Performance-based seismic design method for high-pile wharf with energy dissipation

Abstract

The application provides a performance-based high-pile wharf seismic mitigation design method, and the steps are as follows: S0: determining a wharf seismic mitigation system; S1: determining a wharf seismic performance target and a panel displacement limit value; S2: performing a fortification earthquake level design to determine a design parameter of an isolation bearing; S3: performing a seismic mitigation design based on a rare earthquake level, and ensuring that the seismic mitigation wharf realizes the rare earthquake seismic performance target from the energy design angle; S4: performing a structure response check under a rare earthquake by using a nonlinear static method or a nonlinear time-history analysis method, checking a moderate earthquake and a rare earthquake displacement, and simultaneously considering material nonlinearity of a pile and the isolation bearing; and S5: performing a wharf protection component capacity design and a ship collision force check. The design method can satisfy multi-level seismic targets and realize performance-based design of the seismic mitigation wharf.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of port engineering anti-seismic technology, in particular, especially relates to a performance-based high-pile wharf seismic mitigation design method. BACKGROUND

[0002] With the increasing activity of global coastal seismic zones, the damage of high-pile wharf pile foundation caused by seismic inertia has caused a large number of port shutdown losses. In order to reduce the inertia effect of the wharf panel conducted to the pile foundation, some scholars propose a high-pile wharf seismic mitigation system. Among them, the seismic isolation bearing is arranged at the top of the pile, and the damage of the pile foundation is reduced by concentrating the plastic deformation of the wharf in the isolation layer. And by setting a damper between the pile and the panel, the energy dissipation capacity of the structure is improved. For the high-pile wharf seismic mitigation system, there is no performance-based seismic design method at present. This will hinder the standardized design and application promotion of the high-pile wharf seismic mitigation system. SUMMARY

[0003] According to the above technical problems, a performance-based high-pile wharf seismic mitigation design method is provided.

[0004] The technical means adopted by the present application are as follows:

[0005] A performance-based high-pile wharf seismic mitigation design method, comprising the following steps:

[0006] S0: determining the wharf seismic mitigation system;

[0007] S1: based on the wharf seismic mitigation system, determining the wharf seismic performance target and the panel displacement limit value;

[0008] S2: based on the panel displacement limit value, performing the fortification earthquake level design to determine the design parameters of the seismic isolation bearing;

[0009] S3: based on the design parameters of the seismic isolation bearing, performing the seismic mitigation design based on the rare earthquake level, and ensuring that the seismic mitigation wharf realizes the rare earthquake seismic performance target from the energy design angle;

[0010] S4: using the nonlinear static method or the nonlinear time history analysis method to perform the structure response checking under the rare earthquake, and checking the moderate earthquake and rare earthquake displacement, while considering the material nonlinearity of the pile and the seismic isolation bearing;

[0011] S5: performing the wharf protection component capacity design and ship collision force checking: the protection components in the wharf structure are designed by the capacity design method to ensure that the wharf protection components remain elastic; based on the reduced lateral stiffness of the wharf after isolation, the ship collision force of the designed ship type is checked.

[0012] Furthermore, in step S0, the wharf seismic isolation system is at least a straight pile wharf seismic isolation system and a forked pile wharf seismic isolation system. The wharf seismic isolation system includes at least the wharf main body, seismic isolation bearings, dampers and steel connecting beams.

[0013] Furthermore, in step S1, the panel displacement limits δ1 and δ2 of the wharf under design earthquakes and rare earthquakes are determined according to the owner's requirements or by adopting standard methods.

[0014] Furthermore, the standard method adopted is as follows: based on the layout, cross-sectional dimensions and preliminary reinforcement of the wharf pile foundation in the wharf seismic isolation system, a numerical model of the wharf is established, and pushover analysis is performed to obtain the wharf panel displacement limits δ1 and δ2 according to relevant specifications.

[0015] Furthermore, the design steps for step S2 are as follows:

[0016] S2.1: The period T of the seismic isolation wharf eff Initially set as the original terminal period T o T times; determine T eff Then, the displacement S of the seismic leveling standard for wharf seismic fortification was calculated. d and equivalent stiffness K eff ;

[0017] S2.2: Based on the principle of consistent pile stiffness, the total lateral stiffness K of the structure is... eff The loads are distributed to each pile, and the number of seismic isolation bearings n and the equivalent stiffness K of the bearings are determined iteratively. eff-i ;

[0018] S2.3: Iteratively calculate K based on the actual arrangement of the seismic isolation bearings. eff T eff ξ eff and spectral shift S d until S d Less than δ1;

[0019] S2.4: According to K eff-i S d and the damping ratio ξ of the seismic isolation bearing eff-i Determine the design parameters of the seismic isolation bearing.

