Prefabricated bridge pier suitable for earthquake high-intensity area and construction method of prefabricated bridge pier

Abstract

According to the prefabricated pier suitable for the earthquake high-intensity area and the construction method of the prefabricated pier, a plurality of longitudinal bars are arranged in an upper prefabricated part, and a plurality of connecting bars are arranged in a lower prefabricated part; the connector provided by the invention can generate enough extrusion force to ensure the connection performance of the rib material in the connector, the end part of the connector main body is expanded and is mutually matched with the wedge-shaped support ring, so that the connection performance of the rib material in the connector is improved, and the connection performance of the rib material in the connector is improved. The supporting rings and the rib materials are embedded and fixed and transmit force through the protrusions and the grooves at the same time, the prefabricated assembly structure can have better integrity at the connecting position, the problem that a prefabricated structure is prone to generating large damage at the connecting position or the pier bottom under the action of earthquake loads is solved, and the structure can give full play to the ductility performance.

Description

Technical Field

[0001] The invention belongs to the technical field of prefabricated assembled bridges, and relates to a prefabricated assembled bridge pier suitable for high-intensity earthquake zones and a construction method thereof. Background Art

[0002] The prefabricated pier system is an effective way and important means to achieve the "good and fast" requirements for bridge construction in the new era. Compared with traditional cast-in-place concrete piers, the prefabricated pier system has great advantages such as being able to solve the construction interference problem of adjacent operating lines, improving the quality of piers through factory prefabrication of pier segments, shortening on-site construction workload, saving construction time, improving the green level of engineering construction, and saving construction industry resources.

[0003] At present, the existing connection methods of prefabricated pier columns mainly include grouting sleeve connection, grouting bellows connection, cast-in-place wet joint connection, post-tensioned prestressed connection and socket connection. However, the bridge piers formed by the existing connection methods have shortcomings in terms of stress performance that need to be solved urgently. For example, the grouting sleeve connection method cannot fully exert the performance of the longitudinal reinforcement, so that the ductility of the pier column cannot be fully developed, and grouting defects may occur, thus affecting its connection performance; the grouting bellows connection has the problem of difficult positioning and the bellows is easy to deform, so it cannot provide sufficient strength; the on-site pouring of the cast-in-place wet joint is large in workload and long in construction period, which has a great impact on the surrounding environment; the post-tensioned prestressed connection has the problem of not being able to balance the energy dissipation capacity and self-reset capacity.

[0004] For example, patent CN116377862 B discloses a joint test method for prefabricated piers, caps and cap beams. By using steel bar lap joints and pouring UHPC at the joints formed by the piers, caps and cap beams, the joint width is greatly reduced, the joint reinforcement is simplified, and the steel bar welding is reduced, thereby improving the performance of the prefabricated structure, including fatigue resistance, earthquake resistance, crack resistance and durability. However, in this method, the joint is the weak point of the pier, the ductility at the connection node is poor, and the column section is weakened more, which affects the strength and stiffness of the prefabricated column. The strain concentration phenomenon is obvious and the deformation is severe. It is easy to be damaged in advance before the ductility of the pier body is fully developed, causing the longitudinal reinforcement performance at the joint to fail prematurely. Compared with cast-in-place piers, there are shortcomings such as poor integrity and weak hysteresis capacity. Therefore, how to propose a connection structure that can take into account the energy dissipation capacity and self-reset capacity of the prefabricated pier and achieve fast and convenient construction under the premise of ensuring the connection strength is an urgent problem to be solved. Summary of the invention

[0005] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a prefabricated assembled bridge pier and a construction method thereof suitable for high earthquake intensity areas, so as to solve the problem that the construction of the existing assembled bridge pier connection section is complicated and cannot take into account both energy consumption capacity and self-resetting capacity.

[0006] To solve the above problems, the technical solution adopted by the present invention is:

[0007] A prefabricated and assembled bridge pier suitable for use in areas with high earthquake intensity, comprising an upper prefabricated component 1 and a lower prefabricated component 2, wherein a plurality of longitudinal bars 3 are arranged inside the upper prefabricated component 1, and a plurality of connecting bars 4 are arranged inside the lower prefabricated component 2;

[0008] A raised portion 1-2 is provided at the bottom of the upper prefabricated component 1, and the cross-sectional area of ​​the raised portion 1-2 is smaller than the original cross-sectional area of ​​the upper prefabricated component 1; the portion of the longitudinal reinforcement 3 extending in the raised direction is the upper reinforcement reserved section 3-1, and the upper reinforcement reserved section 3-1 is located in the area outside the raised portion;

[0009] A groove portion is provided at the top of the lower prefabricated component 2, the bottom opening of the groove portion is larger than the top opening, and the cross-section is trapezoidal; the portion of the connecting rib 4 extending from the top surface of the groove portion is a connecting rib reserved section 4-1, and the connecting rib reserved section 4-1 is connected to the upper rib reserved section 3-1 in a one-to-one correspondence; the raised portion of the upper prefabricated component 1 is inserted into the groove portion of the lower prefabricated component 2.

