ingenuity

BUILDINGS TOO CLOSE TO THE BOUNDARY

2010-08-27T14:37:00.000-07:00

A local council passing a law that building should be
1.5 to 2 6m away from the boundary line is good but
this law really should not apply to developers in
cosmopolitan areas. I mean, the engineer has ways of
protecting even when buildings are exactly on the
boundary line. So this law is a result of those who
draft it who are not aware of the engineer's capability
and for not having consulted the engineer, they thus
try to assume the position of being the engineer.
Which is very terrible to the society. You who are of
another profession or layman should not tamper with
life that way or arrest development with skimpy laws.

Nathan Ddumba

FOUNDATIONS OF BUILDINGS.

2010-08-27T14:35:00.000-07:00

FOUNDATIONS OF BUILDINGS.
-------------------------
what do we do when soil investigations are done at the site?
What are we looking for?
And who demands these values?
It is the engineer to make sure your building is safe.
What is needed is
- the shear strength parameters of the soil
and
- the unit weight or density of the soil
These will be needed should an engineer want to determine
the safe bearing capacity of the soils underneath the
foundation to be of the building.

Then again, should the engineer want to know how
far deep you will have to excavate, the following
site investigations would be needed:
- depth of the excavation
- shear strength parameters
- the water table position.
With these, the engineer will tell you how deepest
down you can indeed excavate.
Chucks of soil normally fail but not necessarily the
whole shoil mass failing, so stand warned, such result
from cracks within the soils which are so so hard to determine
But know for sure, when there is a road or a building nearby,
expect unknown such failures and the engineer will not
ever have the slightest idea of where they will begin from
but can estimate, say 70% of the possibility.
Soil is the most unpredictable element around because
of repeated forces impacted upon it by man's activities,

Nathan, dec2009

KAMPALA'S BUILDING INFRASTRUCTURE.

2010-08-27T14:09:00.000-07:00

In light of the recent catastrophes since the begining of the new millenium, it's on a sad note to have had life lost due to the laxity in the building procedures. During the end of the last millenium, such catastrophes were so minimal and did not cause public alarm. Before, buildings were simply done and barely was anyone involved in putting up a big structure. All businesses seem to have existed in buildings built in the 1970s and before.

Best practices are always, or should be, set for all buildings and their are normally presented in form of technical specifications. In most cases they are standard. All major projects in Kampala should include along them technical documents. The selected contractor is also supposed to produce a construction procedure document indicating how they are to go about the project. Because there are laws existing hence they can work but failure to revise them over certain periods hence the problem. One major problem is when a law to include provision for parking set forth.

QUOTE:
[
The building professionals in Uganda have failed to impress upon us a set of best practices that are ideal for the soils, drainage in Uganda. It is an open secret that even the most elegant structures in the city have cracks: some major, others minor revealing compromised foundations.
]

THE DEVELOPER'S DRAMA THROUGHOUT HOME CONSTRUCTION.

2010-08-27T13:35:00.000-07:00

The developer, also called the-boss/client/owner, is ordinarily faced with two major monsters on a building project, namely, the foundation and the suspended slabs.

1. The foundation.
"Say, how in heavens, can over 75bags of cement get buried in the ground?"
Such has always been the developers's rants when building foundations for their residential houses. And when the ground floor is cast, after taking on another, say, 75bags, the developer is dried up after drying up the cement-store. Rests a bit for say a month or so until the developer garners enough power to continue with the...er...superstructure(construction above the ground floor).

2. The suspended slab
The word 'suspended slab' is an engineering term.
Ideally all those floors not supported directly by the ground are suspended, hence suspended slabs...such as the 1st, 2nd, 3rd floor e.t.c
And before their quotations are complete, you, the developer, are already yelling..."You're kidding, you expect me to give you 150bags of cement in just two days for this little first floor slab".
And not for long, you, the developer, are already looking for a less expensive builder(70% fake) who will conform to your desires, saying that, "hey boss, 70bags can also work, dont worry, I've done it before here and there for 5years "

...and the fracas is already on even before the quotation for the reinforcement bars has been done.

So we have to accept that these slabs are monster-eaters in that the whole lot is best done at once and not in stages. Meaning that you've got to splash the 15m-Ushs(8600USD) all at once for a slab, of say, 150m2 area in less than a week. That's when you feel for the owner...I mean it takes an ordinary middle-class citizen a year or so to earn this money..only for it to be spent in just two days as if...oh gosh!
Then in a bid to save on it, the owner starts getting stupid, thereby resorting to quack builders who are "quote" cheap. Thats why you'll rarely see an engineer or even an architect on a residential building.

The roofing.
Okay by the time the developer survives this far than anything is possible. Ideally the roof shouldnt be a big issue, that's if, you, the developer, wont be alarmed by the quantity of roofing timbers.

Finishes.
And the most annoying item on the building is the finishes. Finishing details are so many that sometimes the beauty is only seen when all these fine-details have been completed...ask the decoration expert. That's when you, the developer, keep on complaining, injecting more money but seeing nothing. Patience you need. You see, finishes on a development is like fine-tuning a musical instrument for the best sound. It might never end. Musicians can attest to this.

--> Nathan.(Apr2009 writing collection)
MSc.Structural Engineering(Tongji Univ. Shanghai, China)
BSc.Civil Engineering (Makerere Univ, Kampala, Uganda)
Member IABSE, UIPE, SEAINT
d-nathan@engineer.com

THE WELDING MACHINE FROM A PLACE CALLED 'KATWE'.

2010-08-27T13:30:00.000-07:00

THE WELDING MACHINE FROM A PLACE CALLED 'KATWE'.

And I visited this place called Katwe, and I was to buy a welding machine,locally made as it was cheap running between 400,000ushs to 500,000Ushs.

