WO2014194951A1 - Particularly low-maintenance züblin system post anchoring on engineering structures - Google Patents

Abstract

The post anchoring according to the invention for protective walls on engineering structures provides a spherical washer/conical seat system for compensating possible angled positions with the aim of an approximately central load application, the anchoring elements being preloaded and the preloaded free length thereof being enclosed by a preferably viscoelastic, anti-corrosion medium. The post anchoring comprises an insert element, which is inserted into the concrete of the structure. Alternatively, a subsequent anchoring is accomplished by producing holes in the already produced structure concrete. Said holes can be through-holes, in which case the anchoring is accomplished by means of an anchor rod that extends through the hole and a corresponding counter-threaded connection. The hole can also only be made down to a required anchoring depth, in which case an anchoring rod is glued into the drill hole.

Description

 TITLE

 Particularly low-maintenance post anchoring System Züblin on engineering structures DESCRIPTION

Technical area

 The invention relates to an arrangement for fixing posts for protective walls on structures or foundations.

State of the art

 In the construction of protective walls, for example, noise protection, wind protection, anti-glare, sound insulation walls or the like. Embedded concrete elements or concrete anchored by concreting the structures or foundations threaded rods or glued on buildings or foundations in the rule. The

Protective walls are sometimes subjected to high loads depending on the ambient conditions, whereby not only wind and storm exert considerable forces on the wall elements and the posts on which they are accommodated. By passing trains or motor vehicles, especially the goods traffic high dynamic loads in the form of pressure and suction effect on the wall in the built-in elements and thus in the structures or foundations are initiated. Thus, e.g. Investigations on high-speed railways of the Deutsche Bahn have shown that there is a high-grade dynamic load, which has a great influence on the durability of the structure.

An inclination of the anchoring elements has a significant negative effect on the durability of the connection. Since the incorporation of the installation elements is a manual process and therefore subject to the conditions of the construction site in terms of accuracy, a sufficient reduction of the misalignment of the mounting elements during assembly can not be ensured. In EP 2 159 354 A1, a system of conical socket and spherical disk has been proposed which can compensate deviations from the desired position of the anchoring rods to a certain extent. However, this can still be improved for the extreme dynamic stresses in the region of the high-speed railways in order to ensure even greater durability of the structures. Object of the invention

 The object of the invention is, in the case of extremely high demands of high-speed lines to provide an arrangement for attachment of posts, through which the negative effects of misalignment of built-in elements and the strong AC voltages in the fasteners due to the highly dynamic effects on the Durability excluded or at least reduced. At the same time, the necessary maintenance interval of the post fixtures should be increased to 50 years or more!

Presentation of the invention

 This object is achieved by an arrangement for fastening posts for protective walls with the features of claim 1.

Surprisingly, it has been found by experiments that for certain types of mullion anchor bolts which have been tightened with a certain preload according to a certain procedure, the maintenance interval of this gland can be extended to at least 50 years compared to previous methods of only 10 to 15 years!

The application of the bias is done in such a way that about 24 hours or later after the production of Pageis by grout a tightening torque is applied to the fastening nuts, which is 75% of the necessary according to the blueprint tightening torque. (Only then may the wall elements of the noise barrier be installed.)

 - If the pretension of 75% is applied within one week of grouting, a first retightening (100%) must be made approximately 7 days after tempering.

 - If the pretension of 75% occurs only after 7 days or later after grouting, a first retightening (100%) is required within 1 to 3 weeks after this tempering.

Approximately 6 months after grouting, a final (second) re-tensioning with 100% is to be carried out.

