FINITE ELEMENT MODELING OF REINFORCED CONCRETE BEAM COLUMN JOINTS RETROFITTED WITH GFRP WRAPPING

Recent earthquakes have demonstrated that most of the reinforced concrete 

structures were severely damaged during earthquakes and they need major repair works. 

Beam column joints, being the lateral and vertical load resisting members in reinforced 

concrete structures are particularly vulnerable to failures during earthquakes. The existing 

reinforced concrete beam-column joints which are not designed as per code IS 

13920:1993 must be strengthened since they do not meet the ductility requirements. The 

finite element method (FEM) has become a staple for predicting and simulating the 

physical behavior of complex engineering systems. The commercial finite element 

analysis (FEA) programs have gained common acceptance among engineers in industry 

and researchers. The details of the finite element analysis of beam column joints 

retrofitted with glass fiber reinforced polymer sheets (GFRP) carried out using the 

package ANSYS are presented in this paper. Three exterior reinforced concrete beam 

column joint specimens were modeled using ANSYS package. The first specimen is the 

control specimen. This had reinforcement as per code IS 456:2000. The second specimen 

which is also the control specimen. This had reinforcement as per code IS 13920:1993. 

The third specimen had reinforcement as per code IS 456:2000 and was retrofitted with 

glass fiber reinforced polymer (GFRP) sheets. During the analysis both the ends of 

column were hinged. Static load was applied at the free end of the cantilever beam up to a 

controlled load. The performance of the retrofitted beam-column joint was compared 

with the control specimens and the results are presented in this paper. 

Key words: Beam column joint, Retrofitting, FRP sheets. The techniques of using fiber sheets for strengthen the beam column joints have a number of favorable characteristics such as ease to install, immunity to corrosion and high strength. The simplest way to strengthen the joints is to wrap fiber sheets in the joint 

region in two orthogonal directions. Many fiber reinforced polymer sheets are available the market for strengthening reinforced concrete members .Glass fiber reinforced 

polymer sheets are commonly used for retrofitting the structural elements.

The beam column joint considered for analysis consists of a cantilever portion and 

column portion as shown in Figure 1.a and Figure 1.b. The column had a cross section of 

200 mm x 200 mm with an overall length of 1500 mm and the beam had a cross section 

of 200 mm x 200 mm and the length of the cantilevered portion was 600 mm. The control 

specimens were designated as C1 and C2. C1 had reinforcement as per code IS 456-2000 

and C2 had reinforcement as per code IS 13920-1993. The specimen retrofitted with glass 

reinforced polymer sheet was designated as C3 which had reinforcement as per code IS 

456-2000. The column portion was reinforced with 4 numbers of 12mm diameter Fe 415 

rods and the beam portion was reinforced with 2 numbers of 16 mm diameter Fe 415 rods 

each in the tension and compression zones. The lateral ties in the columns of the 

specimens C1 and C3 were 6 mm diameter Fe 250 bars with the spacing of 180 mm c/c 

as per code IS 456:2000, clause 26.5.3.2(c). Beam had vertical stirrups of 6 mm diameter 

Fe 250 bar at 120 mm c/c as per code IS 456:2000, clause 26.5.1.6. The development 

length of the tension and compression rods in beam were also provided as per clause 

26.2.1 of code IS 456:2000. For the specimen C2, the lateral ties in the columns consisted 

of 8 mm diameter Fe 415 bar at 75 mm c/c for the central distance of 1100 mm as per 

code IS 13920:1993, clause 7.4.6 and 6mm diameter Fe250 bars at 100 mm c/c for the 

remaining length of the column. Beams had vertical stirrups of 6 mm diameter Fe 250 bar 

at 40 mm c/c. up to a distance of 340 mm from the face of the column as per code IS 

