Introduction
Design patterns are a relatively new concept in software engineering, and have their origins in civil engineering. Essentially they are a blueprint for solving a specific problem, allowing the benefits of an optimal solution to be carried forward to new implementations.

The application of design patterns to the domain of software engineering was first formalised in the book “Design Patterns: Elements of Reusable Object-Oriented Software” by Eric Gamma, Richard Helm, Ralph Johnson, and John Vlissides, in 1995. The book selected 23 patterns considered to be core to understanding the pattern approach in solving software engineering problems.

While this book also set out many principles, it did not make a general template for pattern use available to the wider audience. Subsequently, applying patterns has not yet itself become a pattern-driven exercise. Engineers are left to decide how best to use patterns in different applications.

Structure of Design Patterns
What is clear is that there needs to be structure into which patterns can be formulated; this allows for them to be largely self-documenting. Indeed, one of the principles of using design patterns is that they should be structured, allowing each one to be created from a template.

At the very least, a template should contain:

• Pattern name : short, but descriptive;

• Intent : the goal of the pattern;

• Motivation : example of a problem, and how this pattern will solve it;

• Applicability : uses for this pattern;

• Structure : diagrams of the patterns classes;

• Participants : the responsibilities of the classes in the pattern;

• Collaborations : interfaces between the participants;

• Consequences : any trade-offs and forces that exist within the pattern.

This list is adapted from that provided by the Design Patterns authors, and can be used as rigidly or as loosely as is required. Some aspects will prove not to add any useful value to the template, but are provided here in the interest of completeness.

We have also refrained from using the term ‘classes and objects’, as is common in discussions of design patterns, preferring to only use the term ‘classes’. The reason for this is one of object oriented design preference – if a pattern needs to be defined in terms of objects, then a certain implementation decision has been made and forced upon future adopters of the specific pattern.

Application of Design Patterns in Software Engineering
One of the key benefits in using design patterns in software engineering is as a way to improve communication between designers, and, to a certain extent, between non-programmers and programmers. In other words, as a communication tool, patterns can prove invaluable.

In addition, by abstracting solutions to common software engineering problems, design patterns can be used again and again. Since they use a proven solution each time, reuse at the design level is very high. This improves the quality of resulting implementations beyond that which would be achievable using only object oriented techniques.

The application of design patterns in the real world must necessarily be carried out with reference to other principles already deployed. In other words, while they offer solutions to common software engineering problems, there is no added value in creating patterns for every part of a system under development.

Instead, they should be used in cases where the resulting implementation (or design) is likely to have a use in future projects. In essence, the best way to use design patterns in software engineering is in providing standard behaviours between highly specialised classes in a software system. The are not a design technique per se, in the way that other paradigms are.

Summary
The reasons for using design patterns are essentially parallel to those for using any object oriented techniques. Design patterns encourage reuse, without constraining implementations to a specific platform or language, and promote efficient use of design time. They can be seen as the design equivalent of modular or object oriented programming.

Their strengths, however, can also be seen as their weakness. By not being implementations, the programmer is still required to actually code them, and as such any errors in the interpretation will be translated into the final source code. This means that different programmers may end up with different implementations of the same pattern, possibly even with different behaviours.

When working with design patterns, it is therefore important to remember that they should be precise enough that there are no possible misinterpretations. Using a suitable high level definition language that can be shown to be correct will help to ensure this.

GOOD PROCEDURE IN THE DESIGN PROCESS

Designing

1. Produce a good preliminary key, with preliminary beam sizing and fairly firm structural system and beam naming. Beam naming should be treated like Identity Card number, cannot be changed but can be omitted.
2. Produce an A3 size for design documentation together with A3 architectural drawings.
3. Produce a hardcopy, which is big enough to mark loading.
4. Do the minor beam (tertiary or secondary beam) first. Once completed, marked point load into the drawings. In this way, no important point load will be missed. Further, when more point load is being put in, try to compare with other to sense for gloss error. If suspect, go back to the calculation. In the way, the structural sense wills slowly being developed.
5. Coloured the completed beam with light colour to mark the small achievement and step forward.
6. Learn to enjoy the design process.

Detailing

1. Produce a hardcopy, which is big enough to mark loading.
2. For each beam done, mark the steel bar for support and mid span, converted into equivalent number of Y25 bar (or any bar size).
3. Colour the completed beam with light colour to mark the small achievement and step forward.
4. Compare with other completed beam periodically or when doubt arise, try to sense gloss error. If suspect, go back to the calculation. In the way, the structural sense will slowly being further developed.