[0020] Furthermore, in step S2.1, the displacement S of the response spectrum of the wharf seismic fortification level specification d Satisfy the following formula:

[0021]

[0022] In the formula, S d The displacement of the seismic level response spectrum of the isolation wharf panel is the seismic influence coefficient of the seismic acceleration response spectrum of the design earthquake.

[0023] The calculated wharf fortification earthquake level code response spectrum displacement S d Then, the S d Whether it meets the fortification earthquake level displacement limit δ1;

[0024] The equivalent stiffness K of the isolated wharf structure eff Satisfy the following formula:

[0025]

[0026] In the formula, W is the standard value of the total weight of the wharf structure;

[0027] In the step S2.3, the equivalent damping ratio ξ eff , the equivalent damping ratio of the isolated bearing on the i-th pile foundation And the damping ratio of the i-th pile foundation Satisfy the following formula:

[0028]

[0029] In the formula, Is the horizontal design displacement of the i-th pile foundation isolated bearing; Is the equivalent stiffness of the i-th pile foundation isolated bearing; Is the lateral stiffness of the i-th pile foundation; Is the equivalent viscous damping ratio of the i-th isolated bearing; Is the equivalent viscous damping ratio of the i-th pile foundation;

[0030] The obtained equivalent damping ratio ξ eff , the panel displacement S d And δ1 Whether it meets the fortification earthquake level design target;

[0031] In the step S2.4, the friction pendulum isolated bearing is used for isolation design, and a hysteretic model is established; The friction coefficient and the radius of curvature of the isolated bearing satisfy the following formula:

[0032]

[0033] In the formula, k i Is the initial stiffness of the isolated bearing; D y Is the yield displacement of the bearing; D d Is the horizontal design displacement of the isolated bearing; μ is the friction coefficient; k fps Is the swing stiffness of the friction pendulum bearing; k eff-i Is the equivalent stiffness of the isolated bearing; W is the axial force on the isolated bearing; R is the radius of curvature of the friction pendulum.

[0034] Further, the step S3 specifically includes the following steps:

[0035] S3.1: Initial setting of damper equivalent stiffness K damper and the equivalent period T of the isolated wharf eff,MCE ;

[0036] The constitutive model of the friction damper is established, and the friction force is set as F s , the MCE seismic design displacement is δ2, and the stiffness ratio of the isolation device composed of the damper and the support to the pile is β, and the following is obtained:

[0037] β = (k damper +k eff-i.MCE ) / k batter <0.3;

[0038] k damper = F s / δ2;

[0039] k eff-i,MCE = μW b / δ2;

[0040] In the formula, k damper and k eff-i,MCE are the equivalent stiffnesses of the friction damper and the isolation support at the MCE seismic level respectively; k batter is the total stiffness of the pile;

[0041] The equivalent period T of the isolated wharf eff,MCE satisfies the following formula:

[0042]

[0043] In the formula, k eff,MCE is the equivalent stiffness of the isolated wharf;

[0044] S3.2: Determining the seismic input energy;

[0045] The wharf deck spectral velocity S eff,MCE is determined by the equivalent period T of the isolated wharf v and the MCE design response spectrum, and the seismic input energy is obtained by the wharf deck spectral velocity S v , and the seismic input energy satisfies the following formula:

[0046] E in = 1 / 2MS v 2 ;

[0047] In the formula, E in is the input seismic energy of the structure equivalent to an elastic single-degree-of-freedom system, and M is the design mass of the structure;

[0048] Suppose that the energy of the earthquake input is all dissipated by the friction damper, and the energy dissipation of the friction pendulum is as a reserve. To consume the energy of the earthquake input, the damper designs the friction force F s Should be greater than the friction force requirement F sd . The damper friction force requirement F sd Satisfies the following formula:

[0049]

[0050] In the formula, Is the conversion coefficient of the energy dissipation of a single circle of the damper and the total energy dissipation of the earthquake; Is the reduction coefficient considering the insufficient energy dissipation of the damper.

[0051] Further, in the step S4, the nonlinear time history analysis method adopts 3 groups and above time histories, wherein when the time histories adopted are less than 7 groups, the structure response result is the maximum value of the response of each group of time histories; when 7 groups or more time histories are adopted for analysis, the structure response result is the average value of the analysis.

