CN102622493A - Method and device for determining maximum crack widths of ring-shaped members of round coal bunker - Google Patents

Abstract

The invention provides a method and a device for determining the maximum crack widths of ring-shaped members of a round coal bunker, which are used for solving the maximum crack widths of the ring-shaped members adopting special forms of reinforcement of the round coal bunker under the action of eccentric tension on the basis of three hypotheses in the concrete structure design code. The method comprises the steps that firstly, the size of strain of reinforcing bars on the outermost layer of a low tension side of each ring-shaped member is calculated, so as to determine whether a cross section is under low eccentric tension or high eccentric tension; afterwards, the strain and the stress of reinforcing bars on the outermost layer of a high tension side of each ring-shaped member are correspondingly obtained through solving different axial force equilibrium equations and different bending moment equilibrium equations; and finally, the stress of the reinforcing bars on the outermost layer of the high tension side of each ring-shaped member is substituted into a code formula to determine the corresponding maximum crack width. The method provides bases for the control of the crack widths of the ring-shaped members of the round coal bunker, the optimization of the quantity of reinforcement, so that the reinforcement of concrete cross sections and the structural design are more reasonable and economical.

Description

Definite method and apparatus of circular coal storehouse annular construction member maximum crack width

Technical field

The present invention relates to coal bunker annular construction member technical field, particularly relate to definite method and apparatus of a kind of circular coal storehouse annular construction member maximum crack width.

Background technology

The primary load that circular coal storehouse coal-stopping wall bears is coal wall pressure and temperature load.Under the coal piling wall pressure effect of buying securities with all one's capital, the coal-stopping wall concrete component is main to receive axial tension; Under 20 ℃ of internal-external temperature difference effects, member is main to receive curved, sees that from numerical value axial tension is more than 2 times of moment of flexure.It is thus clear that when coal wall pressure and temperature load are done the time spent simultaneously, the coal-stopping wall structure is to be main with axial tension, is attended by the eccentric tension member of bigger moment of flexure simultaneously.

When carrying out the coal-stopping wall structural design; Not only to carry out the checking of bearing capacity under the ultimate limit state; Also to carry out the crack width calculation under the normal operating condition; And latter's control usefulness often, this just needs us to be directed against the special loading characteristic of circular coal storehouse coal-stopping wall, the fracture width computing method of research eccentric tension member.

7.1.2 bar regulation in " Code for design of concrete structures ", the maximum crack width computing formula is:

${\mathrm{\ω}}_{\max }={\mathrm{\α}}_{\mathrm{cr}}\mathrm{\ψ}\frac{{\mathrm{\σ}}_s}{E_s}(1.9c_s+0.08\frac{d_{\mathrm{eq}}}{{\mathrm{\ρ}}_{\mathrm{te}}})---\left(1\right)$

Wherein, σ _sBe the stress of the reinforced concrete member longitudinal tensile reinforcing bar of the permanent combination calculation of standard of pressing load effect or the equivalent stress of prestressed concrete member longitudinal tensile reinforcing bar.Can find out that from formula (1) the crucial part that fracture width calculates is to calculate σ _s, when not considering prestressed concrete member, the stress of ordinary reinforced concrete member longitudinal tensile reinforcing bar is used σ _SqExpression, standard 7.1.4 bar is to the σ of eccentric tension member _SqComputing method following:

Eccentric tension member:

${\mathrm{\σ}}_{\mathrm{sq}}=\frac{N_k{e}^{\′}}{A_s(h_0-{a_s}^{\′})}---\left(2\right)$

From the form of formula (2), be not difficult to find σ _SqBe through to compressive region or drawn less limit longitudinal reinforcement to make a concerted effort after point gets square; Utilize the principle of equalising torque to obtain; Meaning implicit in the formula is drawn the longitudinal reinforcement of larger skirt all to be arranged in the outermost of being drawn larger skirt, and it is h that its some distance of making a concerted effort is drawn the make a concerted effort distance of point of less limit longitudinal reinforcement ₀-a _s'.Yet annular construction member (cyclic group, bulkhead and ring beam) for the circular coal storehouse; Be main mainly, need a large amount of tension reinforcement of configuration, and be limited to the requirement of bar spacing to bear axial tension; Can't these tension reinforcements all be arranged in and be drawn larger skirt; But need also need satisfy code requirement to guarantee the circular coal storehouse fracture width of annular construction member under eccentric tension in case of necessity at the total cross-section uniform reinforcement of member being drawn the extra additional bar of larger side configuration.At this moment, the longitudinal tensile reinforcing bar is made a concerted effort, and to be drawn the make a concerted effort distance of point of less limit longitudinal reinforcement be h no longer just to the some distance ₀-a _s', above-mentioned formula is no longer suitable, and if according to the computing formula of axial tension component, then can't consider the influence that pulling force is eccentric.Therefore, to the loading characteristic of circular coal storehouse annular construction member, not having ready-made crack computing formula in " Code for design of concrete structures " can use.

