Construction process of structures with empty segments and construction system of structures with empty segments
10513858 · 2019-12-24
Assignee
Inventors
- Pedro Alvares Ribeiro DO CARMO PACHECO (Matosinhos, PT)
- David Fernandes MARTINS RAMOS (Rio Tinto, PT)
- Diogo Teixeira GRACA MOURA (Nevogilde, PT)
- Hugo Edgar Norberto SOARES COELHO (Lugar de Capelos, PT)
- Pedro Henrique BAPTISTA BORGES (Pedroso, PT)
Cpc classification
E04C5/08
FIXED CONSTRUCTIONS
E01D19/00
FIXED CONSTRUCTIONS
E01D21/00
FIXED CONSTRUCTIONS
E01D19/02
FIXED CONSTRUCTIONS
E04G13/04
FIXED CONSTRUCTIONS
International classification
E01D21/00
FIXED CONSTRUCTIONS
E01D19/00
FIXED CONSTRUCTIONS
E04G13/04
FIXED CONSTRUCTIONS
E04G13/00
FIXED CONSTRUCTIONS
E04C5/08
FIXED CONSTRUCTIONS
E01D19/02
FIXED CONSTRUCTIONS
Abstract
An industrialized construction process is provided in which the filling material (8) is poured in situ on empty segments (3) prefabricated ex situ. The process comprises the prefabrication of empty segments (3) including the assembling of steel reinforcement elements (9) and assembling fixing elements (4) whereby these comprise rigid elements (22) and at least part of the moulds (13), which occur at a location (5) ex situ; transport and placement of the empty segments (3) in the final position in the structure (1); pouring the filling material (8); consolidation or curing of the filling material; prestressing the structure (1); and removal of the moulds (13) and fixing elements (4). The present invention also relates to a construction system adapted for carrying out the construction process.
Claims
1. A process for constructing at least part of a structure (1) configured to be divisible into one or more reference segments (2), comprising: prefabricating empty segments (3), ex situ, configured with a geometry corresponding to a geometry of respective reference segments (2) and configured to receive a filling material (8), wherein the prefabricating of said empty segments (3) includes assembling steel reinforcements (9), fixing elements (4), first molds, and a system of rigid elements (22), wherein said fixing elements (4) are configured to stabilize said empty segments (3) during a transport phase from the ex situ location to an in situ location and to maintain stability of said empty segments (3) after placement at the in situ location, wherein said rigid elements (22) are configured to support said steel reinforcements (9) and said first molds (13) included with said fixing elements (4); transporting of said empty segments (3) from the ex situ location to the in situ location; placing said empty segments (3) in a final placement position corresponding to the respective reference segments (2) of said structure (1); providing second molds to said empty segments after placing said empty segments in the final placement position; filling said empty segments (3), after placement in the in situ location, with filling material (8) without discontinuity of said filling material (8) in existing interface areas between any two adjacent reference segments (2) of said structure (1); consolidating the filling material (8) in order to obtain at least part of the structure (1) to be constructed, and removing said fixing elements (4), the first molds, and the second molds.
2. The process according to claim 1, wherein the prefabricating the empty segments (3) includes the assembling of prestressing ducts (10).
3. The process according to claim 1, further comprising: in situ introduction of prestressing cables (11) after the in situ assembling of at least one of said empty segments (3), and carrying out a tensioning of said cables (11) in situ, after the filling of the filling material (8) and the consolidating of the filling material.
4. The process according to claim 1, further comprising: designing the structure (1), which includes a verification of limit states and use in existing interface sections between any two adjacent reference segments (2) and not trespassed by the steel reinforcement elements (9).
5. The process according to claim 1, wherein the prefabricating of the empty segments (3) includes introducing prestressing cables (11) ex situ and carrying out a tensioning of the prestressing cables (11) in situ, after the filling with the filling material (8) and the consolidating of the filling material.
6. The process according to claim 1, wherein the prefabricating of the empty segments (3) includes assembling of at least one of the following: interface elements, inserts (12), including profiles of metallic material, carbon fiber (31), prefabricated anchoring blocks (29), other prefabricated elements (33), positioning elements of the steel reinforcements, or isolation devices (25) for execution of negatives in the filling material (8).
7. The process according to claim 1, wherein the prefabricating of the empty segments (3) includes assembling of seals (30) adapted to be arranged as interface elements between the first molds (13), or the second molds, or other interface elements to be arranged between said empty segments (3).
8. The process according to claim 1, further comprising assembling additional steel reinforcements (21) in said empty segments (3) in the in situ location.
