JP6542012B2 - Simplified earthquake resistance evaluation method of substation outdoor steel frame - Google Patents

Description

  The present invention relates to a method for efficiently and easily evaluating the earthquake resistance of a substation outdoor steel structure (hereinafter referred to as an outdoor steel structure).

  FIG. 1 shows one form of an outdoor steel frame, which is an example of one composed of a plurality of frames (hereinafter simply referred to as a steel frame 1). FIG. 2 shows another example of the outdoor steel frame, and shows an example of a dead steel frame 1a constituted by a single flat frame.

  The columns 2 and the beams 3 are formed in a truss structure. Conventionally, the earthquake resistance evaluation of the outdoor steel structure as illustrated in FIG. 1 and FIG. 2 creates a detailed model in which the main material and belly material of the truss of the column 2 and the beam 3 are recognized, and the time history of assumed seismic waves It is common to conduct seismic response analysis and to conduct member studies. Therefore, it takes time, effort, and cost to create a detailed model and to organize and analyze analysis results for a plurality of assumed seismic waves.

In addition, in order to prepare for a large earthquake that is expected to be frequent in the future, it is particularly necessary to grasp the earthquake resistance of the existing outdoor steel structure and take measures. There is a need for a method that can evaluate earthquake resistance efficiently and simply.
There are patent documents 1 thru / or patent documents 3 as a prior art about a method of performing earthquake resistance evaluation of a structure efficiently, for example.

  Patent Document 1 is a method for evaluating the seismic performance of an existing building, which is to input data of a target building and calculate the current seismic performance evaluation value of the target building with reference to basic data of a database. .

  As the current seismic performance evaluation value, "structural earthquake resistance index value Is" as a measure of structural safety and "predicted maximum loss rate PML" as a measure of asset value etc. are calculated, but PML value is calculated based on Is value Be done. Since this Is value needs to be obtained by calculating the structural resistance and the like for each target building, if the number of evaluation targets is large, much time, labor, and cost are required.

  Patent document 2 inputs the building information and geographical information of evaluation object, and uses the data corresponding to the information of the evaluation object among the structure data of a building stored in advance, ground data, and seismic wave data, using the above-mentioned evaluation The seismic performance is evaluated by analyzing the deformation state of the target building at the time of the earthquake and making a ground diagnosis of the construction site.

  However, these prior art methods are methods for analyzing and evaluating individual buildings to be targeted individually, and the above-mentioned problems to be solved, that is, earthquake resistance to a large number of target structures efficiently and simply. It can not be said that it is a method to evaluate, and there is nothing to suggest about such a method.

  Patent document 3 is a seismic design method of a building which evaluates the damage degree of the object building to an assumption earthquake. In this method, the relationship between the interlayer deformation angle and the degree of damage is derived in advance for each category of standardized buildings by structural experiment of an actual structural model, and seismic response analysis is individually performed for the evaluation target buildings. For the earthquake motion of the designated size, input virtual seismic waves several thousands to tens of thousands of times, and calculate the probability of occurrence of the maximum interlayer deformation angle to be generated. Then, the interlayer deformation angle and damage degree In order to evaluate how much damage it will be applied to

  That is, it does not estimate only from the known information such as the dimensions and natural period of the evaluation object building. Therefore, as in Patent Documents 1 and 2, it can not be said that it is a method of evaluating the earthquake resistance efficiently and simply for a large number of target structures, and there is no suggestion about such a method.

Japanese Patent Application Publication No. 2003-147970 JP 2008-251045 A Patent No. 565 3765

  The present invention is installed in substations at many points throughout the country, and easily evaluates the earthquake resistance evaluation of a large number of existing outdoor steel structures that differ in size and shape depending on the voltage class without performing structural calculation and earthquake response analysis. It is intended to provide a method.

  The earthquake resistant simplified evaluation method of the substation outdoor steel structure of the present invention has the following configuration (refer to the numbers (1) to (7) in the flowchart shown in FIG. 9).

