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Wianamatta Group Foundation design and performance
Published in P.J.N. Pells, Engineering Geology of the Sydney Region, 2018
The maximum allowable bearing pressure is generally determined by calculating the ultimate bearing pressure using accepted soil mechanics principles and dividing by a safety factor. As a rough guideline, the allowable bearing pressure is approximately twice the undrained triaxial shear strength.
Ganjiang Bridge: A High-Speed Railway Long-Span Cable-Stayed Bridge Laying Ballastless Tracks
Published in Structural Engineering International, 2021
Xingwang Sheng, Weiqi Zheng, Zhihui Zhu, Aiguo Yan, Yongping Qin
Galvanized parallel steel wire cables with a standard tensile strength of 1670 MPa are used in the cable-stayed system of Ganjiang Bridge. The total number of cables is 48 pairs, which is a fan-shaped arrangement. External dampers are installed in the cables to suppress the wind-rain vibration, and stainless steel tubes are arranged in a range of 2.5 m at the lower end of the cables. The cable is connected with the main tower through a built-in steel anchor box, and the tension end of the cable is set in the main tower. Besides, a new type of cable-girder anchorage system is used for the connection of the cable and the main girder. The new type cable-girder anchorage structure mainly consists of a steel pipe, a cushion plate, a main plate, and stiffening plates (Fig. 4). The penetration weld is used to connect the steel pipe with the main plate. The cushion plate plays the role of bearing pressure and distributing the cable force, and it is welded to the end of the steel pipe. The main plate is welded to the side web of the steel-concrete composite girder, so that the cable force is transmitted to the side web of the concrete-steel composite girder safely and reliably.
Effects of Near-Fault Pulses on Nonlinear Soil-Structure Systems
Published in Journal of Earthquake Engineering, 2018
Hamid Masaeli, Ramin Ziaei, Faramarz Khoshnoudian
The yield strength of the soil is determined using formulas with respect to Vs of soil. The correlation of strength with Vs of soil is based on an empirical formulation proposed by Tezcan et al. [2010]. This method stems from a variety of case histories of site investigations, including extensive borehole data, laboratory testing, and geophysical prospecting at more than 550 construction sites. The proposed empirical expression corroborates consistently with the results of the classical theory of Terzaghi and Peck (1967). More importantly, experimental data of plate load tests carried out at different sites further confirm the validity of the proposed method. The proposed method consists of only two soil parameters, (a) the in situ measured Vs and (b) the unit weight of the soil. The unit weight may also be determined with sufficient accuracy by means of another empirical expression proposed, using the P-wave velocity. According to the proposed method, once the shear- and P-wave velocities are measured in situ by an appropriate geophysical survey, the allowable bearing pressure as well as the coefficient of subgrade reaction and many other elasticity parameters may be determined reliably for both soil and rock. Further details on the proposed method are available in [Tezcan et al., 2010].
Influence of reinforcement stiffness and strength on load-settlement response of geocell-reinforced sand bases
Published in European Journal of Environmental and Civil Engineering, 2018
Mohsen Kargar, S. Majdeddin Mir Mohammad Hosseini
At higher ranges of settlement, the geocell performance would be enhanced as catenary shape deformation occurs and the membrane effect of the geocell reinforcements develops a tensile force in the reinforcement. The vertical component of this force resists the downward movement of the footing and increases the bearing pressure. By increasing the level of footing pressure and settlement, the sand in the geocell pockets beside the footing width starts to move upward as it overcomes the frictional resistance and the excessive bending of the reinforced sand cushion causes high levels of horizontal tensile strains in the bottom axis of geocell walls located beneath the centre of footing width. At this stage, the points below the middle axis of geocell walls under the footing centre undergo large strains up to the ultimate strain and rupture happens in the geocell. Consequently, a sudden shear failure takes place leading to a large heave in the soil surface beside the footing width and the infill soil of the geocell moves out of the pockets.