1 scope
This technology is applicable to high steel
grid structure in bulk, overall lifting of ground or aerial sliding method
(upgrade) installation process.
2 construction preparation
2.1 materials
2.1.1 installation of steel grid structure
of steel and materials, high strength bolts, welding electrodes, welding wire,
flux, and so on, should comply with the design requirements and should have a
factory certificate.
2.1.2 installation of steel grid structure
with welding hollow ball, ribbed weld, bolt-ball. Semi-finished small spelling
units, bars, as well as semi-finished products such as rubber, should comply
with the design requirements and the corresponding provisions of the national
standard.
2.2 the main tools:
Welding machines, oxyacetylene cutting
equipment, wheel saws, bar cutting lathes, bar cutting head, steel tape
measure, steel ruler, calipers, theodolite, level instrument, ultrasonic flaw
detector, magnetic particle flaw detector, lifting equipment, lifting
equipment, hammers, hydraulic jacks, chain, wire brush and other tools.
2.3 operating conditions:
2.3.1 install prior to inspection line
check axis grid bearing and elevation. Grid axis, elevation location must
comply with the design requirements and the relevant provisions of the
standards.
2.3.2 Installing the front should check the
column strength of concrete, roof concrete strength must comply with the design
requirements and the State after the provisions of the relevant existing
standards, in order to install.
2.3.3 use of aerial sliding method, should
check the sliding rail pulley, levels of slip slope should comply with the
design requirements.
Section 2.3.4, block installation,
worktable when sliding, check table, sliding devices on the ground, and glide
test.
2.3.5 using whole or partial lifting when
Diego, should check the lifting equipment, lifting speed, lifting cranes, high
closing and adjustment work well test, you must meet the requirements of
construction organization design.
2.3.6 air when in bulk, should set up
all-round scaffolding, and line the fulcrum position and elevation. Bolt the
ball high when in bulk, should be designed to set up temporary stand, and
provisional number of Fulcrum's position, after checking to make sure.
2.3.7 high bulk of temporary support
magistrates or Jack is appropriate, such temporary Fulcrum can gradually adjust
rack height. When the end of the installation when removing temporary supports,
you can drop in synchronization between the fulcrum, subparagraph unloading.
3 operational processes
3.1 bolt ball corners square grid with high
altitude in bulk:
3.1.1 technological process:
Line installation install bottom plane,
inspection line → network → network → install the bottom triangle filled inverted triangle network →
Adjustment and fastening welding → support →
installation roof CAP, acceptance
3.1.2 line, test line and basic checks:
Top 3.1.2.1 checking concrete strength.
Check sample report, qualifying top in the sky line, test line.
3.1.2.2 packages provided top axis
displacement, grid units installed on the grid provided support point location,
dimensions, reinspect, upon re-inspection after check the axis position,
elevation dimensions comply with the design requirements, to start the
installation.
3.1.2.3 temporary location, quantity,
fulcrum of the fulcrum height should be arranged, pivot the lower part should
be properly reinforced, preventing grid point the local force is too large,
rack sink.
3.1.3 install bottom flat grids:
3.1.3.1 a first cross between bearing
installation, on the axis of the top good, center line, good elevation with a
spirit level, errors should be corrected.
3.1.3.2 installed first across-down ball,
Rod, forming vertical plane grid.
3.1.3.3 form a temporary stand, and ensure
the bottom ball of parallelism, such as arching requirement should be found on
the temporary stand base.
3.1.3.4 Setup first across the Web with the
first ball, usually a ball Web of small units in place, with the bottom ball is
screwed into the fixed.
3.1.3.5 installed first across the top
chord, control grid size. Note that is screwed into the depth effects to entire
truss deflections, should control the size.
3.1.3.6 check grids, grid size, check the
grid vertical size and net loss of higher dimensions. If a discrepancy, you can
adjust the temporary position to control the height of the fulcrum of grid
size.
3.1.4 Installing filled inverted triangle
meshes:
3.1.4.1 Web Unit assembled by continuous
installation method.
3.1.4.2 from bearing started to install a
bottom chord, check the thread quality, cleaning up the screw, screw, clean
screwed into, also from the bottom chord of the first cross-also a bottom
chord, composed the first grid penalty into the first section, closed the
bottom chord of the first grid.
3.1.4.3 install inverted triangle cones,
ball three small units (that is, a wound ball, a winding bar fight, two small
abdominal helical rods unit) into the scene. The two diagonal supports on the
bottom ball, tighten the top chord of the top, the top chord of gradually
winding the ball close to the installed, is screwed into.
