CN103324842A - Method for positioning temporary supporting point of large structure base layer deck piece - Google Patents

Abstract

The invention discloses a method for positioning a temporary supporting point of a large structure base layer deck piece. The method comprises the following steps of (1) confirming a severely-deformed rectangular region required to be supported temporarily in the deck piece; (2) optionally selecting one point in the confirmed rectangular region and using the point as the one-time temporary supporting point, using position coordinates of the one-time temporary supporting point as design variables, and then adopting a zero-order optimization method to calculate position coordinates of an optimal supporting point in the rectangular region through iteration optimizing; (3) selecting a main beam cross point closest to the position coordinates of the optimal supporting point in the rectangular region and using the cross point as the final temporary supporting point. The method has the advantages that the settling volume of a structure can be remarkably decreased, improvement of the stability of a steel structure is facilitated, the design time is shortened, and the design is scientific and reasonable.

Description

Large structure deck of cellar sheet temporary supporting independent positioning method

Technical field

The present invention relates to the measurement and positioning method, particularly relate to large structure deck of cellar sheet temporary supporting independent positioning method.

Background technology

On the sheet of large structure deck of cellar, because the weight of steel construction large (one deck just has about the hundreds of ton usually), and build and normally carry out on the subgrade basis, so ground can produce sedimentation.Owing to reasons such as structures, the sedimentation of each spud leg also can be different simultaneously.If differential settlement is apart from excessive, just steel construction piece may produce the danger such as rollover between each spud leg.Engineering equipment is installed on the girder steel, and girder steel also can produce distortion, if surpassed the yield limit of steel, girder steel can produce plastic yield, and this is definitely unallowed, so be necessary distortion is optimized design, namely increases temporary supporting at deck plate.

Summary of the invention

The object of the invention is to overcome the deficiency of prior art, a kind of settling amount that can significantly reduce works is provided, be conducive to improve the large structure deck of cellar sheet temporary supporting independent positioning method of the steadiness of steel construction.

In order to achieve the above object, the technical solution used in the present invention is:

Large structure of the present invention deck of cellar sheet temporary supporting independent positioning method, it may further comprise the steps:

(1) determines the large rectangular area that needs to increase temporary supporting of distortion in the deck plate;

(2) in selected rectangular area, choose arbitrarily a bit as a temporary supporting point, with the position coordinates of a temporary supporting point as design variable, then adopt the zeroth order optimization method, by Optimized Iterative, calculate optimum supporting point position coordinate in the rectangular area;

(3) in the rectangular area, choose with the nearest girder point of crossing of optimum supporting point position coordinate as final temporary supporting point.

The invention has the advantages that: can significantly reduce the settling amount of works by this method, be conducive to improve the steadiness of steel construction, reduce design time, make the more science, reasonable that designs.

Description of drawings

Accompanying drawing is the schematic diagram of the deck plate that relates in the sheet temporary supporting independent positioning method of large structure of the present invention deck of cellar.

Embodiment

Describe the present invention below in conjunction with the drawings and specific embodiments.

This large structure deck of cellar sheet temporary supporting independent positioning method as shown in the figure, it may further comprise the steps: (1) determines the large rectangular area that needs to increase temporary supporting of distortion in the deck plate, the zone 5 that is represented by dotted lines among the figure; First, second, third, fourth girder point of crossing 1,2,3,4 is arranged in the rectangular area.(2) in selected rectangular area, choose arbitrarily a bit as a temporary supporting point, as design variable, then adopt the zeroth order algorithm with the position coordinates of a temporary supporting point, calculate optimum supporting point position coordinate in the rectangular area by Optimized Iterative; True origin among the figure is the lower-left point in the rectangular area.(3) in the rectangular area, choose with the nearest girder point of crossing of optimum supporting point position coordinate as final temporary supporting point.The principle of the zeroth order optimization method in the described step (2) is: the match objective function, then utilize penalty function to convert restricted minimization problem to unconstrained problem, in the approximate enterprising row iteration of penalty function, until objective function convergence, thereby obtain the optimal design variable, even the optimum supporting point position of works deflection minimum.