[0010] The upper reinforcement reserved section 3-1 is connected to the connecting reinforcement reserved section 4-1 through a reinforcement connector 5. Specifically, a non-bonded section 8 is arranged above the connection between the end of the upper reinforcement reserved section 3-1 and the reinforcement connector 5, and multiple layers of closed stirrups 7 are arranged on the periphery of the upper reinforcement reserved section 3-1. Post-cast concrete 6 is arranged on the periphery of the upper raised part 1-2 and the groove part of the lower prefabricated component 2, so that the upper prefabricated component 1 and the lower prefabricated component 2 form a whole.

[0011] The reinforcement connector 5 includes a connector body 5-1, an internal limit protrusion 5-1-1 and an external limit protrusion 5-1-2 are respectively arranged inwardly and outwardly in the middle of the connector body 5-1, and a top groove 5-1-3 and a bottom groove 5-1-4 are respectively arranged at the top and bottom of the connector body 5-1; the upper reinforcement reserved section 3-1 is inserted into the top groove 5-1-3 for anchoring, and the connecting reinforcement reserved section 4-1 is inserted into the bottom groove 5-1-4 for anchoring; the top and bottom of the connector body 5-1 are respectively connected to the top connecting sleeve 5-2 and the bottom connecting sleeve 5-3 by threads, and the top groove 5-1-3 and the upper reinforcement reserved section 3-1, and the bottom groove 5-1-4 and the connecting reinforcement reserved section 4-1 are both in close contact through the support ring 5-4.

[0012] The top connecting sleeve 5-2 and the bottom connecting sleeve 5-3 both include a large diameter end and a small diameter end, wherein the large diameter end is provided with an internal thread connected to the external threads at the top and bottom of the connector body 5-1; the inner diameter of the small diameter end is adapted to the outer diameter of the upper rib reserved section 3-1 and the connecting rib reserved section 4-1.

[0013] The top and bottom of the connector body 5-1 are provided with a plurality of non-through axial slits 5-1-5, the inner surface of the top end and the inner surface of the bottom end of the connector body 5-1 are both outwardly expanded, the support ring 5-4 is in the shape of a hollow inverted truncated cone, and the outer surface of the support ring 5-4 is adapted to the inner surface of the top end and the inner surface of the bottom end of the connector body 5-1;

[0014] The surfaces of the upper reinforcement reserved section 3-1 and the connecting reinforcement reserved section 4-1 are both provided with an annular groove 9, the inner surface of the support ring 5-4 is provided with a support ring protrusion 5-4-2 matching the annular groove 9, the support ring protrusion 5-4-2 is embedded in the annular groove 9, the outer surface of the support ring 5-4 is provided with an axial groove 5-4-1, the depth of the axial groove 5-4-1 is less than the thickness of the support ring 5-4, and the support ring 5-4 is provided with a disconnection gap 5-4-3 opposite to the axial groove 5-4-1.

[0015] The anchoring length L of the upper reinforcement reserved section 3-1 and the connection reinforcement reserved section 4-1 in the reinforcement connector 5 an Need to meet:

[0016]

[0017] in,

[0018] A t =0.785(d-0.94P) 2

[0019] E s,min =d-0.65P

[0020] K n,max =d-1.08P

[0021] Where, L an is the anchorage length, d is the bar diameter, and P is the thread pitch; A t is the equivalent area corresponding to the thread diameter, E s,min is the elastic modulus of the thread material, K n,max The thread diameter.

[0022] The depth of the top groove 5-1-3 and the bottom groove is greater than the anchoring length L an .

[0023] The length of the raised portion 1-2 of the upper prefabricated component 1 must meet the following requirements:

[0024]

[0025] Where l is the side length or diameter of the pier cross section, and h is the pier height;

[0026] The top opening width of the groove portion of the lower prefabricated component 2 must meet the following requirements:

[0027]

[0028] The calculation formula for the bottom opening width of the groove portion of the lower prefabricated component 2 is:

[0029] B b =0.575B u +3.925.

[0030] The longitudinal reinforcement 3 and the corresponding connecting reinforcement 4, which account for more than 20% and are not less than 2, are made of shape memory alloy material; the post-cast concrete 6 is made of ultra-high performance concrete or shape memory alloy fiber concrete.

[0031] A method for constructing prefabricated bridge piers suitable for areas with high earthquake intensity, comprising the following steps:

[0032] S1: Tie up the steel cage of the upper prefabricated component 1 and install the formwork, pour concrete, and prepare the upper prefabricated component 1. At this time, the longitudinal reinforcement 3 extends out of the upper reinforcement reserved section 3-1 along the convex direction of the convex part 1-2 of the upper prefabricated component 1, and a non-bonded section 8 is arranged on the upper reinforcement reserved section 3-1;

[0033] S2: Tie the steel cage of the lower prefabricated component 2 and install the formwork, pour concrete, and prepare the lower prefabricated component 2. At this time, the connecting bar 4 extends out of the connecting bar reserved section 4-1 on the top surface of the groove part of the lower prefabricated component, corresponding to the upper reinforcement reserved section 3-1 one by one;

[0034] S3: hoisting the prepared upper prefabricated component 1 above the groove portion of the lower prefabricated component 2, connecting the upper reinforcement reserved section 3-1 and the connecting reinforcement reserved section 4-1 through the reinforcement connector 5, so as to connect the longitudinal reinforcement 3 and the connecting reinforcement 4 as a whole, and at this time, the non-bonded section 8 is located above the reinforcement connector 5;

[0035] S4: Tie multiple circles of the closed stirrups 7 around the upper reinforcement reserved section 3-1, then support the formwork around the raised part 1-2 of the upper prefabricated component 1 and the groove part of the lower prefabricated component 2 and pour the post-cast concrete 6, bury the upper reinforcement reserved section 3-1, the closed stirrups 7 and the reinforcement connector 5 together in the post-cast concrete 6, and cure the post-cast concrete 6 to form the upper prefabricated component 1 and the lower prefabricated component 2 as a whole.