Typical values of prestressing, as required on posts for noise protection walls in addition to high-speed lines, are approximately between 25 and 120 kN, usually between 60 and 90 kN, for 8.8 threaded rods. The tightening torques of the fastening nuts are approximately between 100 and 550 Nm, usually between 250 and 400 Nos. The negative influence of the misalignment of the mounting elements on the durability of the attachment is due to the fact that the skewed threaded bolt an eccentric load introduction arises, which acts as a bending stress on the threaded bolt and thus represents an additional burden. The compensation device, which according to the invention comprises a conical socket and a spherical disk, makes it possible to compensate misalignments of the threaded bolts on the installation elements and thus to initiate the load centrally, ie in the direction of the longitudinal axis of the threaded bolt. As a rule, angle deviations of up to 3 ° can be compensated. In addition, due to the recurrent high dynamic load on the fastening detail, an interaction between loading and unloading, which is often accompanied by a change of sign of the stresses in the anchoring element. By applying a defined preload on the anchoring the deformation of the compound - and thus an additional deviation of the post from the desired position with the associated effects - and the voltage situation can be changed in the element, so that in terms of durability and thus the durability of the anchoring compound a significant Improvement is achieved. In order to ensure the required preload level of the connection, relevant influencing factors over the period of use are taken into account in the design and the preload force is calculated accordingly and fixed at the screw connection. Although a gland is achieved according to the invention, which can expect a maintenance interval of 50 years or more according to tests, there is additionally the possibility over the entire service life to retighten the arrangement.

 To realize the bias, a free length of the anchoring rod is required, in which an unrestricted pre-strain can be imposed. For this purpose, according to the invention surrounded above the involvement in the concrete of the structure of the anchoring rod with a material that prevents the frictional connection between the anchoring rod and the potting material that is installed between the base plate and structural concrete. In the footplate, this is geometrically ensured by a corresponding size of the holes / holes in the plate.

In a variant of the invention - the continuous anchoring of the concrete structure, in which no force is required over an anchoring length in the building by bonding between anchoring rod and concrete - the free stretch length can be in the component. Here is the installation of a Hüllroh- Res, which is filled with suitable material, an alternative to the mere encasing of the anchoring rod.

 The cladding material must be sufficiently extensible not to hinder the change in length of the anchoring element in the course of the bias. It has been shown that certain types of bitumen are very suitable.

 Prestressed connections require special attention with regard to corrosion protection. This results in a further requirement for the cladding material: it must ensure corrosion protection. As a rule, the anchoring elements are galvanized / pretreated, so that there must be no material incompatibility between the alloy and the cladding material. Also, a resistance to the surrounding material mortar and its alkaline properties is necessary. Furthermore, a high degree of diffusion-tightness is required, which also withstands the dynamic stresses (vibrations). For this purpose, especially materials are suitable, which - like bitumen - crawl though with permanent force effect, however, respond elastically with short-term force.

 Surprisingly, products which are otherwise used in a completely different field of construction, namely for the sheet pile wall sealing, have proven to be particularly favorable for durable embedding.

With regard to the corrosion issue - especially the stress corrosion cracking in toughened steel - it has surprisingly been found advantageous to form the anchor rod in a lower strength class - which is associated with a lower sensitivity to hydrogen-induced stress corrosion cracking - as the mother: especially a choice of material with the Material strength marking 8 (galvanized fine grain steel), better still 8.8, or material number 1.4571 (stainless steel) for the threaded rod, material number 1 .4571 (stainless steel) for spherical disc and conical socket and material number 1 .4401, strength marking 10 ( galvanized fine grain steel), even better 10.9, for the mother (system HV, factory lubricated) has proved to be advantageous. The material identification numbers refer to common names in Europe, while analogous materials are to be used in non-European countries. According to one embodiment of the invention, the mounting element comprises at least four anchors, which are assembled by means of cross connection bars to form a structural unit. This requires before pouring the concrete of the structure or foundation to be positioned only a mounting element on which all the necessary for the attachment of the post threaded portions are formed. Alternatively, it is also possible that several - at least four -inclusive elements, which only comprise individual anchors, are provided. Such an arrangement is to be preferred if the installation elements are to be fastened by gluing in the concrete body or anchored by complete anchoring of the concrete body.

In order to bond the installation elements particularly well to the concrete, it is advantageous that the anchors have a section made of a ribbed steel - in this case the usual structural steel Bst 500S has proven to be sufficient. The threaded portion for screwing the fastening nut is usually formed on the anchor and thus designed in one piece with this. Alternatively, however, it is also possible that the threaded portion is formed by a Gewindebol- zen, which is screwed into a threaded bore of an armature formed on the sleeve portion.

A variant of the invention, which further increases the stability of the post anchoring, provides that the threaded bolts / threaded rods do not protrude perpendicular to the base plate of the anchoring element down into the concrete, but by an angle δ, which is between an angle ε and ß (ε <δ <ß), slightly inclined outwards. The angle δ results from the dimensions of the base plate, the height of the Fußplattenunterfütterung and the material thereof.

