FIELD OF THE INVENTION
The present invention relates to overhead water tanks and specifically to the overhead water tanks which can be constructed fast using precast technology.
BACKGROUND OF THE INVENTION
Overhead water tanks have been used since ages to supply water to household and each water tank’s construction takes not less than 5-6 months. Now under Jal Jeevan Mission we need to construct thousands of overhead tanks in next two years which is not possible using traditional methods of water tank construction. Necessity is the mother of invention and so that led us to work on the precast technology in overhead tanks so that we can mass construct tanks in such a small frame of time which is otherwise very difficult to achieve using traditional methods.
Precast technology in concrete structures is used for quite some time now for quick construction and there have been multiple attempts to construct over head water tanks using this technology but all failed due to various technical challenges and lack of sufficient motivation since quick construction was not much of a requirement in these till now. But now without this technology water head tanks project under Jal Jeevan Mission is impossible to deliver which made us work extensively on water head tanks using this technology.
Technically overhead water tank using precast has not been possible till now since temperature variation in India is high and due to which cracks develop between panels which was difficult to prevent and sufficient efforts were not given to find a solution for it.
OBJECTS OF THE INVENTION
The object of the present invention is to develop a precast overhead tank (OHT) in shorter span of time than cast-in-situ.
Another object of the present invention is to develop a precast overhead tank (OHT) with significant reduction in cost.
Yet another object of the present invention is to develop a precast overhead tank (OHT) with increased accuracy and consistent placement of reinforcement as compared to in-situ construction.
Yet another object of the present invention is to develop a precast overhead tank (OHT) with green construction technology as it reduces air pollution, noise and debris on site.
Yet another object of the present invention is to develop a precast overhead tank (OHT) wherein any waste materials are more easily recycled since production is happening at one location and site waste is also less since only finished elements are transported to the construction site.
Yet another object of the present invention is to develop a precast overhead tank (OHT) which requires less labour, equipments and material reducing site congestion.
Yet another object of the present invention is to develop a precast overhead tank (OHT) wherein maximum concrete elements of the structure would be casted at factory and would be assembled using specific types of joints and steel structures at the overhead tank location.
Yet another object of the present invention is to develop a precast overhead tank (OHT) which has specific types of jointing forces which makes them leak proof and capable to bear any weather conditions.
SUMMARY OF THE INVENTION
In this invention overhead water tanks have been designed using precast technology wherein maximum concrete elements of the structure would be casted at factory and would be assembled using specific types of joints and steel structures at the overhead tank location. The invention takes care of all kinds of forces applicable in an overhead water tank and has overcome all the problems faced by engineers who tried to work on precast technology for overhead tanks (OHT) in earlier attempts.
The design requires the construction of all the beams, columns, wall panels at precast factory while OHT foundation, all types of jointing, tank floor screeding, leak-proofing of joints between panels and all other joints would be done cast-in-situ.
The present invention discloses an overhead tank (OHT) comprising beams, columns, wall panels, OHT foundation, all types of jointing, tank floor screeding, leak-proofing of joints between panels characterized in that the overhead water tanks are constructed fast using precast technology.
In an embodiment an overhead tank (OHT) wherein concrete elements of the structure would be casted at factory and would be assembled using specific types of joints and steel structures at the overhead tank location.
In an other embodiment an overhead tank (OHT) wherein the construction of all the beams, columns, wall panels is being done at precast factory.
In yet another embodiment an overhead tank (OHT) wherein OHT foundation, all types of jointing, tank floor screeding, leak-proofing of joints between panels and all other joints would be done cast-in-situ.
In yet another embodiment an overhead tank (OHT) wherein complete base is laid with PCC.
In yet another embodiment an overhead tank (OHT) wherein the top of the column are casted along with corbels (two, three or four) as per their strategic location.
In yet another embodiment an overhead tank (OHT) wherein column is connected to another column using dowel tube connection.
In yet another embodiment an overhead tank (OHT) wherein 5mm thick rubber sheet is used between the two panels to seal the joint thoroughly.