[0036] The step S3 specifically includes the following contents:

[0037] S3-1: Install the bottom connecting sleeve 5-3 on the connecting rib reserved section 4-1, insert the supporting ring 5-4 into the annular groove 9 of the connecting rib reserved section 4-1, and insert the bottom groove 5-1-4 into the lower rib reserved section 4 until it is fixed in position;

[0038] S3-2: Screw the bottom connecting sleeve 5-3 upward into the bottom of the connector body 5-1 until the support ring 5-4 is tightly embedded in the connection rib reserved section 4-1 and the bottom end of the connector body 5-1, thereby fixing the connector body 5-1 on the connection rib reserved section 4-1;

[0039] S3-3: Install the top connection sleeve 5-2 on the upper reinforcement reserved section 3-1, insert the support ring 5-4 into the annular groove 9 of the upper reinforcement reserved section 3-1, hoist the upper prefabricated component 1 to the top of the groove part of the lower prefabricated component 2, make the upper reinforcement reserved section 3-1 correspond to the connection reinforcement reserved section 4-1 one by one, and insert the upper reinforcement reserved section 3-1 into the top groove 5-1-3 to a fixed position;

[0040] S3-4: Screw the top connecting sleeve 5-2 downward into the top of the connector body 5-1 until the support ring 5-4 is tightly embedded in the upper reinforcement reserved section 3-1 and the top end of the connector body 5-1, thereby completing the fastening connection between the longitudinal reinforcement 3 and the connecting reinforcement 4.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The structural form proposed by the present invention inserts the bottom part of the pier with the embedded connector into the lower prefabricated component, which can realize the downward shift of the joint and rigid section of the prefabricated pier, making this type of prefabricated pier closer to the same as the cast-in-place structure, and avoiding the problem that the ductility of the pier body cannot be fully exerted due to the strain concentration and severe deformation at the joint of the traditional prefabricated pier under the action of seismic load. The cross-sectional area of ​​the raised part of the upper prefabricated component is set to be smaller than its original cross-sectional area. On the one hand, the longitudinal reinforcement can be exposed, thereby facilitating the construction of the reinforcement connector at the installation site. On the other hand, the post-cast concrete can include both a part of the upper prefabricated component and a part of the lower prefabricated component. Compared with the traditional method of inserting the bottom of the upper prefabricated component into the lower prefabricated component and only setting concrete in the lower prefabricated component, this can make the prefabricated assembly structure have better integrity at the connection, can solve the problem that the prefabricated structure is prone to serious damage at the connection or the bottom of the pier under the action of seismic load, and enable the structure to fully exert its ductility. At the same time, since there is a bonding interface between the post-cast concrete and the already cast concrete, which is another weak point in the structure, the present invention makes the bottom opening of the groove part of the lower prefabricated component larger than the top opening, and the cross-section is trapezoidal. On the basis of relying on the bonding interface between the post-cast concrete and the already cast concrete to resist the load, the resistance provided by the structural form and the excellent mechanical properties of the high-performance material itself can be added to further improve the bearing capacity of the structure at the post-cast concrete.

[0043] (2) The present invention replaces part of the longitudinal reinforcement in the prefabricated bridge pier with reinforcement made of shape memory alloy (SMA), and utilizes the excellent deformation recovery ability of SMA reinforcement to solve the technical problem of excessive residual displacement and insufficient recovery force of the bridge pier under the action of earthquake load. The post-cast fiber reinforced concrete (such as ultra-high performance concrete (UHPC) or shape memory fiber concrete) and SMA reinforcement at the bottom of the pier jointly bear the horizontal cyclic load, which can overcome the problem of poor energy dissipation capacity caused by the use of SMA reinforcement alone. The structural form proposed by the present invention can significantly and effectively reduce the residual displacement of the structure without reducing the energy dissipation capacity of the prefabricated bridge pier, and achieves the technical effect of obtaining a structural form that is better than cast-in-place piers in the field of assembly.