The parallel alignment is not the ideal nominal state. Rather, the armature / threaded rods should also have an inclination to the outside when using the system ball disc / cone, so that the tensile force acts on vibration of the post parallel to the screw axis.

So far, the finite thickness of the foot plate and the page has not been considered. Although the system spherical disc / conical pan evened out the

 Forces on the circumference of the mother, but it does not eliminate the

horizontally acting forces are due to the fact that the foot plate and the peg have a finite thickness and the fastening nut holds the foot plate at the top of the foot plate, whereas the (virtual) fulcrum on the other side the edge of the underside of the footplate, or even at the bottom of the pageis. Depending on the elasticity of the base plate and the piling material, it can even be pushed further inwards from the outer edge, for example to the outer edge of the spacer element described later in the text, so that the horizontal forces are even greater.

 Figures 6 and 7 with exaggerated dimensions, in the sake of clarity, only the attachment is drawn on one side, illustrate this.

 Ideally, therefore, runs an anchor / threaded rod with one to one

Angle δ inclined to the vertical direction. (Due to the thickness of the foot plate / the side, the angle moves in the region of 5 degrees, so it is not negligible.) The threaded rods are then no longer as parallel to each other as before. The angle is dependent on the elastic properties of the materials between the angles ε and ß in the figures, due to the materials used in most cases often at ε, so that then ε can be chosen as a good approximation (due to manufacturing tolerances ε ± 30%).

 If a is the distance of the fastening nut to the opposite edge of the base plate, b the distance of the fastening nut to the opposite edge of the spacer, c the thickness of the base plate and d the height of the spacer or the potting compound, then applies to a good approximation for the critical angle ε and β: tan ε = c / a tanβ = (c + d) / b

To align the footplate to the effect that the post is oriented in the desired position, usually the vertical, it is proposed that a spacing element be arranged between the footplate and the concrete body, which is preferably located in a centroid of the footplate. The space between the foot plate and concrete body around this spacer is filled with a layer of low-shrink mortar or other suitable potting compound. An embodiment of the invention is explained below with reference to the drawings. The schematic figures show:

Fig. 1 a pre-fabricated from several anchors, cast-in mounting part, for attachment of posts of the protective wall

Fig. 2 is a made of individual, subsequently drilled and glued anchors connection, for attachment of posts of the protective wall Fig. 3 is a single, subsequently introduced in continuous boreholes anchors connection, for attachment of posts of the protective wall

Fig. 4 is a designed as a single anchor mounting element in an enlarged Dar- position

Fig. 5 is a sectional view of a conical socket and an aligned spherical disc with threaded portion and nut Fig. 6 is a rough sketch, in which the force acting on a threaded rod and fastening nut force is shown at a sideways movement of the post at hard pillage

7 shows a rough sketch in which the force acting on a threaded rod and fastening nut is shown in the case of a sideward movement of the post in the case of a flexible pagel

FIGS. 1 to 3 show a detail of a concrete structure 1-for example, the cap area of a bridge. The prefabricated installation element is preferably embedded in the concrete body 1 or durchge anchored, but it is also possible to attach this by gluing. On the concrete body 1 is a post 3, which is preferably made of steel and is provided with a foot plate 4, which serves to be fastened to the mounting element. This attachment will be discussed in more detail below. At the post 3, the protective walls are attached. 1 shows a built-in part consisting of at least four anchors 5, each anchor 5 comprising a section 6 to be anchored in the concrete, for example of a ribbed steel (BSt 500S) and a threaded section of stainless steel 7. The anchors 5 are arranged substantially parallel and joined together via steel connecting rods 2 to form a structural unit with a defined spatial configuration, in particular welded together. The installation element shown is poured in the course of building construction in the concrete body 1, with the post mounting galvanized threaded bolt 8 or threaded bolt of non-Stendern steel 8 'are screwed into the threaded portion of stainless steel 7. Alternatively, threaded bolts 8 'can already be welded to the installation element in advance. The galvanized threaded bolt 8 is above the building concrete 1 - in the mortar layer 13, the foot plate 4 and the conical-spherical disk system 9, 10 - provided with a Bitumendickbeschich- device 15 to ensure the free preload length and corrosion protection. Surprisingly, it was found that without additional bituminous coating, the corrosion protection by otherwise proven galvanizing under these boundary conditions (lack of aeration, prestressing) is insufficient.