Summary of the invention

Based on the problems referred to above, the invention provides definite method and apparatus of a kind of circular coal storehouse annular construction member maximum crack width, to the above-mentioned arrangement of reinforcement characteristics of circular coal storehouse annular construction member, confirm the maximum crack width of circular coal storehouse annular construction member.

Definite method of a kind of circular coal storehouse annular construction member maximum crack width comprises step:

Only keep steel reinforcement cage; Do not consider concrete effect; Suppose that it is pulling force that the stress of smaller side outermost layer reinforcing bar is drawn in the cross section, and the cross section strain remains the plane, find the solution axle equilibrium equation and the moment of flexure balance equation of this moment; Draw the cross section and drawn the strain of smaller side and larger side outermost layer reinforcing bar; If it is that the hypothesis of pulling force is set up that the strain that smaller side outermost layer reinforcing bar is drawn in said cross section is drawn the stress of smaller side outermost layer reinforcing bar greater than 0 cross section, confirm that the cross section is that small eccentricity is drawn, drawn the strain of larger side outermost layer reinforcing bar to calculate the stress that larger side outermost layer reinforcing bar is drawn in the cross section according to said cross section; If it is pressure that said cross section is drawn the strain of smaller side outermost layer reinforcing bar to be drawn the stress of smaller side outermost layer reinforcing bar less than 0 cross section; Confirm that the cross section is a large eccentric tension; Suppose the triangle that is shaped as in concrete compression district; Find the solution axle equilibrium equation and the moment of flexure balance equation of this moment; Calculate the strain that larger side outermost layer reinforcing bar is drawn in the cross section according to concrete theoretical strain of tensile region, gained cross section outermost and compressive region outermost concrete strain, drawn the strain of larger side outermost layer reinforcing bar to calculate the stress that larger side outermost layer reinforcing bar is drawn in the cross section according to said cross section again;

The stress of larger side outermost layer reinforcing bar is drawn in said cross section when small eccentricity is drawn; Or the computing formula of being drawn the stress substitution maximum crack width of larger side outermost layer reinforcing bar of the said cross section during large eccentric tension, find the solution the maximum crack width of circular coal storehouse annular construction member.

Definite device of a kind of circular coal storehouse annular construction member maximum crack width comprises:

The size eccentric tension is confirmed the unit; Be used for only keeping steel reinforcement cage; Do not consider concrete effect, suppose that it is pulling force that the stress of smaller side outermost layer reinforcing bar is drawn in the cross section, and the cross section strain remains the plane; Find the solution axle equilibrium equation and the moment of flexure balance equation of this moment; Drawing the cross section and drawn the strain of smaller side and larger side outermost layer reinforcing bar, is that the hypothesis of pulling force is set up if the strain that smaller side outermost layer reinforcing bar is drawn in said cross section draws the stress of smaller side outermost layer reinforcing bar greater than 0 cross section, confirms that the cross section is that small eccentricity is drawn; If said cross section is drawn the strain of smaller side outermost layer reinforcing bar to be drawn the stress of smaller side outermost layer reinforcing bar less than 0 cross section and is pressure, confirms that the cross section is a large eccentric tension;

Small eccentricity tension reinforcement stress is confirmed the unit, and being used in the cross section is small eccentricity when being drawn, and is drawn the strain of larger side outermost layer reinforcing bar to calculate the stress that larger side outermost layer reinforcing bar is drawn in the cross section according to said cross section;

