UK office of IDEA StatiCa s.r.o.
Email: info@ideastatica.uk
Phone: +44 (0) 20 3579 9397

About IDEA StatiCa

We develop software for structural engineers and detailers. Our development team researches, tests, and applies new methods of analyzing the behaviour of structures and their members. Based on this, we created IDEA StatiCa – software that enables engineers to work faster, evaluate requirements of the national code thoroughly, and use the optimal amount of material. For us, creating software is a way to contribute to making every new construction around the world safer and cheaper.

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Braithwaite Steel Tank: Hot pressed Steel Sectional Water Tank

Braithwaite Steel Tank

Braithwaite Steel Tank: Hot pressed Steel Sectional Water Tank 

Explore the remarkable Braithwaite Steel Tank, a hot-pressed steel sectional water tank, showcasing engineering innovation and structural excellence. Discover its design, construction, and vital role in ensuring reliable water supply in the UK. This blog unveils the features that make it a standout example of structural engineering, powered by IDEA StatiCa’s advanced software.

Structural Science Ltd, in cooperation with Braithwaite Engineers, is implementing IDEA StatiCa Connection software to continually research and design bespoke connections in Braithwaite Steel Tanks. With over 125 years of experience in steel sectional water tank design and manufacturing, they have installed tanks worldwide.


In the construction of sectional steel pressed tanks, a variety of connections is used, and in this short case study written by Dale Price, a structural engineer at Structural Science Ltd., the stay connection is discussed which supports the horizontal hydrostatic water pressures exerted on the walls of the Braithwaite Steel Tank.

About the connection that has been tested

As you can see in Figure 1, the Braithwaite Steel Tank steel bolted stay connection or cleats consists of a thin baseplate with a welded fin plate connecting the angle stay between the base and walls or the wall corners of the tank and can be subjected to 75 KN design tension force in normal cases.


Historically, Braithwaite Steel Tank design is normally undertaken by hand calculations, and verification of connections has been confirmed by preparing expensive full-scale laboratory testing of components and testing full-scale site mock-ups of tanks.

Figure 1

Figure 2 shows recent full-scale testing of a tank where a stay is connected to strain gauges which continually monitor the load on tank stays during water filling and long static water tests.

Back in the laboratory, Figure 3 shows the stay connection being proof tested to code requirements (and of course other strength and failure tests not shown here).

Figure 2
Figure 3

The stay connection has been analyzed with IDEA StatiCa, and the below screen shots summaries the procedure:


Figure 4, describes the overall arrangement of the connection with bolts and welds with 75 kN design axial load to the stays.

Figure 5, highlights the equivalent stress plots indicating the areas of highly stressed components and

Figure 6, indicates developed plastic strains on the baseplate.

                           Figure 4                                                                   Figure 5                                                                 Figure 6

Of course, except from pure analysis results, more importantly, IDEA StatiCa provides the overall EC/AISC checks for all elements, as shown in Fig.7, giving us very clear Pass/Fail results (Fig.8)

Figure 7
Figure 8

In conclusion, the Braithwaite Steel Tank connection behavior and load correlation between full-scale/laboratory testing and CBFEM software was very good, and therefore, the full-scale testing program confirmed the validity and accuracy of the IDEA StatiCa software for Braithwaite Steel Tank connection design. In general, future bespoke Braithwaite Steel Tank connection designs can now quickly be realized using this software without implementing and planning costly and long-period testing programs.


The software is currently being used to rationalize and develop better Braithwaite Steel Tank connection designs with benefit savings in cost and manufacturing processes. Other difficult bespoke Braithwaite Steel Tank connections related to the tank design are now being investigated using the IDEA StatiCa software.

Fig.9 – Deformed shape representation help the engineer to have a better understanding of the connection’s behavior

Summarizing, some of the key benefits of using IDEA StatiCa are:

  • Reduce the period of the desk-based and repetitive connection design work.
  • The ability to model of all the components of the connection in one design, i.e. weld, bolts, plates, and section in one assembly, and understand the better interaction between individual components and compare this against breaking up the connection into individual design components.
  • Continually investigate, develop, and research old and new bespoke connections without planning long and expensive full-scale test programs to verify connection designs.
  • Improve existing connections by rationalising plate or section sizes, vary configurations for cost manufacture, and verify increased design forces from the normal design for example earthquake forces subjected to tank walls.
  • The full-scale testing has provided confidence in the implementation of designing such connections using finite elements and specifically IDEA StatiCa Steel software which is based on the new CBFEM method.
  • Switch designs with updated different country connection standards.
About Braithwaite Engineers:

Braithwaite is an international company with a reputation for technical excellence founded on more than 125 years of experience in bridges and storage tanks. The name Braithwaite is synonymous with a comprehensive range of liquid storage tanks and ancillary products. Our range of Steel and GRP modular tanks has gained an enviable reputation worldwide.



About Structural Science Ltd:

Structural Science a small international structural engineering consultancy based in the South West of England and provide engineering consultancy to Braithwaite and Engineering Consultancies.  With over 30 years of experience in tall buildings, long span structures, stadiums, airports, and special structures.



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