Fabricated building frame structure beam-column joint structure and implementation method

Abstract

The invention relates to the field of fabricated buildings, in particular to a fabricated building frame structure beam-column joint structure and an implementation method, and the beam-column joint structure comprises a reinforced concrete prefabricated column and a reinforced concrete prefabricated beam. A column cap is arranged on the top of the lower-layer column, a prefabricated column reserved anchoring longitudinal bar on the column penetrates through the column cap and is connected with an upper-layer column longitudinal bar anchoring hole, and a grouting hole and an exhaust hole are formed in the side face of the upper-layer column. One end of the precast beam is lapped on the column cap, a horizontal anchoring rib is reserved on the lower portion of the beam and extends to the joint, a precast beam stirrup is exposed out of the top, secondary cast-in-place concrete is laid on the top, a formwork is connected to the side face, a reserved groove is formed in the joint side, and a bed mortar layer is arranged at the bottom of the upper-layer column. According to the structure, the bearing and shearing resistance of beam-column joints is enhanced, and the stability and shock resistance of the frame are improved; prefabricated parts are produced in factories, efficiently assembled on site, matched with standard construction procedures, shortened in construction period and matched with industrial production, development of fabricated buildings is effectively promoted, and the problems of node connection and construction efficiency of existing fabricated structures are solved.

Description

Technical Field

[0001] The present invention relates to the field of prefabricated buildings, and in particular to a beam-column node structure of a prefabricated building frame and an implementation method thereof. Background Art

[0002] In traditional construction, cast-in-place concrete structures are often used to construct beam-column joints. On-site formwork, steel bar binding, and concrete pouring are complicated processes that require a lot of manpower and time, resulting in a lengthy construction period. For example, in large-scale construction projects, the construction of beam-column joints often consumes a large proportion of the overall construction period, seriously affecting the progress of the project. The components of existing prefabricated concrete structures are prefabricated in factories and hoisted, spliced, and installed at the construction site. The splicing nodes of beams, slabs, columns, and other components become their weak points in terms of force. The connection method and construction characteristics of the nodes not only affect the overall force performance of the structure but also affect production efficiency.

[0003] Therefore, it is necessary to propose a beam-column node construction and implementation method for an assembled building frame structure to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a beam-column node structure and an implementation method for an assembled building frame structure, so as to solve the problem that the connection mode and construction characteristics of the nodes not only affect the overall stress performance of the structure but also affect the production efficiency.

[0005] To achieve the above object, the present invention provides the following technical solutions: A prefabricated building frame structure beam-column node structure, comprising a prefabricated reinforced concrete column and a prefabricated reinforced concrete beam, wherein the prefabricated reinforced concrete column comprises a lower prefabricated reinforced concrete column and an upper prefabricated reinforced concrete column, wherein the top of the lower prefabricated reinforced concrete column is connected with a column cap, one end of the prefabricated reinforced concrete beam is overlapped on the top of the column cap, the lower prefabricated reinforced concrete column is connected with a plurality of prefabricated column reserved anchor longitudinal bars, the prefabricated column reserved anchor longitudinal bars pass through the column cap, a longitudinal bar anchor hole is arranged in the lower part of the column shaft of the upper prefabricated reinforced concrete column, one end of the prefabricated column reserved anchor longitudinal bars is connected to the inside of the longitudinal bar anchor hole, and the upper prefabricated reinforced concrete column is connected with a column cap. A plurality of grouting holes are arranged on the side of the reinforced concrete precast column near the bottom, and the grouting holes are connected with the longitudinal reinforcement anchor holes. A plurality of exhaust holes are arranged on the side of the upper reinforced concrete precast column near the top, and the exhaust holes are connected with the longitudinal reinforcement anchor holes. A plurality of lower reserved horizontal anchor bars are arranged on the reinforced concrete precast beam, and one end of the lower reserved horizontal anchor bar extends to the beam-column node. A plurality of precast beam stirrups are arranged on the reinforced concrete precast beam. Secondary cast-in-place concrete is laid on the top of the reinforced concrete precast beam. A formwork is fixedly connected to the side of the reinforced concrete precast beam, and a retention groove is arranged on one side of the beam-column node of the reinforced concrete precast beam.

