Elevated Water Tower Research Articles

Optimizing the water distribution network of community water supply using different computer simulation techniques

The appropriate operation of a water distribution network (WDN) of any water supply scheme is vital to supply sufficient potable water to consumers at sufficient pressure. However, the performance of the WDN may vary from the original design in the long run. In this study, a WDN network model was built using WaterGEMS and WaterCAD computer simulators, and hydraulic analyses were conducted to obtain an optimal WDN for a community water supply scheme of a village in Sri Lanka. A series of steps such as; selection of models, network representation, simulation of network, problem identification, network configuration finalization, and results analysis were carried out in developing the WDN simulation model. The hydraulic parameters such as pressure, flow velocity, and flow rate were analyzed under extended period simulation. The result indicated that the nodal pressure head in the junctions (100%) is above the required pressure level of 10 meters H2O, which is adequate for the effective performance of the water distribution system (WDS) during peak and off-peak demand hours. The elevated water tower was optimized with a 10 m height to supply water at satisfactory pressure. Nodal pressure is negatively correlated with ground elevation. The flow velocity was observed within the range of 0.1-0.4 m/s in 67% of the pipe network, while 17% of the pipe network velocity was below 0.1 m/s. The low daily water demand of the small community could be the reason for the low-velocity scenario, which shall lead to silt deposition in the pipelines; hence frequent line washout to eliminate the silt deposition in the system is recommended. The WDN was designed for optimized pipe sizes with availability in the market.

Seismic response of the elevated concrete water tower considering liquid–solid–soil interaction

In the present study, the elevated concrete water tower is used as the research object. In order to investigate the ground motion response law of the elevated concrete water tower with the near-field Chichi wave, the near-field no-pulse Tehachapi Pump wave and the far-field long-period Tianjin waves when the liquid–solid–soil interaction (LSSI) is considered. And the finite element calculation model of the elevated concrete water tower and foundation with different liquid storage rate was established and the dynamic time history analysis was also conducted. The calculation results demonstrate that when considering LSSI, the elevated concrete water tower exhibits different response characteristics under the action of three types of seismic waves. Under the action of pulsed seismic waves in the near field, the seismic response of the elevated water tower structure is the most intense, followed by the far-field long-period seismic wave, and the response in the near-field no-pulse seismic wave remains the least.

Seismic analysis and retrofit of the oldest R/C elevated water tank in Florence

The seismic performance of an elevated water tower with reinforced concrete staging structure—the oldest one in Florence—is analyzed in this paper. The tower, erected in 1905, is a major achievement by engineer Attilio Muggia, an Italian pioneer of reinforced concrete, and is now classified as modern heritage architecture. The structure is characterized by an atypical bracing layout, with all braces rising from the bottom left corner to the upper right corner at each bay of the three upper staging levels, and no braces on the first level. The time-history assessment study, carried out by a detailed finite element simulation of the water–tank dynamic interaction, shows unsafe response conditions of the first level columns starting from seismic action scaled at the basic design earthquake level. Based on these data, two retrofit measures are proposed, consisting either in integrating the existing reinforced concrete braces of the staging skeleton with additional steel braces, or incorporating a seismic isolation system, and namely a set of double curved sliders on top of the underground columns. From an architectural viewpoint, the former strategy meets the requirement of leaving the original staging elements exposed, whereas the latter causes no intrusion in the superstructure. The design criteria and technical installation details of the two systems are illustrated, along with the results of the seismic performance assessment analyses in both rehabilitated conditions, including the cost estimation of the interventions.

On the convergence of the dynamic series solution of a constrained elastic column subjected to wind gust

The one dimensional problem of analysing the dynamic behaviour of an elevated water tower with elastic deflection–control device and subjected to a dynamic load was examined in [2]. The constrained elastic system was modeled as a column carrying a concentrated mass at its top and elastically constrained at a point along its length. A new solution technique, which yielded a series solution to the problem, was then developed. This paper is basically concerned with establishing the convergence of the series solution obtained in [2] and hence, the acceptance of this solution as the actual solution of the constrained elevated water tower vibration problem. Damping is neglected.Journal of the Nigerian Association of Mathematical Physics Vol. 8 2004: pp. 157-160

Progress in large vessel forming: introduction of some innovations of Prof. Z.R. Wang

Large size vessels are widely used as LPG spherical tanks, elevated water towers, vacuum simulators for the space environment, landmarks and others. Prof. Z.R. Wang has supervised several engineering projects in which he has innovated manufacturing technologies. In this paper, some cases of large vessels manufactured by one of his inventions, integrated hydro-bulge forming, are described. Also the new large flange forming method and the new flexible reconfigurable discrete die for forming curved shell petals are introduced.