[0044] (3) The connector proposed by the present invention can generate sufficient extrusion force in its main body to ensure the connection performance of the reinforcement in the connector. The end of the connector main body is enlarged and cooperates with the wedge-shaped support ring. The support ring is embedded and transmits force with the reinforcement through protrusions and grooves. The provision of a number of gaps at the end of the connector main body can ensure that the prefabricated segment with reserved reinforcement has sufficient error margin during installation. In the process of screwing the top connecting sleeve and the bottom connecting sleeve together, the top and bottom ends of the connector main body with the gap can be tightened inward to increase its clamping force on the reinforcement. At the same time, the screwed top connecting sleeve and the bottom connecting sleeve will also exert pressure on the support ring. By utilizing the wedge shape of the support ring, the support ring and the reinforcement embedded therewith are continuously anchored in the top groove and the bottom groove of the connector main body under this pressure, and finally a tight connection between the reserved reinforcement and the top of the connector main body is achieved. When connecting the reserved reinforcements of adjacent prefabricated components, the deadweight of the hoisted upper prefabricated component can be used to provide the force to insert its reserved reinforcements into the connector. The construction is convenient and fast, and can greatly improve the construction efficiency while ensuring excellent connection performance.

[0045] (4) Anchorage length L given by the present invention an The formulas that need to be satisfied, the formulas that need to be satisfied by the length of the protruding part of the upper prefabricated component, and the calculation formulas for the top and bottom opening widths of the groove part of the lower prefabricated component are analyzed through the laws obtained by mechanical principle calculation and finite element parameter expansion calculation, providing better parameter selection and guiding engineering design and application.

[0046] To sum up, the connector proposed in the present invention can generate sufficient extrusion force to ensure the connection performance of the reinforcement in the connector. The end of the connector body is enlarged and cooperates with the wedge-shaped support ring. The support ring is embedded and transmits force with the reinforcement through protrusions and grooves, which can make the prefabricated assembly structure have better integrity at the connection, solve the problem that the prefabricated structure is prone to serious damage at the connection or pier bottom under seismic load, and enable the structure to give full play to its ductile performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of the prefabricated and assembled bridge pier structure.

[0048] Figure 2 It is a schematic diagram of the specific structure of the reinforcing bar connector 5.

[0049] Figure 3 It is a schematic diagram of the structure of the connector body 5-1.

[0050] Figure 4 It is a schematic diagram of the structure of the support ring 5-4 in the connector body.

[0051] Figure 5(a)-(d) in the figure are schematic diagrams of the process flow of prefabricated and assembled bridge piers.

[0052] Figure 6 is the stress cloud diagram of the connector finite element analysis under different groove depths, where Figure 6 (a) is a connector with a groove depth of 1 mm; (b) is a connector with a groove depth of 2 mm.

[0053] Figure 7 Comparison of simulated values ​​of stress-strain curves of connectors at different groove depths.

[0054] Figure 8 This is the stress cloud diagram of the connector finite element analysis under different groove types, where Figure 8 (a) is a connector with a ring groove as the groove type; (b) is a connector with a half groove as the groove type.

[0055] Fig. 9 It is a comparison chart of the simulated values ​​of the stress-strain relationship curve of the connector under different groove types.

[0056] Fig.10 It is a schematic diagram of the results of the axial pull-out test of the connector and the corresponding pull-out test of the steel bar raw material.

[0057] Fig.11 See the figure for comparison between the connector stress-strain curve and the test value.

[0058] In the figure: 1. Upper prefabricated component; 1-2. Raised part; 2. Lower prefabricated component; 3. Longitudinal reinforcement; 3-1. Reserved section of upper reinforcement; 4. Connecting reinforcement; 5. Rebar connector; 5-1. Connector body; 5-2. Top connecting sleeve; 5-3. Bottom connecting sleeve; 5-4. Support ring; 5-1-1. Internal limiting protrusion; 5-1-2. External limiting protrusion; 5-1-3. Top groove; 5-1-4. Axial slit; 5-1-5 Bottom groove; 5-4-1. Axial groove; 5-4-2. Support ring protrusion; 5-4-3. Disconnected gap 6. Post-cast concrete; 7. Closed stirrups; 8. Unbonded section; 9. Annular groove. DETAILED DESCRIPTION

[0059] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0060] like Figure 1As shown, a prefabricated assembled bridge pier suitable for high-intensity earthquake areas includes an upper prefabricated component 1 and a lower prefabricated component 2, wherein a plurality of longitudinal bars 3 are arranged inside the upper prefabricated component 1, and a plurality of connecting bars 4 are arranged inside the lower prefabricated component 2. A convex portion 1-2 is arranged at the bottom of the upper prefabricated component 1, and the cross-sectional area of ​​the convex portion 1-2 is smaller than the original cross-sectional area of ​​the upper prefabricated component 1. The longitudinal bars 3 extend out of an upper bar material reserved section 3-1 along the convex direction, and the upper bar material reserved section 3-1 is located in an area outside the convex portion. A groove portion is arranged at the top of the lower prefabricated component 2, and the bottom opening of the groove portion is larger than the top opening, and the cross-section is trapezoidal; the connecting bars 4 extend out of the connecting bars 4 at the top surface of the groove portion. A reinforcement reserved section 4-1, the connection reinforcement reserved section 4-1 corresponds to the upper reinforcement reserved section 3-1 one by one; the raised portion of the upper prefabricated component 1 is inserted into the groove portion of the lower prefabricated component 2, the connection reinforcement reserved section 4-1 is connected to the upper reinforcement reserved section 3-1 through a reinforcement connector 5, a non-bonded section 8 is provided on the upper reinforcement reserved section 3-1, and the non-bonded section 8 is located above the reinforcement connector 5, and multiple layers of closed stirrups 7 are arranged on the periphery of the upper reinforcement reserved section 3-1, and post-cast concrete 6 is arranged on the periphery of the raised portion of the upper prefabricated component 1 and the groove portion of the lower prefabricated component 2, so that the upper prefabricated component 1 and the lower prefabricated component 2 form a whole.