[0006] Preferably, the tops of the plurality of precast beam stirrups are exposed from the upper surface of the reinforced concrete precast beam, and the secondary cast-in-place concrete covers the precast beam stirrups.

[0007] Preferably, the lower reserved horizontal anchoring bars are tightly fitted with the precast column reserved longitudinal anchoring bars, and the plurality of reinforced concrete precast beams and precast beam stirrups are welded and connected to each other through steel bars.

[0008] Preferably, a mortar layer is provided at the bottom connection position of the upper reinforced concrete prefabricated column.

[0009] Preferably, the template is fixed on the reinforced concrete precast beam by bolts.

[0010] Preferably, the column cross-sectional dimensions of the lower layer precast reinforced concrete columns and the upper layer precast reinforced concrete columns are 700mm×700mm, the cross-sectional dimensions of the column caps are 1260mm×1260mm, the beam cross-sectional dimensions of the precast reinforced concrete beams are 500mm×1050mm, and the beam cross-sectional dimensions of the precast reinforced concrete beams paved with secondary cast-in-place concrete are 500mm×1200mm.

[0011] Preferably, a method for implementing a beam-column node of an assembled building frame structure comprises the following steps: S1: Set a hoisting point on the top of the lower reinforced concrete precast column, use a level ruler to accurately place the lower reinforced concrete precast column on the positioning line, insert the reserved anchor longitudinal reinforcement of the precast column into the longitudinal reinforcement anchor hole for temporary fixation, and use special grouting material for grouting construction. After 24 hours, the grouting process is carried out after the grouting reaches a certain strength. After all grouting holes and exhaust holes overflow, the pressure is maintained for 30 seconds; S2: Mark the column cap and lay out the positioning line of the reinforced concrete precast beam on the column cap. After the reinforced concrete precast beam is in place, the reserved horizontal anchor bars and bottom additional bars of the reinforced concrete precast beam are closely fitted with the reserved anchor longitudinal bars of the precast column; S3: Use reinforced concrete truss floor decking, cut and lay the material according to the size between the reinforced concrete precast beams, install the beam surface steel bars that have been prepared in advance into the upper longitudinal bars of the beams according to the design drawings and specifications, tie the floor slab steel bottom bars at the trough of the reinforced concrete truss floor decking, use cement pads and short steel bars to control the thickness of the floor decking bottom bar protection layer and the bottom bar position, tie the floor slab surface bars and additional bars according to the wave height and wave distance, and use horse stools to control the height of the floor slab surface bars; S4: Before pouring the floor, re-measure the elevation control steel bar elevation and the bottom elevation of the steel decking of all slabs in the pouring area to ensure that the thickness of the poured floor meets the design requirements, and re-check the thickness of the floor steel bar protective layer. When pouring, use a vibrating rod to vibrate it thoroughly.

[0012] Technical effects and advantages of the present invention: 1. The connection between reinforced concrete precast beams and columns is firm, the column caps disperse the load at the beam ends, the reserved horizontal anchor bars at the bottom fit closely with the column longitudinal bars, increasing the connection and anchoring force, efficiently transmitting the shear force and bending moment at the beam ends, enhancing the bearing and shear resistance of the beam-column nodes, optimizing the structural stress, improving the frame stability, and meeting the functional requirements of the building.

[0013] 2. Prefabricated components are produced in factories, and on-site assembly reduces wet work, reduces the impact of human factors, and ensures component accuracy and quality. Column caps assist in the positioning of prefabricated beams to improve installation efficiency and accuracy. The grouting holes, vents, and seat grouting layers are scientifically designed. The seat grouting is filled and leveled, the grouting is densely connected, and the vents ensure the grouting quality, effectively avoiding defects in the connection parts, ensuring construction quality, and reducing safety hazards.

[0014] 3. Prefabricated construction simplifies the process, prefabricated columns and beams are quickly installed, steel truss floor decks are conveniently laid, and steel bars are efficiently tied. Each link is closely connected and advanced in an orderly manner, which significantly shortens the construction period, saves manpower and time costs, speeds up the project progress, and improves economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention is a schematic diagram of the structural structure of a beam-column node of an assembled building frame structure.

