WO2007000561A1

WO2007000561A1 - Section coupling for piling work

Info

Publication number: WO2007000561A1
Application number: PCT/GB2005/002541
Authority: WO
Inventors: Ka Lok Ng
Original assignee: Ho, Jadeson, Cing, Bunn
Priority date: 2005-06-28
Filing date: 2005-06-28
Publication date: 2007-01-04

Abstract

A new section coupling is for use by vibratory, oscillatory and rotatory driving in bored pile construction. It includes adapted ends with inclined surfaces and a bolting system comprising in male section (2) a row of features with reduced thickness (22) and bolt holes (11) (18) and in the female section (1) a row of holes (31) to match for tightening. A set of male supports (7) and female supports (5) are adapted for fitting into the features of reduced thickness and filling the holes (31). All the bolts have counter threads and an overhang at bolt heads for adaptation of a locking device attached to it; all the bolts are restrained by keying the locking device with a spring feature and the overhang. A tool is used to press and un-press the spring features to lock and unlock the bolt. The good fit at interfaces allow transferring of longitudinal force without an elastomeric isolator at interface.

Description

Section Coupling for Piling Work

Technical Field

[1] The invention relates to a joint for coupling steel sections, which is for quick connecting section segments, to facilitate driving it into ground by vibration for excavating and concreting within the segments to form concrete pile, and for quick disconnecting the section segments after withdrawing the section segments from ground when concreting.

Background Art

[2] Such coupling for segments is well known in piling industry for connecting and disconnecting an opened end steel pipe of diameter ranges from 1.2m to 3.0m to facilitate boring to form circular shaped concrete pile but their uses are all limited to either use of an oscillatory method or a rotatory method to drive the pipe segments into ground. Such driving methods are non-percussive in nature and require a crawler crane attached with it at the front two strong hydraulic movable arms and a ring shaped collar for embracing the body of pipe and oscillating it, or require a steel frame attached to it a hydraulic rotatable ring shaped collar and movable arms at four corners embracing the body of pipe and rotating it. The oscillation or rotation of pipe enables the soil surrounding the pipe is loosen such that the crawler crane or the rotator can force the pipe into ground by the arms and the collar at a small amount of penetration at a time.

[3] Other than such oscillatory and rotatory methods, there are two alternative methods also well known for driving an opened end section into ground and they are the vibratory and percussive methods. The vibratory method is a comparatively more economic method to drive an opened end section into ground because it does not require any hydraulic force to drive the section into ground but instead it is by its own weight. The percussive method is comparatively a less common method to be used in today's city because the method would cause serious noise and therefore can only be used when environment allows. Although the vibratory method of driving is well known, yet so far to this date there is no such connecting joint for coupling section segments in the market for the use of vibratory method of driving.

[4] It has been known that vibratory driving occurs relatively easy in non-displacement piles such as sheet piling, H-beam, and open-end pile. This is due to in granular soil the vertical vibration of pile disturbs or liquefies' the surrounding soil and causes the soil particles to lose their friction grip on the pile. Therefore the pile can move downward under its own weight plus the weight of the vibratory hammer. In cohesive soil such as clay, the vibration will shear the soil from pile adhesion and allow the pile to move downward.

[5] Under such circumstance in granular soil, there occurs a transition from a gel to a sol in soil, which after a certain time, is again converted to a gel again. Amplitude of vibration at least 6 mm at pile and soil interface is usually considered the minimum to cause enough soil disturbances to achieve pile movement. At low vibration amplitude, the displacement of soil with respect to the side surface of the pile being inserted does not exceed the limit of elastic deformation of soil and the pile is not sunk into the ground. As the amplitude of vibrations increases, the residual deformation of soil occurs and the pile begins to slip relative to the soil and it is sunk into the ground.