  First, from the eigenvalue analysis for the detailed model of the representative steel structure (for example, the model recognized to the truss member) set in each voltage class of the outdoor steel structure in advance, the beam attachment height H and the primary natural period of these representative steel structures A relational expression (for example, a regression expression) with T1 is determined ((1)).

In addition, stress analysis is performed on the detailed model of each representative steel structure by time history seismic response analysis of assumed seismic waves, and the maximum obtained from the acceleration response spectrum of assumed seismic waves for the primary natural period T1 of each representative steel structure Find a relational expression (for example, a regression expression) between the acceleration response value Ax1 ((2)) and the short-term allowable stress ratio σ / f of the member of each representative steel structure obtained from the stress analysis result (for example, regression expression) (3)). These relational expressions are programmed and stored in storage means (memory) of a computer.
Here, the short-term allowable stress ratio σ / f of the member is the ratio of the stress degree σ acting on the member to the short-term allowable stress f of the member.

Next, using these relations,
Calculating the primary natural period t1 from the beam attachment height h of the outdoor steel structure to be evaluated (hereinafter referred to as a target steel structure) belonging to each voltage class ((4));
Predicting the maximum acceleration response value ax1 of the target steel structure from the acceleration response spectrum of the assumed seismic wave using the primary natural period t1 of the target steel structure ((5));
Estimating the short-term allowable stress ratio σ / f of the target steel structure from the maximum acceleration response value ax1 of the target steel structure ((6));
A procedure ((7)) of determining whether the short-term allowable stress ratio σ / f is greater than 1 or not for seismic reinforcement
The earthquake resistance of the target steel structure will be evaluated in a simplified manner by following a series of procedures.
These series of procedures are performed by the computing means (CPU) of the computer.

  Also, in the present invention, taking advantage of the fact that the beam attachment height H of the representative steel structure of each voltage class and the primary natural period T1 are approximately linearly proportional, the beam attachment height h of the target steel structure is determined only from the first h The short-term allowable stress ratio σ / f of the target steel structure to the assumed seismic wave may be estimated by approximately determining the natural period t1.

  Moreover, in the present invention, in the outdoor steel structure which is a truss structure composed of the main column material and the belly material, only the short-term allowable stress ratio σ / f of the lowermost node of the main pillar material is evaluated instead of the belly material. You may

Representatives relation beam iron structure trims and height H as the primary natural period T1, and relationship between the maximum acceleration response value Ax1 and short allowable stress intensity ratio sigma / f representative steel structures is programmed reduction, the flop using program, we estimate short-term allowable stress intensity ratio sigma / f of the subject steel structures for seismic waves assumed.

  In the present invention, the reason why the short-term allowable stress ratio σ / f of the target steel structure to the assumed seismic wave can be estimated from each relational expression obtained from the representative steel structure set for each voltage class of the outdoor steel structure is as follows. It is.

  The inventor of the present invention has revealed for the first time that the beam attachment height H of the representative steel structure of each voltage class and the primary natural period T1 are substantially linearly proportional as a characteristic unique to the substation outdoor steel structure. In addition, the target steel structures belonging to the same voltage class as the representative steel structure are approximately the same in scale (height, span, etc.), and the primary natural period t1 of those target steel structures is close to the primary natural period T1 of the representative steel structure Therefore, by using the linear proportional relationship of the representative steel structures, it is possible to approximately determine the first-order natural period t1 only from the beam attachment height h of the target steel structures.

  That is, the eigen value analysis of the target steel structure can be omitted. Then, assuming that the primary natural period t1 is obtained, it is assumed hereinafter by applying to the T1 to Ax1 relationship (the above-mentioned procedure (5)) and the Ax1 to σ / f relationship (the above procedure (6)) for the representative steel structure. It becomes possible to estimate the short-term allowable stress ratio σ / f of the target steel structure to seismic waves.

  Further, the reason why only the short-term allowable stress ratio σ / f of the lowermost section of the main column member can be evaluated instead of the belly member is as follows. The column of the outdoor steel structure is a truss structure composed of the main column material and the belly material, and the site most susceptible to damage due to earthquake motion is the lowermost node or beam attachment in the main pillar material. The site can not be identified.

