Blog of eng. Xosé Carreira (since 2007)

Structures, water, computers, languages and people (not necessarily in this order)

Freelancing for Structural Engineers: specialization, collaboration and opportunity

In the world of structural engineering, the path to freelancing success is as diverse as the structures we design. Whether you hold a simple 3-year degree or boast a PhD from a top-tier university, the keys to thriving in this field are deeply rooted in specialization, collaboration and tons of patience.

Finding Your Niche: The first rule of freelance structural engineering is to identify a niche. Your specialization determines your bargaining power and fee structure in a competitive landscape. For example, some engineers, like myself, specialize in computer modeling for energy and water-related structures, from tanks to levees. Finding your unique expertise is the cornerstone of your freelance journey.

Qualifications vs. Portfolio: While qualifications are important, many clients are more interested in your portfolio than your academic credentials. Real-world experience and a network of contacts, including architects and fellow engineers, are essential before taking the leap into freelancing. If you're new to the game, platforms like Upwork, Freelance, and Guru can be your launchpad. Build your visibility through LinkedIn, engineering forums, and social media to showcase your capabilities.

Building Relationships: Freelancing is not just about technical prowess; it is about relationships and reputation. Most successful freelancers rely on referrals from friends, family and colleagues. Attending professional meetings and maintaining an online presence can also lead to exciting opportunities. You might stumble upon small-scale projects that are not viable for larger firms but are perfect for your freelance portfolio.

The Collaborative Approach: Beyond traditional freelancing, the construction industry thrives on collaboration. Contractors often seek the expertise of independent professional engineers for calculations and structural assessments, particularly for minor elements like handrails and staircases. This creates a win-win scenario, where engineers can outsource some of their work to freelancers while maintaining quality control.

Expand Your Network: To secure a steady stream of jobs, it is crucial to build relationships with professionals in contractor firms. These connections can lead to collaborative opportunities that benefit both parties involved. As an independent professional engineer or a freelancer, these alliances can help you grow your portfolio and income.

Ambition and Integrity: In the world of freelance structural engineering, ambition is encouraged, but greed is discouraged. Stay humble, and never work for free. Honesty and consistency are the cornerstones of a successful career. Building a reputation for integrity will serve you well in the long run, ensuring not only financial rewards but also respect within the industry.

In a profession driven by innovation, specialization, and collaboration, freelance structural engineers have the opportunity to shape the future of construction while enjoying the satisfaction of a well-earned income. Remember, the path to success is as diverse as the structures we engineer, and with patience, ambition, and integrity, you can build a rewarding career in this dynamic field.

Unfortunate flaws that make the human body a poorly engineered design

The human body is a complex system that has evolved over millions of years to optimize survival and function in its environment. However, from an engineering perspective, there are some aspects of the human body that may not be considered as "good design".

One challenge is that the human body is a generalist system that cannot be upgraded or optimized for a specific purpose. It has evolved through natural selection to adapt to a wide range of environmental conditions and functions. Additionally, the human body lacks project documentation, and many parts cannot be replicated.

Dual function organs are one of the most problematic features of the human body. For example, the same anatomical structure is used for both ingestion and respiration, which can lead to choking and accidental death. The double reproductive and urinary function can also create infection problems. Human females have a narrow birth canal, resulting in increased risks during birth and extreme pain.

Structurally, the human body is relatively weak compared to many engineered structures. It is not optimized for distributing assimetric loads evenly, which can often lead to musculoskeletal problems such as back pain. The spine's S-shape and the complicated design of the foot (with more than twenty moving parts!) are a consequence of our evolution from four-legged apes to two-legged creatures.

Biological limitations such as the limited ability to regenerate or replace damaged parts, and the susceptibility of joints to damage, are inherent in the human body. Energy efficiency is also a weakness compared to many engineering artifacts.

In conclusion, while the human body is a remarkable system, its limitations and overcomplexities that are inherent in its natural evolution may not make it a "good design" from a pure engineering perspective.

