جستجوی مقالات مرتبط با کلیدواژه « static loading » در نشریات گروه « عمران »

Nowadays, the use of composite columns in construction projects is more attention than in the past. The use of composite columns in the construction of airports, sports stadiums, marine and oil platforms is more than other projects. Due to the fact that during the operation of the mentioned projects, the possibility of incidents such as; Collision of a ship with a structure, a severe storm, in marine platforms or things like fire and explosion in all projects, and also on the other hand, the high importance of these structures requires researchers to research provide more about providing solutions to increase the resistance of composite columns in structures so that the structure can show more resistance against the above incidents. In this research, it has been tried by modeling samples with different parameters in the Abaqus finite element software, the effect of changing variables such as; Geometrical parameters, compressive strength of concrete and type of cross section of members; Determine the strength of composite columns against static load. After modeling the samples and analyzing and processing the results, it was found that; The use of square cross section in composite columns and also increasing the compressive strength of concrete used in these members will have a positive effect on the performance of composite members and these two items improve the resistance to static load by 19% and 10% respectively. to forgive Also, reducing the ratio of width to thickness (b/t) increases the strength and resistance of joints and improves the bearing capacity of the joint.

Deep foundation are used to transfer loads of large and high rise building to subsurface layers that have sufficient strength. Piles are one of the most common deep foundations which are installed in the form of driven an bored for many years, the high noise and variation by the driving and the hardness and the limitations of the performance of the bored piles caused to use a new type of pile which installed to the soil using torque and a small amount of axial compressive load, Helical pile can be considered as such piles. Drilled displacement piles are another type of this piles. Due to the increasing use of these piles, there are still limit studies on them and there is a need to study their behaviour in different soils and conditions. Three models of piles in the laboratory section were implemented and loaded in FCV-AUT and compared with studies in the field. Compressive and tensile static load were performed according to ASTM D1143 and ASTM D3689 standard and rapid loading test.Drilled displacement pile in tensile and compressive performance was better than other torque driven pile. Because of concrete is cheaper than steel, these piles can be a good alternative for driven and bored pile in urban areas.

Nowadays, RC or Combined diaphragm walls are vastly used for deep excavation. This type of retaining structures consists of some piles, which are tied-back using the anchors and anchored from their toe to the ground. Concrete or wood plates were used between them. In order to evaluate the effects of some parameters on wall deflection and its internal forces, several models of combined diaphragm walls were selected and analyzed using FLAC software. Before developing the models, Lim and Braiud (1999) case study was modeled with FLAC2D and results were compared with the experimental results indicating acceptable accuracy of the modeling. The numerical model simulates the soldier piles with beam elements and the anchors with cable elements. The soil model used is a modified hyperbolic model with unloading hysteresis. The complete sequence of construction is simulated including the excavation and the placement and stressing of the anchors. The numerical model is calibrated against an instrumented case history. Then a parametric study is conducted. The parameters which is evaluated are: distance and stiffness variation, the bonded and un-bonded length of the anchors, the angle of the anchors and the first raw anchor location. By comparing the different parameters it was observed that the variation of the flexural stiffness of the soldier piles and variation of the bond length of the anchors contain the highest and lowest effect on the maximum horizontal displacement of the wall, respectively. Other analytical results consisting wall deflection vs. geometric characters of the wall are presented and discussed.