Precast Concrete Construction

In the mid-nineties, I was heading a civil design department for a large EPC contractor in South East Asia. We had received an order to build a paper plant.

The primary building in a paper plant is the paper machine building. A typical paper machine building is about 300 m long. The building typically has two floors, one at ground level, and one at about 7.5 m level. The paper machine is installed on a foundation that is not connected to the building. The machine is accessible from the machine hall at 7.50 m level. This building houses other complex and heavy machinery and has very stringent requirements with respect to quality, structural design and stability. The roof is high up and some of the sections of this building are subject to temperatures between 50 to 60 0 C. A large overhead crane straddles the upstairs machine hall. The differential settlement in the paper machine foundation has to be less than one mm and overall settlement at any point less than 1.25 mm. This building, with all its components and the equipment foundations, normally takes 18 months to build.

Our managing director was an innovative man and regularly thought ideas to speed up construction. One day, he called me to his office and showed me an article narrating about a company in the US that had developed techniques to build a paper machine building using pre cast elements. This paper machine building was completed in a record time of 6 months, said the article. We indicated the US company as our consultants and they did the engineering with the help of our engineers in our office. We built our paper machine building in a year cutting down the time by about six months. This was permanently a delay of about three months due to the learning curve and the time required for setting up a precast plant.

Thus began my twenty two years long association with pre-cast concrete. My old company has built several large industrial plants and other structures since then.

In many first world countries pre cast elements for bridges, culverts have been standardized. Pre-casting units are located near major cities that supply these elements to the construction sites. This not only reduces the construction time but also the design time as one uses standard elements whose properties are known.

There are variations of the precast concrete construction such as tilt up construction, module fitments etc.

I have often wonder why India, with so much construction needed in the all sectors of construction, has not embroidered this technique. Apart from other issues like need for repetition, unfriendly taxation, requirement of transport or lifting machinery etc., I think our engineers have not given a serious thought to developing this technique.

I would like to share some of my learnings.

1. Planning is Paramount: The structure to be built from precast elements has to be broken down in elements, in a pre-determined configuration. It is like making the pieces of a Jigsaw puzzle that when put together will form the completed puzzle. It can be a combination of standard and non-standard pieces.

2. God is in details: Each element that planned has to be detailed out to fit all the elements on all its sides and the embedment required for utilities.

3. Design the Construction and Construct the design: Normal structural engineering practice of designing the final product and leaving the "How?" to the construction personnel, does not work in precast. The structural engineer has to stay involved in the process of pre casting, erection and placement.

To the best of my knowledge, IS codes do not have specific provisions for pre cast structures unlike ACI or BS codes. Some of the clauses in ACI can be substituted by provisions in their supplementary publications. Such provisions have to be applied judiciously after a proper assessment of the stages in the service life of the element. A foreseen expert on pre-casting once said "Applying provisions of RCC code to pre-casting would be like playing tennis with a baseball bat"

The structural design for a precast element is done for various stages of its early life. Multiple level checks are required till the element is placed, more checks are required if it is a pre-stressed element with partial un-bonding of tendons.

4. Joints can cause headaches: Resolving and configuring a joint between precast elements can be an arduous task. It becomes a heuristic process to balance between the structural requirement, functionality with respect to basic consideration as water tightness, and the size of the elements to which an element in consideration is attached. Joints have to be constructed the way they have been envisaged.

5. Cutting off ears because they stick out, not only impairs hearing but also creates difficulty in wearing spectacles: This is known to occur frequently where architectural requirements are of primary importance. Typically some architects do not like some essential arrangements created for better joints. Doing away with these "hindering" details may lead to reduced functionality of the joints or the elements. Expensive alternate arrangements are required to restore functionality.

6. Construction Methodology can make or break a project: Many years ago, a large bulk warehouse with pre-cast pre stressed concrete bow string girders as roof trusses was being constructed in India for a fertilizer plant. Out of twelve bowstring girders, six broke while being lifted while the others were issued smoothly. Designs were checked and double checked and checked again. This was before the easy availability of the sophisticated finite element analysis that we have today. It finally dawned on someone that the bow string girders broke because a girder while being lifted in tandem by two cranes, twisted out of plane due to different rates of lifting. A structural engineer designing precast elements should, therefore, have the knowledge of the lifting process.

7. Quality is the watchword: Consistent Quality of production is one of the arguments put forward by the advocates of precast. But many a mismatches, rejections and failures have occurred due to watching only the quality of concrete and giving less importance to placement of reinforcement embeds and the dimensional tolerances.

