Preface

According to the Longman Dictionary of English Language and Culture, a concept is defined, as a principle or idea. A principle is defined as a truth or belief that is accepted as a base for reasoning or action . Structural concepts are amongst the main foundations for study, analysis and design in civil and structural engineering.

Structural concepts are key elements for students to understand, for lecturers to teach and for engineers to use in civil and structural engineering practice. The teaching of structural concepts at university needs to be enhanced to meet changes and challenges in our current learning environment and in the world of work.

In the past a major part of this understanding has been developed through working with hand calculations and through experience with construction. However, now many hand calculations are replaced by the use of computers and new methods of gaining an understanding of structural concepts are desirable. Indeed the understanding of structural concepts, fundamental to the sound and innovative design of structures (buildings, bridges etc) is even more important because of the wide use of computers and the, often unquestioning, reliance placed on the results of computer analyses which although mathematically correct may be flawed if they are based on incorrect assumptions and modelling. This is one reason for criticisms from the construction industry that graduates tend to place over reliance on the use of computers. Graduates, in general, are good at using computers but many are unable to judge whether the results obtained from computers are correct. This suggests that students may not have become adequately familiar with basic structural concepts during their university studies.

Structural concepts and principles are abstract, and they cannot be seen and felt directly. For instance, force paths transmit loads from their points of action to structural supports, and resonance describes the vibration characteristics of a structure responding to a dynamic load applied at a natural frequency of the structure. If such concepts and principles could be made more observable and touchable, students would be better able to understand and remember them.

Engineering examples are often not provided in textbooks to illustrate the applications of structural concepts. If lecturers could use related engineering examples and convert appropriate research work into teaching, the interest of students would be stimulated and their understanding of structural concepts would inevitably improve.

It has been observed in class situations that students show a greater interest in topics which are demonstrated physically than in topics that are explained by words and blackboard/OHP/PowerPoint presentations. They show an even greater interest in practical examples which illustrate the use of concepts in the solution of engineering problems rather than in coursework examples. Students are motivated by "hands on" experience and by linking concepts and models to real engineering problems.

In such a background, we have been developing what we called seeing and touching structural concepts to supplement traditional class teaching and learning. To enable this, three parallel themes are followed:

• providing a series of simple demonstration models for illustrating structural concepts and principles in conventional class teaching which allow students to gain a better understanding of the concepts;
• providing associated engineering examples to demonstrate the application of the structural concepts and principles which help to bridge the gap between the students knowledge and practice;
• converting appropriate research output, which particularly involves structural concepts, into teaching material to improve existing course contents.

Structural concepts that can be physically demonstrated are identified and simple demonstration models, suitable for class use, are provided to illustrate the concepts. Whenever possible, students have been encouraged to help to design and make these models.

Real interest can be generated and a better understanding can be achieved by seeing how concepts are used in the design of real structures. Therefore engineering examples which can illustrate the application of the concepts in practice have been sought and identified. Poor designs which may be illustrated by collapses have also been studied as such applications can often show the consequences of misunderstanding structural concepts.

R esearch and teaching are undertaken in parallel in universities but links between research output and undergraduate teaching may not always be developed. Research output, which particularly concerns or illustrates structural concepts, has been converted to forms suitable for linking with simple demonstration models and practical applications for use in class teaching. For example, concepts for designing stiffer structures, human whole-body models in structural vibration and the horizontal movements of frame structures induced by vertical loads are presented in the book.

We have developed a number of physical models for illustrating structural concepts and identified a number of engineering cases and every day examples for illustrating the applications of these concepts. These models and examples are normally not included in textbooks but are useful to supplement learning and teaching. Students quickly grasp and remember a concept when it is physically demonstrated and its application is illustrated.

This book, which provides examples of links between structural concepts, simple demonstration models and engineering examples, will be an aid to lecturers and should benefit students and engineers/designers in structural engineering and architecture. It is hoped that it will stimulate the interest of readers to seek further examples of concepts and their applications.

