A CABLED PIPE RACK

Abstract

A cabled pipe rack is an assembly of structural elements put together to form a robust structural framework to function similar to conventional pipe rack. The invention employs tension cables to support lateral movements of transverse frames along the longitudinal direction. Tension cables are primarily anchored to the main anchoring structures strategically located at both ends of cabled pipe rack assembly. This structural assembly is a zero braced pipe rack completely eliminates pipe clashing issues to any bracing elements. This innovation have taken the structural benefits from a composite column made up of steel and concrete with a fully rigid connection at the base, and a fully welded joint connections of transverse beams and columns. The invention is a unique structural system seen as a suitable substitute to the conventional pipe rack.

Description

FIELD OF INVENTION

This invention relates to a cabled pipe rack which is seen as a solution to resolve current issues surrounding the design, fabrication, and erection of a conventional pipe rack.

BACKGROUND OF THE INVENTION

Steel pipe rack structures are major items in the oil and gas industry, oil refinery, gas plant, liquefied natural gas plant, petrochemical plant, chemical plant, mining processing plant, and power plants. Steel pipe rack structure generally support pipes use to transfer or deliver any liquid, gas, and steam between equipments, storage tanks, utility areas, and flare lines, it also serve as support to power cables trays, instrument cable trays, light mechanical equipment, vessels, and valve access platforms.

A conventional pipe rack is a structural steel framework mostly of multi-level in forms consisting series of transverse steel frames made up of steel H-section columns and transverse I-section beams that run along the length of the pipe system typically spaced at 6.0M intervals. Transverse frames are connected with longitudinal struts to form a 48-meter length of one conventional rack. Industry standard practice has put a 50-meter maximum limit to a one rack length to allow each rack to move independently during thermal expansion and seismic actions. A steel base plate is shop welded to the base of an H-section column, during site erection it is mounted on top of concrete pedestal and directly connected to the pedestal using high strength anchor bolts with thicker base plates. Underside of base plate and the top, of concrete pedestal is serving as the interface point between concrete and steel structures. Steel pipe rack technically requires transversal and longitudinal steel bracings to achieve and maintain lateral stability against lateral forces like wind and seismic loads acting in both directions.

Conventional pipe rack that is commonly used in the industry has not ever been changed nor have improvements ever been introduced until this present time. Conventional pipe rack have lots of pit falls during detailed engineering design, fabrication, and erection phase at the project site that requires significant improvement, or a new invention of pipe rack is significantly necessary to overcome these various issues affecting the integrity of the conventional pipe rack. These pitfalls contribute to delay project delivery and completion. Common cause of delay during engineering phase is when there are clashing problems of pipes and transversal steel bracings. Piping engineers are firmed with their position to install pipes uninterrupted along the pipe way, pipes must be free of clashing to any bracing elements. On the other hand, structural engineers handling the structural analysis firmly insist that pipes to give way if clashing exist because bracing is a major structural element of the pipe rack necessary to maintain lateral stability of the structure which cannot easily be relocated nor be removed unless engineering calculations are satisfied.

If a conventional pipe rack does not have enough transversal bracings, structural engineers are struggling much on dealing with their computer aided load analysis in achieving the lateral stability of the rack within their allowable limit especially in cases where taller racks are to be erected at project locations of high winds and high seismic forces.

Solving tons of clashing issues and technical mismatch during detailed design phase for a particular refinery project is a typical major concern and remain a repeated headache in the industry because structural engineers and piping engineers cannot easily resolve clashing issues, much time are wasted in arguing at the workplace during engineering meetings and model reviews:

Alternative solution which is commonly adopted by structural engineers to solve pipe clashing issues against transversal bracing is by employing an end-moment connection of beam to column joints of transverse frame which is theoretically acceptable if parameters are met. However, to achieve a full end-moment connection in steel construction, if has to be a full welded joint connection of an I-beam to the column which requires massive welding work activities at the project site during erection phase, but this method is heavily opposed by construction team due to lots of constructability issues and entails longer period of delivery.

