Concrete floor slabs on grade are subjected to a varie ty of loads and loading conditions. At 40 pounds per cubic yard or more, a good midrange or high-range water reducer (the latter at a low dosage) can be very helpful and is necessary as fiber dosages increase. Concrete Slab on Grade Stair Concrete Slab on Grade Stair RFreund (Structural) (OP) 27 Jun 14 13:53. compressive strength. 1-4. )(100)/(6 in.) 0. Basic considerations. Fire test of concrete slab reinforced with epoxy-coated bars. Reinforcement ratio can be defined as the ratio of reinforcement area to gross concrete area based on the total depth of the slab. The following slab reinforcement arrangements are specified in the BS 8110 Part 01. Many opinions have been voiced regarding the best vertical location for a single layer of reinforcing for slabs on ground. The reason for this is that the reinforcing cannot begin to start resisting significant tension until the concrete cracks. Slab On Grade Rebar Details. Demonstrate enlarged details at corners, junctions of walls, beams and column joint and at same situations. Grade Level Footing Drain Min Clearance Per Sections . Concrete floor slabs on grade are subjected to a variety of loads and loading conditions. In simply supported beams the main bars placed at bottom and in case of cantilever beam these bars are placed at top. In either case when using deformed bars or welded wire fabric, it is essential Reinforcement detailing of a slab is done based on its support conditions. However, if the cracks become wide enough to spall, this can be major problem. Reinforcement amounts much less than 0.10% have not provided dependable load transfer; and much more than this has caused excessive out-of-joint cracking. This deformed reinforcement is an alternative to smooth steel dowels, and slab expert Eldon Tipping has coined the term “long dowels” for this concept. Slab reinforcement details are the same as the wall reinforcements as specified in the Cl 3.9.4.19 in the BS 8110. Building guidelines drawings section b: concrete construction anchor reinforcement for podium slabs simpson strong tie structural engineering blog structure magazine recommended details reinforced slab on grade stud wall thickened edge walls. Thus, as with other types of reinforcing, the fiber dosage must be carefully considered with regards to the particular situation. A reinforced slab on grade will span soft spots by providing enough structural ca-pacity to bridge the weaker sup-porting areas. Tension anchorage lengths and additional reinforcement bars at the restrain edge are indicated in the following details. Words: 2,469; Pages: 4; Preview; Full text; CRSI REINFORCING STEEL IN SLABS-ON-GRADE ENGINEERING DATA REPORT NUMBER 37 A SERVICE OF THE CONCRETE REINFORCING STEEL INSTITUTE 933 N. Plum Grove Rd., Schaumburg, Illinois 60173-4758 WELDED WIRE FADRIC REINFORCING BARS INTRODUCTION The phrase slab-on-grade… In some situations, it is desirable to eliminate contraction joints in large placements and use enough reinforcing to have many, very tight cracks that do not spall under wheel traffic and are not an aesthetic issue; a common example is a true “superflat” slab strip placement. k. Reinforced slab. As indicated above, spacings for laps shall be followed and the gap between the lapping bars shall not be less than 50mm or 4∅ whichever lesser. Publication: Journal Proceedings Date: 12/1/1978 Grade 80 Reinforcing Bars and ACI 318-71 slab on grade reinforcement slab on grade reinforcement details slab on grade reinforcement calculator slab on grade … In general, there are similar requirements for one-way, and two ways slab when slab reinforcement detail drawings are prepared. If steel fibers are to be used for long-term enhanced aggregate interlock and the joint spacing is to be from 10 to 15 feet, the minimum amount of fiber considered for concrete with typical shrinkage properties is 40 pounds per cubic yard. Thus, unless the reinforcing is being used for other purposes (such as the “long dowel/enhanced aggregate interlock” concept noted later in this article), it is typically somewhat expensive insurance for a cracking problem that may never occur if other appropriate procedures are followed, such as proper joint spacing, dowels at joints, consistent slab thickness tolerance control, good base control, and low shrinkage mix design. Download & View Slab On Grade Reinforcement as PDF for free. This can reduce the required depth of the slab in colder climates. Structural loads, structural analysis and structural design are simply explained with the worked example for easiness of understanding. 