Engr. Onyema Media- Page

25/01/2024

TYPES OF BRIDGES!

22/01/2024

For Civil Engineering PDF file....

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30/11/2023

Cantilever Bridge and Pier
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18/11/2023

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17/11/2023

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12/11/2023

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16/09/2023

https://singingfiles.com/show.php?l=0&u=1685024&id=50229

12/09/2023

PROPERTY AVAILABLE FOR SALE (Distressed Sale)

Landed Property (40plots)

Amount: 4,000,000(per plot)

Location: Porthartcourt

Good Access Road ( Tarred )
100% Dry land.

Good for estate/ plaza/ factory.

Call For More Info/ inspection:
08160751017 / 09060101710

10/09/2023

The Complete Guide to the Major Parts of an Excavator
Read more: https://bit.ly/3PuRN74

1. Boom: The long, vertical arm of the excavator that extends upward and outward.

2. Stick (or Arm): The part that connects the boom to the bucket or attachment, allowing it to extend and retract.

3. Bucket: The attachment at the end of the stick used for digging and scooping.

4. Cabin (or Operator's Cab): The enclosed compartment where the operator sits and controls the excavator.

5. Tracks (or Wheels): The undercarriage of the excavator, which can have either tracks like a tank or wheels for mobility.

6. Hydraulic System: The system that powers the movement of the excavator's parts, including the boom, stick, and bucket.

7. Counterweight: A heavy weight located at the rear of the excavator to balance the weight of the front-end attachments.

8. Engine: The power source of the excavator that drives the hydraulic system and other components.

9. Swing Gear: Allows the excavator to rotate or "swing" on its base.

10. Blade: A blade attachment at the front of some excavators, used for leveling and stabilizing the machine.

11. Track (or Wheel) Motors: These drive the tracks (or wheels) to move the excavator.

12. Fuel Tank: Stores fuel for the excavator's engine.

13. Cooling System: Keeps the engine and hydraulic components at the correct operating temperature.

14. Control Levers (or Joysticks): Used by the operator to control the movements of the excavator.

15. Auxiliary Hydraulic Ports: Allows the connection of various hydraulic attachments such as hydraulic breakers or thumbs.

16. Exhaust System: Routes engine exhaust gases safely away from the operator and surroundings.

17. Undercarriage Rollers and Idlers: Rollers and idlers that support and guide the tracks (in track excavators).

18. Sprockets: Drive the tracks by engaging with the track links (in track excavators).

06/09/2023

2 switch 2 light wiring

06/09/2023

PLUMBING SUPPLY & VENT DIAGRAM

29/08/2023

How would you, as a Structural Engineer, handle a situation where the diameter of Reinforcement on a construction site has been compromised, such as 25mm diameter reduced to 22mm, 20mm to 18mm, 16mm to 14mm, 12mm to 10.5mm, and 10mm to 8mm, even though the Reinforcement on-site has a higher Fy of 500N/mm² than the designed Fy of 460N/mm²? What factors would you consider in making an informed decision, and what actions would you take to ensure that the final structure meets the required standards and can withstand the intended loads and stresses?

My opinion about this:

If I was the Structural Engineer on the project, I already know the implication of the reduced diameter on my Analysis and the solution is to provide more area of steel to the critical members of the structure. For example, if a beam was initially specified to have 6T25, I'll give instructions for them to increase it to 7T25.

Judging from experience, decisions like this might be hard to make on a project due to variation may occur. You'll be challenged by the Project Manager or the Client or any other affected party on the construction team as to why you need to be increasing the bars differently from what was in your proposed Structural drawing.

They might even as well ask you that *"why do you have that steep difference when the Reinforcement diameters is only deficit by ≤ 3mm, they can further bolster their argument by stating that the Strength of the steel on site is higher than the one you used to design, shouldn't that be a plus for you?"*

So if you really understand why you've asked them to increase the number of rebars in those Structural members, to explain to them will be easier.

For those that do not understand why we need to increase the area of steel even though the Steel strength is higher than the designed one?

It's simple, it's because a change in diameter has a more significant impact on the load-carrying capacity and stability of a structure than a change in yield strength. This is because the diameter determines the cross-sectional area of the reinforcement, which is directly proportional to its load-carrying capacity. For further clarity, you can check the formulas in your design process, compare the effects of each parameters like the example below.

