CN110886423B

CN110886423B - BIM technology-based steel structure tension beam roof construction method

Info

Publication number: CN110886423B
Application number: CN201911103003.7A
Authority: CN
Inventors: 李世勇; 温江; 陈松; 夏瑞; 杨琴
Original assignee: Chengdu Rong Zheng Software Co ltd
Current assignee: Chengdu Rong Zheng Software Co ltd
Priority date: 2019-11-12
Filing date: 2019-11-12
Publication date: 2022-03-22
Anticipated expiration: 2039-11-12
Also published as: CN110886423A

Abstract

The invention relates to a construction method of a steel structure tension beam roof based on a BIM (building information modeling) technology, which belongs to the technical field of building construction. The invention applies the BIM technology, and adopts BIM three-dimensional dynamic simulation in advance to cyclically stretch all the beam string beams in three batches and two stages, thereby reducing the construction period to the maximum extent on the premise of ensuring the minimum influence on the adjacent group of beam string beams when different groups of beam string beams are subjected to inhaul cable stretching construction. The jacks which need to be put in altogether are 1/3 the number of the beam string, so that the equipment investment of the jack 2/3 is reduced, the economic benefit is good, the construction quality is better controlled, the operation is mature, and the safety of the construction process is high.

Description

BIM technology-based steel structure tension beam roof construction method

Technical Field

The invention relates to the technical field of building construction, in particular to a construction method of a steel structure tension beam roof based on a BIM (building information modeling) technology.

Background

The beam string is a novel hybridization roof system different from the traditional structure. The beam string structure is a mixed structure system formed by a rigid member upper string, a flexible inhaul cable and a vertical support rod connected in the middle, and the structure of the beam string structure is a novel self-balancing system, is a large-span prestressed space structure system and is also a successful creation in the development of the mixed structure system. The beam string structure has the advantages of simple system, definite stress, various structural forms, full play of the advantages of rigid and flexible materials, simple and convenient manufacture, transportation and construction, and good application prospect.

In the construction of the roof with the spoke beam string structure, the defects of large investment of tensioning equipment and large tensioning cost generally exist.

The BIM (building Information modeling) technology is proposed first in 2002 by Autodesk company, is widely recognized in the world at present, can help to realize the integration of building Information, and all kinds of Information are always integrated in a three-dimensional model Information database from the design, construction and operation of a building to the end of the whole life cycle of the building, and personnel of design teams, construction units, facility operation departments, owners and the like can perform cooperative work based on the BIM, thereby effectively improving the working efficiency, saving resources, reducing the cost and realizing sustainable development.

Disclosure of Invention

The invention aims to provide a construction method of a steel structure tension beam roof based on a BIM technology, which can reduce the construction period to the maximum extent and reduce the equipment investment of a jack on the premise of ensuring the minimum influence on adjacent groups of tension beam strings when different groups of tension beam strings are subjected to tension cable construction.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a BIM technology is applied in the construction process of a spoke type beam string structure roof, a virtual spoke type beam string structure roof is established in advance through the BIM, an upper chord beam and a lower chord beam are supported through vertical support rods to form a beam string structure, and a central rigid ring is arranged to connect the beam string structures to form the roof;

the lower chord beams are set as prestressed inhaul cables, simulation analysis of the whole process of virtual inhaul cable stretching construction is carried out by applying a BIM technology, the tensioned chord beam inhaul cables are circularly stretched in three groups and two stages, and the cable force and key point displacement of each lower chord beam in the stretching process are dynamically tracked.

And in the first stage, the critical point that the three groups of beam string beams are separated from the jig frame is taken as a finishing mark, and then the three groups of beam string beams are subjected to second-stage tensioning again.

Preferably, the first group of tensioning is divided into two stages which are 5 stages: 0- > 25% -50% -72% of initial tension is taken as a first stage, and the first stage takes a critical point of the string beam breaking away from the jig frame as a finishing mark; in the second stage of tensioning, firstly, tensioning a group of guys with initial tensioning force of 72% -90%; and then, rotating to a second group to perform the same operation until all the three groups are tensioned to 90% of the initial tensioning force, and finally performing the cycle operation again until all the inhaul cables are tensioned to 105% of the initial tensioning force.

Preferably, 30 truss-string box-shaped beams are radially arranged on the roof.

Further, after the upper chord beam and the vertical stay bar are hoisted, installing a stay cable; the inhaul cable installation steps are as follows;

step 1, the stay cable is unfolded along the axial direction of the beam string, the lower cable head is arranged below the central rigid ring, the upper cable head is arranged below the peripheral ring beam, and a bolt ball is arranged on the ground according to the mark on the surface of the cable body; a crane is used for hoisting the lower rope head and is connected with the central rigid ring;

step 2, lifting the middle of the inhaul cable by utilizing a plurality of hoists on the upper chord beam, shortening the linear distance of the cable end, simultaneously using the hoists as temporary fixing to hoist the inhaul cable, installing a traction device on the cable head, and drawing the cable head to penetrate through the cable hole of the peripheral ring beam under the assistance of the traction device, the crane and the hoists;

and 3, fixing the bolt ball on the inhaul cable with the lower end of the vertical support rod from inside to outside in sequence.