The industry has tried solution by using an end plate bolted type of connection to eliminate welding work at site, this solution is popularly not accepted by structural engineers because of its infamous assumption that end-plate bolted connection can produce equal capacity to full welded connection. Engineering theories have demonstrated that bolted end-plate moment connection of a beam to a column can produce only a partial capacity of stiffness due to a provision of standard tolerance gap in between joints necessary to ease erection activities. By simply looking at the given details, it appears that assumptions made to load analysis, and erection requirements are not matching technically. Despite of these technical mismatches, industry still adopted this arrangement to avoid massive full welding activities at the site during erection phase that could potentially extend milestones which require extra cost to the project's budget.

Trying further to finding a solution, the industry allows a condition that during erection at the site 90% of the area of bolted end-plates joint connection and the column flange must be in full contact to satisfy the engineering requirement without using an insert plate to fill gap whenever unexpected gap exist between the column flange and the end plate of the main beam for a particular joint. However, this condition again seemed to be frustrating for erection team to achieve because steel components cannot simply be erected if gap exist between joints because it would demand excessive application of tightening force to the bolts which in return becomes highly critical for the bolts of being over-stressed. Cases of over-stressing of bolts and tightening failures are abundance already during erection period at the site and in most cases have caused already to delay erection time and some have resulted to minor accidents.

To prevent over-stressing of bolts particularly in cases where gaps are more than the tolerance limit, a silent concession among construction team is agreed to allow the usage of insert plate to fill gaps, a clear violation of the 90% engineering condition parameters. This inappropriate action among construction team is technically opposed and argued by engineering team as a critical deviation from design specification seriously considered by quality control team as poor quality practice of erecting structural steel leading to a conclusion of a non-conformance behavior by the construction team. In return, construction team defended themselves by pointing back to engineering team as the weakest team in the group by producing poor quality of design drawings that are difficult to construct at the project site resulting to a poor quality of erection. This circus of events have not change and still actively current.

Collaborative solutions made by the industry are helping nothing to clear out multi-level issues and this trend is being carried-over from project to projects within the industry, arguments among the project teams area continuously happening every now and then. The industry has left no choices, the erection activities have to go on as planned to meet the target project delivery. These multi-level issues remain unsolved, a great challenge directed to the field of civil/structural engineering practice globally.

The invention of a cabled pipe rack is seen as a total solution to resolve these multi-level issues; eliminating pipe clashing, minimizing workplace arguments, regaining the integrity of engineering; achieving erection quality and; meeting project delivery. Aside from solving current issues for a conventional pipe rack, the invention seemed to benefit the industry big-time by saving enormous tonnage of steel, man-hours, time table, and money.

BRIEF SUMMARY OF THE INVENTION

The invention is a disclosure of technical solutions to help multi-discipline engineers working in the industry who are continuously facing various technical challenges at their workplace from engineering design phase, shop fabrication, shop welding, and site erection of a conventional pipe rack.

The invention is directed to a cabled pipe rack, an invention of structural framework of pipe rack employing tension cables to support lateral movements of transverse frames along the longitudinal direction, a zero braced pipe rack, completely eliminates pipe clashing issues, resolve technical mismatch and disagreements among members of engineering, construction, and quality control teams.

The invention produces a robust transverse frames which are the main support of the pipe way by employing composite hallow steel section columns poured with concrete. Based on this, a solid concrete column is formed and confined within the hallow steel section column. The solid concrete column is directly attached to the top of concrete pedestal passing through a cut-off hole of the base plate with same diameter of the hallow steel column, starter steel bars with minimum of 1.0 meter in height are planted on the concrete pedestal and also passing through the cut-off hole of the base plate getting into the hallow steel column, this arrangement produces a fully rigid connection at the base when concrete is already cured, if the base has rigid support connection it has the capability to withstand lateral stability. Therefore, vertical bracings at the base level is no longer required thus producing a zero braced pipe way at the ground level. Interestingly, tonnage of steel plates, stiffener plates, and no. of anchor bolts are extremely reduced at the base level alone.

