Method for calculating floor operation counter-force of truck-mounted crane

Abstract

The invention provides a truck-mounted crane floor operation counter-force calculation method. The truck-mounted crane floor operation counter-force calculation method comprises the following steps that firstly, the acting force of each tire on a floor is calculated according to the dead weight of a truck-mounted crane; 2, calculating and obtaining the pressure N rounds of the tire on the floor; 3, the tire pressure P wheel of each tire during operation of the truck-mounted crane is obtained, the average tire pressure P flat is calculated, the tire pressure P wheel of each tire is divided by the average tire pressure P flat to obtain a coefficient f, and meanwhile, the pressure N wheel of each tire on the floor is multiplied by the corresponding coefficient f; 4, truck-mounted crane operation calculation is carried out, at the moment, pressure calculation on the floor is carried out only through the extending supporting legs, and N acting force of each supporting leg on the floor during operation is calculated; 5, constructing a ground system model, and calculating a floor load; and 6, simulating that the load condition of the floor is obtained when the truck-mounted crane enters the operation area and operates. According to the method, a theoretical safety basis is provided for hoisting construction through calculation.

Description

Technical Field

[0001] The invention relates to the technical field of hoisting construction, and in particular to a method for calculating reaction force of a vehicle hoisting floor operation. Background Art

[0002] A truck crane is a type of crane installed on an ordinary or special automobile chassis, with a driving cab and a lifting control cab separately installed. The advantages of this type of crane are good mobility and rapid transfer. The disadvantages are that it needs to be outriggered when working, cannot travel with load, and is not suitable for working on soft or muddy grounds. The chassis performance of a truck crane is equivalent to that of a truck with the same gross vehicle weight, and meets the technical requirements of road vehicles, so it can travel unimpeded on all types of roads. This type of crane is generally equipped with two control cabs for getting on and off, and the outriggers must be extended to maintain stability during operation.

[0003] When a truck crane is in operation, it is necessary to calculate the load of the construction area to ensure that the truck crane can reach the operation area and can perform lifting operations safely. Traditionally, the calculation is divided into two steps: one is to calculate the pressure on the opposite side of the truck crane's tires to ensure that the truck crane can enter the operation area, and the other is to calculate the pressure of the supporting legs on the ground when the truck crane is in operation. However, the calculation process ignores the impact of different tire pressures. Summary of the invention

[0004] In order to solve the above problems, the present invention discloses a method for calculating the reaction force of a vehicle crane floor operation, comprising the following steps:

[0005] Step 1: Calculate the force of each tire on the floor according to the deadweight of the truck crane. If there are multiple tires on one end of the same axis, the tires on the same end are regarded as a group;

[0006] Step 2: According to Appendix C of the Code for Loads on Building Structures, calculate and obtain the pressure N of the tire on the floor 轮 ;

[0007] Step 3: Obtain the tire pressure P of each tire during crane operation 轮 , and calculate the average tire pressure P 平 , the tire pressure of each tire P 轮 Divide by the average tire pressure P 平 Obtain the coefficient f and the pressure N of each tire on the floor 轮 Multiply by the corresponding coefficient f. The different tire pressures will cause the center of gravity of the truck crane to shift, resulting in different pressures for each tire. This can be corrected by setting the coefficient. The calculation formula is as follows:

[0008]

[0009] Step 4: Calculation of the mobile crane operation. At this time, only the extended support legs are used to calculate the pressure on the floor, and the force N exerted by each support leg on the floor during operation is calculated. 支 Generally, a truck crane is equipped with four supporting legs, which generate four forces during operation, and the calculation formula is as follows:

[0010]

[0011] Where G is the weight of the crane;

[0012] G1——Crane counterweight;

[0013] g——lifting weight;

[0014] r——the rotation radius of the hoisting weight;

[0015] R——counterweight turning radius;

[0016] L – distance between vertical outriggers in the direction of the crane;

[0017] h – distance between vertical outriggers in the direction perpendicular to the crane;

[0018] The coordinate system is formed according to the geometric center of gravity of the four supporting legs from a bird's-eye view, and each quadrant is an area. The tire coefficients in the area are added and averaged to obtain the parameter f1. The force N exerted by the supporting leg on the floor 支 Multiply by parameter f1 to obtain the final force on the floor;

[0019] Step 5: Construct the ground system model and calculate the floor load according to the Code for Design of Concrete Structures (GB50010-2010);

[0020] Step 6: Simulate the truck crane entering the operating area and during the operation to obtain the load conditions of the floor.

