AU2021102015A4 - Method for detecting the influence of adjusting distances between web members on the bearing capacity of a parallel chord wooden truss - Google Patents
Method for detecting the influence of adjusting distances between web members on the bearing capacity of a parallel chord wooden truss Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 48
- 238000011068 loading method Methods 0.000 claims abstract description 52
- 238000012360 testing method Methods 0.000 claims abstract description 16
- 239000002023 wood Substances 0.000 claims abstract description 16
- 238000013461 design Methods 0.000 claims abstract description 14
- 238000005452 bending Methods 0.000 claims abstract description 8
- 238000012512 characterization method Methods 0.000 claims abstract description 8
- 230000003068 static effect Effects 0.000 abstract description 6
- 241000771208 Buchanania arborescens Species 0.000 abstract description 5
- 238000010276 construction Methods 0.000 abstract description 5
- 238000003908 quality control method Methods 0.000 abstract description 4
- 239000000463 material Substances 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000005253 cladding Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 230000002028 premature Effects 0.000 description 2
- 244000050510 Cunninghamia lanceolata Species 0.000 description 1
- 241000534018 Larix kaempferi Species 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000005445 natural material Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C3/00—Structural elongated elements designed for load-supporting
- E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
- E04C3/12—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of wood, e.g. with reinforcements, with tensioning members
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04H—BUILDINGS OR LIKE STRUCTURES FOR PARTICULAR PURPOSES; SWIMMING OR SPLASH BATHS OR POOLS; MASTS; FENCING; TENTS OR CANOPIES, IN GENERAL
- E04H12/00—Towers; Masts or poles; Chimney stacks; Water-towers; Methods of erecting such structures
- E04H12/02—Structures made of specified materials
- E04H12/04—Structures made of specified materials of wood
- E04H12/06—Truss-like structures
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
- E04B1/26—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons the supporting parts consisting of wood
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C3/00—Structural elongated elements designed for load-supporting
- E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/0202—Control of the test
- G01N2203/0212—Theories, calculations
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0676—Force, weight, load, energy, speed or acceleration
Abstract
This invention relates to bearing capacity of a parallel chord wooden truss, in particular, to a
method for detecting the influence of adjusting distances between web members on the bearing
capacity of a parallel chord wooden truss. The method includes: S1, applying the Smsolver
mechanics solver model to analyze and calculate a variation range of distances between web
member nodes of a parallel chord wooden truss, axial forces of chords and web members, and a
distribution of truss bending moments, and evaluating possible failure modes and locations to
provide theoretical support for truss form designing and bearing capacity tests; S4, measuring
upper chord internodes, lower chord internodes, the maximum deflection of a lower chord, the
ultimate deflection of the truss, and a axial strain of the truss; and S5, observing failure
characterizations, analyzing failure modes, and obtaining an effective node spacing and
component failure mode in the design of SPF parallel chord wood trusses. The present invention,
by adopting the method disclosed herein, can effectively solve the problem that span control
cannot arrange web members in the construction site, and it adopts a static loading test to
provide a theoretical basis for the quality control and strength control of light wood trusses.
Si, applying the Smsolver mechanics solver model to analyze and calculate a
variation range of distances between web member nodes of a parallel chord wooden
truss, axial forces of chords and web members, and a distribution of truss
bending moments, and evaluating possible failure modes and locations to provide
theoretical support for truss form designing and bearing capacity tests;
S2, using devices including one DH5908 wireless dynamic strain acquisition system, one
laptop, one set of loading beams and brackets, five dial indicators, one DY2200-K1T2
force sensor, fifty-six 20mm gauge length strain gauges;
S3, adopting a hydraulic manual loading method to load the parallel chord wooden
truss synchronously at designated positions, wherein a graded loading system is
used for preloading the parallel chord wooden truss before a formal loading;
T.
S4, measuring upper chord internodes, lower chord internodes, the maximum
deflection of a lower chord, the ultimate deflection of the truss, and a axial
strain of the truss;
T,
S5, observing failure characterizations, anallyzinfailure modes,
and obtaining an effective node spacing and component failure mode in the
design of SPF parallel chord wood trusses.