The large eccentric tension reinforcement stresses is confirmed the unit; When being used for being large eccentric tension in the cross section; Suppose the triangle that is shaped as in concrete compression district; Find the solution axle equilibrium equation and the moment of flexure balance equation of this moment, calculate the strain that larger side outermost layer reinforcing bar is drawn in the cross section, drawn the strain of larger side outermost layer reinforcing bar to calculate the stress that larger side outermost layer reinforcing bar is drawn in the cross section according to said cross section again according to concrete theoretical strain of tensile region, gained cross section outermost and compressive region outermost concrete strain;

Maximum crack width is confirmed the unit; Be used for said small eccentricity tension reinforcement stress is confirmed that the cross section of unit gained drawn the stress of larger side outermost layer reinforcing bar; Perhaps said large eccentric tension reinforcement stresses confirms that the cross section of unit gained drawn the computing formula of the stress substitution maximum crack width of larger side outermost layer reinforcing bar, finds the solution the maximum crack width of circular coal storehouse annular construction member.

Definite method and apparatus of circular coal of the present invention storehouse annular construction member maximum crack width; Three supposition based on " Code for design of concrete structures "; Be used to find the solution the structure member crevices width under the eccentric tension: at first calculating the size of being drawn the strain of smaller side outermost layer reinforcing bar is that small eccentricity is drawn or large eccentric tension with definite cross section; Secondly through finding the solution different axle equilibrium equation and moment of flexure balance equation; Draw the strain and stress that is drawn larger side outermost layer reinforcing bar accordingly, will be drawn the stress substitution modular formula of larger side outermost layer reinforcing bar to obtain corresponding maximum crack width at last.The invention provides a kind of fracture width evaluation method accurately and reliably, make the deviser can be under the prerequisite that satisfies the fracture width requirement, the quantity of reinforcement size of pair cross-section and the layout of reinforcing bar be reasonably adjusted, thereby reach the design object of optimum.Therefore, the present invention makes concrete section arrangement of reinforcement, structural design more rationally with economical for the control of the fracture width of circular coal storehouse annular construction member, the optimization of quantity of reinforcement etc. provide foundation.

Description of drawings

Fig. 1 is the schematic flow sheet of definite method of circular coal of the present invention storehouse annular construction member maximum crack width;

Circular coal storehouse annular construction member schematic cross-section when Fig. 2 is drawn for small eccentricity;

Circular coal storehouse annular construction member schematic cross-section when Fig. 3 is large eccentric tension;

Fig. 4 is the structural representation of definite device of circular coal of the present invention storehouse annular construction member maximum crack width;

Fig. 5 is the operation interface of the program worked out based on definite method of circular coal of the present invention storehouse annular construction member maximum crack width.

Embodiment

Although 2010 editions " Code for design of concrete structures " do not provide the crack computing formula of uniform reinforcement member under eccentric tension, provided three basic design assumptions:

1, the cross section strain keeps the plane;

2, the concrete normal stress figure of compressive region is taken as triangle;

3, do not consider the concrete tensile strength of compressive region.

The present invention adopts above-mentioned three supposition, through finding the solution the equilibrium of forces equation, draws under any force-bearing situation and the reinforcement stresses under any reinforcement manner, thereby finds the solution maximum crack width, below in conjunction with accompanying drawing and the present invention of embodiment illustrated in detail.

Definite method of a kind of circular coal of the present invention storehouse annular construction member maximum crack width, as shown in Figure 1, comprise step:

Step S1, only keep steel reinforcement cage; Do not consider concrete effect; Suppose that it is pulling force that the stress of smaller side outermost layer reinforcing bar is drawn in the cross section; And the cross section strain remains the plane, finds the solution axle equilibrium equation and the moment of flexure balance equation of this moment, draws the strain that smaller side and larger side outermost layer reinforcing bar are drawn in the cross section;

The size of the strain of smaller side outermost layer reinforcing bar is drawn in step S2, judgement cross section, if greater than 0 entering step S3, if get into step S4 less than 0;

It is that the hypothesis of pulling force is set up that the stress of smaller side outermost layer reinforcing bar is drawn in step S3, step S1 middle section; Confirm that the cross section is that small eccentricity is drawn; Drawn the strain of larger side outermost layer reinforcing bar to calculate the stress that larger side outermost layer reinforcing bar is drawn in the cross section according to said cross section, got into step S5;