Two recent erroneous predictions made by geologists

There are two important and relatively recent geological predictions that mainstream geology had to change its mind:

1. The belief in the expanding Earth theory in the early 20th century, which proposed that the Earth's surface was expanding and that new land was constantly being created. This theory was disproved through more accurate measurements of the Earth's size and shape. Evolutionary biologists always believed that the continents used to be connected but the theory of continental drift, which had been around for decades, was largely dismissed by geologists until the 1960s.



2. The prediction of a major volcanic eruption at Mount St. Helens in the 1980s, which was based on an increase in seismic activity and deformation of the volcano's dome. Most of those geologists worked with  the prestigious United States Geological Survey (USGS). While the volcano did eventually erupt, the eruption was smaller and less destructive than predicted.

 It is important to note that scientific predictions are always subject to revision and improvement as new data becomes available, and these examples are not meant to discredit the work of geologists, but to show that even with the best data and models, geological predictions can be wrong sometimes.

Hardy Cross and the sin of arrogance

Once a student named Alford told [Professor Hardy] Cross that he thought one of the problem solutions in their text was wrong. Cross paced back and forth, staring hard at the student, and pointing at him fiercely. "Can you, a graduate student, actually have the temerity to accuse the internationally known engineer who wrote this book of making a mistake? Can you really believe that the publishers would allow such an alleged error to be printed? Can you show us the error?".

Alford seemed unable to answer.

Still pacing, Cross said, "Can anyone help Mr. Alford? Do any of you see a mistake in problem four?"

The class was silent.

"Well, Mr. Alford," Cross said sternly, "would you care to retract your accusation?"

"It's just that I can't..."

"Speak up!" Cross thundered.

"I still believe it's wrong!" Alford shouted, his face red with embarrassment.

"Then kindly come to the board and prove it to us," Cross taunted. "We shall be pleased to see the proof of your unfounded allegation."

Alford labored at the board without success for the rest of the period.

Cross began his next lecture by saying, "In our last meeting Mr. Alford raised a serious and unfounded charge against the author of our text." Staring at Alford, he said, "Have you reconsidered your accusation?"


"No, sir," Alford replied. "I still believe he is wrong."

"To the board, then. We still await your proof."

Alford's labors were again unsuccessful.

The third time the class met, Cross said, "Mr. Alford, are you ready to withdraw your ill- considered accusation about problem four?"

Moments later Alford was at the board. Within a few minutes he managed to show the solution to the problem in the book was incorrect, and he returned to his seat. Cross's pleasure was evident from his expression. 

"You must always have the courage of your convictions," he said. "Mr. Alford does; apparently the rest of you do not, or you are not yet sufficiently well educated to realize that authority — the authority of a reputation or the authority of a printed page — means very little. All of you should hope to someday develop as much insight and persistence as Mr. Alford."

Reference: Kingery, A., Berg, R. D., & Schillinger, E. H. (1967). Men and ideas in engineering: Twelve histories from Illinois. College of Engineering, University of Illinois.

Picture: Civil engineering lecture at University of Illinois.

Why you cannot really understand science and technology books?

Often in Maths and Physics textbooks the authors omit crucial steps and leave you lost. In addition, understanding technical books usually requires a broad knowledge of the sciences and mathematics involved. If you have no experience, it will be like trying to read a book in a foreign language. 

If you are trying to be a self-learner, you may use a textbook as a guide to the topics to study in what order and to get started on each topic, but when you feel confused, go online and Google any topic you are confused about. You will probably find several sites with different explanations on the same topic. Examine them until you find one that makes sense to you. YouTube can also be very useful here.


I have read my share of science and technology textbooks at post-graduate level and I realized that there are mainly two types of understanding in these areas:

- A conceptual understanding of the topics without getting to the core of the problems. You will probably be able to convince people that you know these topics, because you are able to explain them so that most people understand. Many managers, consultants and even teachers are stuck at this level.

- A deep understanding of the topics, that comes from solving problem after problem and reflecting on them. You will have a complete understanding of the topics gained from working through exercises and will be able to apply what you have learned to solve similar problems. To make sure you are understanding properly, at least at the beginning, it is a good idea to check your ideas with someone who has more experience and knowledge in the subject.

Reading a technical book to gain a deeper understanding is not a fast or easy approach but it is worth in the long run.