A Comparative Study of Piers with DSCT and Steel Piles

Because of climate changes, the demand for securing marine space is increasing owing to problems such as sea level rise, design wave height increase, and lack of land and space, and research on the development of a new high-performance pier has been conducted. In the existing pier supported by steel piles, buckling failure and corrosion problems may lead to a risk of structural safety, and maintenance is difficult owing to a narrow span. The new type of double-skinned composite tubular (DSCT) structure, which has been extensively studied recently, is filled with concrete between the inner and outer tubes, increasing the strength of concrete because of the three-axis confined effect. In addition, it is advantageous in terms of ductility. Furthermore, owing to the hollow cross-section, it is economical because it weighs less than the concrete-filled steel tubular (CFT) structure, effectively saving materials. In this study, the performance of a pier with 30 steel piles and that of a pier supported with 20 DSCT piles was compared under the same external force through finite element analysis. Consequently, it was confirmed that the pier with DSCT piles showed higher performance in displacement and stress than the existing pier with steel piles.

Perencanaan Ulang Pondasi Pilar Jembatan Sikabu Kayu Gadang

The construction of transportation facilities such as bridges plays an important role in the development of human resources today because more and more road users will use these facilities. The Sikabu Kayu Gadang Bridge has a span of 100 meters with a structure of precast concrete, abutments, pillars and a foundation of concrete and steel piles which inspired the authors to conduct research. In this type of selection, several things need to be considered, such as the load being carried and the location of the hard ground. Based on this, this study aims to analyze the deep foundation that can be applied to the project in the hope of getting more efficient results. Based on the re-planning, the bearing capacity of the foundation permit (Qall) is 1254.98 kN with a diameter of 0.5 m and a depth of 20 m. The permitted bearing capacity of the pile group (Qall) is 12795.46 kN to withstand the loads acting on the superstructure. Bore Pile foundation logitudinal reinforcement = 10 D16 and Bore Pile shear reinforcement = ᴓ 12 – 150 mm.

Multiaxial Fatigue Life Assessment of Integral Concrete Bridge with a Real-Scale and Complicated Geometry Due to the Simultaneous Effects of Temperature Variations and Sea Waves Clash

In the present study, the authors attempted to predict the fatigue lifetime of a real-scale integral concrete bridge with H-shaped steel piles resulting from working and environmental conditions. In this regard, various types of nonproportional variable amplitude loads were applied on the bridge, such as temperature variations and sea waves clash. To this end, CATIA software was used to model the real-scale bridge with its accessories, such as a concrete deck, concrete anchors (walls), I-shaped concrete beams (Ribs), and steel piles. Subsequently, stress analysis was performed to determine the critical area apt to fail. The results showed that steel piles are the most critical bridge components. As a result, in future analysis, the purpose will be to study this critical area, and the effect of relative humidity on the fatigue properties of concrete was ignored. Subsequently, the time history of stress tensor components in the critical area was obtained by performing transient dynamic analysis. Various well-known equivalent stress fatigue theories (von Mises, Findley, Dang Van, McDiarmid, Carpinteri–Spagnoli, Modified Findley, Modified McDiarmid, and Liu–Zenner) were utilized to calculate the equivalent stress caused by the simultaneous effect of temperature variations and sea waves clash. Eventually, the fatigue life of the structure was predicted by employing the rainflow counting algorithm and the Palmgren–Miner damage accumulation rule. The results indicated a reduction in the multiaxial fatigue life of the structure under the simultaneous effects of two phenomena, the daily temperature variations and the sea waves clash, of approximately 87% and 66%, respectively, compared with the fatigue life of the structure under either the effect of temperature changes or the effect of sea waves clash, separately. Therefore, it was necessary to consider all the cyclic loads in the structural design step to estimate the fatigue life of the structure. Moreover, the findings of this case study revealed that the lowest value of multiaxial fatigue lifetime is related to the application of the Liu-Zenner criterion. In other words, this criterion is more conservative than the other used criteria.

Impact of slopes on the lateral resistance of steel piles

A soldier pile and lagging wall is one of the most common types of retaining wall. Solider pile walls develop lateral resistance through the stiffness of the piles and the passive resistance of the soil acting upon the embedded portion of the piles. Ground anchors can also be used when additional lateral resistance is required. Using Broms’ methods, a parametric study was completed to investigate the performance of laterally loaded short and long steel piles installed in a variety of cohesive and cohesionless soils. The results were compared to those generated using RocScience finite element software. RocScience software was then used to evaluate the lateral resistance of piles installed at various distances from the crest of a 2:1 slope. Finally, two soldier pile walls, to be installed within a sloping railway embankment, were designed.

Impact of slopes on the lateral resistance of steel piles

A soldier pile and lagging wall is one of the most common types of retaining wall. Solider pile walls develop lateral resistance through the stiffness of the piles and the passive resistance of the soil acting upon the embedded portion of the piles. Ground anchors can also be used when additional lateral resistance is required. Using Broms’ methods, a parametric study was completed to investigate the performance of laterally loaded short and long steel piles installed in a variety of cohesive and cohesionless soils. The results were compared to those generated using RocScience finite element software. RocScience software was then used to evaluate the lateral resistance of piles installed at various distances from the crest of a 2:1 slope. Finally, two soldier pile walls, to be installed within a sloping railway embankment, were designed.

Extra-long steel piles production and transport of Bridge Mainland – Pelješac, Croatia

Steel pipe pile as one of the foundation forms has the advantage of high bearing capacity, environment protection and installation, which were widely adopted to sea-crossing bridge, offshore wind power and marine oil rig at present. With the development of project scale, the length and diameter of the piles were increasing gradually. Meanwhile, civil engineers had to face the outstanding challenges in the production and transportation of extra-long and extra-large steel pipe piles. The design parameters of steel piles were controlled under the highest and strictest execution class EXC4 B+ in accordance with the European standard EN 1090-2. Additionally, the pile length of 130,6 m set a record for entire pre-fabricated longest steel pile in the field of civil engineering worldwide at that time. All the manufactured piles were delivered by cargo vessel after long voyage to Croatia. The accumulated experience of Pelješac Bridge could be as a reference for similar projects in future.