FR2627792A1 - Stand structure for sports stadium - has reinforced concrete portal structures spaced along length of stand, supporting stepped terraces and suspended roof stanchions - Google Patents

Abstract

The structure has reinforced concrete terraces (1a,b) for spectator accommodation, with a roof structure formed above them. The terraces are supported by reinforced concrete portal structures (3a,b; 4) spaced at intervals along their length and with their cross-beams inclined at approx. 45 deg. Each portal structure supports a metal mast (5) extending upwardly with a slight inclination, and secured by a rigid stay (7). The mast supports a metal beam (10), with a second rigid stay (11), on which the roof structure is formed by metal cross-beams (9) and panels (8). ADVANTAGE - Simple, rapid modular construction.

Description

 Grandstands in covered stands and construction processes.

DESCRIPTION
The present invention relates to covered grandstands and methods of constructing them.

 The technical sector of the invention is that of the construction of civil engineering works.

 The sports or playgrounds are surrounded by grandstands on which the spectators take their places and which are generally protected by a roof.

 A problem to be solved is to design covered stands which can be built quickly because the work must generally be carried out within a relatively short time, for example between two successive seasons for grounds on which seasonal sports are practiced.

 Another problem is to design covered stands, the cost of which is lower than that of the covered stands known to date.

 These problems are solved by means of stands in steps in which the steps are placed on reinforced concrete porticos which are regularly spaced and which comprise a beam inclined at about 450, the upper face of which is cut out in steps and in that each portico supports an inclined metal mast which is pressed against the upper end of each of said beams which extends on either side of this end, the lower end of which is connected to said portal frame by a rigid tie rod which mast supports a metal beam , one end of which is fixed to said mast and which is hooked to a rigid metal tie rod which is fixed to the upper end of said mast, which beam constitutes a crossbowman of a metal frame which supports a roof made of self-supporting metal trays.

A method according to the invention for building grandstands in covered steps comprises the following operations
- regularly spaced gantries are placed in place, each comprising an inclined beam, the upper face of which is cut into steps, which beam is placed on two posts and ends at the quarry and above the rear post;
- prefabricated stands are placed between two gantries;
- Then set up with a crane, and fixed at the upper end of each of said inclined beams, a metal mast which extends on either side of the end of the inclined beam;
- Connecting the lower end of said mast to said inclined beam by a rigid tie;
- A metal beam which extends above said steps is fixed substantially at mid-height of each of said masts;
- Said beam is connected to the upper end of said mast by a second tie;
- And one poses between said beams purlins supporting a roof in metal trays.

 To build the gantries, the pairs of posts of each gantry are cast in place, then a formwork in the form of a metal box is placed on each pair of posts in which said inclined beam is poured and which is capable of supporting the weight of the concrete and of the reinforcement thereof without being supported.

 The invention results in new stands in covered stands.

 The structure of the stands according to the invention makes it possible to easily set up the cantilever frame which supports the protective roof of the stands. The operations of placing the metal masts and the beams hanging cantilevered therefrom to serve as crossbowmen require very little personnel and can be carried out very quickly.

 The construction of the bleachers and in particular of the porticos is facilitated by the fact that the inclined beams of each portico, which support the prefabricated bleachers, are cast in metal boxes in two parts, which require no shoring and which facilitate the installation of the prefabricated reinforcements and plates carrying anchor rods intended to be embedded in the concrete to be used for fixing the metal masts on the reinforced concrete structure.

 The installation of metal masts is facilitated by the fact that each mast has a console which is supported by a ball joint on the top of an inclined beam. The ball joint is located substantially vertical to the center of gravity of the mast, so that once the ball is placed on its support plate, the mast is almost in equilibrium and it is easy to rotate it slightly around the ball joint to place the lateral fixing rods and the lower tie rod. The support ball joint serves only to transmit the vertical forces while the overturning torque around this ball joint due to the overhang of the roof and the wind thrust is balanced mainly by the lower tie rod which works in traction.

 The following description refers to the appended drawings which represent, without any limiting character, an embodiment of a covered platform according to the invention.

 Figure 1 is an overall elevational view of a covered grandstand according to the invention.

 Figure 2 is a vertical section showing the first step in the construction process.

 Figure 3 is a section on III-III of the upper end of each post.

 Figure 4 is a vertical half-section on a larger scale of the upper end of a post equipped with a formwork support member.

 Figures 5 and 6 are a vertical half-section and a front view of a second embodiment of a formwork support.

 Figure 7 is a perspective view of a second step in the construction process.