[0016] Figure 2 It is a schematic diagram of the internal structure of the beam-column node of the present invention.

[0017] Figure 3 It is a schematic diagram of the structure of the retention groove position of the present invention.

[0018] Figure 4 It is a schematic diagram of the cross-sectional structure of the beam-column node of the present invention.

[0019] Figure 5 It is a schematic diagram of the longitudinal reinforcement anchor hole structure of the present invention.

[0020] In the figure: 1. Lower layer reinforced concrete precast columns; 2. Upper layer reinforced concrete precast columns; 3. Reinforced concrete precast beams; 4. Column caps; 5. Precast column reserved longitudinal anchor bars; 6. Longitudinal reinforcement anchor holes; 7. Lower reserved horizontal anchor bars; 8. Precast beam stirrups; 9. Secondary cast-in-place concrete; 10. Formwork; 11. Grouting holes; 12. Exhaust holes; 13. Seat mortar layer; 14. Retaining grooves. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The present invention provides Figure 1-Figure 5 The beam-column node structure of an assembled building frame structure shown in the figure includes a reinforced concrete precast column and a reinforced concrete precast beam 3, and there are multiple reinforced concrete precast beams 3, the reinforced concrete precast column includes a lower reinforced concrete precast column 1 and an upper reinforced concrete precast column 2, the top of the lower reinforced concrete precast column 1 is connected with a column cap 4, one end of the reinforced concrete precast beam 3 is overlapped on the top of the column cap 4, a plurality of precast column reserved anchor longitudinal bars 5 are connected to the lower reinforced concrete precast column 1, the precast column reserved anchor longitudinal bars 5 pass through the column cap 4, and a longitudinal bar anchor hole 6 is arranged in the lower part of the column body of the upper reinforced concrete precast column 2; See also Figure 1-2 As shown in Figure 5, the lower layer reinforced concrete precast column 1 is connected to the upper layer reinforced concrete precast column 2 through the longitudinal reinforcement anchor hole 6 and the reserved longitudinal reinforcement 5 of the precast column, and the upper and lower columns are formed into a stable whole through the grouting process. Under the action of vertical load, gravity is reliably transmitted to maintain the vertical stability of the structure; when horizontal load acts, the relative displacement between columns is limited and the overall anti-lateral displacement capacity is enhanced, such as effectively resisting shaking in an earthquake, preventing node damage from causing structural collapse, improving the seismic performance of the building, and ensuring safety; One end of the reinforced concrete precast beam 3 is overlapped on the column cap 4 of the lower reinforced concrete precast column 1, and the column cap disperses the load at the beam end and reduces the local compressive stress. The reserved horizontal anchor bar 7 at the bottom of the beam is closely fitted with the reserved anchor longitudinal bar 5 of the precast column, which increases the connection area and anchoring force, effectively transmits the shear force and bending moment at the beam end, enhances the bearing capacity and shear resistance of the beam-column node, ensures reasonable structural force, improves the stability of the frame structure, and meets the requirements of building use; One end of the reserved anchoring longitudinal reinforcement 5 of the precast column is connected to the inside of the longitudinal reinforcement anchor hole 6, a plurality of grouting holes 11 are arranged near the bottom of the side of the upper reinforced concrete precast column 2, and the grouting holes 11 are connected to the longitudinal reinforcement anchor hole 6, and a plurality of exhaust holes 12 are arranged near the top of the side of the upper reinforced concrete precast column 2, and the exhaust holes 12 are connected to the longitudinal reinforcement anchor hole 6; Prefabricated components are produced in the factory and assembled on site, reducing the amount of wet work on site. The column cap 4 provides a positioning reference for the hoisting of the prefabricated beam 3, which facilitates quick and accurate installation and improves construction efficiency. The design of the grouting hole 11, the exhaust hole 12 and the seat grout layer ensures the construction quality of the connection parts, reduces the difficulty of construction, reduces errors and safety hazards, conforms to the concept of efficient construction of prefabricated buildings, and promotes the process of building industrialization.