Recent Advances in Liquid Sloshing Dynamics

A liquid free surface in partially filled containers can experience a wide spectrum of motions such as planar, non-planar, rotational, quasi-periodic, chaotic, and disintegration. Civil engineers and seismologists have been studying liquid sloshing effects on large dams, oil tanks and elevated water towers under ground motion. Since the early 1960’s, the problem of liquid sloshing dynamics has been of major concern to aerospace engineers studying the influence of liquid propellant sloshing on the flight performance of jet vehicles. Since then, new areas of research activities have emerged. The modern theory of nonlinear dynamics has indeed promoted further studies and uncovered complex nonlinear phenomena. These include rotary sloshing, Faraday waves, nonlinear liquid sloshing interaction with elastic structures, internal resonance effects, stochastic sloshing dynamics, hydrodynamic sloshing impact dynamics, g-jitter under microgravity field, cross-waves, and spatial resonance. The dynamic stability of liquid gas tankers and ship cargo tankers, and liquid hydrodynamic impact loading are problems of current interest to the designers of such systems. This article will address the means of passive control of liquid sloshing and the use of liquid sloshing forces to control vibratory structures. Other important contributions include the development of digital computer codes to solve complex problems that were difficult to handle in the past. The purpose of this article is to review the research work developed in different applications. It will highlight the major achievements and results reported in the literature. Some early work will be cited very briefly in order to provide an updated bibliography of liquid sloshing dynamics. This review article contains 1,319 references.

Parametric Excitation of Nonlinear Elastic Systems Involving Hydrodynamic Sloshing Impact

The parametric excitation of an elevated water tower experiencing sloshing hydro-dynamic impact is studied using the multiple scales method. The liquid sloshing mass is replaced by a mechanical model in the form of a simple pendulum experiencing impacts with the tank walls. The impact loads are modeled based on a phenomenological representation in the form of a power function with a higher exponent. In this case the system equations of motion include impact nonlinearities (selected to be of fifth power) and cubic structural geometric nonlinearities. When the first mode is parametrically excited the system exhibits hard nonlinear behavior and the impact loading reduced the response amplitude. On the other hand, when the second mode is parametrically excited, the impact loading results in complex response behavior characterized by multiple steady state solutions, where the response switches from soft to hard nonlinear characteristics. Under combined parametric resonance, the system possesses a single steady-state response in the absence and in the presence of impact. However, the system behaves like a soft system in the absence of impact and like a hard system in the presence of impact.

Parametric and autoparametric vibrations of an elevated water tower, part I: Non-linear parametric response

The non-linear dynamic response of an elevated water tower subjected to a prescribed harmonic vertical motion of its base is examined. The mathematical model includes the interaction of one liquid sloshing mode with one structural mode. The Struble method of asymptotic expansion is used to determine the conditions of parametric resonance and the corresponding system responses. Under the condition of principal parametric resonance of the first normal mode the system response is found to possess the characteristics of hard non-linear systems. On the other hand, the response exhibits the characteristics of soft non-linear systems when the second normal mode is parametrically excited. The parametric normal mode interaction is found to take place under the combination parametric resonance of the summed type while it does not exist for the difference type. The absence of the system response at combination resonance of the difference type is mainly attributed to the fact that the linearized system is always parametrically stable at this condition.

Parametric and autoparametric vibrations of an elevated water tower, part III: Random response

The random response characteristics of a non-linear two degree-of-freedom system subjected to wide-band random excitations are determined. The Fokker-Planck equation is used to derive a general differential equation for the response joint moments. The equation is found to consitute an infinite coupled set of differential equations which are closed by using a cumulant non-Gaussian closure scheme. In the neighborhood of a fourth order autoparametric resonance condition the non-linear modal intetaction is found to take the form of energy exchange between the normal modes. Contrary to the Gaussian closure solution, the non-Gaussian closure yields a strictly stationary response in the time domain. The response mean squares, fourth order moments, and fourth order cumulants are presented as functions of the internal resonance detuning for various system parameters. It is found that unbounded response statistics take place at certain regions above and below the exact internal resonance ratio of the system. For regions well remote from the exact internal resonance condition the system exhibits the linear response characteristics.

Dynamic Analysis of an Elevated Water Tower Subjected to Wind Gust

The analysis of a column carrying a concentrated mass and subjected to a dynamic load is presented in its general form. The water tower is given as a specific example. Despite the singularity in the mass distribution function of the system, a closed form solution to the response problem is obtained. The Green function for the differential problem has been developed thus making the analysis applicable to any dynamic load.

Dynamic aseismic design of an elevated water tower

Dynamic aseismic design of an elevated water tower

Dynamic aseismic design of an elevated water tower

The paper deals with the dynamic aseismic design of an elevated irrigation water-tower, 150 ft (45 meters) high, capacity approximately 500 tons, to be erected in series in Northern Greece. The water capacity of the tower's reservoir amounts to approximately 500 tons. The dynamic investigation of the tower's behaviour under seismic action was carried through in the writer's Laboratory in Athens, with the use of a properly equipped electronic analog computer, model TR48-3 of Electronic Associates Inc., Long Branch, New Jersey. In addition to the assumption of a rigid foundation, the influence of the rotation of the foundation's footing in proportion to an estimated foundation modulus (Bettungsziffer) was investigated. The solution is given in the form of diagrams, recorded on the computer's plotter, representing the deformations and stress components along the tower's height with respect to time, due to a harmonic seismic earth motion of a given maximal acceleration but of variable frequency. The comparison between rigid and yielding foundation leads to inferences which are exposed at the end of the paper.