Furthermore, the upper chord beams and the vertical support rods are assembled on the ground, and auxiliary hoisting rigging is adopted to hoist the upper chord beams; the auxiliary sling comprises a carrying pole, two steel wire ropes connected with the carrying pole, and at least two slings; the lower ends of the two steel wire ropes are connected with the carrying pole, the upper ends of the two steel wire ropes can be connected with the same lifting ring, the carrying pole is connected with the upper end of the sling, and the lower end of the sling is connected with the upper chord beam.

Furthermore, deformation of each beam string is monitored in the tensioning process, a monitoring point is arranged on the upper surface of the upper beam string above each vertical support rod, and a monitoring point is arranged in the center of the top of the central rigid ring; and a monitoring point is arranged at the joint of the upper chord beam and the peripheral ring beam.

Compared with the prior art, the invention has the following beneficial effects:

the invention applies the BIM technology, and adopts BIM three-dimensional dynamic simulation in advance to cyclically stretch all the beam string beams in three batches and two stages, thereby reducing the construction period to the maximum extent on the premise of ensuring the minimum influence on the adjacent group of beam string beams when different groups of beam string beams are subjected to inhaul cable stretching construction. The jacks which need to be put in altogether are 1/3 the number of the beam string, so that the equipment investment of the jack 2/3 is reduced, the economic benefit is good, the construction quality is better controlled, the operation is mature, and the safety of the whole construction process is high.

Drawings

FIG. 1 is a three-dimensional view of a radial beam string;

FIG. 2 is a front view of the column shoe structure;

FIG. 3 is a cross-sectional view taken at A in FIG. 2;

FIG. 4 is a sectional point schematic view of an outer wind-resistant column;

FIG. 5 is a schematic diagram of the hoisting of the wedge-shaped section of the outer wind-resistant column;

FIG. 6 is a schematic view of the hoisting of the curved section of the outer wind-resistant column;

FIG. 7 is a schematic view of a beam string installation;

FIG. 8 is a schematic structural view of a central rigid ring;

FIG. 9 is a schematic illustration of the hoisting of the top chord beam;

FIG. 10 is a schematic view of the shoulder pole;

FIG. 11 is a schematic view of the lower cable head mounting of the lower chord beam;

FIG. 12 is a schematic view of a lanyard;

FIG. 13 is a schematic view of the cable installation completed;

FIG. 14 is a schematic structural view of a cable;

FIG. 15 is a schematic structural view of a beam string supporting jig;

FIG. 16 is a beam contour plot;

FIG. 17 is a schematic view of a first stage stretch completion;

FIG. 18 is a schematic position diagram of a single beam monitoring point;

FIG. 19 is a graph of vertical mid-span displacement and horizontal sliding support displacement during tensioning as a function of tensioning force.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings.

The invention discloses a construction method of a steel structure tension beam roof based on a BIM technology, which applies the BIM technology in the construction process of a spoke type tension beam roof structure and predicts the completion time of a project through BIM three-dimensional dynamic simulation of the whole construction process.

A virtual spoke type beam structure roof is built in advance through BIM, as shown in figure 1, 30 beam string box-shaped beams are radially arranged on the roof, each beam string beam 5 comprises an upper beam string and a lower beam string, the upper beam string and the lower beam string are supported through vertical support rods to form a beam string structure, a central rigid ring 3 is arranged to connect the beam strings 5 to form the roof, and the roof structure is supported on a soil-mixed wall 1. Mix the 1 outside of earth wall and be equipped with anti-wind post 11, anti-wind post 11 top is connected with peripheral gird 2, and anti-wind post 11 bottom is connected with the basis, and anti-wind post 11 middle part is connected with earth wall 1.

The cross section of the main rod piece of the roof is box type and H type. The span of the roof is 100m, the rise of the center is 9.5m, the upper chord of the beam string is a box-shaped section, the lower chord is a prestressed inhaul cable, and the steel consumption is 2100T.

