Concrete Sweating: What is it and How to Prevent it

Concrete is used for all kinds of construction works these days. It is the first choice for building supports and beams because of its excellent load-bearing capacity, tensile strength, and longevity. However, nothing is a hundred percent impervious to weather effects, and neither is concrete.

Concrete Sweating, or more technically known as SSS (Sweating Slab Syndrome) occurs when water droplets are accumulated on the surface of a concrete structure. The phenomena occur generally overnight and may look like the concrete structure is sweating, hence the name. This can be a potentially dangerous issue in some cases.

Reasons for Concrete Sweating

There can be two main reasons why a structure is showing the SSS - dew point and subsurface moisture. Let us discuss them below.

Dew Point

When you take a soda out of the fridge and keep it out for a while, the soda bottle or can starts sweating. The same thing happens with concrete as well, especially overnight. A concrete surface is rather cooler than the air in contact with it. When the concrete is cooler than the dew point (the temperature at which the water vapor in the air starts to condense into liquid), the moisture in air sticks to the concrete. This, in turn, starts forming the water droplets. Which, to uninformed eyes, looks like as if the concrete has started sweating.

Subsurface Moisture

A much rarer phenomenon, this occurs when the concrete itself retains some moisture inside it. When the concrete is formed, much water is used to set the cement. All that water gets absorbed to form the crystals that harden the concrete. But the issue is, this process can go on for a long time. Initially, most types of cement can set in a day, but they harden over a long time - over weeks, even months. While the composite is hardening, the hydrostatic pressure inside them rises a lot. This, in turn, pushes the water out of the concrete slabs or structures. In this case, you can say that the concrete really does sweat, in view that the water comes from inside, not outside.

There can be some secondary reasons for SSS. For example, if the concrete slab is adjacent to wetness (wet soil or water body), the capillaries in a porous concrete can suck up moisture from the wet surface to the dry surface. Also, if the concrete mix has salts in it then due to their hygroscopic nature the salts will attract water into the concrete. The material on top of the concrete can also be the culprit in attracting water, like dust or rubber.

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Some important checklists for RCC slab and beams

The following checklists are extensively utilized for RCC slab and Beams.

1. Examine the bottom line, level & width of beam properly.
2. Examine the side line, level & plumb of beam properly.
3. Beam to beam measurements should be examined according to architectural drawings.
4. Individual level & diagonal of each slab bay should be examined properly.

5. The thickness level of slab should be marked with nails on the peripheral beam’s exterior sides.
6. Examine the thickness of slab and depths of beam properly.
7. Support props for slab & beam bottoms should arrange in line & plumb. Bamboo bracing should be accomplished at around 4′ ht from floor level. Support props for double staging terraces should be examined cautiously.
8. Line of external /peripheral beam’s sides should be examined & cross supported to get rid of buldging out of sides.
9. Junctions of columns & beam should be verified to make them water resistant.
10. De-shuttering oil should be provided to beam/slab shuttering.

11. Formwork of stair case should be examined for dimensions of tread and riser, level of treads, plumb of risers.
12. Reinforcement should be examined for beams and slab as per R.C.C drawing
13. Ensure to provide exact cover for bottom /sides of beams.
14. Proper cover should be provided for slab.
15. Electrical points, electrical piping (conduits)/fan hooks should be examined as per drawing.
16. Reduction of column according to drawing should be performed if any.
17. There should be exact numbers of chairs should be arranged for slab.
18. Dowels (if any) should be arranged for elevational feaures / future expansion.
19. Parapet (Pardi) bars should be provided for balconies/staircase etc.

20. Ring (stirrups) should be arranged at the free end of each column reinforcement.
21. Distances among plates /planks should be filled. Taping should be performed at ply joints for the protection of ply shuttering.
22. Before starting pouring work, consent of the architect and R.C.C Consultant should be obtained.
23. Prior to start concreting work, verify the accessibility of necessary labour strength, mixer, lift, vibrators, masons, weigh batcher, diesel/petrol and plastic sheets etc before start of concreting.
24. Hidden beams /inverted beams/cantilever beams should be examined properly.
25. Based on the approved drawings, verify the sunk.
26. Packing underneath support props should not be provided. As an alternative, single wooden plank should be inserted as packing.
27. For large slabs, exact location of concrete joints should be determined beforehand as per approval of RCC consultant.
28. Accessibility of raw material for concrete /RMC per grade of concrete, water , electricity should be examined beforehand prior to start concreting work.