[0052] Further, in the step S5, the wharf protection member at least includes a wharf panel, an isolation pile, an isolation support connecting piece, a damper and a steel link beam, the seismic demand of the wharf protection member under bending and shearing is checked, and the seismic demand is less than the design bearing capacity of the member.

[0053] Compared with the prior art, the present application has the following advantages:

[0054] 1. The wharf seismic mitigation and isolation design method proposed in the present application can meet multi-level seismic resistance targets and realize the performance-based design of the seismic mitigation and isolation wharf.

[0055] 2. The seismic mitigation and isolation wharf can realize a higher seismic fortification level than the non-isolation wharf (using the same pile type), realize the repairable level under rare earthquakes, and effectively improve the seismic resistance of the wharf in high seismic intensity areas.

[0056] 3. The seismic isolation measures of the seismic mitigation and isolation wharf eliminate the movement of the vulnerable pile and the panel, protect the pile body, increase the structure period, and reduce the seismic inertia force. At the same time, the damper increases the energy dissipation capacity and controls the seismic displacement of the structure. The structure has high energy dissipation capacity and controllable response under the premise of reasonable damage mechanism.

[0057] Based on the above reasons, the present application can be widely popularized in the field of seismic resistance and the like. BRIEF DESCRIPTION OF DRAWINGS

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments or prior art description. Obviously, the drawings described below are only some embodiments of the present application, and the ordinary skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0059] Figure 1 Flow chart of the performance-based seismic mitigation design method of the high-pile wharf of the present application.

[0060] Figure 2 Schematic diagram of the seismic mitigation design steps of the high-pile wharf of the present application.

[0061] Figure 3 Schematic diagram of the seismic mitigation system of the high-pile wharf of the present application, wherein (a) is the seismic mitigation system of the straight-pile wharf, and (b) is the seismic mitigation system of the forked-pile wharf.

[0062] Figure 4 Schematic diagram of the hysteretic model of the friction pendulum bearing.

[0063] Figure 5 The constitutive model of the friction damper. DETAILED DESCRIPTION

[0064] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0065] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by the ordinary skilled in the art without any creative effort belong to the scope of protection of the present application.

[0066] It should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, there is a presence of the features, steps, operations, devices, components and / or their combinations.

[0067] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples herein are not intended to limit the scope of the application unless otherwise specifically stated. It is to be understood that the drawings are not necessarily to scale as the dimensions of the parts shown are for the purpose of illustration and description only and not limitation of the scope of the application. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail but are intended to be part of the scope of the application. In all examples shown and discussed herein, any specific values should be interpreted as merely illustrative and not limiting. Other examples of the exemplary embodiments can therefore have different values. It is noted that like numbers and letters refer to like elements throughout the several views of the drawings and, as such, no further discussion with regard thereto is deemed necessary.

[0068] The present application provides a performance-based seismic design method for high-pile wharf with seismic isolation, which is a two-stage performance-based seismic design method for high-pile wharf with seismic isolation. The arrangement scheme and design parameters of the isolation bearings are determined based on the seismic level, and the displacement response of the wharf is calculated based on the rare earthquake level.

[0069] The design method of the present application comprises the following steps:

[0070] S0: determining the seismic isolation system of the wharf;

[0071] S1: determining the seismic performance target and the panel displacement limit of the wharf based on the seismic isolation system of the wharf;

[0072] S2: performing design at the seismic level based on the panel displacement limit to determine the design parameters of the isolation bearings;

[0073] S3: performing seismic design based on the rare earthquake level based on the design parameters of the isolation bearings, and ensuring that the seismic isolation wharf achieves the rare earthquake performance target from the energy design point of view;

[0074] S4: performing the checking of the structure response under rare earthquake by using the nonlinear static method or the nonlinear time history analysis method, and checking the displacement under the rare earthquake and the rare earthquake, while considering the material nonlinearity of the pile and the isolation bearing;

[0075] S5: performing the capacity design of the protective components of the wharf and the ship collision force checking: the protective components in the wharf structure are designed by the capacity design method to ensure that the protective components of the wharf remain elastic; based on the reduction of the lateral stiffness of the wharf after isolation, the ship collision force of the designed ship type is checked.