13920:1993, clause 6.3.5 and 6 mm diameter Fe250 bar at 80 mm c/c for remaining 

length of the beam. The development length of the beam rods were also provided as per 

code IS 13920:1993, clause 6.2.5. M25 grade concrete was adopted. 13920:1993 

Meshing was done for both control and retrofitted specimens using ANSYS. Both ends of 

the column were hinged. The concrete was modeled using Solid 65 element. The 

reinforcement was modeled using Link 8 element. The wrapping was modeled using 

Solid 45 element. The static load was applied at the free end of the cantilever beam at a 

regular load interval of 5 kN for the control and retrofitted reinforced concrete beam 

column joint models. The performance of the retrofitted beam column joint specimen was 

compared with the control beam-column joint specimens

NON LINEAR MODELING OF THE BEAM-COLUMN JOINTS 

Non linear analysis was done for three beam column specimens using the 

software ANSYS. A transverse static was applied at the free end of the beam to develop a 

bending moment at the joint. The load was increased in steps till a controlled load of 22 

kN. The deflection at the free end of the cantilever beam was noted. The deflections of 

the specimen C1 were found to be 12.5 mm for the load of 15 kN, 35 mm for the load of 

20 kN, and 56 mm for the load of 22 kN. The same procedure was repeated for the 

specimen detailed as per code IS 13920-1993 and for the retrofitted specimen. Figure 3a, 

Figure 3b, and Figure 3c show the typical views of the deflected control and retrofitted 

specimens. Figure 4 shows the load deflection curve for the control and retrofitted 

specimens. Table 1 shows comparison between the deflections and energy absorption 

capacity of the control and retrofitted specimens. 

DISCUSSION OF THE RESULTS 

 It can be found from the Table 1 that the deflection of the beam column joint 

specimen detailed as per code IS 13920-1993 is 19.64 % less than that of the specimen 

detailed as per code IS 456-2000 and deflection of the beam column joint specimen 

retrofitted with glass reinforced polymer sheet was 42.85 % less than that of the 

specimen detailed as per code IS 456-2000.The energy absorption capacity of the 

specimen beam column joint specimen detailed as per code IS 13920-1993 is 15.93 % 

more than that of the specimen detailed as per code IS 456-2000 and energy absorption 

capacity of the beam column joint specimen retrofitted with glass reinforced polymer 

sheet was 34.22 % more than that of the specimen detailed as per code IS 456-2000. 

CONCLUSIONS 

 Based on the ANSYS modeling and analysis carried out on the control and retrofitted beam 

column joint specimens using GFRP sheets, the following conclusions were drawn: 

• The deflection of the beam column joint specimen detailed as per code IS 13920-1993 

was found to be 19.64 % lower than that of the specimen detailed per code IS 456-

2000. 

• The deflection of the beam column joint specimen retrofitted with GFRP sheet reduced 

the deflection about 42.85 %.when compared with the deflection of specimen detailed 

as per code IS 456-2000. 

• The energy absorption capacity of the beam column joint specimen detailed as per code 

IS 13920-1993 was found to be 15.93 % higher than that of the specimen detailed per 

code IS 456-2000. 

• The energy absorption capacity of the beam column joint specimen retrofitted with 

GFRP sheet increased about 34.22 %.when compared with the energy absorption 

capacity of specimen detailed as per code IS 456-2000.

Will Digital Networks Ruin Us?

With unemployment seemingly stalled out at around 7 percent in the aftermath of the Great Recession, with the leak of thousands of National Security Agency documents making news almost daily, with the continuing stories about the erosion of privacy in the digital economy, “Who Owns the Future?” puts forth a kind of universal theory that ties all these things together. It also puts forth some provocative, unconventional ideas for ensuring that the inevitable dominance of software in every corner of society will be healthy instead of harmful.

Lanier has an unusual authority to criticize the digital economy: He was there, more or less, at the creation. Among (many) other things, he founded the first company to sell virtual reality products. Another of his start-ups was sold to Google. As a consultant, he has had assignments with “Wal-Mart, Fannie Mae, major banks and hedge funds,” as he notes in “Who Owns the Future?” But unlike most of his fellow technologists, he eventually came to feel that the rise of digital networks was no panacea.

On the contrary: “What I came away with from having access to these varied worlds was a realization that they were all remarkably similar,” he writes. “The big players often gained benefits from digital networks to an amazing degree, but they were also constrained, even imprisoned, by the same dynamics.”