A strong sense of possible error can be developed when doing the above for typical floor of fairly uniform column grid and loading pattern. A repeated advice, while building your structural sense, please notes that company does not get immediately extra payment from the clients. Be fairly to the company.

Good Practice

Column is usually not designed for uplift. Most people at site is also not use to uplift. It is good practice to minimum uplift by:-

1. Split the beam into simply supported beams to avoid lifted.
2. Minimised uplift by putting additional span bar and opposite support link as a conservative measure.
3. When the support and span of a span is big, take care of the midspan top bar as hogging may occur.
4. For beam design based on single case of loading, need to take care of the end span link of a continuous beam and the top bar of the first interior support.
5. There are many design calculation variations, a perfect calculation is not really possible and there are numerous changes in the design and construction process. Every engineers need to learn the art of changes, Architectural requirements, Mechanical & Electrical requirement as times go along.

Tags : engineer, engineers, engineering, drawings, design, knowledge, beams, procedure, process, detailing, structural, system, architectural, building, sense

COMMON MISTAKES OF NEW ENGINEER (General for Beam, Slab and Column)

Staircase

The loading from the staircase landing stiffer/column is always missed out. Need to study the architectural drawings properly. The mid-landing always have mid landing beam supported by column stiffeners, which sit on beam at floor below. If the floor height is high, then there may be more than one landing.

For the first flight of the staircase, below the staircase, there is slab. If the floor is suspended, the loading to the beam need to be taken into account.

To take care of multiple flight loading if the floor height is high in relation to the length of the staircase.

Brickwall

The brickwall loading, many engineers try to be accurate and take the exact brickwalll height from beam soffit to floor. The typical floor design, the load of brickwall should be taken from floor to floor unless the roof beam profile is the same as typical floor. Otherwise, the highest typical floor may not be the same as the lower floor.

Water Tank Above Toilet

Even if this is indicated in Architectural Drawing, more often than not are without the size. This water tank is normally supported by individual timber or steel channel supported by Brickwall.

Edge Beam

• For area which need ceiling but without edge wall, the edge/perimeter beam may need to be deeper to accomodate.
• For beam above aluminium sliding door, the beam may need to be deepen to avoid the use of lintel which rum through form column to column.
• For roller shutter, the use of perpendicular beam of full depth may not be allowed.

Slab

The slab is often being designed for individual panel only. Due to this, if two adjacent panel is of different thickness, the heavy moment is designed using the thicker slab which is not correct.

If the detailing is done to 0.3 span, the distribution bar from main bar (on long span) becomes the main secondary bar. The main rebar for secondary panel may need to be increased proportional due to the reduction.

Calculation

The design calculation is a final document, not exercise or test or exam where you are allowed to make a 25% error and get an A for excellence. The calculation must be correct. If there is any thing unsure, you are supposed to ask. If you get deflection problem or maximum shear exceeds the required warning, solve the problem or ask senior for solution. Do not leave the wrong calculation to be check by Senior or the alertness  of Senior. One beam collapse out of few hundred cans sent someone and the engineer to hell.

If things is shown not okay in computer print out due to certain conservative assumption but you know this is not critical, write down the word “OK” and if possible put down the reason.

Window Bay

In first floor design for a double storey house, for window bay for room, the slab need to be designed as a cantilever slab with additional beam around the bay window. For roof area, additional facial and slab cover need to be provided. Unless the fascia beam is supported by stiffener/column to the floor slab, the roof beam need to check for torsion stress.

Required Accuracy

It is impossible to achieve a perfect calculation as there are amendment requirement to architectural function and details, M/E details, structural detailing and standardisation, etc. Theoretically brickwall on beam is affected by column width, the depth of beam on top, any airconditional hanging on it, window, etc. The concrete in the beam and slab intersection, beam intersection, etc. may be accounted twice.

It is practical for loading that is not critical, just be a bit conservative and live with it. Eg., when beam sizes varies, it is ok to take the larger one. To details make design life miserable and divert attention from more critical issue.

Overall a loading accuracy of 5 % higher should be consider good standard.

Tags : engineer, engineering, design, beam, beams, slab, column, drawings, mistakes, knowledge

Engineering careers have been the top choice for people to study in the universities. Have you been considering to work in the engineering industry but you would like to understand more about it first? A lot of people consider this as a occupation, but they are not really sure where to begin and hence, they could make the bad decisions. You may or may not be aware of this, but it is such a wide field to explore into, so read through this article to learn more about this industry.