29. Initially, concreting should be performed for the beams & then slabs.
30. Compaction of concrete should be accomplished with vibrators & tamping rods.
31. The top level of the slab should be completed with mason & there should be restrictions to walk on the fresh finished concrete.
32. Carpenter should be provided under the slab shuttering throughout concreting to keep the form work tight.
33. For protection against rains, large plastic sheets should be used to wrap finished concrete.
34. Cast 6 cube moulds for testing.
35. Curing of slab should be accomplished with ponding method by making ponds in cement & sand mortar (1:10) of size around 5′ X 5′. Curing of beams and slabs should be performed for 7 to 10 days or as suggested by the consultant.
36. Deshuttering of the exterior sides of the beam should be accomplished after 24 hours . Deshuttering of the inner sides of beam should be accomplished after 48 hours . Deshuttering of the beam bottoms should be accomplished after 14 days for beam lengths up to 3 M or as per suggestions of the consultant. Deshuttering of the slab should be performed after 7 days for slabs up to 3 M span or as directed by the consultant.
37. Finishing of honeycomb should be accomplished cautiously in front of engineer the next day.
38. Hacking of the beam sides, beam bottoms, slab bottoms should be accomplished within 1 or 2 days from deshuttering.
39. Date of casting and the number of slab should be painted on the front side beam.

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Construction Method Of Concrete Slab On Grade

Slab on grade belongs to concrete floor slabs which are poured at grade or ground level to develop a foundation for a home. Prior to start the construction, contractors excavate the soil adjacent to the area where the foundation should be constructed and ensure that the ground has sufficient strength to support the structure.

Normally, the periphery of the slab is very dense as compared to the rest of the surface. This section has similarity with footer that facilitates to circulate the weight of the exterior walls uniformly over the soil underneath the structure. Slab on grade foundations are suitable for the areas where the soil is unusable for crawl spaces or basements.

Grade slabs are provided in areas where the ground is not solidified. This type of slabs may or may not include reinforcement in it. The inclusion of reinforcement depends on the floor loads and local building codes.

The thickness of Grade Slab should be at least 4 inches. If porosity exists in soil, the thickness of the slab should be raised. To maintain safety, a layer of gravel & bitumen should be placed on earth prior to arrange concrete slab to stop the penetration of moisture content into the slab.

Slab on Grade is categorized as follow:

1. Supported Slab on Grade
2. Monolithic Slab on Grade

Supported Slab on Grade / Grade Slab: Supported grade slab or slab on grade foundation should be used when the conventional footings are already set up on site to uplift the columns. Under this system, the wall is laid on a footing and the grade slab stands on a layer of gravel and moisture barrier.

The formwork applied for plinth beams operates as batter boards for slab mould. There is an expansion joint among concrete slab and wall to reduce the stress throughout high-temperature days. Control joints are set in a planned grid with chalk lines to manage occasional cracking on the slab.

Monolithic Slab on grade: There are no footings for monolithic grade slab, the concrete slab itself functions as a footing for the building; and the columns, walls are uplifted from the grade slab. This type of slab is structured with batter boards around the slab based on the plan and the concrete is poured inside batter boards. These batter boards operate as a mould to detect the slab corners.

Grade slabs normally stand on the layers of gravel and moisture barrier. These layers can resist penetration of water into the slab to develop surface cracks.

The periphery of the grade slab is very dense as compared to the rest of surface. This dense section operates as a mini footing and facilitates to circulate top loads more consistently over the adjacent soil.

Construction Method: Prior to cast slab on grade, the excavation of earth is done to the desired depth along with compaction to drive out air voids. Batters are leveled and provided in exact location based on the plan prior to concrete pour. These boards function as a concrete mould to facilitate detecting the slab corners.

After that, soil investigation is performed to design the thickness of the slab. After obtaining the results, the layers of gravel and moisture barriers (bitumen) is again poured on the ground. These layers are used as a sub-base for slab and resist the infiltration of moisture into the slab.

The thick concrete is poured at the edges to form an solid footing and reinforcement rods are placed to increase the strength of the edges.

To reduce random cracking on the surface, the concrete should be cured and dried for long times.