  From the viewpoint of emphasizing which of the main column material and the belly material is more important, the damage of the main column material and the lowermost node supporting its own weight is more likely to cause the outdoor steel structure to collapse than the damage of the belly material Therefore, the lowest section of the main pillar is given priority. In addition, considering simplicity, it is appropriate to limit to the lowermost section of the main column material as a simplified earthquake resistance evaluation method for outdoor steel structures.

  Since the present invention evaluates earthquake resistance according to the above-described procedure, the following effects can be obtained.

(1) As long as the beam attachment height of the target steel structure is known, the short-term allowable stress ratio to assumed seismic waves can be estimated, so it is a simple and quick method of evaluating earthquake resistance.

(2) There is no need to carry out seismic response analysis or structural calculation in a series of work for seismic assessment of the target steel structure.

(3) Since the earthquake proof margin is obtained as the reciprocal of the short-term allowable stress ratio of the member, the degree of yield (damage) can be easily compared with other target steel structures under the same standard.

(4) As mentioned above, since earthquake resistance evaluation can be made extremely efficient and simple, prioritization of earthquake resistance measures for many outdoor steel structures can be implemented quickly and economically.

(5) Therefore, it contributes greatly to the promotion of the prompt seismic strengthening of the existing outdoor steel structure and, consequently, to the prevention of the blackout due to the occurrence of the earthquake.

It is a whole perspective view showing an example of a steel structure assumed as a representative steel structure. It is a whole perspective view showing an example of a dead steel structure assumed as a representative steel structure. It is a graph which shows the relationship between the beam attachment height H of a representative steel structure, and primary intrinsic period T1. It is a graph which shows an example of the acceleration response spectrum corresponding to a primary natural period. It is a graph which shows the relationship between the acceleration response value Ax1 of the main pillar material and belly material of a representative steel frame of voltage class 500kV, and a short-term allowable stress ratio σ / f, and its regression line. It is a graph which shows the relationship between the acceleration response value Ax1 of the main pillar material and belly material of a representative steel frame of voltage class 275kV, and a short-term allowable stress ratio σ / f, and its regression line. It is a graph which shows the relationship between the acceleration response value Ax1 of the main column material and belly material of a representative steel frame of voltage class 154kV, and a short-term allowable stress ratio σ / f, and its regression line. It is a graph which shows the relationship between the acceleration response value Ax1 of the main pillar material and belly material of the representative steel frame of voltage class 66kV, and a short-term allowable stress ratio σ / f, and its regression line. It is a flowchart which shows the outline | summary of the earthquake resistance simple evaluation method of this invention.

  The present invention will be described below based on the drawings and tables. FIG. 1 is an overall perspective view of a steel structure 1 assumed as a representative steel structure. Although a plurality of electric wires 4, 4, ... (see Fig. 2) are actually connected, they are not shown. Moreover, FIG. 2 is a whole perspective view of the dead steel structure 1a which consists of a single flat frame assumed as a representative steel structure.

  In the evaluation method according to the present invention, first, as described in Table 1, representative steel structures in the form illustrated in FIG. 1 and FIG. The structure 1a) is selected, and a three-dimensional detailed model in which the main column material and the belly material of the column 2 and the beam 3 which are truss structures are recognized is created.

  The primary natural period T1 of the representative steel structure is calculated by eigen value analysis of these representative steel structures (● and 印 in FIG. 3), and the relationship between the height H with beam and the primary natural period T1 is shown in FIG. It finds as regression lines A and B like.

In the example of Figure 3,
In case of steel structure 1 (regression line A);
T1 = k ₁ · H (corresponding to the ● mark in FIG. 3) ... (1)
In the case of dead steel structure 1a (regression line B);
T1 = k ₂ · H (corresponding to the circle mark in FIG. 3) ... (2)
It has become.