[0076] As a preferred embodiment, in step S1, the panel displacement limits δ1, δ2 of the wharf under the design earthquake and the rare earthquake can be determined in two ways. Way one: according to the requirements of the owner; way two: determining δ1, δ2 by using the specification method. Since the arrangement of the wharf pile foundation, the cross-sectional size and the preliminary reinforcement amount are usually determined at the structural gravity design stage. Therefore, a numerical model of the wharf can be established to perform pushover analysis, and the displacement limits δ1, δ2 of the wharf are obtained according to the relevant specifications.

[0077] As a preferred embodiment, in step S2, the design parameters of the isolation bearing are determined based on the displacement limit δ1 of the wharf isolation system under the design earthquake level and the principle of consistent pile stiffness.

[0078] As a preferred embodiment, in step S2, the calculation model adopts a transverse single-row frame elastic bar system model. Since the mass and stiffness of the wharf are concentrated in the upper panel and the pile body respectively, the calculation model can be regarded as a single degree of freedom system, and the linear response spectrum method is used for analysis. The pile-soil interaction of the wharf is considered by using the virtual embedded point method. For the elastic-plastic isolation bearing, the equivalent linearization method is used to treat it as an elastic system.

[0079] Alternatively, the virtual embedded point method can use the relevant formulas and requirements in the specifications “JTS167-4-2012 Port Engineering Pile Foundation Specification”, “ASCE61-14 Seismic Design of Piers and Wharves” and “Technical Standards and Commentaries for Port and Harbour Facilities in Japan”.

[0080] As a preferred embodiment, in step S2, the following calculation steps are used:

[0081] Step S2.1: The fundamental period of the isolated wharf is generally greater than 2.0 compared with the non-isolated wharf. Therefore, the period T eff of the isolated wharf can be initially set as twice the period T o of the original wharf.

[0082] Step S2.2: Based on the principle of consistent pile stiffness, the total lateral stiffness K eff of the structure is distributed to each pile, and the number n of isolation bearings to be arranged and the equivalent stiffness K eff-i of the bearing are determined. Since there is a certain adjustment space for the stiffness distribution of the isolation pile at this stage, several distribution schemes usually need to be determined, and the optimal one is selected after comprehensive comparison.

[0083] Step S2.3: According to the actual arrangement of the bearing, K eff , T eff and ξeff and spectrum displacement S d , until S d should be less than δ1.

[0084] Step S2.4: according to K eff-i , S d and isolation bearing damping ratio ξ eff-i determine the isolation bearing design parameters.

[0085] As a preferred embodiment, in step S3, based on the wharf isolation design, the rare earthquake level-based vibration reduction design is carried out to reduce the wharf seismic displacement and ensure that the rare earthquake performance target of the rare earthquake is achieved from the energy design point of view.

[0086] As a preferred embodiment, in step S4, the designed rare earthquake and rare earthquake displacement of the rare earthquake isolation wharf are calculated by using the nonlinear static method or the time history analysis method. The nonlinear time history analysis method should use 3 groups or more time histories. If less than 7 groups of time histories are used, the maximum value of the response of each group of time histories is taken as the structure response result; if 7 groups or more time histories are used for analysis, the average value of the analysis can be taken as the structure response result.

[0087] As a preferred embodiment, in step S5, the wharf protection member includes a panel, an isolation bearing connector, a damper, a steel connecting beam, etc.

[0088] As a preferred embodiment, in step S5, the isolation pile top section should have sufficient bending and shear strength. The present application uses a 1.25 times super-strength coefficient to calculate the bending capacity of the panel and the steel connecting beam, and the bending and shear capacity of the isolation pile top.

[0089] Embodiment 1

[0090] The application discloses a two-stage rare earthquake isolation design method for a high-pile wharf based on performance. The isolation bearing arrangement scheme and design parameters are determined based on the fortification earthquake level, and the wharf displacement response is calculated based on the rare earthquake level.

[0091] As shown in Figures 1-2 , taking a fork pile system as an example, the rare earthquake isolation design method for a high-pile wharf based on performance is introduced:

[0092] Step S0: determine the rare earthquake isolation system of the wharf.

[0093] Preferably, the rare earthquake isolation system of the wharf adopts the structure shown in Figure 3 , including a straight pile wharf rare earthquake isolation system and a fork pile wharf rare earthquake isolation system. The rare earthquake isolation system of the wharf includes a wharf main body, an isolation bearing, a damper and a steel connecting beam.

