Doctoral Thesis

Flexible buried structures

Final Thesis 37.74 MB Summary of Thesis 3.88 MB

Author of thesis: Ing. Vladimír Houšť, Ph.D.

Acad. year: 2014/2015

Supervisor: prof. Ing. Jiří Stráský, DSc.

Reviewers: doc. Ing. Ladislav Klusáček, CSc., doc. Ing. Vladislav Hrdoušek, CSc., Prof. Ing. Jiří Barták, DrSc.

Abstract:

The thesis is devoted to analysing of flexible buried arch structures. Modelling of the flexible concrete arch is carried out via a nonlinear finite element model that accounts for soil constitutive relations, soil-structure interactions, sequential construction stages and soil compaction. Advanced FE-model was verified by measurement obtained by full-scale field testing of two buried arches.
Mathematical optimization methods of genetic algorithms and Levenberg-Marquardt method are applied to already calibrated complex computational models in order to reduce bending and associated flexural stresses in the concrete section of buried arch. Centre line of the arch is parameterized by cubic Bezier curve to reach interpolation of thrust line.
Optimization technique is applied with extensive parametrical study which shows the optimal shapes for buried arches of various span/rise ratios, backfill depths and foundation soil types. For practical application are given coordinates of Bézier curve control polygons of particular resulting shape.
Subsequently is applied optimization method for a theoretical reduction of tensile stresses obtained by shape optimization of previously verified numerical model of buried arch.
Comparisons of earth pressure, bending moment axial force and deflection of flexible structure during sequential construction of different span/raise ratios of buried arches are presented. The behaviour of flexible buried arch with effect of local traffic load model LM1 has been analysed via 3D finite elements model with respect to different depth of backfill above crown.

Keywords:

soil-structure interactions, flexible concrete arch, buried structures, cut-and-cover structures, buried arch bridges, wildlife crossings, shape optimization, genetic algorithm, Bézier curve, earth pressures, ANSYS

Date of defence

13.01.2015

Result of the defence

Defended (thesis was successfully defended)

znamkaPznamka

Language of thesis

Czech

Faculty

Department

Institute of Concrete and Masonry Structures

Study programme

Civil Engineering (D-K-C-SI (N))

Field of study

Constructions and Traffic Structures (KDS)

Supervisor’s report
prof. Ing. Jiří Stráský, DSc.

File inserted by supervisor Size
18587.pdf 75,17 kB

File inserted by the reviewer Size
22478.pdf 86,87 kB

Reviewer’s report
doc. Ing. Vladislav Hrdoušek, CSc.

File inserted by the reviewer Size
18588.pdf 87,62 kB

Reviewer’s report
Prof. Ing. Jiří Barták, DrSc.

File inserted by the reviewer Size
18748.pdf 232,75 kB

Responsibility: Mgr. et Mgr. Hana Odstrčilová