Super-span variable cross-section prestressing force is just being put the square pyramid space grid and preparation method thereof of finding time
Technical field
The present invention relates to a kind of steel grid roof structure, (120m ≦ L ≦ 180m) variable cross-section prestressing force is just being put the square pyramid space grid and preparation method thereof of finding time to particularly a kind of super-span, belongs to the technical field of construction steel structure.
Background technology
Plate steel mesh frame from nineteen sixty-five by external introduction more than 40 year so far because its space three-dimensional is stressed, factory makes, the on-the-spot installation, operation is simple, steel using amount is few, in single storey industry workshop and public building roof system, is widely used, and reaches tens million of square metres.But wherein span is at (18m~60m) account for more than 90%; Nearly 13 kinds of rack composition forms; No matter which kind of form; They have a common feature is that its clathrum that winds up is parallel in twos (equal altitudes) with lower edge clathrum plane, and the structure of its roof drainage gradient and composition are behind the upright short column of the node that winds up, to be connected to form drainage grade with purlin.When drainage grade required i=7%, during span L=30m, the highest short column reached 1.05m; When span L=60m, the short column height is 2.1m; When span L=155m, short column is up to 5.45m, and it accounts for the total height more than 40%.It is neither stressed with the member co-operation integral body that flat plate framed structure is formed for these members, on the contrary owing to gradient structure reason makes rack because the roof pitch requirement increases a large amount of imposed loads.
Traditional plate steel lattice structure has 13 kinds more than, the ratio of square planar and long limit and minor face less than 1.5 roof system plane in, square pyramid space grid rigidity is best; Between span 18m~60m, use the most extensive, when span is commonly called as super-span, the particularly span roof system at the square or rectangle plane of 120m~180m during greater than 60m; Standard practice is to adopt three layers, pyramid is made up of at rack height centre pyramid two quadrangular pyramids, when span is 155m * 155m; Its structure height reaches 12m, and when roof system drainage grade i=0.07, the post maximum height reaches 5.45m; The total height reaches 17.65m, as the high private residence of six floors, roof structure accounted for architectural complex long-pending 51%; Building periphery cladding increases outside one times more, and room conditioning power must double above, and not only steel using amount is big; Cost is high, and totally unfavorable to " energy-saving and emission-reduction " of building.Prior art is difficult to reach the designing requirement of " safety, reasonable, advanced, economy " to the rigid grid structure of super-span.Develop and a kind ofly not only practice thrift the roof structure height but also guarantee the rigidity of structure, when practicing thrift steel using amount, making the shared cube volume of indoor rigid grid structure is minimum a kind of new spatial network system, is the task of top priority of large-scale super-span building.
Summary of the invention
Technical problem to be solved by this invention is to provide a kind of super-span variable cross-section prestressing force just putting the square pyramid space grid and preparation method thereof of finding time.This rack is applied to super-span, and (the square or rectangle roof system of 120m≤L≤180m) has that steel using amount is low, an advantage such as simple structure, fabrication and installation cost are low, good mechanical performance, is a kind of safe, reasonable, advanced, economic new structure system.
For solving the problems of the technologies described above technical scheme of the present invention: the preparation method that super-span variable cross-section prestressing force is just being put the square pyramid space grid of finding time.This method is along x direction and y direction the Prestressed Space truss to be set at about 1/3 place, both sides of just putting the quadrangular pyramid variable cross-section double layer grid of finding time; On the Prestressed Space truss, prestressed cable is set; And the cable wire supporting steel frame is set in the wind up steel ball upper end of support node at two ends of every Pin Prestressed Space truss; Upper outside at frame column is provided with triatic stay, leans on frame column one side gusset place that the earth anchor cable wire is set at triatic stay; Fixed pulley has a down dip to the span mediad around cable wire supporting steel frame top with an end of prestressed cable; The cable wire that is passed in this Pin Prestressed Space truss lower-chord panel point turns to bracing frame, and the other end is walked around the bottom that is fixed on frame column behind the fixed pulley of triatic stay end; After setting up prestressing force, just putting find time quadrangular pyramid variable cross-section double layer grid and frame column, prestressed cable and self-balancing structural entity of earth anchor cable wire formation.
Super-span variable cross-section prestressing force is just being put the square pyramid space grid of finding time.Its formation comprises just puts the quadrangular pyramid variable cross-section double layer grid of finding time, and is provided with the Prestressed Space truss at said about 1/3 place, both sides of just putting the quadrangular pyramid variable cross-section double layer grid of finding time along x direction and y direction, and the two supports of Prestressed Space truss is on frame column; On the Prestressed Space truss, prestressed cable is arranged, be provided with cable wire in the crosspoint of x direction and y direction Prestressed Space truss lower edge and turn to bracing frame; The two ends of winding up at every Pin Prestressed Space truss are provided with support node, are provided with the cable wire supporting steel frame in the steel ball of support node upper end, are provided with triatic stay in the upper outside of frame column; Fixed pulley has a down dip to the span mediad one end of prestressed cable around cable wire supporting steel frame top, and the cable wire that is fixed on this Pin Prestressed Space truss turns on the bracing frame, and the other end is walked around the bottom that is fixed on frame column behind the fixed pulley of triatic stay end.