In yet another embodiment an overhead tank (OHT) wherein unique concrete precast block design ensures fully moment resistant joint between two columns.
In yet another embodiment an overhead tank (OHT) wherein unique concrete precast block design ensures fully moment resistant joint between column and beam.
In yet another embodiment an overhead tank (OHT) wherein unique concrete precast block ensures fully moment resistant joint between column, beam and cantilever to support stairs.
In yet another embodiment an overhead tank (OHT) wherein unique concrete precast block ensures fully moment resistant joint between column, beam and cantilever to support pathway at the top .
In yet another embodiment an overhead tank (OHT) wherein corbel design ensures full support to beam’s dead load even before jointing.
In yet another embodiment an overhead tank (OHT) wherein precast walkway slab at tank’s bottom slab level with cantilever is designed in such a way that centre of mass of the component lies on top of beam surface to ensure no toppling of the component.
In yet another embodiment an overhead tank (OHT) wherein skidding with shear reinforcement on deck level panels ensures no differential deflection between two different slabs due to different load between different slabs.
In yet another embodiment an overhead tank (OHT) wherein the design ensures desired safety of the structure under standard wind load and earthquake load.
To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore
not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrative exemplary embodiments and together with the description, serve to explain the disclosed principles. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and with reference to the accompanying figures, in which:
Figure 01 illustrates the SECTIONAL ELEVATION
Figure 02illustrates the PLAN AT FOUNDATION LEVEL
Figure 03 illustrates the REINFORCEMENT DETAILS OF FOUNDATION
Figure 04A illustrates the TYPICAL L-SECTION OF COLUMN
Figure 04B illustrates the SECTION X-X OF FIGURE 04A
Figure 05A illustrates the DETAIL COLUMN TO COLUMN CONNECTION
Figure 05B illustrates the SECTION Y-Y OF FIGURE 05A
Figure 6A illustrates the DETAILS OF CORBEL
Figure 6B illustrates the REINFORCEMENT DETAILS OF CORBEL
Figure 7 illustrates the JOINTING DETAILS OF BLOCK-‘A’ AND BLOCK-‘B’
Figure 8A illustrates the DETAILS OF BLOCK-'A'(ON GRID A1, C1, A3 & C3)
Figure 8B illustrates the SECTION 5-5 & 6-6 of FIGURE 8A
Figure 9 illustrates the DETAILS OF BLOCK-'A'(ON GRID B1, A2, C2 & B3)
Figure 10A illustrates the SECTION 7-7 OF FIGURE 9
Figure 10B illustrates the SECTION 8-8 OF FIGURE 9
Figure 11A illustrates the DETAILS OF BLOCK ‘A’ ON GRID B2
Figure 11B illustrates the SECTION 9-9 AND 10-10 OF FIGURE 11A
Figure 12A illustrates the PLAN OF COLUMN BEAM JUNCTION
Figure 12B illustrates the SECTION 3-3 OF FIGURE 12A
Figure 13A illustrates the PLAN OF COLUMN (WITH BRACKET)
Figure 13B illustrates the SECTION 4-4 of Figure 13A
Figure 14A illustrates the PLAN OF BEAM
Figure 14Billustrates the SECTION 5-5 OF FIGURE 14A
Figure 15 illustrates the DETAILS OF BRACE BEAM B1
Figure 16A illustrates the SECTION 1-1 OF FIGURE 15
Figure 16B illustrates the SECTION 2-2 of FIGURE 15
Figure 17 illustrates the DETAILS OF BEAM B2 AT DECK LEVEL
Figure 18A illustrates the SECTION 6-6 of FIGURE 17
Figure 18B illustrates the SECTION 7-7 of FIGURE 17
Figure 19A illustrates the DETAILS OF BEAM B3 AT DECK LEVEL
Figure 19B illustrates the SECTION 8-8 of FIGURE 19A
Figure 20 illustrates the DETAILS OF BEAM B4 AT ROOF LEVEL OF CONTAINER
Figure 21A illustrates the SECTION 9-9 of FIGURE 20
Figure 21B illustrates the SECTION 10-10 of FIGURE 20
Figure 22 illustrates the PLAN AT BRACE LEVELS - 1,2,3,4
Figure 23 illustrates the BEAM PLAN AT DECK LEVEL
Figure 24 illustrates the SECTION 1-1 of FIGURE 23
Figure 25 illustrates the SLAB LAYOUT PLAN AT DECK LEVEL
Figure 26 illustrates the PLAN OF DECK LEVEL REINFORCEMENT
Figure 27A illustrates the SECTION A-A of FIGURE 26
Figure 27B illustrates the SECTION B-B of FIGURE 26