Additional point is that, full stiffness is achieved at the joints of beam and column by employing a cut-off main 1-beam of 600 mm in length fully welded to the composite column through the ring stiffeners placed aligned with beam's flanges at every rack levels, the splicing of the main beam is moved to a safe distance of 600 mm from face of column this safe distance are having reduced internal forces already, any possible gaps can easily be handled by a simple connection design only and site installation becomes simpler, technical issues of bolts overstressing are totally eliminated thus achieving a good erection quality.

The invention claims to have an innovative strategy to move the splicing point away from face of column has resolved the technical mismatch because the invention has employed welded joint connection of beams directly to the face of columns, thus producing a genuine full end-moment connection capacity technically and theoretically matching with the load analysis. Technical issues to the conditional requirement of 90% contact of joint surfaces during erection are no longer applicable. This new arrangement produces a zero braced pipe way at the upper levels of the cabled pipe rack thus totally eliminating chances of clashing. Prior to site delivery, cut-off I-beam is fully welded to a hallow steel column as a fabricated item

During site erection, anchor structures must first to be established, it has to be erected at designated locations and has to be poured with concrete ahead than the frames to give sufficient time of curing, concrete must be cured before any anchoring work are to be carried-out. Prior to erection of frames at site, each frame is assembled by bolting the fabricated items of columns with cut-off I-beam and the main beam together at a leveled lay down position. Boom crane with spreader will be used to lifting the assembled frames in either one whole or by segments into a desired position, temporary guying with turn-buckle attached on both sides of frame will be used to hold during erection to keep erected frames at vertical alignment.

Once all the transverse frames are erected and completely aligned, horizontal tension cables are installed continuously from one end of the anchoring structure all the way to the other end, turn-buckle attached to the cable will be used to fine-tune necessary incremental adjustments to achieve a perfect vertical alignment of the frames. These tension cables will be acting as permanent lateral supports designed to hold minor lateral movements of transverse frames along the longitudinal direction. Anchor structures are obviously located at both ends of pipe rack length playing a primary role to this invention.

By employing composite columns to the structural system, the hallow steel columns are poured with concrete, once curing period of concrete is reached, it produces robust structural framework This robustness are product of composite columns with rigid connections at the base, and with fully stiffened joint connections of columns and beams of the transverse frames. These frames are physically and theoretically proven to be highly resistant to lateral forces in both transversal and longitudinal directions, having these structural benefits, tension cable rods with shackles and turn-buckles are employed innovatively to substitute conventional solid I-beam section popularly used as a longitudinal strut for the conventional pipe rack. This innovative strategy to use tension cable rod as substitute to solid I-beam strut have save tremendously tonnage of structural steel, and time allotted for fabrication, shop welding, and erection. Size and strength of tension cable rod, shackle, turn-buckle, and gusset plates are determined by engineering calculations.

Miscellaneous non-structural components of pipe racks are connected to the main structural system through hook-ups e.g. catwalks, cable trays, stairwell, exit ladders, deflection support of smaller pipes, special pipe support beam along the longitudinal axis when needed only, upward extension of pipe rack to cater supporting frames for multi-level cable trays mounted at the top level can be done by simply using a flange to flange type of column connection. Non-structural hook-up assembly will be developed independently to suit individual project requirements. Development of such could proceed using either conventional or could further employ new innovative approach to form part to this invention as potential future amendments to cater for non-structural items:

The invention is totally new to the industry, a disclosure of technical solutions seen to give more benefits to the industry by saving tonnage of structural steel, time, and money during engineering design phase, shop fabrication phase, and finally to site erection phase.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing cabled pipe rack structural framework with 5 level rack, tension cables are anchored at both ends using Type-1 (Diagonally braced) Anchoring structures located at both ends of one rack length.