Prior to that we had bought one from big shop called 'Game' running at around 350,000Ushs. It turns out that the welding machine could not work on mass production of steel products like windows, doors and staircases. The 'Game'people were good,
as they allowed us to take back their product. And so, that's how we turned the
eye to Katwe.
Yeee!!!, support for the locally made stuff.

Now about that welding machine from Katwe!
It was a complete shame on me to see the barely uneducated having made something that works and me, with all the technical knowledge about the machine only knowing it in theory. This, I termed, the fine gap between theory and practice. It had nothing to do with the fact that I couldnt make the machine but the issue was 'why should I make it?' This question if looked at in more details would be the sole basis of why students should go higher institutions of learning..the university.

I was so eager to give this uneducated inventor/copycat more knowledge of what they are producing but it was so hard to change all those electrical engineering terms into the local language.
For example, how do you say 'electromagnetism' in the local language. Or rather when I said the word 'current', everyone got confused with 'current'events...nooo! I had meant electric Current'.

Now after recovering from the fact that a person with no prior knowledge, than
did I take a more detailed 'look' into the machine...oops! it turned out that
the machine was just about, say, just over 50% efficient.
Turns out everything about the machine was not as good as portrayed by the
aper. The aper had done some very good marketing of the product.

In layman's language, a 50% efficient machine simply wastes the remaining 50% of
your electricity consumption just like that. And the friendlier power guys will say, "your bill please!"

Ahh!...guess what comes next...
checkmate once again!!!
like the water-guys,
suffereth we do.

And what would your next move be...
...before you trick the electricity company...
...bypassing the meter...
...in a bit to save on the electricity...
...and specifically that extra 50% waste...?

It would be wise to get advise. For example, observations on this
Katwe-made welding machine showed that;

"1- the way the windings had been done was so exactly poor
2- the laminated plates had been poorly packed, air-gaps reduced efficiency
and likewise leading to more power losses through heat, sound, hysteresis and eddy currents plus all that other jargon. In otherwords, improving the mutual inductance between the two windings was key to a highly functioning welding machine.
And for this reason much power had been lost during the transfer from the primary to the secondary windings thus reducing the effectiveness of the device. This meant that it was not optimised to work as an electricity saving device.

Forsooth making high quality welding machines from Uganda is so possible and just as easy as it was with the vehicle made by the Makerere engineering guys. Later on that vehicular machine.

Now prior to that,
...these guys ignorantly informed me of how their local stuff works better than
imported items...which was partly true. Likewise they had told me of how better they are than the engineering graduates from Makerere...which was so out of context...oops I sorried them ignorant ones.

To clear the air, the engineers from the university can not be compared to those faulty inventions from the un-educated people. There is no comparison point, everyone has their downsides which are exactly 'orthogonal', the meeting point being 'non-productivity to the society'.

For long the Katwe people have been given accolades by investors and government
for being productive, while sharp, but correct, criticisms have been directed to universities.
In actual sense, almost all these products from the barely educated people function at less than that acceptable efficiency, while on the other side, universities have produced educated people who have not been productive but
good grade-getters.
so,
Who tried?
Who didnt try?
who benefited?

You see...
according to the PRESENT SITUATION...
it's better to have a less-efficient product than a degree-person walking with latent knowledge that can not be output
into a real product. In fact I was able to use the low-efficient welding machine to fabricate all the 40windows and 5big doors. The electricity bill was huge though.
Nonetheless,this proves the fact that....

"knowlegde not shared-is-indeed not knowledge".

--> Nathan (Apr2009 writing collection)

The goal of every engineer is to retire
without getting blamed for a major catastrophe!
...Dilbert

DONE
--> Nathaniel.D.M
on Variety engineering.
Civil/Structural engineer!
CG- 3DsMax2009 Animation Professional!
Amateur Astrophysicist/Astronomist!

INVENTIONS FROM BARELY UNEDUCATED PEOPLE

2010-08-27T13:24:00.000-07:00

INVENTIONS FROM BARELY UNEDUCATED PEOPLE

The only thing that unites the educated and uneductated is innovation.
Great debate is whether innovative abilities are studied or just natural.
In the most simplified and dignified manner, these abilities develop
naturally through proper ways of livings. Meaning that everyone has
the ability to be innovative. And this ability grows depending on your
greater need to serve and to love. Call it what you'd but it is
normally called Christ-love.

Great innovations come from an inventor with a greater purpose.
Many inventors are not really inventors but mere copycats who
only selfishly seek to earn a living.

In Uganda, the major talking point are our people at a place called Katwe,
where many little things have been made by barely uneducated
ones in the field.
And these things have been called innovations. In actual sense they
are not innovations, it's merely being a copycat...just as the Asians
have copied all the western technology.

In the Asian's case, however, their copying sometimes surpasses the original.
And in most cases they get a direct helping hand from the educated through governmental support programmes where the overall result is affordability
to all whereas the Katwe people have been mainly for their stomachs hence
no advancement.
While in the case of Europe and America, inventions from the uneducated
take a slightly different twist. Most of these are not just copycats but new or
modifications to the established. And the western law has protected their
inventions through patenting. Great inventors like Faraday who
never passed through formal education were protected by such
intellectural property laws.
This gives a pretty good idea of how great-governments arise.
Great governments do not arise by merely making strong money policies but
by also providing various conduits for technology distribution/transfer to all.
Sometime in the future, patenting will also be strong enough in your country.

--> Nathan's collections of Apr.2009
MSc.Structural Engineering(Tongji Univ. Shanghai, China)
BSc.Civil Engineering (Makerere Univ, Kampala, Uganda)
Member IABSE, UIPE, SEAINT
d-nathan@engineer.com

FLUSHING TOILETS

2010-08-27T13:16:00.000-07:00

FLUSHING TOILETS.
Based on (Research + professional touch):

Flush toilets, also called water closets (or WC's)...have two
major items; the bowl and the water reservior,
both ceramic-made representing the engineer's touch of genius,
all for your comfort.