Embodiment 1

(1) analyzes the large structure deck plate is stressed by the ANSYS finite element analysis software, determine the large rectangular area that needs to increase temporary supporting of distortion in the deck plate;

(2) in selected rectangular area, choose arbitrarily a bit as a temporary supporting point, as design variable, then adopt the zeroth order optimization method to calculate optimum supporting point position coordinate in the rectangular area with the position coordinates of a temporary supporting point;

Concrete grammar is:

1. set up the mathematical model of optimal design

(1) determines design variable

Delimit the large rectangular area that needs to increase temporary supporting of distortion in the deck plate, set up rectangular coordinate system, as shown in Figure 1.1,2,3,4 girder point of crossing wherein, 5 is the rectangular area of delimiting.Distance is a between the setting border, the left and right sides, rectangular area, and distance is b between the up-and-down boundary.

Any selected point A is as a temporary supporting point in the zone, with the position coordinates of this point as design variable, that is:

X＝[x ₁,x ₂] ^T＝[x,y] ^T

In the formula, x ₁---the horizontal ordinate of temporary supporting point A;

x ₂---the ordinate of temporary supporting point A.

(2) determine the constraint function that A is ordered

A. performance constraints condition:

The node stress σ that temporary supporting is pointed out establishes σ in the allowable stress range of structure _cBe the structure permissible stress, then have:

σ≤σ _c

The mathematic(al) representation that obtains thus constraint function is:

g ₁(x)＝σ-σ _c≤0

B. range constraint condition:

The constraint of the design variable (position of a temporary supporting) that the present invention is selected just belongs to boundary constraint, and then the mathematic(al) representation of design variable boundary constraint function is:

$\left\{\begin{array}{c}{g}_2\left(x\right)=-x\≤0\\ g_3\left(x\right)x-a\≤0\\ g_4\left(x\right)=x-y\≤0\\ \end{array}\right.$

g ₅(x)＝y-b≤0

G in the formula ₂(x), g ₃(x), g ₄(x), g ₅The position constraint of the upper and lower, left and right of (x) ordering for A.

(3) determine objective function minF (x)

Maximum deformation value δ is as objective function, and maximum distortion is minimum.

(4) set up optimized mathematical model

minF(x)

X＝[x ₁,x ₂] ^T＝[x,y] ^T

s.t.g _u(x)≤0 u=1,2,…,5

g _u(x) this function is changed lack bracket half, do not have other problems

3. optimization method.

(1) match objective function

In the deck module zone of choosing, choose n discrete temporary supporting point, the ANSYS finite element analysis is carried out in malformation after successively each temporary supporting point being increased, set up the model of the rammer soil base at large structure and place thereof, divide by grid, imposed load carries out FEM (finite element) calculation, and result of calculation carried out stress and deformation analysis, extract maximum deformation quantity δ.

According to principle of least square method match deflection expression formula, use objective function

The expression maximum deformation quantity then has:

$\hat{f}=a_0+\underset{i=1}{\overset{2}{\mathrm{\Σ}}}{a}_i{x}_i+\underset{i=1}{\overset{2}{\mathrm{\Σ}}}\underset{j=1}{\overset{2}{\mathrm{\Σ}}}{b}_{\mathrm{ij}}{x}_i{x}_j$ (1)

$=a_0+a_1{x}_1+a_2{x}_2{+b}_{11}{x}_1^2+b_{12}{x}_1{x}_2+b_{22}{x}_2^2$

Come Coefficient of determination a by the weighted least-squares error _iAnd b _IjThat is:

$E^2=\underset{j=1}{\overset{n_d}{\mathrm{\Σ}}}{W}^{\left(j\right)}(f^{\left(j\right)}-{\hat{f}}^{\left(j\right)})$ (2)

In the formula, the group number of n---design variable;

W ^(j)---the weight relevant with j group design variable, desirable 1;

f ^(j)---the j that is calculated by finite element method organizes maximum deformation quantity corresponding to temporary supporting position;

---the j that is calculated by formula (1) organizes maximum deformation quantity corresponding to temporary supporting position.