Over time, the same network efficiencies that had given them their great advantages would become the instrument of their failures. In the financial services industry, it led to the financial crisis. In the case of Wal-Mart, its adoption of technology to manage its supply chain at first reaped great benefits, but over time it cost competitors and suppliers hundreds of thousands of jobs, thus “gradually impoverishing its own customer base,” as Lanier put it to me.

Joe Nocera

FRED R. CONRAD / THE NEW YORK TIMES

The N.S.A.? It developed computer technology that could monitor the entire world — and, in the process, lost control of the contractors it employed. As for Facebook, Google, Twitter, Amazon et al., well, in Lanier’s view, it’s only a matter of time before their advantages, too, disintegrate.

There are two additional components to Lanier’s thesis. The first is that the digital economy has done as much as any single thing to hollow out the middle class. (When I asked him about the effect of globalization, he said that globalization was “just one form of network efficiency.” See what I mean about a universal theory?) His great example here is Kodak and Instagram. At its height, writes Lanier “Kodak employed more than 140,000 people.” Yes, Kodak made plenty of mistakes, but look at what is replacing it: “When Instagram was sold to Facebook for a billion dollars in 2012, it employed only 13 people.”

Which leads nicely to Lanier’s final big point: that the value of these new companies comes from us. “Instagram isn’t worth a billion dollars just because those 13 employees are extraordinary,” he writes. “Instead, its value comes from the millions of users who contribute to the network without being paid for it.” He adds, “Networks need a great number of people to participate in them to generate significant value. But when they have them, only a small number of people get paid. This has the net effect of centralizing wealth and limiting overall economic growth.” Thus, in Lanier’s view, is income inequality also partly a consequence of the digital economy.

It is Lanier’s radical idea that people should get paid whenever their information is used. He envisions a different kind of digital economy, in which creators of content — whether a blog post or a Facebook photograph — would receive micropayments whenever that content was used. A digital economy that appears to give things away for free — in return for being able to invade the privacy of its customers for commercial gain — isn’t free at all, he argues.

Lanier’s ideas raise as many questions as they answer, and he makes no pretense to having it all figured out. “I know some of this will turn out to be wrong,” he told me. “But I just don’t know which part.”

Still his ideas about reformulating the economy — creating what he calls a “humanistic economy” — offer much food for thought. Lanier wants to create a dynamic where digital networks expand the pie rather than shrink it, and rebuild the middle class instead of destroying it.

“If Google and Facebook were smart,” he said, “they would want to enrich their own customers.” So far, he adds, Silicon Valley has made “the stupid choice” — to grow their businesses at the expense of their own customers.

Lanier’s message is that it can’t last. And it won’t.

Have we reached the end of globalization?

At the start of 2014, let's take a look at one of the great trends of the last century. You could be sitting in Chicago, Illinois right now, but your TV was probably made in Japan, your sneakers were likely manufactured in China and your coffee might be from Kenya. Globalization impacts every single thing around us. So here’s the big question: have we reached the end of globalization?

For much of the last thirty years there has been a steady trend in commerce: global trade has expanded at about twice the pace of the global economy. For example, between 1988 and 2007, global trade grew on average by 6.2 percent a year according to the World Trade Organization. During the same period, the world’s GDP was growing at nearly half that pace: 3.7 percent.

But a strange thing has taken place in the last two years. Growth in global trade has dropped dramatically, to even less than GDP growth. The change leaves one wondering: has the incredible transfer of goods around the world reached some sort of pinnacle? Have we exhausted the drive toward ever-more-globalization?

It's a fascinating thesis. The world has seen historic developments in the last few decades: the internet, China's opening up, the rise of emerging markets, fast and cheap travel…all of these trends led to a massive acceleration in global trade.

But have those trends peaked? Could the next big invention, say, 3-D printers, end the need for more and more trade? Imagine a world where you need a new faucet in your restroom. Instead of going to the local store that sells faucets made in China (which contributes to global trade) now you just print out your own faucet, sitting at home or at a local store. Are people also getting more interested in local products compared to global brands.