Two types I've encountered so far, one is the squat-type
and the other, the seat-type as comfortable as a sofa.

And it would be so strange for someone to sit on a squat-toilet,
I mean, with the bums directly in contact,
just as it's exactly sickening to find someone having squatted on
your toilet seat, with the feet on the edges of the bowl...not for
anything but a mere taboo or norm
found in some traditions throughout the world. Sometimes you
wonder how cultures worlds apart share the same taboo...!!!

Now look!, after doing the important work, lo and behold!,
the toilet flushing system fails to flush the contents out of
the bowl, yes just imagine! you needing to frustratingly flush twice
everytime you visit.
And, well, in some strenuos occassions, you may want to get water in the
bucket, raise it high enough and pour it into the bowl with enough pressure
to finally...wheeew!!!..flushout the contents from the toilet bowl.

And how much water have you used?
And yet you MUST, have to, visit the toilet again, tomorrow, everyday,
many times, every month of the year!! Boy or girl, dont you love visiting
the toilet more than your loved ones!?! or are you made to visit under
duress by your own body system
or is it that you have taken on the responsibility of being the health-
implementor of your own body system.
Whichever way, you'd be just about the best customer for the water-bill guys
full of smiles of "hey-buddy, your existance is our topmost priority" ...your bill please!!!.

huhh!!!! that's called a checkmate my friend!
suffer ye to be victim of imperfect designs or wrong choices

What would your next move be?
To blame the mechanical engineer?
the maker of the flushing toilet?
or to go to the market to buy a brand new all-expensive flush-toilet?

Wouldnt that be a little extra torture resulting
from ignorance of the things that are?

And why go through all this torture?
Simply because you had that famous heavy meal
producing heavier stool?
Say, did you eat the African food?, I mean, have you noted that stool from
the African tends to be much heavier than that from the Asian or Western!?!

"Have you noted", adds on the engineer, "that even the flushing system
technology is much more reliant upon the heaviness of the stool passed
out by the user...er...food-eater, you! ?"

What we are trying to say is....

One system spirals water in the bowl whereas the other
pressure-powers the water down, i.e., it pushes it down.
Within these two are the many sub-categories depending on the
manufacturer.
It's highly likely that the one in your house is of the spiral type.

Ideally you'd also like your toilet to save on the water while
operating at maximum performance, typical of the push-down type.
And shhh.... it shouldnt make
so much noise that late at night and more-over every-night!...typical of
the spiral type.
Latest technology in toilets are now incorporating pressure
assisted flushing of water such that you'll only hear that
quick 'whoosh!' while the contents are swooped out nicely.
Kohler toilet manufacturers call this Pressure-lite
Toilets sold at...ouh!!!...ooops forgot the pricing-issues!

--> Nathan.
MSc.Structural Engineering(Tongji Univ. Shanghai, China)
BSc.Civil Engineering (Makerere Univ, Kampala, Uganda)
Member IABSE, UIPE, SEAINT
d-nathan@engineer.com

SLOPES AND RETAINING WALLS.

2010-07-21T18:40:00.000-07:00

Pictures....grrrhhh!, wish the copy and paste was possible....

PS/the only reason we're talking about this is because landslides can cause loss of life and damage to property of the human.
And when they go off, they are like huge unstoppable monsters that dont give precise warning signs of their arrival.
However, when you see animals and birds darting off days earlier, the warning signs are good enough.

Bringing you up to speed!
First, see how devastating a land slide can be.
http://sorisomail.com/email/42722/ja-viram-desmoronar-uma-montanha.html

Sometimes it can be so obvious, Kampala city surburb, Uganda (the author calling it 'catastrophe in waiting')
http://www.monitor.co.ug/News/National/-/688334/896256/-/view/printVersion/-/xfo1yv/-/index.html

Also this one.
land slide manner

And this one below actually caused serious loss of precious life in Bududa, Uganda. Bududa(March 2010)
http://www.nation.co.ke/News/africa/-/1066/871740/-/122ljwsz/-/index.html
Residents of Bududa look at what remained after the landslide that left 80 dead and 100 missing.

Now you've got the picture of what we are talking about.

The simplified concept of a land slide
A land slide is when the soil along and near the slope fails to sustain its own weight and the weight of objects(trees, vegetation, houses, vehicles) above it.
These weights bring about stresses in the soil. The concept is simple, when these stresses exceed the soil's cohesive ability then the soils break up along made up slope lines causing a land slide. The soil's cohesive ability is in simple terms its strength or its stability.
These slope lines are called slip planes.
In such a case, the slope is said to be unstable....an unstable slope.
Do not ask the engineer to precisely predict slip planes, soils can have many inherent little fracture planes.
The most unpredictable engineering materials is soil.

clay landslide morphology land slide effigy

Categorising slopes
We do have built-slopes and natural slopes.
Built slopes are normally found around homes, business premises and factories.
The figure below is a styled up built-slope good for a home/business area.

Built-slopes are what we commonly we refer to as retaining walls.

Natural slopes are those around villages, country homes and roads, schools factories but also on hills or mountainous areas.

Image credit: http://farm1.static.flickr.com/3/3295992_af658c0623_o.jpg http://www.leo.lehigh.edu/projects/seismic/pictures/6.jpg land slide mannerism

land slide form

Moving around Kampala-Uganda, the potential for land slides is just way to much. And the most areas I have seen are in residential zones for those putting up homes on hills. The situation is almost unlike other cities in other countries. Kampala is hilly throughout, that's one of its unique features. Some of us have on various occasions been asked to propose solutions for these steep slopes and the methods we've proposed have been called expensive as they get to a tune of about 15% of the construction of a home. In money terms, that's about 10m Ushs(5,000$) for ordinary homes(three bedroomed). And this value can go up to over 100m Ushs (50,000$) for bigger homes and organisations.

