A damage assessment method for ship impact with reinforced concrete structure

Abstract

A damage assessment method for a ship impacting a reinforced concrete structure. The method includes the following steps: obtaining residual displacements detected on-site for the damaged reinforced concrete structure; a finite element numerical model; obtaining a maximum impact force-impact duration curve; calculating numerical simulation residual displacements of the damaged reinforced concrete structure; comparing the degree of fit; and extracting damage indexes of hidden parts of the damaged reinforced concrete structure. The present invention uses a simplified ship impact force-time curve to input into a finite element program to simulate the dynamic response of a ship impacting a reinforced concrete structure, which has high computational efficiency and low computational cost. The correctness of the numerical calculation is ensured by comparing and verifying with the residual displacements detected on-site. Based on the correct numerical model, quantitative damage values ​​are obtained, and the damage state of the damaged reinforced concrete structure can be accurately assessed. Therefore, the damage state of the damaged reinforced concrete structure can be efficiently and accurately assessed, providing a basis for the repair, reinforcement and safe use of the structure.

Description

Technical Field

[0001] The invention belongs to the technical field of civil engineering and hydraulic engineering, and in particular relates to a damage assessment method for a ship colliding with a reinforced concrete structure. Background Art

[0002] In the field of civil engineering and hydraulic engineering, accidents where ships accidentally collide with reinforced concrete structures such as docks or bridges due to operational errors or adverse environmental influences such as storm surges occur frequently. Ship collisions can cause damage to reinforced concrete structures, which directly affects the safety of these structures in the later use. Therefore, damage assessment of damaged reinforced concrete structures has become an important means of evaluating their safety. Existing methods usually conduct on-site inspections of damaged reinforced concrete structures and use inspection data to evaluate their damage status. However, since part of the structure of hydraulic structures is in the water or soil, it is difficult to detect and evaluate the damage status of its hidden parts through on-site inspections. Therefore, it is difficult to scientifically and reasonably evaluate the damage of reinforced concrete structures through inspection methods. Using numerical analysis methods to simulate the structural collision process and evaluate the damage status of the damaged structure is a feasible means, but the numerical simulation of the real restoration of the damaged reinforced concrete structure is difficult to achieve and has high computational cost, which is often not suitable for engineering applications. Therefore, establishing a numerical simulation method that can efficiently analyze the damage of damaged reinforced concrete structures, truly evaluate the damage status of damaged reinforced concrete structures, and grasp the damaged weak parts of damaged reinforced concrete structures can provide important reference opinions for the later maintenance, reinforcement and safe use of reinforced concrete structures. However, there is currently a lack of effective methods. Summary of the invention

[0003] In order to solve the above problems, the purpose of the present invention is to provide a damage assessment method for a ship impacting a reinforced concrete structure. The method is based on on-site detection data, accurately simulates the dynamic response process of the damaged reinforced concrete structure, grasps the damage state of the structure in hidden parts, and has controllable calculation costs and is easy to apply in actual engineering.

[0004] In order to achieve the above object, the damage assessment method of a ship impacting a reinforced concrete structure provided by the present invention comprises the following steps performed in sequence:

[0005] Step 1: Conduct on-site inspection of the damaged reinforced concrete structure to obtain the on-site inspection residual displacement of the damaged reinforced concrete structure;

[0006] Step 2: Establish a finite element numerical model of the reinforced concrete structure according to the size and material of the reinforced concrete structure;

[0007] Step 3: Obtain the maximum impact force-impact duration curve according to the ship mass and ship speed;

[0008] Step 4: Input the maximum impact force-impact duration obtained in step 3 into the finite element numerical model established in step 2 to calculate the numerical simulation residual displacement of the damaged reinforced concrete structure;

[0009] Step 5: Compare the numerical simulation residual displacement calculated in step 4 with the on-site detection residual displacement obtained in step 1. If the agreement is poor, change the above maximum impact force-impact duration curve, and then input it into the finite element numerical model to calculate the numerical simulation residual displacement of the damaged reinforced concrete structure again. Then compare the numerical simulation residual displacement with the on-site detection residual displacement, and repeat this process until a good agreement is achieved. Stop the calculation and obtain the final maximum impact force-impact duration curve.

