This short note is essentially useful for technical personnel and engineers, and may not serve much purpose to the majority of common people because of certain core civil engineering terms used to explain. However, like always, BRICKS-n-mortar Edesk has tried to explain in utmost simpler terms and language so that a non-technical person interested in knowing may also understand if he/she may so desire. This note is published on request of 'Chan Gul', one of our long-time avid subscribers.

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Slab construction over deck sheet forms

What, in the first place, is meant by a 'slab' in the building design concept?

Before proceeding further, it would be prudent to explain for the understanding of our non-technical readers, as what is meant by a 'slab' in the technical jargon.

A slab is essentially a two-dimensional reinforced or non-reinforced cement concrete structural element of the modern building design concept that serves the purpose of a floor and/or a ceiling and/or a landing base. It is termed a two-dimensional structural element as it spans across the length and width (or trigonometric components of horizontal and/or vertical planes thereof like that in case of inclined roofs, stair waist slabs, etc.).

The most common examples of slabs being the floors, roofs, ramps, concrete staircases, etc. The slabs may or may not have composite beam(s) network associated with them, which provide inherent support and rigidity to the slabs per se.

Classification of Concrete Slabs

The classification of concrete slabs is basically done based on the following factors:

• based on the position of slab :
  i.e., whether the slab is to be constructed ..
  
  
  • directly resting over the well compacted ground (called Slab-on-grade or Slab-on-ground). Such slabs can also be simply termed as ground floor slabs in layman's language as these are cast directly over well-rammed and compacted sub-base (ground), and serve the purpose of floors resting over the ground. That is why such slabs are commonly called as 'Ground Floors'.
    
  • elevated slabs that are constructed somewhere higher on the structural frame (like first floor, second floor, roof, etc.)
  
  
• based on the shape and geometry of the slab :
  i.e., whether the slab is ..
  
  
  • square, or
  • rectangular, or
  • circular, or
  • annular ring slab
    
  • triangular, or
  • any other geometrical shape whatsoever.
  • symmetrical slab
  • asymmetrical or elongated slab
  • dome slab
  • curved slab
    
  
  
• based on the end conditions (end supports) of the slab :
  i.e., whether the slab is a ..
  
  
  • continuous slab
  • discontinuous slab
  • simply supported slab
    
  • fixed end slab (comprising multiple conditions with options like fixed at one end, two ends, three ends, all four ends, opposite ends, adjacent ends, etc.)
  • cantilever slab
    
  
  
• based on the reinforcement design principle of the slab :
  i.e., whether the slab is a ..
  
  
  • one-way slab
  • two-way slab
  
  
• based on the construction practices or usage or rigid design principles :
  i.e., whether the slab is a ..
  
  
  • flat slab
  • sunken slab
  • raised slab
    
  • waffle slab
  • ribbed slab
  • corrugated slab
  • staircase waist slab
  • deck-resting slab
  
  
  

  

  Concrete being poured for roof slab construction

Brief definition / explanation of the various types of Concrete Slabs 

The above mentioned various types of concrete slabs shall be discussed in brief in the next concluding part of this post titled: Concrete Slabs | Common types of building Slabs | Slab basic design concept --- (PART-2/2)
that shall be published here on BRICKS-n-MORTAR(dot)com shortly. Do check in for the details if find the topic interesting.

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Post title: [TechTalk]: Concrete Slabs | Common types of building Slabs | Slab basic design concept --- (PART-1/2)

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Jennifer Cole (jenn...12@...org) asks us via BnM's feedburner platform: 

"WHAT IS WEB CONTENT SYNDICATION'?

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Quoting one of the nicely and simply explained meaning of web content syndication available at ehow(dot)com ... 

"Content syndication is truly a broad area. Many consider syndication simply putting an RSS feed or two on their Web site and nothing more. But content syndication is much more than that.

Anytime your content is reproduced anywhere, it is considered syndicated.

For example, writing articles about your Web site and submitting them to article directories is a great form of syndication because, in turn, other web sites will reproduce that content and provide you with another link back to your Web site. One article submitted to many directories can literally end up on thousands of web sites after several months.

