Caisson

About: Caisson is a research topic. Over the lifetime, 4238 publications have been published within this topic receiving 20283 citations.

Characteristics of Wave Pressures According to the Installation Location of the Caisson Superstructure under Regular Waves

Abstract: In recent years, coastal and port structures have attempted to prevent wave-overtopping or provide waterfront areas by installing superstructures on the structural crowns. In general, in the design stage, the Goda formula acting on the front the structure is applied to calculate the wave pressure acting on the superstructure in consideration of the wave-runup of the design wave. However, the wave pressure exceeding the Goda wave pressure could generate depending on the installation location of the superstructure where the wave-overtopping occurs. This study analyzed the applicability of the Goda formula to the wave pressure calculation for the superstructure of the vertical structures through hydraulic model experiments and numerical simulations. Furthermore, this study investigated the magnitude of the wave pressure acting on the superstructure based on detailed numerical results. As a result, the wave pressure acting on the superstructure was up to 120% higher than the maximum wave pressure on the still water surface. In addition, the wave pressure increases exponentially with the Froude number computed by the overtopping water depth at the crown of the structure, and we proposed an empirical formula for predicting the wave pressure based on the Froude number.

A simplified assessment of the load bearing capacity of suction caisson for offshore wind turbines based on finite element analysis

Abstract: Suction caisson is widely used for offshore wind turbine applications. Its loadbearing capacity depends on the bucket geometry and its embedded soil properties. This paper presents a simplified assessment of the loadbearing capacity of suction caisson based on finite element analysis using the Plaxis 2D program. The load-bearing capacity of the suction caisson is determined based on the resulting load-displacement curve via the tangent intersection method. In addition, this study developed an equivalent equation exploring the relationship between the load-bearing capacity of the suction caisson and the surface foundation. The findingsin the study showed that the geometry of the suction has a significant influence on its loadbearing capacity. The suction caissons whose aspect ratios are larger resulted in higher loadbearing capacities. Besides, the equivalent equation in this study could be applied to effectively estimate the load-bearing capacity of suctioncaisson based on its geometry. The finite element program and the soil ground model analyzed in this study was only an assumption. In the future, experimental studies should investigate the loadbearing capacity of a suction caisson related to its geometry and the embedded soil profile using centrifuge models and large-scale models.

Dry Parallel Seismic: A Novel Method for Determining Thickness of Buried Concrete Pad Foundations

Abstract: The structural capacity of concrete foundations supporting, for example, telecommunications and electrical transmission towers depends, among other things, upon the thickness of the concrete foundation. Current methodology for investigating the thickness of concrete foundations nondestructively has largely been focused upon deep foundations, such as caissons, and in situations where the top of the foundation is exposed. For example, the parallel seismic (PS) method is a borehole method that uses the arrival times of waves imparted in a foundation at a sensor next to a buried foundation to detect the thickness of the foundation but is typically used for deep caisson type foundations. However, in many instances, these foundations are pad and pier type footings that can be buried deep below ground and can be relatively thin, for example, less than 45 cm in thickness. The objective of the present work is to present a nondestructive method for determining the thickness of concrete pads with no direct access. The dry PS method was developed to determine the thickness of thin, buried concrete foundations. The method was first used to verify the as-built thickness, as mentioned in the engineering drawings of a guyed tower dead-man block. Second, it was used to determine the thickness of the pad foundations of five telecommunication towers with pad and pier concrete foundations in South Asia. These towers had foundation thicknesses ranging from 16 to 36 cm, as verified through excavation. Analysis of the data collected during dry PS testing resulted in a mean absolute error (MAE) of 18 mm, which equates to approximately 6% error. Thus, this paper demonstrates that the dry PS method overcomes the limitations of the current methodology and is capable of accurately determining the thickness of buried concrete foundations.

ZEEpod Lightweight Structure Installation

Abstract: ZEEpod is a tripod-based structure that is designed for shallow water and could be the possible attractive solution for marginal fields. ZEEpod platform for this project is consist of main caisson, guide sleeve, top sleeve, conductors, topside, subsea template, raker piles and bridge. The offshore execution started with installation of the main caisson supporting the deck structure followed by the guide sleeve and top sleeve installation. The raker piles were then inserted via the sleeves and driven to the required penetration depth. Conductors were subsequently driven, and topside was installed afterwards prior setting down the bridge. The platform installation was successfully completed in October 2021. It has again proven that the ZEEpod platform is technically feasible for the installation at water depth up to 70m. This technology gives benefits in term of its simplicity in fabrication, transportation, and offshore installation. It has resulted to less complexity of construction, lower resources, simplified loadout method and shortened construction duration. With advantages to have a completed platform component, fit into a single transportation barge and with lower capacity installation crane barge required, it is a cost-effective solution which bring value to the project. The aim of this paper is to highlight the concept, engineering analysis and methodology for ZEEpod platform installation as well as the technical challenges during offshore execution. This paper should be an interest to those who seek for alternatives in designing and installing a minimum facilities platform for cost-effective field development at shallow waters.

Soil Investigation Analysis Bearing Capacity of Caisson Foundation Makassar City Bblk Service Building

Abstract: Soil investigation is an effort to obtain underground information for planning civil building foundations. The existence of a soil investigation can determine the bearing capacity of the foundation. One type of foundation that is planned is a caisson foundation. Soil investigation includes, among others, soil drilling, soil sampling, field testing and laboratory testing. A Referring to the technical data, the caisson foundation plan scheme used has a diameter of 60-1000cm, the selection of the most suitable diameter is adjusted to the load plan of the superstructure while the foundation depth is recommended to pass through a bedrock layer of 20-30cm. Technically, the soil layer is sufficient to withstand vertical loads, this is indicated by the value of Qc>150kg/cm2 and NSPT>60, but the location of the building is on sloping land with the distribution of bedrock layers that have a slope following the profile of the soil surface, so the potential for uplift is ) can occur due to lateral forces, this is also supported by the uneven embankment material from the original soil surface profile so that the load acting is uneven on the embankment layer.