Fig 1
1/3
Description
Si, applying the Smsolver mechanics solver model to analyze and calculate a variation range of distances between web member nodes of a parallel chord wooden truss, axial forces of chords and web members, and a distribution of truss bending moments, and evaluating possible failure modes and locations to provide theoretical support for truss form designing and bearing capacity tests;
S2, using devices including one DH5908 wireless dynamic strain acquisition system, one laptop, one set of loading beams and brackets, five dial indicators, one DY2200-K1T2 force sensor, fifty-six 20mm gauge length strain gauges;
S3, adopting a hydraulic manual loading method to load the parallel chord wooden truss synchronously at designated positions, wherein a graded loading system is used for preloading the parallel chord wooden truss before a formal loading;
S4, measuring upper chord internodes, lower chord internodes, the maximum deflection of a lower chord, the ultimate deflection of the truss, and a axial strain of the truss;
S5, observing failure characterizations, anallyzinfailure modes, and obtaining an effective node spacing and component failure mode in the design of SPF parallel chord wood trusses.
Fig 1
1/3
This invention relates to bearing capacity of a parallel chord wooden truss, in particular, to a
method for detecting the influence of adjusting distances between web members on the bearing
capacity of a parallel chord wooden truss.
Parallel chord wooden trusses are mainly made of renewable wood, which are
environmentally friendly, and have light weight, high strength, and good seismic resistance.
Parallel chord wooden trusses are made of standard wood as the base material and mostly adopt
frame-type wood components assembled by tooth plate connectors, which mainly include upper
and lower chords, web members, and connectors. Parallel chord wooden trusses can not only
transmit vertical loads, but also resist lateral loads with the help of floor cladding, wall studs, and
wall cladding. Experts have studied the joint bearing capacity and member bearing capacity of
parallel chord wooden trusses. For example, Wang Zi studied the static load-bearing performance
of Japanese larch single-chord light wood trusses, and concluded that the main failure points of
horizontal parallel-chord wooden trusses are trisection points of the trusses and connection
nodes of diagonal webs at both ends, and that for vertical parallel-chord wooden trusses, after
loading twice the designed load, out-of-plane deformation gradually appears and finally results in
large lateral deformation and failures. Wang Zhiqiang conducted a static loading test on
fast-growing Chinese fir parallel string trusses.
Current test results show that premature failures of parallel chord wooden truss structure
are caused by the tooth plates at the nodes being pulled out of the wood. However, there are few
research results on the placement of truss members. Therefore, a method for detecting the
influence of adjusting distances between web members on the bearing capacity of a parallel
chord wooden truss is needed.
In order to solve the above-mentioned problems, this invention provides a method for
detecting the influence of adjusting distances between web members on the bearing capacity of
parallel chord wooden trusses. The method studies the placement of truss members and adopts
static loading tests, which provide theoretical basis for quality control and strength control of
light wooden trusses.
In one aspect, the present invention provides a method for detecting the influence of
adjusting distances between web members on the bearing capacity of parallel chord wooden
trusses, which includes the following steps:
S1, applying the Smsolver mechanics solver model to analyze and calculate a variation range
of distances between web member nodes of a parallel chord wooden truss, axial forces of chords
and web members, and a distribution of truss bending moments, and evaluating possible failure
modes and locations to provide theoretical support for truss form designing and bearing capacity
tests;
S2, using devices including one DH5908 wireless dynamic strain acquisition system, one
laptop, one set of loading beams and brackets, five dial indicators, one DY2200-K1T2 force sensor,
fifty-six 20mm gauge length strain gauges;
S3, adopting a hydraulic manual loading method to load the parallel chord wooden truss
synchronously at designated positions, wherein a graded loading system is used for preloading
the parallel chord wooden truss before a formal loading;
S4, measuring upper chord internodes, lower chord internodes, the maximum deflection of
a lower chord, the ultimate deflection of the truss, and a axial strain of the truss; and
S5, observing failure characterizations, analyzing failure modes, and obtaining an effective
node spacing and component failure mode in the design of SPF parallel chord wood trusses.
In some embodiments, at S2 the deformation of the parallel chord wooden truss does not
exceed 0.5-1.5 mm.
In some embodiments, at S2 a dead load is 1 .75-1 .85 KN/m 2, and a live load is 2 .0-3 .0
KN/m 2 .
In some embodiments, a distance between two trusses is 400-410 mm.
In some embodiments, at S2 the parallel chord wooden truss has a span of 2 m and a designed
load of 4.578 KN.
In some embodiments, during the preloading, one grade is 0 .65-0 .75KN in the graded
loading system, and one grade is loaded every 4-6 min.
