Dengfeng Fu

Bio: Dengfeng Fu is an academic researcher from Tianjin University. The author has contributed to research in topics: Bearing capacity & Geotechnical engineering. The author has an hindex of 5, co-authored 6 publications receiving 59 citations. Previous affiliations of Dengfeng Fu include Australian Research Council.

Uniaxial capacities of skirted circular foundations in clay

Abstract: Results of finite-element analyses calculating the undrained capacities of skirted circular foundations under uniaxial vertical, horizontal, and moment loading are presented. Parallel finit...

Undrained capacity of a hybrid subsea skirted mat with caissons under combined loading

Abstract: Skirted mudmats are commonly used to support offshore infrastructure. However, these may not be able to provide sufficient capacity to notably withstand the lateral loads applied by jumpers and con...

Effects of tension gap on the holding capacity of suction anchors

Abstract: Suction anchors are popular anchoring solutions for station-keeping of offshore floating facilities. For the in-place holding capacity design of these anchors, there is a debate in practice regarding the possibility of developing a tension gap on the rear side of the anchor and how to account for it in design. This study is carried out to shed further light on this debate. Analytical and finite element analyses are reported in this study which investigate: i) the optimal padeye depths and the influencing factors, for both free gapping and no gapping interface conditions; ii) the effect of tension gap on the anchor's holding capacity when the padeye is placed at optimal depths; iii) the effect of tension gap on the anchor's holding capacity when the padeye is placed at non-optimal depths. Strategy to account for tension gap in practical design is provided.

Bearing capacity of a side-rounded suction caisson foundation under general loading in clay

Abstract: A novel side-rounded suction caisson foundation is proposed in this study. Compared to a conventional circular shape in plan, it has a rectangular middle section inserted in between the two circular halves for increased moment capacity. This paper presents an investigation into the bearing performance of this novel foundation in clay under uniaxial and combined loading by means of an extensive finite element parametric analysis. It is found that by adopting a dimensionless equivalent embedment ratio and a dimensionless equivalent strength heterogeneity ratio, which account for the side-rounded shape of the proposed foundation, its design approach can be unified with an existing framework established for conventional skirted circular footings. The advantage of the proposed foundation and the application of the proposed design method is demonstrated through an example application.

Combined Load Capacity of a Preloaded Skirted Circular Foundation in Clay

Abstract: Preloaded foundation capacity has recently been a topic of major interest in offshore foundation engineering The increase in undrained shear strength due to preloading and consolidation en

P-ultimate for undrained analysis of laterally loaded piles. discussion and closure

Abstract: A discussion of a paper with the aforementioned title by Murff and Hamilton, published in this journal (Volume 119, Number 1, January 1993), is presented The discussion focuses on laterally loaded piles in layered soils Maugeri, Castelli, and Motta assert that the authors' method overpredicts the ultimate lateral resistance on the pile Discussion is followed by closure from the authors

A review on recent advancements of substructures for offshore wind turbines

Abstract: The sustainable development of offshore wind energy requires thorough investigations on technological issues. The substructure, which acts as the natural link between technologies and environments, is a critical topic for the offshore wind industry. This paper presents a comprehensive review of variable types of offshore wind substructures associate with their corresponding example projects. The study is complemented with a special attention to a novel foundation, namely suction bucket foundation. Main technological issues related to this concept are integrated. In the paper, bearing behaviors of offshore wind turbines (OWTs) with the suction bucket foundation under lateral loads, vertical loads, combined loads, and extreme loading conditions are discussed. Two installation methods are introduced. The geometric and improved design is illustrated by considering capabilities in transportation and installation. Research methods, including field tests, laboratory tests, centrifuge tests, theoretical analysis and numerical simulations, are listed; these methods are employed in previous studies to investigate behaviors of the OWT. This review integrates most relevant aspects and recent advancements together, which aims to provide a reference frame for future studies and projects.

Capacity of modified suction caissons in marine sand under static horizontal loading

Abstract: Experimental and finite element analyses were conducted on the bearing capacities of modified suction caissons (MSCs) in saturated marine fine sand under static horizontal loading. Results show that the MSC can provide higher horizontal and moment bearing capacity and limit lateral deflection in comparison to a regular suction caisson. The bearing capacity of the MSC increases with increasing external skirt dimensions and the internal compartment aspect ratio, however, decreases with increasing the loading eccentricity. Several equations are proposed to calculate the maximum moment bearing capacities, which take the external skirt width, the internal compartment aspect ratio and the loading eccentricity into account. The deflection and the net earth pressure distribution methods are used to determine the rotation center position and these two methods are proved to be satisfactory. It is found that the rotation center moves downwards and forwards with increasing horizontal loading, then tends to be a stable position when the maximum load is approaching. The distance between the rotation center and the caisson lid at failure decreases with increasing external skirt dimensions, the internal compartment aspect ratio and the loading eccentricity. Based on the simulation results, an expression to estimate the combined capacity of the MSC was proposed.

Parametric study of hybrid monopile foundation for offshore wind turbines in cohesionless soil

Abstract: The hybrid monopile foundation is an alternative for offshore wind turbines. The parametric study has been performed through a series of centrifuge tests for the optimal design of the hybrid foundation. The wheel diameter, wheel thickness, and pile length are considered in the analysis. The lateral capacity of the hybrid monopile foundation increases with the wheel diameter and tends to accelerate; it increases linearly with the wheel thickness and pile length. The influence of the wheel diameter is more pronounced compared to the other parameters. The hybrid monopile demonstrates an enhanced performance compared to the monopile and the single-wheel. The improvement is more significant at small pile lengths. The hybrid monopile shows its advantages in reducing the pile length. It has great potential in reducing capital costs. An analytical method is proposed by scaling the individual capacity of the pile and the wheel. A design chart for the scale factor is suggested. The calculation is applicable for determining the initial dimension of the hybrid monopile foundation, and the ultimate lateral capacity is assessed.

Load bearing behaviors of composite bucket foundations for offshore wind turbines on layered soil under combined loading

Abstract: This paper focuses on the load bearing behaviors of the composite bucket foundation (CBF) which has been proposed and applied to offshore wind turbines in China. With the numerical analysis method, the soil-structure interaction and the practical project-based dimensional and property parameters are described. The load bearing behaviors of the CBF are investigated in terms of deformations (structure and soil), load bearing ratios, and geometric effects. Under the consideration of multi soil profiles and combined loading condition, the load bearing behaviors of the CBF can be concluded. Soil property can change the load bearing ratio especially when the compartment plates are involved. The lid-bearing mode is dominant for CBF when the upper layer of the soil is high in strength. Without the compartment plates, the bucket wall contributes more than the lid. The load bearing behavior is influenced by the bucket diameter, soil strength and the compartment plates. The results are of reference value to understand the load bearing behaviors and serve as a basis for optimizing the structure design for cost-reduction.