FIG. 2 shows a section through a device held in a concrete body 1 with a post 3 attached thereto. Several individual mounting elements 5 are anchored in the concrete body 1, for example, fixed by gluing. In the sectional view, only two of the at least four components 5 can be seen. Each anchor 5 consists of a longer section of reinforcing steel BSt 500S 6 for anchoring in the concrete body 1 and a threaded portion made of stainless steel 8 ', which protrudes from the concrete body 1. In the area of the mortar bed 13, a bitumen thick coating 15 is applied, which prevents the non-positive bond between the thread 8 'and the mortar bed 13. The threaded bolt 8 'made of stainless steel requires no further corrosion protection - so that can be dispensed with the Bitumendickbeschichtung 15 in the footplate 4 and the conical-spherical-disc system 9, 10.

Fig. 3 shows a section with a variant in which the concrete body 1 is completely durchankert. In subsequently manufactured boreholes are galvanized

Threaded rods 8, which are provided with a bitumen thick coating 15, a brought and on component top and bottom side with an arrangement of balancing device 9, 10 and nuts 1 1, 12 biased.

The post 3 in FIG. 3 has, as in FIGS. 1 and 2, a foot plate 4 which is provided with bores through which the threaded sections 8, 8 'of the anchors 5 extend. Below the foot plate 3 is a spacer element 14, for example a plastic spacer block, wherein the spacer element 14 is arranged at least approximately in the centroid of the base plate 4. Around the spacer 14 around the space formed between the concrete body 1 and the base plate 4 is filled with a layer of mortar or grout 13.

On the threaded portions 8, 8 'of the armature 5 are galvanized nuts 11 1 made of high-strength steel with the interposition of a compensating device 9, 10 by means of which the base plate 4 against the concrete body 1 and the compensation layer 13 (pre-) is stretched. An additional safeguard against loosening this connection is made with a loss-locking nut 12 made of stainless steel. This lock nut 12 is not countered against the nut 1 1! It is only with a tightening torque of 5 to 20 Nm, preferably about 10 Nm, screwed in the same direction, without the nut 1 1 would screwed against it. The application of this Anziehmomentes takes place only after the second tightening of the nut 1 1, otherwise the effect of the mother 1 1 is hindered. The unspecified in Fig. 1 and 2 attachment of the base plate 4 on the concrete body 1 is also done with nuts 1 1, 12 of threaded portions 8, 8 'of the armature 5 with the interposition of balancing devices 9, 10, as indicated in Fig. 3 is. The compensation device 9, 10, which will be explained in more detail later, makes it possible - within certain limits - to compensate for skewed angle deviations from the longitudinal axes of the anchor. As a result, a centric load introduction of the clamping force generated by the clamping of the nut 1 1 on the threaded portion 8, 8 'in the armature 5 is achieved. An angle deviation α caused by manual work on the construction site in the manufacture of the concrete structure or concrete body 1 is shown in FIG. The mounting elements 5 are preferably made of stainless steel or galvanized steel and are cast or glued in the concrete or possibly durchgeankert. Subsequently, the post 3 is placed with its base plate 4, so that the threaded portion 8, 8 'of each armature 5 is guided by corresponding holes in the base plate 4. In the case of the embodiment with galvanizing the threaded portion 8 is additionally provided with a Bitumendickbeschichtung 15. In order to maintain a distance required for the alignment of the post 3, the spacer element 14 is placed under the base plate 4, if possible in the centroid of the base plate 4.

Alternatively, the spacer element 14 is already fixedly mounted below the base plate 4, so that an additional adjustment to the centroid and eliminates the risk of slippage of the spacer 14 during installation of the post 3 no longer exists.

 The post 3 can thus be pivoted with respect to its longitudinal axis in any direction, in order to achieve an exact alignment with the desired position. This is followed by an intermediate fuse with the nuts 1 1. Then, the free space between the base plate 4 and the concrete body 1 is filled with a potting compound or mortar around the spacer element 14, whereby the layer 13 results. After hardening of the potting layer 13, the nuts 1 1 are loosened and the area of the galvanized threaded rod 8 is coated with bitumen after the already existing coating 15 to below the cone-and-ball system 9, 10. With the interposition of the balancing device 9, 10, the high-strength, galvanized nuts 1 1 are screwed again and biased. Finally, the loss-securing nut 12 is attached for additional securing of the connection.

