Analysis 5.0
Responsibility & Autonomy Check Points, Quote BS Materials.. Code of
P2 Practice.etc. 2.5
Total 12.5
Total Load (Per leg)
Dead Load + Live Load + Transferred Load = Total Load
Dead Load
This load does not include the weight of workers, extra materials, or other similar variables.
Dead load is calculated using the following formula:
Sum1 + Sum2 = Dead Load
Sum
This is-1the weight of all the components directly on each leg that has a screwjack.
This includes materials such as vertical posts (standards). screwjacks, headers (if applicable), support
Sum-2
This is 1/4 of the weight all components on the bays attached to the selected leg's bay such as planks
Live Load
Live Load is the additional load on the leg when the scaffold is in use.
This includes workers, work materials, etc but does not include the scaffold materials
Live load is calculated using the following formula:
Usable Deck Area x Unit Live Load = Live Load
Usable Deck Area
This is 1/4 of the area of the Usable Deck levels as defined by the user in the Leg Load Table dialog.
Unit Live Load
This is Unit Live Load as defined by the user in the Leg Load Table dialog.
Transferred Load
Transferred Load is the additional load on the leg for adjacent suspended legs/bay. Suspended legs a
er similar variables.
aders (if applicable), supported ladder runs, etc.
cted leg's bay such as planks, horizontals, braces, etc.
old materials
the Leg Load Table dialog.
d legs/bay. Suspended legs are legs without screwjacks. Load will be transferred for up to 1 and 1/2 bays.