8. A one rupee increase in the production cost can mean a crore of rupees at the end: Due the repetitive nature of the cost of pre-casting a lot of thought has to be given to use any "nice to have" component. While the most obvious cost elements related to concrete are observed vigilantly, a small embed or a detail, that is incorporated in the design and casting of an element for a probable use, escapes attention. Such an embed that was proposed to be used and has been cast in the element has already added to the cost of producing the element. When a number of such elements are cast, the expenditure can be substantial. If such redundancy if not eliminated in time, it can waste lakhs of rupees.

6 Steps That Guarantee Maximum Price When Selling Domain Names

Whether you are a professional domain name trader or an internet businessperson looking to sell you website, you want to get the best possible price for your domain name. To accomplish that you need to plan and be ready. Use the following steps to ensure the best price when you decide to sell your domain name.

Assess the value of your domain name . There are many factors to consider when determining the value of a domain. If you are not sure how to do this, there are companies that make these assessments for a fee. Probably the most important factors to consider are traffic, length of the name and whether it is a dot-com TLD. Research the market value for domain names in as many categories as possible such as aftermarket domains, sounding domains, secondary market domains, high-value domains, and top domains.

Keep financial reports and tax filings current and correct . Interested buyers usually want to buy immediately and will be put off if your information is confusing or they have to wait for a financial statement. If you have difficulty maintaining your records in a timely and accurate manner, you may want to consider using a CPA or a good software program for this purpose.

Consider the Market . Timing is everything. Pay particular attention to what is happening in your market niche and try to take advantage of peak times for sellers. Postpone selling if your market is experiencing a downturn unless you have no other option.

Avoid ambiguities . Correct anything that might seem unusual or confusing before you try to sell your domain name. Look at your site objectively. Eliminate complications, such as a mixture of revenue from more than one site. The simpler and cleaner your website is, the better chance of obtaining top dollar.

Be real in your expectations . Domains that sell for thousands of dollars are rare. There are tools available to help you accurately assess your domain's value. Use one if necessary and price it accordingly. If you are in a competitive market, you may be required to accept a noncompete agreement.

Use a variety of strategies to advertise your intention to sell . A few possibilities are:

  • List your site with an auction site or other marketplace.
  • Approach buyers directly.
  • Put a "for sale" sign on your domain's home page.
  • Contact your domain name registrar and ask about their sales tools.
  • Make sure your intention to sell is extremely visible. Also, make sure all methods of advertisement contain multiple ways for prospective buyers to contact you, such as email, phone and chat.

If you follow the above strategies for selling your domain name, you will significantly increase your odds of obtaining the best price possible. Also, many of the strategies presented are helpful when buying a domain name.

Russia Number One In Weapons Export

The report "Weapons supplies to developing countries 1998-2005" published by the research service of the USA Congress contains data claiming that last year Russia became number one in weapons export to developing countries with the total sum of contracts contracts adjusted to 7.1 billion dollars. According to this document, excerpts from which were published with comments in The New York Times, Moscow beat Washington, which took the third position with its 6.2 billion dollars contracts. The second position belongs to France: it sold weapons on 6.3 billion dollars, according to the US Congress.

However, several facts of the "sensational" document cause serious doubts. First of all, data provided by the US Congress do not gee with the information spread in the beginning of the year by the federal commission of military-technical cooperation of Russia where the volume of Russian weapons export in 2005 was estimated 6.126 billion dollars. The sum can be considered record as in recent years Russian exporters could hardly reach the verge of 5 billion dollars. It seems logical to be interested in clarification of the 1 billion difference in the Congress and the Federal commission data.

Washington did not beat about the bush to find an explanation of the difference mentioned above: their comments indicated the fact that they also included Russian export of several land anti-aircraft defense systems (zenith-missile complex TOR-M1) to Iran. At the same time the report did not emphasize the fact whether Moscow had already supplied the systems to Teheran or not. It only informed that the affair cost 700 thousand dollars and that apart from zenith-missile complex Russia had also sold 8 air tankers to Iran. Ides, Washington included Russian help concerning Teheran's military equipment modernization into the volume of Russian supplies to Iran. In two words, Russia became "champion in weapons export" through not only India and China, but also Iran.