[6] In cohesive soil, vibratory driving becomes less effective and the vibration must shear the soil-to-pile adhesion in order to allow the pile to move downward. Also an amplitude of vibration at the side surface of pile at least 6 mm is usually considered the minimum to cause enough relative movement to shear the soil away from the pile. However in cohesive soil increasing the amplitude of vibration would aid the pile sinking considerably. The reason for this is related to the toe resistance. The vibrator will resort to a chopping mode of operation, in this case by picking up the entire system and forcing it down onto the toe by the vibratory cycle. This in effect makes the entire pile an impact ram and therefore the system amplitude becomes very important as a stroke with an impact hammer. Higher the system amplitudes allow higher velocities and make the impact more effective but heavier the pile can also cause less will be the amplitude in result. The impact force whch is the kinetic energy of the pile at the instant before it contacts the soil is crucial. This kinetic energy is equal to the weight of the pile multiplied by the distance through which it falls. The soil must absorb this kinetic energy to bring the object to rest after impact. And if the impact force exceeds the soil may absorb, the pile will sink. In Shock Theory, the pile will be subjected to shocking stresses by a layer of soil at toe treated as an isolator to underlying harder rock during vibration. Disclosure of Invention

Technical Problem

[7] As such for designing a new pile connection for the vibratory method of driving, the type of forces will act onto the invention are illustrated as below.

[8] Vibration to a pile is usually created by a vibrator when rotating eccentric weights in a gear case powered by a hydraulic motor. Only vertical vibration is created in the gear case as the paired eccentrics, which are connected with gears to maintain synchronization, cancel horizontal vibration.

[9] Engine Power (kW) is one of the key factors which affects the vibrator performance to overcome the skin friction between pile and soil.

[10] Eccentric Moment (kgm), is another key factor to affect, which is the total eccentric weight multiplied by the eccentric distance. The eccentric moment must be sufficient to create sufficient amplitude to exceed the elastic range of soil for a pile to penetrate into ground. Amplitude (mm) is the vertical travel of pile per vibration which is equal to eccentric moment multiplied by 2 and divided by vibrating weight. Frequency (vpm) is the speed of rotating eccentrics and it is also the vibration per minute of vibrator and pile. 1600 vpm is generally considered most efficient.

[11] Suspended Weight (kg) is the total weight of vibrator including gear case, suppressor, clamp, half the weight of the hydraulic hoses and any bias weight or all other additions should be included.

[12] Non- Vibratory Weight (kg) is the weight of the non-vibrating parts of the vibrator which is suppressor + typically half the weight of elastomers and includes any added extra (bias) weight to it. More non-vibratory weight will reduces vibration to crane and the weight is usually handled by crane.

[13] Vibratory Weight (kg) is the suspended weight minus the non-vibratory weight, clamp weight, pile weight, plus weight of soil sticking on pile.

[14] Clamp force (kN) is the hydraulic clamping force provided by clamp(s) to vibrate the pile.

[15] Centrifugal Force/Dynamic Force (kN) is the force generated by rotating eccentrics.

A small increase in speed could cause large increase in centrifugal force in result but however it would only cause little increase in productive capability. Centrifugal force (kN) is equal to eccentric moment (kgm) multiplied by square root of frequency (radian) and divided by 1,000.

[16] An example of a vibrator, Clamp and Power Unit may generate the following forces

(eccentric moment 260.4 kgm, frequency of vibration 1500 vpm, centrifugal force 6424 kN, amplitude 37 mm, maximum line pull 4004 kN, suspended weight without clamp and hose 31681 kg, non-vibrating weight 9434 kg, hydraulic hose weight (say 46m) 2177 kg, clamp force 4448 kN, weight 22487 kg, engine power 783 kW, operating speed 2100 vpm).