What is the best engineering field should you go for and will it meet your expectations?

It is true that this line of work can produce you with a handsome salary each every single year. Nevertheless, pursuing for the right engineering job that you really wanted is not easy at all, unless you are absolute of what you want to be, you could be left wondering around with the huge number of choices. Choices like civil, mechanical, electrical, software, computer, aeronautical and the list goes on.

Since there are too many options, you really need to go deep into your heart and find the one that suit you the most. This is one career that you do not want to mess with. Listen to this story for example. John is a civil engineer who is given a task to design one bungalow. If John does not design the bungalow properly since he is still wondering why he become a civil engineer while his interest is more on mechanical things, surely that poor bungalow might collapse or crack all over the place.

If you have a knowledge for computers, then computer engineering could be what you are dying to learn more. Also, you need to have a list of expectations and then see whether the task you like really matches the one you fill comfortable with. If you are somehow lost and need somebody to assist you, try to seek advice from a career advisor or do plenty of research to help guide you.

Will engineering provide you with a lot of money in the future?

Definitely yes. There are many successful engineers in this world who have a luxurious life after working for just several years. But you have to understand this, if you would like to be one, you should know that you have a very challenging career ahead of you. It is a very tough career and therefore, the person applying for this job should know exactly what they are letting themselves in for.

If you think about it, engineering careers will definitely increase your level of thinking and communication skill simultaneously. You are just not only going to be respect by other people, but you will fill a lot of satisfaction once you are really master at what you do. 

Tags : engineer, engineering, professional, professionals, profession, construction, project, site, management, civil, electrical, mechanical, computer

BEAM DETAILING

Number of bar in one layer

Beam width divided by 75mm, 125 of 150, 175, 200 use 2, 225 use 2, 300 use 4, etc. Normal beam use is 125mm (internal)/150mm(external), 230mm, 300mm, 450mm, 600mm, 750mm, 900mm, 1200mm, 1500mm, etc. Do not use 200mm under normal circumstances, as it is too wide for 2 bar and too thin for 3 bar.

Number of layer (top or bottom) maximum 1 for 300mm beam depth, 2 for 450mm depth, 3 for 600mm depth to 750mm depth. Beam width to adjust to reduce number of layers.

For beam with cover of 40mm (exposed to weather or underground), 150mm width can only accommodate to 2 No. of 16mm. For upper floor external beam, with one size 20mm and their other size 40mm, Y25 can be used. In some case we may need to use 175 or 200mm.

Try to make optimize bar length of 12m (12m, 6m, 4m, 3m, 2,4m, 2m, 1.5m, etc.). If possible use whole number and not 5.75m but use 5.8m if not 6 m.

Use symmetrical arrangement.

Support Bar

• Allow for 5-10% more.
• Minimum 50% (try to use 60%) to go to 0.3 span and the rest 0.15 span.
• Mark as _Y25 (4m) + _Y20 format.
• Mid span top bar.
• Normally use nominal bar to tie link unless there is compression bars or tension due to heavy support moment.
• Normally the first interior span mid span top bar will be slight more.

Span Bar

Follow the curtainment rule as follow:-

• Simply support end : minimum 50% go thought, the rest 50% reach 0.08 from support.
• Interior span : minimum 40% go thought, the rest go to 0.15 from support.

For end span allow 15% more.

For first interior span add 40% more.

For interior span add 30% more.

Try to allow some bar go throughout the span. Normally this is possible except the end span in which case use different bar size. Use marking a _Y25 thought + _Y20 (5m).

Shear

Allowance for at 10% more. In term of Asv/Sv.

Rebar choice.

To curtain steel bar, we should choose steel bar sizes properly. Preference should be given for single layer and bigger bar size with the same equivalent area. Eg. 3Y20 of 4m (first layer) + 2Y12 of 2m (second layer) is not as good as 2Y20(4m) + 1Y25(2.4m) all in one layer.

• Y10 only should be grouped with Y12, not Y16 and above.
• Y12 should be grouped with Y10 and Y16, not Y20 and above.
• Y16 should be grouped with Y20 and Y25, not Y32 and above.

Tags : engineer, engineering, civil, design, beam, beams, shear, rebar, detail, details, detailing

STAIRCASE

Staircase is a confusing to most fresh engineers. The staircase drawings is done after the design. Always, the point load from the column/stiffener supporting the mid landing is not design for in the beam or column. It is even more complicated when due to higher floor height, more than one landing is required. Fresh engineer is advised to pay special attention to visualise the staircase system, especially when go to the site.