[0094] Preferably, for the wharf on the inclined bank, the purpose of the isolation is to control the wharf damage mode and eliminate the local damage of the near-shore side pile caused by the stiffness concentration. Therefore, when arranging the isolation bearing, the principle of balancing the lateral frame pile lateral stiffness should be considered to make all piles evenly distribute the seismic action. Therefore, the arrangement sequence of the isolation bearing can start from the near-shore side pile with larger stiffness, and the number and specification of the isolation bearing should be determined by the design seismic demand and the pile foundation calculated by the balance condition of the pile stiffness.

[0095] Preferably, in the seismic mitigation system of the straight pile wharf, the present application installs the damper in the inclined direction between the sea side piles, dissipates the seismic energy by the relative deformation of the sea side piles, and controls the wharf seismic displacement at a similar level to the original wharf.

[0096] Preferably, in order to increase the stiffness and integrity of the isolation pile, the present application proposes to install a steel coupling beam between the isolation piles to ensure that the horizontal deformation of the high-pile wharf under the seismic action is concentrated in the isolation layer. Figure 3 )。

[0097] Step S1: Determine the seismic performance target and panel displacement limit of the wharf.

[0098] Optionally, in step S1, the seismic performance target and panel displacement limit δ1, δ2 of the wharf under the fortification earthquake and the rare earthquake can be determined in two ways.

[0099] Method one: according to the requirements of the owner;

[0100] Method two: determine δ1, δ2 by using the specification method. Since the arrangement, cross-sectional size and preliminary reinforcement of the wharf pile foundation are usually determined in the structure gravity design stage, a numerical model of the wharf can be established for pushover analysis, and the wharf panel displacement limit δ1, δ2 can be obtained according to the relevant specification.

[0101] Preferably, the Seismic Design of Piers and Wharves (ASCE 61-14) gives the three-level seismic fortification target of the high-pile wharf, and specifies the damage state of the wharf under each seismic level under different fortification levels. The present application refers to the high-pile wharf fortification target given in ASCE 61-14 (2014) as shown in Table 1.

[0102] Table 1: Multi-level fortification target of high-pile wharf

[0103]

[0104]

[0105] Further, the definition and quantification index of each damage state of the pile foundation refer to ASCE61-14, wherein the damage state is divided according to the material strain size of the plastic hinge at the top of the pile, in the soil of the pile and at the deep foundation. In the seismic design of the high-pile wharf, the material strain needs to be converted into the structural displacement as the design index. In order to obtain the displacement design limit value of the wharf at different fortification earthquake levels, the numerical method is used to carry out the pushover analysis of the wharf structure. In the analysis, by continuously increasing the horizontal displacement of the panel, the time when the strain of the most unfavorable pile (i.e. the pile with the most serious damage in the wharf) reaches the limit value is monitored, and the displacement of the panel at this moment is taken as the displacement design limit value of the wharf at a certain fortification earthquake level.

[0106] Step S2: Perform fortification earthquake level design to determine the parameters of the isolation bearing. The following calculation steps are adopted:

[0107] Step S2.1: The basic period of the isolated wharf is generally greater than 2.0 compared with the non-isolated wharf. Therefore, the period T eff of the isolated wharf can be initially set as twice the period T o of the original wharf, and the equivalent damping ratio ξ eff can be initially set as 0.1. After determining T eff , the wharf fortification earthquake level specification response spectrum displacement S d and the equivalent stiffness K eff are calculated.

[0108] Preferably, the wharf fortification earthquake level specification response spectrum displacement S d is calculated by formula (1), and whether S d meets the fortification earthquake level displacement limit value δ1 is checked.

[0109]

[0110] In the formula, S d is the panel fortification earthquake level response spectrum displacement of the isolated wharf, and C is the seismic influence coefficient of the fortification earthquake acceleration response spectrum, which is obtained from the Code for Seismic Design of Buildings (GB50011-2010) (2016).

[0111] Preferably, the equivalent stiffness K eff of the isolated wharf structure is calculated by formula (2).

[0112]

[0113] In the formula, W is the total weight standard value of the wharf structure.

[0114] Step S2.2: Based on the principle of uniform pile stiffness, the total lateral stiffness K eff of the structure is distributed to each pile, and the number n of isolation bearings to be arranged and the equivalent stiffness K eff-iSince there is some room for adjustment in the stiffness distribution of the seismic isolation piles at this stage, it is usually necessary to determine several distribution schemes and select the best one after comprehensive comparison.

[0115] Preferably, the focus of seismic isolation design for wharves is to reduce the stiffness concentration effect of near-shore side piles. Therefore, with the goal of making the lateral stiffness of each pile as consistent as possible, the overall equivalent stiffness K of the seismic isolation wharf is set at... eff The pile spacing is determined to establish the number of seismic isolation piles and the equivalent stiffness K of the seismic isolation bearings. eff-i .

