The lattice girders are used mainly as reinforcement of prefabricated slabs and beams, where concreting is performed in two stages, offering the advantage of avoiding scaffolding and formwork needed in traditional construction. Vt 20k the costeffective solid web girder gt 24 the versatile lattice girder with a high loadbearing capacity the peri vt 20k is the economical, 20 cm high solid web girder. The cobiax system of biaxial design in conjunction with the void forming sy. Typically, a change in the lattice girder design such as a different wire. Onsite experimental and numerical investigations of. Now an attempt has been made to gather information on the design principles from various references on the layout and other design principles. Analysis of the behaviour of hybrid concrete lattice girder slabs during. The girder slab system is easily integrated with lateral resisting steel braced frames and concrete or masonry shear walls. Steel roof trusses are used for mainly for the industrial buildings where. The karabiners are hooked into the diagonals of the truss lattice girder, not into the upper boom. Lattice girder elements investigation of structural. Lattice girder reinforced semiprecast slab and its insitu placement. Slab depth mm 115 125 150 175 200 225 250 300 350 400 1.
Possible dimensions are stated below or can be found in the product range. All omnia products incorporate the triangular omnia lattice girder that is attached to a. Newell and goggins 3 carried out experimental tests of lattice girder composite slabs at the construction stage and examined the key parameters that in. Onsite experimental and numerical investigations of latticed.
Construction of precast filigran slab at a glance structville. Beams and girders an overview sciencedirect topics. The lattice girder floor consists of preproduced, largeformat, reinforced concrete slabs, at least 5 cm thick. Feb 12, 2021 a lattice girder is a type of girder with a crisscrossed web design, such as in gardening lattices, between the two edges of the girder. Experimental and numerical study of lattice girder. The terms are generally applied to the planar truss. The units are typically 50mm to 100mm thick and 1200mm or 2400mm wide. Multiflex the flexible girder slab formwork for all ground. The system has been extensively tested and used successfully for numerous tunnel projects throughout the world. However as per my load coalculations, analysis and design results i needed 697 sqmm steel area, i provided 4 dia 16 mm rebar i. Ground treatment a critical issue in design of mitigation measures is avoiding the creation of hard points in the building that can focus and amplify building response or damage.
Highly effective lattice punching shear reinforcement filigran. Lattice girder elements chalmers publication library. Hollowcorefloors the core can function as service ducts reduce the self. Title publication behaviour of hybrid concrete lattice. The lower chord already contains the complete reinforcement for floor loads commonly found in residential buildings. Mar 29, 2021 thus, lattice girder composite slabs were developed. The statically significant made to measure mesh and the lattice girders have already been inserted in the factory. Lattice girder floor slabs tested application as a pointsupported slab. Standard lattice girders are available in stock in several dimensions. Original article proposition of a simplified analytical. Pdf laboratory testing of the structural behaviour of. Diaphragm action composite lattice girder floors can be designed to provide diaphragm action to transmit. Large or small holes, services in the topping, beams within the depth of the slab all easily achieved. Omnia and cobiax flooring systems hanson pdf catalogs.
Precast concrete lattice girder slabs consist of a. Lattice girders have been developed for special demands in the field of tunneling. Pdf lattice girder floor slabs tested application as a point. Specifications 3bar girders us customary units cp size h. Application and use of the information published by girder slab technologies. Precast concrete lattice girder flat slabs are designed and manufactured in accordance with european standards 1,2 but the importance of the various design parameters in precast lattice girder floor systems are not fully understood 3.
They are delivered as a lattice girder floor, installed on the construction site and filled with castinsitu concrete. Current turkish and european standards force engineers to design the bending ultimate. Performance of joints in reinforced concrete slabs for two. Therefore lattice girders are best suited when slab reinforcement is generally light, while at the same. In the erection state, the precast floor plates carry their own weight, the load. Therefore lattice girders are best suited when slab reinforcement is generally light, while at the same time fast and noformwork construction is needed. Design, manufacture and construction of buildings with. When the order is placed, the lattice girder height h, lower chord diameter lc, upper chord size uc and diameter of diagonals d are specified. Comparison study for various structural slab systems table of contents 1. The lattice girder according to the present invention comprises two base joists and a top. Many books are course oriented and not with a practical principles.
