Murat Ornek

Estimation of ultimate loads of eccentric-inclined loaded strip footings rested on sandy soils

Apart from the vertical axial loads, the footings of portal-framed buildings are often subjected to eccentric and eccentric-inclined loads caused by forces of earth pressures, earthquakes, water, wind, etc. Sometimes the corner of the column of these portal-framed buildings is located very close to the property line and hence subjected to eccentric and eccentric-inclined loading. The study presented herein describes the use of artificial neural networks (ANNs) and multi-linear regression model for the prediction of ultimate loads of eccentric and eccentric-inclined loaded strip footings. The data used in running of network models have been obtained from extensive series of laboratory model tests. The parameters investigated are the eccentricity ratio, the load inclination angle, the footing size, and the density of sand soil. A total of 50 laboratory model tests with four different footings rested on loose and dense sand have been performed. The eccentricity ratio (e/B) and inclination angle (i) changed from 0 to 0.5 and 0° to 30° with vertical direction, respectively. The measured ultimate load response of the strip footings has been compared with available theoretical prediction. The results of the experimental study proved that the soil density, the load eccentricity, and the load inclination had considerable effects on the load of the strip footings, and the ANN model serves as simple and reliable tool for predicting the behavior of eccentric and eccentric-inclined loaded strip footings.

Field Test of Circular Footings on Reinforced Granular Fill Layer Overlying a Clay Bed

The ultimate bearing capacity and settlement of a circular shallow rigid plate on compacted granular fill layer with and without geogrid reinforcement overlying on natural clay deposit exhibiting low bearing capacity and large settlement have been investigated. A total of 15 field tests were carried out using a circular model rigid plate with a diameter of 0.90 m. This study has been initially directed to evaluate the beneficial effects of the compacted granular fill layer on natural clay deposit for the shallow rigid plate performance. Then, the reinforcing effect of the top granular fill layer with horizontal layers of welded geogrid reinforcement on the bearing capacity and settlement has been studied. Parameters of the testing program include granular fill thickness, depth of first reinforcement, vertical spacing of reinforcement layers, and number of reinforcement layers. Bearing capacity ratio (BCR) and percentage reduction in settlement (PRS) were defined to evaluate improvement performance. Based on the test results, the effect of the granular fill and welded geogrid reinforcement on the bearing capacity and settlement are discussed. The results indicate that the use of granular fill layers over natural clay soils has considerable effects on the bearing capacity and settlement characteristics. The construction of granular fill layer with welded geogrid reinforcement over clay deposit helps in redistributing the applied load to a wider area. It has been observed that the use of welded geogrid reinforcement in granular fill layer provides additional improvement of bearing capacity and provides reduction in settlement of the rigid plate up to 80 and 60 %, respectively.

Model studies of multi-edge footings on geogrid-reinforced sand

The ultimate bearing capacity of multi-edge shallow footings on loose and dense sand bed with and without geogrid reinforcement has been investigated. The data used have been obtained from extensive series of laboratory model tests. A total of 140 laboratory model tests were carried out using four different model rigid plates with the shapes of +, H, T and square. Parameters of the testing programme include the density of sand soil, depth of first reinforcement, vertical spacing of reinforcement layers, number of reinforcement layers and the covering of the reinforcement layer. Bearing capacity ratio was defined to evaluate improvement performance. The results indicate that the use of geogrid layers in sand bed has considerable effects on the bearing capacity characteristics and the optimum reinforcement parameters are independent from the shape of the footings. The construction of geogrid reinforcement helps in redistributing the applied load to a wider area. It has been observed that the use of geogrid reinforcement in sand layer provides additional improvement of bearing capacity of the multi-edge footings up to four times that of the unreinforced case.

Stress Analyses of Strip and Rectangular Footings Rested on Loose Sands

In this study, the stress, the bearing capacity and the settlement behavior in the loose sandy soils were investigated experimentally and theoretically. The study was performed in central loading conditions using strip and rectangular footings. The vertical stresses resulting from the external are measured for three different distances simultaneously. And also the load-settlement curves were obtained. The results showed that the bearing capacity increases when the length of the footing increases and the measured vertical stress values decrease along the depths for all the three types of the footing types. The test results were compared with theoretical results given in the literature. As seen from this comparison, the experimental results are in accordance with the theoretical results.

Kare Temeller Altında Gerilme ve Taşıma Gücü Analizi

Bu calismada, gevsek kum zemine oturan 4 farkli model kare temel altinda meydana gelen dusey gerilme artislari ve tasima gucu degisimleri deneysel ve teorik olarak arastirilmistir. Ilave dusey gerilme artislari 4 farkli derinlikte (12,5 cm, 25 cm, 37,5 cm ve 50 cm) yerlestirilen gerilme olcer ile olculmustur. Deney sonuclari, Newmark yontemi ile karsilastirilmistir. Ayrica yuk-oturma degerleri ise yuk hucresi ve deplasman olcerler vasitasiyla elde edilmistir. Deneyler, Iskenderun Teknik Universitesi Insaat Muhendisligi Bolumu Geoteknik Laboratuvari’nda yapilmistir. Sonuclar incelendiginde, deneysel ve teorik sonuclar arasinda bir uyum oldugu gozlenmistir. Ayrica temel oturum alani arttikca tasima gucu degerleri de artmistir.