Social bookmarking is also another hot option. Promoting your web site in public on their social bookmarking pages is a quiet way of saying that they love your web site. In return, other surfers will see their pages and visit your Web site. Once again, a little syndication can go a long way.

Choosing the right method for your website, by taking a brief look at one's goals and quality/quantity of the content published over the webspace, content syndication can easily be shaped into an easy-to-execute promotion plan."

[Note: Those interested in reading the article in full may surf through the same at http://www.ehow.com/how_2003263_select-syndication-method.html]

In a nutshell:

• Web content syndication is an internet based application and/or method primarily utilized for the simple purpose of republishing / reproducing / re-blogging / web link offering to third party websites
• Main purpose is to either provide customized updates/ feeds of a particular website to its registered subscribers, or to offer link-baits on other websites, blogs and social media sites (like Twitter, Digg, StumbleUpon, Del.ico.us, Yahoo! buzz, Google Reader, and the likes) to gain viral marketing and receiving possible linking back web traffic.
• Intended purpose of most of the genuine websites and blogs [like us, of course!  :-)  ] is also to provide link/ content information to their respective readers, visitors and subscribers by means of such Web Content Syndication.
  

BRICKS-n-MORTAR 's major feed syndication links:
(for ready reference)

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Related previous posts of similar post interest/ tags/ labels:

• [PART-1 / 2] : Opt to Receive blog updates by 'RSS Feeds Syndication' or 'Mailbox Subscription' methods?

• [PART-2 / 2] : Opt to Receive blog updates by 'RSS Feeds Syndication' or 'Mailbox Subscription' methods?

• Useful Utilities-n-Softwares

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• PART-1 / 2 : Opt to Receive blog updates by 'RSS Feeds Syndication' or 'Mailbox Subscription' methods?
• [Web-Share]: Sharing Useful RSS Feed links serviced by 'New Institute of Civil Engineering, UK'
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• About Shanghai World Expo 2010 & the amazing life-sized Pavilions constructed by Countries of the World
• [Q&A]: Reg. new comment received on Brick Masonry work | "Why bricks be soaked in water....

BRICKS-n-MORTAR's chief editor, Shelly's reply to recent comment received from Ms. Selvie on our earlier published post "[Q&A]: Brick Masonry work | "Why bricks be soaked ...":

Selvie wrote:

What if bricks are soaked more than required time? How to determine the optimum time of soaking? Please reply

Shelly replies:

Dear Selvie,

Like we said in the post itself, normally, about 2 to 6 hours of soaking of bricks in a tank full of potable water is suggested.
Otherwise, in case of paucity of time, a minimum period of one hour prior to bricks being laid must be adhered to.

In case the bricks have been lying in water for substantial part of time, say like one or two days or even more, ensure taking out the bricks and making them skin dry under sun or in the open air so that extra water retained in the pores of the bricks be let off.

One more thing to ensure after prolonged soaking of bricks is to take a visual note whether any white, yellowish or other patches have come up on the surface? Such patches, if they do come up on the surface, indicate presence of un-reacted lime in bricks, which is not desirable in any case (called efflorescence of bricks).

Hope this answers your query.

Shelly
BRICKS-n-MORTAR
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Related original post: [Q&A]: Brick Masonry work | "Why bricks be soaked in water before placing them?"

Related stuff of interest : 
             

One of BnM's active subscribers, Chan Gul, asks via email...

What is Shell and Core Construction?