The stay cable adopts OVM series PES5-199 stay cables in the construction stage, and the area of the steel wire bundle is 3905mm²The diameter of the steel wire bundle is 77mm, the theoretical weight of the steel wire bundle is 30.7kg/m, the breaking load is 6525kN, and the diameter of the double-layer inhaul cable is 93 mm. The inhaul cable adopts high-strength steel wire bundles, the tensile strength is more than or equal to 1670MPa, the relaxation rate is less than or equal to 2.5 percent, the yield strength is more than or equal to 1410MPa, and the elastic modulus E = (1.95-2.1). times.10⁵MPa。

The anchorage device adopts a cold casting anchor series matched with the inhaul cable, and the number of the anchorage device is OVMLZM 5-199. The end parts of the vertical support rods of the beam string are connected by pin bolts, the pin bolts are made of 40Cr steel, the diameter of each pin hole is 0.5mm larger than the diameter of each bolt, and the pin bolts are manufactured by finish machining.

The stay cable provides elastic support for the rigid upper chord beam through the rigid vertical stay bar, the span of the beam is reduced, the bending moment peak value of the rigid beam is reduced, and then the effects of increasing rigidity and reducing deflection are achieved. The quantity of vertical vaulting pole sets up as required, and the effect of vertical vaulting is for providing elastic support for the upper chord roof beam. Generally, as the number of vertical struts increases, the bending moment and the shearing force of the upper chord beam gradually decrease. But the improvement of the stress of the member is not obvious after the number of the vertical supporting rods is increased to a certain number.

The construction process mainly comprises the following steps: installing an outer ring wind-resistant column → installing a central rigid ring → hoisting an upper chord beam and a stay cable → tensioning the stay cable → dismantling a temporary support. The steps are as follows.

And step 1, mounting the outer ring wind-resistant column.

The column base structure is shown in fig. 2 and 3 and comprises embedded steel bars 113, foundation beams 12, reinforced concrete short columns 13, embedded plates 14, bottom plates 15 and shoe beams 17. The embedded plate 14 is embedded in the reinforced concrete short column 13 and is connected with the reinforced concrete short column 13 through a plurality of embedded steel bars 113 in an anchoring manner, and the embedded steel bars 113 are anchored in the reinforced concrete short column 13 and the foundation beam 12. The quantity and the size of embedded steel bar 113 set up as required, and embedded steel bar 113 has 6 in this embodiment, and the diameter of embedded steel bar 113 is 32 mm.

The bottom plate 15 is fixedly connected with the buried plate 14 through a transition plate 19, the transition plate 19 is arranged between the buried plate 14 and the bottom plate 15, the transition plate 19 is welded with the buried plate 14, and the bottom plate 15 is connected with the transition plate 19 through a plurality of high-strength bolts 20. The number of the high-strength bolts 20 is set according to the requirement, 8 high-strength bolts 20 are provided in the embodiment, and 4 high-strength bolts 20 are provided on both sides of the shoe beam 17.

The bottom plate 15 and the transition plate 19 are provided with preformed holes matched with the embedded steel bars 113, and the upper ends of the embedded steel bars 113 penetrate out of the preformed holes. The bottom of the shoe beam 17 is welded and fixed with the bottom plate 15. The quantity and the size of embedded steel bar 113 set up as required, and embedded steel bar 113 has 6 in this embodiment, and the diameter of embedded steel bar 113 is 32 mm. Two sides of the shoe beam 17 are respectively provided with 3 embedded steel bars 113. The embedded steel bars 113 can be replaced by high-strength screws. The shoe beam 17 is inclined, the stiffening ribs 16 are arranged on two sides of the shoe beam 17 in an abutting mode, and the stiffening ribs 16 are fixedly welded with the shoe beam 17. The bottom plate 15, the stiffening ribs 16, the transition plate 19, the extending parts of the embedded steel bars 113 and the bottom of the shoe beam 17 are all buried in the outer wrapping concrete 18.

The shoe beam 17 is welded with the bottom plate 15 together, and then is welded, reinforced and fixed through the stiffening ribs 16 on two sides, the bottom plate 15 is connected and fixed with the embedded foundation through the high-strength bolts, the pressure of the column can be transmitted to the bottom plate 15, and the pressure is diffused by the bottom plate 15 and transmitted to the foundation. The shoe beam 17 and the stiffening rib 16 are arranged on the bottom plate 15, and the bottom plate 15 is divided into a plurality of small cells; the shoe beams 17 and the stiffening ribs 16 on the bottom plate 15 are equivalent to boundary supports of the cell lattices, so that the supporting condition of the bottom plate 15 is changed, and the maximum bending moment of the bottom plate is reduced under the action of foundation reaction force; meanwhile, the boot beam 17 and the stiffening ribs 16 enable the axial force of the column to be diffused towards two directions, and the reinforced concrete short column 13 is arranged below the bottom plate 15, so that the column base can be effectively prevented from sinking, and the reliability of a structural system is improved.

The construction method comprises the following steps: (1) and (3) pre-embedding and installing an outer ring wind-resistant column anchor bolt: installing a positioning bolt, integrally fixing angle steel → binding bottom plate steel bars → leveling rectangular steel plates → pouring bottom plate concrete to a position 50mm away from the bottom surface of a column foot plate → installing column feet → adjusting column feet elevation → fixing anchor bolts and nuts → welding a transition plate → pouring C50 micro-expansion concrete to the bottom plate surface.

