Redevelop industrial buildings with innovative SFRC floors

2022-06-19 10:04:19 By : Ms. Ella liang

The redevelopment of two existing industrial buildings in Bobbio (PC) was an opportunity to verify the potential of a partially prefabricated fiber-reinforced concrete floor solution designed according to the 2010 Model Code. The article aims to describe and comment on the the most significant design and construction phases in order to highlight the main advantages, as well as the checks carried out to ensure the success of the final product.Fiber-reinforced concrete floors represent an interesting design solution guaranteeing structural strength, speed of execution, flexibility and cost-effectiveness when combined with traditional reinforcement placed only in some portions of them.The diffuse reinforcement, provided by the fibers, is valid at the same time to resist the bending, shear and punching action and a continuous reinforcement, provided by the traditional reinforcement, placed only in the critical areas where the propagation of the cracks followed by the localization requires greater flexural or shear strength to support the loads acting in service and at the ultimate limit state.The possibility of grading the reinforcement is one of the main advantages of reinforced concrete because it allows to make the most of the performance of the materials and to reduce the demand for ductility in order to reach the maximum load that can be calculated through the limit analysis.The article presents a partially prefabricated solution that aims to combine the advantages of prefabrication with those of a cast-in-situ structure.This solution was implemented in a recent industrial building based in Como and in the renovation of an industrial building in Bobbio.The proposal replaces the classic TT tiles with prefabricated prefabricated fiber-reinforced beams of 8.80 ÷ 14 m of span and thin predalles-type slabs, also in fiber-reinforced, which rest on the upper current of the prefabricated beams.It is thus possible to adapt the spacing between the beams, remaining self-supporting, reducing the transport costs of the solution without compromising the speed of execution.The solution is completed with a final layer of fiber-reinforced concrete, capable of guaranteeing bidirectional behavior to the floor not only from a membrane point of view, but also from a flexural point of view, being able to exploit the structural redundancy of a ribbed plate solution in only one direction.The memory focuses on the solution from the designer's point of view in order to highlight its innovative aspects.Description of the buildings Building A: current statusBuilding A, the subject of this first intervention, built in the 1980s, is characterized by a rectangular plan and a total area of ​​approximately 2800 m2.The building consists of 8 equal spans of 35 mx 10 m plan dimensions, with prefabricated isostatic pillars embedded at the base on which the double-slope reinforced concrete trusses with type W and Π roofing tiles rest.The redevelopment involves a single span of the entire complex, and includes the basement, the ground floor used as a warehouse and the first floor used as a residential building and offices.The floor covering the ground floor, made with prefabricated reinforced concrete slabs of the "Predalles" type, rests on a row of central reinforced concrete pillars, cast on site, which continue from the basement and are connected by an upper beam in reinforced concrete with a rectangular section , on load-bearing side walls, one in reinforced concrete and the other in brick, inserted between the prefabricated pillars.On the first floor, the roof slab that acts as a false ceiling is made of brick and rests on load-bearing brick walls.FIGURE 1: Current state of the portion of the industrial building object of the intervention (the parts to be demolished are highlighted in yellow): plan view of the first floor (a) and section (b).Project statusThe intervention involves the demolition of the floor covering the ground floor, the central pillars on the ground floor, the beam, the brick walls and planks on the ground floor and, on the first floor, the false ceiling covering on the first floor.The construction of a new deck is also planned, which will be used for industrial activity.The new SFRC floor - which will be discussed in detail in §2.3 - rests on one side on steel plates connected to the existing reinforced concrete wall, on the other on a new prefabricated structure consisting of prefabricated L-section beams resting on pillars with rectangular section.These pillars have variable dimensions in correspondence with the existing pillars and are connected to them by means of post-tensioned threaded bars.IMAGE 2: Redevelopment project of the portion of the industrial building object of the intervention: plan view of the first floor (a) and of the section (b).Building B: state of affairsThe second intervention involved part of a prefabricated industrial warehouse built in the mid-1980s, with a total surface area of ​​approximately 3500 m2, consisting of various adjacent rectangular bays which, overall, make up an irregular shape.Originally divided into lots and with a single floor above ground, the original building