SE1650697A1 - Construction element, bridge and method for fabricating a construction element - Google Patents

Abstract

The present invention relates to a construction element (100) for a bridge (600) comprising: a core structure (101) formed of porous concrete as a major component, and a load bearing shell (102) of composite material. The composite material comprising a matrix material and a reinforcing fiber material. The present invention also relates to a bridge (600) comprising a construction element (100) and a method (700) for fabricating a construction element (100).Elected for publication: Fig. 1

Description

CONSTRUCTION ELEMENT, BRIDGE AND METHOD FOR FABRICATINGA CONSTRUCTION ELEMENT Technical Field The present invention relates to a construction element for a bridge,and in particular to a construction element comprising composite materialcomprising a matrix material which is reinforced by fibers. The presentinvention also relates to a bridge comprising a construction element and a method for fabricating the construction element.

Background ArtModern infrastructure, such as roads and railroads comprises numerous bridges, used to let the road or railroad in question cross e.g.watervvays or roads. Today, bridges over waterways, roads or similar arecommonly made of reinforced concrete or steel.

Concrete bridges commonly have to be manufactured on site due tothe massive weight of the bridge being manufactured. Further, a lot oftime isspent on manufacturing a form which is then used for molding the concrete.Also a lot of time is spent on positioning reinforcing irons in the form. Theform is commonly made of wooden planks or plywood sheets which are cutand subsequently put together to constitute the form. During molding, theform has to be supported by shorings or posts in order to withstand thepressure and weight exerted by the concrete being molded. This process istime consuming and brings about that e.g. a road or a road section has to beclosed for long periods of time, oftentimes even months. ln case of steel bridges, some off site preproduction is possible, but thebridge commonly at least has to be assembled on site.

Both concrete and steel bridges require a substantial amount ofmaintenance over time in order to withstand varying climate and weatherconditions and substantial loads from traffic passing the bridges.

Concrete bridges suffer from rusting reinforcement irons which reducesthe load bearing capacity of the bridges. Hence, regular repair andmaintenance work is needed. lron bridges tend to rust and resulting in that they need to be painted,repainted and repaired on a regular basis.

Hence, common bridges suffer from large maintenance costs and largecosts for society as roads and similar commonly has to be closed or at leastpartly closed. Typically a bride is maintained for more than 90 years as thelifetime for a bride is typically 100 years or more. The long life time bringsabout large accumulated maintenance costs. When salt is used as anti-skidtreatment on roads, the salt will speed up any corrosion affecting e.g.reinforcing irons or steel bridges, resulting in even more costly and timeconsuming maintenance work.

Not only bridges, but any large construction element of e.g. concrete orsteel which is not easily replaceable and being subjected to weather willsuffer from undesired maintenance cost as described above. Examples ofsuch large construction elements are sections of buildings, façades, beamsand pillars. ln order to reduce maintenance costs and installation time it has beensuggested to use bridges made of materials which are less sensitive tocorrosion and which are lightweight.

US 6,557,201 B1 suggests using a modular composite bride oflightweight material. The suggested bridge addresses some of the aboveproblems but do on the other hand suffer from an undesired instability andundesired acoustic properties.

Hence there is a need for an improved construction element, animproved bridge and a method for fabricating the construction element.

SummaryAccording to an aspect of the invention, the above is at least partly alleviated by a construction element for a bridge comprising: a core structureformed of porous concrete as a major component, and a load bearing shell of composite material comprising a matrix material and a reinforcing fibermaterial.

The present invention is based on the reaiization that prior artcomposite material construction elements used for bridges and other largeconstructions, such as buildings, façades, parking garages or similar suffersfrom undesired wind sensitivity due to their light weight and generally largearea exposed to the wind. Moreover, prior art composite material constructionelements generally produce a significant undesired noise when for instancedriven on by a vehicle. This is due to the fact that a generally hollowconstruction element of a rigid material may act as a sounding box. Moreover,composite material construction elements of the prior art tend to vibrate in anundesired manner when exposed to loads such as vehicles driving on theconstruction element.