[0116] Step S2.3: Iteratively calculate K based on the actual support layout. eff T eff ξ eff and spectral shift S d until S d It should be less than δ1.

[0117] Preferably, the equivalent damping ratio ξ of the seismic isolation wharf eff The equivalent damping ratio of the seismic isolation bearing on the i-th pile foundation Damping ratio with the i-th pile foundation The relationship is shown in formula (3):

[0118]

[0119] In the formula, The horizontal design displacement of the i-th pile foundation seismic isolation bearing can be approximated by the panel spectrum displacement S. d ; Let be the equivalent stiffness of the i-th pile foundation seismic isolation bearing; Let be the lateral stiffness of the i-th pile foundation; Let be the equivalent viscous damping ratio of the i-th seismic isolation bearing, taken as 0.3; Let be the equivalent viscous damping ratio of the i-th pile foundation, taken as 0.05.

[0120] Furthermore, the equivalent damping ratio ξ' of the wharf can be obtained from formula (3). eff The panel displacement S' is calculated using formula (1). d Compare with δ1 to see if it meets the design target of the earthquake-resistant level.

[0121] Step S2.4: According to K eff-i S d and the damping ratio ξ of the seismic isolation bearing eff-i Determine the design parameters of the seismic isolation bearing.

[0122] Preferably, the present invention uses a friction pendulum isolation bearing for seismic isolation design, and its hysteresis model is as follows: Figure 4 As shown.

[0123] Preferably, the formulas for calculating the friction coefficient and radius of curvature of the seismic isolation bearing are as shown in formula (4) and formula (5).

[0124]

[0125] exist Figure 4 In the middle, k i D represents the initial stiffness of the seismic isolation bearing. y D represents the support yield displacement. d The horizontal design displacement of the seismic isolation bearing is given; μ is the friction coefficient; k fps k represents the oscillation stiffness of the friction pendulum support. eff-i denoted as the equivalent stiffness of the seismic isolation bearing; W is the axial force acting on the seismic isolation bearing; and R is the radius of curvature of the friction pendulum.

[0126] Step S3: Based on the above seismic isolation design steps, conduct seismic reduction design based on the level of rare earthquakes.

[0127] Step S3.1: Initially set the equivalent stiffness K of the damper damper Equivalent period T of the seismic isolation wharf eff,MCE .

[0128] Preferably, the constitutive model of the friction damper is as follows: Figure 5 As shown, let the frictional force be F. s The MCE seismic design displacement is δ2. Assuming the stiffness ratio of the seismic isolation device (including dampers and bearings) to the pile is β, then:

[0129] β=(k damper +k eff-i.MCE ) / k batter <0.3 (6)

[0130] k damper =F s / δ2 (7)

[0131] k eff-i,MCE =μW b / δ2 (8)

[0132] In the formula, k damper and k eff-i,MCE These are the equivalent stiffnesses of the friction damper and the seismic isolation bearing at the MCE seismic level, respectively. batter This represents the total stiffness of the fork pile.

[0133] Furthermore, the equivalent period T of the seismic isolation wharf eff,MCE for:

[0134]

[0135] In the formula, k eff,MCE To reduce the equivalent stiffness of the seismic isolation wharf.

[0136] Step S3.2: Determine the seismic input energy.

[0137] Preferably, the equivalent period T eff,MCE of the isolated wharf is determined by the formula (10). v The wharf deck spectrum velocity S in is determined by the formula (11) and the MCE design response spectrum. v 2 (11)

[0138] E in = 1 / 2MS sd

[0139] In the formula, E sd is the input seismic energy of the structure equivalent to an elastic single degree of freedom system, and M is the design mass of the structure.

[0140] Further, the friction force requirement F sd of the damper is calculated.

[0141] For conservative design, it is assumed that the seismic input energy is entirely dissipated by the friction damper, and the energy dissipation of the friction pendulum is used as a reserve. The total friction force requirement F sd of the damper is determined by the formula (12). The design friction force F s of the damper should be greater than the friction force requirement F sd .

[0142]

[0143] In the formula, C is the conversion coefficient of the energy dissipation of a single circle of the damper and the total seismic energy dissipation, and is taken as 2, is the reduction coefficient considering insufficient energy dissipation of the damper, and is taken as 0.7.

