Prefabricated building foundations.What precautions should be followed for calculation and verification?|

2022-07-19 19:08:25 By : Ms. linda lian

As a rule, when it comes to prefabricated building foundations, almost all prefabricators do not carry out the calculation of the foundation structures but, on the contrary, provide the so-called "drains (stresses) at the foot of the pillars" which allow the calculation and verification of the foundations same by other designers appointed by the client.In fact, although very often there are still stair and / or elevator partitions that can more or less interact with the prefabricated structure, nowadays the circumstance (in the past frequently used also as a term of commercial negotiation) that they are the same prefabricators calculate the foundations.In fact, the designer of a prefabricated building, be it an architect, an engineer or a surveyor, is almost never his computer.Generally the calculation is the responsibility of the prefabricator's technical office which, in some cases, is also required to calculate the foundations.Furthermore, already the advent of the NTC 2008, has in fact considerably increased the number of load conditions, with the consequent increase in the related resulting stresses.This makes it objectively not easy to "disentangle" the amount of information output from the structural calculation of the prefabricated building transmitted by the technical offices of the various prefabricators to the designers of the foundations, both for what concerns the pillars but, more importantly, for what concerns the partitions staircase / elevator.Furthermore, the verifications and construction rules relating to the foundations dictated by the NTC lead to compliance with dimensional parameters that strongly constrain the designers of the same.Not infrequently, however, we see foundation structures which, although they must originate from the same principles and rules, have totally different dimensional and reinforcement characteristics, this depending on the more or less literal application of the calculation rules themselves (e.g. verification overturning, connecting beam heights, etc.).Fig.1_Foundations built on site (sole, glass and panel support beam) © Prefabricated buildings_Maggioli EditoreIn order to clarify a subject so widely debated, the trade association of prefabricators (Assobeton) has issued guidelines that provide precise indications for a correct sizing and calculation of the foundations.Obviously, almost all the structural elements that make up the foundations of prefabricated buildings are substantially influenced by the different "interpretations", more or less stringent, of the provisions contained in the standard, such as those relating to the dimensions of the soles, the reinforcement, the thickness of the walls of the glasses (or wells) and to the panel support beams.For the latter, as shown in fig. 2, various technical measures allow, in compliance with the standard, significant material savings in terms of concrete and reinforcement.Fig.2_Tapered panel support beam diagram © Prefabricated buildings_Maggioli EditoreAgain with a view to saving material and optimizing the functional use of the prefabricated elements, the adoption of the so-called “indented pillars” makes it possible to significantly “shorten” the length of the pillar itself in the foundation socket.Fig.3_ “Indented” pillar scheme © Prefabricated buildings_Maggioli EditoreAnother technology, for the foundations of prefabricated buildings, which allows to save significant volumes of concrete and excavation, is that which provides for the pillar-foundation connection through appropriate mechanical systems such as Peikko, Halfen, Armatubo, etc.This technology, more widely adopted in some Italian regions, finds an application confirmation where, due to problems related to the depth of the excavations (groundwater, soil stratification, etc.), it is important to avoid the construction of glasses or wells (for the embedding of the pillar) to contain the excavation itself.Fig. 4_Pillar-foundation connection diagram (rendering) © Prefabricated buildings_Maggioli EditoreFinally, the entirely prefabricated foundation systems meant that, in the final analysis, this structural design part also belongs to the various prefabricators.39.00 € 35.10 € Buy on www.maggiolieditore.itStay updated on the news of the technical networkRead the latest engineering industry newsGet a preview of the new publications - ebooks and books - and buy them with an online discountThe contents edited by the editorial staff of are elaborated and viewed by Simona Conte, Giulia Gnola, Gloria Alberti.The technical insights are aimed at an audience of professionals who intend to stay updated on industry news.We see below the schematizations to be made for the calculation of the pillars.More than the configurations to maximize shear and moments (as for beams), they concern the method of combining the loads to establish the value of the axial action that the column will have to bear.Logically, to dimension and verify the entire pillar it is sufficient to check the [...]The columns of the steel structures are connected to the foundation, generally made of reinforced concrete, by means of a plate bolted to a counter plate equipped with anchor bolts.The structure of the plate with log bolts and log bolts are nothing more than round steel, with a diameter generally from 24 mm onwards (with a smaller diameter in the case [...]In carrying out the calculation checks it is necessary to consider specific types of loads that weigh on the structure.Which ones are they?Here is a brief overview that collects the different categories.The standard provides for the following structural loads to be considered for the purposes of the verifications: permanent structural loads (G1);permanent non-structural loads (G2);accidental loads (Q);seismic loads [...]The document "Structural design notebooks - 7: seismic improvement and adaptation interventions with steel - Part 2" by Fondazione Promotion Steel is the second of a series of notebooks dedicated to seismic adaptation and improvement interventions of existing buildings with the use of steel.Part 1 of the "Structural design notebooks - 7: interventions of [...]Liquefaction of soils is a phenomenon of reduction of shear strength due to an increase in pore pressure which occurs in saturated granular soils, inducing: a) significant permanent deformations;b) conditions of practically zero effective stresses with consequent loss of shear strength.On the Italian territory, due to its characteristics of seismicity (not very high) [...]The idea behind the dry system is contained in its very name "dry".Building without the use of water in the assembly process, by layering materials on a resistant internal frame: this is the secret of the dry system.An accurate preliminary design and the use of quality pre-finished material are essential for dry construction [...] is the portal dedicated entirely to engineers.The contents of the site, completely free, allow designers to read every day in-depth articles on topics relevant for professional updating: from energy certification to anti-seismic, from renewable energy sources (photovoltaic, geothermal, biomass, wind, solar thermal ) to architectural design, from updating ..Stay updated on the news of the technical networkRead the latest engineering industry newsGet a preview of the new publications - ebooks and books - and buy them with an online discount© 2022 Maggioli Editore.Maggioli SPA p.VAT number 02066400405