Design of Reinforced Concrete Slabs 107 B = 1.2x 1 where x = distance of load-from support closest to load I = effective span. Design of One-way Slabs: 1. The system requires zero propping, reducing construction time and labour costs. varies from 0.8 for narrow webbed O for rectangular sections. Contact Us | Traditionally column spacings and floor spans in these buildings have been in the range of 6 to 9 metres, to both contain costs and simplify construction. Fix assembly to one side of the truss, purlin or concrete slab with appropriate fixings (as in Figures 1 & 2) and at required centres (see span tables, page 31). Privacy Policy | For end spans and corner bays the ratios should be reduced by 10%. ‘Span/depth ratios for concrete beams and slabs’. Hollowcore Load Span Table. Using metal deck as forms for cement slabs over garages is a great alternative to building forms with wood and/or scaffolds. Flat slab design should be based on the longer panel dimension. Wide slab flooring is a high quality, economical suspended concrete floor construction using long prestressed concrete floor slabs (or planks) supported by either masonry walls or a supporting frame structure in steel or precast concrete. Efficient concrete cross section using up to 20% less concrete than other decks. The precast concrete Load Span tables provided below are to be used as a guide only. DESIGN OF SLAB: W= total design load per unit area. They have been calculated in accordance with BS8110. A quick and easier way to build suspended slab is to use metal deck if it’s accessible. For slabs spanning in both directions published tables and charts should be used to find bending moment and shear per unit width of slab. In situ concrete reinforced suspended floors can be designed to span one-way or two-ways between supports. Loads used in computations are 1.5kN/m2 Live Load and 2550 kg/m 3 DL( Wet concrete and self weight of sheeting and reinforcement) 3. Load Calculation: It is made of concrete and reinforcements are provided to support it. Longest unshored spans Excellent alternate to SDI DR (deep rib) profile Lower composite deck-slab weight than 3WxH-36 for the specified concrete thickness 8 inch on center low flute spacing to allow for bearing wall studs to be at 16 inches on center Non-composite deck 7⁄ 8 inch depth, 32 inch coverage 2 foot to 7 foot Span Range The calculated ratios are based on a service tensile stress fs of 500/(1.45x1.15) = 300N/mm². A large suspended slab deck was also added (see pics). Here primary beams are taken and secondary beams are not included in order to make the calculations short. The calculated ratios are based on a service tensile stress, 10. What are the potential problems in corners for concrete pavement? 4. 7. For the technical background to these recommendations see paper ‘Span/depth ratios for concrete beams and slabs’. There are two types of slabs – one-way slab and two-way slab. For end spans and corner bays the ratios should be reduced by 10%. As others have stated, as slabs increase in span they generally need to get thicker in order to develop the lever-arm needed to resist increased bending moment (simply put). These tables include: concrete compressive strengths of 25MPa, 32MPa and 40MPa; base metal thicknesses of the Condeck HP of 0.75mm, 0.90mm and 1.00mm; estimated maximum deflection of rib under wet concrete = span/240; density of concrete (plus allowance for steel reinforcement) = 2500kg/m 3; total slab deflection of Span/250, and This approach to concrete slab construction is very common in commercial construction. Also, the longer to shorter span ratio is less than 2 in all panel slabs so all slabs panels are two-way slabs. Disclaimer | If the structure did not require to be RC, I'd likely use structural steel as my first choice. Acoustic robust solution. (BS8110 Table 3.10 incorrectly assumes a service stress of 333N/mm² for 500N/mm² reinforcement.). 6. When these materials are mixed together, they form a workable paste which then gradually hardens over time. 9. For slabs over 10m, ratios should be reduced by the factor √(10/span in metres). Wood species is variable as well. A rectangular reinforced concrete slab is simply-supported on two masonry walls 250 mm thick and 3.75 m apart. 3. in Table 10.1.4(4) flanged beams to I. a simply- supported member an exterior span of a continuous member an interior span of a continuous member a cantilever. Simple online calculator to find the maximum slab length of a concrete floor by knowing the values of thickness of reinforced slab, yield strength, the reinforcing ratio. Cantilevers over 4m should be justified by calculation. The suspended … I need to minimize the thickness and width of the aprons. Values for intermediate stresses may be interpolated. In which direction should the main weight of reinforcement be placed in concrete pavement? Two-way slabs carry load in two directions and so reinforcements are provided in both directions. The lateral loads are independently resisted by shear walls. A simple cantilever span is formed by two cantilever arms extending from opposite sides of an obstacle to be crossed, meeting at the center. For slab loadings and layouts not covered, refer to BS8110. Guidance Diagram 10: Typical section through a suspended reinforced in-situ concrete ground floor slab supported on internal walls. Cut Suspension Rod to length. My = αyWly2. Considering M20 grade of concrete and Fe 500 steel of diameter of 10 mm It is estimated that a concrete slab lasts for about 30 to 100 years if it is built with good grade of concrete and steel. Calculate concrete