Beam section: 450 x 225
Fy = 460N/mm²
Fcu = 20N/mm²
After loading Analysis,
M = 110KNm
d = 417mm

k = (110x10⁶)/(20x225x417²)
= 0.140 < 0.156
Compression steel not required
La = 0.81, z = 0.81x417 = 337.77

As req = (110x10⁶)/(0.95x460x337.77)
As req = 745.23mm²

As prov. = 804mm² (4T16)

Let's check if Fy = 500N/mm²

As req = (110x10⁶)/(0.95x500x337.77)
As req if Fy is 500N/mm² = 685.61mm²
Same Area of steel will be provided as before. (804mm²) 4Y16

Now, let's check if 14mm diameter can be used to replace it since the Fy has been increased.

As prov. on site = (πd²/4) x (number of bars)
diameter, d = 14mm² from the hypothetical question.

As prov. on site = 615.75mm² which very lesser than the Area of steel required (685mm²)

Hence, your request for increment of Number of bars has been justified!

And for the second scenario when the Diameter of steel is intact but the strength is lesser than the one you designed with, you might be sharp to reject the reinforcement but other options to explore is; depending on the Code of practice you used for your design.

For BS8110: if the strength of the Reinforcement on site is ≥ 0.95Fy, then you can still choose to use the Reinforcement.

The 0.95 in the formula for Area of steel required in BS8110 simply means that they have considered 5% Factor of safety for steel strength. (in layman's language, in case the steel strength is lesser by 5% of the Fy, the rebar can still work).

For EC2: if the strength of the Reinforcement on site is ≥ 0.87Fy, then you can still use the Reinforcement.

The 0.87 in the formula for Area of steel required in EC2 simply means that they have considered 15% Factor of safety for the steel grade, (in layman's language, in case the steel strength is lesser by 15% of the designed Fy, you'll still be safe).

But in the hypothetical question that's being discussed, let's use BS8110 which is most common, the designed Fy is 460N/mm², and the provided on site is 440N/mm²

0.95 x 460N/mm² = 437N/mm².

From this check, the provided Fy on site is higher than 0.95Fy, hence, If the material was used, we're still safe.

26/08/2023

Types of Rigs

18/08/2023

13/08/2023

13/08/2023

Retaining Wall Construction

08/08/2023

PUNCHING SHEAR to BS8110:1997
Downloads
https://civilmdc.com/2021/10/04/punching-shear-to-bs81101997/

08/08/2023

30/07/2023

Amazing

28/07/2023

COPIED

_SMARTEST PEOPLE, MEDIOCRE NATION - THE IRONY OF NIGERIA_

_BRITISH Nobel laureate Dorothy Hodgkin once noted that the University of Lagos was one of the v world centres of expertise in her specialist field of chemical crystallography_.

_Ahmadu Bello University Zaria had the first world class computer centre in Africa_.

_The University of Ife had a notable pool of expertise in nuclear physics_.

_Our premier University of Ibadan had an international reputation as a leading centre of excellence in tropical medicine, development economics and the historical sciences_.

_The Saudi Royal family used to frequent UCH for medical treatment in the sixties_.

_The engineering scientist Ayodele Awojobi, a graduate of ABU Zaria, was a rather troubled genius. He tragically died of frustration because our environment could not contain let alone utilise, his talents_.

_Ishaya Shuaibu Audu, pioneer Nigerian Vice-Chancellor of ABU Zaria, collected all the prizes at St. Mary’s University Medical School London. His successor in Zaria, Iya Abubakar, was a highly talented Cambridge mathematician who became a professor at 28 and was a noted consultant to NASA_.

_Alexander Animalu was a gifted MIT physicist who did work of original importance in superconductivity. His book, Intermediate Quantum Theory of Crystalline Solids, has been translated into several languages, including Russian_.

_Renowned mathematician Chike Obi solved Fermat’s 200-year old conjecture with pencil and paper while the Cambridge_ _mathematician John Wiles achieved same with the help of a computer working over a decade_. _After the harsh environment of the 1980s IMF/WB structural adjustment programmes, the Babangida military dictatorship undertook massive budgetary cutbacks in higher education_.
_Our brightest and best fled abroad_.