[0010] Step 6: Input the above-mentioned final maximum impact force-impact duration curve into the finite element numerical model for calculation, and extract the damage index of the hidden parts of the damaged reinforced concrete structure to evaluate the damage state of the damaged reinforced concrete structure.

[0011] In step 1, the residual displacement detected on site is the displacement coordinate value of the damaged reinforced concrete structure minus the displacement coordinate value of the reinforced concrete structure when no collision occurs.

[0012] In step 2, the method for establishing a finite element numerical model of a reinforced concrete structure is: using the entity units of large-scale general finite element software including ANSYS and ABAQUS to establish a concrete model of components including piles and beams in the reinforced concrete structure, and using beam units to establish a steel bar model, wherein the concrete and steel bar materials are respectively given a damage constitutive relationship for the concrete and an elastic-plastic constitutive relationship for the steel.

[0013] In step 3, the ship mass is the ship tonnage, the ship speed is the speed recorded by the speed meter on the ship at the time of collision, the impact force at the initial moment of the ship collision is assumed to be the maximum impact force, the impact force at the end moment of the ship collision is assumed to be 0, and the impact force is linearly related to time, then the relationship between the maximum impact force and the collision duration is as follows:

[0014]

[0015] Where: P is the maximum impact force; M is the mass of the ship; V is the ship speed at the initial moment of the ship impact; T is the duration of the impact.

[0016] In step 4, the finite element numerical model calculation uses a display algorithm to extract the displacement of the damaged reinforced concrete structure after the ship collision and the displacement of the reinforced concrete structure before the ship collision from the finite element numerical model, and the difference between the two is used to obtain the numerical simulation residual displacement of the damaged reinforced concrete structure.

[0017] In step five, when comparing the numerical simulation residual displacement calculated in step four with the on-site detection residual displacement obtained in step one, if the difference is within ±5%, it is considered to be in good agreement; otherwise, if the agreement is not good, the impact duration T in step three is changed, the maximum impact force P is recalculated, a new maximum impact force-impact duration curve is obtained, and the curve is input into the finite element numerical model for calculation.

[0018] The advantages and positive effects of the present invention are as follows: a simplified ship collision force-time curve is input into a finite element program to simulate the dynamic response of a ship colliding with a reinforced concrete structure, which has high calculation efficiency and low calculation cost compared with the traditional method of simulating the ship collision structure process using a ship model; the correctness of the numerical calculation is guaranteed by comparing and verifying with the residual displacement detected on site; based on the correct numerical model, quantitative damage values ​​are obtained, and the damage state of the damaged reinforced concrete structure can be accurately evaluated; therefore, the method of the present invention can efficiently and accurately evaluate the damage state of the damaged reinforced concrete structure, providing a basis for the maintenance, reinforcement and safe use of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 (a) and (b) are respectively a front view and a top view of a reinforced concrete pile cap used in an embodiment of the present invention;

[0020] Figure 2 This is a displacement-time curve calculated using the method of the present invention. DETAILED DESCRIPTION

[0021] In order to further understand the content, features and effects of the present invention, the following embodiments are given as examples and described in detail with reference to the accompanying drawings:

[0022] The damage assessment method for a ship colliding with a reinforced concrete structure provided by the present invention comprises the following steps performed in sequence:

[0023] Step 1: Conduct on-site inspection of the damaged reinforced concrete structure to obtain the on-site inspection residual displacement of the damaged reinforced concrete structure;

[0024] The residual displacement detected on site is the displacement coordinate value of the damaged reinforced concrete structure minus the displacement coordinate value of the reinforced concrete structure when no collision occurs.

[0025] Step 2: Establish a finite element numerical model of the reinforced concrete structure according to the size and material of the reinforced concrete structure;

[0026] The method for establishing a finite element numerical model of a reinforced concrete structure is: using entity units of large-scale general finite element software including ANSYS and ABAQUS to establish a concrete model of components including piles and beams in the reinforced concrete structure, and using beam units to establish a steel bar model, wherein the concrete and steel bar materials are respectively given a damage constitutive relationship for the concrete and an elastic-plastic constitutive relationship for the steel.

