SK2282000A3 - Device and method for reducing the bowing of a component which is subject to a load - Google Patents

Abstract

The invention relates to a device and a method for reducing the bowing (w) of a component (1) which is subject to the force (9) of a load, said bowing (w) being in a transversal direction in relation to the longitudinal axis (7) of the component (1). A spacer (21) engages at a pressure point (26) on a front surface (23) of the component (1), hereby keeping the distance between said pressure point (26) and a support structure (24) constant. The pressure point (26) is located on the front surface (23) of the component (1), beyond the neutral fibres (11).

Description

Method and apparatus for reducing the deflection of a loaded component

Technical field

BACKGROUND OF THE INVENTION The present invention relates to a device for reducing the deflection of a structural component subjected to load forces, in particular a longitudinal rib of a condensing tower of a nuclear power plant, wherein the deflection occurs in a direction perpendicular to the longitudinal axis.

The invention further relates to a method for reducing the deflection of a structural component subjected to loading forces, in particular a longitudinal rib of a condensing tower of a nuclear power plant, wherein the deflection occurs in a direction perpendicular to the longitudinal axis of the structural component. value.

The invention also relates to a spacer for reducing the deflection of a component subjected to loading forces, in particular a longitudinal rib of a condensing tower of a nuclear power plant, wherein the deflection occurs in a direction perpendicular to the longitudinal axis of the component.

BACKGROUND OF THE INVENTION

DE-PS 803 243 discloses a method for lifting a bridge and ceiling beam in the middle part of its span. In this way, during the installation of the bridge or ceiling, that is to say, before the application of the loading forces directed downwards, the bridge or ceiling support structure is folded up. The bend is formed by applying a tensile stress to the upper side of the bridge or ceiling facing the next structure, while the lower side of the bridge or ceiling is connected to the other structure by means of a spacer. This additional structure is, for example, another bridge or ceiling field or another structure.

DE-OS 1 959 668 describes a method of mounting a beam and a device for clamping a beam. In this assembly procedure, the beam is folded before loading so that its tensile fibers are elongated only to the elastic limit. This predetermined deflection is produced by means of rods which are engaged on the underside of the beam and cause a deflection which is directed upwards, in contrast to the deflection induced by the application of the load forces. The beam is then supported on its upper side by a stop member on the surrounding structure surrounding the ends of the beam. As a result of this pre-induced deflection, the change in deflection induced by the application of load forces is less than would be the case with a beam without this prestressing. A disadvantage of the assembly process according to DE-OS 1 959 868 is that the elastic region of the beam material must be large enough to produce the necessary pre-bending. A further disadvantage is that, in some constructions, preliminary reverse bending is not permitted, for example for safety reasons. In addition, the beam and the surrounding structures must be adapted to absorb the high forces that occur during such prestressing, so that this assembly procedure can only be carried out to a very limited extent with already installed beams.

In an Eastern European-type nuclear power plant, a condensation tower, also called a barbotage tower, is used to equalize the pressures needed in the event of a failure. In this tower is created water supply in multi-storey tanks, created in the form of metal cabinets. These metal cabinets are, inter alia, a floor plate and a ceiling plate which are supported by a set of longitudinal supporting ribs. These longitudinal ribs are fixed at both ends to double T-shaped beams extending perpendicular to the longitudinal axis of the ribs and forming the base grid of the condensation tower.

The metal chambers are sized to a certain pressure prevailing in their interior. To increase the safety of such a nuclear power plant, it is necessary to dimension the condensation chamber to a higher pressure. However, at elevated internal pressure, the sheathing sheets, together with the respective supporting longitudinal ribs, may bend to an excessive and unacceptable extent. The bend has its maximum size approximately in the middle of the span of the longitudinal ribs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device for reducing the deflection of components which are subjected to load forces and which are formed by longitudinal ribs supporting the casing sheets of the chambers in order to increase the stability of the components. For the same purpose, it is also necessary to propose a method for reducing the deflection of building components. In this case, the apparatus for carrying out this method without pre-bending should also be dispensed with as a method of reducing the fold.

