That would require calculating the failure point of a two inch slab of concrete, in bending, involving the psi strength of the concrete, and the aggregate size. A concrete slab is a structural feature, usually of constant thickness, that can be used as a floor or a roof. The load / span chart below clearly shows the maximum span for the required loading using either aerated, medium or high density infill blocks and 65mm screed. Waffle slab requires only 70% of concrete and 80 % of steel from the concrete and steel used for stiffened raft. Several factors like poor concrete quality, improper structural design, inappropriate steel bar spacing, large slab span, improper aggregates, etc. For years, post-tensioned concrete long-span slabs … Ron: If the pours are too long, then the construction joints between pours may open excessivly, when the concrete dries and shrinks; the sawcut control joints don't necessarily break open and accommodate the shrinkage movement, particularly if placed on a low friction surface (we have had this problem many yeras ago), so I think it is prudent to have a maximum length of pour. Where it forms end of a continuous slab, the length of centre of support shall be taken. Fixed slab The sagging moment at the mid-span is wl²/24 and hogging moment at support is wl²/12. This paper considers the span/depth rules proposed by Eurocode 2 [1] and compares them with existing UK practice. Typically, for a two-way slab, the loads are either triangular (for the beam parallel to the short span direction of the slab) or trapezoidal (for the beam parallel to the long span direction of the slab) as shown in Figure 5. For aesthetic purposes, you can use the ceiling slab bottom of the concrete slab. Span SITECAST CONCRETE SLAB BANDS 203 mm 152 mm The top chart is for sitecast con- crete one-way solid slab construc- tion, either conventionally rein- forced or posttensioned. concrete topping [1] significantly increases the attractiveness of this type of slab. l Easy to work with and adaptable to all wall systems l Two Hour Fire Rating – Best in the industry! For main bars, maximum spacing is restricted to 3 times effective depth or 300 mm whichever is smaller. For distribution bars, the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is smaller. Similarly, you may ask, what is the maximum length of cantilever slab? A concentrated load of 90,000 lbs in one square inch, or even a square foot, is much different than a distributed 90,000 lb load over 1000 square feet. For heavy loads, read toward the left. This research is intended to first application of lightweight concrete to construct large-span post-tensioned slab. Click to see full answer. Code gives the maximum limits of deflections base on the spans. RC4 – Two Span RC Concrete Slab Last Modified: 8/29/2016 3 To add a new concrete material, click on Concrete in the tree and select File/New from the menu (or right mouse click on Concrete and select New). (ii) For end span, with one end free and the other end continuous, the effective span shall be equal to clear span plus half the effective depth of slab or clear span plus half the width of discontinuous support whichever is less. A suspended slab (or structural slab) spans between supports and must be reinforced to resist bending moments calculated from statics based on the magnitude of load and span. * The span to depth ratio for a cantilever slab should not exceed 7. Similarly, it is asked, how much weight can a concrete floor hold? This slab design can only work for a slab clear span of 14 feet which is only good for one car garage, 2 cars if parked behind the other, not side by side. Completed slab mass and Site Concrete Quantity based on 3 metre x 9 metre pre-cast elements with 51 kg/m2 total reinforcement. For light to medium loads, read toward the right in the indicated areas. You can consider it as beam with breadth more than 1m directly resting on column. Likewise, how far can steel cantilever? The maximum shear force is at support, equal to wl/2 The maximum deflection is at mid-span, equal to wl⁴/ 3.84EI. Design process includes proper assumption of structural element sizes and then check […] The following table presents limits on slab span/effective depth ratio which can be used to work out the correct thickness for slabs directly at the start of design, without any need for later adjustments. Following either method, the maximum allowable deflection in concrete beams needs to be limited. Version Slab Thickness These tables are are provided as a guide only. The magnitude of load transferred depends on if the slab is spanning in one-way or two-way. The span to depth ratio for a cantilever slab should not exceed 7. Imposed loads varies from approximately 1.5 kN/m 2 (153 kg/m 2) in domestic buildings to approximately 10 kN/m 2 (1053 kg/m 2) in heavy industrial areas. Detail 21 shows a suspended slab with no beam. 500 kg/m 2 is typical for office, storage space and similar. The flat slab with large span is achieved in this way. There is nothing in ACI with that kind of language, though sanitary facilities have a spec calling for concrete to have complete joints every 30 feet (with water stops), but that may be a poor guideline too. While the issues pertaining to improper structural design can be eliminated in the design stage, the other factors can be avoided in the construction stage of […] 3. The deflection can be checked by two methods. With skewed spans, use shear keys that are 2 in. In reinforced concrete design, deflection is normally controlled by limiting the span/depth ratio of a beam or slab. are responsible for the development of cracks in RCC slabs. 150mm concrete beams are most commonly used in domestic house building projects, garages, extensions, conservatories etc. If you know the maximum deflection for the relevant load case, we can check whether it is with in the limit. Minimum thickness of concrete structural elements based on ACI 318-14, IRC 2009, IS 456 2000, and UBC 1997 is presented. The ratio of longer span (l) to shorter span (b) is equal or greater than 2, considered as One-way slab. 4 ComSlab® LONG SPAN CONCRETE FLOOR SYSTEM Com Slab® B EN FIT l Cost-effective l Unique benefits not found in pre-cast or cast-in-place reinforced concrete construction . The load/span tables show the maximum clear span for both domestic and other loading conditions, such as nursing homes, hotels and commercial developments. Deflection Control. Waffle slab is good against shrinkage and it is lower than stiffened rafts and footing slabs. The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. Minimum thickness of concrete slab, beam, column, foundation and other structural members is selected to meet the design requirements as per standard codes. 3. The precast concrete Load Span tables provided below are to be used as a guide only. Checking slab deflection is included in the beam design section of BS 8110 Part 01. 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