Above-mentioned super-span variable cross-section prestressing force is just being put in the square pyramid space grid of finding time, and leans on frame column one side gusset place to be provided with the earth anchor cable wire at described triatic stay, and the other end of this earth anchor cable wire is anchored on the ground.
Aforesaid super-span variable cross-section prestressing force is just being put in the square pyramid space grid of finding time, and described earth anchor cable wire and ground are 60 ° of angles.
Aforesaid super-span variable cross-section prestressing force is just being put in the square pyramid space grid of finding time, and the prestressing apparatus of positive and negative screw thread is housed on described triatic stay and earth anchor cable wire.
Aforesaid super-span variable cross-section prestressing force is just being put in the square pyramid space grid of finding time, two upper chord downwarpings of said Prestressed Space truss, and a lower chord is horizontal straight-bar, two upper chords are connected up and down through four diagonal web members with a lower chord.
Beneficial effect of the present invention: compared with prior art; It is a kind of novel roof structure form that super-span variable cross-section prestressing force of the present invention is just being put the square pyramid space grid of finding time; Be applied to the super-span (roof system of 120m≤L≤180m) of square or rectangle; Compare with existing plate steel mesh frame; Have that steel using amount is low, advantages such as simple structure, fabrication and installation cost are low, good mechanical performance, the superior structural form that to be that super large is striden a kind of in the plate steel lattice structure " safety, rationally, advanced, economy ".It can make whole building building structure (roof system and frame column) overall operation, when improving the rigidity of structure and globality, reaches the reduction steel using amount, practices thrift the purpose of construction costs.The present invention is square pyramid space grid because the employing bilayer is found time; The relative triple layer grid of its node and rod member quantity reduces more than 40%; The maximum height of structure can descend more than 40%; And the present invention adopts the tensile strength prestressed cable higher 7~8 times than common steel tube tensile strength to set up prestressing force and compensates, and forms whole steel grid roof, frame column and wire rope structure self equilibrium systems; Thereby significantly reduce the structural steel amount, satisfying a kind of super-span prestressed steel grid new structural system of formation under the rigidity of structure and the strength condition.
Description of drawings
Fig. 1 is a plane structure arrangement diagram of the present invention;
Fig. 2 be the present invention at x, y is to the grid plane of arrangement figure that establishes Prestressed Space truss zone;
Fig. 3 is the side elevational view of Prestressed Space truss of the present invention;
The A-A sectional view of Fig. 3 of Fig. 4;
Fig. 5 is the axonometric drawing of cable wire upper support steelframe and triatic stay and prestressing apparatus;
Fig. 6 is prestressed cable turns to the bracing frame place at cable wire a axonometric drawing.
Below in conjunction with the accompanying drawing and the specific embodiment the present invention is further described.
The specific embodiment
Embodiment 1.Like Fig. 1, shown in 2, comprise and just put the quadrangular pyramid variable cross-section double layer grid 1 of finding time, can know each direction (X from Fig. 1; The Y direction) 16 Pin variable cross-section space truss quadratures form; And 15 * 15=225 the grid of having found time, the area of promptly finding time reaches 225 * 25=5625 ㎡, accounts for 25% of total roof system area.It is tangible that material usage descends.It is about 40% to know that from Fig. 3 total height of structure has also descended than the three layer flat plate rack of routine, because structure is found time and structure height reduces, its steel using amount descends, but the also corresponding decline of its rigidity, with the instructions for use of not satisfying structure.Be head it off; The present invention adopts roofing cable-stayed prestressing method to make roof structure and supporting frame trestle co-operation; Under the prestressing force effect, form " structure self equilibrium systems "; Its concrete structure is along x direction and y direction two Pin Prestressed Space truss 2 to be set respectively at about 1/3 place, both sides of just putting the quadrangular pyramid variable cross-section double layer grid 1 of finding time, and the two supports of Prestressed Space truss 2 is on frame column 3; Two upper chord 11 downwarpings of Prestressed Space truss 2, a lower chord 12 is horizontal straight-bar, two upper chords 11 are connected up and down through four diagonal web members 13 with a lower chord 12.Prestressed cable 4 is arranged on Prestressed Space truss 2, be provided with cable wire in the crosspoint of x direction and y direction Prestressed Space truss 2 lower edges and turn to bracing frame 5; The two ends of winding up at every Pin Prestressed Space truss 2 are provided with support node 6, are provided with cable wire supporting steel frame 7 in the steel ball of support node 6 upper end, are provided with triatic stay 8 in the upper outside of frame column 3; One end of prestressed cable 4 has a down dip to the span mediad around cable wire supporting steel frame 7 top fixed pulleys; And the cable wire that is fixed on this Pin Prestressed Space truss 2 turns on the bracing frame 5, and the other end is walked around the bottom that is fixed on frame column 3 behind the fixed pulley of triatic stay 8 ends.Triatic stay 8 leans on frame column 3 one side gusset places to be provided with the earth anchor cable wire 9 that is 60 ° of angles with ground, and the other end of this earth anchor cable wire 9 is anchored on the ground.The prestressing apparatus 10 of positive and negative screw thread is housed on triatic stay 8 and earth anchor cable wire 9.