[0023] A plurality of lower reserved horizontal anchor bars 7 are arranged on the reinforced concrete precast beam 3, one end of which extends to the beam-column node, a plurality of precast beam stirrups 8 are arranged on the reinforced concrete precast beam 3, the tops of the plurality of precast beam stirrups 8 are exposed from the upper surface of the reinforced concrete precast beam 3, and secondary cast-in-place concrete 9 covers the precast beam stirrups 8; The lower reserved horizontal anchoring bar 7 is closely fitted with the precast column reserved anchoring longitudinal bar 5, and the multiple reinforced concrete precast beams 3 and the precast beam stirrups 8 are welded and connected to each other through steel bars; See also Figure 1-3 As shown, the lower reserved horizontal anchor bar 7 on the reinforced concrete precast beam 3 extends to the beam-column node and fits tightly with the column structure, significantly increasing the connection area and anchoring force between the beam and the column at the node. When the structure is subjected to stress, the shear force and bending moment at the beam end are effectively transmitted, greatly enhancing the bearing capacity and shear resistance of the beam-column node. Ensuring the coordinated work of the beam and the column and maintaining the stability of the structure are key factors in ensuring the safety of the overall structure. In addition, multiple precast beam stirrups 8 effectively constrain the longitudinal reinforcement in the beam to prevent the longitudinal reinforcement from lateral displacement when subjected to stress, thereby greatly improving the shear resistance of the reinforced concrete precast beam 3. When the beam is subjected to the shear force generated by vertical and horizontal loads, the stirrups can limit the cracking and crushing of the concrete, maintain the integrity and bearing capacity of the beam, and ensure that the beam plays a normal role in the structural system; The top of the precast beam stirrup 8 is exposed on the upper surface of the beam. In the subsequent construction, it is connected and tied with other steel bars at the node to further fix the position of the steel bars in the beam and ensure the stability of the steel bars at the node. This is conducive to maintaining the integrity of the steel skeleton during concrete pouring, enhancing the construction quality and structural reliability of the node, promoting the formation of a stable connection between beams, columns and other components at the node, and improving the overall collaborative working performance of the structure; by covering the precast beam stirrup 8 and other steel bars with secondary cast-in-place concrete 9, a protective barrier is provided for the steel bars to prevent the steel bars from rusting when exposed to the air, extend the service life of the steel bars, and ensure the long-term durability of the structure. The alkaline environment of the concrete helps to maintain the passivation state of the steel bars, further enhance the durability and safety of the structure, and reduce the cost of later maintenance.

[0024] The top of the reinforced concrete precast beam 3 is paved with secondary cast-in-place concrete 9, the side of the reinforced concrete precast beam 3 is fixedly connected with a template 10, the template 10 is fixedly installed on the reinforced concrete precast beam 3 by bolts, a retaining groove 14 is provided on one side of the beam-column node of the reinforced concrete precast beam 3, and a seat mortar layer 13 is provided at the bottom connection position of the upper reinforced concrete precast column 2; The column cross-section size of the lower layer reinforced concrete precast column 1 and the upper layer reinforced concrete precast column 2 is 700mm×700mm, the cross-section size of the column cap 4 is 1260mm×1260mm, the cross-section size of the reinforced concrete precast beam 3 is 500mm×1050mm, and the cross-section size of the reinforced concrete precast beam 3 paved with secondary cast-in-place concrete 9 is 500mm×1200mm; See also Figure 1 , 2 As shown in Figure 4, the secondary cast-in-place concrete 9 laid on the top of the reinforced concrete precast beam 3 fills the gap between the beam and other components such as the floor slab, so that the beam and the floor slab and other components are closely combined to form a whole, effectively enhancing the spatial collaborative working ability of the structure. Under the action of horizontal load, it can better transfer and distribute the load, significantly improve the overall stiffness and stability of the building structure, and ensure the safety performance of the building under various working conditions; The template 10 is fixed on the prefabricated beam 3 by bolts. This installation method makes the installation and removal of the template very convenient, which is convenient for construction workers to pour concrete and use the template in the future. It not only improves the construction efficiency and reduces the construction cost, but also meets the requirements of industrialized construction of prefabricated buildings, which is conducive to promoting the development and application of prefabricated buildings; The retention groove 14 on the side of the beam-column node on the reinforced concrete precast beam 3 can be filled with concrete or other bonding materials in the subsequent construction. When the filling material solidifies, it forms a mechanical interlocking structure with the concrete of the beam and column, which increases the connection strength and bonding force between the beam and the column at the node, further improving the integrity and stability of the beam-column node. The mortar layer 13 set at the bottom connection position of the upper reinforced concrete precast column 2 plays a role of filling and leveling, so that the upper precast column can be tightly connected with the lower structure.