SUMMARY OF THE INVENTION

This object is achieved by a device of the type according to the invention, characterized in that the device is provided with a spacer resting against the end face of the longitudinal ribs at the bearing point, while maintaining the distance of the bearing point from the support structure at a constant size. the position is located on the front face on the side of the neutral filaments at which the longitudinal ribs are folded to extend their length.

In the case of bodies rotationally symmetrical about the longitudinal axis, the abutment point should preferably be located eccentrically on their end faces.

Thus, the stability of the component is not improved by improving the properties of the material used, for example flexural tensile strength, but in particular by the fact that the female of at least one face of the component is pegged and maintained by the spacer. The effects of the described device do not begin to appear until the assembled state of the components, that is, only after the support structure has been formed.

Neutral tensile forces causing elongation and compressive stresses causing compression do not occur in the neutral fibers of the component.

The location of the bearing points outside the neutral fibers of the bent beam means that the spacer, and in particular its longitudinal support force, is applied to the component resulting from the additional opposite bending moment having the opposite meaning to that generated by the loading forces causing the deflection. By applying an additional bending moment, the total deflection of the component is reduced.

Usually, on the folded components, there is on the one hand a neutral fiber for compressing the material and, on the other hand, for extending the material. Compression causes compressive stress and elongation leads to tensile stresses in the building component. The elongation is simply counteracted by applying pressure to the end faces of the component by means of a spacer. Thus, the pressure loaded spacer can advantageously be retained by clamping or fitting between the component and the support structure without the need for a joint, for example a pressure-resistant weld joint, between the spacer and the component as well as the spacer and support structure. In the devices according to the invention, the spacer can be mounted simply and quickly.

Such a connection would be necessary if the spacer were to be loaded with the same high force but acting in the opposite direction, i.e. pulling, which would be necessary if the bearing seat were on the side of the neutral fiber that occurs when folded component for longitudinally compressing material.

The force with which the component is loaded may be a transverse loading force acting perpendicular to the longitudinal axis of the component, also a longitudinal loading force causing the component to be deflected by the buckling pressure.

With the described device according to the invention, it is possible to advantageously improve the stability of the component without the need to attach additional stabilizing elements to the longitudinal side or to the longitudinal sides of the component. A particularly important advantage of the solution according to the invention is that the stability is improved by acting on the faces of the component. In fact, the longitudinal sides of many components are not freely accessible and must therefore be kept free by special measures, or they must be provided in accessible places with retaining elements carrying the component whose deflection is to be reduced.

The support structure may preferably be formed by an adjacent component of the same embodiment.

In a condensation tower of this kind, the longitudinal ribs belonging to two adjacent sheet metal chambers are disposed along a common thought axis. A gap exists between the two adjacent longitudinal ribs at the point where they are attached to the common double T-shaped longitudinal beam. In such a case, the spacer is positioned, for example, in this gap and abuts the faces of both longitudinal ribs.

In a further preferred embodiment of the invention, at least under the action of the loading forces by the spacer, a longitudinal support force is approximately approximately parallel to the longitudinal axis of the longitudinal component and acts on the abutment point. The longitudinal abutment force is a forced force by which the component is kept at a bearing point at a constant distance from the abutment structure. Due to the force exerted in this way, the limit conditions for the deflection of the component are varied so that the maximum deflection is less under the action of the same load forces.

The condensation tower spacer according to another preferred embodiment of the invention comprises two end pieces connected together by a threaded rod fixedly lockable at an adjustable constant minimum distance from each other. The minimum spacing is given, for example, by the spacing between the end faces of the components that occurs in the unloaded state. The deflection limiting device thus formed provides the advantage that it can be easily and quickly adjusted to another minimum distance between the opposing members or the distance between the building component and the support structure.

The spacer is preferably retractable or clamped into the longitudinal rib and / or the support structure, or may be clamped in these connecting elements. These structural modifications are particularly advantageous for components with pressure-bearing spacers. By inserting or gripping, for example, in prepared recesses in the component and / or support structure, the need for expensive welding joints is eliminated and the spacer can very easily be released and removed again.

The stated task of reducing the deflection of a loaded component is also solved by a method of the kind according to the invention, which consists in maintaining a constant distance between the end face of the building and the support structure and the end face of the building. , which occurs in the component during its folding for longitudinal extension.