In some embodiments, one grade is unloaded every 4-6 min until there is no load, and then
the no load status is maintained for 25-35 min.
In some embodiments, during the formal loading, one grade is 0 .65-0 .75 KN, and one grade
is loaded every 4-6 min.
In some embodiments, the load on the parallel chord wooden truss drops to 70-90% of a
peak load when a node of the parallel chord wooden truss splits.
Compared with the prior art, beneficial effects of the present invention include: the present
invention can effectively solve the problems encountered in construction caused by span control
being unable to arrange the web members sites, it adopts static loading tests and is in
compliance with "Wood Structure Design Specification" (GB50005-2017) and "Technical
Specification for Light Wood Trusses" (JGJ/T 265-2012) when designing and processing parallel
chord wooden truss, and it provides a theoretical basis for quality control and strength control of
light wood trusses.
The accompanying drawings are used to provide a further understanding of the present
invention, and constitute a part of the specification. Together with the embodiments of the
present invention, the drawings are used to explain the present invention and do not constitute a
limitation to the present invention. Among the drawings:
Figure 1 is a schematic flow chart of the present invention;
Figure 2 is a schematic diagram of a first test model of the present invention;
Figure 3 is a schematic diagram of a second test model of the present invention;
Figure 4 is a schematic flow chart of the present invention.
The technical solutions in the embodiments of the present invention will be clearly and
completely described below in conjunction with the accompanying drawings in the embodiments
of the present invention. Obviously, the described embodiments are only a part of the
embodiments of the present invention, rather than all the embodiments. Based on the
embodiments of the present invention, all other embodiments obtained by those of ordinary skill
in the art without creative work shall fall within the protection scope of the present invention.
Embodiment 1
A method for detecting the influence of adjusting distances between web members on the
bearing capacity of a parallel chord wooden truss, comprising:
S1, applying the Smsolver mechanics solver model to analyze and calculate a variation range
of distances between web member nodes of a parallel chord wooden truss, axial forces of chords
and web members, and a distribution of truss bending moments, and evaluating possible failure
modes and locations to provide theoretical support for truss form designing and bearing capacity
tests;
S2, using devices including one DH5908 wireless dynamic strain acquisition system, one
laptop, one set of loading beams and brackets, five dial indicators, one DY2200-K1T2 force sensor,
fifty-six 20mm gauge length strain gauges;
S3, adopting a hydraulic manual loading method to load the parallel chord wooden truss
synchronously at designated positions, wherein a graded loading system is used for preloading
the parallel chord wooden truss before a formal loading;
S4, measuring upper chord internodes, lower chord internodes, the maximum deflection of
a lower chord, the ultimate deflection of the truss, and a axial strain of the truss; and
S5, observing failure characterizations, analyzing failure modes, and obtaining an effective
node spacing and component failure mode in the design of SPF parallel chord wood trusses.
At Step S2 of the method for detecting the influence of adjusting distances between web
members on the bearing capacity of a parallel chord wooden truss, the deformation of the truss
doesn't not exceed 0.5 mm.
At Step S2 of the method for detecting the influence of adjusting distances between web 2 members on the bearing capacity of a parallel chord wooden truss, a dead load is 1.75 KN/m
, 2 and a live load is 2 .0 KN/m .
At Step S2 of the method for detecting the influence of adjusting distances between web
members on the bearing capacity of a parallel chord wooden truss, a distance between two
trusses is 400 mm.
At Step S2 of the method for detecting the influence of adjusting distances between web
members on the bearing capacity of a parallel chord wooden truss, the parallel chord wooden
truss has a span of 2 m and a designed load of 4.578 KN.
In the method for detecting the influence of adjusting distances between web members on
the bearing capacity of a parallel chord wooden truss, during the preloading, one grade is
.65KN in the graded loading system, and one grade is loaded every 4 min.
In the method for detecting the influence of adjusting distances between web members on
the bearing capacity of a parallel chord wooden truss, one grade is unloaded every 4 min until
there is no load, and then the no load status is maintained for 25 min.
In the method for detecting the influence of adjusting distances between web members on
the bearing capacity of a parallel chord wooden truss, during the formal loading, one grade is
.65 KN, and one grade is loaded every 4 min.
In the method for detecting the influence of adjusting distances between web members on
the bearing capacity of a parallel chord wooden truss, the load on the parallel chord wooden
truss drops to 70 %of a peak load when a node of the parallel chord wooden truss splits.