[0025] The present invention provides a method for implementing a beam-column node of an assembled building frame structure, comprising the following steps: S1: Set a hoisting point on the top of the lower reinforced concrete precast column, use a level ruler to accurately place the lower reinforced concrete precast column on the positioning line, insert the reserved anchor longitudinal reinforcement of the precast column into the longitudinal reinforcement anchor hole for temporary fixation, and use special grouting material for grouting construction. After 24 hours, the grouting process is carried out after the grouting reaches a certain strength. After all grouting holes and exhaust holes overflow, the pressure is maintained for 30 seconds; S2: Mark the column cap and lay out the positioning line of the reinforced concrete precast beam on the column cap. After the reinforced concrete precast beam is in place, the reserved horizontal anchor bars and bottom additional bars of the reinforced concrete precast beam are closely fitted with the reserved anchor longitudinal bars of the precast column; S3: Use reinforced concrete truss floor decking, cut and lay the material according to the size between the reinforced concrete precast beams, install the beam surface steel bars that have been prepared in advance into the upper longitudinal bars of the beams according to the design drawings and specifications, tie the floor slab steel bottom bars at the trough of the reinforced concrete truss floor decking, use cement pads and short steel bars to control the thickness of the floor decking bottom bar protection layer and the bottom bar position, tie the floor slab surface bars and additional bars according to the wave height and wave distance, and use horse stools to control the height of the floor slab surface bars; S4: Before pouring the floor, re-measure the elevation control steel bar elevation and the bottom elevation of the steel decking of all slabs in the pouring area to ensure that the thickness of the poured floor meets the design requirements, and re-check the thickness of the floor steel bar protective layer. When pouring, use a vibrating rod to vibrate it thoroughly.

[0026] The implementation method of the beam-column nodes of the prefabricated building frame structure has significant beneficial effects, including enhancing structural stability and seismic resistance, ensuring effective load transfer through precise installation and anchoring of prefabricated columns and beams; ensuring construction quality, and standardizing the operations of grouting, grouting and steel bar construction; improving construction efficiency, and prefabricated components reduce on-site work and have an orderly process; being highly adaptable to industrialized production, and standardization of each link promotes the transformation and upgrading of the construction industry, and effectively promotes the development and application of prefabricated buildings.

[0027] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A beam-column node structure of an assembled building frame structure, comprising a reinforced concrete prefabricated column and a reinforced concrete prefabricated beam (3), wherein there are a plurality of the reinforced concrete prefabricated beams (3), characterized in that: The reinforced concrete prefabricated column comprises a lower layer reinforced concrete prefabricated column (1) and an upper layer reinforced concrete prefabricated column (2), wherein the top of the lower layer reinforced concrete prefabricated column (1) is connected to a column cap (4), one end of the reinforced concrete prefabricated beam (3) is overlapped on the top of the column cap (4), a plurality of prefabricated column reserved anchoring longitudinal bars (5) are connected to the lower layer reinforced concrete prefabricated column (1), the prefabricated column reserved anchoring longitudinal bars (5) pass through the column cap (4), a longitudinal bar anchoring hole (6) is arranged in the lower part of the column body of the upper layer reinforced concrete prefabricated column (2), one end of the prefabricated column reserved anchoring longitudinal bars (5) is connected to the inside of the longitudinal bar anchoring hole (6), and a plurality of grouting holes (11) are arranged on the side surface of the upper layer reinforced concrete prefabricated column (2) near the bottom, the grouting holes (11) are arranged on the side surface of the upper layer reinforced concrete prefabricated column (2) near the bottom, and the grouting holes (11) are arranged on the side surface of the upper layer reinforced concrete prefabricated column (2) near the bottom. The hole (11) is connected to the longitudinal reinforcement anchor hole (6); a plurality of exhaust holes (12) are provided on the side of the upper reinforced concrete precast column (2) near the top; the exhaust holes (12) are connected to the longitudinal reinforcement anchor hole (6); a plurality of lower reserved horizontal anchor bars (7) are provided on the reinforced concrete precast beam (3); one end of the lower reserved horizontal anchor bar (7) extends to the beam-column node; a plurality of precast beam stirrups (8) are provided on the reinforced concrete precast beam (3); secondary cast-in-place concrete (9) is laid on the top of the reinforced concrete precast beam (3); a template (10) is fixedly connected to the side of the reinforced concrete precast beam (3); and a retention groove (14) is provided on one side of the reinforced concrete precast beam (3) located at the beam-column node.

