DEVICE FOR SECURING AN UPSTANDING ELONGATED ELEMENT AT ITS LOWER END TO THE UPPER SURFACE OF A PEDESTAL

Abstract: A device for securing an upstanding elongated element such as a column (1), pole or chimney at its lower end to the horizontally extending upper surface of a pedestal, comprising a flange-shaped means (3) to which, near its one terminal edge the lower end of the element (1) is secured, and which is disposed in spaced apart relation with the upper surface of the pedestal (9), and upon which it rests freely, with its terminal edges on the upper surface of the pedestal, through at least one pair of support members, which are spaced apart in radial direction, means (11, 11') being provided which are in engagement with said pedestal (9) for excerting at least one prestressing force on said flange-shaped member (3) so that said member (3) is pressed against the pedestal (9) through the support means (11, 11'), which means is preferably formed by at least one pre-stressed vertical extending rod (11) which is in engagement at the one side with the flange-shaped means (3) at a point disposed between the support means and at the other side with the pedestal (9). Advantageously said support means are formed by wedge-shaped members which are disposed between the upper surface of the pedestal (9) and protruding elements (4, 5) fixed to the flange-shaped member (3).

Description: Device for securing an upstanding elongated element at its lower end to the upper surface of a pedestal. The invention relates to a device for securing an upstanding elongated element such as a column, pole or chimney at its lower end to the upper surface of a pedestal in which the lower end of the element is fixed to a flange-shaped means extending substantially radially and said flange-shaped means is fastened to the pedestal. In such a securing device in particular attention has to be paid thereto that when said element is loaded by an external load e.g. by wind pressure, tensile stresses are generated in said element which have to be taken up by the securing means at the pedestal. Up till now the flange-shaped means is fixed directly to the pedestal in plannar engagement with said pedestal, by means of fastening means, in particular in a pedestal formed by a plate of concrete, by means of fastening-bolts embedded in the concrete. This means that in the occurance of tensile stresses in the upstanding element, the fastening means in particular the fastening-bolts are subjected to high varying loads sothat there is the danger that said bolts collapse or are pulled loose from the concrete. Moreover large bending moments can develop in the flange-shaped means which make it essential that mounting plates are provided between said flange-shaped means and said upstanding element to oppose distortions, so that the securing device becomes complicated. The object of the invention is to provide an improved device of the above mentioned type. This object is attained in that in the device according to the invention the flange-shaped means disposed in spaced apart relation with the upper surface of the pedestal, rests freely adjacent its terminal edges on the upper surface of the pedestal through at least one pair of support members which are spaced apart in radial direction and that means are provided which are in engagement with said pedestal for excerting at least one pre-stressing force on said flange-shaped member so that said member is pressed against the pedestal through the support means. Preferably said means for excerting a pre-stressing force are formed by at least one pre-stressed vertical extending rod which is in engagement at the one side with the flange-shaped means at a point disposed between the support means and at the other side with the pedestal. In this way a relative large upwardly directed reaction force acting on the flange-shaped means is developed by the pre-stressing force at the support means which is disposed adjacent the fastening of the upstanding element to the flange-shaped member so that when tensile stresses are developed in the upstanding element said stresses lead exclusively to a decrease of said reaction force which force can be chosen so large that it will never completely disappear with the result that the pre-stressing means which are in engagement with the pedestal will never be exposed to varying loads and that no bending moments will be formed. In order to make said reaction force as large as possible with a predetermined pre-stressing force, preferably the point where the pre-stressed rod is in engagement with the flange-shaped means is disposed off-centre between the support means and closer to the support means adjacent which the upstanding element is secured to the flange-shaped member. Advantageously each pre-stressed rod extends slidably through the pedestal and the flange-shaped member and each pre-stressed rod is in engagement with the lower surface of the pedestal and with the upper surface of the flange-shaped member. Preferably the pedestal is formed by a slab of concrete in which, according to the invention, in its upper- and lower surface a washer is laid with which the pre-stressing rod is in engagement and against which the support means bear respectively so that the force excerted on the concrete by the pre-stress are distributed over a large area and there is no danger for the concrete to collapse. Advantageously each pre-stressing rod is received by the concrete and coated with a material to which concrete not adheres. As it is of importance that the flange-shaped member extends as accurately as possible horizontally and moreover the support means have to be in engagement without any clearance with both the flange-shaped member and the upper surface of the pedestal, advantageously the support means are formed by wedge shaped members which are disposed between the upper surface of the pedestal and protruding elements fixed to the flange-shaped member. By these wedge shaped members unevenouses in the upper surface of the pedestal, in particular a concrete slab are smoothed out and a support free of any clearance is ensured. The invention is explained in more detail by referring to the exemplary embodiment shown in cross-section in the drawing. As shown in the drawing an upstanding element for instance a chimney is secured by welding at 2 to a. flange-shaped member 3. To the flange-shaped member 3, adjacent its end edges, the protruding elements 4 and 5 respectively are fixed which elements rest freely on wedge shaped elements 6 and 7 respectively which at their turn rest freely on a washer 8 which is embedded in the slab of concrete 9 forming the pedestal. At the lower side of the concrete slab 9 a washer 10 is received by the concrete with which the pre-stressing rods 11 and 11' are in engagement through their heads 12 and 12' respectively, which rods 11 and 11' extend through the concrete slab 9 and the flange-shaped member 3. By turning the nuts 13, 13' which engage the upper side of the flange-shaped member 3, the pre-stressing rods 11 and 11' are pre-stressed so that the reaction forces are developed at the support means 4, 6 and 5, 7. Since the pre-stressing rods 11 and 11' are in engagement with the flange-shaped member 3 at a point disposed off the center between the support means 4, 6 and 5, 7 and closer to the upstanding element 1, the reaction forces at the support means 4, 6 will be superior to the other reaction forces. When a tensile stress occurs in the upstanding element 1 then this force will lead exclusively to a decrease of the reaction force at the support means 4, 6, said reaction force being so large by a correct choice of the pre-stressing force in the pre-stressing rods 11, 11', .that said reaction force will never disappear completely resulting in that the pre-stressed rods 11, 11' will never be exposed to varying loads and that no bending moments will be developed in the flange-shaped member 3. Around the pre-stressed rods 11 and 11' is provided a hose 14, 14' of a material to which concrete not adheres so that the rods 11, 11' are in sliding engagement with the concrete. The entire space between the outer edge of the flange-shaped member 3 and concrete slab 9 may be filled with a mortar which does not shrink in hardening. OMPI