3.1.4.4 the tilt rod is screwed into the
bottom ball holes, tighten, another slash can temporarily empty.
3.1.4.5 continue to install the bottom ball
and rod (the second grid, down a ball is a ball). A rod is screwed into the
bottom chord of the ball screw holes, one in the forefront installation, with a
tilt rod connection is screwed into the horizontal bottom chord (second)
installed into place, two each with screwed the ball into to form closed the
bottom chord of the second grid.
3.1.4.6 process as described above to
continue installing ball three triangular pyramid, installed vertically between
the two inverted triangle cone winding rod and make it into one. Step by step,
each installed a set of triangular pyramid, installing a vertical top chord,
the top chord of two bolted into the truss chord grid closed also.
3.1.4.7 progressively installed to the
support form a series of vertical triangular grid. Check the vertical size,
check the truss deflections, check the pivot force.
3.1.5 installation factory chords are
triangle meshes:
3.1.5.1 Web after installing the inverted
triangular pyramid grid, the regular triangular pyramid grid installs.
3.1.5.2 installed down the ball and Rod
ball rod form (that is, down ball and the bottom chord), the rod is screwed
into the support holes.
3.1.5.3 install horizontal bottom chord,
ball and bar closed square grid, check the dimensions. Can also take the form a
ball (last quarter sphere and perpendicular two bottom chord grid closed the
Quartet also installed).
3.1.5.4 install side diagonal Web members,
single rod in place, screwed into the rise of the control grid.
3.1.5.5 continue to install the other side
diagonal Web members, screwed into the bottom chord of the ball on both sides
with the first ball to complete a set of regular triangular pyramid grid. Step
by step installation to one side, until the supports so far.
3.1.5.6 each after the completion of a
regular triangular pyramid, then install the check the winding square grid size
error, gradually adjust and tighten bolts. Regular triangular pyramid grid
installation, timely attention to temporary situations of fulcrum.
3.1.6 adjustment and fastening.
3.1.6.1 high bulk installation grid, should
check the network quality measurements at any time. Check the bottom chord size
and diagonal, check the wound size and diagonal, longitudinal length check
grid, horizontal grid Vector length, high. The provisional support can also be
adjusted without having to dismantle.
3.1.6.2 check grid overall deflection can
bottom chord by chord size adjusted to control deflection.
3.1.6.3 network shall at all times during
the installation process checks the sinking of the temporary stand, such as
decline, should be strengthened to prevent sudden falling phenomenon.
3.1.6.4 Web inspection, adjustment, should
back the grid of high-strength bolt fastening.
3.1.6.5 grid after high-strength bolt
fastening, sleeve should be positioned on the small nut lock.
3.1.7 install roof Cap head:
3.1.7.1 weld Cap head screw into the wound
ball.
3.1.7.2 in Hat head elements found on the
slope for the installation of roofing sheets.
3.1.7.3 unused holes in the bolt and bolt
sleeve, plugging the gaps between the bars should be to prevent rainwater
seepage.
3.1.8 support welded and acceptance;
3.1.8.1 check grid size after passing
checks whether the bearing positions on the axis, and the offset dimension.
Grid size when installing cumulative error should be dispersed on both sides to
prevent side bearing in place correctly, the other side bearing too large.
3.1.8.2 check rack elevation, rise, pivot
grid elevation to four to each pivot should be standard size error.
3.1.8.3 check truss deflections.
3.1.8.4 dimensions are qualified, support
weld.
3.1.8.5 support welded should have
instructions. Grid bearings have a spring-type, slip, rubber mats. Support
welded bearing performance should be protected. The intrusion of some
protection against welding spatter, rubber pad when soldering, should prevent
flame grilled wound pads, welding should be water cooled the supports at any
time to prevent baking wound pads.
3.2 welding spherical surface installation
closure method:
3.2.1 the process flow:
Line, test line → install
install install stereo nets → grids → chord grid → grid integral lifting →
Grid height folding → network
acceptance
3.2.2 line, test line:
3.2.2.1 the top line and the test line:
axis and elevation marked, check the cylinder displacement; NET installation
unit and the network support position, size, after reinspection is correct, the
elevation, to be installed.
3.2.2.2 grid installation leveling the
ground setting out, net frame spherical Fulcrum be placed line indicating the
position and the ball.
3.2.2.3 of net frame spherical Fulcrum
brick piers. DUN material can be steel supports, or brick piers plus a bit of
pipe as net rack on bottom ball bearing.