FIG. 2 is a perspective view showing cabled pipe rack structural framework with 7 level rack, tension cables are anchored at both ends using Type-2 (Braced-Tower) Anchoring structures located at both ends of one rack length.

FIG. 3 shows cabled pipe rack longitudinal elevation with 5 level rack, tension cables are anchored using Type-1 (Diagonally braced) Anchor structures located at both ends of one rack length.

FIG. 4 shows cabled pipe rack longitudinal elevation with 7 level rack, tension cables are anchored using Type-2 (Braced-Tower) Anchor structures located at both ends of one rack length.

FIG. 5 shows cabled pipe rack transversal section with 5 level rack. The main beam is spliced at 600 mm away from face of column at both ends of beam.

FIG. 6 shows cabled pipe rack transversal section with 7 level rack. The main beam is spliced at 600 mm away from face of column at both ends of beam.

FIG. 7 shows enlarged drawing of Type-1 (Diagonally braced) Anchoring structures.

FIG. 8 shows enlarged drawing of Type-2 (Braced-Tower) Anchoring structures. Braced Tower is primarily used as anchoring structure for most heavily loaded racks with 7 levels and above specially at project locations of high winds and high seismic forces, wherein a diagonally-braced anchor structure can no longer handle.

FIG. 9 shows enlarged drawing of Fully Welded Beam to Column Joint. This drawing illustrates the End Moment Connection at column joint using ring stiffeners of column as receiver of cut-off I-beam.

FIG. 10 shows enlarged drawing of Simple Beam Splice located at minimum distance of 600 mm from face of column. Cut-off beam is fully welded to the column is one fabricated item prior to site delivery.

FIG. 11 shows enlarged drawing of Gusset Plates with slotted holes fully welded to the ring stiffeners of Column to cater tension cables placed at every rack level and between frames all the way to the anchoring structures.

FIG. 12 shows enlarged drawing of Starter Bars planted to the concrete pedestal with minimum height of 1.0 meter passing through the hole of the base plate to allow a solid concrete column thus producing a fully rigid connection at the base using only minimal thickness of base plate, stiffener plates, and reducing the no. of anchor bolts.

FIG. 13 shows typical drawing of longitudinal beam installed at beam level in cases where pipes are coming in and going out from the pipe way would need special support along the longitudinal direction. Connection is a simple pin only.

FIG. 14 shows typical drawing of longitudinal beam installed in-between rack levels in cases where pipes are coming in and going out from the pipe way at any vertical position would need special support along the longitudinal direction. Connection is a simple pin only using a clamp type tied by bolting to the steel columns, a rubber band or equivalent material may be placed in-between to avoid direct, contact of steel surfaces to minimize rust accumulation.

FIG. 15 shows tension cable rod with turnbuckle to serve as plan cross-bracing (see FIG. 15) to resist torsional forces applied at the top flange of main beam due to pipe anchor and friction forces, will be hooked-up to desired location within the rack assembly, detailed design and, pinned type connection will be developed accordingly to suit piping requirement.

FIG. 16 is a temporary guying used during erection of transverse frames anchored to the sides of concrete pedestal along the longitudinal axis

DETAILED DESCRIPTION AND BEST MODE OF IMPLEMENTATION

The invention is directed to rearranging things inside the box. A cabled pipe rack 10 and 10a as shown in FIGS. 1 & 2 will completely function similar to conventional pipe rack but largely of different structural composition, physical appearance and methods of creation.

The invention is an smart assembly of significant structural elements that have put together to form a robust structural framework simply made up of locally available construction materials, like: tubular hallow steel column 11 (circular, square, and rectangular section), a base plate 12 with a cut-off hole with same size and opening of hallow tubular column, a tension cable rod 13 with shackle 14 at one end and, turn buckle at the other end, an I-beam 15, steel bars 16, and a concrete-mixed material. The above composition of materials, the methods injected and collaborative functions of each element forming the structural system has come up to produce a more robust structural framework of pipe rack structure with much lesser amount of steel tonnage involved, much easier to design, fabricate, and erect.

