Summary of the invention
In view of the deficiencies in the prior art, the purpose of the present invention is to provide a kind of cord clip of suspension bridge screw rod axle powers to apply
Work method enables to screw rod axle power different after constructing consistent, slides after avoiding installing Cable-clamp, improves what bridge used
Safety.
To achieve the above objectives, the technical solution adopted by the present invention is that:
A kind of cord clip of suspension bridge screw rod axle power construction method, comprising the following steps:
The propagation time t of S1, measurement ultrasound unstress state lower edge axial direction in screw rod to be installed0, bolt and nut is twisted
Tightly;
S2, using jack by screw stretching to design and construction axle power Fn50~70%, manually make the spiral shell that screws up with a wrench
Mother unloads jack;Test ultrasound is under the current stress state of inside screw along the time t of Propagation1, it is current to measure screw rod
Temperature T calculates the current axle power F of screw rod according to formula one1:
F1=k (T) (t1-t0)+b formula one
Wherein, k is with the Monomial coefficient that 1~2 test specimen is demarcated on experimental bench in a collection of screw rod, and k (T) is the temperature of k value
Correction term is spent, b is constant term:
S3, current axle power F is calculated according to formula two1To design and construction axle power FnWhen the angle, θ that is rotated relative to screw rod of nut,
Use jack tension screw rod to design and construction axle power Fn105~120%, and to screwing direction screw on nut angle, θ, unload
Jack;
Wherein, E is the elasticity modulus of nut stem material;H is the screw pitch of screw rod both ends screw thread;π is pi;D is screw rod
Nominal diameter;L is clamping length when screw rod fastens.
Based on the above technical solution, further comprising the steps of after the step S3:
Ultrasound is measured under the current stress state of inside screw along the time t of Propagation using ultrasonic testing system2, root
The current axle power F of screw rod is calculated according to formula three, determines current axle power F and design and construction axle power FnDifference be less than or equal to 5%Fn;
F=k (T-T0)(t2-t0)+b formula three.
It based on the above technical solution, further include following after the current axle power F of screw rod according to the calculating of formula three
Step: determine current axle power F and design and construction axle power FnDifference be greater than 5%Fn, repeat step S3.
Based on the above technical solution, in the step S2, using jack by screw stretching to axis of designing and constructing
Power Fn60% when, tensioning first is carried out to the screw rod being located among cord clip, tensioning is carried out to the screw rod for being located at two sides again, carried out pair
Angle construction.
Based on the above technical solution, the flatness at the screw rod both ends is less than or equal to 0.1mm.
Based on the above technical solution, use jack by screw stretching to axle power of designing and constructing in the step S2
Fn60%.
Based on the above technical solution, jack tension screw rod to design and construction axle power F is used in the step S3n
110%.
Compared with the prior art, the advantages of the present invention are as follows:
(1) cord clip of suspension bridge screw rod axle power construction method of the invention, the present invention first carry out screw rod by ultrasonic tesint
Pre- tensioning is twisted with first, and pretensioned pulling force is design and construction axle power Fn50~70%, screw rod can be fixed on current
Then position calculates the current axle power F to design and construction axle power F of screw rodnWhen the angle, θ that is rotated relative to screw rod of nut, tensioning spiral shell
Bar extremely design and construction axle power Fn110%, and to direction screw on nut angle, θ is screwed, all screw rods are tightened completely, by cord clip
Be fixed on main push-towing rope, tensioning and tightening way through the invention, can be avoided one by one by screw rod disposably by tensioning in place when,
The axle power of the screw rod of pretensioning before influencing when the screw rod construction of post-stretching, it is accurate that the axle power fastening construction of cord clip screw rod hardly results in
Ground control, stretching mode of the invention, which makes the axle power of cord clip screw rod fasten construction, can obtain accurate control, and all
After screw rod is installed, not threaded stress difference is less than 5%Fn, distribution is relatively uniform, and then avoids cord clip in use process
It is middle to slide, improve the safety that bridge uses.