It is that the hypothesis of pulling force is false that the stress of smaller side outermost layer reinforcing bar is drawn in step S4, step S1 middle section; It is pressure that the stress of smaller side outermost layer reinforcing bar is drawn in the cross section; Confirm that the cross section is a large eccentric tension, this moment, a part of concrete was participated in pressurized, supposed the triangle that is shaped as in concrete compression district; Axle equilibrium equation and moment of flexure balance equation when finding the solution large eccentric tension; Calculate the strain that larger side outermost layer reinforcing bar is drawn in the cross section according to concrete theoretical strain of tensile region, gained cross section outermost and compressive region outermost concrete strain, and then calculate the stress that larger side outermost layer reinforcing bar is drawn in the cross section, get into step S5;

The formula of the stress substitution maximum crack width of larger side outermost layer reinforcing bar is drawn in step S5, the cross section that step S3 and step S4 are calculated gained, finds the solution the maximum crack width of circular coal storehouse annular construction member.

As a preferred embodiment; It is that pulling force is that the cross section small eccentricity is when being drawn that the stress of smaller side outermost layer reinforcing bar is drawn in step S1 hypothesis cross section; The interface synoptic diagram of circular coal storehouse annular construction member is as shown in Figure 2, and the axle equilibrium equation and the moment of flexure balance equation in cross section are followed successively by:

$N=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i---\left(3\right)$

$N\·\left({e-c}_1\right)=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i{h}_i---\left(4\right)$

In the following formula, N representes cross section suffered axle power, and n representes the reinforcing bar number of plies, and wherein, it is the 1st layer that the outermost reinforcing bar of larger side is drawn in the cross section, inwardly is followed successively by the 2nd layer, the 3rd layer ..., the n layer representes that the cross section drawn the reinforcing bar of smaller side, e representes eccentric throw, c ₁The protective layer thickness (the reinforcing bar cross section centre of form is to the distance of concrete ragged edge) of smaller side, h are drawn in the expression cross section _iThe distance of representing i layer reinforcing bar and n layer reinforcing bar, E _sThe elastic modulus of expression reinforcing bar, A _SiThe area of section of representing i layer reinforcing bar, ε _iRepresent the strain of i layer reinforcing bar.C among Fig. 2 representes that the cross section drawn the protective layer thickness of larger side.The computing formula of eccentric distance e is:

$e=\frac{M}{N}+\frac{h}{2}---\left(5\right)$

M representes moment of flexure in the formula (5), and h representes the concrete section height.

Owing to adopted plane cross-section assumption so ε _iAnd h _iAll satisfy certain linear, can specify ε ₁And ε _nBe fundamental unknown variables, ε _iAnd h _iJust can be with containing ε ₁And ε _nExpression formula show, form a linear equation in two unknowns group after substitution (3) formula and (4) formula, preferably adopt Gaussian elimination to find the solution.Draw ε ₁And ε _nAfter, to ε _nJudge with 0 size, if ε _nThe cross section is that small eccentricity is drawn for stretching strain greater than 0, the ε that draw this moment ₁～ε _nBe each layer reinforcing bar strain under the true force-bearing situation, with ε ₁Substitution formula σ _i=E _sε _iCan obtain the cross section and drawn the stress σ of larger side outermost layer reinforcing bar ₁, with σ ₁As σ _sThe maximum crack width computing formula that substitution " Code for design of concrete structures " 7.1.2 bar provides can be obtained the circular coal storehouse annular construction member maximum crack width of this moment.If ε _nLess than 0 for compressive strain, the cross section is a large eccentric tension, then need change the large eccentric tension calculation process over to.

So-called large eccentric tension is meant and has the concrete compression district.According to supposition 2, the concrete compression district is shaped as triangle, sees Fig. 3, two diagonal triangles among Fig. 3, and the triangle of band shade is represented compressive region, blank triangle is represented the tensile region.

As a preferred embodiment, during the large eccentric tension of cross section, axle equilibrium equation and moment of flexure balance equation are followed successively by:

$N=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i-\frac{1}{2}{E}_c{\mathrm{\ϵ}}_c{\mathrm{bh}}_c---\left(6\right)$

$N\·e=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i{h_i}^{\′}-\frac{1}{2}{E}_c{\mathrm{\ϵ}}_c{\mathrm{bh}}_c\·\frac{1}{3}{h}_c---\left(7\right)$

In the following formula, E _cBe concrete elastic modulus, ε _cExpression cross section compressive region outermost concrete strain, h _i' be that i layer reinforcing bar is apart from the concrete distance of compressive region outermost, h _cBe concrete compression district height, b is the concrete component width.ε among Fig. 3 ₀The concrete theoretical strain of expression tensile region outermost, h representes the concrete section height.