[0144] Step S4: Perform rare earthquake level design and check the structure displacement. The nonlinear time history analysis method is used to check the structure response under rare earthquakes, and the material nonlinearity of the pile and the isolation bearing needs to be considered at this time.

[0145] Optionally, the numerical model of the isolated wharf can use a two-dimensional or three-dimensional wharf numerical model. For the interaction between the pile and the soil, the virtual embedded point method, the p-y curve method or the integral method can be used.

[0146] Preferably, in step S4, the nonlinear time history analysis method should use 3 or more time histories. If less than 7 time histories are used, the maximum value of the responses of each group of time histories is taken as the structure response result; if 7 or more time histories are used for analysis, the average value of the analysis can be taken as the structure response result.

[0147] Preferably, the ground motion information is selected from the PEER database and is adjusted to the rare earthquake level. The selected ground motion response spectrum should match well with the design response spectrum in the range of the natural period of the wharf.

[0148] Step S5: Perform wharf protection member capacity design and ship collision force checking. Design the protection members in the wharf structure through the capacity design method to ensure that these members remain elastic. Due to the reduction in lateral stiffness after the isolation of the wharf, the ship collision force of the designed ship type should also be checked.

[0149] Preferably, according to the wharf displacement under ship impact according to the Chinese “Port Engineering Load Specification (JTS144-1-2010)” and “Rubber Fender (HG-T2866-2016)”, and compared with the elastic displacement limit value of the wharf.

[0150] Further, in step S5, the bending and shearing requirements of the wharf panel, the connecting beam, the damper and the isolation pile and other capacity protection members are checked, and the seismic demand should be less than the design bearing capacity of the member.

[0151] Further, in step S5, the top section of the isolation pile should have sufficient bending and shearing strength. The present application uses a 1.25 times super strength coefficient to check the bending bearing capacity of the panel and the steel connecting beam, and the bending and shearing bearing capacity of the top of the isolation pile.

