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GEOSTRUCTURAL ANALYSIS OF THE ATHENIAN ACROPOLIS WALL BASED ON TERRESTRIAL LASER SCANNING DATA

by Dimitris Egglezos

Co authored with D. Moullou and D. Mavromati, Published in "The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences". Vol. XXXVII. Part B5. Beijing 2008

Analytical relationships for earthquake induced pore pressure in sand, clay and silt

by Dimitris Egglezos

Estimating earthquake induced settlements on granular soils – Application to shallow foundations

by Dimitris Egglezos

published in 2nd Japan-Greece Workshop on Seismic Design, Observation, and Retrofit of Foundations, Japan, Tokyo, 2007

The article presents a set of general relationships for permanent volumetric strain from cyclic
loading. These... more The article presents a set of general relationships for permanent volumetric strain from cyclic
loading. These relations can be used to predict earthquake induced settlements on granular soils,
with direct application to shallow foundations. Volumetric strain is calculated at the end of each
loading cycle for the following cases: drained or undrained conditions, isotropic initial stress state
(σ΄1=σ΄3, e.g. free field) or anisotropic initial stress state (σ΄1≠σ΄3, e.g. initial static shear), constant
cyclic stress or constant cyclic shear. The variables of the general relations are based on statistical
analysis of experimental data from drained cyclic triaxial tests and relate directly to the initial stress
or strain state and density of the soil element. The accuracy of predictions is examined through
comparison with a) experimental data b) well established charts from other researchers and c)
measured settlements due to earthquake, from reported cases histories.

EMPIRICAL RELATIONS FOR EARTHQUAKE PORE PRESSURE BUILD-UP IN GRAVEL

by Dimitris Egglezos

published in Proceedings of 4th International Conference on Earthquake Geotechnical Engineering June 25-28, 2007

In terms of this paper a method is proposed for prediction of earthquake induced excess pore pressure
in gravelly... more In terms of this paper a method is proposed for prediction of earthquake induced excess pore pressure
in gravelly soils. Prediction is based on empirical relations initially developed for sands (Egglezos,
2004). The main idea is the introduction of an equivalent void ratio of clean sand (ees) - in substitution
of gravel nominal void ratio eo - which leads to similar pore pressure build-up. This idea is based on
the finding that pore pressure build-up from cyclic loading in gravel, (qualitatively at least) follows
similar path to that of clean sand, but gravel at a given relative density and gravel content, develops
excess pore pressure corresponding to a sand of higher density. The empirical relations applies to
triaxial stress conditions, but extension to free field conditions is easily attained, through simlpe
assumptions.
The procedure for the estimation of “equivalent void ratio” ees is based upon statistical analysis of
experimental data. These data originate from cyclic triaxial tests in gravel mixtures or natural gravels
reported in relevant literature (e.g. Evans M.D., 1995, Kokusho, 1994 etc).
The accuracy of the proposed method is examined with comparison of predictions with published
experimental data from cyclic tests on gravel. As a conclusion the proposed method for calculation of
earthquake excess pore pressure in gravel a) is characterized of great simplicity, b) uses as input
parameters the initial stress and density state of soil and c) agrees well with published experimental
data from other researchers and d) can apply equally to gravelly sands (practically for gravel content
GC 65%) and sandy gravels (GC>65%).

SIMPLIFIED PREDICTION FOR EARTHQUAKE INDUCED SETTLEMENTS OF GRANULAR SOILS

by Dimitris Egglezos

published in Proceedings of 4th International Conference on Earthquake Geotechnical Engineering, June 25-28, 2007