Joshua Cooper Ramo points out in an essay in Fortune that localism is on the rise – local banking, local manufacturing, and even local sourcing for food and restaurants. Is this simply a pause or could it be more than that? The answer will depend on politics.

The last time the world saw a consistent period where the growth of global trade lagged behind global growth was in the 1920s, 30s, and 40s. One factor was the rise in protectionist policies - as a response in many cases to the Great Depression and the disruption of the gold standard. At one point, under what was known as the Smoot-Hawley tariff, the United States government began imposing import duties of around 60 percent. The move was aimed at protecting domestic farmers, but instead, it exacerbated the depression. It led to a steep drop in trade, and a wave of counter protectionist measures by other countries.

The world has learned its lessons from the Great Depression. But perhaps not as well as it should have.

According to the independent think tank Global Trade Alert, we’re in the midst of a great rise in protectionism. In the 12 months preceding May 2013, governments around the world imposed three times as many protectionist measures than moves to open up. Anti-trade policies are at their highest point since the 2008 financial crisis. According to the Petersen Institute, the rise of these measures cost global trade 93 billion dollars in 2010.

There might be some good news on this front. Last month, the World Trade Organization passed a deal to cut red tape in customs. It’s a small start, and there is a lot more to accomplish. Globalization and trade have produced huge benefits for people, especially the poor, who have been able to make their way out of poverty in a faster growing and more connected global economy. But globalization won’t continue by accident or stealth – politicians will have to help make it happen.

CHAVITTU NADAKAM (ചവിട്ടുനാടകം)

Why are venomous organisms like snakes unaffected by their own venom?

Usually venoms act by binding to the receptors present on the surface of the muscle cells on the victim thereby blocking the communication between the nerve cells and muscle cells in the victim.

When the toxin is already bound to the receptor, the natural neurotransmitter acetylcholine can no longer bind to the receptor as there were no free receptors left available by the toxins present in the venom. This blockage cause paralysis in the victim and in the worst case leads to death based on the nature of the venom. The receptors present on the mice and the humans are different from that of the venomous creatures like snakes. This difference prevents the venomous creatures’ venom binding to its receptors.

In snakes, sugar molecules cover the amino acid residues of the receptors thus protecting the binding of its own venom. However, the amino acid residues on the receptors are the same in the all the organisms only the clouding of the residues by sugar molecules make the venomous organisms resistant to their own venom.

Researchers have found that only two groups of animals, snakes and mongooses have sugar molecules on their receptors. The different types of venom attack different tissues in different ways, so a species of snake can ever become completely immune to the venoms of every other species of venomous snakes found in nature. Snakes are immune to the venom that most species of their own species. For example, in an attempt to stimulate or resist copulation, snake species bite one another during sexual combat. Snakes engage in sexual combat display immunity to the venom of their own species which is a must for their survival.

Other mechanisms that are protective for the snakes are as follows: Venom glands of the snakes make venom and specialized cells lining the venom gland protect the venom getting into their blood stream. As long as the venom does not get into the blood stream, it is safe for the animal.

How to Kiss - ten tips

There are kisses for just about every emotion and occasion — the greeting kiss on the cheek, the maternal kiss on the forehead, an affectionate kiss on the lips, the kiss of death — but on those certain occasions when you want to communicate passion and maybe lust, not just any kiss will do. You need a fiercely passionate kiss. If done incorrectly, these kisses can turn out being gross or sloppy, but when performed with skill and feeling, there is no greater expression of love.

1.Make sure your breath is minty fresh and clean. Naturally you practice good oral hygiene, but if you have any doubts about your breath, take a breath mint shortly before the kiss. Make sure to finish the mint or gum before you lock lips.

• Be careful, as some mints may leave a bad aftertaste and make your breath worse. Water is the best bet! Leaves you no aftertaste, and freshens your mouth and does not leave you thirsty.

2.Approach the kiss with confidence. Try to kiss their cheek so they turn their head your way. Once you've chosen the right moment to kiss someone, there's no turning back, especially if it's your first time kissing that particular person. Be decisive and confident. If the person doesn't want the kiss, he or she will let you know, but until then, act as though you're a pro.