Figure 28 illustrates the JOINTING AND REINFOCEMENT DETAILS OF TWO WALL PANELS
Figure 29 illustrates the CORNER DETAILS OF WALL PANEL AND COLUMN
Figure 30 illustrates the FIXING DETAILS OF WALL PANEL
Figure 31 illustrates the ROOM BEAM PLAN OF CONTAINER
Figure 32 illustrates the PLAN OF ROOF SLAB REINFORCEMENT
Figure 33A illustrates the SECTION C-C of Figure 32
Figure 33B illustrates the SECTION D-D of Figure 32
Figure 34 illustrates the ROOF SLAB PLAN OF CONTAINER
Figure 35 illustrates the DETAILS OF VENTILATOR
Figure 36 illustrates the PLAN OF STAIRCASE ARRANGEMENT
Figure 37 illustrates the TYPICAL SECTION OF STAIRCASE
Figure 38 illustrates the REINFORCEMENT DETAILS OF FLIGHT
Figure 39 illustrates the LANDING DETAILS AT RL = 4.00, 8.00, 12.00, 16.00
Figure 40A illustrates the SECTION 1-1 OF FIGURE 39
Figure 40B illustrates the SECTION 2-2 OF FIGURE 39
Figure 41A illustrates the STAIRCASE FIXING DETAILS AT LANDING 2.00, 6.00, 10.00, 14.00
Figure 41B illustrates the SECTION 3-3 OF FIGURE 41A
Figure 42 illustrates the DETAILS OF LANDING BEAM LB1 FROM BLOCK ‘B’
Figure 43 illustrates the SECTION 4-4 OF FIGURE 42
Further, skilled structural engineers will appreciate that elements in the drawings are illustrated for simplicity and may not have been necessarily been drawn to scale. For example, the beam and column joints illustrate the loop joint method in terms of the most prominent steps involved to help to improve strength aspects of the present invention. Furthermore, in terms of the construction of the OHT, one or more components of the structure may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.
DETAILED DESCRIPTION OF THE INVENTION
The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments: on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
It is also to be understood that various arrangements may be devised that although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects and
embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes” and/or “including”, when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
In addition, the description of “first”, “second”, “third”, and the like in the present invention are used for the purpose of description only, and are not to be construed as indicating or implying their relative importance or implicitly indicating the number f technical features indicated. Thus features defining “first” and “second” may include at least one of the features, either explicitly or implicitly.
It should be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
Unless otherwise defines, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g. those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
Figure 01 illustrates the complete structure of the precast OHT. As is the case with any precast structure the foundation is always cast-in-situ, similarly here as well the foundation of the OHT is done at site. Above the foundation the column, beams and staircase are casted at factory and assembled using various jointing. At the top stands the tank with pre-casted wall panels and deck level panels with outer precast railing. Over the deck level panels we have cast-in-situ topping.
Various precast elements that have been developed and used in this invention have been designed keeping in mind the following crucial parameters –
• Ease of transportation – Since all the precast elements would need to be transported to the construction site hence the elements are designed such that their transportation is convenient and doesn’t damage them as well
• Ease of lifting – All precast elements are designed with proper provisions for ease during lifting when they are assembled at site
• Ease of installation – Precast elements have been designed keeping in mind its ease of installation
• Time optimization – Time optimization in installation has been kept in mind during the design of the precast elements
• Safety – Safety of the working force during handling of the precast elements on site has been kept in mind during precast elements design
FOUNDATION
Figure 02 illustrates the column plan at the foundation level.