[0152] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A performance-based seismic design method for a high-pile wharf with seismic mitigation, characterized by, The method comprises the following steps: S0: determining a wharf reduction and isolation system; S1: determining a wharf seismic performance target and a panel displacement limit value based on the wharf reduction and isolation system; S2: performing fortification earthquake level design based on the panel displacement limit value to determine design parameters of the isolation bearing; S3: performing seismic reduction design based on the design parameters of the isolation bearing at a rare earthquake level, and ensuring that the reduction and isolation wharf achieves the rare earthquake seismic performance target from the perspective of energy design; S4: performing a check on structural response under a rare earthquake by using a nonlinear static method or a nonlinear time history analysis method, checking the displacement under a moderate earthquake and a rare earthquake, and simultaneously considering the material nonlinearity of the pile and the isolation bearing; S5: performing a capacity design of a wharf protection component and a ship collision force check: a capacity design method is used to design a protection component in the wharf structure to ensure that the wharf protection component remains elastic; and a ship collision force check is performed for a designed ship type based on the reduction of the lateral stiffness of the wharf after isolation; In the step S0, the wharf reduction and isolation system is at least a straight pile wharf reduction and isolation system or a forked pile wharf reduction and isolation system, and the wharf reduction and isolation system at least comprises a wharf main body, an isolation bearing, a damper, and a steel coupling beam. In step S1, the panel displacement limit value of the wharf under the fortification earthquake is determined according to the owner's requirement or by using a specification method In the step S2, the design steps are as follows: 1 and the panel displacement limit value under the rare earthquake In the step S2.4, a friction pendulum isolation bearing is used for isolation design, and a hysteretic model is established; the friction coefficient and the curvature radius of the isolation bearing satisfy the following formula: 2; The adopted standard method is: based on the layout of pier foundation, section size and preliminary reinforcement of the pier isolation system in the wharf, the numerical model of the wharf is established, and the pushover analysis is carried out, and the panel displacement limit value of the fortification earthquake is obtained according to the standard of ASCE 61-14 Seismic Design of Piers and Wharves in 2014 The step S3 specifically comprises the following steps: 1、Panel displacement limit value of rare earthquake In the step S4, the nonlinear time history analysis method uses three or more time histories; when the time histories used are less than seven, the maximum value of the structural response results of each group of time histories is taken; and when seven or more time histories are used for analysis, the average value of the structural response results is taken. 2; In the step S5, the wharf protection component at least comprises a wharf panel, an isolation pile, an isolation bearing connecting piece, a damper, and a steel coupling beam, the seismic demand of the wharf protection component under bending and shearing is checked, and the seismic demand is less than the design bearing capacity of the component. S2.1: The period of the seismic isolation wharf T eff Initially set as the original dock cycle T o Twice; determined T eff Then, the structural seismic design code response spectrum displacement was calculated. S d and structural lateral stiffness K eff ; S2.2: Based on the principle of uniform pile stiffness, the lateral stiffness of the structure is distributed to each pile, and the number of isolation bearings that need to be arranged is determined iteratively K eff n Equivalent stiffness of isolation bearings K eff-i ;​ S2.3: Iterative calculation according to actual arrangement of the isolation bearings K eff 、 T eff 、 ​ eff and S d until S d less than ​ 1; S2.4: determining the design parameters of the seismic isolation bearings according to K eff-i , S d and the damping ratio of the seismic isolation bearings ​ eff-i determining the design parameters of the seismic isolation bearings; In the step S2.1, the structure fortification earthquake code response spectrum displacement S d satisfies the following equation: ； In the formula, S d For the structural earthquake resistant design spectrum displacement, C For the earthquake acceleration response spectrum seismic influence coefficient; The calculated structural design earthquake code response spectrum displacement S d Then, checking S d Whether the panel displacement limit value meets the design earthquake ​ 1; Structural lateral stiffness of a seismic isolated wharf K eff satisfies the following equation: ； In the formula, W is the standard value of the total gravity of the wharf structure; In the step S2.3, the equivalent damping ratio of the wharf ​ eff , the equivalent viscous damping ratio of the first i , the equivalent viscous damping ratio of the first pile foundation i satisfies the following formula:​​ ； In the formula, For the first i Horizontal design displacement of each pile foundation seismic isolation bearing; For the first i Equivalent stiffness of each pile foundation seismic isolation bearing; For the first i Lateral stiffness of each pile foundation; For the first i The equivalent viscous damping ratio of each seismic isolation bearing; For the first i The equivalent viscous damping ratio of each pile foundation; According to the actual arrangement of the isolation bearing, the equivalent damping ratio of the wharf is iteratively calculated ​ eff , the structural seismic code response spectrum displacement S d , the S d and ​ 1. Whether the comparison meets the design target of the seismic level ​ ； ； wherein D d is the horizontal design displacement of the isolation bearing; is the friction coefficient; K eff-i is the equivalent stiffness of the isolation bearing; W b is the axial force of the isolation bearing; R is the friction pendulum radius of curvature; ​ S3.1: Initial setup of the equivalent stiffness of the friction damper K damper and the equivalent period of the isolated seismic wharf T eff,MCE ; The constitutive model of friction damper is established, and the design friction of damper is F s , the panel displacement limit value of rare earthquake is ​ 2, and the stiffness ratio of the friction damper and the pile is β , and the following is obtained: β =( K damper + K eff-i,MCE ) / K b ＜0.3； K damper = F s / ​ 2； K eff-i,MCE = ​ b / ​ 2； wherein, K damper and K eff-i,MCE respectively are the equivalent stiffness of the friction damper and the equivalent stiffness of the isolation bearing under rare earthquake; K b is the pier leg stiffness; W b is the isolation bearing axial force; Seismic-isolation equivalent period of a wharf T eff,MCE satisfies the following equation: ； ； wherein K eff,MCE Kp is the equivalent stiffness of the shock-absorbing wharf; K p Kp is the equivalent stiffness of the shock-absorbing wharf; K b Kp is the equivalent stiffness of the shock-absorbing wharf; ​ By reducing the equivalent period of the seismic isolation wharf T eff,MCE And rare earthquake design response spectrum to determine the wharf panel spectrum velocity S v , through the wharf panel spectrum velocity S v The seismic input energy is obtained, and the seismic input energy satisfies the following formula: E in =1 / 2 ​ v 2 ； In the formula, E in is the energy input by the earthquake, M is the design quality of the structure; ​ To dissipate the seismic input energy, the damper is designed with friction force F s greater than the damper friction force requirement F sd ; the damper friction force requirement F sd satisfies the following equation: ； In the formula, ​ 1 is the conversion coefficient of the energy dissipation of the damper single ring and the total energy dissipation of the earthquake; ​ 2 is the reduction coefficient considering the insufficient energy dissipation of the damper.

2. The performance-based seismic design method of a high-pile wharf with energy reduction according to claim 1, wherein, ​ 3. The performance-based seismic design method of a high-pile wharf with energy reduction according to claim 1, wherein, ​

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