(2) Outer lane anti-wind post crab-bolt locating rack: each anchor bolt needs to be fixed at the opposite position by an upper layer of angle steel and a lower layer of angle steel, and the angle steel and the anchor bolt need to be welded into a vertical state.

(3) The outer ring wind-resistant column is embedded and column base is installed: utilize bracing and cushion control crab-bolt elevation, the bracing will be with the whole fixed firm of crab-bolt. After the anchor bolt is fixed, the anchor bolt and the surrounding reinforcing steel bars are firmly welded by the reinforcing steel bars. Before concrete is poured, the anchor bolts are retested, and the position and elevation deviation is immediately corrected. When concrete is poured, the concrete is prevented from falling to impact the anchor bolt to cause deviation, and the embedded part is well protected. And (4) carrying out pressure-bearing grouting after the adjustment of the secondary grouting support base plate is finished, wherein the secondary grouting material is C50 micro-expansion concrete. And welding the transition plate and the embedded plate, and finishing the construction of the whole column base.

(4) Outer ring wind-resistant column installation

The outer wind-resistant column of the roof with the spoke type beam string structure is long in length and heavy, and the weight is about 6.2 t; and it includes a curved section 111 and a wedge-shaped section 112. If integral hoisting is adopted, the length is long, so that the swing amplitude is large in the hoisting process, and the hoisting safety is affected; the weight is heavy, so that the hoisting difficulty is high. Therefore, as shown in fig. 4, 5 and 6, the outer-ring wind-resistant column is installed by adopting a sectional hoisting construction method, so that the sectional hoisting is light in weight and convenient to operate; the hoisting length is reduced, the swing amplitude in the hoisting process is also reduced, the swing amplitude is convenient to control, and the hoisting process is safer.

And 2, mounting the central rigid ring. And completing the construction of the central rigid ring and the peripheral beam of the roof before hoisting the beam string. As shown in fig. 7, the central rigid ring 3 is supported by the central rigid ring support jig frame 4, and a sliding support is arranged between the central rigid ring 3 and the central rigid ring support jig frame 4, so that the jig frame can be effectively prevented from being inclined in the tensioning process, and the construction safety is facilitated.

The central rigid ring 3 is formed by welding square steel pipes with unequal cross sections, a total of 14 latticed columns are arranged as main stress supports of the central rigid ring, and the central rigid ring is assembled in a dispersed hoisting mode by adopting an 80T crane. As shown in fig. 8, the central rigid ring 3 includes an upper ring beam 31 and a lower ring beam 32, the diameter of the upper ring beam 31 is greater than that of the lower ring beam 32, holes are reserved on the upper ring beam 31, the lower ring beam 32 and the peripheral ring beam 2 as tensioning nodes, and prestressed anchors are installed at the tensioning nodes.

The installation of the central rigid ring 3 adopts a construction method of arranging lattice constructional columns and high-altitude bulk loading of scaffolds. Central rigid ring 3 rigid ring assembly process: the lattice column is arranged, in order to facilitate operation, a scaffold is erected to a position about 1m away from the bottom of the inner ring, an inner ring main ring steel beam is assembled → an inner ring side vertical face is assembled, the scaffold is assembled along the side vertical face, the scaffold ascends step by step → the inner ring side vertical face is assembled, the scaffold is erected to a position about 1m away from the bottom face of the outer ring, preparation is made for construction of the top outer ring of the neutral ring → assembly of the top inner ring main ring steel beam → assembly of the top outer ring main ring steel beam → assembly of the whole central rigid ring.

And step 3, hoisting the upper chord beam.

And (4) assembling the upper chord beams and the vertical support rods on the ground, wherein the number of the upper chord beams and the vertical support rods is 30, and hoisting the upper chord beams and the vertical support rods in place by a crane meeting the construction performance requirement.

In order to reduce the downward deflection deformation during the hoisting process of the beam string, the invention uses an auxiliary hoist rigging to hoist the upper beam string 51, as shown in fig. 9, the auxiliary hoist rigging comprises a carrying pole 9, two steel wire ropes 101 connected with the carrying pole 9, and at least two slings 103.

The lower ends of the two steel wire ropes 101 are connected with the carrying pole 9, and the upper ends of the two steel wire ropes 101 can be connected with the same hoisting ring so as to be connected with a crane conveniently. The upper ends of the suspension ropes 103 are connected with the carrying poles 9, and the lower ends of the suspension ropes 103 are connected with the upper chord beams.