Hence, by providing a core structure formed of porous concrete as amajor component, it is possible to provide a construction element which is less sensitive to wind, less prone to undesired noise and undesired vibrations.

At the same time, the construction element is not sensitive to corrosion, as itmay not include any materials which may corrode. This means that theconstruction element will have a reduced need for maintenance throughout itslifetime. lt should be noted that within the context of this application the term“load bearing shell” may be any shell designed to carry the load of theconstruction element including the core structure and any load that theconstruction element is subjected to during normal use. lt should be noted that within the context of this application the term“porous concrete” may be any concrete or cement material comprisingencapsulated gas bubbles or similar. The porous concrete may be forinstance be referred to as gas concrete, lightconcrete, pumice concretelightweight concrete, aerated concrete or air-entrained concrete. Examples ofsuch materials are materials sold under the trade names of SiporexW' andYtongTM. lt should be noted that within the context of this application the term“composite material” may be any material where a plurality of materials areused in combination to form the composite material. According to the presentinvention, a matrix material may be used in combination with a reinforcingfiber material.

The load bearing shell may be wrapped around the core structure,which is advantageous in that the core structure may be used for shaping theload bearing shell. The load bearing shell may hence be completely filled bythe core structure enhancing both mechanical properties and soundproperties.

The load bearing shell may follow a contour of the core structure,which is advantageous in that the core structure may be used for shaping theload bearing shell. 75% by volume or more of the core structure may be made of porousconcrete, which is advantageous in that the density of the core structure maybe adjusted. Moreover, porous concrete is widely available.

The porous concrete may have a density of 1000 kg/ms, or below,which is advantageous in that the density of the core structure may beadjusted to a desired level while keeping the total weight at a desired level The matrix material and the reinforcing fiber material may be providedin form of a sandwich structure, which is advantageous in that a strong lightweight structure may be achieved in well known manner. lt should be notedthat within the context of this application the term “sandwich structure” may beany structure comprising at least two material layers arranged on top of eachother.

The sandwich structure may have different number of layers along alongitudinal direction of the construction element. By this arrangement, thestrength of the construction element may be altered along the longitudinaldirection thereof. For instance, when the construction element is used to spanbetween to bearing points, a larger strength is generally needed in a centrallocation of the construction element as compared to close to the bearingpoints.

The matrix material may be a thermoplastic material, a thermosettingplastic material, a cross-linked plastic material or a combination thereof,which is advantageous in that a strong composite material may be realizedaccording to well established techniques.

The reinforcing fiber material may be selected from a group consistingof, carbon fiber, glass fiber, polymeric fiber, natural fiber, mineral fiber andmetal fiber, which is advantageous in that a strong composite material may berealized according to well established techniques.

The reinforcing fiber material may be in the form of a woven web or aunidirectional web, which is advantageous in that the reinforcing fiber materialmay be provided in a conventional manner, where the web is cut to a desiredsize and shape. lt should be noted that within the context of this applicationthe term “unidirectional web” may be any web where the fibers are not woven,but provided side by side in a common direction. The unidirectional web mayhowever, comprise a plurality of layers of fibers provided side by side in acommon direction, where the fibers of the respective layers may be providedat different angles, e.g. 0 degrees and 30 degrees. This means that the fibersof the respective layers of the unidirectional web may be provided in anydirection with respect to each other, in contrast to a woven web where thefibers generally are arranged at a 90 degree angle. The fibers of theunidirectional web are preferably sewn or stitched together so as to form aweb.

A cross section of the construction element may vary along thelongitudinal direction of the construction element, which is advantageous inthat the strength of the construction element may be altered along thelongitudinal direction thereof.

The core structure may be a self-supporting core structure, which isadvantageous in that the core structure may be handled and stored withoutlosing its shape. Moreover, the core structure may advantageously be usedfor shaping the load bearing shell.

The core structure may comprise a pipe, a tube, or a culvert, which isadvantageous in that electrical wires, pipings or similar may be placed in or through the core structure in a simple manner. Moreover, the use of a pipe, atube, or a culvert provides for that electrical wires, pipings or similar may belaid or exchanged after the fabrication of the core structure.

