New Civil Engineer research exposes challenges around designing steel to concrete connections.
Steel to concrete connection detailing is a tricky business. All too often multiple methods are needed to design the different elements in a single connection which increases the time taken for the connection’s design. This in turn affects an engineer’s productivity.
This might seem antiquated in a world of complex designs, BIM and integrated software, but these are the findings of a recent New Civil Engineer survey into connections and fixings. The survey asked 100 practising civil engineers to consider how they design steel to concrete connections.
Correctly designing this type of connection is a safety-critical part of a civil engineers’ role. Be it bridges or buildings, ensuring an effective and durable connection between steel and concrete is a consistent, crucial consideration for any design engineer.
In the survey, when it came to how the different elements - the anchor, baseplate, welds and stiffeners - were designed 54% of people said they used a combination of different software types, hand calculations and technical guidelines and approvals. Only 6% said they used a single software to design the connection.
“The lack of a single comprehensive piece of software to cover the design of connections in general (and steel to concrete in particular) makes the whole process complicated,” said one respondent. “Often, reactions have to be extracted from an FEA [finite element analysis] model and then two to three different methods need to be used to complete the design (I personally use two different pieces of software but have to supplement the outputs with hand calculations).
“This is not ideal and can lead to mistakes.”
The survey also found that although 45% of people said designing the connections took less than two hours, 33% of people said it took them two to four hours and more worryingly, 11% said it took between four and eight hours, and 10% said it took over eight hours.
“We need a design software to speed the design work,” said another respondent.
Speaking at the NCE100 Breakfast briefing Hilti product manager for technical software across Northern Europe Carlos Taborda says the lack of integrated software was holding engineers back.
“This need to use lots of methods to split up the connection means that there is not one reliable source to do the calculations and the change from one source to another affects their productivity,” said Taborda.
“This not only affects the engineer carrying out the task, it hinders them.”
Another aspect to the lack of integration he says is the overall optimisation of the connection. Around 30% specifically said optimisation was “difficult and time consuming with little time for iterations”. Another 43% said optimisation together with modelling connections with stiffeners and welds in finite element analysis took too much time and the baseplate rigidity was difficult to check.
So much is the problem – a whopping 79% of respondents said they would like an integrated design software - that Hilti has launched an updated version of its own anchor design software PROFIS Engineering. This will address the issues laid bare by the survey and design steel to concrete connections as a whole with inbuilt checks for steel baseplate rigidity as well as stiffeners and welds.
More details on PROFIS Engineering will be unveiled on newcivilengineer.com in March. In the meantime those looking for further information can visit www.hilti.co.uk/profisengineering.