Equally, can suppose ε ₀And ε _cBe fundamental unknown variables, ε _i, h _iAnd h _cCan be with containing ε ₀And ε _cExpression formula represent that substitution (6) formula and (7) formula form a binary quadratic equation group, preferably find the solution through the Newton method of finding the solution Nonlinear System of Equations.Drawing ε ₀And ε _cAfter, just can obtain the strain of whole reinforcing bars.With the strain stress of being drawn larger side outermost layer reinforcing bar ₁Substitution formula σ _i=E _sε _iCan obtain the stress σ that is drawn larger side outermost layer reinforcing bar ₁, with σ ₁As σ _sThe maximum crack width computing formula that substitution " Code for design of concrete structures " 7.1.2 bar provides can be obtained the circular coal storehouse annular construction member maximum crack width of this moment.

Definite device of circular coal of the present invention storehouse annular construction member maximum crack width is the device corresponding with said method, and is as shown in Figure 4, comprising:

The size eccentric tension is confirmed the unit; Be used for only keeping steel reinforcement cage; Do not consider concrete effect, suppose that it is pulling force that the stress of smaller side outermost layer reinforcing bar is drawn in the cross section, and the cross section strain remains the plane; Find the solution axle equilibrium equation and the moment of flexure balance equation of this moment; Drawing the cross section and drawn the strain of smaller side and larger side outermost layer reinforcing bar, is that the hypothesis of pulling force is set up if the strain that smaller side outermost layer reinforcing bar is drawn in said cross section draws the stress of smaller side outermost layer reinforcing bar greater than 0 cross section, confirms that the cross section is that small eccentricity is drawn; If said cross section is drawn the strain of smaller side outermost layer reinforcing bar to be drawn the stress of smaller side outermost layer reinforcing bar less than 0 cross section and is pressure, confirms that the cross section is a large eccentric tension;

Small eccentricity tension reinforcement stress is confirmed the unit, and being used in the cross section is small eccentricity when being drawn, and is drawn the strain of larger side outermost layer reinforcing bar to calculate the stress that larger side outermost layer reinforcing bar is drawn in the cross section according to said cross section;

The large eccentric tension reinforcement stresses is confirmed the unit; When being used for being large eccentric tension in the cross section; Suppose the triangle that is shaped as in concrete compression district; Find the solution axle equilibrium equation and the moment of flexure balance equation of this moment, calculate the strain that larger side outermost layer reinforcing bar is drawn in the cross section, drawn the strain of larger side outermost layer reinforcing bar to calculate the stress that larger side outermost layer reinforcing bar is drawn in the cross section according to said cross section again according to concrete theoretical strain of tensile region, gained cross section outermost and compressive region outermost concrete strain;

Maximum crack width is confirmed the unit; Be used for said small eccentricity tension reinforcement stress is confirmed that the cross section of unit gained drawn the stress of larger side outermost layer reinforcing bar; Perhaps said large eccentric tension reinforcement stresses confirms that the cross section of unit gained drawn the computing formula of the stress substitution maximum crack width of larger side outermost layer reinforcing bar, finds the solution the maximum crack width of circular coal storehouse annular construction member.

Can know by foregoing description and Fig. 4; The size eccentric tension confirms that the unit connects small eccentricity tension reinforcement stress respectively and confirms that unit and large eccentric tension reinforcement stresses confirm the unit; Small eccentricity tension reinforcement stress confirms that unit and large eccentric tension reinforcement stresses confirm that the unit is connected maximum crack width more separately and confirms the unit, thereby has constituted this device.