9. The process according to claim 1, wherein the prefabricating of said empty segments (3) includes: providing prestressing cables (11) to said empty segments in the ex situ location, and tensioning of the prestressing cables (11) in the ex situ location, and after the transporting of the empty segments to the in-situ location, pre-tensioning transmission of said fixing elements (4) to the filling material (8).
10. The process according to claim 1, further comprising: in situ removal of the fixing elements (4) and part or all of said first molds and said second molds; transporting said fixing elements (4) back to a prefabrication area of the ex situ location (5); starting a next cycle of prefabricating.
11. The process according to claim 1, further comprising ex situ assembling of a plurality of sets of the fixing elements (4), in order to allow more than one front of prefabrication of empty segments (3).
12. The process according to claim 1, wherein the prefabricating of said empty segments (3) is executed separately from and at least partly simultaneously with the construction of at least part of the structure (1) using structure segments corresponding to reference segments (2) or special pier segments (28).
Description
DESCRIPTION OF THE FIGURES
(1) The invention will now be explained in greater detail based on preferred embodiments and the Figures that are attached.
(2) The Figures show, in simplified schematic representations:
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DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
(32) The present invention relates to a new construction process and a construction system of structural elements, for example, reinforced concrete, with several configurations, as shown in
(33) In order to understand better, the reference segments (2) may coincide in terms of form and constitution with the conventional prefabricated concrete elements and may be segments that cover the span (corresponding to prefabricated beams) or segments with integral cross-section (corresponding to prefabricated segments), or to integral segments (corresponding to complete prefabricated segments), or segments of prefabricated piers, segments of other prefabricated elements, such as curved elements, sloped elements, concrete cores, etc.
(34) Analyzing
(35) Analyzing
(36) In the case of, for example, reinforced concrete structures, the empty segment (3) comprises passive steel reinforcements (9) already with the final geometric configuration.
(37) In the case of structures (1) of, for example, prestressed reinforced concrete, the empty segments (3) include prestressing ducts (10) and the prestressing cables (11) can be introduced after the assembling of one set of empty segments (3) that are concreted in one same operation, for example, corresponding to a span in the case of a bridge deck. The cables can be fully placed if their length is equal to or less than the empty segment (3).
(38) If the structure (1) is composite or has interface elements or inserts incorporated (12) (for example, metallic elements) that become incorporated in the filling material (8), these elements can also be incorporated in the empty segments (3).
(39) By means of the operation of pouring the filling material (8), and after consolidation of the filling material, the empty segment (3) becomes, therefore, the reference segment (2). In the case of structures (1) of reinforced concrete, this pouring operation is the concreting operation.
(40) With reference to
(41) If the fixing element (4) is dimensioned to have structural capacity to support the filling material (8), then the empty segment (3) can be placed without the use of shoring systems (6), as shown schematically in
(42) With reference to
(43) An important aspect in the application of the construction process in accordance with the present invention is the fixing element design (4). This element must comply with three requirements: i) ensure the final geometry, or close to the final one, of the elements that make up the empty segment (3) so that, by means of quick and simple operations, it is easy to ensure the desired geometry for the empty segment (3) after it is placed; ii) have the structural capacity to ensure the empty segment stability (3) in its transport and placement; and (iii) be compatible with the moulds (13) of the element to be constructed that are not included in the fixing element (4), or including those same moulds (13).
(44) Additionally, it may also be advantageous, for the fixing element (4) to be previously prepared so as to be easily positioned, for example including fixing devices (16) that can be both positioners and fixing devices (16), or other devices which ensure the correct positioning of the empty segment (3).
(45) In
(46) The fixing elements (4) may, for example, include all the moulds from the outset (13), for example the formwork, as in the cases of
(47) The fixing elements (4) include rigid elements (22) and may include, for example, adjusting devices (15) which may be useful not only to adjust the final geometry of the empty segment (3) but may also be useful to facilitate the removal of the fixing elements (4) after the empty segment (3) is filled by the material (8) and this is properly consolidated, or even to move or lift part or all of the fixing elements (4).
(48) The adjusting elements (15) may consist of mechanical elements for manual adjustment, for example mechanical spindles, or other mechanical elements known in the state of the art, such as hydraulic jacks, manual spindles, retractable elements, or others with similar functions.
(49) In
Example of Application of the Invention
(50) Next, and only by way of example, follows an explanation of the application of the construction process in accordance with the present invention to the construction of prestressed box girder decks concreted in situ using, for example, a shoring system (6) which is self-launching scaffolding. The necessary adjustments for the application of this process to other types of structures are explained later on.