Figure 03 illustrates the typical foundation design of OHT structure which is cast-in-situ. Complete base is laid with PCC. Floor base and base column are cast-in-situ. The top of the column are casted along with corbels (two, three or four) as per their strategic location.
Block A
Refer figure 8A to understand the basic design of block A (ON GRID A1, C1, A3 & C3). Block A is an integral element for the connections between column to column
and as well column to beam. Block B (column element) has four predefined holes (as per requirement it may change) in the vertical direction (through passage for steel bars) for making the joint between column to column. On horizontal face it has steel bar loops for jointing with beam. There are three variations of Block A used in our invention. In first variation it will have steel bar loops on two adjacent face (Figure 08A); in second variation it will have steel bar loops in three faces (Figure 09); while in third variation it will have loops in all the four horizontal block faces (Figure 11A).
Block A has couple of different versions as well to be used at different locations of the structure. At all the corner landing docks Block A (refer Figure 39) is casted along with two adjacent beams on opposite faces to steel bar loops and a square slab between the beams making it a composite monolithic precast structure.
There are four types of block A in which figure 10 A elaborates reinforcement details of block A situated in grid B1, A2, C2, B3 (see figure 36).
Figure 10 B comprises the detail of block A Situated in grid B1, A2, C2, B3. The direction of the cross section is different from figure 10A.
Figure 11B represents the cross section of block A situated in grid B2. Figure 10A, 10B and 11B contains detailing of loop bars in block A.
COLUMN TO COLUMN CONNECTION
Detailed column to column connection can be seen in Figure 05A. Column is connected to another column using dowel tube connection. This is the most popular, most economical, one of the easiest and effective column to column joint. We use rough surface dowel tubes for increased frictional forces between dowel tube and concrete.
One end of the column has steel bars protruding out (of desired anchorage length) while the other end has the dowel tubes with extra margin for steel bars to penetrate within them. Now block A is inserted in the steel bars protruding out from the bottom column which cross the block A and comes out from the top of the block and now the column is erected over block A such that steel bars protruding out of the block A goes inside the dowel tube of another column (Figure 5B). The extra margin between steel
bars and dowel tube is then filled with grouting material (cement-sand mortar) with fast setting admixture from the side holes of the dowel tube in the top column to complete the column-to-column joint with block A in between them.
TYPICAL L SECTION OF COLUMN(Figure 04A & 04B)
Figure 04A represents typical L section of the column. The cross section contains various types of reinforcement bars. It contains details of lapping zone in column which is H/4. Where H represents center to center height of column.
Figure 04B elaborates cross section of figure 04A. It shows the plan of the column section. It contains further details of longitudinal and stirrup bars.
BEAM COLUMN CONNECTION (Figure 12A & 12B)
Figure 22 elaborates the plan of brace level. The level contains beams, columns and corbels. It contains geometry of the structural components at brace level 1, 2, 3, 4.
Design concept of moment resisting connections at beam-column connections – Transfer of bending and torsional moments
Moment resisting frames and cores incorporating precast elements (beam and column connection) are used to resist horizontal wind or seismic loading. Connections are placed in critical regions and the approach is to use strong connections possessing stiffness, strength and ductility approaching that of cast-in-situ construction and which are easy to construct.
Moment resisting connections have been used primarily to –
• Stabilize and increase stiffness of portal and skeletal frames
• Reduce the depth of flexural frame members
• Distribute second order moments in to beams and slabs, and hence reduce column moments
• Improve the resistance to progressive collapse
The column contain corbel. Figure 13A contains the geometric details of column and corbels. It also has details of loop bars. The cross section of the column plan is given in figure 13 B.