During site erection of the cabled pipe rack, anchor structures must first to be established, it has to be erected at designated locations and has to be poured with concrete ahead than the frames to give sufficient time of curing, concrete must be cured before any anchoring work are carried-out. Prior to erection of frames at site, each frame is assembled by bolting the fabricated items of columns and beams together at a leveled lay down position, assembly could be done either one whole piece if rack is only 3 levels and below, or could be 2 or 3 segments depending on the size or height of transverse frame, cutting point is at splicing point of columns. Boom crane with spreader will be used to lift the assembled frames as a whole or by segment into a desired position, temporary guying with turn-buckle on both sides of frame will be used during erection to keep erected frames at vertical alignment.

Once all the transverse frames for a one rack length are completely erected and aligned, permanent horizontal tension cable rods with turn buckle are installed at every rack levels to interconnect series of transversal frames all the way to the anchoring structures, horizontal tightening of tension cables is determined by engineering calculation designed to stabilize potential lateral movement of transverse frames at maximum load applications. Once frames are fully anchored and inspected, concrete is poured to the hallow steel columns of frames, the procedure of concrete pouring and curing requirement will be developed separately in accordance with industry standards and construction practices.

The structural system of the cabled pipe rack is an assembly of 5 major components to keep the structural, system fully functional. Each component is illustrated below with their respective and collaborative functions that seemed to drive this innovation to be put forward into a real thing. This invention is seen to change the face of oil refinery plants, gas plant, liquefied natural gas plant, petrochemical plant, chemical plant, mining processing plant, power plants, and other similar industrial plants projects.

First Component, (FIGS. 5 & 6)

Transverse Frames, are made-up of:

a) Hallow Steel Section Column with Rigid Fixed Support Connection at the Base—

The invention is associated to a tubular hallow steel section as the most appropriate material to be used as columns to allow a composite column technology to govern. The primary intension of using hallow steel section is to produce a fully rigid connection at the base by simply employing starter bar dowels planted into the concrete pedestal (see FIG. 12) passing through a cut-off hole opening of the base plate all the way into the hallow steel column. An average of 4 nos. of anchor bolts are enough to hold the columns during erection period, once the frames are installed and aligned, concrete will be poured to allow more robust composite column with full rigidity at the base where vertical bracings are no longer required at the ground level thus producing a zero-braced pipe way.

• • The invention of a rigid connection can guarantee to achieve a 100% lateral stability at the base, it produce a genuine rigid base connection of transverse frame requiring only minimal thickness of base plate, minimal stiffener plate, and fewer nos. of anchor bolts. When applied moment forces at the base are large enough, structural engineers would simply use larger diameter of hallow steel column along with the required starter steel bars area calculated to produce a moment capacity more than the applied forces. Additionally, engineering calculation is much simpler to execute, time is much saved at the fabrication shop, and erection work becomes simpler with only 4 nos. of anchor bolts need to be tightened.
  • To keep the composite column to acting as one column, shear connectors are employed to be welded to inside face of hallow column reachable by welding, size and spacing of connectors will be determined by engineering calculation. Provision for the area of steel reinforcement to be spliced to starter bars inside. the steel column is optional, or to be determined by calculation, methods of bar placement to be develop separately in line with the industry practice. Hollow tubular steel column can easily be spliced vertically using flange to flange bolted connections, splicing may vary from same size of columns put on top of the other, or a reducing size of column to be placed at the upper level.

b) Full End-Moment Connections of Beam to Column Joints—(FIG. 9)

This innovation has employed a cut-off I-beam 17 of 600 mm in length to be fully welded directly to the face of column 11. This arrangement has achieved full stiffness at the joints of beam and columns thus producing a fully stiffened transverse frames. through the ring stiffeners placed aligned with beam's flanges at every rack levels, the main beam is spliced at the edge of cut-off beam 17 600 mm from face of column 11 (see FIG. 10) which require a simpler connection design only.

