José Vicente Rajadell is a mechanical engineer specialising in structural analysis, machine design and teaching about structures, an area in which he has been a lecturer at the Universitat Jaume I (2003-2017), collaborating as a lecturer for the master's degree in Steel and Composite Structures and CYPE's master's degree in Structures at Zigurat and giving lectures on specialisation courses in building analysis. In October, in collaboration with the association of industrial engineers EIC Demarcació de Lleida and together with Miquel Ignasi Latorre, another industrial engineer, he gave a course on CYPE Connect, the application developed by CYPE for the analysis of complex connections in steel structures using the finite element method. We talked to Rajadell about being a structural engineer, the challenges of the construction industry and the current training in the speciality of st
How has the structural engineering profession evolved in recent years?
Nowadays, much more use is made of software for analysis to the detriment of the traditional way of analysis. This could be problematic because many professionals often lose or fail to acquire the concepts of how a structure works. Specialists enter data into computers and simply trust the program's results without carrying out a manual study of what the structure should be like in order to foresee how it is going to behave. This results in projects where you find conceptually ill-conceived structures. Whether the results are correct is another matter.
Technology has made work much easier, but specialists' knowledge is still a priority...
"Industrialised construction requires a very important knowledge of construction details and node solving"
Indeed it is. Technology is a great help to those who understand it and a danger to those who don't. That is why there must be knowledge behind the professional. The downside of technology is that it has widened the spectrum of technicians who feel they are able to analyse structures because the program makes it easy for them to do so. Some do not have the ability to interpret whether the results of the program are correct or not. Before, anyone who analysed structures had in-depth knowledge. Nowadays anyone is bold enough to make a building. From my point of view, you have to understand the basics in order to interpret the results and know how the software works, which will help to understand how far the application is capable of going, as the software does not have solutions for every case.
From your point of view, is a structural analyst the same as a structural designer?
To me, it's not the same thing. A designer is like an experienced architectural drafter who models the structure and must know how to do it but has no in-depth knowledge of how the structure works. On the other hand, the analyst is the one who checks that it is resistant. If the two can be combined in the same person, that's perfect, but at some point, this combination of functions is not cost-effective for certain projects.
How do aesthetics and functionality interrelate in structural design?
This is a constant struggle. In both structures and connections, for example, there are times when the design is prioritised in terms of aesthetics. Aesthetics have to be matched with function.
What have you learned from this struggle?
That both can be achieved. We must also bear in mind that functionality is both aesthetic and beautiful. The aim is to find the safest, standard-compliant and cheapest solution that is as aesthetically pleasing as possible. A balance of everything.
Throughout your professional career, you have worked and collaborated with different professional profiles. When you carry out the structural analysis of a building for which you have already received the architectural design, what kind of situations have you encountered?
It depends on the profile of the specialist who carried out the architectural design. The difference between the design of an architect with structural foundations and that of another professional without them is very important. When it is carried out by a technician with structural knowledge, the analysis of the structure is extremely simple and coherent. The project's author had already placed the columns, thinking not only about the interior layout and the layout of the floors, but also placing the columns in the correct position and trying to make the structure fit together. In other cases, I have faced projects where the columns weren’t correctly positioned and didn’t make sense.
How do you act in such situations?
As professionals, we "rescue" it as best we can, or we have the work altered in the most conflictive cases. However, it is important to bear in mind that there are situations in which the plots of land, due to their space, are what condition the design. And that is when the analyst, depending on their knowledge, can enter the structure and interpret the results of the program in the right way, knowing if they are doing it right or if they need to find a safer structural design.
Regarding the use of sustainable materials, are they finding their way into structures?
“Technology is a great help to those who understand it and a danger to those who don't”
Steel is already entirely recycled. If you look at its life cycle, most of it will come recycled already. Concrete is starting to be recycled. In any case, I (the structural analyst) don't normally choose the material. We are presented with a structure and told how it should look. In industrial environments, concrete, steel or composite structures are used.