Figure 14A denotes the plan of beam it contains reinforcement and geometrical details of beam.
Beams have been casted using standard reinforcement in the middle while at both the ends extra reinforcement has been provided to achieve better beam-column connection. Columns have been casted with Corbel (with pocket; refer Figure 6B) at the top to provide initial support to beam and to constrain lateral movement of beam. As was the case with column to column connection for beam to column connection also the same block B would be the jointing element. Beam and block A connection has been done using interlocking loops each from beam and block A (refer Figure 14A & 14B). Two steel loops from beam are placed between two loops of block followed by two from beam and they are alternately interlocked with more such loops as can be seen in Figure 14A. The jointing is done using same concreting as the beams and columns with added hardener for quick strengthening.
Figure 06A shows design of corbel which is an intrinsic part of the column while casting. The term 'corbel' refers to a member that projects out from a column and acts as a type of bracket to carry weight imposed by beam. Corbels are built into column to a depth that allows the pressure on the embedded portion to counteract the load on the exposed portion. Based on the location of the column different no. corbels (two, three or four) are casted at the column end. Figure 06B shows the reinforcement details of the corbel
Corbels are mainly used for the following purpose –
• To provide the initial support to beam before the concreting of beam-column joint
• To resist hogging movements by providing fixity to the column near the beam
• To optimize construction time by removing the use of shuttering
• Pocket in the corbel helps in providing extra rigidity
Further the block A and block B connections are as per figure 07. It contains the connection details and dowel tube details of the connection.
The reinforcement detailing of Beams B1 is given in figure 15. It is noticed that there is cast-in-situ casting between block A and beam. The cross sections of beam are given in figure 16A and figure 16B. Figure 16 A shows the cross section of beam from middle part. Figure 16 B shows the cross section of beam near the column.
The reinforcement detailing of Beams B2 which is situated in deck level is given in figure 17. It is similar to figure 15 but reduced level is different. The cross sections of beam are given in figure 18A and figure 18B. Figure 18 A shows the cross section of beam from middle part. Figure 18 B shows the cross section of beam near the column. Figure 18A and 18B contains the connection between deck and beam.
The reinforcement detailing of Beams B3 cantilever which is situated in deck level is given in figure 19A. The cross section of beam is given in figure 19B. Figure 19 B shows the cross section of beam near the column. 19B contains the connection between deck and beam.
Figure 29 represents the reinforcement details of corner of column. Two links are properly jointed between two beams to ensure connectivity between beams.
DECK LEVEL DESIGN
Figure 23 elaborates the plan of brace level. The level contains beams, columns and corbels. It contains geometry of the structural components at deck level
.
Beams at the deck level are designed with grooves on one side and steel bar protruding out from the groove side (Figure 27B). Deck level panels are placed over the groove such that steel bar protruding out from beam is above it. Deck level panel arrangement can be seen in the Figure 25.This arrangement is to prevent any kind of
directional forces due to panel arrangement. Deck level panels have lattice girder (chair link reinforcement) with top of the chair link protruding out of the panel surface towards the inside of the tank side. L shape steel bar is kept at the sides of the panels (between the two panels). The gap between the two panels is filled with cement & sand mortar with epoxy (Figure 27A).
The wall panels goes one over the other and the first one (bottommost) is fitted in the deck level beam’s top groove and between the two columns (refer Figure 24). One wall panel goes in the groove of the other one and a protruding steel bar from the lower panel goes in the drilled hole of the above panel as shown in the Figure 28. 5mm thick rubber sheet is used between the two panels to seal the joint thoroughly. Along the horizontal line of the panel on the water side of the panel steel bars are bent towards the neighboring panel and concreting of the joint with reinforcement from the bent bars using shuttering. Towards the vertical end the wall panel goes in the groove of the column as can be seen in the Figure 29wherein the gap is sealed using 5mm thick rubber sheet and the joint is sealed using silicon. The panels on two sides of the corner column from the water side are interlocked using S shaped steel bars which are concreted to create vertical haunch between column and panel which makes the corner water proofing better.