(2) cord clip of suspension bridge screw rod axle power construction method of the invention is existed after the completion of tensioning using ultrasound detection ultrasound
Along the time t of Propagation under the current stress state of inside screw2, the current axle power of inside screw is calculated, due to using this hair
Bright method, screw rod are installed rear its internal axle power and FnDifference should be less than 5%Fn, therefore, if working as the interior of front screw
The axle power and F in portionnDifference be greater than 5%FnWhen, illustrate in the presence of fault: such as since the quantity of screw rod is excessive, when front screw is in a certain step
There is no tensioning in rapid or tighten, can quickly find the process omitted in construction, be remedied convenient for taking timely measure, it is ensured that rope
It presss from both sides screw rod axle power and meets design and construction requirement.
Specific embodiment
Invention is further described in detail with reference to the accompanying drawings and embodiments.
Shown in Figure 1, the embodiment of the present invention provides a kind of cord clip of suspension bridge screw rod axle power construction method, including following step
It is rapid:
In the propagation time t of unstress state lower edge axial direction in S1, ultrasonic tesint all screw rods 2 to be installed0, by screw rod
2 nut is tightened.
S2, screw rod 2 is stretched to design and construction axle power F using jackn50~70% (optimal is 60%), use thousand
When jin top carries out tensioning to screw rod 2, tensioning first carried out to the screw rod 2 being located among cord clip 1, then to be located at the screw rods 2 of two sides into
Row tensioning, is diagonally constructed;Then manually make the nut that screws up with a wrench, unload jack;Test ultrasound inside screw rod 2 when
Along the time t of Propagation under preceding stress state1, the current temperature T of measurement screw rod 2, according to calculating 2 current axis of screw rod of formula one
Power F1。
F1=k (T) (t1-t0)+b formula one
Wherein, k is with the Monomial coefficient that 1~2 test specimen is demarcated on experimental bench in a collection of screw rod 2, and k (T) is the temperature of k value
Correction term is spent, b is constant term.
S3, current axle power F is calculated according to formula two1To design and construction axle power FnWhen the angle, θ that is rotated relative to screw rod 2 of nut,
Use jack tension screw rod 2 to design and construction axle power Fn105~120% (most preferably 110%), and screwed to direction is screwed
Nut angle, θ, unloads jack, and the flatness at 2 both ends of screw rod is less than or equal to 0.1mm.
Wherein, E is the elasticity modulus of 2 material of screw rod, and h is the screw pitch of 2 both ends screw thread of screw rod, and π is pi, and d is screw rod 2
Nominal diameter;L is clamping length when screw rod 2 fastens.
S4, ultrasound is measured using ultrasonic testing system under the current stress state in 2 inside of screw rod along the time of Propagation
t2, screw rod 2 current axle power F, current axle power F and design and construction axle power F are calculated according to formula threenDifference be less than or equal to 5%Fn
When, screw rod 2 is constructed qualification, current axle power F and design and construction axle power FnDifference be greater than 5%Fn, screw rod 2 construct it is unqualified, check
Nuts and bolt it is elastic, apply prestressing force again and to be screwed to construction qualified.
F=k (T-T0)(t2-t0)+b formula three.
The present invention carries out pre- tensioning to screw rod 2 by ultrasonic tesint, first and just twists, and pretensioned pulling force is design and construction
Axle power Fn50~70%, screw rod 2 can be fixed on to current position, then calculate screw rod 2 current axle power F1 to design
Construct axle power FnWhen the angle, θ that is rotated relative to screw rod 2 of nut, tensioning screw rod 2 to design and construction axle power Fn110%, and to screwing
All screw rods 2 are tightened completely, cord clip 1 are fixed on main push-towing rope by direction screw on nut angle, θ, tensioning through the invention and
Tightening way, can be avoided one by one by screw rod 2 disposably by tensioning in place when, is first opened before being influenced when the screw rod 2 of post-stretching is constructed
The axle power of the screw rod 1 of drawing, the axle power fastening construction of screw rod 2, which hardly results in, accurately to be controlled, and stretching mode of the invention makes spiral shell
The axle power fastening construction of bar 2 can obtain accurate control, and stretching mode of the invention is installed all screw rods 2
Afterwards, not threaded 2 stress difference is less than 5%Fn, distribution is relatively uniform, and then cord clip 1 is avoided to slide in use,
Improve the safety that bridge uses.
