UmarMakhzumi

Hi Mohammad, What do you mean by design and execution marina as pdf? Apologies but I am not familiar with this term. Thanks.

WSalaam, It should work. Have a look at this watch and learn to make sure you are following the right steps. Thanks.

W/Salaam, Free vibrations are vibrations of the structure (or any other thing) that result once the structure is excited and the vibrations are let to die down without additional interference. For example if you have a pendulum at rest, you pick the bob in your hand, move it on one side and let it go. Once you let go the bob, the pendulum vibrates around the initial rest point. The period of vibration is dependent on the length of pendulum (technically the parameter that defines its stiffness) and is independent of the mass of the bob. If you measure the time the pendulum would take even as it slows down to complete a cycle, it is exactly the same. Amazing isn't it. This is an example of free vibrations. Now, forced vibrations are different. In forced vibration, you have a situation where the load producing or causing vibration of structure (or any other thing) is "continuously being applied" at a frequency. An example would be a reciporcating or centrifugal machine sitting on say concrete foundation. Operation of machine would put the foundation in vibration (machine load itself has a frequency which may or may not match with foundation natural frequency) and would force the foundation response under its frequency. The foundation will as a result vibrate based on its stiffness (like pendulum). Another example considering the case of pendulum (so that you can relate) for forced vibrations would be if you put a big fan infront of the pendulum and it vibrates under the wind of fan. Summary: In free vibrations, you disturb a structure and let it vibrate without disturbing it further. In forced vibrations, the structure is continuously being disturbed by a force applied at regular interval. That is why they are called forced vibrations as we are forcing structural response under external cyclic load. Enjoy the attached forced vibrations video as well that shows breaking of a wine glass under sound. Sound waves are what are forcing the glass to vibrate and the frequency of the sound waves has been set so that its close to natural frequency of the glass causing it to resonate and break.

You can also check out use of Project Loading that might have some limited application for your case. http://docs.csiamerica.com/help-files/etabs/Menus/Assign/Frame_Loads/Distributed_Load.htm https://wiki.csiamerica.com/display/kb/Frame+loading Thanks.

Spot on!

WS, There are different ways you can invest in PSX. The two common ones are: 1) By buying mutual funds 2) Open an account with a broker For Investing in mutual funds, you can head to any bank and ask them about what mutual funds they offer. Mutual funds are investment vehicle that allows pool of investors to buy group of stocks bundled in a single fund. Investment in mutual funds suits people who don't want to invest a large amount and would prefer a small percentage of their monthly income go towards investment (5-10% of Salary, You can even go higher or lower). Mutual funds usually have a fees 1-3% that is deducted from any profits. You can read more about investing in mutual funds here: https://www.dawn.com/news/1109126 . Meezan Bank has some very good index tracking mutual funds. You can check them out on their website if they would suit your needs. The second option of opening an account with a broker, requires you to do the trades. This is easy as well but remember to pick a top of the link broker as there is some history of broker fraud. Good brokers are Topline Securities, AKD Securities and any reputable bank that would offer these services. My broker is AKD. Every broker has a minimum capital investment requirement and charges they would deduct per stock trade. I think AKD requires a minimum investment of RS 100,000 (http://www.akdtrade.com). Once you open an account with a broker, you should also sign up for CDC. CDC is a body that protects investors incase of broker fraud. If you are signed up with CDC, your broker is required to copy CDC on each transaction. That means that CDC has a record of your investments and all investments in shares are safe. Anyway, when you invest by opening an account with a broker, you directly buy shares or sell them through your broker. They will provide you with a software which allows you to do that. It is very simple. In order to know which shares to buy, you will need to spend time to know the business in which you are investing. I can elaborate on that later after you have opened an account. Here are a few rules that I have invented that can help you with stock investment: Rule number 1 is that stock are only profitable if you invest your savings that you would not need to at least 3-5 years. If you have money set aside and you think that you will need that money in an year, don't invest in stocks. The reason being that stocks are very volatile and risky. It takes time for an investment to grow and produce returns. If your time frame is small, you are speculating the market not investing. Rule number 2 is that you can only make money in stocks if you buy them at a reasonable price. In order to know what a reasonable price is, you will need to look up company's financial statement and go through the numbers. It is very hard to make money in stocks if you don't buy them at a decent price. Rule number 3 is that never give your money to someone else to invest in stocks. If someone tells you that they would provide you with a guaranteed return of X thousands Rupees per month, that is a ponzi scheme. Stay away or you will lose your hard earned money. This rule is very important and applies to everyone esp people you have known for a long time. Rule number 4 is that never borrow money to invest in stocks. This is very dangerous. Borrowing to invest in stocks is pure speculation. Rule number 5 is read the book called The Intelligent Investor by Benjamin Graham. So if you follow the rules you will get a good return. I have even got 100%+ returns on some investments. The key is to keep reading stuff and do it yourself. Let me know should you have additional questions. Thanks.