Embodiment 2
A method for detecting the influence of adjusting distances between web members on the
bearing capacity of a parallel chord wooden truss, comprising:
S1, applying the Smsolver mechanics solver model to analyze and calculate a variation range
of distances between web member nodes of a parallel chord wooden truss, axial forces of chords
and web members, and a distribution of truss bending moments, and evaluating possible failure
modes and locations to provide theoretical support for truss form designing and bearing capacity
tests;
S2, using devices including one DH5908 wireless dynamic strain acquisition system, one
laptop, one set of loading beams and brackets, five dial indicators, one DY2200-K1T2 force sensor,
fifty-six 20mm gauge length strain gauges;
S3, adopting a hydraulic manual loading method to load the parallel chord wooden truss
synchronously at designated positions, wherein a graded loading system is used for preloading
the parallel chord wooden truss before a formal loading;
S4, measuring upper chord internodes, lower chord internodes, the maximum deflection of
a lower chord, the ultimate deflection of the truss, and a axial strain of the truss; and
S5, observing failure characterizations, analyzing failure modes, and obtaining an effective
node spacing and component failure mode in the design of SPF parallel chord wood trusses.
At Step S2 of the method for detecting the influence of adjusting distances between web
members on the bearing capacity of a parallel chord wooden truss, the deformation of the truss
doesn't not exceed 1.0 mm.
At Step S2 of the method for detecting the influence of adjusting distances between web 2 members on the bearing capacity of a parallel chord wooden truss, a dead load is 1.80 KN/m ,
2 and a live load is 2 .5 KN/m .
At Step S2 of the method for detecting the influence of adjusting distances between web
members on the bearing capacity of a parallel chord wooden truss, a distance between two trusses is 405 mm.
At Step S2 of the method for detecting the influence of adjusting distances between web
members on the bearing capacity of a parallel chord wooden truss, the parallel chord wooden
truss has a span of 2 m and a designed load of 4.578 KN.
In the method for detecting the influence of adjusting distances between web members on
the bearing capacity of a parallel chord wooden truss, during the preloading, one grade is 0 .70
KN in the graded loading system, and one grade is loaded every 5 min.
In the method for detecting the influence of adjusting distances between web members on
the bearing capacity of a parallel chord wooden truss, one grade is unloaded every 5 min until
there is no load, and then the no load status is maintained for 30 min.
In the method for detecting the influence of adjusting distances between web members on
the bearing capacity of a parallel chord wooden truss, during the formal loading, one grade is
.70 KN, and one grade is loaded every 5 min.
In the method for detecting the influence of adjusting distances between web members on
the bearing capacity of a parallel chord wooden truss, the load on the parallel chord wooden
truss drops to 80 %of a peak load when a node of the parallel chord wooden truss splits.
Embodiment 3
A method for detecting the influence of adjusting distances between web members on the
bearing capacity of a parallel chord wooden truss, comprising:
S1, applying the Smsolver mechanics solver model to analyze and calculate a variation range
of distances between web member nodes of a parallel chord wooden truss, axial forces of chords
and web members, and a distribution of truss bending moments, and evaluating possible failure
modes and locations to provide theoretical support for truss form designing and bearing capacity
tests;
S2, using devices including one DH5908 wireless dynamic strain acquisition system, one
laptop, one set of loading beams and brackets, five dial indicators, one DY2200-K1T2 force sensor, fifty-six 20mm gauge length strain gauges;
S3, adopting a hydraulic manual loading method to load the parallel chord wooden truss
synchronously at designated positions, wherein a graded loading system is used for preloading
the parallel chord wooden truss before a formal loading;
S4, measuring upper chord internodes, lower chord internodes, the maximum deflection of
a lower chord, the ultimate deflection of the truss, and a axial strain of the truss; and
S5, observing failure characterizations, analyzing failure modes, and obtaining an effective
node spacing and component failure mode in the design of SPF parallel chord wood trusses.
At Step S2 of the method for detecting the influence of adjusting distances between web
members on the bearing capacity of a parallel chord wooden truss, the deformation of the truss
doesn't not exceed 1.5 mm.
At Step S2 of the method for detecting the influence of adjusting distances between web 2 members on the bearing capacity of a parallel chord wooden truss, a dead load is 1.85 KN/m
, 2 and a live load is 3.0 KN/m .