3.2.2.4 each point marked elevation, such
as truss arch request should be reflected at the bearing points, supported by
different height of Arch of steel tube to complete the grid requirements.
A flat installation 3.2.3 steel grid:
3.2.3.1 ball has been and acceptance of
welded ball, by specification, number in the install node, while ball better
direction and location. Generally horizontal center line of circular welding
seam the ball placed in the direction of the equator. Ribbed side in the last
quarter of the top half of the ball.
3.2.3.2 places bar: good bar, arranged
according to the specifications set forth in steel pipes. Placed before the
Member, should check the specifications, size bars and Groove and weld seam
gap, put the rod in between the two balls, adjust the clearance, solid.
3.2.3.3 plane assembled from the Centre lines
of the grid, and gradually to show around, form a closed square grid, control
size, together again around the grid, continued to expand. Note You should
control the cumulative error, generally mesh with negative tolerance is
advisable.
3.2.3.4 flat screen frame welding, welding
to welding technology and frame welding should be well prepared in order to
prevent deformation of plane truss.
3.2.3.5 flat screen frame welding according
to the welding requirements, from center line of steel pipe under the left
20~30mm arc, welding to the right, leaning through welding, welding, uphill
welding, brazing, welding position.
3.2.3.6 tube welded diagonal serrated
weaving technique should be used for welding, preventing bites of meat.
3.2.3.7 welding after weaving to the survey
center line on the tube, move on weld 20~30mm arc.
3.2.3.8 soldering is completed after the
half, again from the right side of the center line of the underside of the pipe
reverse arcs 20~30mm, welded to the left, the same as the above process, to
continue after the top centerline forward, filling the crater, smooth weld lap
in order to guarantee the welding quality.
3.2.4 rack main body Assembly:
Planar grid size, axis offset 3.2.4.1 check
acceptance, check is correct, continue to assemble the main grid.
3.2.4.2 small spelling of a spherical
four-bar units (one ball for the first ball and four-bar truss diagonal Web
members) into the flat above the grid.
3.2.4.3 small spell units in place, should
check the mesh size, rise, as well as small spell unit diagonal angle,
position, angle was the first correction, correction must be qualified after
the installation.
3.2.4.4 installation found is inconsistent
spelling unit bar length, angle, cutting machine for too long poles should be
cut and heavy Groove, re-seated checks.
3.2.4.5 need liner network, should be on
the ball good spot welding liner. Small spelling units do not plane grid spot
and temporarily also works with top chord before welding.
3.2.5 steel truss hip joint Assembly and
welding:
3.2.5.1 in first plane the vertical bars of
the network, check the wound ball vertical position and size are correct.
3.2.5.2 in first plane transverse bars of
the grid, check the first lateral the ball position and size are correct.
3.2.5.3 by stereo small spelling unit
diagonal Web members properly adjusted, so filled the vertical and horizontal
bars and welded ball seats properly. Adjustment method of diagonal Web members
is, to cut a long rod, chain opening angle of tilt rod can also be used, so rod
is seated properly. Ensure correct chord grid size.
3.2.5.4 adjustment of the clearance and the
clearance after passing the Basic, then spot weld the top chord.
3.2.5.5 solid after the winding bar and
spot last quarter and slash the ball seam and connected firmly.
3.2.5.6 checked size, gradually moving
forward. Truss webs and the installation of the truss top chord should be
combined with each other.
3.2.5.7 grid floor after installation,
should install a grid or block size acceptance.
3.2.5.8 grids must be welded to be hoisting
operation is completed, weld appearance quality weld seam ultrasonic inspection
report after passing to lift (lift).
3.2.6 web hoisting (lift):
3.2.6.1 overall hoisting steel grid before
the inspection, weld inspection, acceptance of the upper bearing. After meeting
the design requirements for the acceptance, before lifting.
3.2.6.2 overall hoisting steel grid should
be selected before lifting point lifting rope should be tied to the bottom
point, no hanging on the wound ball joints. If the grid stiffness in the
lifting process is not also means strengthening suspended grid. Reinforcement
was added several temporary reinforcement scaffold steel pipe, but should take
into account this will increase lifting weights, increased load.
3.2.6.3 developed lifting (raise) program,
debug installation (upgrading) devices. For lifting equipment such as hoists
the rod, cable inspection, examination of the hydraulic circuit to ensure
lifting (raise) a smooth, continuous, each hanging point synchronization.