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Team BnM answers... With the building heights increasing and further increasing than what they used to be a century ago, and with newer methodologies being adopted for faster and safer construction practices the world over-- the integral civil engineering aspects like conceptualization, design, construction, interiors, etc. have also changed to suit pace. We all have been knowing since we look back into modern history, how buildings and houses were constructed as load bearing structures with foundations and walls predominantly constructed in stone and/or brick masonry. With further advancement of time and technology, reinforced cement concrete (RCC)/ structural steel/ structural steel+reinforced cement concrete composite elements formed framed structures became common, which were more stable and well engineered units. These framed structures adopted a typical construction pattern of casting the foundations, followed by casting the columns and beam networks, and eventually followed by casting of the intermediate and/or roof slabs. This engineering concept allowed the number of stories to increase over a particular plan area, which we normally call as multistoried buildings. However, now that the buildings the world over registering record-breaking heights while construction agencies finding ways to optimize costs and time curves involved, systems were designed in a fashion that allowed minimizing the construction time involved in raising the buildings without breaking the construction flow in respect of attaining the full building height (i.e., notwithstanding how many stories are there in the design, and how many slabs are to be cast in between for which, by conventional methods, the formwork has to be stopped at slab soffit (bottom) level, and then re-started post concreting and setting of the floor/roof slabs). WHAT IS SHELL & CORE CONCEPT OF BUILDING DESIGN & CONSTRUCTION? SHELL & CORE design and construction concept, on the other hand, designs the buildings and structures in such a way that allows the complete formwork (also called shuttering work in some parts of the world) for a particular level in plan to be made as a single unit that is slipped upwards with the help of 'jack & lift system' while concreting of the structural elements takes place continuously and gradually without stopping at intermediate floor levels. WHY THIS CONCEPT IS CALLED 'SHELL & CORE' METHOD? Under this concept of 'shell and core' design and construction, the buildings structures are defined under broad heads as

• CORE -- (the internal column-beam-wall systems that outline the various inside units on one particular floor level of the building in plan/layout, and which demarcate the internal boundaries of the rooms, halls, sanitary areas, ventilation areas (like passages, walkways, staircases, etc.)
• SHELL -- (the outermost peripheral wall system that ultimately provides outermost walled covering to the entire building in totality)
• INFILLS or INTERIOR ELEMENTS or MINOR ELEMENTS -- (these are the non-structural elements of the building that serve the essential purpose of architectural detailing units, finishing items, false partitions, and the likes)

To sum it up, the 'Shell and Core' building concept is to plan, design and build the core (inside) building which is covered or surrounded by shell (perimeter). Once the core and shell building elements are constructed, the internal architectural elements can be taken up gradually and continually. MAJOR ADVANTAGES OF 'SHELL & CORE' DESIGN and BUILD CONCEPT Some of the major advantages of using the 'shell and core' concept are:

• speeds up the whole design & build process
• facilitates economic and fast track design and construction method that saves a lot of time, efforts, and thereby, cost
• helps in planning, designing and constructing building layouts that optimally utilizes the overall available space
• most importantly, results in development of Green Buildings that are not only environment friendly, but also use minimal energy on a sustained basis
• such designs are suited for commercial buildings the most, besides residential & multi-storied builds of course, since it allows the internal smaller unit hirer/ purchaser to plan, design and build their own dwellings capitalizing upon the green strategies and methodologies adopted and implemented by the main property developers. This is important, since the smaller players can use the technology and 'greener' advantages of the building without worrying about exorbitant costs that otherwise could have not let them to adopt methods underlying the important of 'going-green'

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Ask us in case you also have any query relating to civil engineering, architecture, building design & construction, interiors, etc. Subscribe to get more such tips-n-bits, posts and articles delivered directly to your mailbox. Alternatively, subscribe to our RSS Feeds if you desire to access the content of this blog over any feed-reader of your choice. - - - Image sources: Image-1 (stephenson-ssc.co.uk) & Image-2 (jfe-steel.co.jp)

One of BRICKS-n-MORTAR's regular readers, Mr. B. Kumar asks via 'contact us' form...

"My mason soaks the bricks in water before placing them.  Why?  Is it right to do so?  Please tell a.s.a.p."

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Team BnM answers...

Image source: brickmasonry.info

Dear Mr. Kumar, the answer to your query is a big 'YES'.

Your mason is doing the absolutely right thing what he is supposed to do. Besides, consider yourself lucky that you've hired a knowledgeable mason since the fact remains that majority of the workmen do not adhere to this quality requirement for the simple reason that this practice, though very much required for attaining quality work, is time & efforts consuming exercise on its own. And, therefore, most of the masons hesitate to carry out this important and much needed exercise of soaking the burnt clay bricks before laying them for construction works.

Now, let us explain a bit as what is the significance of this procedure..

Red bricks, as what commonly these are called, are blocks of a mix of clay and other suitable constituents like silica, alumina, etc. that are wet-moulded, sun-dried and fire-burnt in desired shapes and sizes. The dried bricks become leather-hard and slightly porous in nature.

