A Random Walk Pedestrian Comfort Analysis Method Based on a Preset Path

Abstract

The present invention discloses a method for analyzing the comfort of pedestrians walking randomly based on a preset path, belonging to the technical field of digitalization of civil engineering, including S1, constructing the walking path of pedestrians; S2, distributing pedestrians on the walking path according to the crowd density, and determining the magnitude of the pedestrian load generated when each pedestrian lands at each moment; S3, transferring the pedestrian load generated by pedestrians on the walking path to the grid nodes of the structure; The method for analyzing the comfort of pedestrians walking randomly based on a preset path provided by the present invention realizes that the size division of the structural grid no longer needs to depend on the walking step length of pedestrians, and realizes the randomness of the walking step length of pedestrians at each moment and the randomness of the magnitude of the applied pedestrian load.

Description

Technical Field

[0001] The present invention relates to the technical field of civil engineering digitalization, and in particular to a method for analyzing the comfort of pedestrians walking randomly based on a preset path. Background Art

[0002] In recent years, with the wide application of long-span and lightweight bridge structures in civil engineering, the problem of structural vibration comfort has been increasingly emphasized. The simulation of pedestrians walking on the bridge deck and the simulation of pedestrian loads are the key links in the analysis of structural vibration comfort.

[0003] In traditional pedestrian comfort analysis methods, the walking parameters of people on the bridge are the same, and each person takes steps in place at the same acting point. Or after establishing a walking pedestrian model, the walking step lengths of pedestrians are the same, and random walking cannot be achieved. The above two analysis methods are quite different from the actual walking situation of pedestrians on the bridge.

[0004] When performing pedestrian comfort analysis in finite element software, in order to ensure the true simulation of the dynamic response of the bridge (such as frequency, acceleration), it is necessary to mesh the bridge deck. In traditional pedestrian comfort analysis methods, in order to ensure that pedestrian loads can be accurately transmitted to the bridge deck, and the landing points of pedestrians represent the application points of pedestrian loads, so the mesh size of the structure must be divided according to the walking step lengths of pedestrians, and there are the following two problems:

[0005] (1) Under the current trend of the development of bridge structures towards long spans, the number of walking steps of pedestrians is large, the mesh division is too dense, and the calculation amount is greatly increased, resulting in a significant reduction in the calculation efficiency of the software;

[0006] (2) When encountering a bridge deck structure with an irregular shape, it is difficult to perform dense mesh division. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for analyzing the comfort of pedestrians walking randomly based on a preset path to solve the problems existing in the above background art.

[0008] To achieve the above purpose, the present invention provides a method for analyzing the comfort of pedestrians walking randomly based on a preset path, including the following steps:

[0009] S1. Construct the walking path of pedestrians;

[0010] S2. Distribute pedestrians on the walking path according to the crowd density, and determine the magnitude of the pedestrian load generated when each pedestrian lands at each moment;

[0011] S3. Transmit the pedestrian loads generated by pedestrians on the walking path to the grid nodes of the structure.

[0012] Preferably, the determination method of the walking path in step S1 is as follows:

[0013] S11. Draw a walking path on the bridge deck. The walking path forms certain intersections with the grid of the bridge deck, and these intersections are the nodes on the walking path.

[0014] S12. Denote the distance from the th node on the walking path to the starting point of the walking path as , and establish an ordered distance list , represents the position of the starting point, stores the distances from each node on the walking path to the starting point, and satisfies ascending order. Then this ordered distance list stores the node information of the walking path.

[0015] S13. Determine multiple walking paths simultaneously through steps S11 - S12.

[0016] Preferably, in step S11, directly specify some nodes of the structural grid as the nodes of a walking path.

[0017] Preferably, step S2 specifically includes:

[0018] S21. Uniformly distribute pedestrians on the walking path at the initial moment according to the crowd density as the starting points of each pedestrian.

[0019] S22. Introduce the mean step frequency and the root mean square of step frequency . Consider the step frequency of pedestrians as obeying a normal distribution.

[0020] S23. Introduce the walking step length and the walking step frequency into each pedestrian, and obtain the walking speed of each pedestrian according to .

[0021] S24. Determine the landing points of each pedestrian on the walking path at each moment according to the walking speed, and set that when a pedestrian walks to the end of the bridge, a new pedestrian will start walking from the beginning of the bridge to the end of the bridge to ensure that the crowd density on the bridge deck remains unchanged and achieve the effect of stable crowd flow on the bridge deck.

[0022] S25. Introduce the single - person weight into each pedestrian, and determine the magnitude of the pedestrian load generated when each pedestrian lands at each moment.