[17] An object of this invention is to provide a section coupling and its fixings which must be of sufficient strength to resist various dynamic and chopping forces due to vibration at ground and maintain sufficient amplitude at pile vibration to cause the soil adjacent to pile to liquefy. Its components are required of sufficient wearing resistance to against rubbing and collision when vibrating at high frequency. Use of damper may reduce the damage due to rubbing and collision mechanism but in result the energy of vibration will scatter and lost to cause efficiency of penetration is reduced. The invention is required to avoid high residual stress at its parts and at welds to control indenting and crack propagation within the connection. The invention must be specially robust and not be any loosen due to vibration particularly when punching through the ground.

[18] Yet the invention must be able to be used by conventional methods of pile installation such oscillatory and rotatory methods and easy to install.

Technical Solution

[19] Accordingly, this invention provides a section coupling including adapted ends comprise a male section and a female section both having inclined contact surfaces for coupling in order to resist the chopping force and part of the dynamic forces by longitudinal compression at the sections, together with a bolting system which is adapted for holding and securing the coupled sections for resisting part of the various dynamic forces during vibration by the shear and compression capacity of bolts. The said system comprising in the male section a row of features with reduced thickness and bolt holes along the periphery; and in the female section a row of holes to match with the features with reduced thickness for tightening the coupled sections with a set of supports and bolts. The said feature with reduced thickness at the male section is with tapered edges and is with a group of one bolt hole at centre of the feature and few bolt holes outside the feature. To secure the coupled sections, a male support which is with tapered edges and is adapted for fitting into the sides of the feature with reduced thickness at the male section, is fixed to the male section at locations of the feature with reduced thickness to resist the various dynamic forces by its shear capacity. The male support is with tapered edge for assurance of no tolerance of gap at interface between the feature with reduced thickness and the male support to avoid rubbing and collision when vibration. The male support is with a reduced section at top and a bolt hole at centre attached with a spring feature for a bolt to tight the male support in position by compression and the bolt is restrained from loose by the spring feature. To work with the male support, a female support is fixed into a gap between the male support and the female section to restrain the male support from bending. The feniale support is also adapted with tapered edges for assurance of no tolerance of gap at interface between the male support and the female section to avoid rubbing and collision when vibration. There is a thin elastomeric isolator at the external edge of the female support in order to allow for a minor tolerance of workmanship when coupling the sections together if necessary. However for perfect workmanship, the elastomeric isolator can be eliminated for maximum amplitude at pile vibration and elimination of rubbing and collision during vibration. The female support has two reduced sections and each is with two bolt holes and each bolt hole is with a spring feature attached to it. AU the bolts have bolt heads with counter threads which is opposite to the threads direction at the shaft for adaptation of a locking device attached to it in order to suit for the vibratory method of pile driving. The locking device comprises also counter threads internally and externally and a drop section at bottom. In result, all the bolts can be restrained from turning out by keying the locking device with the spring feature and by stopping the locking device to lift up with an overhang at bolt head. To lock or unlock the bolt, a locking and unlocking tool is adapted for screwing through the external face of the locking device into the reduced section of the male support or the female support. The tool is to press or un-press the spring feature such that to bring the locking device's drop section to be locked by the spring feature or to be un-locked by out of it. The locking and unlocking tool can turn with the locking device together by inserting a pin at a combined hole at the combined sections of two. Advantageous Effects

[20] The invention is possible to cut the piling time of vibratory pile installation method due to eliminating the on-site splicing, cutting, and welding off main sections and addons will be obsoleted.

[21] In additional to [20], the invention results an increased versatility and utilization degree of the portable vibrator for pile driving. This can replace the use of conventional massive sized oscillator and rotator and therefore can eliminate the space and mobility restraints to the sequence of piles installation caused by the oscillator and rotator. This in result allows greater number of piles to be drivable per unit area at a time.

[22] The invention results a promotion of the vibration technology and its application in the foundation industry could make bored piles simpler and faster to be installed in both a single pile aspect by [20] and in a group of piles aspect by [21]. This in result the bored piles are very much economical to be installed in future.