3.Lean in and tilt your head slightly. Leaning in signals that you want to kiss the person, and tilting your head prevents crushing your nose against the other person's.

4.Don't try to thrust your tongue in your partner's mouth right away. Simply press your lips against theirs. Close your eyes as you do so to heighten the intimacy and to avoid looking at the pores on your partner's nose. Imagine your eyes are being controlled by a dimmer switch.

5.Open your lips slightly. Once the kiss is accepted, try opening your lips slightly. If the other person follows suit, try slightly varying the openness of your lips (both more and less open) throughout the kiss. You may wish to explore the person's lips and tongue a bit with the tip of your tongue. There are no rules; just try to make your motions smooth

6.Consider the French Kiss. As the kiss progresses, you may want to try French kissing, in which you insert your tongue lightly into your partner's mouth and let it dance with your partner's tongue.

7.Try some necking. If things are going well, consider spicing it up a bit by moving your head down to kiss and lightly nibble your partner's neck

8.Keep your arms busy. You seldom, maybe never, see a great kiss in which the participants just let their arms dangle at their sides. At the very least, embrace your partner and gently pull him or her to you.

• You can also run your hands through your partner's hair; or caress his or her back, sides, or other parts of the body. Wrapping your arms around your partner can also be a big turn-on!
• Where you put your hands should be determined by the status of your relationship, your desires, and your partner's signals, whether spoken or communicated non-verbally.

9.Try a ten-second kiss. Some find that a kiss of at least ten seconds in duration will passionately bond two people more than a shorter kiss. Just hold the kiss for longer, regulating your breathing and keeping your eyes closed.

10.try kissing in a comfortable position and romantic area. This will make the kiss last longer and even might start a French kiss which is a tongue to tongue kiss.

What is a cookie?

Cookies are usually small text files, given ID tags that are stored on your computer's browser directory or program data subfolders. Cookies are created when you use your browser to visit a website that uses cookies to keep track of your movements within the site, help you resume where you left off, remember your registered login, theme selection, preferences, and other customization functions.The website stores a corresponding file(with same ID tag)to the one they set in your browser and in this file they can track and keep information on your movements within the site and any information you may have voluntarily given while visiting the website, such as email address.

Cookies are often indispensable for websites that have huge databases, need logins, have customizable themes, other advanced features.

Cookies usually don't contain much information except for the url of the website that created the cookie, the duration of the cookie's abilities and effects, and a random number. Due to the little amount of information a cookie contains, it usually cannot be used to reveal your identity or personally identifying information.However, marketing is becoming increasingly sophisticated and cookies in some cases can be agressively used to create a profile of your surfing habits.

There are two types of cookies: session cookies and persistent cookies. Session cookies are created temporarily in your browser's subfolder while you are visiting a website. Once you leave the site, the session cookie is deleted. On the other hand, persistent cookie files remain in your browser's subfolder and are activated again once you visit the website that created that particular cookie. A persistent cookie remains in the browser's subfolder for the duration period set within the cookie's file.

A cookie is a small file of letters and numbers downloaded on to your computer when you access certain websites. Like virtual door keys, cookies unlock a computer's memory and allow a website to recognise users when they return to a site by opening doors to different content or services. Like a key, a cookie itself does not contain information, but when it is read by a browser it can help a website improve the service delivered.

Cookie files are automatically lodged into the cookie file - the memory of your browser - and each one typically contains:

• The name of the server the cookie was sent from
• The lifetime of the cookie
• A value - usually a randomly generated unique number

The website server which sent the cookie uses this number to recognise you when you return to a site or browse from page to page. Only the server that sent a cookie can read, and therefore use, that cookie.

A cookie is a text-only string of information that a website transfers to the cookie file of the browser on the hard disk of computers so that the website can remember who you are.

A cookie will typically contain the name of the domain from which the cookie has come, the "lifetime" of the cookie, and a value, usually a randomly generated unique number. Two common types of cookies are used on most websites-session cookies, which are temporary cookies that remain in the cookie file of your browser until you leave the site, and persistent cookies, which remain in the cookie file of your browser for much longer (though how long will depend on the lifetime of the specific cookie).