A length of the construction element in the longitudinal direction of theconstruction element may be between 4m and 100m.

According to another aspect of the invention, there is provided a bridgecomprising at least one construction element of the above type. ln general,features of this aspect of the invention provide similar advantages asdiscussed above in relation to the previous aspect of the invention. Byutilizing at least one construction element of the above type in bridge, abridge which is less sensitive to wind and corrosion may be provided.Moreover, the bridge may be less prone to generate undesired noise andvibrations when traveled upon. Further, the need for maintenance and theinstallation time required may be reduced.

The bridge may further comprise a road surface provided on top of theat least one construction element. By this arrangement, a wearing surfacewhich also enhances the friction may be achieved. Hence, the bridge mayhandle excessive traffic with reduced wear to the construction element.Moreover, a desired friction may be achieved. The road surface maypreferably comprise asphalt or concrete.

According to another aspect of the invention, there is provided amethod for fabricating a construction element. lt should be noted that themethod may incorporate any of the features described above in associationwith the construction element, and has the same corresponding advantages.

A method for fabricating a construction element comprises the steps of: providing a core structure formed of porous concrete as a major component,arranging a reinforcing fiber material and a non-hardened matrix material in asandwich arrangement on the core structure, hardening the matrix material,thereby forming, on the core structure, a load bearing shell comprising acomposite material sandwich structure comprising the hardened matrixmaterial and the reinforcing fiber material.

By the present method a construction element may be fabricated in anefficient way. A core structure formed of porous concrete as a majorcomponent is provided.

The reinforcing fiber material and the non-hardened matrix material areprovided on the core structure in form of a sandwich arrangement. The matrixmaterial and the reinforcing fiber material may be any of the materialsdiscussed above in relation to the previous aspects of the invention.

The non-hardened matrix material is hardened thereby forming, on thecore structure, a load bearing shell comprising a composite material sandwichstructure comprising the hardened matrix material and the reinforcing fibermaterial. lt should be noted that within the context of this application the term“hardening” may be any process where the matrix material concerned ismade harder and more rigid. The hardening may for instance be a cross-linking of a cross-linkable material, a heating of a thermosetting material or alowering of a temperature of a melted material such as a thermoplasticmaterial. Hence, the hardening of the matrix material may be irreversible orreversible.

The step of arranging may comprise wrapping the reinforcing fibermaterial and the non-hardened matrix material in a sandwich arrangement onthe core structure.

The core structure may have a shape resembling a shape of theconstruction element.

The core structure may be provided in form of a plurality of attachablesubstructures. By this arrangement, core structures of various shapes andsizes may be realized in an efficient manner using a limited number ofsubstructures. Moreover, transport and storage of the respectivesubstructures may be simplified as compared to transporting and storing acomplete core structure made of a single piece.

The matrix material may be provided by means of vacuum infusion,which is advantageous in that standard manufacturing processes for composite materials may be utilized when fabricating the constructionelement.

The step of hardening the matrix material may comprise; a firsthardening step, and a second hardening step, wherein the matrix material isheated to a predetermined temperature for a predetermined time during thesecond hardening step, which is advantageous in that load bearing shell ofthe construction element may be given additional mechanical strength. Thematrix material of the load bearing shell may be heated by incorporatinghoses into the matrix material, in which hoses a heated fluid may becirculated. Further the matrix material of the load bearing shell may be heatedby a forced flow of heated air. Furthermore, electrical heating cables may beincorporated in the matrix material or an electrical current may be applied tothe reinforcing fibers of the reinforcing fiber material such that heat isgenerated in the reinforcing fibers.

The step of providing a core structure may be preceded by a step of pouring or casting the core structure, or shaping a block of porousconcrete into the shape of the core structure by grinding, cutting, milling, orcombinations thereof, which is advantageous in that conventional methodsmay be used to manufacture the core structure.

Further features of, and advantages with, the present invention willbecome apparent when studying the appended claims and the followingdescription. The skilled person will realize that different features of thepresent invention may be combined to create embodiments other than thosedescribed in the following, without departing from the scope of the present invenfion.