(51) This construction process, when applied to this example, comprises seven stages: A. Prefabrication of empty segments (3), including assembling of fixing elements (4) in an ex situ prefabrication area (5); B. Transport and placement of the empty segments (3) in the scaffolding (6); C. Concreting of the structural element (1); D. Curing period; E. Prestressing of the structure (if any) and removal of scaffolding; F. Removal of the fixing elements (4) and transport to prefabrication area (5).
(52) With reference to
(53) It is possible that, for example, the deck (1), with a box girder cross-section indicated in cutaway A-A, for example, can be executed with several reference segments (2) per span. Each reference segment (2) to be constructed corresponds to an empty segment (3).
(54) With reference to
(55) Phase APrefabrication of Empty Segments (3), Including Assembling of Fixing Elements (4) in an Ex Situ Prefabrication Area (5);
(56) This phase is explained based on
(57) The fixing elements (4) could, in this example, have the configuration defined in
(58) The fixing elements (4) to use in each cycle (except in the first cycle) are from the works front line, where they were used in a previous cycle. A preliminary operation, applicable to this example, consists in cleaning and painting with form release agents, or similar products, the modules, the inner formwork (13) that, in this example, are an integral part of the fixing element (4).
(59) The empty segments (3) are prefabricated by assembling the steel reinforcements (9) in a manner compatible with the assembling of fixing elements (4) that integrate the empty segments (3), and part of the moulds (13) (inner formwork) which in this example is also part of the fixing element (4), and these three activities must be carried out in order to comply with the geometry of the reference segment (2) corresponding to the segment to be executed of the works, i.e. complying with the geometry of the final structure (1).
(60) To increase productivity and quality control, steel reinforcement spacing elements can be used (23) i.e. gabarits for positioning the steel reinforcements, for example, pierced steel sheets with strict position of each rod or cable, pieces of wood, pieces of concrete; in other applications these elements may also be an integral part of the (4) fixing elements, as shown for example, in
(61) There may be an assembly line, for example, as schematically shown in
(62) Depending on the structure (1) designed, the empty segments may include prestressing ducts (10), interface structures or inserts (12), or other elements that are part of the final structure (1) that can be incorporated in the prefabrication, as, for example, the prefabricated anchoring blocks (29), prefabricated elements (33) (see
(63) The empty segments (3) must be made with the same or very similar geometry to that which ensures the correct execution of the final structure (1) and the fixing elements (4) must ensure the stability of the empty segments (3) during transport and placement. The fixing elements must be compatible with the moulds (13), in this case the formwork, which are not included in them, and, as is the case of this example, include the inner formwork (13) as shown in
(64) If each empty segment (3) has a sole position for placement in the shoring (6), it may be appropriate to mark the empty segments (3), for example, by numbering them.
(65) The fixing element segments (4) may also be provided with collective safety equipment, e.g. guards, platform, or safety belts fixing elements, which may be useful for carrying out the work safely.
(66) In the case of the fixing elements (4) incorporating elements that trespass the filling material (8), in this case concrete, as it happens, for example, in the fixing element (4) in
(67) In some cases, the empty segments (3) fabrication process can be more productive and with greater quality control, if the assembling of the empty segments (3) is carried out in the prefabrication area (5) on a platform, with an L1 extension, which can hold simultaneously and continuously all the empty segments (3) pertaining to the same execution phase.
(68) Phase BTransport, Placement and Fixing of the Empty Segments (3) in the Scaffolding (6);
(69) This phase is explained based on
(70) According to
(71) Note that an empty segment (3) has dimensions and weight suitable for easy transport to the shoring system, for example a scaffolding, and for easy lifting and placement in the scaffolding (these elements may weigh several times less than an element of prefabricated concrete, (i.e. than the corresponding structure segment (1)).
(72) As shown in
(73) The design of the fixing elements (4) must take account the empty segments (3) type of supply to be carried out in the works. It may be appropriate, for example, to use more complete fixing elements (4), similar to those in
(74) In the case of using overhead scaffolding (6), the plan view dimensions of the empty segments (3) must be made compatible with the support elements (20) of the scaffolding (6) (shown in
(75) The placement of the empty segments (3) in the final position can be made by auxiliary means similar to the auxiliary means (7) of the prefabrication area, or it may be performed by auxiliary means (19) incorporated in the scaffolding (6).
(76) As can be seen in
(77) The fixing elements (4) may also include interface fixing devices (16) between them and seals (30) or other interface materials to ensure an airtight closing of the moulds (13) (as shown in
(78) Depending on the design criteria, the empty segments (3) may, for example, have no connection between them (see
(79) Empty segments (3) with steel reinforcement (9) which penetrate into the adjacent empty segment (as shown in view B-B of
(80) It is also possible to adopt, for example, a solution, shown in
(81) Alternatively, the overlapping reinforcement elements or overlaps (21) may travel with the empty segments (3) without being fixed, and it is possible to slide them when the empty segments (3) are already in their final position.