_Today, Nigerian doctors, scientists and engineers are making massive contributions in Europe and North America. Philip Emeagwali won the 1989 Gordon Bell Award for his work in super-computing_. _Jelani Aliyu designed the first electric car for American automobile giant_ General Motors. _Olufunmilayo Olopede, Professor of Medicine at the University of Chicago, won a McArthur Genius Award for her work on cancer._

_Winston Soboyejo, who earned a Cambridge doctorate at 23, is a Princeton engineering professor laurelled for his contributions to materials research. He is Chairman of the Scientific Advisory Board to the Secretary-General of the United Nations. Washington University biomedical engineering professor Samuel Achilefu received the St. Louis Award for his invention of cancer-seeing glasses that is a major advance in radiology._

_Kunle Olukotun of Stanford did work of original importance on multi-processors. National Merit_ _laureate Omowunmi Sadik of State University of Binghamton owns patents for biosensors technology_. _Young Nigerians are also recording stellar performances at home and abroad_. _A Nigerian family, the Imafidons, were voted “the smartest family in Britain” in 2015_.

_Anne marie Imafidon earned her Oxford Masters’ in Mathematics and Computer Science when she was only 19. Today, she sits on several corporate boards and was awarded an MBE in 2017 for services to science_ _Recently, Benue State University mathematician Atovigba Michael Vershima is believed to have solved the two centuries old Riemann Conjecture that has defied giants such as Gauss, Minkowski and Polya_

_Another young man, Hallowed Olaoluwa, was one of a dozen “future Einstein” awarded postdoctoral fellowships by Harvard University_. _He completed a remarkable doctorate in mathematical physics at the University of Lagos age 21. While at Harvard he aims to focus on solving problems relating to “quantum ergodicity and quantum chaos”, with applications to medical imaging and robotics_.

_Another Unilag alumnus, Ayodele Dada, graduated with a perfect 5.0 GPA, an unprecedented feat in a Nigerian university_. _Victor Olalusi recently graduated with such stellar performance at the Russian Medical Research University, Moscow, and was feted the best graduate throughout the Russian Federation_. _Habiba Daggash, daughter of my friend Senator Sanusi Daggash, recently graduated with a starred first in Engineering at Oxford University._

_Emmanuel Ohuabunwa earned a GPA of 3.98 out of a possible 4.0 as the best overall graduate of the Ivy-League Johns Hopkins_ University. _Stewart Hendry, Johns Hopkins Professor of Neuroscience, described the young man as having “an intellect so rare that it touches on the unique…a personality that is once-in-a-life-time”_. _There is also young Yemi Adesokan, postdoctoral fellow of Harvard Medical School who patented procedures for tracking the spread of viral epidemics in developing countries_.

_Ufot Ekong recently solved a 50-year mathematical riddle at Tokai University in Japan and was voted the most outstanding graduate of the institution_. _He currently works as an engineer for Nissan, having pocketed two patents in his discipline_. _This is only the tip of the iceberg_. _If our system were not so inclement to talent we would be celebrating a bountiful harvest of geniuses in all the fields of human endeavour_. _This is why the correlates between our gene-pool and national development are so diametrically opposed._

_We are becoming a failed state. We punch miserably below our weight in the hierarchy of world economics and politics. None of our institutions come near the top 500 in the World Universities League Table. An estimated 50% of our people live in extreme poverty. Youth unemployment hovers around 45 percent (70% for the far-North). The poverty is heartbreaking. Our per capita GDP is less than $3,000 as compared to Singapore’s $55,252. We have the worst road carnage record in the world, with more than 20,000 lost to road accidents annually._

_We wasted over $18 billion on the power sector and our people still live in darkness_. _The state governments are virtually bankrupt_. _It is only by investing in science and in our young people can we forge a better future._ _Without science and innovation the African people will never overcome their millennial servitude._ _And the African Renaissance of our dream will become a mere phantasmagoria_. _We must create an ecosystem that enables science and innovation to flourish_. _And we must incentivise talent while building a merit-based society._

_In Brazil, a Nobel laureate is entitled by statute to the same pension rights as a former President._ _Society must adequately recognise and reward all men and women of excellence_. _Our government should keep a roster of all super-achievers of Nigerian origin and we should tap their brains for the building of our country._

16/07/2023

DAMPNESS
Dampness is the presence of unwanted water in the structure of a building, by the result of intrusion from outside or condensation from within the structure.