Meanwhile the present invention is after the completion of tensioning, using ultrasound detection ultrasound along axis under the current stress state in 2 inside of screw rod
To the time t of propagation2, the current axle power inside screw rod 2 is calculated, due to use method of the invention, after being installed of screw rod 2
Its internal axle power and FnDifference should be less than 5%Fn, therefore, if when the axle power and F of the inside of front screw 2nDifference be greater than 5%
FnWhen, illustrate in the presence of fault: such as since the quantity of screw rod 2 is excessive, when front screw 2 without tensioning or is tightened in a certain step
Deng can quickly find the process omitted in construction, be remedied convenient for taking timely measure, it is ensured that the axle power of screw rod 2 meets design
Construction requirement.
In the following, invention is described in detail by a specific embodiment.
Screw rod 2 in the present embodiment selects the 8.8 grade high-strength screw rods 2 of model M39, total length 950mm, both ends spiral shell
The a length of 100mm of line, design and construct axle power FnFor 477KN, clamping length L when screw rod 2 fastens is 800mm.
Specifically includes the following steps:
A, ultrasound is measured under 2 inside unstress state of screw rod to be installed along Propagation using ultrasonic testing system
Time t0: 321353.5ns is manually tightened 2 nut of screw rod using spanner.
B, screw rod 2 is stretched to design and construction axle power F using jacknThe 60% of (477KN), i.e. 286.2KN, referring to figure
Shown in 1,2 tension sequence of screw rod is first intermediate and then both sides, diagonal to construct, specific order BFGCDHEA.
Manually make the nut that screws up with a wrench, unload jack, using ultrasonic testing system measure ultrasound inside screw rod 2 when
Along the time t of Propagation under preceding stress state1: 322177.3ns.
Measuring 2 Current Temperatures T of screw rod is 25 DEG C, and the current axle power F of screw rod 2 is calculated according to formula one1For 244.3KN.
The current axis power is 32.7KN less than normal than jack tension power, and the retraction of screw rod 2 causes axle power loss when being lifting jack unloading.
F1=k (T) (t1-t0)+b=244.3KN formula one
Wherein, k be demarcated on experimental bench with 1~2 test specimen in a collection of screw rod 2 when 2 temperature of screw rod is 20 DEG C it is primary
Term coefficient is 0.2705, k (T-T0) it is the temperature correction term of k value, it is constant term for 0.2878, b, is 3.9709, in practical survey
In examination, k value and b value can be obtained using conventional technical means measurement.
C, current axle power F1(244.3KN) is stretched to design and construction axle power FnNut is rotated relative to screw rod 2 when (477KN)
Angle, θ calculates to obtain 70.3 ° according to formula 2.
Wherein, E is the elasticity modulus of 2 material of screw rod, is 210GPa;H is the screw pitch of 2 both ends screw thread of screw rod, is 4mm;π is
Pi is 3.14;D is the nominal diameter of screw rod 2, is 39mm;L is clamping length when screw rod 2 fastens, and is 800mm.
D, using jack tension screw rod 2 to design and construction axle power FnThe 110% of (477KN), as 524.7KN, screw
Direction screw on nut angle, θ (70.3 °) unloads jack;Using being 322970.42ns when ultrasonic testing system measurement sound, lead to
Crossing formula (3) and calculating 2 axle power F of screw rod is 469.1KN, with design and construction axle power Fn(477KN) is compared, and less than normal 1.66%, 5%
In range, for qualification.
F=k (T-T0)(t2-t0)+b=469.1KN formula three
The present invention is not limited to the above-described embodiments, for those skilled in the art, is not departing from
Under the premise of the principle of the invention, several improvements and modifications can also be made, these improvements and modifications are also considered as protection of the invention
Within the scope of.The content being not described in detail in this specification belongs to the prior art well known to professional and technical personnel in the field.