According to the principle of least square, ask E ²Minimal value, get system of equations:

$\left\{\begin{array}{c}\frac{{\&PartialD;\mathrm{<figure-callout\; id="2"\; label="E"\; filenames="HDA00003326744100011.png"\; state="\{\{state\}\}">E</figure-callout>}}^2}{{\&PartialD;a}_i}=0\\ \frac{{\&PartialD;\mathrm{<figure-callout\; id="2"\; label="E"\; filenames="HDA00003326744100011.png"\; state="\{\{state\}\}">E</figure-callout>}}^2}{{\&PartialD;b}_{\mathrm{ij}}}=0\end{array}\right.$ (3)

Separate this system of equations, can get coefficient a _i, b _Ij, in generation, returned the objective function that equation can get the match form In ensuing optimizing process, whenever carry out iteration one time, then obtain one group of a that upgrades _iAnd b _Ij

(2) be converted to unconstrained optimization problem

Adopt penalty function to remove constraint, that is:

$\min F(X,p_k)=\hat{f}-p_k\underset{i=1}{\overset{5}{\mathrm{\&Sigma;}}}G\left(g_i\right)$ (4)

In the formula, G (g _i) be the penalty function of state variable constrain;

p _kBe penalty function G (g _i) penalty factor, 0＜p _k＜1, get successively p _k=1,0.1,0.01 ... the penalty function form of constraint function is as follows:

$\left\{\begin{array}{c}G\left(g_1\right)=\frac{1}{\mathrm{\&sigma;}-{\mathrm{\&sigma;}}_c}\\ G\left(g_2\right)=-\frac{1}{x_1}\\ G\left(g_3\right)=\frac{1}{x_1-a}\\ G\left(g_4\right)=\frac{1}{x_2}\\ G\left(g_5\right)=\frac{1}{x_2-b}\end{array}\right.$ (5)

To F (X, p _k) get ultimate value, to obtain the optimization solution X of this iteration ^*=[x ₁, x ₂], that is:

$\left\{\begin{array}{c}\frac{\&PartialD;F}{{\&PartialD;x}_1}=0\\ \frac{\&PartialD;F}{{\&PartialD;x}_2}=0\end{array}\right.$ (6)

(3) Optimized Iterative

A. choose initial temporary supporting position X ⁽⁰⁾, substitution formula 1 upgrades maximum deformation quantity expression formula coefficient a according to formula 2,3 _iAnd b _Ij, in generation, returns formula 1 and obtains match deflection expression formula

B. set initial penalty factor p ₀, try to achieve constraint penalty function G (g _i).

C. will And G (g _i) for returning formula 4 couples of F (X, p ₀) ask ultimate value, obtain this iteration optimization solution X ^{* (0)}And and X ^{* (0)}Corresponding

And F ⁽⁰⁾

D. getting successively the k time iteration is: X ^(k+1)=X ^{* (k)}, p _K+1=cp _k(c=0.1), proceed according to the method described above iteration, respectively must be corresponding in this

With F ^(k+1)

4. set the cycle control parameter.

Set and work as

When (τ is the tolerance of objective function σ), reach convergence state, stop cycle calculations.

5. check the implementation sequence result, list the optimized design variable, be i.e. the position coordinates of optimum temporary supporting point.

6. in the rectangular area, choose with the nearest girder point of crossing of optimum supporting point position coordinate as final temporary supporting point.

Reduce the settling amount of works by this method, the steadiness of steel construction improves.

Claims (1)

1. large structure deck of cellar sheet temporary supporting independent positioning method is characterized in that it may further comprise the steps:

(1) determines the large rectangular area that needs to increase temporary supporting of distortion in the deck plate;

(2) in selected rectangular area, choose arbitrarily a bit as a temporary supporting point, with the position coordinates of a temporary supporting point as design variable, then adopt the zeroth order optimization method, by Optimized Iterative, calculate optimum supporting point position coordinate in the rectangular area;

(3) in the rectangular area, choose with the nearest girder point of crossing of optimum supporting point position coordinate as final temporary supporting point.

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