All reinforcement used in manufacturing uses multicycled steel. Analysis of the behaviour of hybrid concrete lattice girder slabs. The girder slab system is available for use by industry professionals. Lattice girder types with different rebar diameters and dimensions, hence equivalent design values e. Precast half slabs with lattice girders by wbkengineers. Contrary to standard solidweb girders, lattice girders are entirely integrated in. Stabilizing suspension gear should be used while lifting the filigran slab. Girder slabs are now part of the precast automation process, following similar configuration r. The approved increase factor based on the german design standard. The electrowelded lattice girders manufactured by the pittini group, which are well known all over europe owing to their range, high quality and expert technical support, are used to make floor lattice girder beams for claycement mix or concrete floors, lattice girder slabs bridge decks, large monolithic or lightened floors and double. The lattice girder provides rigidity to the slab when insitu concrete is poured onsite by a local provider. Grouted canopy spiling and lattice girder rigid support of excavation systems secant pile walls, etc. The slab weighs approximately 125kgm2 standard thickness.
You can also choose from traditional, contemporary, and industrial lattice girder design, as well as from 1 year, 2 years, and more than 5 years lattice girder design, and whether lattice girder design is nonalloy. Experimental tests, precast concrete, lattice girder slabs, hybrid concrete. The practical design of truss members is discussed. Precast floor plates for floor systems consist of precast reinforcedconcrete slabs of 5 cm thickness in which lattice girders are incorporated fig. Sustainability free fulltext onsite experimental and. The girder slab composite steel and precast system breaks new ground for multistory residential building superstructures. They are used in conjunction with shotcrete and act as armor to achieve a good level of support in tunneling. Clause cover to rebar, c 30 mm normal weight concrete 3. This paper describes the methods that can be used to optimize the design of tunnels using a combination of reinforcement and support methods.
Lattice girder composite floor systems precast flooring federation. The lattice girder slab consists of a thin precast. They are cast with most, if not all, of the bottom reinforcement required. Lattice girders ensure an immediate support in the open span area. A wide variety of lattice girder slab options are available to you, such as project solution capability, warranty, and aftersale service. The gt 24 formwork girder the versatile lattice girder with a high loadbearing capacity the gt 24 formwork girder provides a high loadbearing capacity and rigidity. Support panels on the formwork and cast a fully homogeneous slab. This includes the criteria and the allowable stresses used in the design, as well as alternative types of girder with advantages and disadvantages given for each. The 2008 kersten lecture integration of geotechnical and. Omnia slab is a reinforced precast concrete slab incorporating a triangular. Lattice girder elements, pilot experiment, bending, design and analysis method. Filigran slabs are generally unloaded from the truck by a building site crane. Design composite floors using lattice girder planks are designed in accordance with the relevant sections of eurocode 2.
In the existing design manual propping requirements are calculate with empirical. The structural design of flat slab systems is usually governed by the punching shear. Pdf comparison study for various structural slab systems. However, if cracking is allowed the crack width in the finished slab must.
Gt 24 formwork girder the versatile lattice girder with a. Increase of punching shear resistance of flat slabs or footings and ground slabs lattice girders calculation methods jan 1992 en 199211. The truss or lattice girder is a triangulated framework of members where loads in the plane of the truss or girder are resisted by axial forces in the individual members. Fdb ii a new generation of punching shear reinforcement. The supporting bearer beams of the temporary falsework support system require to run in parallel rows, typically not more than 2000mm apart and at right angles to the lattice girders in. The comparative results of computer analysis are discussed in chapter 7 to further clarify the advantages and distadvantages. Mar 29, 2021 it is emphasized that the design parameters, such as size, thickness, and reinforcement of the slab, strictly followed the code for design of concrete structures gb5001020102015 and the technical specification for application of lattice girder slab tcecs 7152020. On the basis of experimental examinations, the loadbearing behavior and dimensioning concept of lattice girder floor slabs as a pointsupported slab is illustrated. One such method is the use of precast concrete lattice girder slabs, or filigree slabs, as an alternative to insitu flat slab construction. Pdf realtime monitoring of concretelatticegirder slabs during. Part 3 design and detailing ezekiel enterprises, llc. The diagonal lines of steel give support in all directions, helping to prevent the girder, which is one of the main support elements in a bridge design, from bending. While putting up lattice girder by means of textile slings the following rules have to.