Dampness in building can be caused by

🔸 Heavy rain water that falls in the external wall of a building then percolates in.

🔸 From the top of the building wall: this is common in uncompleted buildings/decked building that is yet to be roofed. the rain water seeps in through the slab or the top of the wall if the rain water is not well drained and causes dampness.

🔸 Condensation: when warm humid air is cooled, condensation takes place, moisture is deposited on the walls and causes dampness.

🔸 Through a faulty conduit pipe in the building

🔸 Ingress of moisture from ground: ascension of liquid from the foundation can also cause dampness in the building; the solution to this will be discussed below.

*How to treat dampness caused by capillary action from the foundation on a building:*

1. Identify all the walls with the dampness issue

2. Make sure the walls are accessible from the two sides because you will need to break some parts of the wall and this breaking can be effectively managed if the two faces of the wall can be accessed.

3. Break the wall carefully and alternatively from at least below the tiles level up to 150mm height above the tiles alternatively, I mean breaking a part, skipping a part, etc. Let's assume the wall to be treated is 6m long then you can decide to break the first 1m (up to 150-200mm from below the tiles level), then leave the next 1m, break the next 1m, leave the next, etc. I hope you understand. it should be done this way because the wall may collapse if you break it all at once. so put in mind that you are spending about 24-48 hours to complete.

4. Mixing of concrete: mixing of concrete should only come after you have broken the wall. the mix ratio usually used for this process is 1:1.5:3, the coarse aggregate size must be 12mm or chippings and the fine aggregate must be a very good sharp sand, any other material other than these may not work properly. Your concrete is mixed with chemical, mostly used chemical in Nigeria is Dr. Fixit waterproofing chemicals (liquid), or any other waterproofing chemicals - make sure you read the technical data sheet of the product you want to use before using.

Make sure your concrete is mixed on a clean surface where it will be free from other foreign materials like clay or other dirt.

In other to get a very good mix with the chemical, it is better to mix the chemical with the water you want to mix with the concrete and mix thoroughly. And also it is very important that your concrete is not watery.

5. Make a formwork along the broken wall at either of the two sides (whichever is convenient) and start casting and compact it in thin layers with trowel and complete this process in all the broken parts of the wall. then leave it to cure or set for a whole day.

6. The next day, you will break the leftovers 1m that you left as support for the wall and repeat same process of yesterday.

Make sure the new casting is well bonded with the previous cast.

7. After completing that you are going to scrape the wall on both sides and plaster it with mortar and the same chemical (mix ratio for the mortar is 1:6 or 1:7 of cement and plastering sand) then range it.

8. it is advised to leave the wall for 5 days or a week before painting the wall because the chemical used may react with the chemical in wall.

after this, all finishing touches can begin...

16/07/2023

Reinforcement preparation and placement require pratical knowledge, careful planning and should not be approached as guesswork or a last-minute cramming session.

Typically, in most cases, the shorter span reinforcement is placed first, followed by the longer side. However, in the case of combined footing, the longer side is placed first, and the shorter side follows.

Currently, there are various structural design drawings circulating, created by individuals who may not have the expertise for analysis or design.

It is crucial to understand the proper techniques for reinforcement preparation and placement, as well as how to create a bar bending schedule table in accordance with code guidelines. Failing to grasp these concepts can have serious consequences.

Many structural drawings lack relevant details, requiring editing and improvement in presentation.

If your goal within the construction sector is to avoid being involved in a building project that may collapse, consider joining an online training course on Reinforcement Preparation and Placement.

WOli the builder offers such a pratical training for a fee of #5000, limited to only 20 participants.

Registration will close once the participant count reaches 20.

The training is organized for individuals who genuinely need the knowledge, but it has been opened up to allow more people to join.

To register, please make a payment to the following GTB account:
Account Number: 0019481965
Account Name: Adeboye Adeyinka

After making the payment, send the proof to my direct message (dm) to be added to the training WhatsApp group.

Delay is dangerous!This type of training may not be available again.

14/07/2023

Engineers, do you think it wise to leave rebars out in the open during a halt in construction? And do you think it will reduce the overall strength of concrete?