At Step S2 of the method for detecting the influence of adjusting distances between web
members on the bearing capacity of a parallel chord wooden truss, a distance between two
trusses is 410 mm.
At Step S2 of the method for detecting the influence of adjusting distances between web
members on the bearing capacity of a parallel chord wooden truss, the parallel chord wooden
truss has a span of 2 m and a designed load of 4.578 KN.
In the method for detecting the influence of adjusting distances between web members on
the bearing capacity of a parallel chord wooden truss, during the preloading, one grade is 0 .75
KN in the graded loading system, and one grade is loaded every 6 min.
In the method for detecting the influence of adjusting distances between web members on
the bearing capacity of a parallel chord wooden truss, one grade is unloaded every 6 min until
there is no load, and then the no load status is maintained for 35 min.
In the method for detecting the influence of adjusting distances between web members on
the bearing capacity of a parallel chord wooden truss, during the formal loading, one grade is
.75 KN, and one grade is loaded every 6 min.
In the method for detecting the influence of adjusting distances between web members on
the bearing capacity of a parallel chord wooden truss, the load on the parallel chord wooden
truss drops to 90 %of a peak load when a node of the parallel chord wooden truss splits.
The ultimate load size of the parallel chord wooden truss under the two working conditions
differs by 8-10KN, and the ultimate bearing capacity exceeds the design load several times,
which shows there is a large strength reserve, and that the parallel chord wooden truss has a
good bearing performance. The average value of the ultimate load of a truss with an inter-node
spacing of 0 mm is 25.38KN, and the coefficient of variation is 5.79%. The average value of the
ultimate load of a truss with an inter-node spacing of 65mm is 16.70KN, and the coefficient of
variation is 5.88%. The load is 1.5 times higher than that of a truss with an inter-node spacing of
mm. Under the two working conditions, under the ultimate load, the tooth plate is pulled out
and damaged, and there is no wood splitting. By observing the deflection values at the mid-span
and two loading points of the truss during the ultimate load, it can be found that the values of
the truss with Omm inter-node spacing are not much different, and the deformation shows an
overall downward trend. Compared with the truss with an inter-node spacing of 65 mm, the
mid-span deformation of this working condition is slightly smaller than that of the Omm
inter-node truss. The mid-span deformation and the deflection values at the two loading points
are 1.5 times different, which is related to a large distance between the loading points; the two
loading points of the former are 37mm longer than the latter, which increases the difficulty of the
mm inter-node truss under stress. Comparing the deformation of the truss under the two
conditions, it can be seen that the overall deformation of the Omm truss is smaller and it has a
higher bearing capacity. And a comprehensive analysis shows that within 3 times the design load
range, the relationship between load and deflection is a linear positive correlation. Through
modeling of the truss under the design load under the two working conditions, the distribution
of the structural force form and internal force is obtained, and the damage position of the
parallel chord wooden truss is obtained at the end node, the middle of the span, and the lower end of the loading point. The obtained results are consistent with the actual experiment. The model can effectively solve the problems encountered in construction caused by span control being unable to arrange the web members.
The load-deflection curve of the truss basically increases linearly, but certain wave troughs
are generated at the loading points at both ends. The truss load is a symmetrical force. In theory,
the deformation on both sides should be symmetrical, but the deflections at the left and right
support nodes are quite different, which is related to the properties of the material. Wood is a
non-homogeneous natural material. Therefore when it has a large span, its edge will warp.
Because of the warp, coupled with the uneven distribution of natural defects such as knots,
cracks, etc. in wood, uneven force distribution is resulted at both ends of the truss support. The
difference in deflection between the two loading points is small. The overall deformation of a
truss with an inter-node spacing of 0 mm will be greater than that of a truss with an inter-node
spacing of 65 mm, and the former is close to the mid-span deflection. This also reflects the
advantages of a truss with an inter-node spacing of 0 mm: strong stability and that there is no
premature tooth rise at the mid-span position. The curve of mid-span deflection increases
linearly under the same working conditions. When the truss is under load, the deformation under
a constant load increases. When the load reaches 3 times of the designed load, the curve
fluctuates, the truss nodes appear toothing, and the naked eye can see that the truss is
deforming and the deformation is gradually increasing. It can be seen that the mid-span
deflection of the truss with an inter-node spacing of 0 mm changes smoothly, and it has good
supporting capacity and local deformation resistance. When the truss with 65 mm inter-node
spacing reaches 3 times the design load, the mid-span deflection of the truss is obviously
unstable. With the gradual increase of the load, the increase rate of the mid-span deflection of
the truss also increases, and the stability is slightly worse, but the truss still has good supporting
capacity so that the truss does not cause material damage. And a comprehensive analysis shows
that within 3 times the design load range, the relationship between load and deflection is a linear
positive correlation. Through modeling of the truss under the designed load under the two
working conditions, the distribution of the structural force form and internal force is obtained,
and the damage position of the parallel chord wooden truss is obtained at the end node, the middle of the span, and the lower end of the loading point. The obtained results are consistent with the actual experiment. The model can effectively solve the problems encountered in construction caused by span control being unable to arrange the web members.