This book is written like a ‘recipe' book; most of the structural concepts in the book are independent and each chapter illustrates one or more related concepts. Each chapter contains four sections:

1. Definitions and Concepts: Definitions of the terms used in the chapter are provided. The concepts are presented concisely in one or two sentences and in a memorable manner. Key points are also given in some chapters.
2. Theoretical Background: If the theory is readily available in textbooks, only a brief summary is presented together with appropriate references. More details are given when the theory is not readily available elsewhere. Selected examples are provided, which aim to show the use of the theory and link with the demonstration models illustrated in the next section.
3. Model Demonstration: Demonstration models are provided with photographs. Normally, two related models are provided to show the differences between the behaviour of the two models thus illustrating the concept. Small-scale experiments are also included in some chapters.
4. Practical Examples: Appropriate engineering examples are given to show how the concept has been applied in practice. Some examples come from everyday life which should be familiar to most people.

Accompanying this book, we have created a website of the same title which can be found at www.structuralconcepts.org. The website contains most of the contents presented in the first, third and fourth sections of each chapter in this book. Colour photos can be downloaded from the website and video clips can be played.

The website and the book have been written initially for students, lecturers and graduate engineers in Civil and Structural Engineering. However the contents may also be useful to similar groups in Architecture, Mechanical and Aerospace Engineering.

To Students

This book provides useful and interesting information to enhance the understanding of structural concepts and to supplement class studies. The level of contents spans from first year to fourth year of a typical undergraduate course.

The contents of the book can be used in different ways:

1. You can look at any particular chapter after you have been introduced to a concept in the classroom to help you to gain a better understanding.
2. You can use the book to revise what you have learnt in the past.
3. You may ask yourself if you can think of another model which is able to illustrate a concept listed (or indeed one that is not listed) or another example which shows the application of a concept.

Some of the models in the book were developed by our students as they knew which concepts were difficult to understand and which concepts could be physically demonstrated.

To Lecturers

We hope the book provides useful material to supplement the teaching of structural concepts. The photos and/or contents in the associated website can be downloaded for teaching.

It is hoped that students learn effectively and actively and this, in part, requires the provision of appropriate activities and/or stimulators. This book and the website can be used for such a purpose. We have asked our third-year undergraduate students to read all the contents of the website relating to Statics and assigned them individual coursework entitled ‘ enhancing the understanding of structural concepts ' for which they needed either to design a physical model to show one structural concept or to identify a practical example where one structural concept was creatively used. This coursework has been received enthusiastically and the returns have been excellent and collected to form a booklet. This was then distributed to all students in the class to form a student source of learning, enabling them to learn from each other rather than from lecturers and textbooks. Some examples provided by the students have been included in this book and added to the website.

To Engineers

The contents of this book and the associated website are useful to engineers, in particular, recent graduate engineers. Unlike university students, you will have gained practical experience but may have forgotten some structural concepts you learned at university. You may find the book and website useful in three ways:

1. You can revise quickly many structural concepts.
2. You can examine the use of each of the concepts in practice through the examples provided. It is hoped that this may generate your own ideas for applying the concepts or indeed any other structural concepts in your work.
3. You can identify, using your own experience, how any of the structural concepts have been used in your work or in the work of your colleagues. Then consider how the application of the concepts helps in enhancing your understanding of structural behaviour and providing more efficient structures.

Engineers aim to achieve safe, economical and elegant designs. A good understanding of structural concepts will help to reach this goal.

Finally, we would very much like to hear from you if you have an idea to illustrate a structural concept using a physical model or have any practical examples in which one or more structural concepts plays an important role. We will acknowledge and add any suitable examples into the website and your contribution will be shared with others, including students, lecturers and practicing engineers.

Tianjian Ji, Adrian Bell
School of Mechanical, Aerospace and Civil Engineering
The University of Manchester