In the erection state, the precast floor plates carry their own weight, the load imposed by the insitu concrete topping and the live load. Design value of resistance kn of diagonal reinforcement against shear force. For the sake of this answer lets agree that a girder is what most people would call a beam. This included both smallscale specimens and fullscale assemblies in. Long erection spans with strengthened lattice girders. Wall 180 o 400 mm t double wall and lattice girder slab. The girder nodes with minidovetail jointing ensures the stability of the gt24 formwork girder through a special node design in the timber chord. Pdf structural engineering design of rc structure using. Soffit can be left exposed saving on additional costs for suspended ceilings. Aussteifungselement spinne x y s 1 b h e s 3 s 2 30 50 h 1 gurtstab s2 gurtstab s3 specifications 3bar girders 6. The majority of the floor structure is 400mm thick and is constructed using a twoway spanning hybrid precast concrete lattice girder flat slab system.
In order to develop a rational analysis that would maximize the use of the. What is the difference between plate girder and lattice. Diaphragm action composite lattice girder floors can be designed to provide diaphragm action to. Slabcolumn connection with effective lattice shear reinforcement.
Lattice girder slabs beam and block flooring double. Structural performance of precast concrete lattice girder. The results show that the structural behaviour of the lattice girder. Title publication behaviour of hybrid concrete lattice girder. Now another engineer at site is in a technical argument with me that, we cant provide 4 dia 16 bar in those columns and we need to provide 212 dia extra rebars in them i. The load increase factor relatively to slabs without punching shear reinforcement acc. Approved continuing education for licensed professional engineers design and construction of road tunnels. Flat slabs with fdb ii filigran punching shear reinforcement show an increased punching shear resistance in comparison with other punching shear systems, and they are resilient to. The omnia slab is a reinforced precast concrete slab which incorporates a lattice girder to provide stiffness and facilitate the placement of the top mesh. A lattice girder truss and a lattice girder element. Lattice girders with the complete reinforcement required for residential buildings are a special form of truss girder.
Key design factors 0 d suspended portal frame b frame with hinged column bases a frame with fixed column bases c frame with lattice girders b structure with purlins d cable suspended beams with purlins a structure without purlins, roof stiffened by trapezoidal sheeting c lattice girder with purlins figure 2. Design of precast concrete long clear span proven design and methodologies. Contractor remains responsible for the design of temporary works and lateral stability of the falsework system adopted in the temporary stage. European technical approval eta521 building component tests according to approved european guidelines form the basis of european technical approval eta521. Lattice girders are threedimensional, industrially prefabricated reinforcing elements. In crown heading excavation, for example, immediate support should be applied to the excavation with lattice girders. Lattice girder slabs act as permanent formwork and as precast soffits for robust, high capacity composite floor slabs.
A wide variety of lattice girder design options are available to you, such as graphic design, others, and 3d model design. Precast half slabs with lattice girders are composite slabs made of precast concrete planks of aroun d 50mm to 60mm thickness with a reinforced concrete topping. Integral lattice girder helps makes progressive collapse design easy. Loadbearing capacity and serviceability of precast slab when installed. The results are evaluated according to the american design rules of aci 31814. Through the use of the girder for wall, column, slab or special formwork, consequently both material quantities and workloads can be reduced. Experimental study of hybrid precast concrete lattice. Experimental study of hybrid precast concrete lattice girder floor at. Lattice girder slabs function a floor system that serves as an alternative to conventional concreteinplace floors, in which a prefabricated slab with reinforcement serves as a permanent formwork for the final casting of the floors. A plate girder is a beam that is made by welding 3 plates together to make an ibeam section. While putting up lattice girder by means of textile slings the following rules have to be obeyed.
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