As shown in fig. 10, two lifting eyes 10 are welded to the top surface of the carrying pole 9, at least two lifting eyes 10 are welded to the bottom surface of the carrying pole 9, and the number of lifting eyes 10 on the bottom surface of the carrying pole 9 is equal to the number of slings 103. The lifting lug 10 has a lifting hole 102. The steel wire rope 101 is connected with the lifting lug 10 on the top surface; the sling 103 is connected to the lifting eye 10 on the bottom surface. The ear plate is made of Q235B material, the thickness t =14mm, and the single ear plate is forced by about 70 KN. In order to reduce the diameter of the rope, the steel wire rope 101 is in a rope sleeve form, a 6 x 37 steel wire rope is selected, the diameter is phi 26, and the breaking tension is 426.5 KN.

Two reinforcing inclined struts 7 are added during hoisting. The vertical stay 53 at the center of gravity of the beam string 5 is found. Two reinforcing diagonal braces 7 are respectively installed at both sides of the vertical brace 53. The lower end of the reinforced inclined strut 7 is connected with the lower end of the vertical strut 53 at the center of gravity, the upper end of the reinforced inclined strut 7 is connected with the upper end of the vertical strut 53 at the side, and the joint is anchored by a bolt.

The position of the upper chord 51 connected with the vertical stay 53 is used as a hanging point 511, and the sling 103 is wound by one circle at the hanging point 511 on the upper chord 51 to realize the connection with the upper chord 51. When two slings 103 are provided, the hanging points 511 connected with the slings 103 are the hanging points 511 at both sides of the vertical stay 53 at the center of gravity. In order to facilitate the adjustment of the installation position of the upper chord beam 51 after hoisting, the carrying pole 9 is connected with a chain block 8. The shoulder pole is used as an auxiliary lifting appliance, so that the stress points of the upper chord beam can be increased, the upper chord beam is uniformly stressed, and the upper chord beam can be prevented from being deformed in a downwarping mode in the lifting process; but also can improve the stability in the hoisting process.

As shown in fig. 7, one end of the upper chord beam 51 is rigidly connected to the central rigid ring 3, the other end is reliably connected to the sliding support on the peripheral ring beam of the roof, the middle part of the upper chord beam 51 is supported by the bracing jig 6, the number of the bracing jigs 6 is set according to the requirement, and the bracing beam 5 is supported by two bracing jigs 6. The central rigid ring supporting jig frame 4 and the beam string supporting jig frame 6 are fixed on a foundation. And hoisting the upper chord beams in place clockwise or anticlockwise according to the axis, synchronously installing ring beams and annular supports between the beam string members, and gradually installing to complete all the ring beams and the annular supports.

Other small-sized rod pieces comprise secondary rod pieces between inner ring beam string beams, connecting beams between outer ring wind-resistant columns and the like, and the part of the rod pieces are light in weight and can be installed by adopting an on-site crane.

And 4, installing a stay cable.

After the hoisting of the upper chord beam and the vertical stay bar is finished, the inhaul cable is installed. Therefore, when the inhaul cable is installed, a construction platform is erected at the support of the peripheral ring beam 2 of the roof. As shown in fig. 14, a multi-segment sleeve 54 is sleeved outside the cable 52, and the installation of the bolt ball 55 is completed, the cable 52 passes through the bolt ball 55, and a plurality of bolt balls 55 are installed on the cable 52. The sleeve 54 is provided with a plurality of sleeves, so that the original characteristics of the inhaul cable 52 are kept, the tension of the inhaul cable is not influenced, and the inhaul cable 52 can be effectively protected.

As shown in fig. 15, a cable escape space 61 is reserved in the beam string supporting jig 6. The beam string supporting jig 6 is composed of a plurality of first supporting frames 62 and two second supporting frames 63, and the plurality of first supporting frames 62 are arranged up and down. The two second support frames 63 are arranged between the two first support frames 62 at intervals, and the interval between the two second support frames 63 forms a cable escape space 61. The string beam supporting jig frame 6 is convenient to assemble and disassemble, and after the guy cable is tensioned, the jig frame does not need to be cut off, and the string beam supporting jig frame only needs to be disassembled from top to bottom one by one, so that the string beam supporting jig frame can be repeatedly used.

The inhaul cable installation method specifically comprises the following steps:

(1) dragline hoisting

And the crane unloads the guy cable from the transportation equipment and unfolds along the axial direction of the beam string. The lower cable head is arranged below the central rigid ring 3, the upper cable head is arranged below the peripheral ring beam 2, and the bolt ball is arranged on the ground according to the mark on the surface of the cable body. The lower rope head is hoisted by a crane and is connected with the central rigid ring 3;

(2) reeving rope

The plurality of hoists 8 on the upper chord beam 51 are used for lifting the middle of the inhaul cable 52, the linear distance of the cable end is shortened, and meanwhile, the hoists 8 are used for temporarily fixing and hoisting the inhaul cable 52. And a traction device is arranged on the upper cable head, and the upper cable head is pulled to pass through the cable hole of the peripheral ring beam 2 under the assistance of the traction device, a crane and a hoist 8.