(82) There may also be a design of fixing elements (4) and moulds (13) providing for the placement of closing moulds elements (24) in situ, schematically shown in
(83) Depending on the design of the fixing elements (4), after placement of the empty segments (3) part of the moulds can be introduced (13), for example, the inner moulds, which in the case of the fixing elements having a design similar to that shown in
(84) Finally, after all the empty segments have been placed (3) in the shoring system (6) and any additional works have been executed in situ as previously mentioned, in the case of the structure (1) being designed with prestressing, with the respective cables having an extension above the empty segments (3), then ducts (10) connecting elements must also be placed in situ, and the prestressing cables (11) must also be introduced in an in situ operation at the works front line, similarly to what happens in traditional construction with prefabricated segments.
(85) The shoring system (6) may be prepared for the installation of lifting equipment (19) that allows the placement of prestressing coils under the deck. The installation of the prestressing cables is performed after the prestressing ducts sealing (10).
(86) Phase CConcreting of the Structural Element (1);
(87) The operation of pouring the filling material (8), which in this example coincides with the concreting operation of the deck, may have very variable durations, and usually means several hours for the example being described. In this operation, a number of specialized operators will pour and vibrate the liquid concrete in all the empty segments (13) located between two consecutive construction joints (18), i.e. of a portion of the structure (1) to be constructed. Normally, as the extension to be executed in each cycle has, for example, dimension L (indicated in
(88) The shoring system (6) which can be, for example and as already mentioned, self-launching scaffolding, can be equipped with elements that allow the creation of concreting circuits along the stretch to be constructed, for optimization of this process.
(89) Note that the operation in question, in the example shown, is identical to the normal concreting operation of the in situ construction methodology, without any influence of segmentation of the deck in that process, which is continuous and follows the normal rules of the state of the art for in situ concreting.
(90) The same application principles apply if the filling material (8) is not concrete, but should also take into account the particularities of the material involved.
(91) It should be noted that the filling of the empty segments (3), if there is more than one, does not imply the existence of the filling material discontinuities in the interface areas between empty segments (3).
(92) If concrete accelerating admixtures (31) are incorporated in the fixing elements (4) or in the shoring systems (6) the curing periods may be shortened.
(93) Phase DCuring Period;
(94) In the example shown, with structures in prestressed reinforced concrete, the curing period can mean dozens of hours and must be defined case by case, according to the rules of the state of the art for structures concreted in situ, and depending on the particular characteristics of the deck (or other structural member), for example, type of concrete, inclusion of prestressing or not, necessary resistance to the prestressing application and other common state of the art specifications that are applicable.
(95) Depending on the conditions of the location of the works and the technical requirements, additional operations may be needed to ensure a proper curing, for example, watering the elements in consolidation.
(96) In the case of filling material (8) is not concrete, the time of consolidation should be defined accordingly.
(97) Phase EPrestressing of the Structure (if any) and Removal of Scaffolding;
(98) In the case where the structure (1) is, for example, prestressed, including elements of the prestressing type (10) and (11) or others, before the removal of the scaffolding takes place, the cables, or other prestressing elements, must be tensioned according to the tensioning plan provided for, and it can be a partial or total tensioning.
(99) Then follows the removal of scaffolding of the structure (1), which is no more than disengaging the shoring system (6) from the weight of the part of the structure (1) being executed. This operation can be performed, for example, by manual or mechanical means, and can be done, for example, through a sequence of small localized operations, or through a single global operation with mechanical means designed for this purpose and known in the state of the art. This task may benefit from, for example, the use of an automatic control system of scaffolding deformations (6) depending on their structural response.
(100) Normally, this operation is followed by the transposition of the shoring system (6) to the next portion of the structure (1), in this example to the next span of the structure (1) to be constructed. Where the shoring system (6) is self-launching scaffolding, this operation is the forward operation.
(101) Phase FRemoval of the Fixing Elements (4) and Transport to Prefabrication Area (5).
(102) At the same time, before or after the transposition of the shoring system (6) to a new position, a team of operators starts removing the fixing elements (4), which, for example, include the inner moulds (13).
(103) If the fixing elements (4) have elements that trespass the filling material (8) as is the case of the fixing elements in Figurea 14a-14d, the fixing elements (4) must be separated into two or more parts.