• • Fully welded joint connections of beams and columns produces full end-moment capacity to all the joints of the transverse frames at all levels, which means that provision of vertical bracings at the upper levels of the cabled pipe rack are no longer necessary thus it produce a zero braced pipe way at the upper levels. Prior to site delivery, cut-off I-beam is welded to hallow steel column as a fabricated item.
  • The claimed cabled pipe rack transverse frames will all be erected at site by bolted connections while achieving full moment capacity of joints, with no single welding work to be done at site. Engineering calculation and load analysis is satisfied with no technical mismatch, no deviation and concession to design specification, a 100% full, compliant to engineering requirement and meeting constructability demand.
  • Industry practice permits one conventional pipe rack to have a maximum length of 50 meters to allow thermal expansion during operating condition and to release energy during seismic actions. Interestingly, cabled pipe rack assembly has a potential to span up to 100 meters, because thermal expansion is handled individually by slotted holes within the connection plates on each frame, likewise seismic energy is released straight away within the slotted holes. If 100 meters length is adopted, permanent diagonal guying shall be provided to support to at least 2-frames at equal distance to reduce tension loads at the main anchor points.

Second Component,

Anchor structures 18—are playing as one of the most innovative role to this innovation, this is where all the lateral loads will be neutralized and resisted. Anchor structures are serving as anchor points to all tension cables 13, these structures are strategically located at both ends of every full length of cabled pipe rack assembly. These are categories but not limited to 2-types: Type-1 to cater for. 6-levels pipe racks and below, and Type-2 to cater for 7 levels of pipe racks and above, other types can be developed within the context of type-1 and 2. Anchor structures 18 are designed to withstand longitudinal stability against anchor loads. Anchor structures must first to be established during site erection of the cabled pipe rack, this would need to be erected at designated locations and has be poured with concrete ahead than the frames to give sufficient time of concrete curing. Concrete must be cured prior to any anchoring activities. Engineering calculation will validate the lateral stiffness of the anchor structures for type 1 and 2.

Type-1, Diagonally-braced anchor structures (FIG. 7) 19—are made up of the same design and materials to that of transverse structural steel frame, the assembly is made up of a vertical frame 191 located at the last row and a diagonal frame 192 inclined to outward position with the 0.2 having a common joint at the top edge welded together through a connection plate 193. To complete the anchoring structure, small sized I-beam 194 is installed at every rack level to reinforce the anchoring assembly along the longitudinal axis adopting the same joint connection strategy. Gusset plates 195 with slotted holes to cater pin connection of tension cables are provided at every rack level of the anchoring structure. Assembly and erection strategy is similar to transverse frames.

Type-2, Braced-tower anchor structures (FIG. 8) 20—are made up of the same design and materials to that of transverse main structural steel frame, the composition are made up of the last 2 rows of vertical frames 201, 202, connected together at all sides with small sized I beams 203 to be installed at every level and diagonal cross-bracings 204 using small sized H section to be installed between levels from top of pedestal up to the top level. Beam to column connection to use same full moment connection strategy, cross-bracing to use pinned-type joint connection. Use gusset plates 205 placements similar to type-1. Assembly and erection strategy is similar to transverse frames.

Third Component (FIG. 9),

Tension cable rod with shackle at one end and with turn-buckle at the other end 13 and 14—This component is one of the most dramatic part of the innovation and an eye Catcher to the structural system. The present invention innovates the lateral support using tension cable rods 13 to replace the conventional I-beam sections originally used as longitudinal struts to interconnect series of transverse frames along the longitudinal axis. Firstly, based on actual circumstances, it is evident that when all pipes are completely installed on the pipe rack it basically helps to strengthen the longitudinal axis of the pipe way and its supporting frames against any individual frame movement; Secondly, the interconnection arrangements of various pipes along the pipe way are proven to further reinforce the longitudinal stability of the pipe rack assembly. Thirdly, the invention took the structural benefit from the robustness of transverse frames that require only minimal longitudinal support. These basis are technically satisfied. Size and strength of tension cable material, shackle, turn-buckle, and gusset plates are to be determined by engineering calculation.