A spacer is used to support it, the expansion being achieved by turning the screw nut on the threaded rod of the spacer.

The device comprising the spacer according to the invention can also be used to solve the problem, the principle being that the spacer comprises two end pieces connected together by a threaded rod and secured at an adjustable constant minimum distance.

In a preferred embodiment of the invention, the spacer is retractable or clamped into the component and / or the support structure.

Spacer is a simple and effective technical means for carrying out the process of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be elucidated in more detail by way of example embodiments illustrated in the drawings, in which:

Fig. 1 shows a schematic side view of a component without the device according to the invention, subjected to the loading forces, FIG. 2 shows a schematic side view of a component with the device according to the invention, subjected to a load and provided with a spacer, and FIG. 3 shows a section from the example of FIG. 2, in which the spacer according to the invention is shown in more detail.

DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 shows, in a side view, an elongated component 1, which is fastened at both its ends by a weld seam 2 shown in each case on a beam 3 on which it is supported. The component 1 in this exemplary embodiment is a longitudinal rib in a condensation cooling tower of nuclear power plants with a structure used in Eastern Europe. The longitudinal ribs serve to support the abutment plates (not shown) forming the individual water chambers. The inner space 5 of the sheet metal chambers, filled with water and acting under load forces, is shown only schematically with its lower part without side walls and without sheets. The beams 3 together with the other beams (not shown) form the base grid of the condensing cooling tower.

The load-bearing forces 9 are applied perpendicularly to the longitudinal axis 7 of the component 1. The load-bearing forces 9 directed from the top downwards are exerted by the water pressure acting on all sides inside the metal chambers 5, they are not so lone forces acting at individual points 1, but extend over its entire length. Due to the load forces distributed in this way, the component 1 folds perpendicular to its longitudinal axis 7. The fold 13 of the component 1 is shown schematically and in an exaggerated scale at the bottom of FIG. 1, wherein the component 1 is illustrated by two lines of which the upper line shows the state of the component 1 in an unloaded state and the lower line shows the folded component 1 with a fold w. The deflection w reaches its maximum deflection value wo approximately in the middle of the length of the component L

In FIG. 1 also indicates the course of the neutral fiber 11 of the component 1. The neutral fiber 11 is generally referred to as the line or surface of the component 1 in which there are no tensile forces or compressive forces directed in the longitudinal direction. The neutral fiber 11 may be located off-center in the longitudinal direction off-center in the cross-section of the asymmetrical component 1, as shown in FIG. First

Fig. 2 shows a component 1 and a beam 3 of a similar embodiment as in FIG. 1, but with the difference that with both faces 23 of the component 1, one spacer 21 is always engaged. Each spacer 21 is supported on the side facing away from the component 1 on the support structure 24. By acting of the spacer 21 on the faces 23 of the component 1 deflects w at the same high load forces 9 as compared to the example of FIG. 1 shrinks. As shown in FIG. 2, again schematically and shown on a larger scale, the deflection w approximately in the middle of the span of the component 1 reaches its maximum deflection value wA. In particular, this maximum value of wA of the deflection is reduced (wA W0) compared to the previous example in which no spacer 21 acts.

In FIG. 3 is a detail of FIG. 2, with no load forces 9.

detail does not affect the component 1

Under the action of the loading forces 9 shown in FIG.

2, the positions of the end faces 23 of the component 1 would change.

This deformation also occurs due to the limited stiffness and torsion resistance of the beam 3. If the component 1 is not provided with any spacer 21, the end face 23 below the neutral axis 11, i.e. on the side facing away from the applied loading forces 9, will start to be applied by the loading forces 9 due to the resulting deflection and / or longitudinal extension of the pull region. on the contrary, over the neutral axis 11, the end face 23 would be somewhat distant from the support structure 24 due to the resulting folding and / or longitudinal extension.