[0023] Preferably, the calculation formula in step S25 is:

[0024] ;

[0025] Among them, is the pedestrian weight; is the first-order load frequency; is the time; is the dynamic factor corresponding to the -th order load frequency, and .

[0026] Preferably, step S3 specifically includes:

[0027] S31. Denote the distance from the position of the pedestrian at time on the walking path (i.e., the position of the pedestrian load application point) to the starting point of the walking path as ;

[0028] S32. Through binary search, substitute into the ordered distance list to find the two adjacent structural grid nodes and nearest to the pedestrian load application point;

[0029] S33. Distribute the pedestrian load to the two adjacent grid nodes.

[0030] Preferably, step S33 is implemented by the following formula:

[0031] ;

[0032] Among them, is the pedestrian load applied by the pedestrian at time ; is the load distributed to the structural grid node ; is the load distributed to the structural grid node ; is the distance from the pedestrian load application point to the starting point of the walking path; is the distance from the node to the starting point of the walking path; is the distance from the node to the starting point of the walking path.

[0033] Therefore, by adopting the above-mentioned method for analyzing pedestrian comfort based on a preset path, the present invention has the following beneficial effects:

[0034] (1) The constructed walking path can truly simulate the walking situation of pedestrians on the bridge deck, and is more in line with the walking state of pedestrians on the actual bridge compared with the existing methods;

[0035] (2) By introducing the mean step frequency and the root mean square of step frequency, and considering the pedestrian step frequency as obeying a normal distribution, etc., the randomness of the walking step length of pedestrians at each moment and the randomness of the applied pedestrian load size are realized.

[0036] (3) When transferring the pedestrian load to the structural grid nodes, the method of using binary search to find the two adjacent structural grid nodes closest to the pedestrian load application point and distributing the load is adopted. This method does not require the pedestrian load application point to be necessarily on the structural grid nodes, thus avoiding the problems of excessive calculation amount, reduced calculation efficiency caused by dividing the grid according to the pedestrian walking step length in the traditional method, and the difficulty of dense grid division in irregular bridge deck structures, improving the calculation efficiency and reducing the grid division difficulty.

[0037] (4) It can more accurately determine the magnitude of the pedestrian load generated when each pedestrian lands at each moment, thereby providing a more accurate pedestrian load simulation for the structural vibration comfort analysis and improving the accuracy of the analysis results.

[0038] The following will further describe the technical solution of the present invention in detail through the drawings and embodiments. Description of the Drawings

[0039] Figure 1 It is a flowchart of a method for analyzing pedestrian comfort with random walking based on a preset path according to the present invention.

[0040] Figure 2 It is a schematic diagram of the walking path in the embodiment of the present invention. Specific Embodiments

[0041] The following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0042] Please refer to Figure 1 , a method for analyzing pedestrian comfort with random walking based on a preset path, including the following steps:

[0043] S1. Construct the walking path of pedestrians. As Figure 2 shown, the determination method is:

[0044] S11. Draw a walking path on the bridge deck. The walking path forms certain intersections with the grid of the bridge deck, and these intersections are the nodes on the walking path; or directly specify some nodes of the structural grid as the nodes of a walking path.

[0045] S12. For the The distance from a node to the starting point of the walking path is denoted as and an ordered distance list is established , representing the position of the starting point, storing the distances from each node of the walking path to the starting point, and satisfying the ascending order. Then, this ordered distance list stores the node information of the walking path;

[0046] S13. By steps S11 - S12, multiple walking paths can be determined simultaneously.

[0047] S2. Distribute pedestrians on the walking path according to the crowd density, and determine the magnitude of the pedestrian load generated when each pedestrian lands at each moment, thus solving the problem that the existing pedestrian comfort analysis method cannot achieve random walking of pedestrians. Specifically, it includes:

[0048] S21. Uniformly distribute pedestrians on the walking path at the initial moment according to the crowd density as the starting point of each pedestrian;

[0049] S22. Introduce the mean step frequency and the root mean square of step frequency , and regard the step frequency of pedestrians as obeying a normal distribution;

[0050] S23. Introduce the walking step length and the walking step frequency into each pedestrian, and obtain the walking speed of each pedestrian according to ;

[0051] S24. Determine the landing point of each pedestrian on the walking path at each moment according to the walking speed, and set that when a pedestrian walks to the end of the bridge, a new pedestrian will start walking from the beginning of the bridge to the end of the bridge to ensure that the crowd density on the bridge deck remains unchanged and achieve the effect of stable crowd flow on the bridge deck;

[0052] S25. Introduce the single - person weight into each pedestrian, and determine the magnitude of the pedestrian load generated when each pedestrian lands at each moment. The calculation formula is:

[0053] ;

[0054] where, is the pedestrian weight; is the first - order load frequency; is the time; is the dynamic factor corresponding to the th - order load frequency, .