Brief Description of the Drawinqs Embodiments of the present invention will now be described, by way ofexample, with reference to the accompanying schematic drawings, in which Fig. 1 is a perspective view of a construction element, Fig. 2 is a perspective view of a core structure of the constructionelement of Fig. 1, Figs. 3a-c are perspective views schematically illustrating howreinforcing fiber materials are arranged on the core structure of Fig. 2,Fig. 4 is a perspective view of a bridge comprising two constructionelements, andFig. 5 is a flow chart of a method according to the invention.

Detailed descriptionThe present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments ofthe invention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to the embodiments setforth herein; rather, these embodiments are provided for thoroughness andcompleteness, and fully convey the scope of the invention to the skilledperson.

Now referring to Fig.1, here is conceptually depicted a constructionelement 100. The construction element 100 comprises a load bearing shell102 of composite material. The load bearing shell 102 is formed of acomposite material sandwich structure 105. The composite materialcomprises a matrix material in form of polyester and reinforcing fiber materialsin form of carbon fiber and glass fiber. The load bearing shell 102 is wrappedaround a core structure 101 made of porous concrete. The core structure 101is hence a self-supporting core structure 101.

The load bearing shell 102 is filled by the core structure 101 andfollows the contour of the core structure 101. By this arrangement, the uppersurface of the construction element 100 is backed by the core structure 101,resulting in that the upper surface of the construction element 100 becomesmore rigid which result in that the construction element 100 becomes lessprone to generate noise and vibrations. Further, the core structure 101improves the strength of the construction element 100 due to the fact that theporous concrete used in the core structure 101 can handle compressiveloads. However, the strength of the construction element 100 is mainlydetermined by the strength of the load bearing shell 102.

When designing a construction element 100 of the above kind, theproperties of the load bearing shell 102 may be tailored to suit the needs of aparticular application. For instance, the strength of the load bearing shell 102may be tailored by adapting the amount and type of reinforcing fibers used.Also the directions in which the reinforcing fibers used extend may beadapted in order to adjust the strength of the load bearing shell 102. Further,the number of layers used in the composite material sandwich structure 105may be adapted. Moreover, the number of layers used in the compositematerial sandwich structure 105 may vary along a longitudinal direction L ofthe load bearing shell102 and construction element 100. Yet another way ofadapting the strength of the load bearing shell 102 may be to vary the crosssection of the load bearing shell 102 and hence the construction element 100along its longitudinal length L. Also the overall outer shape of the load bearingshell 102 and hence the construction element 100 may be varied to suitspecific needs. For instance, the requirements relating to shape and strengthmay be very different when the construction element 100 is used in a bridgeas compared to when being used as a façade portion of a building. Moreoverthe size of the construction element 100 may vary greatly depending on thecurrent application. lt is to be noted that the construction element 100 of Fig. 1 is not drawnto scale, but is rather drawn in a simplified manner for illustrative purposes.

Other matrix materials may be used in the construction element 100.The matrix material may be a thermoplastic material, a thermosetting plasticmaterial, a cross-linked plastic material or a combination thereof. Examples ofother suitable matrix materials are vinyl ester, epoxy plastics, acrylic plasticsand phenol plastics.

Other reinforcing fiber materials may be used in the constructionelement 100, such as polymeric fiber, natural fiber, mineral fiber and metalfiber. Further, examples of suitable fibers are cellulose, linen, hemp, jute andbasalt. The reinforcing fiber material may be provided in form of a woven webor a unidirectional web. 11 An outer surface of the construction element 100 may be provided witha layer of gel-coat or paint. By this arrangement the construction element maybe protected from weather conditions, such as UV-radiation and rain.

Trough openings (not shown) in form of a pipe, a tube, a cu|vert orsimilar may be provided through the core structure 101. By this arrangement,wires, pipes, cables or similar may be laid through the construction element100 making use of the through openings.