The expansion joint should be arranged among the wall and slab. The control joints on the slab are leveled with chalk lines prior to pouring which can check random cracking.

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Basic variations among main bars and distribution bars

In this exclusive civil engineering article, you will know the difference between the main Bars and Distribution Bars in slab reinforcement.

Main bars and Distribution bars are vital terms which are found in slab reinforcements. In this civil engineering article, you will come to know the variations among main bar and distribution bar in slab as well as where these bars should be arranged in R.C.C slab.

MAIN BARS IN SLAB:

1.  The main reinforcement should be arranged at the shorter extent of the slab, as in the shorter extent slab has to undergo High bending Moment that is called sagging or positive bending moment.

2. nbsp; Main reinforcement bars have to resist and bear all the tensile stresses, bending moment (Sagging), and superimposed load (Dead load) which are formed at the shorter extent of the slabs.

3.  Main reinforcement bars are arranged in one way slab in one side (At shorter extent), but in two way slab, the bars are arranged in both ways.

4.  In Flat plate slabs the main bars are arranged in one direction at bottom of the distribution bar (in shorter extent).

5.  Main bars in the slabs should not be under 8 mm while applying (H.Y.S.D) or 10 mm for plain bars.

DISTRIBUTION BARS IN SLAB:

1.   Distribution reinforcement bar should be arranged at the longest side extent of the slab.

2.  Distribution bar are specifically created to allocate the super imposed load consistently or resist the Shrinkage stresses which are formed because of fluctuation of temperature in winter or summer.

3.   In Flat plate slab the, the distribution bars are arranged in one direction at top of main bar (in longest extent).

4.   The distribution bars should not be under 8 mm in a diameter or not in excess of 1/8 of the thickness of the R.C.C slabs.

5.   The distribution bars are arranged to retain the mesh in exact location and keep the center to center c/c, bars spacing among main bars.

VARIATION AMONG BETWEEN MAIN BARS AND DISTRIBUTION BARS:

1.  The Main bars are generally arranged at the bottom of distribution bar in slabs whereas distribution bars are arranged on the top of the main bar.

2.  The Main bars are arranged in the shorter extent of the slabs whereas distribution bars are arranged in the longer extent of the slabs.

3.  The main reinforcement is arranged to resist the bending moment, tensile stresses and superimposed load whereas distribution bars are utilized to allocate the load uniformly as well as withstand the shrinkage stress (Temperature discrepancy) or retain the mesh in exact location.

4.  Main bars in the slab should not be under 8 mm when (HYSD) or 10 mm bars are used. But, when, plain bars and the distribution bars are used, it should not be under 8 mm diameter and the bar should not be in excess of 1/8 of the thickness of the slab.

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Brief overview of composite slabs and columns

Composite slabs contain reinforced concrete cast on top of profiled steel decking that functions as formwork all throughout construction and external reinforcement at the final stage.

Composite slabs:

• Comprise of profiled steel decking with an in-situ reinforced concrete topping.
• The decking (profiled steel sheeting) not only functions as permanent formwork to the concrete, but also arranges adequate shear bond with the concrete in order that when the concrete attains strength, the two materials function compositely side by side.
• Spacing should remain among 3 m and 4.5 m onto supporting beams or walls.
• When the slab is unpropped at the time of construction, the decking alone can withstand the self weight of the wet concrete and construction loads. Succeeding loads are implemented to the composite section.
• When the slab is propped, all of the loads should be countered by the composite section.
• The slabs are generally designed as simply supported members in the normal condition

Profiled steel sheeting:

• Depths vary from 45 mm to over 200 mm
• Yield strengths vary from 235 N/mm2 to minimum 460 N/mm2
• 0.8 mm and 1.5 mm thick
• The different shapes offer Interlock among steel and concrete
• Decking may also be applied to make the beams stable against lateral torsional buckling all through construction.
• Make the building stable entirely by performing as a diaphragm to transmit wind loads to the walls and columns.
• Temporary construction load generally governs the choice of decking profile.

Composite Columns: A steel-concrete composite column stands for a compression member that includes either a concrete encased hot-rolled steel section or a concrete filled tubular section of hot-rolled steel. The existence of the concrete is permitted in two ways.

• Protection from fire
• It is assumed to resist a small axial load
• Composite columns minimize the effective slenderness of the steel member that improves its resistance against axial load.

