Numerical Analysis of the Bottom Thickness of Closed Rectangular Tanks Used as Pontoons

Abstract

This paper concerns the numerical analysis of closed rectangular tanks made in one stage, used as pontoons. Such structures can be successfully used as floating platforms, although they primarily serve as floats for ‘houses on water’. Amphibious construction has fascinated designers for many years and is becoming, in addition to a great and prestigious location for many purposes, a practical global necessity. Severe weather phenomena that no country is safe from, i.e., heavy rains or floods, combined with the scarcity of space intended for the construction of residential buildings, encourage development at the contact of water and land or on water only. This paper contains an analysis of the static work of tanks with different bottom thickness subjected to hydrostatic load acting on tank walls and the bottom plate and evenly distributed load acting on the upper plate, i.e., major impacts that occur when tanks are used as pontoons. Calculations were made using the finite difference method in terms of energy, assuming the Poisson’s ratio ν = 0. Based on the solutions obtained, charts were made that illustrated the change in bending moments at the characteristic points of the analysed tanks depending on acting loads. The article also includes calculations of buoyancy, stability and the metacentric height for tanks with different bottom thicknesses, with the main purpose being to improve and share knowledge on their safe use as pontoons.

The Effect of Subgrade Coefficient on Static Work of a Pontoon Made as a Monolithic Closed Tank

“…The subject matter has been taken up in numerous outstanding and fundamental scientific works [17][18][19][20][21][22][23][24][25][26][27][28][29][30]. The method has been used in calculations regarding plate structures [9,31,32], tanks [7,8,33] or surface girders. This work also used the condition for the minimum energy of elastic deformation accumulated while undergoing bending in the plate resting on the elastic substrate.…”

“…The results of the stability and metacentric height calculations presented later in the article were obtained on the basis of the procedures provided for in Australian Standard AS 3962-2001 [35]. The schematic drawings of the pontoon (cross sections) used to verify its buoyancy and stability are shown in Figure 2a,b, respectively [8].…”

“…The presented calculations show that increasing the weight of the pontoon reduces the tilt angle. Therefore, if it was required to reduce the tilt angle to a value below 6 • , the thickness of the bottom plate should be increased while maintaining the remaining parameters [8]. exceed 15°.…”

“…The solution always poses a risk of inaccuracies in assembly, subsequent leaks and shorter use [6]. A more advantageous solution, although more computationally and executively challenging, is to design and produce a tank as a single, ready-made element, possible to be built without any additional construction work [7,8]. Typisation and prefabrication are two of the most important directions in construction today.…”

“…To minimize the risk of the pontoon filling with water, it was tightly filled with Styrofoam. The literature on the subject provides few publications on closed tasks made in one stage [7,8] and taking into account the effect of the substrate, which-for the pontoon in question-was Styrofoam [9]. Since the technical literature has not yet provided solutions for this type of tank taking into account the effect of its substrate, it was decided that a dedicated numerical analysis would be performed for the purposes of this study.…”