Pdf comparison between ribbed slab structure using. They provide a very good form of construction where slab vibration is an issue, such as laboratories and hospitals. Ribbed slabs are made up of wide band beams running between columns with narrow ribs spanning the. What is the difference between a flat slab and a ribbed slab. The rib reinforcement follows the same rules with the beam reinforcement. Ribbed slab system which consists of a series of parallel reinforced concrete t beams framing into reinforced concrete girders. In reality, sandwich slabs are ribbed slabs with a slab placed both to their upper and lower surface. Teaching twoway ribbed slab analysis and design using the. However, mainly as far as the stirrups are concerned, the amount of placed rebars is not as large as it is in beams. Ribbed slab design spreadsheets to eurocode engineering books. Ribbed or waffle slab is a slab system which consists of series of parallel reinforced concrete t beams framing into reinforced concrete girders. They may be solid of uniform thickness or ribbed with ribs running in one direction or two directions waffles. Waffle slab is good against shrinkage and it is lower than stiffened rafts and footing slabs. This form of construction is not very common because of the formwork costs and the low fire rating.
Concrete slab types construction, cost, and applications. In waffle slab design where the drop panels create a large critical shear perimeter, the factor b o d has limited contribution and is traditionally neglected for simplicity and conservatism. Hollowcore ribbed slabs derive their name from the voids or cores which run through the units. This answer will be easy if i make you understand with a building structure. In reality, sandwich slabs are ribbed slabs with a slab. Sandwich slab reinforcement details in reality, sandwich slabs are ribbed slabs with a slab placed both to their upper and lower surface. Dec 06, 2017 basic of ribbed slab with aci 31802 code requirements. Additional reinforced internal ribs are then used in the slab by introducing pontex, the structural cupolex accessory to provide a structure capable of spanning between foundations or piles. Slabs are structural members forming floors and roofs in buildings. Ce tcc ribbed slab rei60 01 bruninghoffgruppe free bim. Ribbed slabs oneway joists introducing voids to the soffit of a slab reduces dead weight and increases the efficiency of the concrete section. The saving of materials tends to be offset by some. Because of the ribs and double reinforcement, it is more stable and recommended for larger span slabs or foundations. The model provides the actual behavior for ribbed slab by analyzing the structure as oneunite in two dimensions.
The ribs are tapered in crosssection in its lower part. Twoway joist waffle slab design approach and methodology. The ribbed slab was analyzed exactly by finite element theory through sap 2000 program. Concrete rib construction method, crcm uses the engineering technology to design the elements structurals to handle the loads originated by climatic and or geographical location of the project. Structural ribbed concrete slabs cupolex sustainable. Ribbed slab a panel composed of a thin slab reinforced by ribs in one or two directions, usually at right angles to one an other. Waffle slabs contain a skinny topping slab and thin ribs across both directions among column heads or band beams. The main advantage of the ribbed floor is the reduction of the quantity of concrete and hence the considerable savings in the cost.
Ribbed slabs types and its advantages in construction purpose. Which slab is better ribbed slab or solid slab one way or. The cost is managed by supervision of non skilled laborers, following the recommendations in this manual. Aug 09, 2014 ribbed floors consisting of equally spaced ribs are usually supported directly by columns. Pdf ribbed slabs have been widely used in buildings due to their many. Ribbed and waffle slabs types, advantages, disadvantages. Ribbed expanded metal sheets can be placed with the ribs positioned horizontally or vertically. Sir pdf for manual calculation so it will be easier to carry on in software. Ribbed expanded metal serves as bulkhead form concrete. The construction of waffle slabs can be done by three ways as follows.
Additional reinforced internal ribs are then used in the slab by introducing pontex, the structural. This paper presents an experimental and computational. Slabs are usually used in floor and roof construction. Waffle slab or ribbed slab construction procedure and advantages. Steelreinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ceilings, while thinner mud slabs may be used for exterior paving see below. Investigation on the suitability of pumice and scoria. The ribs are categorized as ribbed slab and waffle slab.