(3) Positioning installation of cable clip

The length of the stay cable passing through the upper cable head is adjusted to be as long as possible, and the bolt ball 55 and the lower end of the vertical support rod 53 are fixed from inside to outside in sequence. And after the cable is installed in place, pre-tightening the cable for tensioning.

And 5, tensioning the stay cable.

After the central rigid ring 3, the beam main body (the upper beam 51, the vertical stay 53, and the stay 52) and the support are mounted, the tension work is performed. When the tension is performed, each beam string can affect other beam string, especially the adjacent beam string is greatly affected. Therefore, the invention utilizes BIM technology to carry out simulation analysis of the whole process of virtual inhaul cable tensioning construction, dynamically tracks the cable force and the displacement of key points in the tensioning process, compares the inhaul cable analysis data and selects a tensioning scheme.

The principle of beam string tension control is generally divided into two parts of force and shape, wherein the force mainly is cable force, and the shape mainly is the rise and span of the beam.

In the invention, one end of a single guy cable is tensioned, the tensioning end is arranged at the peripheral ring beam, the guy cable is disconnected at the central rigid ring, and the possibility of uneven guy force of guy cables of the same guy beam is easy to occur. Therefore, synchronous staged tensioning is adopted, the cable force value is taken as a control index in each stage of tensioning, and the cable force value and the displacement value of the monitoring point are taken as control indexes in the last stage of tensioning, so that the cable force of each cable section is ensured to be uniform.

The beam string guy cable is circularly tensioned in three groups and two stages, and each group comprises 10. As shown in fig. 16, the 1 st, 4 th, 7 th, 10 th, 13 th, 15 th, 16 th, 19 th, 22 th, 25 th and 28 th axes are set as one group, the 2 nd, 5 th, 8 th, 11 th, 14 th, 17 th, 20 th, 23 th, 26 th and 29 th axes are set as two groups, and the 3 rd, 6 th, 9 th, 12 th, 15 th, 18 th, 21 th, 24 th, 27 th and 30 th axes are set as three groups.

In the first stage, the critical point that the three groups of beam string beams are separated from the jig frame is taken as a finishing mark, and then the three groups of beam string beams are tensioned again in the second stage. Specifically, the first group of tensioning time is divided into two stages which are 5 stages: 0- > 25% -50% -72% of initial tension is the first stage, and the first stage takes the critical point of the string beam breaking away from the jig frame as a completion mark, as shown in fig. 17; in the second stage of tensioning, firstly, tensioning a group of guys with initial tensioning force of 72% -90%; and then, rotating to a second group to perform the same operation until all the three groups are tensioned to 90% of the initial tensioning force, and finally performing the cycle operation again until all the inhaul cables are tensioned to 105% of the initial tensioning force.

And in the prestress construction process, a calibrated jack is adopted to monitor cable force, and a total station is adopted to monitor displacement monitoring. The cable force control adopts a jack which is calibrated in a matched mode, and the jack which is tensioned on site is calibrated in a qualified laboratory in a matched mode with an oil pressure gauge. A main plane control network point for lofting of the total station is included in an elevation control network, the adjustment of joint measurement is unified, the basic network and the encryption network of the elevation control network are kept consistent in precision, and the retest precision is the same as the network building precision. Forced centering and fixing observation pier seats are arranged on control points for lofting and observation; and other control points should be forced to center and fix the marker post as much as possible so as to facilitate accurate alignment. And the total station is adopted to perform three-dimensional lofting by the control point, so that a very high precision effect is achieved.

Purlines are arranged between the beam strings and connected with the beam strings through high-strength bolts. The purline is installed after being tensioned, and a quick wrench with a falling prevention device is used in the installation process.

And tracking the whole construction process according to the construction scheme, and analyzing the change data of the key response of the structure along with the construction process. The construction process analysis was performed according to the following 11 steps:

(1) erecting a support frame, and installing structural components in place;

(2) tensioning a first group of inhaul cables, and performing 3-stage loading on the tensioned inhaul cables, wherein the tensioning values are 25%, 50% and 72% of the initial tensioning force respectively;

(3) tensioning a second group of inhaul cables, and performing 3-stage loading on the tensioned inhaul cables, wherein the tensioning values are respectively 25%, 50% and 72% of the initial tensioning force;

(4) tensioning a third group of inhaul cables, and performing 3-stage loading on the tensioned inhaul cables, wherein the tensioning values are 25%, 50% and 72% of the initial tensioning force respectively;

(5) tensioning a first group of cables, wherein the tensioning value is 90% of the initial tensioning force;

(6) tensioning a second group of cables, wherein the tensioning value is 90% of the initial tensioning force;

(7) tensioning a third group of cables, wherein the tensioning value is 90% of the initial tensioning force;

(8) tensioning a first group of cables, wherein the tensioning value is 105% of the initial tensioning force;

(9) tensioning a second group of cables, wherein the tensioning value is 105% of the initial tensioning force;

(10) stretching a third group of guys, wherein the stretching value is 105 percent of the initial stretching force, and forming the structure;

(11) installing roofing system and permanent road, and forming roof.