The bending stiffness of steel columns with H-or I-section is much higher in the plane of the web (‘major-axis bending’) than in a plane equivalent to the flanges (‘minor-axis bending’). The ductility performance of circular type of columns is considerably superior as compared to rectangular types. It is not necessary to arrange additional reinforcing steel for composite concrete filled tubular sections. Corrosion protection is arranged with concrete to steel sections in encased columns.

When local buckling of the steel sections may be detached, the cutback in the compression resistance of the composite column because of overall buckling should be permissible positively. The plastic compression resistance of a composite cross-section demonstrates the maximum load that can be implemented to a short composite column.



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How to measure minimum bar spacing for Bundle Bars in Cast-in Place Concrete as per AASHTO provisions

Minimum Bar Spacing: As per AASHTO LRFD, section 5.10, the minimum bar spacing for bundled bars should be measured on the basis of the acquired diameter rather than computing from individual diameters.

As for instance, if there are 2 nos. 32 mm dia bars, the similar diameter in accordance with 2×32 is 45mm. Therefore, 45 should be employed to utilize the following clauses from AASHTO.

For 2×32 dia bars, clear spacing should be provided as ~68mm for Cast-in Place concrete and 60mm for precast concrete.

Refer following Clauses from AASHTO LRFD 5th Edition 2010

5.10.3.1.1—Cast-in-Place Concrete

For cast-in-place concrete, the clear distance among parallel bars in a layer should not be under :

5 times the minimal diameter of the bars,
5 times the maximum size of the coarse aggregate, or 1.5 in.

5.10.3.1.2—Precast Concrete

For precast concrete fabricated under plant control conditions, the clear distance among parallel bars in a layer should not be under :

The minimal diameter of the bars,
33 times the maximum size of the coarse aggregate, or 1.0 in.

5.10.3.1.5—Bundled Bars

The number of parallel reinforcing bars bundled in contact to function as a unit should not go beyond four in any one bundle, apart from flexural members, the number of bars greater than No. 11 should not go beyond two in any one bundle.

Bundled bars should be attached within stirrups or ties. Individual bars in a bundle, cut off inside the extent of a member, should be abandoned at several points with minimum a 40-bar diameter stagger. Where spacing limitations are dependent on bar size, a unit of bundled bars should be considered as a single bar of a diameter taken from the corresponding total area.

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Details about R-value and U-value of Concrete Slab

The conduction of heat regarding the materials utilized in its construction is measured with the thermal conductivity coefficient alias k-value (W/m.K), of the materials used in its construction. It belongs to the rate at which heat moves through a material among points at dissimilar temperatures.

The thermal resistance alias R-value (m2K/W), is computed by dividing the thickness of the material (in metres) with the k-value. From this the thermal transmittance alias U-value (W/m2.K) concerning a building material is measured like the inverse of the sum of the R-values of the component parts and adjoining air layers.

R-value stands for the estimation of concrete slab (or other material) strength to counter heat flow i.e. it calculates the potency of insulation or thermal resistance. However, U-value stands for the estimation of heat transmission throughout concrete slab from ground into the closed space or oppositely.

Since, thermal insulation fluctuates contrariwise with density, lower density concrete offers superior insulation as compared to greater density concrete. With the purpose of determining the strength of the reinforced concrete slab to withstand heat transfer, it is necessary to estimate R-value and U-value of the reinforced concrete slab under consideration.

The method for estimating R-value for Concrete Slab: A perfect R-value for a normal concrete slab is computed with an R-value, the thermal resistance per inch of thickness, among 0.1 and 0.2 and multiplying it times the slab thickness. The value of R is determined with the following equation provided by ASTM C 168:

Here, the temperature variation (among exterior and interior of concrete slab) is provided in degrees Fahrenheit, the area is given in square feet, the time in hours, and the heat loss in Btus.

ASTM C 168 also offers two supplementary expressions to measure R-value and is available in ASTM C 168 document.

The R-value imperial unit and metric unit are given below:

Computation of u-value for Concrete Slab

The U-value for a concrete slab (and any other building material) stands for the inverse of its R-value and is computed with the formula given below:

The U-value unit is the inverse those of R-value:

Note: There is difference among the American Standard and European Standard for R-value and U-value. Therefore, to transform an American R-value into a European U-value, divide 1 with the R-value, then multiply the result by 5.682 whereas transforming a European U-value to an American R-value, multiply with 0.176, then divide 1 by the result.