[23] Furthermore the invention can encourage construction of non-circular geometries of shape at pile for a better suit for the pile direction of resistance to the load. This is because the conventional construction method which requires rotating the pile segments at ground by oscillator and rotator in order to sink the pile will be obsoleted. For an example, the invention can be adapted for a rectangular profile at section such that for connecting rectangular steel segments for construction of a rectangular shaped barrette. At present the construction of barrette which requires a specialized contractor to construct and using a special soil balancing fluid, bentonite, to stabilize the trench from collapsing during excavation.

[24] The invention results a promotion of using steel segments for construction of other types of foundation could make other types of foundation simpler, faster and more economical to be installed in future due to [23].

Description of Drawings

[25] A preferred embodiment of the invention will now be described with reference to the accompanying drawing in which:

[26] FIGURE 1 shows a front view of the coupled male and female sections and the being coupled sections of a circular pipe;

[27] FIGURE 2 shows a vertical cross section of the coupled male and female sections;

[28] FIGURE 3 shows a vertical cross section of the fixing;

[29] FIGURE 4 shows a horizontal cross section of the fixing;

[30] FIGURE 5 shows a front view of the fixing;

[31] FIGURE 6 shows a perspective view of a locking and unlocking tool with counter threads;

[32] FIGURE 7 shows a top view of the locking and unlocking tool.

[33] FIGURE 8 shows a perspective view of the locking device with counter threads;

[34] FIGURE 9 shows a top view of the locking device; [35] FIGURE 10 shows a perspective view of the bolt with counter threads and overhang at the bolt head;

[36] FIGURE 11 shows a top view of the bolt;

[37] FIGURE 12 shows a perspective view of the spring feature outside the bolt head;

[38] FIGURE 13 shows a top view of the spring feature;

[39] FIGURE 14 shows a back view of the spring feature;

[40] FIGURE 15 shows a top view of the split washer;

[41] FIGURE 16 shows a usual spring washer under the bolt head;

[42] FIGURE 17 shows the fixing of the coupled sections by spacers 47, alignment nods

46, alignment rods 38 and alignment bolts 44.

[43] A second preferred embodiment of the invention will now be described with reference to the accompanying drawing in which:

[44] FIGURE 18 shows a front view of the coupled male and female sections of rectangular in shape;

[45] A third preferred embodiment of the invention will now be described wth reference to the accompanying drawings in which:

[46] FIGURE 19 shows a front view of the coupled male and female sections of sheet piles;

[47] FIGURE 20 shows a horizontal cross section of sheet piles.

Best Mode

[48] One example of the present invention can be utilized is for connecting steel pipes for to be driven by vibration into ground such that it facilitates excavation within pipes and afterward disconnecting pipes when withdrawn from ground to facilitate concreting within the excavated hole at ground to form concrete pile will be described with reference to a drawing as follows:

[49] As shown in Figure 1, the coupled male (2) and female (1) sections have a series of fixings comprise at the male section (2) the features of reduced thickness (22) and holes (11) (18), and at the female section (1) holes (31) and the male supports (7) and the female supports (5) and the bolts (8) (15) at the female (1) section. In the female (1) section a row of holes (31) to match with the row of features of reduced thickness (22) and the bolt holes (11) (18) and tightening with a set of supports (5) (7) and bolts (8) (15); each feature with reduced thickness (22) at the male section is of tapered edges (33) with a group of one bolt hole (11) at the centre of the feature (22) and few bolt holes (18) outside the feature (6). The bolts (8) (15) may be of difference sizes, which for an example of diameters 30mm and 20mm respectively for a pipe of 2000mm diameter.

[50] Figure 2 shows the male (2) and female (1) sections both have an inclined contact surface for coupling. They are tightened with the male supports (7), the female supports (5) and the bolts (8). The bolts (15) have not been shown in a vertical cross section through the centre of fixing as in Figure 2 but are shown in a horizontal cross section of the fixing in Figure 4. The rubber gaskets (3) (4) are positioned at each end of the sections (2) (1) respectively so that the coupled sections (1) (2) are watertight. For a proper force transferring within the fixing, the contact surfaces are only at interfaces (33) (34) and (32) while the other surfaces are with gap (42) at the interfaces and are not touching.