Likewise unprotected deep excavations for storied buildings within Kampala are still going on despite the recent soil collapses killing people. And the Ugandan engineering community (UIPE) has already talked about it but it has not sunk in well into the mainstream life.
This is where you, the information distributors, come in. And the way forward is simple. Big-styled buildings needing deep excavations will require that the contractors present construction methods to the consultant and then to the council including details designs/drawings of how to protect/brace these steep slopes arising from deep excavations...but that's for another day. Key issue is, this is a man-made slope that can easily fail causing life-loss to construction workers. And by the way, similarly around the world...however, the HSE(health, safety, environment) institutions in some countries, say, scotland, have some strength...case in point, a contractor last month was persecuted for failing to support a 1.8m excavation within the given deadline, click the link...link 1, link 2

piles

Cause of unstability in existing or made slopes
Three main causes that have to be curbed are
1. The human
2. Water,
3 Earthquakes/tremors
The biggest cause of instability for existing slopes is water. All water has to be directed.
Water has a tripple effect on soils.
1. It reduces the soil's cohesive strength
2. It adds its own weight to the soil.
3. It adds pore-water pressure within the soil.
Earthquakes enhance slip planes or create new ones and likewise reduce soil stability through direct tug&pull.
Looking from the engineering viewpoint, the human is also a menace when it makes deep excavations and many judgmental errors. The human has to be curbed through awareness because unlike the other two, it has a mind and can WILL...but if stubborn, then the law is needed when the problem is community-affecting or letting it be a victim of its own fate if it(this human) ridicules all your efforts to help it.

Most of land slides occur during unending rainy seasons and strongly increased by tremors and built-up environments, such as paved yards, roads and most especially roof tops. A strong down pour is not as harmful but those unending soft-pouring rains are.
Whenever it rains, the cohesive ability in soils is reduced. The more it rains the more the reduction in cohesion.
This is because water infiltrates within the soils through the soil pores making it waterlogged.
In otherwords, the more waterlogged the soils, the more its weakness in strength.
If your house is situated near a slope, never give chance for the slope to ever become waterlogged by choice.
This water has to be drained out as fast as possible.
That's why most people put up hidden drains or weep holes(see figure below) along built slopes or retaining walls (see figure below).
http://www.burkesbackyard.com.au/img/archive/1814/retainingwall_22.gif
Built slopes without weep-holes WILL fail.
When you move around, you will see constructors including weep holes on retaining structures.
Slopes rarely fail on their own weight, and most especially for soils in Uganda.

Are people aware?
I honestly do not know if you look at the picture below.

PHOTO BY ISMAIL KEZAALA. from www.monitor.co.ug.

Taming Land slides
So this is where the engineer's assessment, design and mode of construction comes in.
The engineer does not work alone...for community projects and beyond, a full complete team is needed. Briefly outlined below
1. Site Investigation(investors, construction consultants, economists, politicians, enviromentalists, geologists,... list goes on as needed)
Construction consultants here include architects, engineers, hydrologist and surveyors
2. Benefit (investors, economists, politicians, enviromentalists,.. list goes on as needed)
3. Planners(consultants...)
4. Soil properties (geologist)
5. Models & Simulations(consultants)
6. Hazard rating and mapping (consultants, council)
7. Risk and cost analysis (consultants, economist)
8. Finalised engineering design&details.(consultants)
9. Construction.(consultants, builder)

When the soils are highly cohesive, you do little on steep slopes, less expensive.
When the soils are less cohesive, you're advised to make the slopes less steep or built-up properly.

Key factors.
1. Stay away from slopes.
2. But if you cant contain (1), then stay at a distance from the slope equal to its height.
3. Do not reside at the foot of a slope, be above it and at a distance away from the slope equivalent to its depth.
4. If you cant contain (3) & (1), and are that upclose to the slope, build an engineered retaining wall and for God's sake provide drainage options for stormwater esp. that off your roof.
You can turn a nuisance steep slope into an architecturally looking beautiful retaining walls around your homes.
All you have to do is ask the architect for beauty and the engineer for structural feasibility and other stakeholders for related feasibility(s).

That second pic is a honey combed wall. Common if you walk around.

Designs exist, freely given if needed.

5. Also do not forget that for big slopes, needed are anchor rods or dowels (figure below) + chainlink(or strong wire mesh or geosynthetics, see figure below) along the slope + lime-stabilised soils + and proper drainage of stormwater channels.
rock slope stabilization Vegetated steep slope application photo
http://www.terrafixgeo.com/uploads/60_SierraScape_7M.jpg

6. With inclusion of some concepts in item 5, you can beautify your retaining wall with a serious stone facading.
Retaining walls and vegetated steep slopes - system drawings

Retaining wall application photo

6. Soil stabilisation(see below) also somehow tames land slides as seen in the deep hills of Kigezi, Uganda.

okay.

Nathaniel. Ddumba
MSc. Str.Eng, BSc.Civ.Eng.
M'IABSE, M'UIPE, M'SEAINT.