Claims: CLA IMS 1. A device for securing an upstanding elongated element such as a column, pole or chimney at its lower end to the horizontally extending upper surface of a pedestal, comprising a flange-shaped means fastened to the pedestal and extending substantially in parallel relation with the upper surface of the pedestal, to which flange-shaped means, near its one terminal edge the lower end of the element is secured, characterized in that said flange-shaped means disposed in spaced apart relation with the upper surface of the pedestal, rests freely adjacent its terminal edges on the upper surface of the pedestal through at least one pair of support members which are spaced apart in radial direction and that means are provided which are in engagement with said pedestal for excerting at least one pre-stressing force on said flange-shaped member so that said member is pressed against the pedestal through the support means. 2. Device according to claim 1, characterized in that said means for excerting a pre-stressing force are formed by at least one pre-stressed vertical extending rod which is in engagement at the one side with the flange-shaped means at a point disposed between the support means and at the other side with the pedestal. . 3. Device according to claim 2, characterized in that the point where the pre-stressed rod is in engagement with the flange-shaped means is disposed off-centre between the support means and closer to the support means adjacent to which the upstanding element is secured to the flange-shaped member. 4. Device according to claims 2 or 3, characterized in that each pre-stressed rod extends slidably through the pedestal and the flange-shaped member and each pre-stressed rod is in engagement with the lower surface of the pedestal and with the upper surface of the flange-shaped member. 5. Device according to claim 4 in which said pedestal is formed by a slab of concrete characterized in that in the upper- and lower surface of said slab of concrete a washer is laid with which the pre-stressing rod is in engagement and against which the support means bear respectively . 6. Device according to claim 5, characterized in that the pre-stressed rod is received by the concrete and is coated with a material to which concrete not adheres. 7. Device according to claims 1-6, characterized in that said support means are formed by wedge-shaped members ' which are disposed between the upper surface of the pedestal and protruding elements fixed to the flange-shaped member .

Inventors: BAKVIS HENDRIKUS ANTONIUS, BAKVIS, HENDRIKUS, ANTONIUS
Applicants: BAKVIS BEHEER BV, BAKVIS BEHEER B.V.
Application year: 1984
Main classification: E04H12
IPC codes: E02D27