3.2.6.4 load test (promoted): grid should
be tried before the official lifting. Testing process is to hoist up, adjust
the lifting point at the same time gradually from the ground. Try between the
200~300mm off the ground. The point after all, temporarily fixed, force the
observation grid sections. If deformation can be reinforced in time, you should
also carefully check whether the network frontiers of hoisting touching or
hanging debris or temporary scaffolding, as there should be ruled out. Should
also observe the bearing capacity of hoisting equipment, you should try to keep
the lifting point synchronization to prevent tilting.
3.2.6.5 continuous lifting: when checking
out, continuous lifting, on the premise of keeping citizens do not tilt should
be continuously progressive lifting (raise). Fighting for the day in place,
preventing winds.
3.2.6.6 gradually in place: truss lift is
in place, should gradually reduce lift (lift) speed to prevent lifting.
3.2.7 high closure:
3.2.7.1 grid height in place, adjust the
distance between grid and support, and to that end should be installed above
the grid sets used for horizontal adjustment of the chain.
3.2.7.2 check overall elevation grid,
preventing the level of unevenness, such as it is difficult to exclude, from
the side elevation to be put in place, adjust the horizontal chain, high
qualified end in place.
3.2.7.3 height and horizontal distance from
the first qualified at one end, insert the connection, connecting rods can be
amended at any time, heavy Groove, but fixed Rod length is not too big, you
should try to keep the original size. Adjustment is made while tensioning
chain, loosen chain on the other side, distances from the right step by step.
3.2.7.4 should be gradually adjusted side
bar after all the solid, relaxed side chain, continue to fine tune elevation on
the other side of the grid. Can a small amount of lift or down control
elevation. Note at this time adjusting the lifting or descent should be a small
amount of, step by step, not continuous. Adjustments should also be observed
already in place fixed side of the grid to prevent welding.
3.2.7.5 Web side elevation adjustment,
chain tensioning distance, initial checks in place, right after, insert the
stopper, fixing.
3.2.7.6 solid grid bars around the
insertion point. Attention welding rod at this time that there is a slope, the
grid Center is slightly higher than support. Result grid when the effects of
lifting from the Center, once the unloading will drop slightly, to prevent
deformation and should enhance the margin of 3~5mm ahead.
3.2.7.7 solid after the bars closed around
the grid point, check the grids ministries and in order, carried out according
to welding process welding.
3.2.8 Web acceptance:
3.2.8.1 network acceptance is conducted in
two steps, the first step is that grid lifting State of acceptance; the second
is network independent loading, and handling during loading inspection.
3.2.8.2 check the weld appearance quality
of space truss, shall meet the design requirements and standards requirements.
3.2.8.3 four frontier rod (the closing of
welded pipe), in ultrasonic flaw detection of welding 24h reports and repair
records.
3.2.8.4 check grid bearing weld quality.
Lifting equipment unloading 3.2.8.5 steel
grid. Observation of deformation of the grid. Grid lifting parts of unloading
should be slow, synchronized, to prevent local deformation grid.
3.2.8.6 chain to be closed separately
removed and restoration of steel grid structure of natural state.
3.2.8.7 check the grid bearing force; check
the arch truss or arch.
3.2.8.8 check the rack overall dimensions.
4 quality criteria
4.1 project shall comply with the following
requirements:
4.1.1 high bulk installation of grid
structure, accessories and elements of the node, should comply with the design
requirements and the current national provisions relating to standards.
Accessories and deformation of the rod must be corrected.
Inspection method: Visual check and
inspection certificates of quality, factory certificate or test report.
4.1.2 top level Datum axis, columns and
concrete strength, must comply with the design requirements and the current
national provisions relating to standards.
Test method: check the survey records and
reports.
4.2 Basic project shall comply with the
following requirements:
4.2.1 appearance quality of truss nodes and
elements:
Eligibility: clean the surface without
welding scar, mud and sand, dirt.
Good: the surface is clean, no welding
scar, sediment and dirt.
Check amount: according to the number of
nodes check 5%, but should not be less than 5 nodes.
Inspection method: Visual check.
4.2.2 grid structure weight and roof
deflection on completion:
Qualified: measuring deflection of
1.12~1.15 times the average design values.
Excellent: measuring deflection of an
average of 1.12 times times the design value.
Check size: small-span truss structure
measuring down the central spot; medium-span truss structure measuring the
bottom chord of the central point and the bottom chord span four equal points.
Inspection method: with a ruler and level
checks.