Here, k ₁ and k ₂ are proportional coefficients, and as seen in FIG. 3, the variation with respect to the regression line A or B is small. That is, the larger the value of the beamed height H (the higher the voltage class), the longer the first-order natural period T1, and the relationship can be regarded as linear proportion.

  Next, using the various types of assumed seismic waves exemplified in Table 1, the time-based seismic response analysis of each of the representative steel structures is executed, and the maximum acceleration response value Ax1 and the short-term allowable stress of the column 2 (main column material and belly material) A relational expression with the degree ratio σ / f is obtained as a regression line.

  Figures 5 to 8 (the regression line C is a mark with a ● mark) are the graphs showing the relationship between the maximum acceleration response value Ax1 for the main column material and belly material of each voltage class and the short-term allowable stress ratio σ / f. Corresponding to the structure, the regression line D corresponds to the dead steel structure of the circle ○), the relationship can also be regarded as linear proportional.

  From the above, for the representative steel structure of each voltage class, the relational expression between the height H with beam and the first-order natural period T1 (Equation (1), Equation (2) above), maximum acceleration response value Ax1 and column 2 (main Since the relational expressions (regression straight lines C and D in Fig. 5 to Fig. 8) with the short-term allowable stress ratio σ / f of the column material and the belly material have been clarified, using these relational expressions, the short-term The allowable stress ratio σ / f can be estimated.

  The procedure is as follows.

(1) The primary natural period t1 of the target steel structure having a beam attachment height h is calculated from the equation (1) or (2).

(2) A maximum acceleration response value ax1 corresponding to the primary natural period t1 is predicted from an assumed acceleration response spectrum of seismic waves (for example, FIG. 4).

(3) The relationship between the maximum acceleration response value Ax1 for the main column material and the belly material of the column 2 of the representative steel structure of the voltage class to which the target steel structure belongs and the short-term allowable stress ratio σ / f (regression in FIGS. From the straight line C or D), the short-term allowable stress ratio σ / f corresponding to the obtained maximum acceleration response value ax1 is estimated.

  As described above, the short-term allowable stress ratio σ / f of the main column material and the abdominal material of the column 2 of the target steel structure is estimated, and the seismic margin is quantified, so the short-term allowable stress ratio σ / f If> 1, it is judged that the possibility of being damaged is high. The larger the value of the short-term allowable stress ratio σ / f, the higher the risk of damage, which is an important indicator in determining reinforcement priorities.

  As described above, according to the present invention, for the representative steel structure of each voltage class, the relational expression between the height H with beam and the primary natural period T1 and the maximum acceleration response value Ax1 and the pillar 2 (main pillars) in advance By using the approximation of the primary natural period t1 of the target steel structure to the primary natural period T1 of the representative steel structure by obtaining the relational expression between the short-term allowable stress ratio σ / f of the material and the belly material) The seismic capacity of the target steel structure can be determined extremely easily and quickly.

  Moreover, for many outdoor steel structures to be considered, it is extremely economical because the seismic measures can be prioritized without carrying out structural calculation and seismic response analysis.

  In the above description of the procedure, the estimation of the short-term allowable stress ratio σ / f is intended for both the main column material and the belly material. However, in the present invention, the earthquake resistance method is mainly intended to be simple. The short-term allowable stress ratio σ / f adopted in the sex evaluation can also be limited to the main column material of the lowermost node of the column 2. The reason is that it is thought that the damage of the main column supporting the own weight is likely to lead to the collapse of the outdoor steel structure rather than the damage of the belly.

  A series of work for the above-mentioned earthquake resistance evaluation of the target steel structure can be easily made by using a spreadsheet software and can be advanced.

  In addition, calculation charts as shown in FIG. 3 to FIG. 8 can be prepared in advance, and visual (analog) work can be performed on paper.

  Note that the charts related to the present invention are not limited to the embodiments shown in FIG. 3 to FIG. 8, and devising so that the relational expression displayed by the regression line becomes easy to use is earthquake resistance evaluation It is more effective in making work more efficient.