[0061] like Figure 2 As shown, the reinforcement connector 5 is composed of a connector body 5-1, a top connecting sleeve 5-2, a bottom connecting sleeve 5-3 and a support ring 5-4. The middle part of the connector body 5-1 is provided with an internal limiting protrusion 5-1-1 and an external limiting protrusion 5-1-2 inwardly and outwardly respectively. The top and bottom of the connector body 5-1 are provided with a top groove 5-1-3 and a bottom groove 5-1-4 respectively. The upper reinforcement reserved section 3-1 is inserted into the top groove 5-1-3 for anchoring, and the connecting reinforcement reserved section 4-1 is inserted into the bottom groove 5-1-4 for anchoring; the top connecting sleeve 5-2 and the bottom connecting sleeve 5-3 both include a large diameter The large diameter end is provided with an internal thread, and the top and bottom of the connector body 5-1 are provided with external threads, so that the large diameter end of the top connecting sleeve 5-2 and the top of the connector body 5-1, and the large diameter end of the bottom connecting sleeve 5-3 and the bottom of the connector body 5-1 are connected by threads; the inner diameter of the small diameter end is adapted to the outer diameter of the upper reinforcement reserved section 3-1 and the connecting reinforcement reserved section 4-1, and the top groove 5-1-3 and the upper reinforcement reserved section 3-1, as well as the bottom groove 5-1-4 and the connecting reinforcement reserved section 4-1 are in close contact through the support ring 5-4.

[0062] like Figure 3 and Figure 4 As shown, the top and bottom of the connector body 5-1 are provided with a plurality of non-through axial slits 5-1-5, the inner surface of the top end head and the inner surface of the bottom end head of the connector body 5-1 are both outwardly expanded, the support ring 5-4 is in the shape of a hollow inverted frustum, and the outer surface of the support ring 5-4 is adapted to the inner surface of the top end head and the inner surface of the bottom end head of the connector body 5-1; the surfaces of the upper rib reserved section 3-1 and the connecting rib reserved section 4-1 are both provided with annular grooves 9, and the inner surface of the support ring 5-4 is provided with a groove that matches the annular grooves The support ring protrusion 5-4-2 matches the groove 9, and the support ring 5-4 is embedded between the annular groove of the upper reinforcement reserved section 3-1 and the top end of the connector body 5-1, and between the annular groove of the connecting reinforcement reserved section 4-1 and the bottom end of the connector body 5-1. The outer surface of the support ring 5-4 is provided with an axial groove 5-4-1, the depth of the axial groove 5-4-1 is less than the thickness of the support ring 5-4, and the support ring 5-4 is provided with a disconnection gap 5-4-3 opposite to the axial groove 5-4-1.

[0063] like Figure 1-4 As shown, the anchoring length L of the upper reinforcement reserved section 3-1 and the connecting reinforcement reserved section 4-1 in the reinforcement connector 5 is an Need to meet:

[0064]

[0065] in,

[0066] A t =0.785(d-0.94P) 2

[0067] E s,min =d-0.65P

[0068] K n,max =d-1.08P

[0069] In the formula, L an is the anchorage length, d is the bar diameter, and P is the thread pitch; A t is the equivalent area corresponding to the pitch diameter of the thread, E s,min is the elastic modulus of the thread material, K n,max The thread diameter.

[0070] The depth of the top groove 5-1-3 and the bottom groove is greater than the anchoring length L an .

[0071] The calculation formula for the length of the raised portion of the upper prefabricated component is:

[0072]

[0073] Among them, l is the side length or diameter of the pier cross section, and h is the pier height.

[0074] The calculation formula for the top opening width of the groove portion of the lower prefabricated component 2 is:

[0075]

[0076] The calculation formula for the bottom opening width of the groove portion of the lower prefabricated component 2 is:

[0077] B b =0.575B u +3.925

[0078] Among them, since the upper prefabricated component 1 is a ductile component, it will produce ductile damage in a certain area at the bottom under the action of seismic load. This part of the area prone to damage is loaded with high-performance concrete to improve the seismic performance of the structure. L0 is calculated based on the area where damage may occur. The bottom opening width of the groove part of the lower prefabricated component 2 must be greater than the top opening width of the groove part of the lower prefabricated component 2. The shape and size of the tongue and groove formed must ensure that the structure is damaged at the bottom of the upper prefabricated component 1 when subjected to seismic loads, rather than on the lower prefabricated component 2.

[0079] See also Fig.10 By comparing the results of the axial pull-out test of the connector and the corresponding steel bar pull-out test, it can be seen that in terms of strength, the yield strength of the connector is slightly higher than that of the steel bar parent material, and the ultimate strength is equivalent to that of the steel bar parent material; in terms of deformation, since the parts in the connector are in dry contact, there are gaps. In the early stage of stretching, oscillations occur among the parts to eliminate the gaps and automatically integrate, which also leads to the slip of the connector in the early stage of stretching being greater than that of the steel bar parent material; the deformation generated by the connector after entering plasticity is less than that of the steel bar parent material, and the ductility is slightly inferior to that of the steel bar parent material.