 Figure 8 is a partial vertical section showing the anchor rods used for fixing a mast on the upper end of a beam.

 Figure 9 is a partial vertical section of the attachment of the lower tie to a gantry.

 Figure 10 is a cross section of a beam formwork.

 Figure 1 is a vertical section of a covered grandstand according to the invention which is placed for example around a sports or playing field and which includes covered bleachers 1, on which spectators take place.

 A grandstand according to the invention is a large work that can contain several tens of thousands of people.

 The objective of the invention is to provide large capacity grandstands which can be built very quickly and at a relatively low cost.

 A platform according to the invention comprises a lower level la and an upper level lb constructed of reinforced concrete.

 The upper level is made up of prefabricated reinforced concrete beams 2, which have a square section, each constituting a step and a step.

 These prefabricated beams are placed on reinforced concrete porticoes which are regularly spaced around the sports field, for example at the rate of a portico every seven meters.

 The tiers lb of the upper level are placed on gantries comprising two posts 3a, 3b and a beam 4 inclined downwards towards the stadium. The tilt angle is around 450.

 The upper face of the beams 4 is cut into steps on which the ends of the prefabricated beams 2 are placed, which extend between two successive gantries.

 Each beam 4 extends above the rear post 3d of each gantry and it supports a metal mast 5 which extends above and below the beam 4.

 The mast 5 comprises, on its internal face, a console part 6 which bears on the top of the upper end of the beam 4.

 The mast 5 is slightly inclined towards the inside while rising and its center of gravity is slightly inside the point of support of the console 6 on the beam, so that under the effect of its only weight, the mast 5 tends to tip inwards by pivoting around the support point of the console 6.

 The lower end of the mast 5 is connected to the gantry 4 by a rigid tie rod which opposes the overturning of the mast towards the inside or even possibly towards the outside under the effect of a push of the wind.

 The masts 5 support a light cover 8 in self-supporting trays which extends in overhang and which covers the steps 1a and 1b.

 The cover tanks are supported by purlins 9 which extend between two beams 10 slightly inclined towards the rear which form the rafters of a metal frame.

 Each mast 5 supports a beam 10 placed in a console a bit like the way a crane mast supports the boom of the crane.

 The outer end of the beam 10 is pressed against the mast 5 at a height sufficient for spectators to be able to stand on the upper tier. Each beam 10 is connected to the mast by a rigid tie rod 11, which is hooked to the upper end of the mast 5 and to a point on the beam 10 set back from the inner end of the beam.

 The tie rod 11 transfers the weight of the roof to the mast 5. Each beam 10 comprises, beyond the point of attachment of the tie rod 11, a console portion whose length is compatible with the mechanical strength of the beam 10.

 Figure 2 shows the first step in the construction of a covered grandstand according to Figure 1.

 We first made the foundations 1? then the first level 1a which includes a floor on technical space 13, a floor 14 carried by posts 3a, 3b, a beam 15 inclined at approximately 45, the upper face of which is cut into steps and a piece of floor 16 carried by the rear posts and an external wall 7.

 The works for this first phase are carried out by pouring reinforced concrete into conventional formwork.

 The posts 3a, 3b are intended to support a heavy load and they have a large section. They rise above the floor 14 at different heights, the internal post 3b being shorter.

 During the casting of the posts, a reservation member is inserted in their upper part making it possible to obtain, after formwork removal, a transverse hole 18 which is shown in axial section in FIG. 3. This hole 18 has a cylindrical central part placed between two frustoconical ends.

 The holes 18 are located at a determined height above the ground. They are intended to receive a support and centering member of a formwork for casting the inclined beam 4 placed on the two posts.

 Figure 4 is a vertical half-section of a post 3a passing through the axis of a cylindroconical hole 18. We see in this figure a support member 19 which has a conical boss 20 which is engaged in one end of the hole cylindroconical 18. Two identical support members are thus engaged in the two ends of each cylindroconical hole 18 and the two members are connected by a threaded rod 21 which passes through the post and on which two nuts 22 are screwed. Each support member 19 comprises a recessed housing 23 which is open upwards and which has inclined walls. This housing receives wedge-shaped parts 24 which form part of a self-supporting metal formwork into which the inclined beam 4 is poured.

 Figure 5 is a vertical half-section similar to that of Figure 4 showing an alternative embodiment.

 This figure shows a support member 19 provided with a conical boss 20 which is engaged in one end of the cylindrical-conical hole 18 passing through a post 3a and which is fixed by a threaded rod 21 and by two nuts 22.