Comparison between ribbed slab structure using lightweight foam concrete and solid slab structure using normal concrete. This document provides guidance for the design and construction of conventionally reinforced ribbed mat slab rrms foundation systems. See more ideas about waffle ceiling, architecture and ceiling design. This 300 mm deep ribbed slab is required for an office to support a variable action of 5 kn m2 it is supported on wide beams that are the same depth as the slab, as shown in figure 3. The code recommends that the ribs should have a width bw not greater than 100 mm. The cupolexpontex technology is at the forefront of conventional concrete slab construction.
Waffle slab requires only 70% of concrete and 80 % of steel from the concrete and steel used for stiffened raft. First of all, it depends on the use of the structure. The cores can function as service ducts and significantly reduce the selfweight of the slabs, maximizing structural efficiency. Cupolex accessory to provide a structure capable of. Applications include commercial, industrial and residential buildings. The top of ribbed slab is normally thin and the bottom grid lines are generally ribs which are laid perpendicular to each other with equal depth. Check the applicable joist dimensional limitations as follows. This is attributed to the rapid shattering, ease of construction, and the reduction in the time of erection. Twoway joist concrete slab floor waffle slab system.
Jul 02, 2015 for the love of physics walter lewin may 16, 2011 duration. A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Due to the high formwork cost and degraded fire rating, this type of construction generally is not recommended. Ribbed slabs are constructed with wide band beams which run through amid columns having equal depth narrow ribs across the orthogonal direction. When used to form bulkheads in 10 to 20footdeep foundation mats, the sheets are generally placed with the ribs horizontal so that the bracing can be oriented vertically. Composite construction has proven popular because it combines structural efficiency with speed of construction to offer an economic solution for a wide range of building types. Ribbed slabs types and its advantages in construction.
Between the ribs, the slab is usually reinforced with a common wire mesh. This is a very efficient form of slab construction, it is also called a hollow block voided slab or pan joist system. This guide covers the design and construction of composite slabs and beams, and. Considering a building structure structurally we generally found the following components 1. Ribbed slab article about ribbed slab by the free dictionary. In ribbed slab, there is oneway spanning and in a waffle slab, there is twoway ribbed system. According to the way loads are transferred to supporting beams and columns, slabs are classified into two types. Ribbed and waffle slabs provide a lighter and stiffer slab than an equivalent flat slab, reducing the extent of foundations. Investigation on the suitability of pumice and scoria aggregates in ribbed slab construction. Abstract this paper presents the use of ethiopian pumice and scoria aggregates for lightweight concrete in ribbed slab construction.
Comparison between ribbed slab structure using lightweight foam concrete and solid slab structure using normal concrete article pdf available march 2010 with 5,246 reads how we measure reads. They are either oneway spanning systems known as ribbed slab or a twoway ribbed system known as a waffle slab. Shrinkage of slab is lower than stiffened rafts and footing slabs. Waffle slab or ribbed slab construction procedure and.
Aci 318 minimum slab thickness for twoway construction. Ribbed slab design spreadsheets to eurocode ribbed slabs are widely used in many countries. No beam down drag from clay above ground slab occurs. Ce tcc ribbed slab rei60 01 bruninghoffgruppe oggetti. The slab is the flange of the beam and the extended part is the web. Which slab is better ribbed slab or solid slab one way or two way. Waffle slab or ribbed slab is a structural component which is plain on its top and contains grid like system on its bottom surface. Continuous ribbed slabs concrete structures eurocode. In this example, the latter option will be used to achieve better understanding for the design of twoway joist slab often called twoway ribbed slab or waffle slab. The spacing between the ribs should be in general 2030 inch. Smearing the geometrical properties of a waffle ribbed slab, such as its second moment of area into an equivalent slab of uniform thickness might be an approximation acceptable for deflection analysis of conventionally reinforced concrete, but does not work for posttensioned floor systems.
Ribbed slabs have been widely used in buildings due to their many advantages, especially the decrease of concrete below the neutral line. Reinforced concrete ribbed slabs with widebeam lajes. Twoway joist concrete slab floor waffle slab system analysis and design. Introducing voids to the soffit of a slab reduces dead weight and increases the efficiency of the concrete. Structural ribbed concrete slabs the cupolex floor slab can be fully or partially suspended on piles, stem walls or gradeedge beams. A slightly deeper section is required but these stiffer floors facilitate longer spans and provision of holes. Sandwich slabs may have the disadvantage of a larger weight compared to the ribbed ones but on the other hand, they have the advantage that their spans and supports behave in the same proper way.
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