4 shows a single anchor 5, which comprises a section 6 of BSt 500S for anchoring in concrete and a threaded section 8, 8 '- either with hot-dip galvanizing or stainless steel - for screwing the nuts 1 1, 12 comprises. The section 6 is designed at least over part of its longitudinal extent as a ribbed steel in order to achieve the best possible positive connection with the concrete or adhesive.

In Fig. 5, the balancing device 9, 10 is shown in section, wherein the compensating device 9, 10 comprises a conical socket 9 and a ball disc 10 mounted thereon. These components are defined with respect to their shape in DIN 6319. In the illustration, the compensating device 9, 10 led threaded bolt 8 whose longitudinal axis LA2 inclined by the angle α to the system axis. On the aligned with the post 3 in Fig. 1, 2 and 3 base plate 4, the conical socket 9 is placed, whose axis LA1 runs parallel to the system axis of the post. To compensate for the inclination of the threaded portion 8, the spherical disk 10 is pivoted on the conical socket 9, so that the longitudinal axis LA2 of the spherical disk is identical to the longitudinal axis LA1 of the threaded portion 8 of the armature. Due to the pivoted-up spherical disk 9, a force introduction surface extending parallel to the clamping surface of the hexagonal nut 11 is provided, so that the load bearing is ensured exactly in the longitudinal direction of the armature 5 of the installation element. The angle between the longitudinal axes LA1 and LA2 is denoted by α.

In Fig. 6 is a rough sketch of the effect of a sideways movement of the post 3 to the right on the force relationships on a threaded rod / bolt 8, 8 'and fixing nut 1 1 for the case of an ideal hard potting compound 13 is shown. (The other fixtures are omitted for clarity.) Virtual pivot is then D.

 If the potting compound 13 has properties such as those of the foot plate 4, the virtual fulcrum E would be.

The acting force F results according to parallelogram of forces.

In Fig. 7 is a rough sketch of the effect of a sideways movement of the post 3 to the right on the force relationships on a threaded rod / bolt 8, 8 'and fixing nut 1 1 for the case of a flexible casting compound 13 and an ideal hard spacer element 14 shown. (The other fixings are omitted for clarity.) Virtual pivot is then G.

The acting force F results here also according to parallelogram of forces. LIST OF REFERENCE NUMBERS

1 concrete structure / body

 2 built-in element - cross connection bars 3 posts

 4 foot plate

 5 anchors

 6 Anchoring ribbed steel (BSt 500S) 7 Thread section - here: female thread 8 threaded section / bolt, galvanized 8 'threaded section / bolt, stainless

 stole

 9 conical pan

 10 spherical disc

 1 1 hexagon nut (galvanized, high-strength steel, factory pre-lubricated)

 12 loser lock nut

 13 potting compound layer

 14 centering / spacer

 15 bitumen thick coating

Claims

CLAIMS Fixing the posts (3) of protective walls on concrete structures (1) or foundations, which has the following characteristics:

 in the concrete body (1) at least one anchor element (5) is provided which is either cast, glued or durchge anchored and to which a foot plate (4) of the post (3) is attached

 the anchor element (5) introduces the load from the effects on the protective wall into the structure (1), threaded bolts (8, 8 ') being passed through the base plate (4), which are connected to the anchor element (5) and the by means of a conical cup-spherical disk system (9, 10) and a nut (1 1) centrically guide the force in the anchoring element (5)

the connection is determined with a defined and with respect to the - during the life of the building - occurring effects determined biasing force and additionally secured with a loss-lock nut (12), which is not countered against the underlying nut (1 1), but with a Tightening torque of 5 to 20 Nm, preferably 10 Nm is screwed in the same direction, this tightening torque is applied only after the second tightening of the nut (1 1) the free tensioning path on the threaded bolt (8, 8 ') is surrounded at least between the bolt (8) and potting compound (13) with a viscoelastic coating (15) to prevent adhesion, so that the expansion is not hindered

2. Fastening according to claim 1,

 characterized in that the nuts (1 1) in the period of 1 day to 7 days after production of the potting compound (13) under the base plate (4) are attracted with 75% of the required according to plan tightening torque, then that after 7 days with 100 % of the construction plan necessary tightening torque are tightened

 and that they are tightened 6 months after the production of the potting compound (13) with 100% of the required according to construction plan tightening torque.