has undergone repeated interventions over the years, such as the addition of an intermediate floor in some spans and the merging of several lots into one.All the structures of the original compartment are prefabricated, while the subsequent additions are made of cast-in-situ concrete and steel.The portion of the building that is the subject of this report consists of two different adjacent and communicating warehouses.The first, arranged on two levels with a brick slab, has dimensions of 15.00 x 20.50 m, the second, also on two levels, has dimensions of 10.00 mx 35.00 m and has a steel floor.The latter, made with IPE400 main beams and IPE100 distribution crosspieces, was completed with a sheet of metal sheet with a thickness of only 4 mm.The whole structure was supported by square piers in steel 100 mm x100 mm bound at the base to the industrial flooring and, halfway up, to the masonry in vibrocompressed blocks.IMAGE 3: Current state of the portion of the industrial building object of the intervention (the parts to be demolished are highlighted in yellow): plan view of the first floor (a) and of the section (b).Project statusThe intervention was aimed at replacing the existing steel floor, characterized by obvious vibration problems and the absence of suitable foundations to guarantee the load-bearing capacity of the floor requested by the client.For this new intervention, it was decided to create a new structure, detached from the pre-existing one, in order not to alter the seismic response of the entire complex.The newly built deck - which will be better described in §2.3 - is supported by a prefabricated structure consisting of L-shaped lateral cap beams, with spans ranging from 6.50 m to 8.00 m, and prefabricated pillars with a rectangular section 50 cm x 30 cm with squat shelf at the top, eccentricity at the base equal to 45 cm with respect to the foundation plinths of dimensions 2.00 mx 1.35 mx 0.90 m, connected to each other by curbs of dimensions 40 cm x 50 cm.The newly built FRC ceiling is put in communication with the ground floor by inserting a stair-lift shaft with a plan size of 4.75 m.x 4.35 m.with new foundation size 4.90 mx 4.65 m.IMAGE 4: Project of the portion of the industrial building object of the intervention: plan view of the first floor (a) and section (b).[...] The article continues in the attached PDF.Further details on the constructions will be provided and the executive phases will be described.The article was presented during the second edition of the fib Italia YMG Symposium on Concrete and Concrete Structures (Rome, November 18-19).DOWNLOAD * AND READ THE FULL ARTICLE* Upon free registration on the INGENIO website Register or log in to download the pdf (*) (*) If after logging in you still do not see the link to the document, try to refresh the page.Read also Organomineral nanocomposites for durable concreteRedevelopment of the building stock: GBC Italia presents the new condominium protocolQualification of efficient district heating and cooling systems: GSE online operating procedureSuperbonus: the Notariat explains when it can be taken even with building differencesGas: all the news on reduced VAT and contributions for businessesMinister Cingolani: "In 2030, decarbonising by 55% compared to 1990 is possible, also thanks to geothermal energy"EUCENTRE: the 9 degrees of freedom test system is active for studies on the reduction of seismic riskElectric and sustainable mobility: other simplifications in the new MIMS decreeThermal baths with walkways, swimming pools and wooden platforms: the CILA is not enough, you need a building permitLighting sector: revenues of almost 25 billion euros are expected in the five-year period 21-25The procurement delegation is law: reduction of design levels, CAM, fair compensation ok apart in exceptional casesRedevelopment of the building stock: GBC Italia presents the new condominium protocolGalleries: Cte organizes a conference on ring coverings of prefabricated blocks made of TBMIUSS School of Pavia: 4 scholarships for the course, in English, on seismic and hydrogeological riskMCE 2022, contained in pills for an efficient professional updateAdvanced modeling techniques for engineeringThe most important Technical Project Information Portal at the service of Architects, Surveyors, Geologists, Engineers, Experts, technical profession, Professional Register, Professional Rates, Technical Standards, Inarcassa, Structural Project, Seismic Improvement, Architectural Project, Urban Planning, Energy Efficiency, Energy renewables, Recovery, Reuse, Renovations, Free Construction, Procurement Code, Thermotechnical Systems Project, Digital Modeling and BIM, Technical Software, IOT, ICT, Lighting Technology, Work Safety, Fire Safety, Construction Technologies, Forensic Engineering, CTU and Appraisals, Evaluations Real Estate, Certifications.INGENIO-WEB.IT is a periodical publication of IMREADY Srl registered with the Secretariat of State for Internal Affairs of San Marino with protocol no.638/75/2012 of 27/4/2012.Responsible Director: Andrea Dari.Copyright 2022 IMREADY Srl All rights reserved.Privacy Policy, Site created by Global Sistemi CreditsIMREADY Srl, Strada Cardio, n.4, 47891 Galazzano, RSM, Tel. 0549 909090 Mail: secretariat (@)