4.3 allowable deviation shall meet the
following requirements:
4.3.1 high tolerances for bulk installation
of grid structure project and the test method should meet the requirements of
table 5-23.
Total grid structure assembling method for
the determination of allowable deviation and table 5-23
Tolerance (mm) method
±L/2000
± 30.0
L/3000
30.0
The supporting grid
Adjacent pedestal height difference L/400
15.0
Supports maximum height difference 30.0
with ruler, level check
Multipoint support grid
Adjacent pedestal height difference L1/800
30.0
l2/1000
5.0
Note: 1. L is the vertical length.
2. L1 for the adjacent seat spacing.
3. L2 as the rod length.
4.3.2 approach installation of grid
structure of the allowable deviation and the test method should meet the
requirements of table 5-24.
Check amount: total inspection.
Apart from the high altitude in bulk, and
other methods to install the allowable deviation of grid structure and test
method for table 5-24
Tolerance (mm) test method
L/3000
30.0
L1/400
15.0
Pedestal height
L1/800
30.0 with ruler and level checking
Supports maximum height difference 30.0
Note: 1. L truss spans.
2. L1 for the adjacent seat spacing.
5 finished product protection
5.1 grid once installed, when removing the
shelves should note the synchronization step by step disassembly to prevent
stress concentration, making local distortion grid, or distort the local grid.
5.2 installation of steel grid structure
after the end of time brushing paint. Bolt-net card after the installation, you
should check that the bolt holes on the ball is closed, apply Putty to holes
and paint tube after filling the gaps, and prevent the penetration of moisture,
rust, Rod threaded the ball.
5.3 after the installation of steel grid,
finished product rack protection, not above the grid focus stacking objects.
Such as when there is a need to install roofing panels, purlins, and should
also not overloading the separate pieces.
After installing 5.4 steel grid, such as
with a crane when lifting or roof Purlin, should have happened, no impact grid
grid deformation.
6 quality problems to be noticed
6.1 steel grid during installation, set to
the temporary pivot should be taken seriously. Prior to installation, arranged
for pivots and pivot level, temporary stand to keep the grid even by force, the
rod force, should also pay attention to an interim point basis (scaffolding)
stability, must be taken to prevent Fulcrum sinks.
6.2 temporary supports blocking best to
Jack so that you can gradually adjusted during the installation process. Note
the temporary adjustment of the pivot of a point should not be adjusted, also
taking into account the force evenly around the grid, sometimes local
adjustment will allow individual members, bending deformation.
6.3 temporary stand disassembly caution
protection should be synchronized in group, in descent, decreasing range not
too large, should be step by step section proportional decline in stages, or
with less than 100mm per step step of demolishing the support-point drop.
6.4 welded spherical grid structure of the
installation when welding, should take into account the deformation of welding
contraction, especially lifting rack and bar space truss, installed on the
ground, to control the welding before welding deformation and shrinkage. Steel
mesh welding, welding points (heating surface) plane grid on the upper side,
and very easy to make structural deformation due to unidirectional heat.
General deformation law for grid structure after welding, will gradually free
up around the bearings, if deformation when the springing of the original plan
will be offset. As the original regardless of the arch, made the large
deflection value produced, affects the quality of inspection requirements.
Therefore should be considered in the construction welded spherical grid
structure to a single heat distortion.
6.5 Web after installation should pay
attention to support forces, some bearing allows welded shut, some bearing
should be the free end, some bearing limit and more, so the grid supports the
construction should be carried out in strict accordance with the design
requirements. Bearing plate, limit boards should be required to order, method
of installation.
7 quality records
This standard shall meet the following
quality records:
7.1 bolts, welding-ball, high-strength
bolts of material proof, factory certificate, a variety of carrying tensile
test report.
7.2 the material certificate and retest
report of steel.
7.3 material proof of welding and coating
materials, factory certificate.
7.4 sleeve, Cone and plate sealing material
reports and factory certification, such as steel, material weldability test
report.
7.5 steel pipe with cover plate, cone
composed of Rod bearing test report.
7.6 steel grid activity (or sliding)
bearings should be factory-qualified certificates and test reports.
7.7 Welder certification, should have the
appropriate welding station, the corresponding welding material and other
projects.
7.8 Installing the grid after the overall
size, springing and acceptance data.
7.9 weld inspection and acceptance record.
7.10 weld seam ultrasonic inspection
reports and records.
7.11 coating (including corrosion
protection and fire safety) construction inspection records.
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