Staircase ultimate loading = 1/2 x length of staircase x 18 kN/m2, to be checked upon completion of design.

Landing beam

The landing beam midway between floors is never shown on the layout. The height of the column supporting the landing beam is about 1.5m, therefore at every 3m floor height there is one landing beam.

Beam B1 and B4 carries half of the staircase weight which is 18 kN/m2 and slab loading. The landing will carry half of the staircase weight in addition to brickwall height.

Tags : engineer, engineering, civil, staircase, design, drawings, beam, beams, structure

REBAR

Reinforcement Used

• Steel Bar (denote as T @ Y)   = 460 N/mm2
• Links (denote as R)               = 250 N/mm2

The rebar diameter used here is 10mm, 12mm, 16mm, 20mm, 25mm, 32mm (seldom), 40mm (seldom). Remember to provide rebar spacing not less than 20mm.

Links

Links should be provided; 6 and 10mm diameter.

BEAM ARRANGEMENT

Primary & Secondary Beam

A primary beam is supported by two columns. Beam should transfer load directly (as direct as possible) to columns or primary beam. If possible try to make the beams equally spanned.

Which beam supports which beam

• Let the loading goes directly to columns.
• The shorter beam supports the longer beam.
• The wider beam supports the thinner beam.
• Try to make all the beams equal span.
• Try to make the loading almost equal throughout the span.

Negative support force

It is normal to have negative support force. The negative force at support will cause an uplift on the other beam. Therefore the beam should be designed for the uplift; top reinforcement. Also run another case when the uplift force is zero, so that the bottom reinforcement is designed more conservatively.

If the beam is jointed to the column, and the total of all the forces of the column is negative than some solution must thought, since columns are not to carry tension load, just compression loading.

Beam naming

If grid exist, beams to be named with grids, instead of the other name to make key plan neater, checking easier. Naming and presentation, always from left to right and bottom to top.

Head room

Care to be taken to ensure that there is enough head room, normally 2.1m above staircase, care ramp, etc.

Gradient of ramp

Beam alignment may need to be moved to ensure that ramp have sufficient gradient of 1 (vertical) : 7 (horizontal) for straight ramp (circular ramp is 1:10). This happen when grid line is at 8.1m centre and the floor height is 2.75 with split floor. 1.375 at gradient of 1:7 need a horizontal beam distance of 1.375 x 7 = 9.625m. The beams at gridlines need to be set back (9.625 - 8.1)/s + half beam width = 0.7625 + beam width.

BEAM COVER

The cover of the beam is 20mm if exposed internally and 40mm if exposed externally.

 

 

 

 

Tags : engineer, engineering, civil, beam, beams, ramp, steel, reinforcement, rebar

Electricity is ubiquitous from your personal cellular to large transportation systems such as the subway or planes. Since its invention, electricity has made our life much easier and convenient. But electricity would be only an energy source without people creating and maintaining equipments or applications using it. Electrical engineers are the people who create, improve and maintain electronic devices and equipments. Because of the ubiquity of electricity, electrical engineers can be found in any industrial branches of the economy and may work on as many different products as cars, robots, cell phone systems, or lighting and wiring systems in buildings. Indeed, whether you take a look at the personal electronic, plane or automotive industry electrical engineers play a core role designing the circuits and electronics parts, testing designs and improving them.

As the field of work for electrical engineers is wide, there is a common distinction made between an electrical engineer and an electronic engineer. Electrical engineers typically deal with large-scale electrical systems such as power transmission and motor control, whereas electronic engineers typically deal with the study of small-scale electronic systems such as computers and integrated circuits

How to become an electrical engineer? If you want to embrace a career as an electrical engineer, you are generally required to graduate from college in engineering. Just like any other engineering career, you will need to have excellent grade in mathematics and science to study in an engineering schools. Being a science-oriented student is not enough, you will be required to have good skills in English, social studies, and computers. Most recruiters also expect their engineers to be creative, curious, logical, detail-oriented and good team-workers.

In the U.S., there were about 299,000 electrical engineers and electronics engineers in 2004. Most of them worked for companies manufacturing medical device, communications equipment, or electronics. Despite varying greatly from one sector to another, electrical engineers earn in average $67,340. Besides prospects for electrical engineers are very good since jobs are expected to grow about as fast as the average for all occupations through 2014.

Electric Job can help you find electrical jobs, engineering jobs, and utility jobs and all jobs in the electrical jobs and engineering jobs industry. Electrical jobs, engineering jobs, electrician jobs, lineman jobs, power jobs, energy jobs, utility jobs, careers, and employment search.