The article presents a set of general relationships for permanent volumetric strain from cyclic loading.
These... more The article presents a set of general relationships for permanent volumetric strain from cyclic loading.
These relations can be used to predict earthquake induced settlements of granular soils.
The empirical relations predict volumetric strain of sands at the end of each loading cycle and apply
to the following cases: drained or undrained conditions, isotropic initial stress state ( = 3, e.g. free
field) or anisotropic initial stress state ( 3, e.g. initial static shear), constant cyclic stress or
constant cyclic shear.
The variables of the general relations are expressed in simple dimensionless mathematical forms with
parameters directly related to the initial stress or strain state and density of the soil element.
The empirical relations apply to triaxial stress conditions, but extension to free field conditions is
easily attained, through simlpe assumptions.
The empirical relations are based on statistical analysis of experimental data from drained cyclic
triaxial tests.
The extension of empirical relations for prediction of settlements in case of undrained loading is
realized with adequate transformation of formulation of the empirical relations for drained conditions.
This transformation is based on the well established correlation between pore pressure build up in
undrained conditions and (restrained) volumetric strain (Rowe, 962).
The accuracy of predictions is examined with a) comparison with experimental data from drained
cyclic tests reported in relevant literature b) comparison of predicted volumetric strains with well
established charts from other researchers (e.g.: Ishihara and Yoshimine ( 992), Tokimatsu and Seed
( 987)) and c) comparison with measured settlements from earthquake, at sites reported in literature.

Protective filling of ancient monuments. The case of the Arrephorion on the Athenian Akropolis

by Dimitris Egglezos

Back - analysis sheds light on the history of the Acropolis Wall: The interpretation of a permanent structural failure

by Dimitris Egglezos

Co-authored with D. Moullou, published in XV ECSMGE European Conference

This work describes a back-analysis for the interpretation of a serious structural failure observed in an area of the... more This work describes a back-analysis for the interpretation of a serious structural failure observed in an area of the Acropolis North Circuit Wall. The failure occurred, according to the available historical and archaeological evidence, at the end of the 18th or beginning of the 19th century and it includes a) the collapse of the upper part of the Wall in the area examined (the crown of the Wall that had been constructed of architectural members of the entablature of the Old Temple of Athena), b) significant out-ward lean from the vertical (7 cm) of the remaining lower part (the part beneath the crown that collapsed), c) rotation of approx-imately 1o d) systematic cracking of the outward face of the wall. For the analysis, the principles of rock mechanics were applied for simulation of the dry-masonry construction. Since the damage was primarily attributed to a strong earthquake motion, for the problem description information is drawn from a wide range of scientific specialization. The analyses comprised: 2-D FE elas-toplastic analysis, simplified (pseudostatic) spectral dynamic analysis and a rigorous 2-D time history analysis. The results are proven very satisfactory. Τhe permanent displacement of the current crown of the wall, the rotation of the structure, the collapse of the entablature members (form Γ) and the systematic net of fractures at the outward side of the wall are consistently predicted. Therefore, the assumption that the damage was caused by an earthquake was also verified, limiting the termini of the event be-tween 1785 and 1805.

ESTIMATION OF EARTHQUAKE INDUCED DRY SETTLEMENTS OF CFR DAMS

by Dimitris Egglezos

published in Proceedings of the 4rth Japan- Greece Workshop, October 2011, Kobe Japan.

ABSTRACT: The estimation of dry settlement, arising from seismic action, is a significant
factor for the proper... more ABSTRACT: The estimation of dry settlement, arising from seismic action, is a significant
factor for the proper design of rockfill dams. This applies particularly to Concrete Face Rockfill
(CFR) Dams, where the deformed (due to the settlement) dam geometry imposes increased
stress upon the concrete slab of the upstream face. In this work, a simple method for calculating
dynamic dry settlement in CFR dams is presented, based on simple empirical relations for a) estimating
settlement on sand from earthquake (Egglezos 2008), and b) calculating a notional value
of void ratio for gravel (instead of the actual value) in order to simulate dynamic behavior of
gravel to that of an imaginary sand material referring hitherto as “equivalent sand” (Egglezos,
2010). The application of these empirical relations allows the estimation of rockfill settlement,
through relevant equations for sand (Egglezos 2007, 2010). The results from the empirical relations
apply directly to a 2-D ordinary static FE analysis, in order to obtain the post earthquake
stress-strain field and the permanent deformation (vertical settlement and lateral spreading) induced
from the seismic shock. The deformed geometry of the CFRD may be exploited for determining
the concrete slab stress state, aiming to an effective design.

The use of modern technological applications for restoring the circuit Walls of the Acropolis

by Dimitris Egglezos

published in Acropolis Restoration News 10, 2010