And this is the second point that causes hesitations about objectivity and relativity of the analysis held by the research service of the Congress. Warlike equipment and arms export has always been quite a politically loaded issue. While marking Russian success in weapons trade the US report clearly observes upon their backsliding from leading positions in this chart. Interestingly, this happens straight ahead to the Congress elections. The report claims that the States have lost a significant share of the weapons market since 2004. That year the US did 9.4 billion dollars on weapons trade while Russia did only 5.4, and now Russia is one billion dollars ahead. The conclusion which is likely to get into many people of electional age minds is quite predictable: to vote for democrats who can bring back our leadership in weapons trade which means new jobs, new earnings …

It is necessary to mention that weapons export matters in the States are not on the decline. In 2005 the US income from weapons trade was inconsiderably smaller than in 2004, coupled, Russian achievements in this sphere do not look that impressive in comparison with just one of the US contracts – 7 billion dollars contract with Turkey. Moreover, the US also provides NATO countries with weapons as well, while the mentioned market zone is deadly closed for Russian weapons suppliers.

The General assembly of NATO has recently made a decision to organize a special group to work out new international regulations concerning weapons trade and export. Experts hope that after the regulations come into force data on the achievements in this sphere will be more truthful and reliable.

Source:

http://www.rian.ru

Translation: Lavrentyeva Natalya

What Software Should I Use to Create My CD or DVD Artwork?

After recording your album, having it mastered and pressed, you head over to your disc duplication facility's website to place your order. Reading up on the ordering process you notice that you have the option to have artwork printed on the disc face, and can also have tray card and insert art printed. This is a great idea, as it allows you to give your project a more professional look and feel. You can either hire a print designer, who will hopefully already know all of the proceeding information. Or you can have a go at it yourself, utilizing one of the many different graphics creation programs available. If you are choosing to create your own artwork, read on.

There are many different programs out there that can be used to create print artwork. One of the more popular programs is Adobe Illustrator. Adobe Illustrator is a vector based drawing program, available for both PC and Macintosh computers. You could also use CorelDRAW, Paint Shop Pro, or even Adobe Photoshop. I will go into a little bit more detail about what the differences are between some of these programs later on in this article, and why some of them are better suited for print design. Here is a list of 3 terms you should be familiar with before starting your artwork project.

1. Raster Graphics

Raster graphics are also known as bitmap graphics. This form of graphics image is a data file or structure representing a generally rectangular grid of pixels, or blocks of color, on a computer monitor, or other display device. Think of a raster images as a checkers board, with each square (pixel) on the board displaying a different color. This collection of colored dots (pixels), in turn form the full picture. The quality of a raster image is determined by the total number of pixels (resolution), and the amount of information in each pixel. Raster graphics are practical for photographs and photo-realistic images because of the way that they display images. Pretty much all photos you will find on the internet, and all photos you take with your digital camera will be raster images. You may want to use photographs for your CD or DVD's artwork, but you must mind a few certain things:

A. DPI -
I will go into this a bit further in the "DPI" section of this article. In a nutshell, any photograph that you would like to use for print must be 300 DPI (dots per inch) or higher. DPI reiterates the density of pixel information in a photograph.

B. Color Mode -
There are two basic modes of color: RGB and CMYK. All you need to know really is that all print artwork must be created as a CMYK document, as this reflects the colors of ink that a printer uses to recreate your artwork. If you create your artwork as an RGB document, the printed document will most likely shift in color. For more info on this, please refer to my last article. What do you need to start a CD duplication project?

2. Vector Graphics

Also known as geometric modeling, this form of graphic uses geometric primitives such as points, curves, and lines to represent images. Instead of displaying blocks of color to represent a photo vector images readily on set points to determine the outline of an object, using mathematical formulas to determine the course of the lines between set set points. Vector graphics are ideal for simple or composite drawings that do not need to achieve photo-realism. I suggest that you used vector objects for all of your artwork's areas that are not photos.

3. DPI

Dots per inch, (DPI) is the number of individual dots of ink a printer that can produce within a one-inch space. This translates as, the higher the DPI, the sharper image. Although, most commercial printers will tell you that anything over 300DPI would have considered "print-quality". I recommend that you make sure that your artwork is at least 300DPI, with 600DPI being the optimal setting for your artwork.

After all technical mumbo-jumbo, you're probably scratching your head, still unsure of what program to use to create your artwork. The truth is you can use pretty much any graphics program to create your artwork, providing that you correctly set the DPI and color mode of your document. Personally, I usually use a combination of Adobe Photoshop & Illustrator to do all of my print artwork. I edit all bitmap images in Photoshop and create all of my vector content in Illustrator, combining the two in Illustrator. My advice is now that you have the basic background knowledge, experience to figure out what works best for you!