[0021] Preferably, in step 3, if the coefficients of the tires in the same group are calculated, the average value P of the tire group is calculated in advance. 组平 , then the average value P of the tire 组平 Divide by the average tire pressure P 平 Obtain the coefficient f.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. The present invention provides a theoretical safety guarantee for safe construction by calculating the load acting on the supporting surface (floor) when the truck crane reaches the working area and performs hoisting operations.

[0024] 2. The different tire pressures of truck cranes are introduced to solve the problem of center of gravity shift of truck cranes, thereby improving the accuracy of calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the tire position and force of a truck crane in an embodiment of the present invention;

[0026] Figure 2 It is a schematic top view of the operation of the truck crane in an embodiment of the present invention;

[0027] Figure 3 It is a schematic diagram of a floor model of the present invention. DETAILED DESCRIPTION

[0028] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0029] Here, when a 100t truck crane is selected for operation, its deadweight is 546kN, and the axle loads of axle 1 / 2 / 3 / 4 / 5 are 120kN, 120kN, 102kN, 102kN, 102kN, and 102kN respectively. The left and right wheelbases are 2.5m. The wheel pressure on one side is as follows: Figure 1 shown.

[0030] According to Appendix C of the Code for Loads on Building Structures, the effective span and length of the pressure load are the actual length and width plus the plate thickness. The plate thickness in the calculation area is 400mm. Therefore, the wheel pressure of each wheel is:

[0031] The first, second, third and fourth wheel pressures of the crane are N1, N2, N3, N4 and N5, and the local surface load of the floor wheel pressure is:

[0032] N1, N2=60 / (0.6×0.7)=142.9kN / m2;

[0033] N3, N4, N5=51 / (0.8×0.7)=91.1kN / m2.

[0034] Get the tire pressure P of each tire during crane operation 轮 , and calculate the average tire pressure P 平 , the tire pressure of each tire P 轮 Divide by the average tire pressure P 平 Obtain the coefficient f and the pressure N of each tire on the floor 轮Multiply by the corresponding coefficient f, the different tire pressures will cause the center of gravity of the crane to shift, resulting in different pressures for each tire, which can be corrected by setting the coefficient. In the theoretical task here, the tire pressure of each tire is consistent, so no correction is performed.

[0035] When the mobile crane is operating, the crane working load will be converted into a load group consisting of four concentrated loads acting on the floor. Figure 2 As shown, according to the construction plan, the crane legs should transfer the load to the concrete beam through the 2m*6 roadbed box. Therefore, the maximum leg load is applied to the crane station to verify whether the concrete beam meets the load requirements when the crane is in working condition.

[0036]

[0037] And G is the weight of the crane, which is 550kN;

[0038] G1——Crane counterweight, take 600kN;

[0039] g——Lifting weight, the maximum is 348N;

[0040] r——the rotation radius of the hoisting weight, which is taken as 12m;

[0041] R——counterweight turning radius, taken as 4.86m;

[0042] L - the distance between the vertical outriggers in the direction of the crane, which is 9m;

[0043] h – the distance between the vertical legs in the direction perpendicular to the crane, which is 8.3m;

[0044] When the boom is at a diagonal angle, i.e. α = 51°, the maximum pressure will be generated at fulcrum 2. At this time: N 支1 =371.4kN, N 支2 =477.3kN, N 支3 =271.7kN, N 支4 =375.6kN.

[0045] The maximum concentrated force load of the outrigger is 477.3KN. Considering the use of a 2m*6m roadbed box to transfer the load to the minimum cross-section of the structural beam (600*900) through the pad, the beam load area is: 0.6*2=1.2m; the local surface load on the beam is 477.3 / 2 / 1.2m=198.8KN / m 2 Consider using a 2m*6m roadbed box to transfer the load to a 1000*2000 structural beam through a pad. The load-bearing area of ​​the beam is: 1*2=2m2. The local surface load received by the beam is 477.3 / 2 / 2=119.3KN / m 2; Consider using a 2m*6m roadbed box to transfer force to a 1300*2000 structural beam through a pad, then the beam force area is: 1.3*2=2.6m 2 , then the local surface load received by the beam is 477.3 / 2 / 2.6=91.8KN / m 2 .