[0027] Step 3: Obtain the maximum impact force-impact duration curve according to the ship mass and ship speed;

[0028] The ship mass is the ship tonnage, the ship speed is the speed recorded by the speed meter on the ship at the time of collision, the impact force at the initial moment of the ship collision is the maximum impact force, the impact force at the end of the ship collision is 0, and the impact force is linearly related to time, then the relationship between the maximum impact force and the collision duration is as follows:

[0029]

[0030] Where: P is the maximum impact force; M is the mass of the ship; V is the ship speed at the initial moment of the ship impact; T is the duration of the impact.

[0031] Step 4: Input the maximum impact force-impact duration obtained in step 3 into the finite element numerical model established in step 2 to calculate the numerical simulation residual displacement of the damaged reinforced concrete structure;

[0032] The finite element numerical model calculation uses a display algorithm to extract the displacement of the damaged reinforced concrete structure after the ship collision and the displacement of the reinforced concrete structure before the ship collision from the finite element numerical model, and the difference between the two is used to obtain the numerical simulation residual displacement of the damaged reinforced concrete structure.

[0033] Step 5: Compare the numerical simulation residual displacement calculated in step 4 with the on-site detection residual displacement obtained in step 1. If the agreement is poor, change the above maximum impact force-impact duration curve, and then input it into the finite element numerical model to calculate the numerical simulation residual displacement of the damaged reinforced concrete structure again. Then compare the numerical simulation residual displacement with the on-site detection residual displacement, and repeat this process until a good agreement is achieved. Stop the calculation and obtain the final maximum impact force-impact duration curve.

[0034] When comparing the numerical simulation residual displacement calculated in step 4 with the on-site detection residual displacement obtained in step 1, if the difference is within ±5%, it is considered to be in good agreement; otherwise, the agreement is not good, then the impact duration T in step 3 is changed, the maximum impact force P is recalculated, a new maximum impact force-impact duration curve is obtained, and the curve is input into the finite element numerical model for calculation.

[0035] Step 6: Input the above-mentioned final maximum impact force-impact duration curve into the finite element numerical model for calculation, and extract the damage index of the hidden parts of the damaged reinforced concrete structure to evaluate the damage state of the damaged reinforced concrete structure.

[0036] The present invention is based on on-site detection data, compares and verifies the numerical simulation results with the on-site measured results, and extracts the damage index of the hidden parts of the damaged reinforced concrete structure from the final finite element numerical model, which is used to evaluate the damage state of the structure, so as to ensure that the damage assessment of the damaged reinforced concrete structure is accurate and efficient.

[0037] The advantages of the method of the present invention are illustrated below by an application example.

[0038] In this embodiment, the tonnage of the ship is 66,000 tons. The ship speed recorded by the speed meter on the ship before the ship collision is 0.86 m / s. The on-site detection residual displacement of the damaged reinforced concrete structure is 657 mm.

[0039] See also Figure 1 In this embodiment, the cross-sectional dimensions of the cap in the reinforced concrete pile cap structure are 12×12×2.5m, that is, the length B is 12m, the height H is 2.5m, the diameter of the reinforced concrete cast-in-place pile is 2.6m, the length L from the pile top to the bedrock is 37m, the concrete is C30, the steel bar is HRB400, and the steel bar volume reinforcement ratio is 0.98%.

[0040] In this embodiment, the present invention uses ANASYS to establish a finite element numerical model of a reinforced concrete pile cap structure. The concrete of the cap and the pile are modeled using solid units, and the concrete is given a damage constitutive relationship. The steel bars are modeled using beam units and are given an elastic-plastic constitutive relationship.

[0041] See also Figure 2 The method of the present invention is used to calculate the structural dynamic response of the maximum impact force-impact duration curve corresponding to the maximum impact forces of 7.568MN, 8.732MN, 8.109MN, 8.409MN and 8.256MN when the impact durations T=13.0s, 13.5s, 13.75s, 14.0s and 15.0s. It can be seen from the displacement-time curve in the figure that when the impact duration T=13.75s, the numerical simulation residual displacement is 641mm, compared with the on-site detection residual displacement of 657mm, the error is 2.4%, which meets the accuracy requirement.