During erection of transversal frames guying are temporarily used to keep frames aligned at vertical positions, this can be done by providing one or more circular anchors embedded at the side portion of concrete pedestal 21 (see FIG. 12) to where the erection guying are to be pin-connected using shackle. When all the frames are erected and completely installed at final position, tension cable rods will now be installed horizontally at every rack levels to finally interconnect frames all the way down to the anchoring structures. Each cable length holding the frames is pinned connected into the slotted holes of gusset plates, while at the other end is using turn-buckle to control incremental alignment.

Industry practice permits one conventional pipe rack to have a maximum length of 50 meters to allow thermal expansion during operating condition and to release energy during seismic actions. Interestingly, cabled pipe rack assembly has a potential to span up to 100 meters, because thermal expansion is handled individually by slotted holes within the connection plates on each frame, likewise seismic energy is released straight away within the slotted holes. When 100 meters length is adopted, at least 2-frames at equal distance are supported with diagonal tension guying to reduce tension loads at the main anchor points.

Fourth Component,

Concrete material—is one of a key element used to the structural system that helps to produce a robust solid vertical element. The results show that the confinement effect of concrete within a steel tube section does play a big role in increasing the compressive strengths to almost 60%, thus making 4 composite column a robust vertical element. Concrete is poured to hallow steel columns after all transversal frames are erected, perfectly aligned, vertically stable, and are fully anchored to the anchoring Structures. After the concrete is cured, cabled pipe rack produces a robust transverse frames with full rigid connections at the base of columns, physically and theoretically accepted as highly resistant to lateral forces in both transversal and longitudinal directions. Mixture of concrete, curing requirement, procedure and methods of pouring will be developed accordingly and separately to suit project requirements.

Fifth Component,

Miscellaneous Accessories.—are non-structural components to be developed as a separate hook-up assembly to suit individual project requirement to be connected using pinned type at desired locations during site erection. During design development, the strength of non-structural components will not be calculated, all detailed drawings of miscellaneous components are simply develop using standard drawings accepted by the industry. Extra input loads due to these components are considered in the load analysis of the main rack assembly.

Pipe racks miscellaneous hook-up assembly are listed below:

a). Extension of column at the top portion of racks to cater cable trays to be used for electrical and instruments lines, will be connected through a bolted flange at the top end of column, the receiving flange is already provided by structural assembly ready to received any column extension.
b). Main stairwell, catwalk and cage ladder for operational access, maintenance, and emergency exit, will easily be hooked-up by simple pinned connection to the main rack assembly, detailed design and pined type connection will be developed accordingly to suit project requirement.
c) Platforms for lighter equipments, will be fabricated and hooked-up to desired location within the rack assembly, detailed design and pinned type connection will be developed accordingly to suit mechanical engineer's requirement.
d) Intermediate hook-up support for smaller pipes to support its sagging in-between regular spans, to be fabricated and hooked-up to desire locations within the rack assembly, detailed design and pinned type connection will be developed accordingly to suit project requirement.
e) Longitudinal beam to support pipes coming in and out from the main rack (see FIGS. 13 & 14), will be fabricated and hooked-up to desired location within the rack assembly, detailed design and pinned type connection will be developed accordingly to suit piping engineer's requirement.
f) Tension cable rod with turnbuckle to serve as plan cross-bracing (see FIG. 15) to resist torsional forces applied at the top flange of main beam due to pipe anchor and friction forces, will be installed to desired location as mandated by piping team within the rack assembly, detailed design and pinned type connection will be developed accordingly to suit piping requirement.