[0080] Comparison of the stress-strain relationship curve of the connector calculated according to the theoretical formula and the test value can be found in Fig.11 In the elastic stage, the theoretical formula does not take into account the displacement caused by the gaps between the connector parts, resulting in the elastic stiffness in the theoretical results being higher than the test value, and the total displacement being smaller than the test value, and the error value being acceptable. Overall, it can be seen that the theoretical model proposed in this application fits the test value well.

[0081] like Figure 1-4As shown, the depth of the top groove 5-1-3 is greater than the anchorage length of the upper reinforcement reserved section 3-1, and the depth of the bottom groove 5-1-4 is greater than the anchorage length of the connection reinforcement reserved section 4-1. The longitudinal reinforcements 3, which account for 20% and are not less than 2, and the corresponding connection reinforcements 4 are made of shape memory alloy materials, and the post-cast concrete 6 is made of ultra-high performance concrete or shape memory alloy fiber concrete.

[0082] In order to explore the optimal parameters, finite element calculation and analysis were carried out for different groove depths and different groove types for 12 mm diameter HRB400 steel bars and 16 mm diameter HRB400 steel bars, such as Figure 6 , Figure 7 , Figure 8 and Fig. 9 As shown. The results show that the connector failure occurs on the steel bar and is located outside the groove. This is because the clamping force generated by the support ring on the groove part of the steel bar can compensate for the weakening effect of the steel bar caused by the groove. After calculation, it can be seen that the bearing capacity of the groove depth of 2mm is reduced by 11.5% compared with the groove depth of 1mm, and the displacement ductility capacity is reduced by 29.1%. Therefore, the steel bar groove depth parameter is preferably 1mm groove depth; the two groove forms of annular groove and half groove are calculated and analyzed. The results show that the bearing capacity and deformation capacity of the two are similar, and the half groove form is slightly better than the annular groove form. Specifically, the bearing capacity of the connector with the half groove form is increased by 11.1% compared with the connector with the annular groove form, and the displacement ductility capacity is increased by 15.2%. Therefore, the steel bar groove form parameter is preferably the half groove form.

[0083] like Figure 5 (a) Figure 5 (b) Figure 5 (c) and Figure 5 As shown in (d), a prefabricated and assembled bridge pier construction method suitable for high-intensity earthquake areas is provided, comprising the following steps:

[0084] S1: tying the steel cage of the upper prefabricated component 1 and installing the formwork, pouring concrete, and preparing the upper prefabricated component 1. At this time, the longitudinal reinforcement 3 extends out of the upper reinforcement reserved section 3-1 along the convex direction of the convex part of the upper prefabricated component 1, and the non-bonded section 8 is arranged on the upper reinforcement reserved section 3-1;

[0085] S2: Tie the steel cage of the lower prefabricated component 2 and install the formwork, pour concrete, and prepare the lower prefabricated component 2. At this time, the connecting bar 4 extends out of the connecting bar reserved section 4-1 on the top surface of the groove part of the lower prefabricated component 2, corresponding to the upper reinforcement reserved section 3-1 one by one;

[0086] S3: hoisting the prepared upper prefabricated component 1 above the groove portion of the lower prefabricated component 2, connecting the upper reinforcement reserved section 3-1 and the connecting reinforcement reserved section 4-1 through the reinforcement connector 5, so as to connect the longitudinal reinforcement 3 and the connecting reinforcement 4 as a whole, and at this time, the unbonded section 8 is located above the reinforcement connector 5;

[0087] S4: Tie multiple circles of the closed stirrups 7 around the outer periphery of the upper reinforcement reserved section 3-1, then support the formwork around the raised part of the upper prefabricated component 1 and the groove part of the lower prefabricated component 2 and pour the post-cast concrete 6, bury the upper reinforcement reserved section 3-1, the closed stirrups 7 and the reinforcement connector 5 together therein, and cure the post-cast concrete 6 to form the upper prefabricated component 1 and the lower prefabricated component 2 as a whole.

[0088] Wherein, step S3 specifically includes the following contents:

[0089] S3-1: Install the bottom connecting sleeve 5-3 on the connecting rib reserved section 4-1, insert the supporting ring 5-4 into the annular groove of the connecting rib reserved section 4-1, and insert the bottom groove 5-1-4 on the lower rib reserved section 4 until it is fixed in position;

[0090] S3-2: Screw the bottom connecting sleeve 5-3 upward into the bottom of the connector body 5-1 until the support ring 5-4 is tightly embedded in the connection rib reserved section 4-1 and the bottom end of the connector body 5-1, thereby fixing the connector body 5-1 on the connection rib reserved section 4-1;

[0091] S3-3: Install the top connection sleeve 5-2 on the upper reinforcement reserved section 3-1, insert the support ring 5-4 into the annular groove of the upper reinforcement reserved section 3-1, hoist the upper prefabricated component 1 to the top of the groove portion of the lower prefabricated component 2, make the upper reinforcement reserved section 3-1 correspond to the connection reinforcement reserved section 4-1 one by one, and insert the upper reinforcement reserved section 3-1 into the top groove 5-1-3 to a fixed position;

[0092] S3-4: Screw the top connecting sleeve 5-2 downward into the top of the connector body 5-1 until the support ring 5-4 is tightly embedded in the upper reinforcement reserved section 3-1 and the top end of the connector body 5-1, thereby completing the fastening connection between the longitudinal reinforcement 3 and the connecting reinforcement 4.