 FIG. 6 is a front view of FIG. 5.

 In the embodiment according to Figures 5 and 6, the formwork support member comprises a hollow part 25 which is engaged on the part 19 on which it can slide vertically. A screw 26, which is screwed into the part 19, makes it possible to move the part 25 in height and to adjust the level thereof. The part 25 comprises, at its upper part, a housing 23 with inclined walls in which the wedge-shaped part 24 engages which is part of a formwork.

 Figure 7 shows, very schematically, the establishment of a first self-supporting half-formwork on the two posts 3a, 3b. The formwork 27 into which the inclined beam 4 of each gantry is cast in place comprises two self-supporting half-forms 27a, 27b made of sheet steel.

 The first of these half-forms 27a has an inclined bottom 28, a vertical side wall 29 and two end walls 30 and 31.

 The bottom 28 has two recesses 32a and 32b in which the respective ends of the posts 3a and 3b engage.

Each recess is bordered on three sides by sheets which frame the top of the post.

 The central sheets which are in the extension of the side wall 29 each carry a wedge-shaped part 24 which comes to bear in the housing 23 shown in FIG. 4 or in FIGS. 5 and 6.

 FIG. 7 represents the half-formwork 27a suspended from the hook 33 of a crane which makes it possible to place it on the two posts 3a and 3b.

 Once the half-formwork 27a is in place, a prefabricated frame made of weldable steel is placed in it. The bars are welded together to form a non-deformable cage.

 Once the reinforcement has been put in place, plates 50a are fixed on the half-formwork carrying threaded rods intended to be anchored in the concrete. Two vertical anchor rods 34 are thus fixed on a horizontal plate 35 which is part of the half-formwork 27a, two or four horizontal anchor rods 36 on the upper end 29 of the half-formwork 27a and two anchor rods 37 on the bottom 28 of the half-form 27a.

 The vertical anchor rods 34 serve to fix the support beam 4 to the concrete beam 4. The horizontal anchor rods 36 serve to fix the inclined mast 5 against the upper end of the concrete beam 4. The anchor rods 37 serve to fix the tie rod 7 to the beam 4.

 Figure 8 is a partial vertical section, on a larger scale, showing the connection of the metal mast 5 and the support console 6 with the upper end of the concrete beam 4 via the anchor rods 36 and 34 embedded in the concrete of the beam. We see in this figure that each anchor comprises a plate 38a, 38b which has been fixed on the internal face of the half-formwork 27a and which is embedded in the concrete. This plate carries on its internal face threaded sleeves 39 which are also embedded in the concrete, in which the rods 34, 36 are screwed which serve as anchors and whose threaded ends protrude outside the beam.

 FIG. 9 likewise shows the anchor rods 37 which are screwed into threaded sleeves 40 welded onto a plate 41 which has been fixed to the internal face of the bottom 28 of the half-formwork 27a.

 After formwork stripping, a yoke 42 is engaged on the threaded ends of the rods 37 in which the end of the tie rod 7 is then engaged.

 Once the anchor rods are put in place on the half formwork 27a, the formwork 27 is completed with a second half formwork 27b.

 Figure 10 is a cross section of the formwork on which we see the first half-formwork 27a having a bottom 28 and a vertical wall 29 and the second half-formwork 27b having a vertical wall 43 and a stepped upper part 44. The wall vertical 43 is extended downwards by two plates 45 which complete the perimeter of the upper part of the posts 3a and 3b and which carry wedge-shaped parts 24 which are positioned in the housings 23 fixed to the posts.

 The metal formwork 27 comprises lower and upper rods 46, which are external to the formwork and which cooperate with nuts 46a to hold the two half-forms assembled. Once assembled, the two half-forms form a box which rests solely on the four support pieces 23 fixed to the two posts 3a and 3b and which has sufficient inertia to support the weight of the concrete of the beam 4 which represents approximately 12 m3 without needing to be propped, which saves time and reduces costs.

 Once the formwork is in place, the concrete is poured into it through pouring holes located at the top.

 After the concrete has hardened, it is stripped. First remove the half-formwork 27b, then lower the half-formwork 27a slightly to detach it from the concrete by acting on the screws 26. Then place between each pair of beams 4 prefabricated elements in the form of a square 2, which constitute the steps.

 The metal masts 5 are then put in place. Each mast is brought suspended from the hook of a crane. The console 6 is brought above the upper end of a beam 4. The console 6 has on its underside a semi-ball joint 6a visible in FIG. 8, which comes to bear in a housing carried by the plate 38b. The threaded rods are engaged in holes in the mast and the bolts are tightened on the threaded rods. Then, an operator grasps the tie rod 7 which is attached to the lower end of the mast. He engages it in the yoke 42 and he sets up a spindle through the tie rod and the yoke to secure them.