Claims

1. A structural framework assembly of a cabled pipe rack comprising:

a) a fully rigid support at the base by employing starter bars connecting the concrete pedestal and the composite column;

b) a steel base plate with a hole opening same size as the hollow column to allow starter bars and concrete pouring to pass through;

c) a hollow steel section column e.g. circular, square, and rectangular filled-in with concrete to produce the composite column after alignment and anchoring are checked;

d) a cut-off I-beam with a minimum of 600 mm to maximum of 1000 mm in length to be fully welded to the column ring stiffeners to produce a genuine full end moment connection of main transverse beam at column joint;

e) ring stiffeners of column is connected by full welding to hollow steel column and serving as a connector to the cut-off I-beam;

f) anchor structures to serve as anchoring points of horizontal tension cables strategically located at both ends of every pipe rack length, where the anchor structures comprise hollow steel column filled with concrete and are braced to resist anchoring loads;

g) horizontal tension cable with shackle at one end and turn-buckle at the other end, the horizontal cables connecting all the lateral frames to each other and the anchoring structures, so as to serve as lateral support to all transverse frames all the way to the anchoring structures, where the transverse frames comprise two hollow steel columns filled with concrete, cut-off I-beams and main transverse beams;

h) a longitudinal intermediate I-beam to support pipes coming in and out of the pipe rack that is capable to be installed anywhere within the column height by simply using a clamp assembly bolted to the two adjoining columns; and

i) a receiving blinded flange located at the top end of hollow steel column designed to receive upward extension of cabled pipe rack employing a simple bolted flange to flange connection of hollow steel columns.

2. The method of erecting the structural framework of a cabled pipe rack in claim 1, comprising:

a) anchor structures must first be established by erecting at designated locations and have the hallow steel columns be poured with concrete ahead than the transverse frames to give sufficient time of concrete curing;

b) transverse frames will be erected either as a whole or by segments and shall be supported by temporary guying with 4 or 8 nos. tied up to the circular anchors embedded to the side portions of concrete pedestal to hold the frames at vertical position;

c) permanent horizontal tension cables shall only be installed if concrete poured at anchor structures are already cured ready to withstand anchor forces; permanent horizontal tension cables shall only be installed from one end of anchor structures to the first transverse frame all the way to the last frame and finally to the other end of anchor structure only after all transverse frames are completely erected and perfectly aligned. and

d) upward extension of cabled pipe rack is executed by removing the blind cover of the receiving flange at the top end of hollow steel column and install the new hollow steel column extension with a simple bolted flange to flange connection only.

3. The method of producing concrete pedestal of a cabled pipe rack in claim 1, comprising:

a) starter bars for hallow steel columns shall be interconnected to the main steel bars of the pedestal;

b) a minimum of 4 anchor bolts to be used during the erection phase of transverse frames shall be embedded and interconnected to the main bars of pedestal;

c) circular anchors to cater diagonal guying shall be embedded diagonally to both sides of pedestal along the longitudinal axis of pipe rack at a distance of 150 mm below the top of pedestal; and

d) concrete shall be poured only to pedestal if items 3a to 3c are completely installed.

4. The method of producing a robust structural framework of a cabled pipe rack according to claim 1, comprising:

a) concrete shall be poured to the hallow steel columns of transverse frames once permanent horizontal tension cables are completely installed to hold all transverse frames from one end of anchor structure to the other end; and

b) concrete poured to the hallow steel columns of transverse frames shall be cured prior to any placement of pipes and equipment loads to the pipe rack.

5. The method of producing a robust structural framework of a cabled pipe rack according to claim 2, comprising:

c) concrete shall be poured to the hallow steel columns of transverse frames once permanent horizontal tension cables are completely installed to hold all transverse frames from one end of anchor structure to the other end; and

d) concrete poured to the hallow steel columns of transverse frames shall be cured prior to any placement of pipes and equipment loads to the pipe rack.