0. This is due to being able to drive the concrete trucks and laser screed over them as they lay on the base and then chairing them up just ahead of the concrete placement, as the workers stand between the bars. Slab supported directly by columns are called flat slab. For 0.10% reinforcing, the slab joint spacing should be the same as for an un-reinforced slab. 2) Ask your contractor to protect topsoil for future use. #3 reinforcing bars at 16 or 18 inches on center are the most common reinforcing schemes used on slabs constructed with a laser screed. If reinforcing is utilized, the amount that should be used depends on what is to be accomplished. Restrain curling.Reinforcing the up-per half of a slab on grade restrains drying shrinkage, thus reducing curling. The simplified rules can be applied when slab reinforcement detail drawings are prepared when the following condition is met. THE SLAB DESIGN 10 BEAM SPACING AND LOCATION 12 SLAB REINFORCING 13 BEAM REINFORCING 13 SITE PREPARATION 14 SLAB FORMING 15 STEEL PLACEMENT 16 SPECIAL CONDITIONS 19 CONCRETE PLACING 20 ... grade before construction. 1.3.3 Columns—Column designs shall show the size of col-umns, number, locations, grade, and size of reinforcing steel, and all necessary details where column section or reinforce-ment changes. Provide 0.25% of the concrete crossectional area for Grade 460 steel. In this research, optimum design of reinforced cement concrete (RCC) ribbed slab, also known as waffle slab according to the Indian RCC code (IS 456:2000) is presented. slab: 4” minimum thickness with w or d9 wire 10” o.c. 24.Kas.2016 - Waffle Slab End Support Reinforcement Detail. analysis indicate a slab of lighter or heavier design is suitable. The rigid insulation is placed vertically on the exterior face of the grade beam. 29. Slab On Grade Reinforcement Details. Slab curling produces a significant tension stress in the top of all normal concrete slabs; if cracks do occur they are V-shaped with the widest portion at the top of the slab. Locating the reinforcement in the upper part of the slab is best when trying to control the visible crack widths due to the loading, curling, and base friction. Main straight bars: These bars are placed in tension zone. Some think it should be in the lower portion of the slab due to tension in the bottom of the slab when concentrated loads were to be applied. The chances for plastic settlement cracks increase as one or more of the following occurs: reinforcing diameter increases, concrete cover decreases, reinforcing temperature increases typically from sunlight, concrete bleed rate increases, reinforcing movement while the concrete is still plastic, or anything that increases moisture evaporation rate from the slab surface, such as higher concrete or ambient temperatures, higher wind speed, or lower humidity. Method of splicing shall always be defined The closer the steel is to the top of the slab and the more steel used, the more curling will be reduced. Publication: Concrete International Date: 8/1/2020 SP-339-06: Analysis and Design of Reinforced Cast-in-Place Concrete Diaphragms k. Reinforced slab. SLABS ON GRADE – IDENTIFYING THE PROBLEM Slab-on-ground is a well-used building solution in North America and other parts of the world, and they are very well known to not provide healthy interior environments. Practice oriented papers and articles ON REINFORCING SLAB ON GRADE Deflection of Flat-Plate Slabs. To have this kind of performance, sometimes called a “joint-less” floor, at least 0.50% to 0.60% reinforcing must be used near the top of the slab. Properly sized and located reinforcing will keep cracks reasonably tight and serviceable, if they occur, but will not prevent them. Min. (12 in.) Concrete is very strong when it is squeezed in compression but very weak when it is being pulled apart in tension. On the other hand, when […] But that was the old days when fiber 1st came out. Practice oriented papers and articles ON SLAB ON GRADE Deflection of Flat-Plate Slabs. concrete: 2500 psi min. As with steel bar or wire reinforcing, care must be taken if the joint spacing is extended beyond this specification. Let’s discussed the design code requirement specified for slab reinforcement details. Provide reinforcement area of 0.13%. Slab supported on two sides and bending takes place predominantly in one direction only is called One Way Slab. Wearing surface – the exposed surface of the floor, which typically receives some sort of surface treatment, be it a paint, sealant or a screed. Furthermore, the great majority of reinforced concrete designs that have been reviewed for slabs on ground do not have enough reinforcing to actually increase the slab's load-carrying capacity above that of an unreinforced slab. Thus, if there will be significant wheel