Background technology
In recent years, natural calamity is increasing, and particularly coastal area typhoon and landlocked mountain area ice and snow disaster are more frequent, and transmission of electricity takes place frequently with the bar of communication line reinforced concrete annular rod, disconnected bar phenomenon, causes serious economy loss and social influence.Trace it to its cause, mainly be China's transmission of electricity reinforced concrete annular rod design or foundation old standard a large amount of with communication line, it is reasonable inadequately to construct, its structure is, be made of concrete and reinforcing bar, consider operating mode and manufacturing cost problem, normally the cross section diminishes old bar type gradually along with the increase of height, but reinforcing bar is to adopt the pass-through type configuration in whole bar, that is to say that the reinforcing bar at whole bar different cross section place is the same.The bar type of this structure, because it is inhomogeneous that each section of bar is subjected to moment of flexure, the bar section that is positioned at the bottom is stressed big, and superposed bar section is stressed less, the arrangement of reinforcement of design bar is in order to guarantee that (horizontal maximum load operating mode is the control operating mode of design annular rod, carries out corresponding sectional reinforcement according to the maximal bending moment of its generation bottom of bar (usually) in the bar bottom.) have enough bendings resistance, be with the bar bottom serve as the configuration foundation, this has just caused the bar section supporting capacity affluence on top, cause the waste of upper bar section arrangement of reinforcement, increased manufacturing cost, though present old bar type has also adopted the method for variable cross-section to reduce the supporting capacity affluence on bar top, but because reinforcing bar is a wildcard, just bar top is the same with the reinforcing bar of bottom, this just makes the supporting capacity affluence on bar top still can't be settled properly, make manufacturing cost still high, make that also the relative top of bearing capacity affluence degree of bar bottom is less than normal simultaneously, cause the anti-disaster ability of old bar type quite weak.
Summary of the invention
The objective of the invention is to overcome the deficiencies in the prior art part, and a kind of improved disaster-resistant reinforced concrete annular rod that can significantly improve opposing disaster overload capacity, can reduce production costs, help applying is provided.
A kind of improved disaster-resistant reinforced concrete annular rod, its structural feature is: the outer peripheral face in the annular rod bottom adds stressed plate.
Outer peripheral face in the annular rod bottom adds stressed plate, so just can improve the intensity of annular rod bottom, increases its bending resistance.Like this when the reinforcing steel bar bear of the whole annular rod of design, just top and bottom can be separated respectively and consider, only need under the stressing conditions that satisfies annular rod top, to set logical muscle (described logical muscle refers to the reinforcing bar that connects whole annular rod), and the deficiency that the bottom is stressed is by adding the bending resistance that stressed plate improves the bottom in the bottom, so concrete annular rod of this structure, can reduce production costs, avoid the wasting of resources, can significantly improve simultaneously the ability of the opposing disaster of annular rod again, the push rod that helps this concrete annular rod is used.
The arrangement that outer peripheral face in the annular rod bottom adds stressed plate has a lot, a kind ofly is: the outer peripheral face at annular rod is provided with stressed plate at interval.
Another kind is: the outer peripheral face complete cycle face at annular rod all is provided with stressed plate.
The setting of described stressed plate on annular rod lower, outer perimeter face: or it is for stressed plate is integral the formula structure with the annular rod moulding by casting, itself or for after the annular rod moulding, again it is lock onto on the annular rod.
Stressed plate and annular rod when one-body molded, also can set up the shearing resistance peg on stressed plate.
On stressed plate, set up the shearing resistance peg, can improve the adhesion stress between stressed plate and the concrete.
The annular rod lower length of setting up stressed plate is a benchmark with the stressed section of the least favorable of annular rod, adds the longitudinal stress plate of certain-length about the cross section in the certain limit.
Definite step in described least favorable cross section is as follows:
1, annular bar position of fixity is definite relevant to its restraint condition with ground, and position of fixity is generally the maximal bending moment place.