Regarding the use of other materials such as timber, I think its use will depend on each case. Spain mainly has quarries, so I think that timber would only be used in specific projects, as the country doesn’t have the forests to provide this material at a reasonable cost. And bringing it in from abroad could be more expensive than using concrete from the quarries we have. Therefore, I believe that timber could be used in specific projects, in single-family dwellings, but not as a general solution. We can't use timber like the Swedes, just as they won't be able to use concrete as we do in Spain because they don't have quarries.
Do you think that the use of structural steel will become widespread in Spain?
In Spain, reinforced concrete buildings are made because they are cheaper than steel or timber buildings. For industrial buildings, both metal and concrete structures are used, and there is also a lot of precast concrete. When the price of precast concrete became competitive with steel, it started to be used in the manufacturing sector.
But there is also another factor when it comes to using one material or another in the case of industrial buildings. The aim of these constructions is for an activity to be carried out, and the sooner it is operational, the sooner it will start producing products and earning money. When it comes to manufacturing, the material and structural type are often conditioned by the execution period. For residential use, it isn’t much of a problem if it’s delivered four months behind schedule because during construction the real estate developers spend their time selling the houses.
In recent years there has been a lot of talk about industrialised construction. You have participated in several projects based on this type of construction. What are your conclusions?
I have carried out real estate developments with Light Steel Framing (LSF), hollow sections and also container-type buildings. The fear I have about industrialised construction is that there are a lot of risk-takers and people with no knowledge. Therefore, I would advise real estate developers and professionals to be very careful and to be aware of who they are hiring. Industrialised construction is not the same as installing plasterboard. It requires a very important knowledge of construction details, of solving nodes and of knowing how many bolts to put in. This is very important. Cases can’t be solved with a couple of "little bolts".
Does it have advantages over the traditional construction system?
It's a system that could be quicker, but I don't know if it will become a permanent solution. There is prefabricated construction in concrete, LSF, timber, etc. Within industrialised construction there are different materials and typologies, so I see this way of working as a solution for certain cases. I don't think it will become a general solution for everything because it has its limits.
The importance of training in structural design
As well as your work as a structural analyst, you are also a teacher and trainer. What do you see as the university's strengths and weaknesses in the training of structural design and analysis?
"The physical concepts of classical mechanics must be engraved in the minds of students and professionals who want to analyse structures"
In Spain, knowledge has become very dispersed. I have the feeling that they have tried to cover too much and there are too many subjects. Thinking about the speciality of structures, I would emphasise Physics in the first year. I think that the physical concepts of classical mechanics should be engraved in the students' minds. I have come across 4th-year students or master's students who lacked a solid base in physics, which prevented them from understanding what we were doing in class.
I also think it is important that physics is taught by people who have a similar degree to the one the students are studying. I was taught physics by an industrial mechanical engineer and he knew what I would need from it later in my job. The professor was already preparing us for our future careers, whereas if the subject is taught by a physicist, the chances are that he or she will not know how to analyse structures and will focus on points that aren't as relevant to structural analysis.
In comparison with other countries, do Spanish professionals cover more specialities than what is recommended?
We have to bear in mind that in Spain, the type of technician we traditionally needed was not as specialised as those in Germany, France or England. Here, if an industry had an engineer, they had to be able to do everything: analyse an electrical installation or a beam. What is even worse is what happens with agricultural engineers, who have to know when to irrigate crops as well as when to build the cooperative's warehouse. There are agricultural engineers who are qualified to do both. How do you train such a person? Knowledge has already reached a point where a professional cannot be a universal human and know about everything: they need to be specialised.
Do universities offer this specialisation in an adequate way?
I think that the current curriculum starts the specialisation too late. I started my specialisation between the 4th and 6th year, with three specialisation courses in a six-year degree course. Nowadays, a Bachelor's degree has four years plus a Master's degree, which can be one or two years, which doesn't seem like enough time to me.
CYPE Connect course on bolted connections
Regarding training, in October you offered a course on finite element bolted connections with CYPE Connect. What was the aim of this course?
We want the students who finish the course to master and be able to use the tool. The course is aimed at people who already analyse structures or who have received training in the strength of materials structures, theory of structures and metal structures. They have previous knowledge. During the classes we are going to show them how to use the program as well as our experience in the analysis of connections so that they know why it is carried out this way and not another way, seeing the results of doing it in one way or in another way. The aim is for them to understand how the connections or the modification of one of them influences the behaviour of the structure.
