An Experimental Study on Unit Side Resistance of Gaziantep Limestone

In this study, the correlation between the uniaxial compressive strength and unit side resistance of Gaziantep limestone was investigated experimentally for dry and fully saturated conditions. The results were compared with the methods given in the literature which correlate these two parameters. The linear correlations significantly overestimated the measured side resistance values for all tests while the non-linear methods generally overestimated the unit side resistance under fully saturated conditions but provided a reasonable estimation for dry samples. As a result, a linear correlation and non-linear correlation ranges for estimating the unit side resistance of such limestones were also suggested

Poenostavljen pristop za oceno posedanja temeljne plošče na pilotih

In this study, a simplified approach to the settlement estimation of piled rafts resting on over-consolidated clay deposits is presented. For this purpose, a series of plane-strain and three-dimensional analyses were performed and their results are compared with the available data in the literature. It was found that the percentage decrease in the total settlements with the addition of piles with respect to the unpiled case is very closely estimated by both the plane-strain and the three-dimensional, simplified, numerical analyses. Using this phenomenon, a simple method of analysis is suggested for the total settlement estimation of the piled raft foundations and design charts are provided for the cases studied (for the specific soil conditions only) throughout this study.Vlaga zgoščenih zemljin se po vgradnji v zemeljske objekte uravnoteži z okolico. V pogojih vlažne in zmerne klime se glinene zemljine, ki so se kompaktirale na suhi strani Proctorjeve krivulje, dodatno navlažijo. Proces vlaženja spremlja zniževanje sukcije in dodatne deformacije, ki so lahko nabrekanje ali strukturni kolaps. Preiskave zemljin iz glinenih nasipov so pokazale, da se sukcija uravnoteži pri vrednostih pod ca. 300 kPa. V prispevku predstavljamo rezultate raziskav, opravljenih na zgoščenih zemljinah, v okviru katerih smo konvencionalne raziskave dopolnili z meritvami sukcije. Na izbranih vzorcih, ki smo jim določili retencijsko krivuljo, smo merili sukcijo pri različnih stopnjah zgoščenosti. Po preplavitvi smo v edometru opazovali deformacije, ki so se v odvisnosti od začetnega stanja odražale kot nabrekalni dvižki ali kolaps. S primerjavo podatkov smo ugotovili, da začetna sukcija nabitih vzorcev pomembno vpliva na značaj deformacij ob vlaženju in bi v prihodnje lahko služila kot pomemben kazalnik V študiji je prikazan poenostavljen pristop za oceno posedanja temeljnih plošč na pilotih, ki ležijo na sedimentiranih prekonsolidiranih glinah. Za ta namen je bil izveden niz ravninsko deformacijskih in tridimenzionalnih analiz, njihovi rezultati pa so bili primerjani z razpoložljivimi podatki iz literature. Ugotovljeno je bilo, da je bil delež znižanja celotnih posedkov s piloti glede na primer brez pilotov zelo natančno ocenjen z obema - ravninsko deformacijsko in poenostavljeno tridimenzionalno numerično analizo. Zaradi tega je predlagana enostavna metoda za oceno posedanja temeljnih plošč na pilotih. Za obravnavane primere (samo za določene pogoje temeljnih tal) pa so podani tudi projektni diagrami za oceno posedanja temeljnih plošč na pilotih

A SIMPLIFIED APPROACH TO THE SETTLEMENT ESTIMATION OF PILED RAFTS

In this study, a simplified approach to the settlement estimation of piled rafts resting on over-consolidated clay deposits is presented. For this purpose, a series of plane-strain and three-dimensional analyses were performed and their results are compared with the available data in the literature. It was found that the percentage decrease in the total settlements with the addition of piles with respect to the unpiled case is very closely estimated by both the plane-strain and the three-dimensional, simplified, numerical analyses. Using this phenomenon, a simple method of analysis is suggested for the total settlement estimation of the piled raft foundations and design charts are provided for the cases studied (for the specific soil conditions only) throughout this study

Compaction and CBR properties of RAP/sand blends in Iraq

Nowadays, Iraq is experiencing a rapid reconstruction process during which a significant amount of construction waste material is generated. One of such materials is RAP (reclaimed asphalt pavement) which is obtained from the removal of surface pavement of roads and used especially as an aggregate substitute in asphalt mix, granular base and sub-base material for roads, or as road fill material. From this point of view, the primary objective of this study was to evaluate the possible effects of adding sand to RAP in terms of compaction and strength properties and to suggest a possible recycling application. For this purpose, RAP and sand samples were collected from Iraq. Then, RAP/sand blends were prepared by mixing RAP with 5%, 10%, 15%, 20%, 25%, and 50% sand by weight. Modified Proctor Compaction and California Bearing Ratio (CBR) tests were performed on these samples. The results have revealed that the compaction properties of the RAP/sand blends were significantly improved as compared to RAP samples resulting in increased maximum dry density and optimum moisture content. CBR values of the tested mixtures had also increased with increasing sand content similar to the results of previous studies. The primary finding of this study was that RAP/sand blends with a sand content of 20% or more were defined to be suitable for use as road fill material according to the American Association of State Highway and Transportation Officials (AASHTO) standards in terms of tested parameters, providing a new field for recycling of RAP in the studied region

Stability of EG cylindrical shells with shear stresses on a Pasternak foundation

This article is the result of an investigation on the influence of a Pasternak elastic foundation on the stability of exponentially graded (EG) cylindrical shells under hydrostatic pressure, based on the first-order shear deformation theory (FOSDT) considering the shear stresses. The shear stresses shape function is distributed parabolic manner through the shell thickness. The governing equations of EG orthotropic cylindrical shells resting on the Pasternak elastic foundation on the basis of FOSDT are derived in the framework of Donnell-type shell theory. The novelty of present work is to achieve closed-form solutions for critical hydrostatic pressures of EG orthotropic cylindrical shells resting on Pasternak elastic foundation based on FOSDT. The expressions for critical hydrostatic pressures of EG orthotropic cylindrical shells with and without an elastic foundation based on CST are obtained, in special cases. Finally, the effects of Pasternak foundation, shear stresses, orthotropy and heterogeneity on critical hydrostatic pressures, based on FOSDT are investigated

Effects of shear stresses and rotary inertia on the stability and vibration of sandwich cylindrical shells with FGM core surrounded by elastic medium

The vibration and stability of axially loaded sandwich cylindrical shells with the functionally graded (FG) core with and without shear stresses and rotary inertia resting Pasternak foundation are investigated. The dynamic stability is derived based on the first order shear deformation theory (FSDT) including shear stresses. The axial load and dimensionless fundamental frequency for FG sandwich shell with shear stresses and rotary inertia and resting on the Pasternak foundation. Finally, the influences of variations of FG core, elastic foundations, shear stresses and rotary inertia on the fundamental frequencies and critical axial loads are investigated