If these dry bricks are laid in construction of walls or other masonry works without soaking in water, they absorb the moisture from the cement mortar that is used to bind the brick courses. This ultimately may results in hollow & weak mortar joints that are not very strong in bond.

On the other hand, as a good quality practice, the burnt clay bricks should be soaked in water for adequate period so that the water penetrates to its full thickness and quench the un-slaked (un-reacted) chemical constituents /voids of the bricks to full extent.

Normally, about 2 to 6 hours of soaking of bricks in a tank full of potable water is suggested. Otherwise, in case of paucity of time, a minimum period of one hour prior to bricks being laid must be adhered to. Equally important is the fact that the soaked bricks should be removed from the water tank sufficiently in advance so that they are skin dry at the time of actual laying. Such soaked bricks are to be stacked on a clean place where they are not contaminated with dirt, earth, etc.

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Blog Post Title: [Q&A]: Brick Masonry work | "Why bricks be soaked in water before placing them?"

Related stuff of interest : 
              

Ask us if you also have any query relating to civil engineering, architecture, building design & construction, interiors, etc.
Subscribe to get more such tips-n-bits, posts and articles delivered directly to your mailbox. Alternatively, subscribe to our RSS Feeds if you desire to access the content of this blog over any feed-reader of your choice.

B-n-M's Q&A | December 2009 | (Series#1)

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Q: How do you hang a heavy mantle without cleats or corbels?  
A: First things first --- Any member that is to be hung (erected) must either be supported at end and/or in-between at least one place for stability and fixing purposes. 

The only other way to hang a heavy mantle, unsupported otherwise elsewhere than at the ends, is to fix it with the help of suitable anchor fasteners available for several reliable makes like Hilti, Fischer, etc. The structure to be hung must be fixed with suitably designed end plates in structural steel, which then can be anchored on to the receiving surfaces (ends).  

Q: What materials do you need to make a truss?  
A: To start with, let us first explain in very simple terms to all our readers as what a 'TRUSS' is.  

A truss is a structural member that is fabricated by means of joining various suitably designed members of desired parameters like length, section, material, weight, end connection system, etc. into a grid type shape. A truss usually takes advantage of the strength of triangular shaped units that are joined together by different means.  

The most common building materials that are used for fabricating trusses are structural steel sections, seasoned wood, hollow or solid pipes, bamboo, etc. The selection of the material essentially depend upon the load factor, type of use, material availability, etc. In some of the cases, even a combination of more than one material can be used.  

The most common type of trusses used in construction purposes are:

• King post truss
• Queen post truss
• Bowstring truss
• Attic truss
• Pratt truss
• Lenticular truss
• Gambrel truss
• Hip truss
• Fink truss
• Flat truss
• Howe truss
• Inverted truss

The most common uses / places where trusses are erected are:

• Roof supports
• Bridges
• Sheds
• As permanent beam supports (as against formwork)

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For more such informative posts and trivia, keep visiting us at: BRICKS-n-MORTAR.com  

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Question posted by one of B-n-M's readers, Robert Ravi in the comments section of one of our earlier posts titled: "[Readers' Q&A]: What's the Difference between Floor...":

>Hi,
That was a very good info. Please (tell me) what is the differnce in sq.ft rate normally between ground floor and first floor (excluding special elevation work) for an independent house
Regards
Robert
Posted by Robert Ravi to BRICKS-n-MORTAR.com at Sunday, August 16, 2009 1:12:00 AM IST

Team B-n-M answers...

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Dear Robert,
To be very frank, there is no hard and fast rule or law / guideline of government or an authority that decides what rates can be fixed for different floors of a particular building. On the other hand, the prices of floors are calculated/ quoted based upon a number of other usability and valuation practices that may also vary from place to place and time to time.

For the sake of simpler explanation, the standard and widely accepted basis of such valuation can be considered with respect to the following:

• Area usability factor --- Ground floor has usually more open area in the form of courtyards/ lawns/ parking space; while the top floor has in some of the cases roof rights. The floors in between have the set super area with no extended spaces. As such the ground floor and the top floor have a higher rate tag than other in between floors due to this aspect.
  