The fabrication and the composition of the construction element 100 ofFig. 1 will now be described in more detail. ln order to fabricate theconstruction element 100 the core structure 101 is provided first. The corestructure 101 used for the construction element 100 is schematically depictedin Fig. 2. ln the depicted embodiment of Figs. 1 and 2, the core structure 101is formed of porous concrete. The core structure 101 is formed by pouringporous concrete into a mould (not shown). The porous concrete is then left tocure such that the core structure 101 is formed.

Alternatively, the core structure 101 may be formed by shaping a blockof previously cured porous concrete. The shaping of the block may then forinstance be performed using conventional shaping techniques, such asgrinding, cutting, milling, or combinations thereof.

The core structure 101 may alternatively be provided in form of aplurality of attachable substructures (not shown) forming the core structure101.

When the core structure 101 is provided, next reinforcing fibers arearranged on the core structure 101. Now referring to Figs. 3a-c, here isconceptually depicted how reinforcing fibers are arranged on the corestructure 101.

Reinforcing fibers in form of pre-impregnated carbon fibers areprovided in form of unidirectional webs or planks 304. The carbon fibers areprovided as a plurality of layers of unidirectional fibers having a common fiberdirection, as shown in Fig. 3a. The layers are sewn together, before beingimpregnated with a matrix material in form of polyester. Since the fibers of theunidirectional web 304 are pre-impregnated with polyester, the unidirectional 12 web 304 will be rigid or semi-rigid and not as flexible as un-impregnated websof fibers.

The unidirectional webs or planks 304 are arranged on an underside ofthe core structure 101 as two separate webs 304 which are arranged alongtwo parallel longitudinal lines as shown in Fig. 3b.

Following this, reinforcing fibers in form of a unidirectional web 302 ofglass fiber is arranged on the core structure 101 and the webs 304 as shownin Fig. 3c. The unidirectional web 302 of glass fiber is hence wrapped in asandwich arrangement on the core structure 101.

The unidirectional web 302 of glass fiber comprises two layers of glassfibers. The fibers in each layer are arranged in a common direction while thetwo layers are arranged in a 90 degree angle with respect to each other. lnthe depicted embodiment the unidirectional web 302 of glass fibers isarranged such that the fibers of the respective layers are extending in a i 45degree angle with respect to the Iongitudinal direction L of the constructionelement 100 and core structure 101. lt is to be noted that any suitable technique may be used to arrange thereinforcing fibers on the core structure 101. The fibers may for instance bearranged manually on the core structure 101 or may be arrangedautomatically on the core structure 101, using a robot or similar.

After having arranged the unidirectional web 302 of fiber glass and theunidirectional webs 304 of carbon fibers on the core structure 101, thecomplete core structure 101 including the unidirectional web 302 of fiber glassand the unidirectional webs 304 of carbon fiber are inserted into a plasticvacuum bag or similar. Vacuum is applied to the vacuum bag while a plasticmatrix material in form of polyester is infused under pressure through an inletport or through several inlet ports as is known in the art. The polyester thusmigrates through the plastic vacuum bag, infusing the un-impregnated fibersof the unidirectional web 302 and enclosing the pre-impregnated fibers of theunidirectional webs 304. After completion of the vacuum infusion, the infusedpolyester material will have been hardened by being polymerized as is known 13 in the art, hence forming a load bearing shell 102 of composite materialcomprising a matrix material and a reinforcing fiber material.

Following the initial hardening of the infused polyester material thecomplete core structure 101 including the unidirectional web 302 of fiberglass, the unidirectional webs 304 of carbon fiber and the polyester matrixmaterial may be heated to a predetermined temperature for a predeterminedtime in order to further harden the polyester matrix material. The duration andtemperature of the hardening will be determined by the particular matrixmaterial used. As an example, the hardening may take place at a temperatureof about 120°C. ln order to heat the core structure 101 including the unidirectional web302 of fiber glass and the unidirectional webs 304 of carbon fiber 104 to anelevated temperature, several techniques may be used. For instance, hosesor heating cables may be incorporated in the matrix material or an electricalcurrent may be applied to the carbon fibers of the unidirectional web 304.Other suitable techniques known in the art may also be used.

