17 Feb 88 ISE
INSTITUTION OF STRUCTURAL ENGINEERS, NORTH THAMES BRANCH
JUNIOR MEMBERS DESIGN AND BUILD COMPETITION - FOR STUDENT & GRADUATE MEMBERS
of the NORTH THAMES BRANCH
A first prize of £50 and a second prize of £25 are offered by the North Thames Branch of the
Institution of Structural Engineers for the two best entries in the 1988 Junior Members
Competition. This is open to all Student and Graduate members of the Institution in the
Branch area. Note that all students in relevant full-time education (Civil and Structural
Engineering courses) are eligible for free Student membership of the Institution for the
duration of their courses.
Specification:
Design and construct a model tower to support a rectangular water tank 150 mm long, 75 mm
wide and 75 mm high weighing 450 g. at a height not less than 300 mm above the ground
using unreinforced spaghetti as the structural material. Any form of construction ranging from
lattice tower to solid core is allowed. The tower may be assembled using any type of adhesive,
clamp or lashing, provided these do not contribute additional reinforcement.
The design 3-sec gust wind speed (corresponding to VS = S1S2S3V in the UK code of practice
for wind loads, CP3 ChV pt2) shall be taken as 15 m/s. The tower shall be designed with a
safety factor of 1.5 on the design wind loads calculated from CP3 ChV pt2 and a safety factor
of 1.0 (unity) on the deadweight loads (weight of tank).
The only restrictions are that the tower must fit on a base board 250 mm x 350 mm and must
support a 150 mm x 75 mm metal plate, both of which will be supplied to participants. The
model tank will not be provided since, for fairness in testing. the same model tank will be used
for all participants and will be fixed magnetically to the metal plate. For the purposes of design
calculation and testing the scale of the model should be taken as 1/50 and the tower should
be considered to be on flat ground in a suburban environment (terrain category 3 in CP3 ChV
pt2). (If a lattice construction is used, participants may also care to consider the provisions of
BS8100.)
Testing:
During the competition meeting, starting at 7 pm on Wednesday 17 February 1988 at the
Building Research Establishment, Garston. Watford, the model scale towers will be prooftested in the boundary layer wind tunnel. Participants are required to attend this meeting. The
ideal tower will withstand the design loading without showing any signs of distress but will fail
at the design loading x the safety factor. Points will be awarded for performance as follows:
failure below the design wind load - no points. Failure at design load x safety factor maximum points. Failure above design load x twice safety factor - no points. Additional points
will be awarded by the judges for economy and elegance which. as all Institution members are
aware, are the essence of Structural Engineering.
Entries:
Applications to enter this competition should be sent to: Dr N J Cook. Structural Design
Division, Building Research Establishment, Garston, Watford WD2 7JR.
26 Feb 88
Going ... going ...
SPAGHETTI was tested to destruction at the Building Research Station in Garston last week.
The pasta was put through its paces in the wind tunnel rather than the canteen after student
structural engineers were told to design and build a 12" high water tower out of spaghetti as
part of an exercise.
The winners were a team from Alan Baxter Associates of London.
“They had to design a tower with elegance and economy It had to collapse at the required
windspeed”, said Dr Nick Cook head of the wind engineering section at the Department of
Environment’s Building Research Establishment.
Students from the North Thames branch of the Institute of Structural Engineers had to build a
pasta tower which could withstand winds of over 60 mph.
The towers were required to collapse at around 60 mph. If they disintegrated before or after
this speed, the team lost marks.
“It was an exercise in real engineering,” said Dr Cook. “They had to build a structure which
had a safety factor of one. But if it was any stronger then a full scale structure would be too
expensive to build,” he added.
Make-and-break competition
Structural engineers are once again invited to enter the annual Leeds University design makeand-break competition. This year, the competition concerns the design of a deck support
girder for a cable-stayed bridge. The bridge is required to carry the four deck units (mass
250g/deck unit), and a proof-loaded vehicle (mass 1.667kg).
The deck support girder is to be made from spaghetti, tinned copper wire or cane, and will be
costed on the basis of the weight of the deck support girder in grams, multiplied by £1000/g
for spaghetti, £600/g for tinned copper wire, or £1200/g for cane. Any suitable jointing
technique may be used including adhesives, solder, tape or cotton.
At the test session on the afternoon of Friday 16 December some 60 entries will be tested. Not
only should there be some spectacular disasters, but also some really creative designs. The
lowest cost deck support girder to permit the proof-loaded vehicle to be slowly pulled across
will be considered the winner and awarded a suitably engraved trophy.
Donald Datton, the organiser, predicts that the winner will have a design that will show a 50%
saying over the mean of other entries. He believes that there will also be much more
expensive designs that fail under load.
For those prepared to accept the challenge, full details can he obtained by sending a stamped
addressed envelope to EurIng. Donald Dalton, MICE, MIMechE, Department of Civil
Engineering, University of Leeds, Leeds L52 9JT.
1 Mar 88
Structural spaghetti competitions
Nine teams of students and graduate members from the North Thames Branch of the
Institution of Structural Engineers entered a competition organised in conjunction with BRE to
design and construct a model tower out of spaghetti. The 300mm-high towers, capable of
holding a water tower of 45g and designed to withstand a wind speed of 34 mph plus a safety
factor of 1.5, were tested in the BRE’s wind tunnel. Highest marks were awarded to those
whose model disintegrated closest to the design specification, points were also awarded for
elegance and economy. The eventual winners were Ralph Perera, Helen lgoe, Jayne Hegget
and lan Prentice from Alan Baxter Associates of London ECI.
The finals of the Schools’ Spaghetti Bridge Competition were held at Leeds University on
Friday 5 February 1988. Entrants had to produce a bridge to span a gap of 300mm and
capable of supporting a 1kg bag of sugar, using as little spaghetti as possible. 150 entries
were received from schools all over the country.
A wide variety of ideas were included in the designs, which used from 300g to less than about
10g of spaghetti. Teachers and pupils gained an understanding of the nature of structural
design. Achieving the objective is of course the first priority, but being able to do it with 1/30
of the materials of someone else is an impressive saying!
The 14 lightest successful designs (all under 13.5g) were selected, and the designers invited
to bring their bridges to Leeds for the finals. A display was mounted showing the different
entries.
The spaghetti bridges wore tested to destruction to see their mode of failure and reserve of
strength. There were book tokens for the highest strength/weight ratio. However, the main
prizes were for the lightest designs to support the 1kg bag of sugar.
Professor Michael Horne, OBE, FRS, FEng, Past President, presented the prizes. The outright
winning structure was a spaghetti bridge weighing a mere 9.5g designed and built by Carl
Waugh, Martin Gore and David O'Neil from St. John Rigby VI Form College in Wigan. Robert
Gore from St. Paul’s School London was the winner in the under 16s, with a bridge only
marginally heavier at 10.8g.
The main prizes, provided by Buitoni were £750 for the school and £75 for each of the
designers. All finalists received copies of books provided by the Institution by Professor James
Gordon, as well as a certificate and a bright Buitoni apron.
There was also a special prize for 8-year old James Davits of Moor First School, Biddulph,
Staffs., for his 18.49 g bridge, which was the lightest design from an under 12.