3. Attachment according to claim 1,

 characterized in that the nuts (1 1) are tightened in the period of 7 or more days after production of the potting compound (13) under the base plate (4) with 75% of the required according to plan tightening torque, that they then 1 to 3 weeks after this first tightened with 100% of the required according to the blueprint tightening torque are tightened

 and that they are tightened 6 months after the production of the potting compound (13) with 100% of the required according to construction plan tightening torque.

4. Attachment according to at least one of claims 1 to 3,

characterized in that it contains threaded bolts (8, 8 ') of quality 8.8, which are after application of the final bias under a bias between 25 and 120 kN, preferably between 60 and 90 kN, stand.

5. Attachment according to claim 4,

 characterized in that the nuts (1 1) are tightened with tightening torques between 100 and 550 Nm, preferably between 250 and 400 Nm.

6. Device according to at least one of claims 1 to 5,

 characterized in that the material for coating (15) is a bitumen which has the property of not attacking zinc and stainless steel over the life of the structure and moreover serving for corrosion protection.

7. Apparatus according to claim 6,

 characterized in that the coating material (15) is a bitumen commonly used for a sheet pile lock seal.

8. Device according to at least one of claims 1 to 7,

 characterized in that a galvanized, high strength steel is used for the threaded bolt (8) whose strength is below that of the galvanized hex nut (1 1) to reduce the sensitivity of the tension members against stress corrosion cracking.

9. Device according to at least one of claims 1 to 8,

 characterized in that the free clamping path in the core of the concrete component (1) extends within a cladding tube, and that the gap between the cladding tube and bolt (8) with a viscoelastic material to prevent the frictional connection between the bolt (8) and concrete body (1) is filled , whereby an extension of the bolt (8) is not hindered.

10. Device according to at least one of claims 1 to 9, characterized in that the material for filling the cladding tube is a fat.

1 1. Device according to at least one of claims 1 to 10,

 characterized in that in the case of the use of galvanized bolts (8) the Bitumendickbeschichtung (15) for reasons of corrosion protection to below the compensating element (9, 10) is guided.

12. Device according to at least one of claims 1 to 1 1,

 characterized in that in the case of using bolts (8 ') made of stainless steel, the Bitumendickbeschichtung (15) only in the region of the mortar layer (13) is mounted.

13. Device according to at least one of claims 1 to 12,

 characterized in that the threaded bolts (8, 8 ') not perpendicular to the base plate (4) protrude down into the concrete, but by an angle δ, which is between an angle ε and ß (ε <δ <ß), slightly behind are inclined on the outside, wherein for the angle ε and ß applies:

 tan ε = c / a

 and

 tanβ = (c + d) / b

14. Device according to claim 13,

 characterized in that the threaded bolts (8, 8 ') are inclined slightly outwards by the angle ε ± 30%.

15. A method for producing a long-term maintenance-free attachment of posts (3) according to at least one of claims 1 to 14, characterized in that the nuts (1 1) in the period of 1 day to 7 days after production of the potting compound (13) under the base plate (4) are attracted with 75% of the required according to plan tightening torque that they then after 7 days with 100 % of the tightening torque required by the blueprint

 and that they are tightened 6 months after the production of the casting compound (13) with 100% of the necessary according to the blueprint tightening torque, or

 that the nuts (1 1) are tightened in the period of 7 or more days after production of the potting compound (13) under the base plate (4) with 75% of the required tightening torque according to the blueprint,

 that they are then tightened 1 to 3 weeks after this first tightening with 100% of the necessary according to the plan tightening torque

 and that they are tightened 6 months after the production of the potting compound (13) with 100% of the required according to construction plan tightening torque.

16. The method according to claim 15,

 characterized in that after retightening the nut (1 1) a loss-lock nut (12) is screwed, which is tightened with a tightening torque of 5 to 20 Nm, preferably about 10 Nm, without countering the nut (1 1).