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Why pouring concrete over present concrete slab is not recommended

It takes huge time and labor to remove a subsisting concrete slab. In this regard, the most suitable process is to pour a new layer over the subsisting slab.

Thus, the requirement for labor will be reduced significantly as well as the money and resources will also be saved greatly. But, once the new layer is poured perfectly, it will only be as secure and durable similar to the older slab under it.

Increases the Level: The level will be increased by several inches while pouring a new layer of concrete over a subsisting walkway, patio or porch. If the slab puts up to a door, there may not be required clearance for the door to open with the lifted surface.

Towards a walkway, increasing the level by several inches can give out its alignment with the driveway, steps or another structure. When a slight ramp is added from the driveway to the increased surface, a trip hazard is reduced and the debris is retained from being collected in the corner.

Fewer Years of Service: A well-poured concrete slab containing a deep, strong foundation can survive for 30 to 40 years. Pouring concrete over old concrete rather than directly over a new gravel foundation restrains the scope to enhance the longevity of the slab.

The longevity of the new concrete is mainly dependent on the condition of the subsisting slab. If the foundation under the slab is not strong, the new concrete may sink or produce deep potholes.

Bonding: If new concrete is attached with the subsisting slab, cracks may occur. Retaining the new concrete from tying to the subsisting slab, new damage can’t develop as well as any damage in the old slab from extending to the new one. It makes both slabs adaptable to shrink and enlarge when temperatures change. To get rid of bonding, plastic/sand or other long-lasting material are arranged among the two layers of the slabs.

Maintenance: Due to its robust strength and low maintenance cost, the concrete is becoming popular. A slab poured over a subsisting slab may experience frost heave damage and cracks. The damages should be repaired immediately as soon as they form so that they can’t be expanded. The new layer must be sealed with deep penetrating sealer to get rid of water damage. If there are long, deep cracks, analyze the damage to find out any structural problem.



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Steel Buildings and their various benefits

Steel buildings are eco-friendly. Any steel structure integrates the organic material and for this reason mould and mildew infestations are not occurred. The steel buildings are 100% recyclable and can be used further.

Steel building construction is mostly recognized for their flexibility and stability. Steel buildings are designed for both permanence and impermanence i.e. they are utilized for storage throughout project execution or for long term preservation of machinery or goods. The steel building can provide the following benefits :-

1. Easy Set Up: The steel frames are fabricated perfectly to adapt collectively with one end skidding into the other. No special fasteners are necessary as well as cutting, retaining, and hammering concurrently long, immense and bulky planks.

2. Cost effective: As the steel is perfectly slashed at the time of manufacturing, no waste occurs in construction site. Less salary is disbursed due to requirement of fewer employees.

3. Environmentally Friendly: The steel buildings are environmentally friendly and they provide good benefits for construction. Steel is the most reprocessed material and several manufacturers utilize recycled steel in all of their steel building materials.

4. Energy Savings: Energy efficiency is another good aspect of an environmentally friendly building. In steel buildings, there are window placement, Tinted Windows, Insulated Frames, Vapor Retarders between the foundation and concrete slab.

5. Safe and stable: Steel frame buildings have strong resistance strength against flame as compared to wood framed constructions. Steel can also resist the attack from termites, bugs or rodents as well as mold or fungi.

It does not require any type of chemical to maintain it’s longevity. A steel frame building is efficiently grounded and less likely to be hit or damaged by lightning.

6. Superior construction quality: A steel frame building does not deteriorate in due course and weaken like wooden structures become over time. So, no need to worry about fragile spots. Steel has also good resistance capacity against corrosion. It is dimensionally steady and there is no distortion with climate changes.

7. Longevity: Steel contains heaviness ratios of any building material. It never buckles, divides, distorts, rotates, chinks, rots or splinters. It’s weight is less as compared to timber. It is can be handled easily and built up with specifically when lifting partitions and roofs.



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Various types of notations used in the construction of concrete culvert design

The following notations are used in the drawing of concrete culvert design.

With notation, it is possible to make clear communication among various project stakeholders. Notation helps in avoiding mistakes in any construction project.