Thanks for the typo correction there.

Can you please share how the load has been applied to the 1-bay, 3 story masonry infilled frame? Also, what is "openness" ? It would be beneficial to see the deflected shape at different time steps. In general principle the response of a frame modelled with masonry struts should be similar to that of a braced bay. I can't think of a reason why the col shear is negative in elastic region other than application of load that causes negative shear and then with time the load changes and so does shear. It might be beneficial to look at how load is being applied with time and we can discuss it.

Dear All, The forum has been recently upgraded with tons of new features. Please take a minute and explore the new items. Your feedback is much appreciated. You can check out the following thread that summarizes biggest changes to forum. Thanks.

W/s Waqas, What is the angle of the backfill with the horizontal? After I know that I might be in a better position to comment in detail but as a matter of general approach, since backfill pressure on the wall is applied considering soil as a fluid (Gamma*H), the lateral load due to backfill should stay the same as your maximum height stays the same. This is my opinion and if someone else had a different one, I would love to hear that as well. The image below explains the same thing. Also what is the utilization of this wall. I mean why are you making it. What land use would be for the area on the non-backfilled face of the wall? You have mentioned that the wall is 30 feet high. Is the backfill slope lowest point 30 feet as well or it goes much further below? Depending on that, there might be an alternate sliding plane.

I was browsing through my archives are noticed a bunch of articles written by NICEE (National Information Centre of Earthquake Engineering (NICEE) was established in IIT Kanpur with the mandate to empower all stakeholders in the building industry in seismic safety towards ensuring an earthquake resistant built environment. NICEE maintains and disseminates information resources on Earthquake Engineering. It undertakes community outreach activities aimed at mitigation of earthquake disasters. NICEE’s target audience includes professionals, academics and all others with an interest in and concern for seismic safety). The articles are free to publish as long as original content stays unchanged. These articles are good for fresh structural engineers and Civil/ Structural Engineering Students. The best thing about them is that they are only 2 pages and full of images. It literally takes less than 5 min to go through each. EQTip19.pdf EQTip20.pdf How architectural features effect buildings.pdf How buildings twist during earthquakes.pdf How do Beam-Column Joints in RC Buildings Resist Earthquakes.pdf How do Brick Masonry behave during Earthquake.pdf How do Columns in RC Buildings Resist Earthquakes.pdf How do Earthquake Affect Reinforced Concrete Buildings.pdf How Flexibility of Buildings affect their earthquake response.pdf How the ground shakes.pdf How to make building ductile for Good Seismic Performace.pdf How to make Stone Masonry Buildings Earthquake Resistant.pdf How to Reduce Earthquake Effects on Buildings.pdf What are magnitudes and intensity.pdf What are seismic effects on structures.pdf What causes earthquake.pdf What is seismic design philosophy of Buildings.pdf Why are Buildings with Shear Walls Preferred in Seismic Regions.pdf Why are horizontal bands necessary in masonry buildings.pdf Why are Open Ground Storey Buildings Vulnerable in Earthquakes.pdf Why are Short Columns more Damaged During Earthquake.pdf Why is vertical reinforcement required in masonry buildings.pdf Why should Masonry Buildings have simple Structural Configuration.pdf

Waqar, This is a very good idea. I would suggest creating an event using Calendar. In that way everyone on the forum be aware of this. Thanks.

Right now there is one position open for SEFP FB Page but I would like it to be assigned to any of our female member. This would be to keep gender equality. The mentoring coordinator post is still open and I need help formatting guidelines and setting up the program.

Forgot to add that I have assigned a few colours to roles as well. Admins and Mods are red

Correct. My reply was generic. I just wanted to highlight that the provision should be used with a grain of salt.