Table 1: tension string beam cable force value meter

The beam string deformation monitoring position is shown in fig. 18: the horizontal sliding of the 7-axis support and the vertical displacement of a plurality of points on the beam are realized, the number of the points on a single beam is 15, and a monitoring point is arranged on the upper surface of the upper beam 51 above each vertical strut 53. A monitoring point is arranged at the center of the top of the central rigid ring 3; the joint of the upper chord beam 51 and the peripheral ring beam 2 is provided with a monitoring point, and the monitoring point is provided with a prism 14. And monitoring deformation of each beam string.

The monitoring points are arranged at the beam cross joint positions of the upper chord beam and are also supporting points of the support, the stress of the position is most concentrated, the displacement of the upper chord beam changes along with the tension in the center of the tensioning process of the lower chord beam, and the joints are the positions with the most obvious changes; furthermore, the adjustment of the displacement by the abutment is also performed at this node, i.e. by adjusting the position of the monitoring point to the position of the monolithic beam at design. The displacement of the beam string monitoring points is shown in tables 2 and 3.

Table 2: vertical displacement value meter for beam string monitoring point

Table 3: horizontal displacement value meter for beam string

In the process of tensioning a single beam string, the mid-span vertical displacement and the horizontal displacement of the sliding support of the structure are changed along with the gradual increase of the tensioning force.

The method analyzes the tensioning process of a typical beam string, and draws the curve of the vertical displacement of the midspan and the horizontal displacement of the sliding support along with the variation of the tensioning force, as shown in fig. 19. Therefore, the relation curve of displacement-tension force is nonlinear because the beam string gradually falls off the frame in the tensioning process. When the tension of the guy cable (single cable) reaches about 940kN, the central rigid ring is separated from the supporting jig frame, and then the midspan vertical displacement is rapidly increased along with the increase of the tension. In view of that when the tension force is larger, the midspan displacement of the central rigid ring is sensitive to the tension force, so that the midspan displacement is monitored in the tensioning process, and the final tension force is properly adjusted according to the deformation condition of the beam in the later stage of tensioning, namely, the deformation control is mainly used in the later stage of tensioning, and the cable force control is assisted.

The pay-off and positioning measurement method comprises the following steps:

(1) designing a net distribution scheme: and taking an in-field central point and a control line as a survey station and taking an out-of-field point as a direction point to lay a measurement control net for steel structure engineering construction. 12 control points are arranged in the gymnasium.

(2) And (3) laying an elevation measurement control network: in the early stage of construction, the plane measurement control point is also used as an elevation control point. The leveling operation uses the high altitude difference method, the middle wire micrometer reading method carries on the reciprocating measurement, the leveling rod uses the indium steel rod, and controls the number of the measuring stations as the even number between the control points, in order to eliminate the influence of the zero point difference, the observation sequence is 'back-front-back'.

And (4) closing the leveling route to determine the elevation of each elevation point by using a leveling method II and the like and leveling precision requirements III and the like.

(3) Measuring an anchor part: and checking the concrete column measurement data and the anchoring piece measurement data submitted in the previous procedure according to the established plane control network and the elevation control network. The measurement data includes three parts of column center line positioning and elevation measurement drawing, completed center line and elevation measurement data and settlement and displacement observation data. The allowable error of the column top embedded part handed over in the previous procedure is (+ 0 ≥ 3 mm), the deviation of the central line of the column top embedded part is +/-5 mm, and the integral levelness is less than 1 mm.

(4) And measuring the verticality of the truss: the method of combining the plumb bob and the plumb bob is adopted for inspection, and the measurement method is shown in the following page.

(5) And (3) settlement observation: and laying settlement observation points, and carrying out regular settlement observation along with construction until the work is checked and accepted, a user unit is handed over, and the construction method and the precision requirement are detailed in deformation monitoring operation.

(6) And (3) deformation monitoring: the detection of the plane horizontal displacement adopts a direction line method or a polar coordinate method, the settlement observation is carried out according to the burying and observation requirements of the settlement observation mark, and the regular observation is carried out. The selection of the point location of the settlement point must be firm and reliable, and the continuous use after the production is ensured. The embedding of the point location is preferably about +0.500 meter, which is convenient for observation.

After the structure is hoisted, formal settlement observation points need to be welded at the designed position, the observation period is generally one month, and the observation period can be properly adjusted according to the progress of field engineering. If the settlement is abnormal or the deformation is large, the observation period should be shortened, and the first-hand data should be grasped to determine the cause of settlement change.