Panels at the top of the tank are arranged as shown in the Figure 34and the gap between the panels is filled with cement & sand mortar with epoxy. Provision for ventilation and manhole are provided as can be seen in the figure. Steel mesh is welded in ventilator which is then made mosquito proof using stainless steel mesh.
FLOOR TO FLOOR CONNECTIONS – CAST-IN-SITU TOPPING
Figure 26, 27A & 27B shows the details of a roof made of precast elements interconnected by a concrete topping cast over their upper surface. The concrete topping, with its reinforcing steel mesh, provides a monolithic continuity to the floor that involves also the precast elements if properly connected to it. The diaphragm action for the in plane transmission of the horizontal forces to the bracing vertical elements of the structure can be allotted entirely to the topping. Unless greater dimensions are defined from design, for its structural functions the concrete topping shall have a minimum
thickness related also to the maximum aggregate size of the concrete and to overlapped reinforcing steel meshes, such as tmin= 2,4dg >=60mm
Interface shear strength of the connection between the precast element and the topping under seismic action is good enough to prevent differential deflections neglecting the friction contribution due to gravity loads.
Transverse vertical shear at the joint between adjacent floor elements is diverted into the topping. For the good behavior of the connection, proper steel links crossing the interface shall ensure, with adequate anchorages, an effective tension tie between the two parts.
As case be seen in Figure 27B the top of the chair links (which are along the width of the panel) of the deck panels are connected together with steel bar which is inserted in the drilled hole in the deck level beam. At the joint between two panels protruding steel bar from one panel is bent over the other one and similarly steel bar from the second panel is bent over the first one as can be seen in the Figure 27A. From the beams steel bars are protruding out coming over the deck panels. Now the concreting is done over the upper surface (screeding) of panel providing a monolithic continuity to the floor.
DETAILS AT CONTAINER ROOM
Figure 31 shows the column beam plan of container room. It comprises the geometrical details of columns and beams.
DETAILS AT ROOF LEVEL
The reinforcement detailing of Beams B4 which is situated in roof level is given in figure 20. The cross sections of beam are given in figure 21A and figure 21B. Figure 21A shows the cross section of beam from middle part. Figure 21B shows the cross section of beam near the column. Figure 21A and 21B contains the connection between roof and beam.
Figure 30 denotes how wall would be fixed. Further it comprises the various reinforcement details.
Reinforcement details of slab are given in figure 32. It shows the spacing of bars.
Figure 33A represents the cross section of roof slab. It provides the detail of reinforcements and joints between the two slabs. Figure 33 B is cross section of roof slab.
Figure 35 shows the steel wire mesh of ventilator. It can be seen that these are welded mesh and it is mosquito proof mesh.
STAIRCASE DESIGN
Stairs are casted with standard reinforcements as can be seen in the Figure 38.End part of the stair is kept on the stair side of the block A (Figure 39) for landing on corner column which has provision for it. The two drilled holes in the stair end and partial drill hole in block A part below it are matched and then reinforced with steel bars and filled with mortar and sealed (refer Figure 40A & 40B).
The landing platform for the stairs at the middle column is precasted in the column with design as shown in the Figures 43 &43.The middle column is precasted along with beam structure protruding out with small slab structure on both sides (on the lower side of the beam) such that when ends of the stairs are kept over it then it becomes a level platform. Pockets at the end of the stair and in the side part of protruding beam are matched and steel bar is placed and sealed as can be seen in the Figure 41B.
Figure 36 represents the plan of staircase arrangements. It can be seen that the reduced level of all landings are provided. Cross section of staircase is given in figure 37 at 1 grid there are three landings. Reinforcement details of the staircase flight is given in figure 38. The reinforcement details of landing situated in corner is provided in figure 40A and 40B. This figures show the cross section of the landings.
Figure 41A and 41B represents the fixation of landing to column. It provides information about reinforcement. Figure 42 Shows the information of landing beam reinforcement connected with block B.