Dear All, I have just finished modifying a bunch of stuff related to member roles and I am very excited to announce it. There are some new member roles that have been created: 1) SEFP Associate As you know that I have been requesting help with a number of stuff on SEFP and there are very generous people who have volunteered. To recognize their effort, I have created this role. An example is @Saad Pervez, who is doing an excellent job running our Social Media pages. From now onwards, you will find him assigned to SEFP Associates. Thanks Saad for your help. 2) SEFP Contributor There are a few members who have been with us through thick and thin. Because, they have regularly answered questions and contributed to forum by not only providing information but their engineering judgement, this role has been created in recognition of their efforts. @Ayesha has been assigned to this and we look forward to add more members to their club. 3) SEFP VIP @EngrUzair deserves this without any question. He is the most senior member of the forum providing invaluable support. Not only this but he has also been a teacher at our beloved Alma Mater. I have created this category in recognition to his efforts. We "might" be adding very few people to this role in upcoming years. 4) Moderators and Super Moderators Our current staff consists of @waqar saleem, @Rana and @BAZ. @Rana and @BAZ have global moderation over the forum and @waqar saleem is currently moderating all the technical sections. They all are doing a great job and I am very thankful them. Because of overall moderation assignment, I have split moderators in Super Moderator and Moderators. Supermods might also get portion of Admin rights over coming years. I have a plan for that but nothing set in stone. Like always, please provide your feedback and let me know what else should be done/ undone. Thanks.

Its debatable but a very good point to highlight. Good.

Great share Waqar.

True but it would also depend on how thick the member is. For thin members (lets not get into how thin is thin) two layers top and bottom might be more than sufficient.

That is correct. Just ask your geotechnical engineer to do that for your. UBC 1636.2 defines soil profile type based on shear wave velocities. For types SC and SD, you can directly use average field standard penetration resistance as defined in 1636.2.2. For shear wave velocity (the question by OP), I am dead sure that SPT correlation can be used. Here is the history why: I was recently involved in assessment of several centrifugal stiff shaft pumps. In order to calculate the dynamic response of foundation, dynamic soil properties like shear wave velocity, dynamic modulus are required. The pumps were pretty old. While looking at the geotechnical reports for the pump foundation, I noticed that the geotechnical engineer had used SPT N correlations to do calculate soil shear wave velocity. So I know, they can use that. So ask your geotechnical guy to furnish you that info. Thanks.

I would just add that in choosing suitable locations for structural walls, the following additional aspects should be considered: 1. Locate the walls at the perimeter or periphery of the building to get the best torsional resistance. 2. Locate your walls so that they carry as much gravity load to the foundations as possible. This would reduce uplift forces in the foundation and also would reduce flexural reinforcement demand in the wall. Thanks.

I think members should be free. Guests should be exposed to it. Anyway, the margins are very thin. I was actually surprised to see that revenue are even smaller than what I thought but nonetheless, it doesn't hurt to put some for guests.

Thanks for the kind words Waqas.

Did you guys know that WTC Twin Towers (even demolished) are of significant importance to Structural Engineering as they were the first buildings to have a lot of new structural innovations incorporated. One example is that they were the fist structure outside of the military and the nuclear industries designed to resist the impact of a jet airliner. The structural engineers that designed the WTC Twin Towers think that the fire-resistive systems, however, did not and could not have contemplated the subsequent fire fueled by thousands of gallons of jet fuel. You can read their complete statement at: http://www.lera.com/world-trade-center-sep-11-2011- A listing of the innovations incorporated into the World Trade Center is over long. Still, listing just a few of the ideas and innovations conceived and developed by LERA: - The tubular framing system for the perimeter wallresisting all of the lateral forces imposed on the building; - The introduction of the outrigger system; structurally linking the outside wall to the services core; - The prefabrication in structural steel to a degree never before achieved; - The use of the boundary-layer wind tunnel for predicting both steady-state and dynamic forces on structure and on glazing, and for developing the dynamic component of wind-induced structure motion; - Motion-simulators to determine acceptable levels of wind-induced structure motion; - The viscoelastic damping system, effectively dissipating the dynamic component of building motion; - The development of a theory to predict the breakage rate of glass under the dynamic forces of the wind; - The development of a theory to predict stack action and both temperature- and wind-induced airflow within a high-rise building; - The concept of the fire-rated shaft Wall partition system, which partition has replaced masonry and plaster walls… at the time the standard enclosure for elevators, stairs, duct shafts and the like. Source: 1) http://www.lera.com/world-trade-center-

All, Starting today, I would be experimenting with some advertisement options on the forum. That would include making ads visible to guests (non-registered members) only. It would also help me estimate the amount this site can pay for itself. Right now, the estimated projections are very low in-terms of revenue (5-10% max of yearly budget). Members would always see a clean forum (no ads). Guests, however would be subjected to Ads. Any suggestions or ideas are welcome. Thanks.