slab maximum length . αx, αyare moment coefficients, 2. In one way slab the ratio of longer to smaller span is greater than or equal to 2 while in two-way slab the ratio of longer to smaller span is less than 2. Largely because of fast on-site construction, Bison hollowcore floors are one of the most economic flooring solutions for the widest variety of situations including masonry, steel and concrete structures for retail, commercial and industrial buildings. Tables are for formwork only. A reliable interlocking mechanism provides vertical lapping for faster installation. aprons? Suspended Slab on Metal Deck. Table derived from: vRd,c = 0.12 k (100 ρI fck)(1/3) ≥ 0.035 k1.5 f ck 0.5 where k = 1 + √(200/d) ≤ 2 and ρ I = As/( bd) ≤ 0.02 Note: This table has been prepared for fck = 30. The materials to be used are grade C25 concrete and grade 500 reinforcement. For the technical background to these recommendations see paper. 5.1.17 Ground floor slab and concrete Ground-bearing floors shall be of adequate strength and durability, and use concrete mixed and reinforced as necessary to … BONDEK® steel deck has a durable galvanised coating. The Suspended Concrete Floor meets Australian and NZ composite structural standards and the NZ Building Code standards for fire and acoustic performance. Usually for residential purpose M20 is used. 2. BS8110 provides a table for span to depth ratio which is based one total unfactored dead and imposed load. Thickness/Mass Stramit Condeck HP® decking is generally offered in three standard base metal thicknesses of 0.75mm, 0.90mm and 1.0mm.Other thicknesses may be supplied,dependent on lead times and availability. For instance, for 5KN/m^2 imposed on simply supported slab , D/L =29, 10KN/m^2, D/L=25, and 20KN/m^2, D/L=22. They have been calculated in accordance with BS8110. For the loading pattern to obtain maximum positive moment in a span of a continuous beam, why should alternative spans on each side of the span be loaded? Alternatively, the slab soffit can be formed with special moulds to give an … Please send any questions to estimating@milbank.co.uk or alternatively call us on 01787 223 931. 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. Slabs can be 90mm to 220mm in thickness. Ratios for continuous slabs are for internal bays. Attach Direct Fixing Clip (534 or 547) to one end and TCR clip 2534 to the other. Why is the span length ratio of end span/approach span to its neighboring inner spans usually about 0.75? A flat plate system will be considered first to illustrate the impact longer spans and heavier applied loads. Floor Finish = 1 kN/m2 DESIGN OF SLAB: Design of typical Floor Slab: We have thickness of slab as 130 mm. We have thickness of slab as 130 mm. Whereas in one-way slab the reinforcement is provided in one direction as it carries load in one direction. Mx = αxWlx2 In the pics you can see a Besser block pillar in … The spans … flanged beams and is similar to the multipliers recommended of AS 1480-1974 (10). If challenged for a solution that required reinforced concrete (RC), I'd likely have a column in the four corners and one (if allowed, at mid span of the long dimension) and likely break the 25m surface into 4 panels and treat it as a 2-way slab or maybe even use a 'waffle slab'. Two-way slabs have been calculated for a square panel. Free Civil Engineering Magazines and White Papers, Civil Engineering Notes From Universities, Geotechnical Investigation of a Construction Site, Explain briefly various types of Estimates, Design Calculation of an Isolated Footing, Types of Contracts in Construction Management, Factors Affecting Strength And Workability Of Concrete, Area of steel for maximum mid span moment (mm. Effective Depth: (130-15-10/2) = 110 mm. Here, in this problem first a plan of the house is shown then the slab panels are depicted as per the house plan. Detail 21 shows a suspended slab with no beam. In incremental launching method of bridge construction, what are the measures adopted to enhance sufficient resistance of the superstructure during the launching process? According to IS 456:2000 Clause D-1.1, maximum bending moment per unit width in the slab is given by- I am building a four post workbench type caster table with a 65" span. Tables are given showing the maximum allowable span between temporary supports (formwork). The design method is followed as per Annexure D of IS 456:2000. 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 … Copyright Policy | The design method is followed as per Annexure D of IS 456:2000. Minimum compressive strength of 25 mPa to achieve composite action is normally achieved within the first 72 hours of curing, depending on environmental conditions. For ribbed slabs, the ratio should be reduced by 20% (5kN/m²), 10% (10kN/m²), 5% (20kN/m²), where the quoted loads refer to total unfactored dead and imposed load. A slab is a structural element that is used to support ceilings and floors. Recommendations for the permissible stress design of reinforced concrete building structures. 