The core structure 101 including the unidirectional web 302 of fiberglass and the unidirectional webs 304 of carbon fiber 104 may be removedfrom the vacuum plastic bag prior to or after the hardening at the elevatedtemperature. lt is to be noted that the core structure 101 may comprise othermaterials than porous concrete. Preferably 75% by volume or more of thecore structure is made of porous concrete. Preferably, the porous concretemay have a bulk density which is lower than 1000 kg/m3. ln addition to porous concrete, the core structure 101 may comprisecellular plastic, expanded plastic, air filled bellows, LECATN' or similar as afilling material. Preferably, the filling material may have a bulk density which islower than 250 kg/m3, more preferred a bulk density which is lower than 100kg/m3.

Now referring to Fig. 4, here is conceptually depicted a bridge 600spanning over a watervvay 602. The depicted bridge 600 is a road bridgeused for letting a road 604 pass over the waten/vay 602. The bridge includes 14 two construction elements 100 of the type depicted in Fig. 1. Each of theconstruction elements 100 spans the entire length of the bridge 600. Theconstruction elements 100 are arranged side by side such that eachconstruction element 100 carries one lane of the road 604. The constructionelements 100 are provided with a road surface 606 on their respective topsurfaces. The road surface reduces wear to the construction element 100 andincreases the friction. The road surface is preferably made of asphalt orconcrete.

The respective construction elements 100 may be fabricated inproximity to the location of the bridge 600, such that respective constructionelements 100 may be lifted into their final positions using a mobile crane orsimilar.

The respective construction elements 100 may be fabricated in alocation distant from the location of the bride 600 and subsequently moved tothe location of the bridge 600 using a truck or similar.

The respective construction elements 100 may be handled andtransported although typically having a length in the longitudinal direction L of4 to 100 m. This is possible due to the fact that the respective constructionelements 100 may be fabricated using a relatively speaking light material.

A 50 m construction elements 100 with a width of 6 m typically weighsabout 25 tones. lt is to be noted that a plurality of construction elements 100may be arranged after each other thereby forming a bridge 600 being longerthan the respective construction elements 100 used. When using thisarrangement, each construction element 100 spans between two bearingpoints, such as foundations, pillars or similar. Hence, it is possible to build abridge 600 of any length, by arranging a plurality of construction elements 100after each other. Similarly, a bridge 600 of any width may be built byarranging a plurality of construction elements 100 side by side.

Moreover, a construction element 100 according to the invention maybe used as a pillar for a bridge.

Furthermore, in addition to being used for bridges 600 or similar, theconstruction element 100 may be used in other relatively speaking large constructions. For example, the construction element 100 may be used inbuildings, façades, beams, parking garages or similar. ln the following a method 700 fabricating a construction element 100will be described with reference to Fig. 5 showing exemplifying steps forfabricating a construction element 100.

Now referring to Fig. 5, showing exemplifying steps of a method 700for fabricating a construction element 100. ln a first step 702, a core structure 101 formed of porous concrete as amajor component, is provided. ln a second step 704, a reinforcing fiber material and a non-hardenedmatrix material are arranged in a sandwich arrangement on the core structure101. The reinforcing fiber material and the non-hardened matrix material maybe arranged on the core structure 101 using any suitable techniques,including the techniques described above when describing how theconstruction element 100 of Fig. 1 may be fabricated. ln a third step 706, the matrix material is hardened, thereby forming acomposite material sandwich structure 105 comprising the hardened matrixmaterial and the reinforcing fiber material. The matrix material may behardened using any suitable techniques, including the techniques describedabove when describing how the construction element 100 of Fig. 1 may befabricated.

Although the figures may show a specific order of method steps, theorder of the steps may differ from what is depicted. Also two or more stepsmay be performed concurrently or with partial concurrence. Such variation willdepend on the systems chosen and on designer choice. All such variationsare within the scope of the disclosure. Additionally, even though the inventionhas been described with reference to specific exemplifying embodimentsthereof, many different alterations, modifications and the like will becomeapparent for those skilled in the art. Variations to the disclosed embodimentsmay be understood and effected by the skilled addressee in practicing theclaimed invention, from a study of the drawings, the disclosure, and theappended claims. Furthermore, in the claims, the word "comprising" does not 16 exclude other elements or steps, and the indefinite article "a" or "an" does notexclude a plurality.