Figure 43 shows the cross section of these landing beam.
Complete design analysis with all the theoretical references for a 150 KL, 16 M staging precast water tank is provided in Annexure A below. Similar concept would be applicable for different capacity and different staging water tanks.
All the precast elements discussed above would be casted using especially prepared moulds. For every type of precast element a different mould would be prepared which would produce accurate precast elements. The precast concrete structure’s finishing would depend on the quality of moulds & shuttering oil used and proper vibrations during the casting process which is typical for any concrete structures.
The advantage of precast OHT is its inherent time saving feature. The precast technology in OHT will help us erect tanks in much shorter span of time than cast-in-situ. This technology helps in significant cost savings realized through areas such as – expedited construction, reduced time on site, reduced site defects, minimized finance cost resulting from reduced build time, propping & scaffolding costs are reduced and environment wise it’s a green construction technology (it reduces air pollution, noise and debris on site). It requires less labour, equipments and material reducing site congestion. This technology will allow increased accuracy and consistent placement of reinforcement when compared to in-situ construction. Any waste materials are more easily recycled since production is happening at one location and site waste is also less since only finished elements are transported to the construction site.
The drawings and the forgoing description give examples of embodiments. Those skilled in structural engineering will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, orders of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts necessarily need to be performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of
embodiments is by no means limited by these specific examples. Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible. The scope of embodiments is at least as broad as given by the following claims.
Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any component(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature or component of any or all the claims.

I claim:

1. An overhead tank (OHT) comprising:
- beams
- columns
- wall panels
- OHT foundation,
- all types of jointing
- tank floor screeding
- leak-proofing of joints between panels
characterized in that the overhead water tanks are constructed fast using precast technology.
2. An overhead tank (OHT) as claimed in claim 1 wherein concrete elements of the structure would be casted at factory and would be assembled using specific types of joints and steel structures at the overhead tank location.
3. An overhead tank (OHT) as claimed in claim 1 wherein the construction of all the beams, columns, wall panels is being done at precast factory.
4. An overhead tank (OHT) as claimed in claim 1 wherein OHT foundation, all types of jointing, tank floor screeding, leak-proofing of joints between panels and all other joints would be done cast-in-situ.
5. An overhead tank (OHT) as claimed in claim 1 wherein complete base is laid with PCC.
6. An overhead tank (OHT) as claimed in claim 1 wherein the top of the column are casted along with corbels (two, three or four) as per their strategic location.
7. An overhead tank (OHT) as claimed in claim 1 wherein column is connected to another column using dowel tube connection.
8. An overhead tank (OHT) as claimed in claim 1 wherein 5mm thick rubber sheet is used between the two panels to seal the joint thoroughly.
9. An overhead tank (OHT) as claimed in claim 1 wherein unique concrete precast block design ensures fully moment resistant joint between two columns.
10. An overhead tank (OHT) as claimed in claim 1 wherein unique concrete precast block design ensures fully moment resistant joint between column and beam.
11. An overhead tank (OHT) as claimed in claim 1 wherein unique concrete precast block ensures fully moment resistant joint between column, beam and cantilever to support stairs.
12. An overhead tank (OHT) as claimed in claim 1 wherein unique concrete precast block ensures fully moment resistant joint between column, beam and cantilever to support pathway at the top .
13. An overhead tank (OHT) as claimed in claim 1 wherein corbel design ensures full support to beam’s dead load even before jointing.
14. An overhead tank (OHT) as claimed in claim 1 wherein precast walkway slab at tank’s bottom slab level with cantilever is designed in such a way that centre of mass of the component lies on top of beam surface to ensure no toppling of the component.
15. An overhead tank (OHT) as claimed in claim 1 wherein skidding with shear reinforcement on deck level panels ensures no differential deflection between two different slabs due to different load between different slabs.
16. An overhead tank (OHT) as claimed in claim 1 wherein the design ensures desired safety of the structure under standard wind load and earthquake load.