traffic, consideration should be given to having a very good dowel system, such as plate dowels, at the construction joint and armoring the joint. Crack Control – when crack widths are not checked by calculations No Further Checked Required, Simplified Rule for Slab Reinforcement Details, Slab Reinforcement Details at Restrain Edges, Column Reinforcement Details [Must Check], Expansion Joints in Concrete [ why when how ], Typical Waterproofing Details in Buildings, The slab is designing for uniformly distributed loads, In continuous slabs, design loads are approximate equal. According to ACI Code 7.12.2.1, for the shrinkage and temperature reinforcement, Slabs with grade 40 or 50 deformed bars = 0.0020 psi. k. Reinforced slab. Mainly, there are three types of slabs in cast-in-situ concrete. 0. In some cases deformed bars are used in order to assure that the reinforcement is placed at the correct depth within the slab and not damaged during placement. maximum clear panel between beams is 15 feet.beams: 10” wide by 30” deep. This insulation aligns with rigid foam sheathing that covers the framed walls above grade. This type of slab is casted directly on ground level. Fig: Detailing of medium slab openings. A rectangular reinforced concrete slab is simply- supported on two masonry walls 250 mm thick and 3.75 m apart. 0. The design procedure includes determini ng slab thickness based The detailing rules could also be applied as per Eurocode 2. Minimum Reinforcement Ratio. 0. The slab on ground is in direct contact with the typical draining layer such as a gravel, sand or a compacted subbase and under complicated hydrothermal conditions. Generally, if one side is more than double of the other one, the slab will be one way. 1-4. Publication: Structural Journal Date: 3/1/1989 Pavements and Slabs on Grade with Structurally Active Reinforcement. If the desing ultimate shear stress at the face of the support is less than half the appropriate Vc, a straight length of bars beyond the centerline of the support equal to either one-third of the support width or 30mm, whichever is the greater. Concrete floor slabs on grade are subjected to a variety of loads and loading conditions. A good rule of thumb is that it is about 10 times as strong in compression as it is in direct tension. Provide 0.25% of the concrete crossectional area for Grade 460 steel. Not all reinforcement works the same way. Other considerations that play a role in the successful construction of a slab on grade include; proper proportioning of the concrete Slab curling produces a significant tension stress in the top of all normal concrete slabs; if cracks do occur they are V-shaped with the widest portion at the top of the slab. 0. Subslab insulation is placed horizontally, and extends down the sloped sides of the grade … Slab On Grade Rebar Details. Guidance for joint spacing to minimize out-of-joint cracking for such slabs is given in ACI 360 and typically should be in the 10- to 15-foot range noted earlier. As with steel bar and wire reinforcement, steel fibers will not prevent cracks but can keep cracks, if they occur, reasonably tight if a sufficient amount of fiber and an appropriate joint spacing are used. 1. both ways. Figure 4-9 illustrates a slab-on-grade foundation with an integral grade beam. JOURNAL Articles ON SLAB ON GRADE An Approximate Model to Predict Stress and Displacement of Cross-Tensioned Prestressed Concrete Pavement under Temperature Loading. Up next . (24” deep for attached garage. 146. These cracks will be visible, thus the aesthetics of these cracks should be discussed with the owner. One way Slab is a slab in which one side is very large compared to the other one. The design of a slab-on-grade includes all decisionsanddetailsmadebeforethejobisbidand constructed. The grade of steel should be evidently mentioned in the drawing. Element designs with notes and discussions have added to get comprehensive knowledge. Reinforcement detail for a waffle slab support on a reinforced concrete main frame end slab beam. Numbering shall start at D1 The location of reinforcing bars in relation to each other, particularly in connection details such as column to headstock, pile to pilecap and footing to column, should be closely examined to ensure that bars may be easily placed and that concrete compaction in that area can be achieved. Grade slab itself acts as a foundation for the building which does not require further footings. One thought on “ Concrete Slab-on-grade Reinforcement ” Dan Lindberg January 15, 2021 at 10:42 am. 2K Shares . More details. reinforced concrete slabs-on-ground, and slabs-on-ground in refrigerated buildings, followed by information on shrinkage and curling problems.