What are the advantages of using CYPE Connect compared to other solutions on the market?
An advantage over any other tool on the market is the connection with analysis and force programs such as CYPE 3D. Thanks to this connection, the specialist making a modification can see how the communication between the two programs is automatically updated. The loads can be modified and the new forces can be imported automatically and reanalysed. This cannot be done with other software. You have to use programs from different manufacturers and the companies involved in the project communicate with a file from each connection, which means that in the end, you are working with 50 different files. And if one is modified, none of them is any good to you. What is trivial in CYPE requires quite a lot of work with spreadsheets in others.
Another advantage of CYPE is the drawing module. Professionals can generate an updated model with drawings of the connection, which can be included in their project and allow for more details. Plus, it has another advantage: the connection can be imported in 3D format and any user can see the connection, avoiding any potential misunderstandings on the construction site.
"The problems that arise in the design phase because we didn't pay attention to the details have to be solved later on the construction site, which can cause serious problems"
In your professional experience, what are the most frequent problems when designing and analysing structural connections?
A common problem is that specialists work in too much of a hurry and don't pay attention to detail. We must bear in mind that the details overlooked during the design phase will have to be fixed later on the construction site. This is extremely problematic. If the specialist is there and the means are there, the right instructions can be given and the problem can be solved. But our job is not to be on site all day long. We visit frequently, but we are not always there. What's more, the solution must be quick because the work can't be stopped. During the execution phase, anything can happen if the work is not well planned, leading to counterproductive measures that could ruin all the previous analyses. This is why it is important to pay attention to detail during the design phase in order to minimise problems as much as possible during the construction work.
This is precisely what industrialised construction tries to avoid. This, as I mentioned earlier, is where it has a competitive advantage because if everything is done well in the previous phase, little or no intervention is needed on-site, leaving less room for mistakes.
CYPE can also export the file in DSTV and STEP format so that workshops can easily fabricate the connections. What do you think of this option?
It is a good feature, but workshops still need to step up a gear from a technological point of view. The workshop industry needs to become more capable in the use of software because most of them lack the technology to read this digitised information, as they are still working with simple software and are not taking advantage of these innovations.
Based on your experience, does the design and structural analysis of structural connections (whether steel or composite) seem more complicated today than it did decades ago? Why is this?
The work is more complicated because we have more knowledge and because we want to have more things under control. Our work is more complicated now than it was 20 years ago, just as 20 years ago it was more difficult than it was 70 years ago. We are becoming increasingly aware that there are things that influence the project, we want to analyse and obtain more information about the connection (strength, stiffness, etc.) and things that we never thought about before, are now things we want to have under control. Due to the enormous amount of information we work with, the engineer is no longer able to do everything. We cannot know everything.
BIM's impact on construction
As an independent professional, you are used to being part of multidisciplinary and international teams. How has the BIM working methodology affected you?
We are starting to receive files in IFC format for different projects. These are very important and unique construction projects. Up until now, we had not received information in these formats, probably because we hadn't been considered an integrated supplier in this workflow. As for my work on projects for industrial warehouses or buildings, I have not yet received any projects to be integrated into this workflow.
Are there any problems in the BIM workflow?
With the IFC format, as far as I can see, we do have a problem. We use industrial software on construction sites and construction software. But there are compatibility problems between them, as the industry is ahead of us. Another handicap is that many of the current IFCs are generated by Revit and are not very good, which makes it difficult for other programs to read their information.
Any others?
Yes, there is a pressing issue with temporary or rental licenses. As a professional, I don't want to work with proprietary software. I don't want a brand's format to be the standard and have to "go through" it when I work via the purchase of a rental license that minimises my professional options. These rental offers mean that if a specialist doesn't have projects that provide them with income, they can't rent the license and therefore don't have the option of running the program and opening their past projects to review them or anything else.
This rental option may be an interesting option for large companies, but for an SME or for freelancers it is not. I want to buy my "perpetual" license which, with a certain version, I will always be able to use in the future and open the job I designed some time ago with the respective version.