 The ball 6a which is located substantially above the center of gravity of the mast transmits to the beam 4 the weight of the latter.

 The anchor rods 36 and 37 balance the mast overturning torque due to the weight of the roof and the action of the wind.

 Once a mast is in place, a crossbowman 10 is brought in, which is suspended from the hook of a crane and which carries its upper link 11.

 An operator fixes one end of the crossbowman to the mast with bolts. Then? the tie rod 11 is pivoted and an operator will hang it on the upper end of the mast. Then, between the masts, inclined cross-shaped braces are put in place, then purlins 9 are placed between the rafters 10 and steel trays forming the covering 8 are placed on these purlins.

Claims (8)

 1. Covered stands of the type comprising reinforced concrete steps (la, lb), on which spectators take their places and a roof (8) placed above said steps, characterized in that said steps are placed on concrete porticos reinforced, (3a, 3b, 4), which are regularly spaced and which include a beam (4) inclined at approximately 450, the upper face of which is cut into steps and in that each gantry supports a metal mast (5) inclined which is pressed against the upper end of each of said beams (4), which extends on either side of this end, the lower end of which is connected to said portal frame by a rigid tie rod (7), which mast supports a metal beam (10), one end of which is fixed to said mast (5) and which is hooked to a rigid metal tie rod (11) which is fixed to the upper end of said mast (5), which beam constitutes a crossbowman of a metal frame (9) which supports a roof (8) in metal tubs freestanding.  2. Method for constructing covered stands of the type comprising reinforced concrete steps (la, lb) protected by a roof (8), characterized in that  - regularly spaced gantries are placed in place, each comprising an inclined beam (4), the upper face of which is cut into steps, which beam (4) is placed on two posts (3a, 3b) and extends to the rear and above the rear post (3a) -;  - Prefabricated steps (2) are placed between two gantries;  - Then put in place, with a crane, and is fixed at the upper end of each of said inclined beams a metal mast which extends on either side of the end of the inclined beam;  - Connecting the lower end of said mast (5) to said inclined beam (4) by a rigid tie (7);  - A metal beam (10) which extends above said steps is fixed substantially at mid-height of each of said mast;  - Said beam (10) is connected to the upper end of said mast (5) by a second tie rod (11);  - And is posed between said beams purlins (9) supporting a roof (8) in metal trays.  3. Method according to claim 2, characterized in that the pairs of posts (3a, 3b) of each gantry are poured in place, then a formwork (27) in the form of a metal box is placed on each pair of posts. said inclined beam (4) is poured and which is capable of supporting the weight of the concrete and the reinforcement thereof without being supported.  4. Method according to claim 3, characterized in that at the upper end of each post (3a, 3b) a cylindroconical hole (18) which crosses said post is fixed and at each end of each of said holes is fixed, a support member (19) of said metal formwork (27) which has a conical boss (20) which penetrates into said hole (18) and the two support members (19) are connected by a threaded rod (21) which passes through said post and on which two nuts (22) are screwed.  5. Method according to claim 5, characterized in that each of said support members (19) is equipped with a hollow part (25) which can slide vertically on said support member and the height of said hollow parts (25) is adjusted. by means of screws (26) which are screwed into said support members.  6. Method according to claims 3 to 5, characterized in that one first sets up between two posts (3a, 3b) unpremierdemi-coffrage (27a, 27b) having an inclined bottom (28), a side wall vertical (29) and two end walls (30, 31), place a prefabricated reinforcement in this half-formwork and then put in place, between the two posts (3a, 3b) a second half-formwork (27b) which has a vertical side wall (43) and a stepped top (44) and the two half-forms are assembled together by threaded rods (46) cooperating with nuts (46a) to form a box.  7. Method according to claim 6, characterized in that one fixes on the internal wall of the first half-formwork plates (38a, 38b, 41) carrying threaded sleeves (39, 40) in which are screwed rods anchor (34, 36, 37), which are embedded in the concrete and which serve for fixing said metal mast (5) and said lower tie (7) to said beams.  8. Method according to claim 7, characterized in that each metal mast (5) comprises a console (6) which is provided with a semi-ball joint (6a) which is supported on a plate (38b) embedded in the end upper of each inclined beam (4), which half-ball joint is located substantially vertical to the center of gravity of the metallic mast (5).