[0055] Through the above, the randomness of the walking step length of pedestrians at each moment and the randomness of the applied pedestrian load are realized.

[0056] S3. Transfer the pedestrian load generated by pedestrians on the walking path to the grid nodes of the structure, specifically including:

[0057] S31. Denote the distance from the position of the pedestrian on the walking path at a certain moment (i.e., the position of the pedestrian load application point) to the starting point of the walking path as ; ;

[0058] S32. Through binary search, substitute into the ordered distance list to find two adjacent structural grid nodes to the pedestrian load application point and ;

[0059] S33. Allocate the pedestrian load to the two adjacent grid nodes, which is specifically realized by the following formula:

[0060] ;

[0061] Where, is the pedestrian load applied by the pedestrian at moment; is the load allocated to the structural grid node ; is the load allocated to the structural grid node ; is the distance from the pedestrian load application point to the starting point of the walking path; is the distance from the node to the starting point of the walking path; is the distance from the node to the starting point of the walking path. Through the above, it is realized that the size division of the structural grid no longer needs to depend on the walking step length of pedestrians.

[0062] Therefore, by adopting the above-mentioned random walking pedestrian comfort analysis method based on a preset path, the present invention realizes that the size division of the structural grid no longer needs to depend on the walking step length of pedestrians, and realizes the randomness of the walking step length of pedestrians at each moment and the randomness of the applied pedestrian load size.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for analyzing the comfort of pedestrians in random walking based on a preset path, characterized in that, It includes the following steps: S1. Construct the walking path of pedestrians; S2. Distribute pedestrians on the walking path according to the crowd density, and determine the magnitude of the pedestrian load generated when each pedestrian lands at each moment; S3. Transfer the pedestrian load generated by pedestrians on the walking path to the grid nodes of the structure; The determination method of the walking path in step S1 is as follows: S11. Draw a walking path on the bridge deck. The walking path forms certain intersections with the grid of the bridge deck, and these intersections are the nodes on the walking path; S12. Denote the distance from the th node on the walking path to the starting point of the walking path as , and establish an ordered distance list , which stores the distances from each node of the walking path to the starting point and satisfies ascending order. Then this ordered distance list stores the node information of the walking path; S13. Determine multiple walking paths simultaneously through steps S11 - S12; Step S2 specifically includes: S21. Uniformly distribute pedestrians on the walking path at the initial moment according to the crowd density as the starting points of each pedestrian; S22. Introduce the average step frequency and the root mean square of the step frequency , and regard the step frequency of the pedestrian as subject to a normal distribution; S23. Introduce the walking step length and the walking step frequency into each pedestrian, and obtain the walking speed of each pedestrian according to ; S24. Determine the landing points of each pedestrian on the walking path at each moment according to the walking speed, and set that when a pedestrian walks to the end of the bridge, a new pedestrian will start walking from the beginning of the bridge to the end of the bridge at the beginning of the bridge to ensure that the crowd density on the bridge deck remains unchanged and achieve the effect of stable crowd flow on the bridge deck; S25. Introduce the single-person weight into each pedestrian, and determine the magnitude of the pedestrian load generated when each pedestrian lands at each moment; Step S3 specifically includes: S31. Denote the distance from the position of the pedestrian at a moment on the walking path to the starting point of the walking path as ; ​ S32. By means of binary search, is substituted into the ordered distance list to find the two adjacent structural grid nodes closest to the point of application of the pedestrian load and ; S33. Distribute the pedestrian load to two adjacent grid nodes.

2. The random walking pedestrian comfort analysis method based on a preset path according to claim 1, wherein: Certain nodes of the structure grid are designated as the nodes of a walking path through step S11 or directly.

3. A random walking pedestrian comfort analysis method based on a preset path according to claim 1, characterized in that, The calculation formula of step S25 is: ； Among them, is the pedestrian weight; is the first-order pedestrian load frequency; is the time; is the dynamic factor corresponding to the nth-order load frequency, and , .

4. A method for analyzing the comfort of pedestrians in random walking based on a preset path according to claim 1, characterized in that, Step S33 is implemented through the following formula: ； Among them, is the pedestrian load applied by pedestrians at moment; is the load assigned to the structural grid node ; is the load assigned to the structural grid node ; is the distance from the pedestrian load application point to the starting point of the walking path; is the distance from the node to the starting point of the walking path; is the distance from the node to the starting point of the walking path.

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