As a preferred embodiment, it is under the situation of pulling force that said big or small eccentric tension determination module is drawn the stress of smaller side outermost layer reinforcing bar in the hypothesis cross section, and the axle equilibrium equation and the moment of flexure balance equation of being found the solution are followed successively by:

$N=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i---\left(3\right)$

$N\·\left({e-c}_1\right)=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i{h}_i---\left(4\right)$

In the following formula, N representes cross section suffered axle power, and n representes the reinforcing bar number of plies, and wherein, it is the 1st layer that the outermost reinforcing bar of larger side is drawn in the cross section, inwardly is followed successively by the 2nd layer, the 3rd layer ..., e representes eccentric throw, c ₁The protective layer thickness of smaller side, h are drawn in the expression cross section _iThe distance of representing i layer reinforcing bar and n layer reinforcing bar, E _sThe elastic modulus of expression reinforcing bar, A _SiThe area of section of representing i layer reinforcing bar, ε _iRepresent the strain of i layer reinforcing bar.

As a preferred embodiment, said big small eccentricity pulling force confirms that the unit also is used to adopt Gaussian elimination to find the solution axle equilibrium equation and the moment of flexure balance equation of cross section when being drawn the stress of smaller side outermost layer reinforcing bar to be pulling force.

As a preferred embodiment, said large eccentric tension reinforcement stresses is confirmed the unit in the cross section during large eccentric tension, and the axle equilibrium equation and the moment of flexure balance equation of being found the solution are followed successively by:

$N=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i-\frac{1}{2}{E}_c{\mathrm{\ϵ}}_c{\mathrm{bh}}_c---\left(6\right)$

$N\·e=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i{h_i}^{\′}-\frac{1}{2}{E}_c{\mathrm{\ϵ}}_c{\mathrm{bh}}_c\·\frac{1}{3}{h}_c---\left(7\right)$

In the following formula, E _cBe concrete elastic modulus, ε _cThe concrete strain of expression cross section compressive region outermost, h _i' be that i layer reinforcing bar is apart from the concrete distance of compressive region outermost, h _cBe concrete compression district height, b is the concrete component width.

As a preferred embodiment, axle equilibrium equation and moment of flexure balance equation when said large eccentric tension reinforcement stresses confirms that the unit also is used to adopt Newton method to find the solution the cross section large eccentric tension.

Because this device is corresponding with said method, the concrete course of work repeats no more.

In addition, computation process of the present invention relates to finding the solution of equation of higher degree group, needs programming to carry out iterative.Therefore, inventor of the present invention adopts the secondary development program VBA (Visual Basic For Application) that carries in the Excel, has worked out a program that has operation interface and has realized computing function.As shown in Figure 5; Through program interface input section height, cross-sectional width, the reinforcing bar number of plies, bar diameter; Component information such as thickness of concrete cover and strength grade of concrete; And load information such as accurate permanent value of axle power and the accurate permanent value of moment of flexure, just can find the solution and drawn and compression steel stress, and then obtain maximum crack width.The program of it should be noted that can also be imported outermost layer additional bar radical and diameter, calculates when being drawn the situation of larger side arrangement of reinforcement greater than the quantity of reinforcement that is uniformly distributed with every layer of reinforcing bar.

Definite method and apparatus of circular coal of the present invention storehouse annular construction member maximum crack width satisfies equilibrium of forces equation and compatibility of deformation equation; Therefore; The reinforcement stresses that calculates is accurately under the assumed conditions that standard provides, and the fracture width computing method that draw thus also satisfy code requirement.Calculation procedure according to this method establishment has been applied to domestic a plurality of large-diameter circular coal bin; Compare with method in the past, the fracture width of control member is optimized quantity of reinforcement better better; Make the concrete section arrangement of reinforcement more effective, structural design is reasonable more economically.

The above embodiment has only expressed several kinds of embodiments of the present invention, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to claim of the present invention.Should be pointed out that for the person of ordinary skill of the art under the prerequisite that does not break away from the present invention's design, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with accompanying claims.