2010-03-06T17:39:00.000-08:00

written in a hurry
[unedited]:
| n'joy |

WHEN ENGINEER IS ACCUSED
~~~~~~~~~~~~~~~~~~~~~~~~
Here is one engineer last year in Uk who got into a contract to supervise a certain job and got into serious trouble. It was the contractor who had put the engineer in the mess and the client latched onto the engineer to pay for the errors because he was not on site when the contractor was making the errors. Ofcourse, the engineer could win the court case but the time and money to do all this was getting on his nerves plus the fact that he had other work on his plate that he wished not to be affected. Such was his weakness and he transferred it to the institution of structural engineers for solace. As I write now, he has probably done a few calculations and has probably accepted to take in the error, so that his works are not disturbed. Point is, how can the Institute of Structural Engineers in UK protect such and do they have a provision for such?

WHEN THE CLIENT ASKS FOR TOO MUCH!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
He asked, how much can such a roof truss cost?
The foreman said, about 75,000/-.
Ah!?, and 10trusses would cost 750,000/=?
No, said the foreman, but 300,000shs.
And that confused the client who wanted to know the exact price so that he doesnt
feel cheated by the foreman
The client wasnt convinced for he thought that in that case if
300,000/- is for 10trusses then for a single truss, that is 300,000/10 = 30,000.
"No sir", said the foreman, "it has to be atleast 70,000/=."
"You think I didnt study math?", said the furious client.
And the foreman humbly replied: sir I know you are one of these great
mathematicians but that is academics and this is our turf, in a real situation,
sir, making a single truss means a waste of my day's effort if you are to count
theoretically like that. Realistically, the whole day would be wasted.
Thus asking me to make one truss in a day is more expensive than making 10trusses.
And the client went to look for another foreman.
I only got to know when the client was narrating to me the whole ordeal
and I wondered how I would break the news to him, that you(the client) were the
wrong one instead.
This was one of the many times when clients prefer to handle the technicians
on their own. This is very problematic everywhere in the world you'd go to.
Nathaniel
feb'10

WHEN THE LABOUR PRICES GO UP
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Client: I want to pay you on a daily basis
Foreman: ok.
Client(C): so how much
Foreman(F): 95,000shs
C: (he is not amused):
F (notices it and explains): In a day, I would need two skilled ones and two porters
to do the building work.
Meaning that I get 50,000/=, every skilled man gets 20000/= and a porter gets 7500/=.
And the supervising engineer gets off 2000/= from my salary for sacred trust issues.

C: But last two year, I read that a foreman gets 35000, skilled=12000, porter=5000. You cheating?
Why the increase?
F: Because you have increased price of bread at your supermarket.
C: (not amused)
F: actually more sir, your transportation system was increased by 500/=, sugar increased by 300/=, food by 300/=, fruits by 400/=, you, the chairman of the board for our school increased the fees by 100,000/=.
In otherwords, sir, you've increased all the basic necessities, and that makes me unable to sustain my family unless when the salary increases by an extra dinaro!
C: ashamed, he now knew that "what goes around indeed comes around!"

He was wrong in thinking that those stinging decisions only affect the others minus him.
Little did he know that every decision he would make would eventually get back to him
through the interrelated network of activities that joins all people within the community.

He now embarked onto breaking this interrelated activities where the workers would be made to pay for more without the workers having sufficient reasons to ask for a wages increase! he dreamt on.

WHEN THE LABOURERS DID THE TRICK ON THE CLIENT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
As the client figured out ways of making more money, he thought of a way of breaking the inter-related activities so that the construction worker pays more for the necessities without the workers asking for more during the construction of his new supermarkets.
Huh! he continued dreaming on. The workers likewise were figuring out of making more money from the client.
They had kind of made it easier on them.
They had persuaded the client to pay them on a daily basis.
Meaning that a wall that would be constructed in a single day would take 1.5days.
It is that easy, even when the client is on site. The workers would be so busy yet
not finishing the works in the required time. This extra trick by the workers was
due to the fact that the client had refused to increase their daily package meaning that
- the foreman would get 35000/-
- the skilled worker 13000/-
- the porter 6000/-
- the supervising engineer taken out of the picture.
The client was particularly so confused as to why the supervising engineer(also called architect) would visit the site anyway and more to that get double the money, part from the foreman and part from the client himself.

THE CLIENT'S CONFUSION OF THE SUPERVISING ENGINEER'S ROLE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Thus the client did the simple math.
Ideally, the supervisor would visit the site on mondays, wednesdays and saturday morning and would get
65,000/- from the client plus the sacred trust fee from the foreman.

So reasoned the client, sitting on his porch facing the lake waters. Pondered him that if the supervising engineer is taken out of the picture, him alone would save 65,000shs x3day=195000shs per week.

And this saved money would be used to buy an extra 1000bricks on site that would be able to build an extra 6m long wall on his supermarket.
Behold, the client had done his math up to this point and saw it was good. In order to fill the vacuum, he
did raised the level of the foreman to be a site engineer and according to him, all was good.

Problem was, he was breaking the sacred trust between the supervisor and the foreman who are the only ones
who can fully discuss technical issues in between them. Likewise, the lesser workers had seen it as an opportunity to pounce on any opportunity to trick the socalled witty client and the technician on material usage. The client has not any idea that these workers have a kind of psychology that sometimes surpasses a university-trained psychologist. These workers could would infiltrate the client's mind with such petty issues as to how they have built similar houses even without the need for those socalled professionals who call themselves architect, engineer, surveyor...etc! And the client had bought it just like so many clients do these days.