[0042] The damage index of most protective layer concrete of reinforced concrete piles numerically simulated by the present invention reaches 1.0, which is severe damage, and the damage index of a small number of core area concrete is about 0.4, indicating that the core area concrete has not been severely damaged.

[0043] Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can make many forms without departing from the scope of protection of the present invention and the claims, all of which fall within the scope of protection of the present invention.

Claims

1. A damage assessment method for a ship impacting a reinforced concrete structure, characterized in that: The damage assessment method for a ship impacting a reinforced concrete structure comprises the following steps performed in sequence: Step 1: Conduct on-site inspection of the damaged reinforced concrete structure to obtain the on-site inspection residual displacement of the damaged reinforced concrete structure; Step 2: Establish a finite element numerical model of the reinforced concrete structure according to the size and material of the reinforced concrete structure; Step 3: Obtain the maximum impact force-impact duration curve according to the ship mass and ship speed; Step 4: Input the maximum impact force-impact duration obtained in step 3 into the finite element numerical model established in step 2 to calculate the numerical simulation residual displacement of the damaged reinforced concrete structure; Step 5: Compare the numerical simulation residual displacement calculated in step 4 with the on-site detection residual displacement obtained in step 1. If the agreement is poor, change the above maximum impact force-impact duration curve, and then input it into the finite element numerical model to calculate the numerical simulation residual displacement of the damaged reinforced concrete structure again. Then compare the numerical simulation residual displacement with the on-site detection residual displacement, and repeat this process until a good agreement is achieved. Stop the calculation and obtain the final maximum impact force-impact duration curve. Step 6: Input the above-mentioned final maximum impact force-impact duration curve into the finite element numerical model for calculation, and extract the damage index of the hidden parts of the damaged reinforced concrete structure to evaluate the damage state of the damaged reinforced concrete structure.

2. The damage assessment method for a ship impacting a reinforced concrete structure according to claim 1, characterized in that: In step 1, the residual displacement detected on site is the displacement coordinate value of the damaged reinforced concrete structure minus the displacement coordinate value of the reinforced concrete structure when no collision occurs.

3. The damage assessment method for a ship impacting a reinforced concrete structure according to claim 1, characterized in that: In step 2, the method for establishing a finite element numerical model of a reinforced concrete structure is: using the entity units of large-scale general finite element software including ANSYS and ABAQUS to establish a concrete model of components including piles and beams in the reinforced concrete structure, and using beam units to establish a steel bar model, wherein the concrete and steel bar materials are respectively given a damage constitutive relationship for the concrete and an elastic-plastic constitutive relationship for the steel.

4. The damage assessment method for a ship impacting a reinforced concrete structure according to claim 1, characterized in that: In step 3, the ship mass is the ship tonnage, the ship speed is the speed recorded by the speed meter on the ship at the time of collision, the impact force at the initial moment of the ship collision is assumed to be the maximum impact force, the impact force at the end moment of the ship collision is assumed to be 0, and the impact force is linearly related to time, then the relationship between the maximum impact force and the collision duration is as follows: Where: P is the maximum impact force; M is the mass of the ship; V is the ship speed at the initial moment of the ship impact; T is the duration of the impact.

5. The damage assessment method for a ship impacting a reinforced concrete structure according to claim 1, characterized in that: In step 4, the finite element numerical model calculation uses a display algorithm to extract the displacement of the damaged reinforced concrete structure after the ship collision and the displacement of the reinforced concrete structure before the ship collision from the finite element numerical model, and the difference between the two is used to obtain the numerical simulation residual displacement of the damaged reinforced concrete structure.

6. The damage assessment method for a ship impacting a reinforced concrete structure according to claim 1, characterized in that: In step five, when comparing the numerical simulation residual displacement calculated in step four with the on-site detection residual displacement obtained in step one, if the difference is within ±5%, it is considered to be in good agreement; otherwise, if the agreement is not good, the impact duration T in step three is changed, the maximum impact force P is recalculated, a new maximum impact force-impact duration curve is obtained, and the curve is input into the finite element numerical model for calculation.

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