[0093] In summary, the present invention avoids the problem that the ductility of the pier body cannot be fully exerted due to the strain concentration and severe deformation at the joints of the traditional prefabricated piers under the action of seismic loads. The pier bottom part with the buried connector is inserted into the lower prefabricated component, so that the joints and rigid sections of the prefabricated piers can be moved downward, making this type of prefabricated pier closer to the equivalent of cast-in-place structures, and can solve the problem that the prefabricated structure is prone to serious damage at the connection or the pier bottom under the action of seismic loads, and enable the structure to fully exert its ductility and bearing capacity at the post-poured concrete.

Claims

1. A prefabricated and assembled bridge pier suitable for use in areas with high seismic intensity, comprising an upper prefabricated component (1) and a lower prefabricated component (2), characterized in that: The upper prefabricated component (1) is provided with a plurality of longitudinal ribs (3) inside, and the lower prefabricated component (2) is provided with a plurality of connecting ribs (4) inside; A raised portion (1-2) is provided at the bottom of the upper prefabricated component (1), and the cross-sectional area of ​​the raised portion (1-2) is smaller than the original cross-sectional area of ​​the upper prefabricated component (1); the portion of the longitudinal reinforcement (3) extending in the raised direction is a reserved section (3-1) for upper reinforcement material, and the reserved section (3-1) for upper reinforcement material is located in an area outside the raised portion; The top of the lower prefabricated component (2) is provided with a groove portion, the bottom opening of the groove portion is larger than the top opening, and the cross section is trapezoidal; the portion of the connecting rib (4) extending from the top surface of the groove portion is a connecting rib reserved section (4-1), and the connecting rib reserved section (4-1) is connected to the upper rib reserved section (3-1) in a one-to-one correspondence; the raised portion of the upper prefabricated component (1) is inserted into the groove portion of the lower prefabricated component (2).

2. The prefabricated assembled bridge pier suitable for high-intensity earthquake zones according to claim 1, characterized in that: The upper reinforcement reserved section (3-1) and the connection reinforcement reserved section (4-1) are connected via a reinforcement connector (5). Specifically, a non-bonded section (8) is arranged above the connection between the end of the upper reinforcement reserved section (3-1) and the reinforcement connector 5, multiple layers of closed stirrups (7) are arranged around the upper reinforcement reserved section (3-1), and post-cast concrete (6) is arranged around the upper raised portion (1-2) and the groove portion of the lower prefabricated component (2), so that the upper prefabricated component (1) and the lower prefabricated component (2) form a whole.

3. The prefabricated assembled bridge pier suitable for use in high-intensity earthquake zones according to claim 2, characterized in that: The reinforcing bar connector (5) comprises a connector body (5-1), wherein an internal limiting protrusion (5-1-1) and an external limiting protrusion (5-1-2) are respectively arranged inwardly and outwardly in the middle of the connector body (5-1), and a top groove (5-1-3) and a bottom groove (5-1-4) are respectively arranged at the top and bottom of the connector body (5-1); the upper reinforcing bar reserved section (3-1) is inserted into the top groove (5-1-3) for anchoring, and the connecting bar reserved section (4-1) is inserted into the bottom groove (5-1-4) for anchoring; the top and bottom of the connector body (5-1) are respectively connected to the top connecting sleeve (5-2) and the bottom connecting sleeve (5-3) by threaded connection, and the top groove (5-1-3) and the upper reinforcing bar reserved section (3-1), and the bottom groove (5-1-4) and the connecting bar reserved section (4-1) are in close contact through the support ring (5-4).

4. The prefabricated assembled bridge pier suitable for high-intensity earthquake zones according to claim 3, characterized in that: The top connecting sleeve (5-2) and the bottom connecting sleeve (5-3) both comprise a large diameter end and a small diameter end, wherein the large diameter end is provided with an internal thread connected to the external threads at the top and bottom of the connector body (5-1); and the inner diameter of the small diameter end is adapted to the outer diameter of the upper rib reserved section (3-1) and the connecting rib reserved section (4-1).

5. The prefabricated assembled bridge pier suitable for high-intensity earthquake zones according to claim 3, characterized in that: The top and bottom of the connector body (5-1) are provided with a plurality of non-through axial slits (5-1-5); the inner surface of the top end and the inner surface of the bottom end of the connector body (5-1) are both outwardly expanded; the support ring (5-4) is in the shape of a hollow inverted truncated cone; the outer surface of the support ring (5-4) is adapted to the inner surface of the top end and the inner surface of the bottom end of the connector body (5-1); The surfaces of the upper reinforcement reserved section (3-1) and the connecting reinforcement reserved section (4-1) are both provided with an annular groove (9); the inner surface of the support ring (5-4) is provided with a support ring protrusion (5-4-2) matching the annular groove (9); the support ring protrusion (5-4-2) is embedded in the annular groove (9); the outer surface of the support ring (5-4) is provided with an axial groove (5-4-1); the depth of the axial groove (5-4-1) is less than the thickness of the support ring (5-4); and the support ring (5-4) is provided with a disconnection gap (5-4-3) opposite to the axial groove (5-4-1).