And thus the building started developing cracks. And the client recalled the supervisor telling him that it was your work to confirm that the drawings are correct. "THAT'S WHY I PAID YOU FOR THE DESIGN", shouted the Client.

WHEN LOCAL WORKERS'S PSYCHOLOGY RUIN THE CONSTRUCTION INDUSTRY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Who, for heavens sake would have believed that these people use their mind in the most cunning of ways?
Which later gets discovered by the general public?

WHEN THE LAZY ENGINEER GOES SELFISH
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The client reasoned out the engineer by telling a story of a friend who suffered at the selfishness of the engineer. He thus concluded:
It wont take you long to notice that so many engineers step out of the loop of their fellow engineers trying to look for a little extra more buck and by so doing steping out of the code of ethics boundaries that every engineer has to follow. It wont take you long to see that such engineers have stagnated to the extent that what used to apply some years back is already taken out of the picture.
And the client had been warned.
The client had been told that when chosing an engineer, seek to know their activity roles with other fellow professionals, professional societies, for such constant activity roles makes two or more people grow within the profession.
The client had to listen.

THE MAKING OF A QUACK ENGINEER
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Come on guy, what have you been doing in the village?
I've been building huts and i have seen that they do not fall.
I have a lot of experience big enough to build a skycraper.
And the client was savvy not for anything but he saw this one
would be cheaper.

3DS MAX 2009 - ALCOBOND-GLASS BUILDING

2009-06-16T06:12:00.000-07:00

Touch of ingenuity....done in 3ds Max(only the protruding part of the shouting building...the creamish aluminium last floors) and inserted in a realistic photo using photoshop. More later.

CHURCH ROOF STEEL STRUCTURE

2008-11-10T04:01:00.000-08:00

More pictures, less words.
Below, spatial modelling using AutoCAD.

AutoCAD 2006 in 3D. I used its 3D function to analyse a steel roof truss. It gets much easier to model using AutoCAD for linear spatial structures and transferring them to you analysis program of your choice.

Remember: That modeling needs not to be near perfect, but every inch perfect…that is if it is to be transferred to an analysis software. Perfectness is when all lines intersect exactly on the joints, not near intersection but exact intersection. If there’s a difference of less than a centimeter, the analysis software will call them two un-joined joints.

Then analysis using AVWin98. Figure below shows, truss system doing the calculation of moments after doing the complex modelling stance done in AutoCAD and transfering it to AVwin98 threw the import dxf file method, and defining each member(tricky one) together with the loads they carry(more tricky)

Thus some serious work was done here.
The elements had been defined and loads put in. There is a new version to this software, simply do not remember the name....probably something close to AVANSE or something. Will find out later.

The results to be presented at a future date. Most likely to forget.

NATHAN.
Kampala Uganda, East Africa
BSc. Civil Engineering (Makerere, Kampala)
MSc. Structural Engineering (Tongji, Shanghai)
Member_IABSE (International Association of Bridge and Structural Engineers)
Member_UIPE (Uganda Institution of Professional Engineers)
Also on the SEAINT list (Structural Engineers Association International_US)
Also on the CR4 list (Conference Room 4)

REINFORCEMENT BARS: TO BEND OR NOT TO BEND

2008-11-10T03:42:00.000-08:00

We have to know that when bending occurs, the steel bar is strained within a certain section. The strain increases along the cross-section of the bar with the least strain closer to the direction
of bend and the maximum strain away from the direction of bend.

Some people have seen these strains to be about 0.02.

In bar bending schedules (BBS), this strain item is dealt with when dealing with bend. The bending in this case is for anchorage. In whichever case, I intuit, the strength in the area of bending may be reduced but not enough to be weaker than the bond between the concrete and steel bar surface. That may be the reason why bending in codes continue to be.

Caption from a dissertation chapter 4 "CONCRETE-STEEL BOND MODEL”

Well, in Uganda we mostly use twisted bars.
But there is another scenario at play: working with bars already embedded in concrete. What does this mean to the concrete already cast,
- will concrete cracks/spills be induced when the bars protruding out of the concrete are bent close to the concrete
- will concrete strength be affected by heat when heat, say heat from welding, onto the bars extends to the concrete sections nearby.
Does any of these loopholes affect the composite strength? It is indeed a real question to ponder on when considering that during design, so many factors of safeties are included in various stages of the calculations which I intuit should be enough to take care of these ‘minor’ holdbacks. But I still reserve the comment to certain concrete sections where there is a high degree of shear stress such areas as where concrete staircases begin/end, where concrete domes shoot off from a ring beam. But for areas such as starter bars, this really should be safe.

What do the others say:
One article (ref 1) states: that cold bending and straightening of rebar embedded in concrete does not weaken the bars if they are not bent through an angle greater than 90 degrees and the procedure is used only once. This was after conducting 56 tensile or stress tests, on rebar manufactured in New Zealand.

In ACI 318-77: 7.3.1: All reinforcement shall be bent cold, unless otherwise permitted by the Engineer.
In ACI 318-77 7.3.2 : Reinforcement partially embedded in concrete shall not be field bent, except as shown on the design drawing or permitted by the Engineer.
In ACI 318R-77, 7.3.2 "...The inspecting engineer must determine whether the bars can be bent cold without damage, or if heating is necessary. If heating is required it must be controlled to avoid splitting of the concrete or damage to the bars."

In an ACI Journal (ref 3): it recommends pre-heating rebar before gently and gradually bending it.
In a concrete international journal (ref 4): it was not necessary to use heat before bending the rebar. However, they only tested #8 (1" diameter) bars.

In a rebuttal to Ref 3 to Lalik and Cusick, again in a concrete international journal (ref 5): that it was hazardous to restraighten cold rebar.

Based on these and other studies, the Concrete Reinforcing Steel Institute concluded that: reworking bars entails some risk; #8 or smaller bars can be successfully field bent/straightened at temperatures above 32° F; rebars #9, #10 and #11 have a better chance of being successfully bent/straightened when preheated to 1400° or 1500° F and carefully manipulated; these conclusions do not apply to #14 or larger rebar.