In the example shown in FIG. 3, the support structure 24 is formed by an adjacent component of the same type as the component 1, which is also subjected to a load under load in the inner space 5 of the sheet metal chamber or other loading forces (not shown), all being applied from above. The support structure in this example is also connected by a weld seam 2 to the beam 3. The end face 25 of the support structure 24, facing the component 1, would therefore tend to change its position under load forces similar to the end surface 23 of the component 1. Z The resulting approach of the end faces 23, 25 of the component 1 or of the support structure 24 is prevented by the spacer 21 in the solution according to the invention. The spacer 21 abuts the front surface 23 of the component 1 at the abutment point 26 below the neutral axis 11. on the end face 25 of the support structure 24 at the second abutment point 27, located below the neutral fiber 11. The spacer 21 applies a bending moment to the component 1 and to the support structure 24 which counteracts the deflection of the component 1.

The spacer 21 consists of two substantially planar end portions 28A, 28B or end plates which are held by a threaded rod 29 spaced apart. The first end piece 28A is connected by a weld seam 30 to the threaded rod 29. The second end portion 28B is inserted into an opening formed in the region of the seating location 26 for the threaded rod.

29th

By means of a nut 31 screwed onto the threaded rod 29, a predetermined minimum distance between the end pieces 28A can be manually set. 28B. Through the hole in the second end piece 28B, the threaded rod 29 is pushed through and its protruding section is embedded in the cavity of the component 1 The screw nut 31 pushes through the washer 32 onto the second end piece 28B.

The spacer 21 is clamped by a pair of centering pieces 40 in each recess in the component 1 or in the support structure 24. The spacer 21 is mounted to its end position without the need for weld seams between the first end portion 28A and the support structure 24 or between a second end piece 28B and a component 1.

ZZ8-

Claims (9)

PATENT CLAIMS 1. A condensing tower of a nuclear power plant having a support structure (24) and longitudinal ribs (1) subjected to loading forces (9) causing a deflection (w) of the longitudinal ribs (1) in a direction perpendicular to their longitudinal axis (7), characterized in that it is provided with a spacer (21) supported in the abutment point (26) on the end face (23) of the longitudinal ribs (1), and under load the distance between the abutment point (26) and the support structure (24) is sustainable at a constant size and the abutment point (26) is located on the face (23) sideways of the neutral filament (11) at which the longitudinal ribs (1) at the fold (w) extend for length. Condensation tower according to claim 1, characterized in that the support structure (24) is formed by an adjacent longitudinal rib (1). Condensation tower according to claim 1 or 2, characterized in that the spacer (21) is capable of transmitting, at least under the application of the load forces (9), a longitudinal support force approximately parallel to the longitudinal axis (7) of the longitudinal rib (1). 26). Condensation tower according to one of Claims 1 to 3, characterized in that the spacer (21) comprises two end pieces (28A, 28B) connected together by a threaded rod (29) and secured in an adjustable constant minimum distance from each other. Condensation tower according to Claims 1 to 4, characterized in that the spacer (21) can be inserted or clamped into the longitudinal rib (1) and / or into the support structure (24). Method for reducing the deflection (w) of a component (1) subjected to loading forces (9), in particular a longitudinal rib in a condensing tower of a nuclear power plant, wherein the deflection (w) arises from a bent state transversely to the longitudinal axis (7) 1) and extends in the direction of application of the load forces (9) and the component (1) is supported such that the distance of the component (1) from the support structure (24) is kept constant, characterized by maintaining a constant distance the location (26) on the face (23) of the component (1) from the support structure (24) and the location (26) on the face (23) is located on the side of the neutral fiber (11) of the component (1) occurs when the component (1) is folded for longitudinal extension. Method according to claim 6, characterized in that a spacer (21) is used for the support, the expansion being achieved by turning the screw nut (31) on the threaded rod (29) of the spacer (21). Spacer (21) for reducing the deflection (w) of a component (1) subjected to loading forces (9), in particular a longitudinal rib in a condensation tower of a nuclear power plant, the bending (13) being perpendicular to the longitudinal axis (7) of the building a member (1) comprising two end pieces (28A, 28B and one threaded rod (29), characterized in that one of the end pieces (28A) is welded to the threaded rod (29) and the other end piece (28B) is slid onto the threaded rod (29) such that the end portions (28A, 28B) are securely locked by a threaded nut (31) screwed onto the threaded rod (29) at an adjustable constant minimum spacing. Spacer (21) according to claim 8, characterized in that it is slidable or clamping into the component (1) and / or the support structure (24).