Search the digital library catalog

Abstract: The master thesis presents the findings of the review of the design documentation of PGD plans for the PK-16 retaining structure, reconstruction of the G2-108 Hrastnik - Zidani Most road and deviation of the G1-5 Rimske Toplice - Zidani Most - Radeče road. The PK 16 retaining structure is foreseen between the Sava riverbed and the new road. The length of the retaining structure is substaintal (approx. 1140 m), the morphology of the terrain along the wall varies greatly. However, due to the erosion of the Sava River, it is estimated that the wall will need to be deep or corrosion protection should be constructed. Temporary security and work platforms based on the Sava River Basin (which is already impounded and quite deep in this part) will be required. The retaining structure is designed as a vertical cantilever wall that is on the underside rigidly fixed to the horizontal foundation plate. On the bulk of the structure, the foundation plate is supported by piles in two rows. The vertical wall at the top passes into a horizontal cantilever along which a corridor with a fringe runs. The controlling calculations were done employing a computational 2D model that takes into account the elastoplastic Mohr - Coulomb model for soil and the elastic model of concrete structures. The accompanying geotechnical calculations of the retaining structure in profiles P283 and P299 were compared with the analyses made in the design project to confirm the possibility of carrying out the proposed structures.
Keywords: civil engineering, geotechnical design, retaining structures, cantilever walls, piles
Published in DKUM: 13.10.2021; Views: 438; Downloads: 34
Full text (2,99 MB)

Abstract: The present study assesses high squeezing ground confirmed by empirical and semi-empirical theories. High squeezing ground is often present in underground constructions at great depths, but it is hardly ever researched separately from light and fair squeezing ground. A three-dimensional, static numerical model is developed for a complex underground structure consisting of a shaft, a silo, and a mine roadway at great depth, which is certainly in high squeezing ground. Furthermore, a solution for the entire structure based on shotcrete with incorporated yielding elements is provided. The yielding elements, in general, absorb the strain energy by compressing at a relatively constant stress, but without rebounding. A three-dimensional, static numerical model of a support system with incorporated yielding elements is established in order to demonstrate that the presented forces are under control. Therefore, a failure of the lining is avoided because the stresses in the shotcrete lining are below its load-bearing capacity. It can be concluded that yielding elements incorporated in the shotcrete lining play an important role in the support solution in high squeezing ground.
Keywords: high squeezing ground, numerical model, underground structures, deformations, yielding support element
Published in DKUM: 14.06.2018; Views: 821; Downloads: 73
Full text (606,20 KB)
This document has many files! More...

Abstract: The type of a retaining structure as well as the structure configuration mainly depends on geological conditions. If geological, urban and other data allow an alternative, the costs should also be considered as an important factor. In geotechnical practise, pile walls are especially used in excavations, in the erection of traffic facilities and in the sanitation of landslides. This paper is aimed at presenting economical differences between cantilever and anchoring pile walls and the impact of different parameters on costs. The optimization method, which uses mathematical programming, gives an optimal solution to geometry, self-manufacturing costs, and other characteristics of the structure in a uniform optimization process. This paper presents the optimization process using the nonlinear programming (NLP) approach for the anchored pile wall. The application presented only serves to confirm the effectiveness of the proposed optimization method. Therefore, the retaining structure is situated in homogeneous non-cohesive soil at three different soil friction angles of 35°, 30° and 25°. The generalized analytical method, the USA method, which was first introduced by Bowles [3], isused in the application. The analysis of the results shows the impact of parameters, the main controlling factors, configuration geometry and savings. The optimal results allowed from 18 up to 47 per cent savings compared to the cantilever pile wall depending on ground and structure input data and the excavation depth.
Keywords: civil engineering, optimum design, retaining structures, USA analytical method, nonlinear programming
Published in DKUM: 16.05.2018; Views: 911; Downloads: 58
Full text (216,45 KB)
This document has many files! More...

Abstract: The paper deals with the effects and costs of implementing a base isolation system for the mitigation of the seismic risk of an existing steel rack structure. Different realistic distributions of the payload mass and occupancy levels, which form different plan asymmetric variants, have been analysed. The results obtained by the pushover analysis (N2 method) are presented as top floor envelopes and as plastic hinge damage patterns. In the presented cost study, the cost of the implementation of the proposed base isolation system is compared with the estimated costs of structural repairs to the damaged structural members of the superstructure, as well as with estimated expenses of the downtime period. The results have shown that base isolation is, in general, not economically feasible for lower ground motion intensities, whereas it could be of great benefit in the case of moderate and high intensities, especially if the downtime period is taken into account.
Keywords: rack structures, seismic behaviour, base isolation, cost efficiency, mass eccentricity, pushover analysis
Published in DKUM: 07.08.2017; Views: 892; Downloads: 126
Full text (999,00 KB)
This document has many files! More...

Abstract: Advanced pore morphology (APM) foam, consisting of sphere-like metallic foam elements, proves to have advantageous mechanical properties and unique application adjustability. Since the APM foam manufacturing procedure has been developed recently, the mechanical characterization of these materials is still very limited. Therefore, the purpose of this research was to determine the behaviour of APM spheres and its composites when subjected to quasi-staticand dynamic compressive loading. The results of the performed research have shown valuable mechanical properties of the composite APM foam structures, offering new possibilities for their use in general engineering applications.
Keywords: advanced pore morphology, foam, composite APM foam structures
Published in DKUM: 26.07.2017; Views: 998; Downloads: 348
Full text (1,61 MB)
This document has many files! More...