[51] Figure 3 is an expanded detail of Figure 2 which shows the male support (7) is inserted into the feature with reduced thickness (22) of the male (2) section and tightened by the bolt (8) with the locking device (9) which keys with the spring feature (10) at the reduced section (35) of the male support (7). It also shows the female support (5) is inserted into the gap between the male support (7) and the hole (31) of female (1) section with an elastomeric isolator (45) for a minor adjustment of alignment at the edge of hole (33) at the female (1) section if necessary.

[52] Figure 4 shows the male support (7) and female support (5) are tightened by the bolts (8) (15) with usual spring washers (26) (27) underneath. The locking devices (9) (16) are restrained from rotation by the drop sections (14) (21) which key with the spring features (10) (17) and restrained from lifting by the overhang at bolt heads (48). The bolt heads (8) (15) and locking devices (9) (16) are with counter threads which are in opposite direction to the threads at bolt shaft such that the locking devices (9) (16) will relative to the bolt head (8) (15) move upward when the bolts are unscrewing upward and vise versa. The overhang at bolt heads (48) stop the relative lifting of the locking devices (9) (16) stop the turning out of the bolt (8) (15) in result. The size of drop sections (14) (21) may be of difference size, which for an example of width 20mm at male support (7) and 10mm at female support (5) for a M30 and M20 bolts respectively. The total thickness of the coupled sections at the connection is about 90 mm.

[53] The size of holes (12) (19) at the male support (7) and the female support (5) are larger than the size of bolts (8) (15) for no transferring of shear force to the bolts (8) (15) from the male (2) section to the female (1) section and vise versa. They may be for an example of size larger by 4 mm. The holes (12) (19) are threaded such that they are also used for easing un-tightening the male support (7) and the female support (5) from the male (2) section by screwing an equivalent bolt into the holes (12) (19).

[54] As shown in Figure 5, the female support (5) is restrained from rotating by the series of bolts (15) and the male support (7) is by keying a support (37) with the reduced section (36) of the female support (5) .

[55] As shown in figure 6, which is a perspective view of the locking and unlocking tool

(28) shows counter threads at the internal face and at top there are two slots (30) for inserting a turning bar to turn the locking and unlocking tool (28). The bottom of slots (30) may match with the top of the locking device (9) (16) as the bottom of drop section (14) (21) at the locking device (9) (16) matches with the bottom of locking and unlocking tool (28). The figure (7) shows its top view. [56] Figures 8 shows a front view of the locking device (9) (16) which has a drop section (14) (21) at the bottom and counter threads externally and internally. As shown in figure 9 a half circle recess (24) (25) at the locking device (9) (16) matches with that half circle recess (29) at the locking and unlocking tool (28) such that they may be combined and perform as a provision for turning the locking device (9) (16) with the locking and unlocking tool (28) if inserting a pin to the combined hole (24) (29).

[57] Figure 10 shows a front view of the bolt (8) (15) which has counter threads and an overhang (48) at the bolt head. As shown in figure 11, it is a top view of the bolt (8) (15).

[58] Figures 12 and 14 show a front view and a back view of the spring feature (10) (17) welded (43) onto the washer (13) (20). The spring feature (10) (17) may be made of spring metal and is with two raised arms. The washers (13) (20) are with drop sections (40) for keying with the split washers (41) (23) welded to the male support (7) and the female support (5). The spring features and washers (13) (20) are welded onto the split washers (41) (23) so that they form parts of the male support (7) and the female support (5). Figure 13 shows a top view of the spring feature (10) (17).

[59] Figure 15 shows a top view of the slit washer for welding to the male and female supports to key with the drop section (40) of the spring feature (13) (20).

