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Evaluation of Design Methods for Driven Piles and Drilled Shafts
Published in Chong Tang, Kok-Kwang Phoon, Model Uncertainties in Foundation Design, 2021
It is worthwhile to note that Eurocode 7 (CEN 2004) does not provide partial factors as a function of the degree of understanding. Nonetheless, engineers have the discretion to choose a characteristic value suitable for the conditions at their specific project sites. However, it is difficult to imagine how an engineer could make an informed decision about the characteristic value in a complex design setting without guidance from data analysis, be it statistical or otherwise. For example, there is no guidance on how the characteristic value concept can be applied to multiple correlated soil parameters (Ching et al. 2020). In addition to elaboration on the use of numerical methods within Eurocode 7 cited in Section 4.4 of Chapter 4, another two key changes of the next generation of Eurocode 7 Part 1 (EN 1997-1:202x) are (1) revision of the geotechnical category and its application and (2) the implementation of consequence class and geotechnical complexity class in achieving the reliability required by the Eurocodes (Franzén et al. 2019). According to prEN 1997-1:2018 (CEN 2018), the geotechnical category in Table 6.16 is based explicitly on the consequence class (i.e. highest, higher, normal and lower) and geotechnical complexity class (i.e. higher, normal and lower). They are closely related to the degree of site understanding. Modifiers for partial factors may depend on the geotechnical category, if specified by a national standard body (Franzén et al. 2019).
Design of Groundwater Lowering Systems
Published in Pat M. Cashman, Martin Preene, Groundwater Lowering in Construction, 2020
In the authors’ experience, the design of groundwater control systems is typically not governed in detail by national or international design standards. This is unlike some forms of geotechnical engineering design (for example related to the design of piles or earth retaining structures), where requirements may be set out more formally in design standards. For example, while Eurocode 7 (BS EN 1997-1:2004) includes a section on dewatering, it limits its requirements to relatively general comments that the design should be based on the results of ground investigations, that the objective of design should be to achieve stable excavations, and that dewatering systems should be reliable and subject to monitoring. This approach of setting ‘high level’ requirements without setting prescriptive limits on possible design methods is common with design standards in some other parts of the world.
Life expectation of wooden foundations - a non-destructive approach
Published in Koen Van Balen, Els Verstrynge, Structural Analysis of Historical Constructions: Anamnesis, Diagnosis, Therapy, Controls, 2016
R.K.W.M. Klaassen, A. Jorissen, H. Keijer
After all data are collected and the calculations are made a final judgement of the quality of the pile foundation should be given. Therefor three checks need to be carried out: 1. The foundation construction must be able to transfer the loads from the construction in a proper way to the piles. This check is in fact a visual judgement. None of the wooden components of the foundation construction may be broken of heavily deformed and the piles must be placed under the brickwork of the walls; 2. The geotechnical pile bearing capacity must be sufficient for the loads from the construction according to Dutch National Annex to NEN-EN 1997-1+C1 (Eurocode 7); 3. The bearing capacity of the timber of the piles and the horizontal elements must be sufficient, and the lowest value obtained by Formulas 4/5 and 6 (pile and horizontal element) is taken into account. It is clear that if one of these checks is negative or settlements are too high (e.g. >3 mm/year) or unequal causing distortion in the building, reparation measurements are necessary. On the other hand it is clear that if calculations show that the bearing capacity for a building is sufficient and no or minor settlements occur the foundation can be classified as stable for a period of 25 years more. If the results are less clear and the bearing capacity of the building showed intermediary values and moderated (<3 mm/year) but homogeneous settlements the judgement to intervene on the quality of the foundation is done on the basis of a combination of the parameters described, sometimes in combination with yearly evaluation on the settlement based on levelling the monitoring bolts (see F3O 2013). Depending on the results the foundation can function for a period between 10 and 25 years more. 4 CONCLUSION
Serviceability performance of buildings founded on rubber–soil mixtures for geotechnical seismic isolation
Published in Australian Journal of Structural Engineering, 2023
Hing-Ho Tsang, Duc-Phu Tran, Emad F. Gad
EN 1997, also known as Eurocode 7 (EN 1997–1:2004; EN 1997–2:2007), sets forth the design principles and requirements for safety and serviceability in relation to the geotechnical aspects of the design of buildings and civil infrastructure. Detailed design rules or models are given in the informative Annexes. Section 6 of Eurocode 7 Part 1 (EN 1997–1:2004) discusses various aspects of the design of foundations, including pad, strip, spread, raft and pile foundations. The Annex H in Part 1 of Eurocode 7 (EN 1997–1:2004) specifies the limiting values of structural deformation and foundation movement, in terms of the total permanent settlement, relative (or differential) settlement, angular distortion, and the like. Both serviceability and ultimate limit states for different types of structures are considered.
Honing safety and reliability aspects for the second generation of Eurocode 7
Published in Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, 2019
The current Eurocodes consist of a suite of 10 European Standards, EN 1990 to EN 1999, providing a common approach for the structural and geotechnical design of buildings and other civil engineering works with, at present, 58 parts (i.e. European published standards). The head Eurocode, EN 1990, provides the rules for the basis of design, i.e. the principles and requirements for safety, serviceability and durability of structures that are common to all the Eurocodes parts, including the partial factors on actions, i.e. loads. EN 1991 provides the requirements for the actions on structures, while the other Eurocodes provide the design rules in the case of all the major construction materials, including EN 1997, i.e. Eurocode 7 – Geotechnical Design, with the rules for design involving ground material, i.e. soil, fill and rock. The current EN 1997 has two parts, Part 1: General rules and Part 2: Ground investigation and testing.
A new approach to predict the compression index using artificial intelligence methods
Published in Marine Georesources & Geotechnology, 2019
Mohammed Amin Benbouras, Ratiba Kettab Mitiche, Hamma Zedira, Alexandru-Ionut Petrisor, Nourredine Mezouar, Fatiha Debiche
As a result of different civil engineering structures, stress is increasing in the soil layers inducing the settlement phenomenon. It should be noted that the geotechnical engineers are responsible for computing the amount of expected settlement as close as possible for the safety of projects (Park and Lee 2011). In particular, marine soils that are extremely soft generate considerable construction problems through settlement (Kim and Do 2011). The computation of compressibility parameters of soils, such as compression index (Cc) using the oedometer laboratory test, based on Terzaghi’s consolidation theory, is particularly important (Kurnaz et al. 2016). Despite the crucial importance of this test, previous studies have shown its major disadvantages, including costliness, unwieldiness, and being time-consuming, in addition to its relying on graphical methods, which usually require personal experience and qualified workforce (Kurnaz et al. 2016). So far, many researchers have tried to develop practical and quick solutions using artificial intelligence methods, such as artificial neural networks (ANN), genetic programming (GP), and multiple regression analysis (MRA), for predicting the difficult-to-obtain parameters from other easily obtained soil parameters. Empirical equations are very important for solving many problems while gaining time, money, and effort (Ameratunga, Sivakugan, and Das 2016; Kang et al. 2011). This importance is evident in the requirement addressed to geotechnical labs in the first section of Eurocode 7 (EN 1997-1), published by the European Committee for Standardisation, to use at least two types of empirical correlations in the geotechnical study associated to any project (Dysli and Steiner 2013; Ameratunga, Sivakugan, and Das 2016).