2. The beam-column node structure of an assembled building frame structure according to claim 1, characterized in that: The tops of the plurality of precast beam stirrups (8) are exposed from the upper surface of the reinforced concrete precast beam (3), and the secondary cast-in-place concrete (9) covers the precast beam stirrups (8).

3. The beam-column node structure of the assembled building frame structure according to claim 1 is characterized in that: The lower reserved horizontal anchoring bars (7) are arranged in close contact with the precast column reserved anchoring longitudinal bars (5), and the plurality of reinforced concrete precast beams (3) and the precast beam stirrups (8) are welded to each other via steel bars.

4. The beam-column node structure of an assembled building frame structure according to claim 1, characterized in that: A mortar seat layer (13) is provided at the bottom connection position of the upper reinforced concrete prefabricated column (2).

5. The beam-column node structure of the assembled building frame structure according to claim 1 is characterized by: The template (10) is fixed on the reinforced concrete prefabricated beam (3) by means of bolts.

6. The beam-column node structure of the assembled building frame structure according to claim 1 is characterized by: The column cross-sectional dimensions of the lower layer precast reinforced concrete column (1) and the upper layer precast reinforced concrete column (2) are 700 mm×700 mm, the column cap (4) has a cross-sectional dimension of 1260 mm×1260 mm, the beam cross-sectional dimension of the precast reinforced concrete beam (3) is 500 mm×1050 mm, and the beam cross-sectional dimension of the precast reinforced concrete beam (3) paved with secondary cast-in-place concrete (9) is 500 mm×1200 mm.

7. A method for implementing a beam-column node of an assembled building frame structure, comprising the following steps: S1: Set a hoisting point on the top of the lower reinforced concrete precast column, use a level ruler to accurately place the lower reinforced concrete precast column on the positioning line, insert the reserved anchor longitudinal reinforcement of the precast column into the longitudinal reinforcement anchor hole for temporary fixation, and use special grouting material for grouting construction. After 24 hours, the grouting process is carried out after the grouting reaches a certain strength. After all grouting holes and exhaust holes overflow, the pressure is maintained for 30 seconds; S2: Mark the column cap and lay out the positioning line of the reinforced concrete precast beam on the column cap. After the reinforced concrete precast beam is in place, the reserved horizontal anchor bars and bottom additional bars of the reinforced concrete precast beam are closely fitted with the reserved anchor longitudinal bars of the precast column; S3: Use reinforced concrete truss floor decking, cut and lay the material according to the size between the reinforced concrete precast beams, install the beam surface steel bars that have been prepared in advance into the upper longitudinal bars of the beams according to the design drawings and specifications, tie the floor slab steel bottom bars at the trough of the reinforced concrete truss floor decking, use cement pads and short steel bars to control the thickness of the floor decking bottom bar protection layer and the bottom bar position, tie the floor slab surface bars and additional bars according to the wave height and wave distance, and use horse stools to control the height of the floor slab surface bars; S4: Before pouring the floor, re-measure the elevation control steel bar elevation and the bottom elevation of the steel decking of all slabs in the pouring area to ensure that the thickness of the poured floor meets the design requirements, and re-check the thickness of the floor steel bar protective layer. When pouring, use a vibrating rod to vibrate it thoroughly.

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