1.0m cover width for rapid lay of deck on site. The tabulated ratios are for solid slabs designed to full stress using high yield steel (fy = 500N/mm²). The slab has to carry a distributed permanent action of 1.0 kN/m2 (excluding slab self-weight) and a variable action of 3.0 kN/m2. BONDEK® steel decking permits installation of suspended services and ceilings without drilling into the concrete slab. Testimonials. For ribbed slabs, the ratio should be reduced by 20% (5kN/m²), 10% (10kN/m²), 5% (20kN/m²), where the quoted loads refer to total unfactored dead and imposed load. Greater … Also, the longer to shorter span ratio is less than 2 in all panel slabs so all slabs panels are two-way slabs. Where lx and ly are the length of the shorter and longer span respectively, The plan used for gravity analysis of a building is similar to slab panels also. Alasdair’s Engineering Pages © A. N. Beal 2019              www.anbeal.co.uk, Span/depth ratios for reinforced concrete slab design to BS8110. Ratios for continuous slabs are for internal bays. Aluma Frame Table; Aluma Alumacs; Alumalite Truss; Aluma Hi-Load; Aluma Hi-Flyer ; Aluma Beam / J-400; TOPMAX; ProDeck; Aluma Garage Beam; Custom Garage Beam; Shoring; Monolithic Formwork; Climbing Formwork; Ties & Accessories; Access Scaffold; Custom Steel Applications; Site and Safety Products; Formwork & Shoring; Slab Formwork; Aluma Beam / J-400; Aluma Beam & J-400. 10. 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. Total = 6.25 kN/m2, Determination of Moments of slabs (Laterally Restrained slab): My question relates to a suspended slab at the rear of my property and the length the channel beams around the edge of the slab can span between posts. Concrete Slab Maximum Length Calculator. You can list yourself here by submitting civil engineering related topics to us. Two-way slabs are supported on four sides while one-way slabs are supported on two opposite sides. 6.0 Design tables - steel-framed construction 19 6.1 Use of design tables 19 6.2 Interpretation of table solutions 20 6.3 Single span tables 21 6.4 Interior span tables 23 6.5 End span tables 28 7.0 Construction and detailing 33 7.1 Safety33 7.2 Care and storage before installation 33 7.3 Installation of BONDEK® sheeting on-site 33 A finite element model may be created to analyse a complicated loading arrangement. 8. Such floors can be designed and constructed to have a continuously flat soffit. The Speedfloor building system is a light-weight suspended concrete floor solution, that uses a cold formed steel joist as an integral part of the final concrete and steel composite floor. Concrete is a composite material, consisting mainly of Portland cement, water and aggregate (gravel, sand or rock). Spans up to 4.5m unpropped. INTRODUCTION Mx and My are moments on strips of unit width spanning lx and ly respectively, suspended floor slab applications and strictly as shown in this and other current Stramit technical literature. Live Load = 2 kN/m2 Hollowcore Floors Load/Span Table. 4. 1. Hence Safe, About Us | 5. 5. Fire performance up to 4 hours. Two-Way Joist Concrete Slab Floor (Waffle Slab) System Analysis and Design Design the concrete floor slab system shown below for an intermediate floor with partition weight of 50 psf, and unfactored live load of 100 psf. Here the highest moment is taken from the table below. Design of typical Floor Slab: 590mm cover 200mm 54mm DESIGN ADVANTAGES INCLUDE: • Excellent spanning capacities for greater strength and less deflection • Acts … Is there an online calculator that will give me a load span maximum for 1x4x65" vs. 1.25x4x65 etc. Self-weight of the slab = 3.25 kN/m2 For a 2x1 panel, the value for a one-way panel should be used and values interpolated for intermediate proportions. In a common variant, the suspended span, the cantilever arms do not meet in the center; instead, they support a central truss bridge which rests on the ends of the cantilever arms. Structural Standards. 5. The table is given as a guide only. However, recently there is a preference for large floor areas with column-free space and spans. … Looking for a quotation? Can the use of temporary nose in incremental launching method reduce the cantilever moment of superstructure to the value of inner support moment? The house was Originally a single story weatherboard dwelling before being raised in 1993 and clad with double cavity brick. Concrete floor - Designing Buildings Wiki - Share your construction industry knowledge. Intermediate values may be interpolated. Please Contact Us for specific information regarding your project. Determine the required thickness for deflection control in the slab from the table below: Minimum One-way Slab Thickness (unless deflections are calculated) (Normal Weight Concrete, fy = 60,000 psi (413.7 MPa)) Guidance Table 5: Examples of insulation for ground bearing floor slabs Suspended reinforced in-situ concrete ground floor slab supported on internal walls. of stuff. It is several inches thick and it rests on beams and columns. 1 hour fire performance with 130mm slab depth. For a steel service stress of 150N/mm² the quoted ratios may be increased by 20%. The IStructE ‘Gold Book’ Recommendations for the permissible stress design of reinforced concrete building structures provides an alternative design guide for reinforced concrete guidance which is easier to use than BS8110 but has been fully updated in line with the latest edition and produces similar results. Home designers sometimes use suspended patio slab that is attached to the main structure to serve as floor for a front porch or canopy while the bottom can be extra storage or bunker for protection from hurricanes and tornados. Considering M20 grade of concrete and Fe 500 steel of diameter of 10 mm 4. The top will be 2" concrete and lower shelf will be holding 400lbs. The tabulated ratios are for solid slabs designed to full stress using high yield steel (, 1. Our dedicated sales and estimating team are on hand to answer any of your queries. Media | Do not use for any other purpose. Gauge range 0.9mm through 1.2mm for economic solutions. 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