Claims (23)

1. Construction element (100) for a bridge (600) comprising:a core structure (101) formed of porous concrete as a majorcomponent, anda load bearing shell (102) of composite material comprising a matrixmaterial and a reinforcing fiber material.

2. Construction element (100) according to claim 1, wherein the loadbearing shell (102) is wrapped around the core structure (101 ).

3. Construction element (100) according to claim 1 or 2, wherein theload bearing shell (102) follows a contour of the core structure (101).

4. Construction element (100) according to anyone of the previousclaims, wherein 75% by volume or more of the core structure (101) is made ofporous concrete.

5. Construction element (100) according to anyone of the previousclaims, wherein the porous concrete has a density of 1000 kg/ms, or below.

6. Construction element (100) according to any one of the precedingclaims, wherein the matrix material and the reinforcing fiber material are provided in form of a sandwich structure (105).

7. Construction element (100) according to claim 6, wherein thesandwich structure (105) having different number of layers along alongitudinal direction (L) of the construction element (100).

8. Construction element (100) according to any one of the precedingclaims, wherein the matrix material is a thermoplastic material, a 18 thermosetting plastic material, a cross-linked plastic material or a combinationthereof.

9. Construction element (100) according to any one of the precedingclaims, wherein the reinforcing fiber material is selected from a groupconsisting of, carbon fiber, glass fiber, polymeric fiber, natural fiber, mineralfiber and metal fiber.

10. Construction element (100) according to any one of the precedingclaims, wherein the reinforcing fiber material is in the form of a woven web ora unidirectional web.

11. Construction element (100) according to any one of the precedingclaims, wherein a cross section of the construction element (100) varies alongthe longitudinal direction (L) of the construction element (100).

12. Construction element (100) according to anyone of the previousclaims, wherein the core structure (101) is a self-supporting core structure(101 ).

13. Construction element (100) according to anyone of the previousclaims, wherein the core structure (101) comprises a pipe, a tube, or aculvert.

14. Construction element (100) according to any one of the precedingclaims, wherein a length of the construction element in the longitudinaldirection (L) of the construction element (100) is between 4m and 100m.

15. Bridge (600) comprising at least one construction element (100)according to any one of the previous claims. 19

16. Bridge (600) according to claim 15, further comprising a roadsurface (606) provided on top of the at least one construction element (100).

17. Method (700) for fabricating a construction element (100)comprising the steps of: providing (702) a core structure (101) formed of porous concrete as amajor component, arranging (704) a reinforcing fiber material and a non-hardened matrixmaterial in a sandwich arrangement on the core structure, hardening (706) the matrix material, thereby forming, on the corestructure (101), a load bearing shell (102) comprising a composite materialsandwich structure (105) comprising the hardened matrix material and thereinforcing fiber material.

18. Method (700) according to claim 17, wherein the step ofarranging (704) comprises wrapping the reinforcing fiber material and thenon-hardened matrix material in a sandwich arrangement on the corestructure (101 ).

19. Method (700) according to claim 17 or 18, wherein the corestructure (101) having a shape resembling a shape of the constructionelement (100).

20. Method (700) according to anyone of claims 17 to 19, wherein thecore structure (101) is provided in form of a plurality of attachablesubstructures.

21. Method (700) according to any one of claims 17 to 20, wherein thematrix material is provided by means of vacuum infusion.

22. Method (700) according to any one of claims 17 to 21, wherein thestep of hardening (706) the matrix material comprises; a first hardening step, and a second hardening step, wherein the matrix material is heated to apredetermined temperature for a predetermined time during the secondhardening step.

23. Method (700) according to anyone of claims 17 to 22, wherein thestep of providing (702) a core structure (101 ), is preceded by a step of pouring or casting the core structure (101 ), or shaping a block of porous concrete into the shape of the core structure(101) by grinding, cutting, miiiing, or combinations thereof.