The beneficial effects of the present invention are: the present invention, by adopting the
method disclosed herein, can effectively solve the problem that span control cannot arrange web
members in the construction site, and it adopts a static loading test to provide a theoretical basis
for the quality control and strength control of light wood trusses. Finally, it should be noted that
the above descriptions are only preferred embodiments of the present invention and are not
intended to limit the present invention. Although the present invention has been described in
detail with reference to the foregoing embodiments, for those skilled in the art, it is still possible
to modify the technical solutions described in the foregoing embodiments, or equivalently
replace some of the technical features. Any modification, equivalent replacement, improvement,
etc., made within the spirit and principle of the present invention shall be included in the
protection scope of the present invention.
Claims (9)
1. A method for detecting the influence of adjusting distances between web members on the
bearing capacity of a parallel chord wooden truss, the method comprising:
S1, applying the Smsolver mechanics solver model to analyze and calculate a variation range
of distances between web member nodes of a parallel chord wooden truss, axial forces of chords
and web members, and a distribution of truss bending moments, and evaluating possible failure
modes and locations to provide theoretical support for truss form designing and bearing capacity
tests;
S2, using devices including one DH5908 wireless dynamic strain acquisition system, one
laptop, one set of loading beams and brackets, five dial indicators, one DY2200-K1T2 force sensor,
fifty-six 20mm gauge length strain gauges;
S3, adopting a hydraulic manual loading method to load the parallel chord wooden truss
synchronously at designated positions, wherein a graded loading system is used for preloading
the parallel chord wooden truss before a formal loading;
S4, measuring upper chord internodes, lower chord internodes, the maximum deflection of
a lower chord, the ultimate deflection of the truss, and an axial strain of the truss; and
S5, observing failure characterizations, analyzing failure modes, and obtaining an effective
node spacing and component failure mode in the design of SPF parallel chord wood trusses.
2. The method according to claim 1, wherein at S2 the deformation of the parallel chord wooden
truss is smaller than 0.5-1.5 mm.
3. The method according to claim 1, wherein at S2 a dead load is 1 .75-1 .85 KN/m 2, and a live
2 load is 2.0-3.0 KN/m .
4. The method according to claim 1, wherein a distance between two trusses is 400-410 mm.
5. The method according to claim 1, wherein at S2 the parallel chord wooden truss has a span of
2 m and a designed load of 4.578 KN.
6. The method according to claim 1, wherein during the preloading, one grade is 0 .65-0 .75KN in the graded loading system, and one grade is loaded every 4-6 min.
7. The method according to claim 1, wherein one grade is unloaded every 4-6 min until there is
no load, and then the no load status is maintained for 25-35 min.
8. The method according to claim 1, wherein during the formal loading, one grade is 0 .65-0 .75
KN, and one grade is loaded every 4-6 min.
9. The method according to claim 1, wherein the load on the parallel chord wooden truss drops
to 70-90% of a peak load when a node of the parallel chord wooden truss splits.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113970476A (en) * | 2021-12-07 | 2022-01-25 | 中建东设岩土工程有限公司 | Pressurization type rock-soil bearing capacity testing device |
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2021
- 2021-04-19 AU AU2021102015A patent/AU2021102015A4/en not_active Ceased
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113970476A (en) * | 2021-12-07 | 2022-01-25 | 中建东设岩土工程有限公司 | Pressurization type rock-soil bearing capacity testing device |
| CN113970476B (en) * | 2021-12-07 | 2024-01-12 | 中建东设岩土工程有限公司 | Pressurized rock-soil bearing capacity testing device |
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