Be example with the square roof structure of 155m * 155m, as shown in Figure 1, at every limit (X; Y) about 1/3 place's arrangement prestress space truss 2; As shown in Figure 3, be provided with support node 6 at each Prestressed Space truss 2 two ends, be provided with cable wire supporting steel frame 7 in the steel ball upper end of support node 6; One end of prestressed cable 4 has a down dip to the span mediad around cable wire supporting steel frame 7 top fixed pulleys; And the cable wire that is passed in this Pin Prestressed Space truss 2 turns to bracing frame 5 horizontal, and two prestressed cables of directions X 4 all turn at this with Y direction prestressed cable 4, forms steering angle; The other end of prestressed cable 4 is walked around the bottom that is fixed on frame column 3 behind the fixed pulley of triatic stay 8 ends.Cable wire turns to bracing frame 5 that four cable wire steering nodes are all arranged.Prestressing force is set up in prestressed cable 4 stretch-draw; Cable wire turn to produce respectively on the bracing frame 5 two by lower-chord panel point upwards effect and with load action opposite effect power; Whole network is provided with four cable wires altogether and turns to bracing frame 5; Then in the construction pre-stress stage, whole super-span network produces and load action opposite effect power.Because this active force is just in time opposite with the node effect of winding up, from rigidity of structure analysis, whole steel lattice structure middle position is equivalent to be provided with four elastomeric bearing points; Each elastomeric bearing point upwards produces active force, and these four by the lower-chord panel point active force (shaping structures attitude) that makes progress, and it makes each rod member of whole network produce the internal force opposite with load action again; (load attitude) upper chord pressurized when being load action; Lower chord is drawn, and its internal force is on the contrary during the prestress forming attitude, then structure normal " user mode " and distortion equal " becoming form " and " load attitude " sum with internal force; I.e. " structure use attitude "=" structure formation attitude "+" structural load attitude "; Because reasonably prestressing force cloth rope mode makes the structure that original rigidity is not enough and internal force is excessive, change into when satisfying rigidity of structure requirement; Reduce structural internal force and distribute, reach the target that reduces the structural steel amount, practices thrift construction costs.Among Fig. 3 and Fig. 4, prestressed cable 4 is walked around the bottom that behind the triatic stay 8 end fixed pulleys that frame column 3 upper outside are provided with, is fixed on frame column 3 after cable wire supporting steel frame 7 outward inclining again again.The prestressing apparatus 10 of the positive and negative screw thread of cast steel manufacturing is set at triatic stay 8 places; The prestressing apparatus 10 that turns clockwise, triatic stay 8 elongations promptly produce stretching forces to prestressed cable 4; After calculating definite stretching force, rotation prestressing apparatus 10 is set up prestressing force.The huge pressure that bears owing to the triatic stay 8 with prestressing apparatus 10 reaches frame column 3 (steel column, concrete filled steel tubular column or reinforced concrete pile); With the effect that makes frame column 3 produce inside sidesway; For this active force of balance; So lean on frame column 3 side gusset places that the earth anchor cable wire 9 that is 60 degree angles with ground is set at triatic stay 8, rotation prestressing apparatus 10 is set up prestressing force, then triatic stay 8 horizontal thrust of passing to frame column 3 is come balance by the earth anchor cable wire 9 that is anchored in ground; Just putting the quadrangular pyramid variable cross-section roof system frame column 3 of finding time this moment, prestressed cable 4, earth anchor cable wire 9 form a self-balancing structural entity.It " reinforcement bar " do not occur as folding prestressed cable wire self equilibrium systems in whole network, but " subtracting the power bar ", thereby reduce the structural steel amount.
Embodiment of the present invention is not limited to the foregoing description, and the various variations of under the prerequisite that does not break away from aim of the present invention, making all belong within protection scope of the present invention.