• Ease of usage --- The ground floor is the easiest to access. It pays especially for aged people and otherwise when one doesn't want to climb the stairs to get into one's home. The rate of ground floor, therefore, is higher than the other floors due to this aspect. The higher you have to climb up, the more is the decline in the rate (although it is a marginal decline).

• Other factor --- If the ground floor of a building is a bit intrusive or not free from the usual eyesores, or is not that appealing because of any factor, in such cases the first floor commands more premium that the ground floor.

Robert, since we do not know which type of building you have in your mind, or who the builders/ developers of the building are, we take an example of some of the key reputed builders' two-to-three-storeyed building on offer these days to give you an idea of the type of difference in the rate of a ground floor flat and a first floor flat. Do keep in mind that this may vary from place to place, or for builder to builder, or type of colony, etc.

In general,

• if the ground floor flat has certain facilities like front/ back courtyards/ lawn/ garden, etc., then the rate of the first floor may fall in the range of 85% to 90% as compared to that of the ground floor.
  

• On the other hand, in case there are only two floors in the building and the first floor has also got full or part roof rights, then the rates of the either of the floors shall not vary much.

Hope this gives you some insight and may help you in taking the appropriate decision. For any other information/ clarification, do let us know.

SUBSCRIBE to get B-n-M's updates and feeds right there in your INBOX. Enter your email ID here ...

Found this post interesting? Then check out other related posts : PropertyTalk

B-n-M

Question posted by one of B-n-M's readers, Muthiah in the comments section of one of our earlier posts titled: "[Readers' Q&A]: Difference between types of cement":

Hi!

Wan i know the difference of OPC and PPC cements

-Muthiah

Team B-n-M answers...

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Dear Muthiah,
This is a very common question people ask. As a quick reference, you can also go through the above-mentioned earlier post and its comments section to get the answer in brief.  Further, let us explain again for easy understanding of yours and all our other interested readers...

OPC (Ordinary Portland Cement) is the basic form of cement with 95% of it being the clinker and 5% being gypsum which is added as an additive to enhance the setting time of the cement to a workable 30 minutes odd or so.  This cement is the standard norm being manufactured and sold by cement manufacturers around the world. As the Understanding-Cement website puts it: "In particular, 'Ordinary Portland Cement' is the normal, grey, cement with which most people are familiar".

However, with changing times and with enhanced energy requirements and associated environmental implications that came along with, the thermal (coal based) power plants the world over started producing multitude of coal ash (commonly known as 'Flyash or Fly Ash'), which is a waste product otherwise, in the form of finely divided residue resulting from the combustion of ground or powdered bituminous coal or sub bituminous coal (lignite) and transported by the flue gases of boilers fired by pulverized coal or lignite.

Then, with the bitter fact the world faced about the disposal of fly ash becoming a serious problem in itself, and on the other hand this fly ash being found to have certain useful cementetious properties, the worldwide statutory and academic bodies allowed addition of up to 35% of fly ash in making the type of cement, commonly known as the Pozzolanic Portland Cement (PPC). This way, the waste product which could have become a serious environmental hazard, has now become a sought-after raw material for manufacture of modern day large-scale produced cement known as the Pozzolanic Portland Cement (PPC).

One common question relating to use of OPC / PPC that people usually ask us is:

Is PPC good to use for the construction of my house/ factory/ repair works/ heavy engineering works?

Some people have presumption that since PPC uses a waste product as an ingredient, it makes it less good than the good old OPC. However, on the other hand PPC has certain distinct advantages over OPC, as listed below:

• Low heat of hydration reducing chances of surface cracks
  
• Longer setting time making it more workable than OPC
• Ultimate strength higher than OPC
• Lower porosity imparting the concrete more water tightness
• Lower manufacturing cost compared to OPC
• Waste utilization making it more environmental friendly
  

Thus, it can be safely inferred that PPC (Pozzolanic Portland Cement) can be used invariably for all common uses that OPC (Ordinary Portland Cement) can be used including one's construction works, concrete works, repair works, finishing works (plastering, flooring, etc.), and the likes.

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