[0046] Build a floor model, the upper and lower reinforcement diameter of the floor is 16mm, and the spacing is 150mm. Calculate the span: Lx = 3250mm; Ly = 24000mm; plate thickness: h = 400mm; concrete grade: C40, such as Figure 3 As shown, the most unfavorable load loading position is determined using the influence line (surface) analysis function of MIDAS software.

[0047] The floor is calculated and the following parameters are obtained:

[0048] According to Article 6.2.14 of the Code for Design of Concrete Structures (GB50010-2010), the bending bearing capacity is: after calculation, the floor slab can withstand a maximum bending moment of 154.9 kN*m, and the calculated maximum bending moment is 63.71 kN*m < 154.9 kN*m, so the floor slab meets the bending requirements;

[0049] According to Article 6.5.1 of the Code for Design of Concrete Structures (GB50010-2010), the shear capacity of the slab is: According to the simulation calculation results, the maximum shear force of the slab is 93.45KN<650.7kN, which meets the requirements;

[0050] According to Article 7.1.4 of the Code for Design of Concrete Structures (GB50010-2010), the stress of steel bars is: 198.8MPa;

[0051] According to Article 7.1.2 of the "Code for Design of Concrete Structures" (GB50010-2010), the maximum crack width is: Maximum crack width: 0.251<[ωmax]=0.3mm, which meets the requirements.

[0052] From the above calculation results, it can be seen that when the 160t truck crane travels on the elevated floor, the floor slab's bending strength and cracks and other indicators meet the specifications and design requirements, and no reinforcement is required.

[0053] When lifting with a 160t truck crane, the maximum reaction force of the outrigger is: N 支1 =371.4kN, N 支2 =477.3kN, N 支3 =271.7kN, N 支4=375.6kN. The maximum concentrated load of the outrigger is 477.3KN. Considering the use of a 2m*6m roadbed box to transfer the load to the minimum cross-section of the structural beam (600*900) through pads, the local surface load on the beam is 198.8KN / m 2 ; The local surface load of the structural beam 1000*2000 is 119.3KN / m 2 ; The local surface load of the structural beam 1300*2000 is 91.8KN / m 2 .

[0054] According to the above information, the outrigger load is relatively large when the 160-ton truck crane is hoisting. The lower concrete structure of the 160-ton truck crane can be verified according to the "Concrete Code", which will not be repeated here. It can then be determined whether the surface meets the operational needs of the 160t truck crane, thereby providing a theoretical guarantee for safe construction.

[0055] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above technical features.

Claims

1. A method for calculating the reaction force of a car crane floor operation, characterized in that: The following steps are involved: Step 1: Calculate the force of each tire on the floor according to the deadweight of the truck crane. If there are multiple tires on one end of the same axis, the tires on the same end are regarded as a group; Step 2: According to Appendix C of the Code for Loads on Building Structures, calculate and obtain the pressure N of the tire on the floor 轮 ; Step 3: Obtain the tire pressure P of each tire during crane operation 轮 , and calculate the average tire pressure P 平 , the tire pressure of each tire P 轮 Divide by the average tire pressure P 平 Obtain the coefficient f and the pressure N of each tire on the floor 轮 Multiply by the corresponding coefficient f; Step 4: Calculation of the mobile crane operation. At this time, only the extended support legs are used to calculate the pressure on the floor, and the force N exerted by each support leg on the floor during operation is calculated. 支 The coordinate system is formed according to the geometric center of gravity of the four supporting legs from top view, and each quadrant is an area. The tire coefficients in the area are added and averaged to obtain the parameter f1. The force N exerted by the supporting leg on the floor 支 Multiply by parameter f1 to obtain the final force on the floor; Step 5: Construct the ground system model and calculate the floor load according to the Code for Design of Concrete Structures (GB50010-2010); Step 6: Simulate the truck crane entering the operating area and during the operation to obtain the load conditions of the floor.

2. A method for calculating the reaction force of a vehicle crane floor operation according to claim 1, characterized in that: In step 3, if the coefficients of the same group of tires are calculated, the average value P of the group of tires is calculated in advance. 组平 , then the average value P of the tire 组平 Divide by the average tire pressure P 平 Obtain the coefficient f.

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