A’ = The valid contact area of a footing, measuring unit is in square metres
A = A detailing dimension for culverts that contains skewed ends, measuring unit is in mm
B = Depth of the bottom slab of a box culvert, measuring unit is in mm
B = Gapping among adjoining bars with reference to detailing tables, measuring unit is in mm
C = A coefficient that is applied in finding out the quantities of reinforcing bar.
CANBAS = Canadian Bridge Analysis System
c’ = the valid cohesion among the base of the footing and the soil at the ULS, with reference to CHBDC. kPa
CHBDC = Canadian Highway Bridge Design Code, 2000 Edition
CGSB = Canadian General Standards Board
F = Width of footing for open footing culverts, measuring unit is in mm
F1 = A reinforcing bar spacing factor, measuring unit is in mm-1
HULS = maximum factored horizontal reaction at the level of the base of the footing at the ULS, kN
Lc = Culvert length that is calculated the longitudinal axis, measuring unit is in m
OCPA = Ontario Concrete Pipe Association
OMBAS = Ontario Modular Bridge Analysis System
OPSS = Ontario Provincial Standard Specifications
S = Culvert distance that is calculated perpendicular to the longitudinal axis of the culvert, measuring unit is in mm
SLS = Serviceability limit states, in accordance with CHBDC
T = Depth of top slab of culvert, mm tan φ’ effective friction coefficient for concrete cast against soil.
ULS = Ultimate limit states, with reference to CHBDC
V = Unfactored vertical reaction because of the dead load of cast-in-place concrete and soil fill, at the level of the base of the footing, kN
VSLS = Maximum vertical reaction at the level of the base of the footing at SLS, kN
VULS = Maximum factored vertical reaction at the level of the base of the footing at ULS, kN
W = Depth of wall of culvert, measuring unit is in mm
Γ = The extreme angle among the normal to the longitudinal axis and the end of the same culvert, degrees
φ’ = The valid angle of internal friction, with reference to CHBDC, measuring unit is in degrees
θ = Skew angle of culvert, degrees



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Benefits of precast concrete construction

Precast concrete is one type of construction under which casting is done in a recyclable mould or “form” and cured in a controlled surrounding as well as transmitted to the construction site and hoisted into place.

As precast concrete is developed in a controlled surroundings (precast plant), it becomes easier for plant employers to cure it perfectly and supervise carefully. Various types of precast concrete forming systems are available for architectural applications which vary in size, function and cost.

The precast concrete provides huge benefits due to the superior quality of the material formed in controlled conditions, as well as the lower cost of developing large forms utilized with concrete poured on site. It is primarily applied in the erection of buildings with repetitive design and components, like schools and apartments.

Given below, a wide array of benefits for utilizing precast concrete construction:

• Reduced Construction Time and Cost
With precast concrete construction, it is possible to save significant time as well as minimize the risk associated with loiter of project and prospective financial losses. Precast design and fabrication of elements begin when the construction site is under survey or earthworks. Because of the controlled surrounding of the casting area, production is not impacted with weather conditions. With the application of large precast panels, the time is curtailed significantly for the completion of the structural works so that other trades like painting and electrical wiring can be started quickly.

In traditional construction method, various laborious works like formworks, scaffoldings and curing are required to form a structural element. In precast concrete construction method, structural elements are formed in manufacturing plants whereas other activities are started at the construction site. At the time of requiring structural elements, they are delivered to the site right away and accumulated on regular basis, to build up the structural frame and encircle the building. In precast concrete manufacturing plants, there are modern machineries controlled by various technicians to look after specific production process.

• Superior quality and aesthetical value of products
Precast products are fabricated in a casting area where some vital factors like temperature, mix design and stripping time should be closely monitored and managed to make sure that the quality of precast products are superior as compared to cast-in-situ concrete. Significant amount of money will be saved as no rectification works are required. Because of factory-controlled prefabrication environment, various combinations of colours and textures are employed easily to the architectural or structural pieces. An extensive range of sizes and shapes of precast components are developed to offer good flexibility and fresher appearance to the structures.

• Cleaner and safer construction sites
The precast elements can significantly minimize traditional formworks and props. Precast construction also reduces the problem of site wastages and the associated environmental issues. A secure working platform is created for workers to act on with the prefabricated products. Requirements for workers and materials are also significantly minimized at the construction sites. By following just-in-time principles, the precast elements are preserved at the factory yard unless the site gets prepared for installation. There will be less wastage at both factory and construction sites because the elements are developed in the plant and mostly designed to be redundant.