[60] Figure 16 shows a usual spring washer to be positioned under the bolt.

[61] Figure 17 shows using the alignment bolts (44) and the alignment rods (38) for aligning the sections (1) (2) when coupling. The alignment rods (38) and the alignment nods (46) are used to align and temporary screw tight the sections together before installing the female support (5). The installation method may require the male (2) section to be hung after inserting into the female (1) section until the male supports (7) are positioned and the spacers (47) are set for the male (2) section to sit onto the spacers (47).

Mode for Invention

[62] A second example according to the present invention will be described with reference to Fig. 18 as follows:

[63] The present invention can be utilized for connecting steel sections of rectangular in shape to be driven by vibration into ground such that it facilitates excavation within the rectangular section and afterward disconnecting pipes when withdrawn from ground to facilitate concreting within the excavated hole at ground to form concrete barrette pile.

[64] This example describes an example of another shape of section which may be applied and where the detail of features of the example 1 is applied to this example. As shown in Figure 18, the coupled male (2) and female (1) section have a series of fixings comprise the features of reduced thickness (22) and holes (11) (18) at the male (2) section as shown in example 1, and holes (31) and the male supports (7) and the female supports (5) and the bolts (8) (15) at the female (1) section. In the female (1) section a row of holes (31) to match with the row of features of reduced thickness (22) and the bolt holes (11) (18) and tightening with a set of supports (5) (7) and bolts (8) (15); each feature with reduced thickness (22) at the male section is of tapered edges (33) with a group of one bolt hole (11) at the centre of the feature (22) and few bolt holes (18) outside the feature (6). The bolts (8) (15) may be of difference sizes, which for an example of diameters 30mm and 20mm respectively for a rectangular shape of 2000mm linear dimension. The total thickness of the coupled sections at the connection is about 90 mm.

Mode for Invention

[65] A third example according to the present invention will be described with reference to Fig. 19 and 20 as follows:

[66] The present invention can be utilized for connecting steel sections of sheet piles to be driven by vibration into ground to form sheet pile wall such that it facilitates excavation within the enclosed area of the sheet pile wall for construction works to be executed and afterward disconnecting sheet piles when withdrawn from ground after completion of the construction works and the area has been backfilled with soil.

[67] This example describes an example of another shape of section which may be applied and where the detail of features of the example 1 is applied to this example. As shown in Figure 19, the coupled male (2) and female (1) section have a series of fixings comprise the features of reduced thickness (22) and holes (11) (18) at the male (2) section as shown in example 1, and holes (31) and the male supports (7) and the female supports (5) and the bolts (8) (15) at the female (1) section. In the female (1) section a row of holes (31) to match with the row of features of reduced thickness (22) and the bolt holes (11) (18) and tightening with a set of supports (5) (7) and bolts (8) (15); each feature with reduced thickness (22) at the male section is of tapered edges (33) with a group of one bolt hole (11) at the centre of the feature (22) and few bolt holes (18) outside the feature (6). The bolts (8) (15) may be of difference sizes, which for an example of diameters 16mm and 12mm respectively. The alignment of fixings for sheet pile wall is staggered such that a provision of bending stiffness at the connection point is provided by adjacent sections at the connection point. The total thickness of the coupled sections at the connection is about 70 mm.

Industrial Applicability

[68] According to the present invention, an application of the invention to the construction industry for bored pile foundation is appropriate. The coupling sections have adapted ends and fixings which have eliminated possibility of rubbing, collision and therefore more suitable for vibratory method of pile installation to speed up the installation of pile, or by conventional oscillating and rotating more suitable for overcoming underground obstruction due to stronger connection at pipe sections and more effective transfer of force due to no tolerance of space at interface contacts. Thus, this invention makes bored piles simpler, faster and more economical to be installed in future. [69] Further, the present invention can be applied to construction industry for barrette foundation. According to this invention, it results a promotion of the vibration technology and its application in the foundation industry which results an elimination of rotation of steel sections at ground in order to sink the steel sections into ground. Thus, this invention makes barrette piles simpler, faster, more economical, and more environmentally friendly to be installed in future.