(104) Still based on
(105) This removal will also be easier if, as shown in
(106) In the case of the example shown, the construction of a prestressed reinforced concrete deck, carried out with empty segments (3) with fixing elements (4) including inner moulds (13) as, for example, retractable systems illustrated in
(107) External auxiliary equipment (7), for example, or, also for example, auxiliary equipment (19) of the shoring system itself (6), may be used to facilitate the removal of the fixing elements (4) and placement in a means of transport (17) (with characteristics compatible with the type of supply previously defined) that will take them to the prefabrication area (5) where they will be used for the prefabrication of a new series of empty segments (3), thus starting a new cycle.
(108) To increase productivity, it may be convenient to have a plurality of fixing elements sets (4) for each position. In such a way that, while a set of empty segments (3), including the respective fixing elements (4), is being used at the works front line, for the construction of the current stretch, another set (or more than one) of fixing elements (4) is in the prefabrication area (5) so that, at the same time, the next stretch is already being prefabricated, or several of the next stretches, if so defined.
(109) In the case of using this process in overhead self-launching scaffolding, for example, a special pier segment (28) can be previously executed that, in addition to the components of an empty segment (3), can have incorporated, for example, a pre-slab and a frame of the shoring system (6). This special pier segment (28) may alternatively, and also for example, be a conventional prefabricated segment, already with filling material. In this case, this is the segment corresponding to segment 0.
(110) In these special pier segments (28), the fixing element (4) can be different and need not have connections to the scaffolding, as can be seen in
(111) The construction process in accordance with the present invention can be applied in various types of shoring systems (6) (lower self-launching scaffolding, ground scaffolding, or others) simply by making the adaptations resulting from the characteristics of the shoring systems, with impact on the choice of means of transport (17) and in the design of the fixing elements (4), and may also influence the design of auxiliary equipment (19) of shoring systems (6). It is good project practice to develop the project with a simultaneous selection of the type of shoring system (6) to be adopted.
(112) The application of the construction process in accordance with the present invention to reinforced concrete structures without prestressing (10) and (11) is in everything identical to that presented in this text, without the tasks/actions and elements related to the prestressing.
(113) In the construction of concrete structures, several structural systems, with several horizontal shapes can be executed by this method (see
(114) Likewise, the construction process according to the present invention can be used in the construction of structures (1) of reinforced (and/or prestressed) concrete with different cross-sections, as for example the A-A cutaway section of
(115) In some cases, as in the example of
(116) This method without shoring system (6) can also be applied in elements such as shown in
(117) The application of the construction process in accordance with the present invention to structures (1) executed with other materials, for example, glass, ceramic, plastic or with hydraulic binders other than those used in reinforced concrete, is also possible provided the structure (1) to be constructed is divisible into one or more structure segments (2) and can justify and reveal advantages if this structure (1) is composite, either including steel reinforcement materials (9) or interface structures or inserts (12), and may also include or not, active reinforcement elements (11) and active reinforcement ducts (10), if necessary, and in which there are advantages to pouring the filling material (8) in situ in a place other than the place of prefabrication of the empty segments.
(118) For example, this type of solution can be used to construct library or warehouse shelving made of plastic, with steel reinforcements (11) and/or rigid inserts (12), in plastic reservoirs with steel reinforcements (9) and/or active reinforcement (11), or glass structures with a wide span to be executed in situ, and that include steel reinforcements (9) and/or inserts (12), or, more generally, composite structures in which it is advantageous to pour the filling material (8) in situ.
LIST OF REFERENCE INDICES
(119) 1. Structure, to be constructed 2. Reference segment, of structure to be constructed 3. Empty segment 4. Fixing elements 5. Prefabrication area 6. Shoring system (scaffolding) 7. Auxiliary equipment (for cargo handling in the prefabrication area) 8. Filling material 9. Steel reinforcement elements 10. Prestressing ducts 11. Active reinforcement elements (prestressing cables) 12. Interface structure or insert 13. Mould (for example formwork) 14. Handling device and/or positioning of the formwork 15. Mechanically adjustable elements (spindles, jacks, etc.) 16. Interface fixing devices (fixing devices or positioners, or positioner fixing devices) 17. Means of transport 18. Construction joint 19. Scaffolding auxiliary means (means of transport of loads) 20. Support elements of the shoring system 21. Overlapping elements or steel reinforcement overlaps 22. Rigid elements (of the fixing elements) 23. Position elements of steel reinforcement elements 24. Mould closing elements 25. Isolation Devices (trespass of filling material, negatives in the filling material) 26. Sliding devices 27. Gripping devices 28. Special pier segments 29. Prefabricated anchoring blocks 30. Seals or interface elements between segments 31. Concrete accelerating system (for example, by steam) 32. Reaction rigid elements for tensioning 33. Prefabricated elements