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Feature
thestructuralengineer.org Innovation in structural engineering - the art of the possible
Innovation in practice

previously studied and explored the material
were engaged, in particular Patrick Jennings
(independent consultant) and Paul Nedwell
(Manchester University). While they had very
good experience in using the material, the
applications previously explored were some
way from the highly engineered structure that
was being developed for the SNFCC.

Initial analysis
As Expedition needed to deliver a production
process as well as a design solution,
understanding the ferrocement production
processes was as important as getting an
understanding of its mechanical and chemical
properties. The team began by developing
some small samples of ferrocement to inform
their thinking on production and use.
Some published guidance on the use of N
Figure 5
ferrocement was available. Eurocode 2 Column heads
4
provides ‘first principles’ guidance that is

helpful for the design of ferrocement, which is calculations dramatically reduced the modelling. A similar process was followed
unusually thin reinforced concrete. However, evidence burden for the basic mechanics of for the column head assemblies (Figure 5).
EC2 is limited in its detailed guidance since the material, but calculations for the material This computational modelling saved time and
ferrocement falls outside the geometrical in a specific configuration money by reducing significantly the real-world

limits for which the code was developed. (ribbed, two-way curving shells) were still testing required.
To extend the Eurocode guidance, the very onerous.
team reviewed the ferrocement design The structural engineering team applied Initial samples – product and process
guides, academic studies and took advice these typical calculations to develop initial Having put in the theoretical ground work
from the ferrocement specialists. Together, design solutions describing the solution at to develop the confidence that ferrocement

these provided the team with the confidence a high level. The results from these initial would be an appropriate solution, initial virtual
that some of the first-principles rules for calculations suggested that, in theory, the and timber three-dimensional (3D) models

building with standard reinforced concrete ferrocement canopy solution would work. of the canopy were created to explore
could be extended to cover the context of the structure more thoroughly. Samples
ferrocement. The ability to use these common Independent analysis of ferrocement were also produced so
These initial solutions were then tested and that the team was able to develop a better
validated. Finite-element analysis was used understanding of the material.
throughout the process. Independent review Expedition had also taken the technical
"WITH ME JUMPING and testing of key critical scenarios for the lead for the development of the on-site
ON THAT THIN PIECE ferrocement was undertaken by ANSYS, production process and worked together
with a contractor to create a production
using sophisticated analyses such as non-
OF FERROCEMENT linear finite-element analysis with crack line and early samples of the panels. Early

WHICH TRADITIONAL panel production was relatively slow, but as
CONSTRUCTION INDUSTRY the precast team learnt about the process,
WISDOM SAID WOULD BE they became more efficient. Process

UNFEASIBLY FRAGILE, THE improvements were found on site, making

STRENGTH OF A SHEET the process more efficient. Subsequently, an
OF FERROCEMENT COULD automated solution was proposed, but this

has not yet made it off the sketch pad.
BE COMMUNICATED FAR
BETTER THAN ANY OTHER Initial tests
KIND OF EXPLANATION. Once the process of precasting the
UNTIL WE HAD THAT, WE panels had been developed, indicative
DIDN’T HAVE ANY SIMPLE ferrocement panels became available for
WAY TO COMMUNICATE IT. testing. Initial loading and impact tests
IT WAS FUNDAMENTAL TO involved members of the team jumping on
ferrocement panels (Figure 6), just 15mm
PERSUADING PEOPLE THAT thick, and then striking the panels with a 5kg
THIS MATERIAL WORKS" N hammer. These tests, while not scientific,
Figure 6

Dr Pete Winslow, Engineer ‘Pete jump test’ – key element of gave the design team increased confidence

building design team’s confidence

in the design process and were fundamental
TheStructuralEngineer | January 2017 19
한국건축구조기술사회지 Journal of The Korea Structural Engineers Association 51
TSE61_14-21 Feature-Innovation in Structural Engineering.indd 19 15/12/2016 10:44