After reviewing the three articles summarized here, as well as other studies, Monolithic's President David B. South said, "All of these studies show that care must be taken, but the smaller rebar sizes #3, #4, #5 and #6 usually can be bent cold as needed. However, care should be taken to make smooth bends, not kinks. Generally, the rebar is sufficiently forgiving -- especially #3 and #4. Larger bars (larger than #6) take special handling and may require heating."
So well, that does it.

REFERENCES:
Ref.[1]:If you want to know more, check the article "How Harmful is Cold Bending/Straightening of Reinforcing Bars?", by Authors José I. Restrepo, Senior Lecturer in Civil Engineering at the University of Canterbury, New Zealand and Member of the ACI (American Concrete Institute); Francisco J. Crisafulli, Senior Lecturer at the National University of Cuyo, Mendoza, Argentina and ACI Member; Robert Park, Professor of Civil Engineering, Deputy Vice Chancellor at the University of Canterbury, New Zealand and ACI Honorary Member.
Ref.[2]: ACI-318 is American Concrete Institute’s Building Code Requirements for Reinforced Concrete Structures
Ref.[3]: William C. Black in "Field Corrections to Partially Embedded Reinforcing Bars," ACI Journal, October 1973, pages 690-691
Ref.[4]: J.R. Lalik and R. L. Cusick in "Cold Straightening of Partially Embedded Reinforcing Bars," Concrete International, July 1979, pages 26-30
Ref [5]: L. A. Erasmus in "Cold Straightening of Partially Embedded Reinforcing Bars--A Different View," Concrete International, June 1981, pages 47-52.

INTUITIVE ABILITIES IN CONSTRUCTION

2008-08-06T17:08:00.000-07:00

And while discussing with the foreman, it had been seen that there was a general lackof insight in doing finishes. It had been sited that most of the finishes done by this foreman was good but then he would spoil the work done in a particular sectionwith works unfinished in other sections. He knew it, I knew it. So then, it was notnecessary to tell the foreman what to do! All he could have done was to figure outways of protecting the earlier finished works from getting spoilt. Likewise the column pedestals had not been done at the same level by the previousforeman. The current foreman was to do a good finish on the pedestals taking intoaccount the levels but he did not do it. And so he had taken it for granted. Afterdoing the finishes did he realise that all the pedestals were not level. Then did I come in to tell him why he had not seen the problem, then I had to go through asmall lecture to teach him about intuitive abilities. I feel it's much my responsibility to teach these guys and not to simply assume thatthey know.Hey do you get the picture?

Nathan.

AVWIN98 & SAP SOFTWARE COMPARISONS

2008-08-06T16:49:00.000-07:00

Quick answers took me to trying out a few design software we normally use in civil/structural engineering. Not that I can not use my head to do the designs but because the computer does it faster without losing accuracy if well commanded. So here I was trying to pick out the best software to use in my daily earning business. On the table was SAP2000 and AVwin98. Unfortunately, my STAAD Pro is expired and my other design software are just demos.
In the calibration, I tried out a simple beam of 300mm x 550mm to be reinforced in bending to support its own weight together with other dead loads of 40kN/m and a live load of 12kN/m. Concrete to be of class 30N/mm2 and Steel of 460N/mm2.
So, three options were tried out; (1) hand calculations, (ii) sap2000 nonlinear (iii) AVWin98
Aaand here we go:

Hand Calculations in steps:
Get ultimate design load basing on BS8110 = 75.2kN/m
Get ultimate design moment = 338kNm
Using formular such as K=M/bd2fcu and As=M/0.95fyz, the area of reinforcement = 1696mm2.

SAP2000 Nonlinear in steps:
Draw the frame or File->New model from template
Go to Define->Material and choose Concrete, then ensure correct properties are filled in.
Define->Frame sections
Select Member and go to Assign->Frame Static Load-> Point and Uniform
Go to Analyse->Set Options
Go to Options->Preferences and chose concrete tab.
Press F5 to run analysis
Press Ctrl+F5 to display the area of the reinforcement on screen. The value I got was 2324mm2

AVWin98 in steps:
Using on-screen menu,
Click Nodes tab and input structure node coordinates
Click Beams tab and join the nodes.
Click Nodes tab, then its 2nd button and select the nodes to have restraints
Click Beams tab and describe the beam
On beams tab, 2nd button to choose section properties
On beams tab 3rd button to chose which material properties, select Aconc
On beams tab, 8th button to input dead and live loads, then combination load, i.e 1.4dl+1.6ll for BS8110.
To analyse structure, click Calculation menu -> Analyse Structure.
Below were the results.
Moment = 338.23kNm
Click Print Menu->Reinforced Concrete Design, which gives Rebar area = 1770mm2 as shown below:

AVwin 98
------------------------------------------------------------------------------
AVWIN REINFORCED CONCRETE ELEMENTS DESIGN
Constructors format
------------------------------------------------------------------------------
******************************************************************************
Notes
------------------------------------------------------------------------------
Only graphically selected elements are printed
Deflection should be checked by user
V3, M22 and Axial actions are ignored in beam design
Reinforcement ratio producing balancing condition is ignored in columns.
Shear and torsion is ignored in column design
Rectangular diagram of concrete is used for beam and column design
Only rectangular beams are printed
Only rectangular columns are printed
Two axis bending moment in columns is solved amplifying larger bending moment
Recommendable only for rectangular columns with symmetric reinforcement