6. The prefabricated assembled bridge pier suitable for high-intensity earthquake zones according to claim 3, characterized in that: The anchoring length L of the upper reinforcement reserved section (3-1) and the connection reinforcement reserved section (4-1) in the reinforcement connector (5) is an Need to meet: in, A t =0.785(d-0.94P) 2 AND s,min =d-0.65P K n,max =d-1.08P Where, L an is the anchorage length, d is the bar diameter, and P is the thread pitch; A t is the equivalent area corresponding to the thread diameter, E s,min is the elastic modulus of the thread material, K n,max is the thread diameter; The depth of the top groove (5-1-3) and the bottom groove is greater than the anchoring length L an .

7. The prefabricated assembled bridge pier suitable for high-intensity earthquake zones according to claim 1, characterized in that: The length of the raised portion (1-2) of the upper prefabricated component (1) must satisfy: Where l is the side length or diameter of the pier cross section, and h is the pier height; The top opening width of the groove portion of the lower prefabricated component (2) must meet the following requirements: The calculation formula for the bottom opening width of the groove portion of the lower prefabricated component (2) is: B b =0.575B u +3.925。 8. The prefabricated bridge pier suitable for use in areas with high earthquake intensity according to claim 1, characterized in that: The longitudinal reinforcement (3) and the corresponding connecting reinforcement (4), accounting for more than 20% and not less than 2, are made of shape memory alloy material; the post-cast concrete (6) is made of ultra-high performance concrete or shape memory alloy fiber concrete.

9. A method for constructing prefabricated bridge piers suitable for areas with high earthquake intensity, characterized in that: The following steps are involved: S1: tying the steel cage of the upper prefabricated component (1) and installing the formwork, pouring concrete, and preparing the upper prefabricated component (1). At this time, the longitudinal reinforcement (3) extends out of the upper reinforcement reserved section (3-1) along the convex direction of the convex part (1-2) of the upper prefabricated component (1), and a non-bonded section (8) is provided on the upper reinforcement reserved section (3-1); S2: Tie up the steel cage of the lower prefabricated component (2) and install the formwork, pour concrete, and prepare the lower prefabricated component (2). At this time, the connecting bar (4) extends out of the reserved section (4-1) of the connecting bar on the top surface of the groove part of the lower prefabricated component, corresponding to the reserved section (3-1) of the upper reinforcement material one by one; S3: hoisting the prepared upper prefabricated component (1) above the groove portion of the lower prefabricated component (2), connecting the upper reinforcement reserved section (3-1) and the connecting reinforcement reserved section (4-1) through a reinforcement connector (5), thereby connecting the longitudinal reinforcement (3) and the connecting reinforcement (4) as a whole, and at this time, the non-bonded section (8) is located above the reinforcement connector (5); S4: a plurality of circles of the closed stirrups (7) are tied around the outer periphery of the upper reinforcement reserved section (3-1), and then a formwork is supported around the outer periphery of the raised portion (1-2) of the upper prefabricated component (1) and the recessed portion of the lower prefabricated component (2) and the post-cast concrete (6) is poured, the upper reinforcement reserved section (3-1), the closed stirrups (7) and the reinforcement connector (5) are buried together in the post-cast concrete (6), and the post-cast concrete (6) is cured, so that the upper prefabricated component (1) and the lower prefabricated component (2) form a whole.

10. A method for constructing prefabricated bridge piers suitable for high-intensity earthquake zones according to claim 9, characterized in that: The step S3 specifically includes the following contents: S3-1: Install the bottom connection sleeve (5-3) on the connection reinforcement reserved section (4-1), insert the support ring (5-4) into the annular groove (9) of the connection reinforcement reserved section (4-1), and insert the bottom groove (5-1-4) on the lower reinforcement reserved section (4) until it is fixed in position; S3-2: screwing the bottom connecting sleeve (5-3) upwards into the bottom of the connector body (5-1) until the supporting ring (5-4) is tightly embedded in the connection rib reserved section (4-1) and the bottom end of the connector body (5-1), thereby fixing the connector body (5-1) on the connection rib reserved section (4-1); S3-3: Install the top connection sleeve (5-2) on the upper reinforcement reserved section (3-1), insert the support ring (5-4) into the annular groove (9) of the upper reinforcement reserved section (3-1), hoist the upper prefabricated component (1) above the groove portion of the lower prefabricated component (2), make the upper reinforcement reserved section (3-1) correspond to the connection reinforcement reserved section (4-1) one by one, and insert the upper reinforcement reserved section (3-1) into the top groove (5-1-3) to a fixed position; S3-4: Screw the top connecting sleeve (5-2) downward into the top of the connector body (5-1) until the support ring (5-4) is tightly embedded in the upper reinforcement reserved section (3-1) and the top end of the connector body (5-1), thereby completing the fastening connection between the longitudinal reinforcement (3) and the connecting reinforcement (4).

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