Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Deflection

Effect of Dynamic Earth Vibration on the Behavior of Laterally Loaded Single Pile Embedded within Unsaturated Soil

Maha H. Abood; Mahmood R. Mahmood; Nahla M. Salim

Engineering and Technology Journal, 2021, Volume 39, Issue 12, Pages 1748-1752
DOI: 10.30684/etj.v39i12.508

Most of the studies of laterally loaded piles focused on the behavior for piles subjected to static or cyclic lateral loading embedded within dry or saturated soils, few studies investigate the behavior of piles embedded within partially saturated soils and subjected to dynamic loads. In this research, an experimental study presents an aluminum pile model embedded within dry, fully saturated and partially saturated soils, subjected to dynamic load with the El Centro 1940 NS acceleration data (0.05g, 0.15g, and 0.32g) accelerations. Three different lowering levels of the water table for fully saturated soils model is achieved to get partially saturated soils of three different values of matrix suction. During an earthquake model, a liquefaction phenomenon is observed by boiling of sand and completed collapse in the soil as shown in the results. It is concluded that the resisting to the bending moment reduced by 22%, 50%, and 57% after 1st, 2nd and 3rd lowering of water level respectively, than that of the saturated condition. This reduction approaches to 28% for completely dry soil. It is worth to mention, that, the deflection of the pile reduced as the lowering of water level increased. The soil resistance increases with the increasing of dynamic load acceleration. The soil resistance increases about 35% when the acceleration increase from 0.05g to 0.15g and an increase of about 22% when the acceleration increases from 0.15g to 0.32g.

Size Effect on The Shear Strength of Reinforced Concrete Beams

Hind T. Jaber; Kaiss F. Sarsam; Bassman R. Muhammad

Engineering and Technology Journal, 2021, Volume 39, Issue 12, Pages 1960-1976
DOI: 10.30684/etj.v39i12.2283

According to research, as the depth of a beam increases, the section's shear strength can be expected to decrease. The size effect is a phrase that has been used to describe this tendency. Testing of unreinforced specimens under shear has also shown that the shear strength might be lower than what is typically anticipated in the design. As a result, it is critical to comprehend the behavior of these structures, as they may be influenced by a size impact. Sixteen reinforced concrete beams of different rectangular cross-sections without stirrups were tested. The tested beams were simply supported made of high-strength reinforced concrete subjected to two equal concentrated loads up to the failure. The experimental results showed that all of the beam specimens failed in shear except one which had failed by flexure. Moreover, increasing beam height from 150 to 250 mm has decreased the cracking and ultimate shear strength ratio for all groups except for group four when the beam height increased from 150 to 300 mm the cracking and ultimate shear strength ratio has increased. Furthermore, increasing beam depth from 150mm to 300mm has led to increasing the ultimate load besides decreasing their final deflection at the same level of load, which is the apparent size effect in the stiffness of the tested beams.