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So you just got accepted in your engineering program…joy, but you are still doubtful. You ask yourself, could I actually handle the stress, the sleepless nights, the solitary life style and the Exams? Well hopefully after reading this guide you might just be able to do so and perhaps without going insane or bald.

Buy a Calendar.

Yes I know what you are thinking a calendar but I don’t need a calendar. I was like that too, heck I never used my agenda through out high school, and I managed to reach here right? Wrong! This is not high school and if you miss a due date for a test or exam you can not tell your mommy to write a note. Trust me I tried. Time management skill is vital if not necessary, it helps you plan for the endless upcoming due dates of assignments and gives you a better picture of what tests to study for. A common miscomputation is that you can keep up with all your courses every week. This is impossible especially if you want any resemblance of a social life. Firstly forget the time you think you might be able to put aside during the weekday. After a long day of lectures and labs you will be too tired to do anything and its best just to get a good night sleep. So, the only real time you got to study, play and sleep is during the weekend. Hence, a Calendar will help you in deciding what course to study for, what homework or assignment to do, and if it’s really ok to get wasted that night.

Join a Study Group.

I can not emphasize the importance of study groups, especially in engineering. Study groups are not only for dummies, they also help nerds. For the dummies this is the perfect opportunity to understand the problem and to get vital input from others and for the nerds it gives an opportunity to revise and really understand the course material. For, there is no better way of studying then teaching others what you know. Apart from helping you pass the course, study groups also help to socialize us engineers. I mean you could go to library and study all by your self, achieve the top marks in class and graduate with honors but how effective of an engineer would you be in the real world? In the real world you won’t be given a list of problems to be completed in a 2 hour time period, but rather as an engineer you will be expected to work with others and on problems which rarely have fixed or single solutions.

Learn to Skip.

Astonishing as it may sound, but I think it is vital for first year students to learn when to skip their classes. I mean you can’t skip all your classes but can and in most cases must in order to pass the course. Again the problem arises from the fact that as a first year engineer you have a finite amount of time to study and in most cases the weekend period is not enough. So for the greater good you will have to skip the liberal studies lecture or the optional tutorial. I would rather see a student skip a class to study for a test then for him/her to show up for class and worry about the upcoming test or quiz later that day.

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If you’re looking for a career that’s financially rewarding, challenging, and interesting, you’ll want to take a look at the best engineering colleges and what they have to offer. The field of engineering continues to expand so that it now includes everything from aerospace engineering to computer software engineering and technology management. Engineers are teaching, consulting, inventing, running their own businesses and landing CEO jobs. Forecasts for the future say it’s only going to get better.

For those who attend the best engineering schools, the employment outlook is encouraging. While a few areas, such as mining and petroleum are showing declining employment rates, other areas are holding steady or growing. For graduates of the best engineering colleges, the job market for biomedical engineering, computer hardware and software engineering, and environmental engineering is expected to grow by 30 - 40% by 2014.

Choosing from the best colleges for engineering will give you a competitive edge in the job market as well. It’s worth investing the time and effort to find a good school: there is no substitute for great qualifications when it comes to getting the job that will launch you on a long and rewarding career. The best engineering colleges will not only offer you a range of possible career specialties, but they will also offer helpful academic advice and high quality instruction.

The Bureau of Labor Statistics tells us that the earning potential for engineers is high. Graduates of the best engineering colleges earn in the range of $48,000US to $79,000US. The highest earners are nuclear engineers, petroleum engineers, aerospace engineers, and computer hardware and software engineers. Civil engineers, environmental engineers, mining engineers and biomedical engineers are all in the mid range, but have strong future prospects. Check into the salary range for your particular area of interest and then seek out the best engineering schools for that niche, if that remains your choice.

It’s no accident that engineers report high job satisfaction: education obtained at the best engineering colleges prepares them for work that is both interesting and beneficial to society. And while they are working engineers are able to maintain a secure, high standard of living. The fast pace of technological change, the global village, and the challenges posed by climate change mean that employment prospects for graduates of the best colleges for engineering will remain good.

Of course, the earning potential of a graduate from one of the best engineering schools is even higher if he or she ultimately lands a CEO position. This might not be in your plans as you are just starting your carrier, but you might be surprised at where good qualifications combined with years of experience, will get you. Enrollments at one of the best colleges for engineering is a great place to start your journey.

About The Author

R. Drysdale is a contributing editor to Best Engineering Colleges, your one stop resource for the very best online college degree programs.

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