2, the most ineffective section is a cross section outward flange stress σ maximum, σ=M/W,
Here the moment of flexure of M=∑ F*L section
W=π d
1 3(1-(d
2/ d
1)
4Cross section)/32 composite bending modulus
d
1The cross section external diameter
d
2The cross section internal diameter,
d
2, d
1Along with height change.
Therefore σ=M/W exists a maximum value, by numerical analysis, can obtain the least favorable section.
Locate to be benchmark with least favorable cross section (cross section of outward flange normal stress maximum), upwards strengthening length is h
1h
1The following principle of definite foundation of length:
Suppose that common section of the new bar type (common section for not adding that section annular rod of stressed plate) and the ratio of reinforcement section (referring to that section annular rod that outer peripheral face the is set up stressed plate) area of reinforcement and the elongated area of reinforcement of old bar type are n (0.5<n<1), adjustment by the n value, as: n=0.6,0.7,0.8.。。, all can obtain the h of a minimum
1 nValue, and satisfy the interface place can resist this cross section near the reinforcing bar of common cross-sectional configurations actual moment of flexure.Then to these feasible h
1 nCompare, get the h of steel using amount minimum
1 n, be and strengthen length h
1
Downward reinforcement length is h
2, consider that maximal bending moment and least favorable cross-sectional distance are more or less the same, can be enhanced to the bottom of bar or near the bottom.
In sum, the following compared to existing technology advantage of the present invention:
At first, determine to strengthen the length of section according to the excursion requirement in the complete stressed cross section of bar least favorable.Common then section according to design load value configuration reinforcement.Because common section maximum internal force reduces, cause reducing than old type bar quantity of reinforcement.Strengthen at last then on the basis of common section reinforcing bar, arranging outer shroud reinforcement stressed plate in the section, and improve stressed plate and concrete adhesion stress, satisfy cross-sectional strength simultaneously and can resist maximal bending moment by the shearing resistance peg.The present invention can reduce the needed quantity of reinforcing bar, reduces production costs, and improves anti-disaster ability, and the push rod that helps annular rod of the present invention is used.
The specific embodiment
Below in conjunction with embodiment the present invention is described in more detail.
Embodiment 1
A kind of improved disaster-resistant reinforced concrete annular rod as Figure 1-3, add stressed plate 1 at annular rod lower, outer perimeter face, this stressed plate is the outer peripheral face complete cycle setting along the annular rod bottom, and on stressed plate, have additional shearing resistance peg 2, and make stressed plate and annular rod one moulding by casting, the annular rod lower length of setting up stressed plate is a benchmark with the stressed section of the least favorable of annular rod, adds the longitudinal stress plate of certain-length about the cross section in the certain limit.Definite step in described least favorable cross section is as follows: (as Fig. 4)
Determining of 1 annular bar position of fixity is relevant to its restraint condition with ground, and position of fixity is generally the maximal bending moment place.
2 the most ineffective sections are cross section outward flange stress σ maximum, σ=M/W,
Here the moment of flexure of M=∑ F*L section
W=π d
1 3(1-(d
2/ d
1)
4Cross section)/32 composite bending modulus
d
1The cross section external diameter
d
2The cross section internal diameter,
d
2, d
1Along with height change.
Therefore σ=M/W exists a maximum value, by numerical analysis, can obtain the least favorable section.
Locate to be benchmark with least favorable cross section (cross section of outward flange normal stress maximum), upwards strengthening length is h
1h
1The following principle of definite foundation of length:
The ratio of supposing common section of new bar type and the reinforcement section area of reinforcement and the elongated area of reinforcement of old bar type is n (0.5<n<1), by the adjustment of n value, as: n=0.6,0.7,0.8 ..., all can obtain. and the h of a minimum
1 nValue, and satisfy the interface place can resist this cross section near the reinforcing bar of common cross-sectional configurations actual moment of flexure.Then to these feasible h
1 nCompare, get the h of steel using amount minimum
1 n, be and strengthen length h
1
Downward reinforcement length is h
2, consider that maximal bending moment and least favorable cross-sectional distance are more or less the same, can be enhanced to the bottom of bar or near the bottom.
It is same as the prior art that present embodiment is not stated part.