Concrete structure prestress equivalent simulation method

A concrete structure, equivalent simulation technology, applied in the field of effective simulation, can solve problems such as the inability of finite element analysis of complex structures, and achieve the effect of efficient calculation methods and accurate calculation results

Pending Publication Date: 2019-04-23

POWERCHINA CHENGDU ENG

12 Cites 2 Cited by

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Problems solved by technology

[0004] In order to overcome the shortcomings of the existing "equivalent load method" that cannot perform finite element analysis on complex structures, the technical problem to...

Method used

In sum, under two kinds of calculation methods, the stress in the test beam and the displacement distribution rule are basically the same, and the position that the maximum value occurs is the same, and the percentage difference of numerical value is no more than 5%, and it shows that two kinds of methods are not more than 5% in the prestressed concrete beam. The effect and accuracy of the prestress equivalent simulation are basically the same. Since the equivalent simulation of the prestress in simple prestressed concrete structures with the "eq...

Abstract

The invention discloses a prestress equivalent simulation method in finite element analysis of a complex prestressed concrete structure in the field of water conservancy and hydropower engineering. The prestress equivalent simulation method comprises the following steps of establishing a concrete structure unit according to structure arrangement and size; establishing pre-stressed tendon units according to the specifications and sizes of pre-stressed tendons configured in the concrete structure; applying the cooling value to the prestressed tendon unit, so that the shrinkage force generated byshrinkage of the prestressed tendon is used for simulating the pre-pressing stress of the prestressed tendon on the concrete. The beneficial effects of the invention are as follows the prestressed tendons and concrete units are established respectively; only the prestressing force of the prestressed tendons, the cross-section area, the linear dilatation coefficient and the elasticity modulus needto be clear, so that the actual effect of the prestressed tendons is considered, the prestressed effect can be effectively simulated, only the cooling value of the prestressed tendons needs to be calculated in a complex prestressed concrete structure, the calculation result is accurate, and the calculation method is efficient.

Application Domain

Design optimisation/simulationSpecial data processing applications

Technology Topic

Elastic modulusHydropower engineering +8

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Examples

Experimental program(1)

Example Embodiment

[0028] Examples:

[0029] Such as figure 1 , The section form is a T-shaped section commonly used in bridge engineering, the concrete strength grade is C40, the non-prestressed ordinary rebar adopts 4 φ12 grade II steel bars, and the prestressed tendons are 7 φ5 high-strength steel wires. The tension control prestress value is The pre-stressed tendons are 75% of the standard strength value. The high-strength steel wire has a standard strength of 1600 MPa. The pre-stressed tendons are arranged in an arc shape with a radius of 16m.

[0030] figure 2 It is a grid diagram of concrete and prestressed tendon models established based on the above dimensions.

[0031] According to the "cooling method" formula of the present invention, the cooling value to be applied to the prestressed tendons is 425°C. The external load of the test beam is applied in stages at three points, in order of 6, 10, 20, 26, 33, 40kN. The above load and gravity are applied to the test beam for nonlinear calculation.

[0032] Such as Figure 3 ~ Figure 6 Under the two calculation methods, there is basically no difference between the stress and displacement laws of prestress acting alone and all loads acting. Under the action of single prestress, the maximum axial tensile stress and compressive stress of the test beam calculated by the "equivalent load method" are 2.69MPa and -10.82MPa (see image 3 ), and the corresponding stress calculated by the "cooling method" is 2.71MPa and -10.56MPa (see Figure 4 ); Under all loads, the maximum axial tensile stress and compressive stress of the test beam calculated by the "equivalent load method" are 2.86 MPa and -20.66 MPa (see Figure 5 ), and the corresponding stress calculated by the "cooling method" is 2.96MPa and -20.01MPa (see Image 6 ). From the stress point of view, the positions of the maximum axial tensile stress and compressive stress of the test beam under the two calculation methods are the same, and the magnitude of the numerical value is basically unchanged. In terms of displacement, under the two calculation methods, the displacement distribution law and the maximum displacement of the test beam are almost unchanged when the prestress alone and all loads are applied, and the position of the maximum displacement is also the same.

[0033] In order to demonstrate in more detail the feasibility of the new method of prestress equivalent simulation in the finite element analysis of the prestressed concrete structure provided by the present invention, the axial stress of the neutral section of the prestressed concrete beam in the two methods is compared in a table. , See Table 1. Under the two calculation methods, the changing trends of the axial stress at the top and bottom of the neutral section of the test beam under each load step basically coincide, and the difference in the magnitude of the stress value does not exceed 5%. The two methods have an effect on the prestressed concrete beam. The effect and accuracy of the equivalent simulation of prestressing action are basically the same.

[0034] Table 1 Axial stress at mid-span of neutral section of prestressed concrete beam (MPa)

[0035]

[0036] In summary, under the two calculation methods, the distribution of stress and displacement in the test beam is basically the same, the maximum value appears at the same location, and the difference in value does not exceed 5%, indicating that the two methods have an effect on the prestress in the prestressed concrete beam. The effect and accuracy of the simulation are basically the same. Since using the "equivalent load method" to simulate the prestress in a simple prestressed concrete structure is a method that has been recognized in research and engineering practice, and its accuracy is high, the "cooling method" is used to simulate the prestress Equivalent simulation of stress is feasible and its accuracy is basically the same as the "equivalent load method". It shows that the results of the present invention can accurately and efficiently simulate the prestress in the finite element analysis of a complex prestressed concrete structure, and at the same time have sufficient reliability.

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The calculation result is accurate

Concrete structure prestress equivalent simulation method

A concrete structure, equivalent simulation technology, applied in the field of effective simulation, can solve problems such as the inability of finite element analysis of complex structures, and achieve the effect of efficient calculation methods and accurate calculation results

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

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Examples

Example Embodiment

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Description & Claims & Application Information

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