Claims (10)

1. definite method of a circular coal storehouse annular construction member maximum crack width is characterized in that, comprises step:

Only keep steel reinforcement cage; Do not consider concrete effect; Suppose that it is pulling force that the stress of smaller side outermost layer reinforcing bar is drawn in the cross section, and the cross section strain remains the plane, find the solution axle equilibrium equation and the moment of flexure balance equation of this moment; Draw the cross section and drawn the strain of smaller side and larger side outermost layer reinforcing bar; If it is that the hypothesis of pulling force is set up that the strain that smaller side outermost layer reinforcing bar is drawn in said cross section is drawn the stress of smaller side outermost layer reinforcing bar greater than 0 cross section, confirm that the cross section is that small eccentricity is drawn, drawn the strain of larger side outermost layer reinforcing bar to calculate the stress that larger side outermost layer reinforcing bar is drawn in the cross section according to said cross section; If it is pressure that said cross section is drawn the strain of smaller side outermost layer reinforcing bar to be drawn the stress of smaller side outermost layer reinforcing bar less than 0 cross section; Confirm that the cross section is a large eccentric tension; Suppose the triangle that is shaped as in concrete compression district; Find the solution axle equilibrium equation and the moment of flexure balance equation of this moment; Calculate the strain that larger side outermost layer reinforcing bar is drawn in the cross section according to concrete theoretical strain of tensile region, gained cross section outermost and the concrete strain of compressive region outermost, drawn the strain of larger side outermost layer reinforcing bar to calculate the stress that larger side outermost layer reinforcing bar is drawn in the cross section according to said cross section again;

The stress of larger side outermost layer reinforcing bar is drawn in said cross section when small eccentricity is drawn; Or the computing formula of being drawn the stress substitution maximum crack width of larger side outermost layer reinforcing bar of the said cross section during large eccentric tension, find the solution the maximum crack width of circular coal storehouse annular construction member.

2. definite method of circular coal according to claim 1 storehouse annular construction member maximum crack width is characterized in that, when the cross section was drawn the stress of smaller side outermost layer reinforcing bar to be pulling force, axle equilibrium equation and moment of flexure balance equation were followed successively by:

$N=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i$

$N\·\left({e-c}_1\right)=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i{h}_i$

In the following formula, N representes cross section suffered axle power, and n representes the reinforcing bar number of plies, and wherein, it is the 1st layer that the outermost reinforcing bar of larger side is drawn in the cross section, inwardly is followed successively by the 2nd layer, the 3rd layer ..., e representes eccentric throw, c ₁The protective layer thickness of smaller side, h are drawn in the expression cross section _iThe distance of representing i layer reinforcing bar and n layer reinforcing bar, E _sThe elastic modulus of expression reinforcing bar, A _SiThe area of section of representing i layer reinforcing bar, ε _iRepresent the strain of i layer reinforcing bar.

3. definite method of circular coal according to claim 2 storehouse annular construction member maximum crack width is characterized in that, adopts Gaussian elimination to find the solution axle equilibrium equation and the moment of flexure balance equation of cross section when being drawn the stress of smaller side outermost layer reinforcing bar to be pulling force.

4. according to definite method of claim 2 or 3 described circular coal storehouse annular construction member maximum crack widths, it is characterized in that when the cross section was large eccentric tension, axle equilibrium equation and moment of flexure balance equation were followed successively by:

$N=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i-\frac{1}{2}{E}_c{\mathrm{\ϵ}}_c{\mathrm{bh}}_c$

$N\·e=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i{h_i}^{\′}-\frac{1}{2}{E}_c{\mathrm{\ϵ}}_c{\mathrm{bh}}_c\·\frac{1}{3}{h}_c$

In the following formula, E _cBe concrete elastic modulus, ε _cThe concrete strain of expression cross section compressive region outermost, h _i' be that i layer reinforcing bar is apart from the concrete distance of compressive region outermost, h _cBe concrete compression district height, b is the concrete component width.

5. definite method of circular coal according to claim 4 storehouse annular construction member maximum crack width is characterized in that, adopts Newton method to find the solution axle equilibrium equation and the moment of flexure balance equation of cross section when being large eccentric tension.

6. definite device of a circular coal storehouse annular construction member maximum crack width is characterized in that, comprising:

The size eccentric tension is confirmed the unit; Be used for only keeping steel reinforcement cage; Do not consider concrete effect, suppose that it is pulling force that the stress of smaller side outermost layer reinforcing bar is drawn in the cross section, and the cross section strain remains the plane; Find the solution axle equilibrium equation and the moment of flexure balance equation of this moment; Drawing the cross section and drawn the strain of smaller side and larger side outermost layer reinforcing bar, is that the hypothesis of pulling force is set up if the strain that smaller side outermost layer reinforcing bar is drawn in said cross section draws the stress of smaller side outermost layer reinforcing bar greater than 0 cross section, confirms that the cross section is that small eccentricity is drawn; If said cross section is drawn the strain of smaller side outermost layer reinforcing bar to be drawn the stress of smaller side outermost layer reinforcing bar less than 0 cross section and is pressure, confirms that the cross section is a large eccentric tension;