• Superior unobstructed span
With the application of pre-stressed precast solutions like the Hollow Core slabs and Double-T beams, superior unobstructed span is obtained as compared to the traditional reinforced concrete elements. Bigger open space is created with fewer beams and columns. It is mostly suitable for the construction of places of worship, warehouses, halls, car parks, shops and offices.

For more information, go through the following link ukessays.com



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Build a concrete slab footing of modern buildings

A concrete slab is a common structural element of modern buildings. Horizontal slabs of steel reinforced concrete, typically between 100 and 500 millimeters thick, are most often used to construct floors and ceilings, while thinner slabs are also used for exterior paving.

In many domestic and industrial buildings a thick concrete slab, supported on foundations or directly on the subsoil, is used to construct the ground floor of a building. In high rise buildings and skyscrapers, thinner, pre-cast concrete slabs are slung between the steel frames to form the floors and ceilings on each level.

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Reinforcement Of Foundation Walls And Footers

Now-a-days various residential constructions are based on either concrete slabs-on-grade or on concrete or masonry foundations. There are various types of foundations, each of which offers both the potency and solidity to sustain the weight of the structure, its contents and occupants, as well as wind and snow loads which are transmitted to the foundation through the structure.

Zachary Francis comes up with a useful construction video tutorial on Reinforcement of foundation walls and footers. By watching this construction tutorial you will gather knowledge on the following topics :-

• Who is responsible to set up steel in both the wall and the footer Sorts of steel should be utilized in light frame construction

Where to collect the information essential to operate the tablets

• Where should be the tablets utilized and how to ascertain the type of wall as well reinforcement for utilizing

• How important is the soil type and types of rebar utilized in different foundation types

A robust foundation together with perfectly set up footings of acceptable size to defend the structure and resist extreme settlement, is necessary for the satisfying performance of buildings along with raised floor systems.

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Some Essential Steps To Construct A Wafflemat Foundation

This is a 3d animated construction video based on a Wafflemat foundation. In this video, you will be familiar with six easy to follow steps for developing the foundation from clearing the pad to installing the separate Waffleboxes, to pouring the concrete and eliminating the form boards.

Wafflemat is one of the most recognized concrete foundation forming system useful for residential and light commercial space. This system is applicable for expansive soil as well as other soil types with superior slab hardness.

Wafflemat forms a pattern of deep voids on the underneath of concrete foundation slabs. Waffleboxes are used to develop the voids. Waffleboxes are created with reprocessed plastic. Concrete is poured over the Waffleboxes to construct the slab as well as a set of narrow beams in two directions among the Waffleboxes. The beams contain center-to-center dimensions that remain within 4’-2”. The beams directly provide support to the foundation on the soil. They produce a very inflexible foundation slab.

In order to develop a Wafflemat foundation, a clean and level pad is necessary, as the system sets directly on grade. No need of pre-soaking.

Note: Foundations which are formed with the Wafflemat system, should be designed with a licensed Civil or Structural engineer having good knowledge in the design of concrete foundations on expansive soil, through soil test data submitted by a licensed Geotechnical engineer.

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Some Useful Guidelines for Concrete Slab Design in Visual Analysis 9.0

Jon Lovgren, the Engineer at Beaudette Consulting Engineers, Inc., has presented a useful construction video that shows how to create the design of a concrete slab with Visual Analysis 9.0, a powerful software for structural engineers. Learn the detailed design procedures toward both manual and auto-meshed plates, together with the definitions of the input parameters and general hazards and drawbacks of the procedure.

Visual Analysis is a construction program ideal for structural analysis and member design of standard beams, columns, frames, trusses and building models. With Visual Analysis the structural engineers can get key solutions for big or unusual structures effortlessly and rapidly.

This construction software is used to examine both lateral and gravity loads in a single model.

Visual Analysis simplify the process for developing models with sketching, DXF import, copy & paste, parametric formation of general components (frames, tanks, walls, bracing, floor systems, etc.), import from spreadsheet or other tools, and BIM. Blend materials in your models: steel, wood, concrete, cold-formed and aluminum.

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Published By

Rajib Dey

www.constructioncost.co

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