And selecting one or two permanent level points as elevation starting points outside the area far away from the construction affected area. The sight distance is not more than 40 meters, the height is not less than 0.5 meter, and the length of the leveling route is not more than 1.6 kilometers in the observation process.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore intended that all such changes and modifications as fall within the true spirit and scope of the invention be considered as within the following claims.

Claims

1. A steel structure tension beam roof construction method based on a BIM technology is characterized in that: the BIM technology is applied in the construction process of the spoke type beam string structure roof, a virtual spoke type beam string structure roof is established in advance through the BIM, the upper and lower beam strings are supported by the vertical support rods to form a beam string structure, and a central rigid ring is arranged to connect the beam strings to form the roof;

the lower chord beams are set as prestressed inhaul cables, simulation analysis of the whole process of virtual inhaul cable stretching construction is carried out by utilizing a BIM technology, the tensioned chord beam inhaul cables are circularly stretched in three groups and two stages, and the cable force and key point displacement of each lower chord beam in the stretching process are dynamically tracked;

the building of the roof with the spoke type beam string structure comprises the following steps:

step 1, mounting an outer ring wind-resistant column;

step 2, constructing the central rigid ring and the peripheral beam of the roof;

the central rigid ring is supported by a central rigid ring supporting jig frame, and a sliding support is arranged between the central rigid ring and the central rigid ring supporting jig frame;

step 3, hoisting the upper chord beam;

assembling the upper chord beams and the vertical support rods on the ground, and hoisting the upper chord beams by adopting auxiliary hoisting rigging; the auxiliary sling comprises a carrying pole, two steel wire ropes connected with the carrying pole, and at least two slings; the lower ends of the two steel wire ropes are connected with the carrying pole, the upper ends of the steel wire ropes are connected with the lifting ring, the upper end of the sling is connected with the carrying pole, and the lower end of the sling is connected with the upper chord beam; the carrying pole is connected with a chain block;

increase two enhancement sprags during hoist and mount, specifically do: finding the vertical brace rod at the gravity center of the beam string, respectively installing two reinforcing diagonal braces at two sides of the vertical brace rod, connecting the lower ends of the reinforcing diagonal braces with the lower end of the vertical brace rod at the gravity center, connecting the upper ends of the reinforcing diagonal braces with the upper ends of the lateral vertical brace rods, and anchoring the connecting nodes by bolts;

step 4, after the upper chord beam and the vertical stay bar are hoisted, installing a stay cable, wherein the stay cable is installed in the following steps;

step 4.1, the stay cable is unfolded along the axial direction of the beam string, the lower cable head is arranged below the central rigid ring, the upper cable head is arranged below the peripheral ring beam, and a bolt ball is arranged on the ground according to the mark on the surface of the cable body; hoisting the lower cable head by using a crane to connect the lower cable head with the central rigid ring;

step 4.2, lifting the middle of the stay cable by utilizing a plurality of hoists on the upper chord beam, shortening the linear distance of the cable end, simultaneously using the hoists as temporary fixing to hoist the stay cable, installing a traction device on the upper cable head, and drawing the upper cable head to penetrate through the cable hole of the peripheral ring beam under the assistance of the traction device, the crane and the hoists;

and 4.3, fixing the bolt ball on the inhaul cable and the lower end of the vertical support rod from inside to outside in sequence.

2. The BIM technology-based steel structure tension beam roof construction method according to claim 1, wherein: in the first stage, the critical point that the three groups of beam string beams are separated from the jig frame is taken as a finishing mark, and then the three groups of beam string beams are tensioned again in the second stage.

3. The BIM technology-based steel structure tension beam roof construction method according to claim 2, wherein: the first group of tension is divided into two stages which are 5 stages: 0- > 25% -50% -72% of initial tension is taken as a first stage, and the first stage takes a critical point of the string beam breaking away from the jig frame as a finishing mark; in the second stage of tensioning, firstly, tensioning a group of guys with initial tensioning force of 72% -90%; and then, rotating to a second group to perform the same operation until all the three groups are tensioned to 90% of the initial tensioning force, and finally performing the cycle operation again until all the inhaul cables are tensioned to 105% of the initial tensioning force.

4. The BIM technology-based steel structure tension beam roof construction method according to claim 1, wherein: and 30 truss string box-shaped beams are radially arranged on the roof.

5. The BIM technology-based steel structure tension beam roof construction method according to claim 1, 2 or 3, characterized in that: deformation of each beam string is monitored in the tensioning process, a monitoring point is arranged on the upper surface of the upper beam string above each vertical support rod, and a monitoring point is arranged in the center of the top of the central rigid ring; and a monitoring point is arranged at the joint of the upper chord beam and the peripheral ring beam.