[70] Furthermore, the present invention can be applied to construction industry for sheet piling works. The invention is possible to cut the piling time of sheet pile installation due to eliminating the on-site splicing, cutting, and welding off main sections and addons will be obsoleted.

[71] Even more, this invention is also applicable for the oil extraction industry where steel pipes can be quickly connected and driven into the ground or seabed by vibrator for extraction of oil. The invention is possible to cut the pipe installation due to eliminating the on-site splicing, cutting, and welding off main sections and add-ons will be obsoleted.

Sequence List Text

[72] Not Applied

Claims

[1] A section coupling including adapted ends comprise a male section and a female section both having inclined contact surfaces for coupling, together with a bolting system which is adapted for holding and securing the coupled sections; said system comprising in the male section a row of features with reduced thickness and bolt holes along the periphery and in the female section a row of holes to match for tightening with a set of supports and bolts; each feature with reduced thickness at the male section is of tapered edges with a group of one bolt hole at centre of the feature and few bolt holes outside the feature; a male support is of tapered edges and is adapted for fitting into the sides of the feature with reduced thickness at the male section, with a reduced section at top and a bolt hole at centre attached with a spring feature with raised arms; a female support is adapted with tapered edges with a thin elastomeric isolator at the external edge and for filling the hole at the female section after inserting the male support , has reduced sections with bolt holes and spring features attached; all the bolts have counter threads which is at opposite direction to the threads at bolt shaft and an overhang at bolt heads for adaptation of a locking device attached to it; the locking device is with counter threads internally and externally and a drop section at bottom; all the bolts can be restrained from turning out by keying the locking device with the spring feature and by stopping a lifting of the locking device with the overhang at bolt head; a locking and unlocking tool is screwed through the external face of the locking device into the reduced section of the male support and the female support to press and un-press the spring features and bring the locking device's drop section to between the spring feature's raised arms or out of it; the locking and unlocking tool can turn together with the locking device by inserting a pin at a combined hole at the combined sections of two.

[2] A section coupling as claimed in Claim (1) where the elastomeric isolator is for allowance of tolerance at installation and is not required if the fixings are perfectly fit after coupling with the alignment bolts, the alignment rods and the alignment nods.

[3] A section coupling as claimed in Claim (1) where the size of bolts at the female support are smaller than the size of bolt at the male support.

[4] A section coupling as claimed in Claim (1) where the size of holes at the male support and the female support are larger than the size of bolts for no transferring of shear force from the male section to the female section and vise versa to the bolts; they are threaded such that to ease un-tightening the male support and female support from the female section by screwing a bolt into them.

[5] A section coupling as claimed in Claim (1) where the holes at the female support are radial located.

[6] A section coupling as claimed in Claim (1) where the size of locking device matches with the size of the bolts at the female and the male supports; the size of drop sections at the locking device is of difference sizes at the female and the male supports accordingly.

[7] A section coupling as claimed in Claim (1) where the locking device has a drop section at the bottom and counter threads externally and internally; it provides a half circle recess for matching with that half circle recess at the locking and unlocking tool such that they may perform as a provision for turning the locking device with the locking and unlocking tool if inserting a pin to the combined hole.

[8] A section coupling as claimed in Claim (1) where the female support is restrained from rotating during vibration by its own series of bolts, and the male support is by keying a support with the reduced section of the female support.

[9] A section coupling as claimed in Claim (1) where the reduced sections at the male and female supports comprise two-steps which the lower step is to house the bolt head and a spring washer and the higher step is to house the spring feature outside the bolt head.

[10] A section coupling as claimed in Claim (1) where the shape of section can be of circular, rectangular or sheet profile.