  The present invention is to be installed in substations at many points throughout the country in the future while large earthquakes are expected to occur, structural evaluation and seismic response analysis of seismic evaluation of many existing outdoor steel structures of different sizes and forms. It is a method that can be implemented efficiently and economically, and contributes to the promotion of prompt seismic strengthening of existing outdoor steel structures, which in turn contributes to the avoidance of power outages due to the occurrence of earthquakes.

1: Steel structure 1a: Retained steel structure 2: Column 3: Beam 4: Electric wire A, C: Regression straight line of steel structure B, D: Regression straight line of dead steel structure H: Beam attachment height of representative steel structure h: Target Steel beam attachment height
T1: Primary natural period of representative steel frame
t1: Primary natural period of the target steel structure
Ax1: Maximum acceleration response value of representative steel frame
ax1: Maximum acceleration response value of the target steel frame σ / f: Short-term allowable stress ratio

Claims (3)

In advance, the beam trims the height H of the representative iron structure obtained eigenvalue analysis or et al. For detailed model of representative Steel Structures set for each voltage class of outdoor steel structures and the relationship between the primary natural period T1, before Symbol and relationship between the primary natural period T1 and the maximum acceleration response values Ax1 of the respective representative iron structure obtained from the acceleration response spectra of the assumed seismic waves to detailed model of each representative steel structures, the detailed model of the representative steel Structures programmed and relationship between the short-term allowable stress intensity ratio sigma / f members of the maximum acceleration response value Ax1 the previous SL each representative steel structures obtained from a result of the stress analysis by the time history seismic response analysis was performed on Procedure stored in the storage means of the computer;
A step of inputting into the computer by the pre-Symbol input means the beam trims the height h of the subject steel structures is outdoor iron structure to be evaluated belongs to any one of the voltage class,
Substituting the beam attachment height h of the target steel structure input from the input means into the relational expression between the beam attachment height H of the representative steel structure stored in the storage means and the primary natural period T1, A procedure for calculating the primary natural period t1 by computing means of a computer ;
The target primary frame is predicted by substituting the calculated primary primary period t1 of the target frame for the relationship between the primary natural period T1 of each representative steel frame and the maximum acceleration response value Ax1 stored in the storage means a step of calculating the maximum acceleration response values ax1 by calculation means of the computer to be,
Substituting the calculated maximum acceleration response value ax1 for the target frame into the relational expression between the maximum acceleration response value Ax1 and the short-term allowable stress ratio σ / f of the members of each representative steel frame, the target A procedure for calculating the short-term allowable stress ratio σ / f estimated in the steel structure by computer calculation means;
A procedure of determining by means of a computer calculation means whether or not it is a seismic reinforcement target based on whether or not the calculated short-term allowable stress ratio σ / f in the target frame calculated is larger than 1 ;
Equipped with
By a series of the above procedures, the substation outdoor steel structures earthquake resistance simple evaluation method and evaluating earthquake resistance of outdoor steel structures to be the evaluation object in a simplified manner.
Here, the short-term allowable stress ratio σ / f of the member is the ratio of the stress degree σ acting on the member to the short-term allowable stress f of the member. In the earthquake resistance simple evaluation method of the substation outdoor steel structure according to claim 1, utilizing the fact that the beam attachment height H of the representative steel structure of each voltage class and the primary natural period T1 have a substantially linear proportional relationship, As a relational expression between the beam attachment height H of the representative steel structure and the primary natural period T1, a relational expression by a regression line is stored in the storage means, and only the primary attachment period h of the target steel structure is the primary natural period t1. The earthquake resistant simplified evaluation method for an outdoor steel structure of a substation characterized by estimating a short-term allowable stress ratio σ / f of the target steel structure to an assumed seismic wave by approximately obtaining   The earthquake resistance simple evaluation method of the substation outdoor steel structure of Claim 1 or 2 WHEREIN: The said outdoor steel structure is a truss structure comprised with the main pillar material and the belly material, It is not belly material but the lowest of the main pillar material Simple evaluation method of earthquake resistance of an outdoor steel structure of a substation characterized by evaluating only the short-term allowable stress ratio σ / f of the node.

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