"Type": U= open stirrup []= closed stirrup >[]<= reinforcement in compression "Left" is J node of beam. "Right" is K node of beam "IP left" (inflection point) is the distance from J node to inflection point "IP right" (inflection point) is the distance from K node to inflection point Stirrups separation is given for ranges: 0%-25%, 25%-75%, and 75%-100% of beam length M min/max are maximum and minimum bending moments found for this beam "Skin" es required reinforcement to resist torsion. Half the area should lie at each face Columns are verified at 5 stations: 2 end stations and 3 middle stations Slendernes is ignored in the design of columns. Analyze with P-Delta to account for it. Design code: ACI-318 DESIGN STATUS ****************************************************************************** DESIGN LOADS.- LOAD 1 : c1=1.4dl+1.6LL ============================================================================================ B E A M S ============================================================================================ BEAM A.left A.cent A.right I.P.lef I.P.rig SKIN STIRRUP SEP. [cm] Mmin/max V[KN] Long Num [cm2] [cm2] [cm2] [M] [M] [cm2] LEFT CENT. RIGHT TYPE [KN*M] T[KN*M] [M] 1 ---------------------------------------------------------------------------------------------------------- RcBeamR 30x55x3.5 TOP: 0.0 0.0 0.0 0.0 0.0 0.0 6mm: 10.8 24.7 10.8 U 338.4 225.6 6 BOT: 0.0 17.7 0.0 0.0 0.0 8mm: 19.3 25.8 19.3 U 0.0 0.0 ============================================================================================ C O L U M N S ============================================================================================ COL Faxial M33 M22 Load A.calc A.min A.max Length TIE SEPARATION[cm] B x H Reduction Numb.[KN] [KN*M] [KN*M] id [cm2] [cm2] [cm2] [M] 6mm 8mm [cm] of inertia ============================================================================================

So well in brief the results were as follows:
6m simple beam design, 300mmX550mm,

fcu=30N/mm2, fy=460N/mm2

dl=40kN/m, ll=12kN/m
Code used
Moments, kNm
Below: Area of reinforcement, mm2
Hand Calculations [BS8110 ; 338 kNm ; 1696mm2]

SAP2000 Nonlinear [BS8110 ; 362.9 kNm ; 2324mm2]

AVWin98 [ACI-38 ; 338.23 kNm ;1770mm2]

Conclusion: SAP2000 Nonlinear results were off by 27%(less accurate), AVWin98 was off by 4%(more accurate)
But then again, it would not cause the structure to fail because the factor of safety is actually much higher but less economical
Which would be the only reason why the Software designers would have to be more exact.
Next, lets wait and see what the SAP software designers say of this. They can be contacted at http://www.csiberkeley.com/ / info@csi....

Nathan.

MORE UPDATES

2008-06-14T11:08:00.000-07:00

update 1

2008-06-13T04:22:00.000-07:00

CASTING THE GROUND SLAB [being edited]

2008-05-22T06:58:00.000-07:00

So how is it done?

Materials: You need a well compacted base, hardcore, cement, aggregates and lake sand together with Mesh reinforcement popularly called BRC.

Mixing: You need cement, lake sand and aggregates.

Application: [coming soon]

Casting the ground slab. And everything now seems to be on course. The speed is cool...okay slow to the others but reasonable basing on the circumstances(no storage space yet)...hence whatever we bought had to be used up that very day.

Today we got the maxspans for the slab over the gulley. I changed the design a bit and now it is possible to use 5"maxspans and not 7"maxspans as long as that place will forever be used for toilet, bathroom, washroom, e.t.c

Today's work involved;

-timber shuttering for slab over the gulley,

- cutting, bending and fixing the bars

- putting in place the maxspans,

- adding on BRC.

I am out of money. Only remaining with 1m for the y25 bars.

More updates later on first floor works. Need to prepare for timber posts, more timber, more reinforcement, maxspans. This floor is going to be lightening speedy.

The building will be the best!

ciao!

Nathan.

INGENUITY, PART 1: [STRAP FOOTINGS]

2008-05-17T22:01:00.000-07:00

INGENUITY, PART 1: [STRAP FOOTINGS]

Ingenuity was called into question when I faced a challenging task that I usually dont meet.The column to be built was too close to the boundary. Ofcourse my worry was its foundation which was to project into the foundation of boundary wall. I instructed the contractor to do that but later we found out that the boundary wall would fail and believe me, I was not interested in extra costs or neighbour interference. I later found out that the contractor had gone a step ahead to preserve the dimensions of the footing by re-positioning it so that it just ends at boundary wall footing. But he had not changed the column position and I could not have allowed it anyway because of it was locked in grid with other columns. And so that column was now closer to the footing edge and no longer in its middle.
I had not faced such a situation before. I had to delve into first-time principles. Creative engineers have used intuition when faced with new challenges, I thus followed suit:
- One was to internalise the problem
- Two was to internalise the solution.
- Three was to work out the calculations
- Four was to specify the materials to the contractor.

INTERNALISING THE PROBLEM: [MOVIE-1]
In my mind's vision, I saw a load path from the column and into the footing, creating an eccentric effect that led to overturning gestures thus creating weak points. It was like a movie playing in my mind. I had to concentrate my thought energies to keep the movie on. Next, I played and replayed movie clips in the internal vision taking into considerationthe nature of the surroundings close to column and its footing. In the replays, I saw two possible scenarios:

1. a hinge was created at the column-footing intersection and a crack in the floor next to the column ensued as a result. I saw why this had happened.
and/or
2. hogging moments created in the footing next to the column which would come first before any possible failure at the column-footing intersection.

This internalisation took about a minute. I was quite for that period while the contractor was there wondering what I am up to.
And so the weak points had been located. Solutions had to come in next.

INTERNALISING THE SOLUTION: [MOVIE -2]
In my mind's vision, I dared not view the load paths for all the 16 columns. It would get complex and the movie would get distorted. I concentrated on two columns. I thought of a base beam(or reinforced strip footing) which connected the eccentric column to the other column and made it to sit on top of the footings.

Now I replayed movie-1 in my previous internalisation. This time I saw the introduced beam at work, seriously reducing on the overturning effect. The more I made the beam rigid, the more I saw the residue load from the eccentric effect being transfered into the next column footing.

The problem had been solved. The possibility of a plastic hinge at the eccentric column-footing intersection was no more and the hogging moments in the footing was no more and likewise the floor was safe.

Now all the contractor needed was for me to specify the reinforcement and concrete grade for the new base beam. I had to do a bit more calculations for this.

To my surprise when I went into my reference books, in the foundations section, there I saw it; in the book, this kind of arrangement was called strap footings. In otherwords my challenge was not new, many others had faced this same problem and my work had been made even more easier at calculations. Whoa, talk about ingenuity. Engineers are never taught that in school, are they? If is the foundation for design and construction, isnt it?

ciao!

Nathan.
E.Africa(uganda).
MSCE, BSCE.
M_UIPE, M_IABSE.