Small eccentricity tension reinforcement stress is confirmed the unit, and being used in the cross section is small eccentricity when being drawn, and is drawn the strain of larger side outermost layer reinforcing bar to calculate the stress that larger side outermost layer reinforcing bar is drawn in the cross section according to said cross section;

The large eccentric tension reinforcement stresses is confirmed the unit; When being used for being large eccentric tension in the cross section; Suppose the triangle that is shaped as in concrete compression district; Find the solution axle equilibrium equation and the moment of flexure balance equation of this moment, calculate the strain that larger side outermost layer reinforcing bar is drawn in the cross section, drawn the strain of larger side outermost layer reinforcing bar to calculate the stress that larger side outermost layer reinforcing bar is drawn in the cross section according to said cross section again according to concrete theoretical strain of tensile region, gained cross section outermost and the concrete strain of compressive region outermost;

Maximum crack width is confirmed the unit; Be used for said small eccentricity tension reinforcement stress is confirmed that the cross section of unit gained drawn the stress of larger side outermost layer reinforcing bar; Perhaps said large eccentric tension reinforcement stresses confirms that the cross section of unit gained drawn the computing formula of the stress substitution maximum crack width of larger side outermost layer reinforcing bar, finds the solution the maximum crack width of circular coal storehouse annular construction member.

7. definite device of circular coal according to claim 6 storehouse annular construction member maximum crack width; It is characterized in that; Said big or small eccentric tension confirms that it is under the situation of pulling force that the unit is drawn the stress of smaller side outermost layer reinforcing bar in the hypothesis cross section, and the axle equilibrium equation and the moment of flexure balance equation of being found the solution are followed successively by:

$N=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i$

$N\·\left({e-c}_1\right)=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i{h}_i$

In the following formula, N representes cross section suffered axle power, and n representes the reinforcing bar number of plies, and wherein, it is the 1st layer that the outermost reinforcing bar of larger side is drawn in the cross section, inwardly is followed successively by the 2nd layer, the 3rd layer ..., e representes eccentric throw, c ₁The protective layer thickness of smaller side, h are drawn in the expression cross section _iThe distance of representing i layer reinforcing bar and n layer reinforcing bar, E _sThe elastic modulus of expression reinforcing bar, A _SiThe area of section of representing i layer reinforcing bar, ε _iRepresent the strain of i layer reinforcing bar.

8. definite device of circular coal according to claim 7 storehouse annular construction member maximum crack width; It is characterized in that said big small eccentricity pulling force confirms that the unit also is used to adopt Gaussian elimination to find the solution axle equilibrium equation and the moment of flexure balance equation of cross section when being drawn the stress of smaller side outermost layer reinforcing bar to be pulling force.

9. according to definite device of claim 7 or 8 described circular coal storehouse annular construction member maximum crack widths; It is characterized in that; When said large eccentric tension reinforcement stresses confirmed that the unit is large eccentric tension in the cross section, the axle equilibrium equation and the moment of flexure balance equation of being found the solution were followed successively by:

$N=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i-\frac{1}{2}{E}_c{\mathrm{\ϵ}}_c{\mathrm{bh}}_c$

$N\·e=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{E}_s{A}_{\mathrm{si}}{\mathrm{\ϵ}}_i{h_i}^{\′}-\frac{1}{2}{E}_c{\mathrm{\ϵ}}_c{\mathrm{bh}}_c\·\frac{1}{3}{h}_c$

In the following formula, E _cBe concrete elastic modulus, ε _cThe concrete strain of expression cross section compressive region outermost, h _i' be that i layer reinforcing bar is apart from the concrete distance of compressive region outermost, h _cBe concrete compression district height, b is the concrete component width.

10. definite device of circular coal according to claim 9 storehouse annular construction member maximum crack width; It is characterized in that said large eccentric tension reinforcement stresses confirms that the unit also is used to adopt Newton method to find the solution axle equilibrium equation and the moment of flexure balance equation of cross section when being large eccentric tension.

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