WO2022007608A1

WO2022007608A1 - Rammed earth and wood beam joint bending resistance and deformation performance testing device and using method thereof

Info

Publication number: WO2022007608A1
Application number: PCT/CN2021/100644
Authority: WO
Inventors: 郑双杰; 范慧敏; 扶庆祝; 焦礼哲; 陈明杰
Original assignee: 华侨大学
Priority date: 2020-07-06
Filing date: 2021-06-17
Publication date: 2022-01-13
Also published as: CN111751226B; CN111751226A

Abstract

A rammed earth and wood beam joint (6) bending resistance and deformation performance testing device and a using method thereof. The testing device comprises: a confinement mechanism (5), which comprises an accommodating cavity and a top pressing plate (16); a bending moment loading mechanism (1), which comprises a first balancing reaction frame (9) and a bending moment applier (7) capable of vertically pulling up or pressing a suspended end of a wood beam (21) to apply a positive bending moment or a negative bending moment to a rammed earth and wood beam joint (6); an axial force loading mechanism (2), which comprises a second balancing reaction frame (91) and an axial force applier (8) capable of applying an axial force to the top pressing plate (16) to further transfer the axial force to a rammed earth block (20), thereby simulating a gravity effect in the vertical direction; and a side pressure loading mechanism (3), capable of applying pressure to a side surface of the rammed earth block (20) and located in the accommodating cavity. The testing device can be quickly assembled and disassembled and can be repeatedly used for multiple times, facilitates the application of load effects of rammed earth and wood beam joints in all directions, and effectively prevent rammed earth blocks from being crushed in the repeated use process.

Description

Test device for flexural load-bearing and deformation performance of rammed earth and wooden beam joints and its use method

technical field

The invention relates to the technical field of experiments on civil and architectural structures, in particular to a test device for the flexural bearing and deformation performance of rammed earth and wooden beam joints and a method for using the same.

Background technique

Rammed earth structure is a common form of ancient building structure. It is widely used in traditional Chinese architectural structures such as Tibetan ancient buildings, Fujian tulou, northwest dwellings, and ancient city walls. It is one of the key protection and research objects of historical building structures in my country.

Embedding wooden beams into rammed earth walls and combining wooden columns with wooden floor slabs and other components to form a synergistic stress system is an effective form to exert the performance and space efficiency of rammed earth structures. The load follows the following transfer path: first the wood floor directly bears the floor load, then it is transferred to the beam lattice structure formed by the wood beams, then it is transferred down to the wood columns and rammed earth walls at both ends of the wood beams, and finally the wood columns and rammed earth walls Transfer loads to foundations and foundations. In this load transfer path, the rammed earth and wood beam joints are the junction of dissimilar materials, which play the role of linking the upper and lower, and are the key part to exert the performance of the rammed earth structure. It must be ensured that it has sufficient flexural bearing capacity and deformation performance.

Most of the existing bending test devices are a combination of a reaction frame and a jack, which are mainly suitable for steel beams, concrete beams or steel-concrete composite joints. It is easier to anchor; the side and top surfaces of the component are easy to apply other loads, such as simulating gravity and applying vertical pressure through jacks, simulating lateral restraint and applying horizontal pressure through jacks or prestressing, etc. However, when these devices are used for flexural loading tests of rammed earth and wooden beam joints, there are still some shortcomings: rammed earth is relatively loose before forming, and is prone to brittle failure even if it is formed, and it is difficult to anchor on the ground or other reaction devices. Installation and disassembly are inconvenient; it is difficult to apply loads evenly on the top and side surfaces of the rammed earth, and it is easy to concentrate local forces and cause the rammed earth blocks to collapse.

SUMMARY OF THE INVENTION

The present invention provides a test device for flexural bearing capacity and deformation performance of a rammed earth and a wooden beam joint and a method for using the same, which overcome the shortcomings of the background technology. One of the technical solutions adopted by the present invention to solve its technical problems is:

A test device for flexural bearing and deformation performance of rammed earth and wooden beam joints. The rammed earth and wooden beam joints include a rammed earth block and a wooden beam with one end inserted into the rammed earth block, and the other end of the wooden beam is suspended. The test device includes:

The hoop mechanism includes an accommodating cavity and a top pressure plate, the rammed earth block is placed in the accommodating cavity and the suspended end of the wooden beam protrudes out of the accommodating cavity, and the top pressure plate is covered on the rammed earth block and can be placed in the accommodating cavity. The accommodating cavity moves up and down;

A bending moment loading mechanism, which includes a first balance reaction frame and a bending moment application capable of pulling or pressing the suspended end of the wooden beam in the vertical direction to apply a positive or negative bending moment to the rammed earth and the wooden beam joint a force applicator, the bending moment force applicator is installed on the first balance reaction frame;

The axial force loading mechanism includes a second balance reaction frame and an axial force applicator that can apply an axial force to the top pressure plate and then transmit it to the rammed earth block to simulate the action of gravity in the vertical direction, and the axial force applicator is installed on the on the second counterbalance; and

The side pressure loading mechanism that can exert pressure on the side of the rammed earth block is located in the accommodating cavity.

In a preferred embodiment: the side pressure loading mechanism includes two side pressure plates and a number of anti-tension bolts, the rammed earth block is located between the two side pressure plates, and the two ends of the anti-tension bolts are respectively connected to the two side pressure plates, Lateral pressure can be applied to the rammed earth block by tightening the nuts to move the two side pressure plates towards each other.

In a preferred embodiment, there are four said pair of tension bolts and are arranged around the rammed earth block at annular intervals.

In a preferred embodiment: the side wall of the accommodating cavity is provided with a number of side holes corresponding to the pull bolts; the front wall of the accommodating cavity is provided with end holes, and the wooden beam The suspended end protrudes from the accommodating end hole, and the accommodating end hole extends along the height direction of the accommodating cavity to make way for the deformation of the wooden beam.

In a preferred embodiment, the test device further includes an ground anchor mechanism, the ground anchor mechanism includes an ground anchor base and an ground anchor screw installed on the ground anchor base, and the ground anchor base is fixedly connected outside the accommodating cavity.

In a preferred embodiment, the ground anchor mechanism is provided with two groups, which are respectively connected with the front and rear side walls of the accommodating cavity.

In a preferred embodiment, a pad is arranged on the top surface of the top pressure plate, and the axial force applicator corresponds to the pad.

The second of the technical solutions adopted by the present invention to solve its technical problems is:

The method of using the test device for the flexural bearing capacity and deformation performance of rammed earth and wooden beam joints, which applies the test device for flexural bearing capacity and deformation performance of rammed earth and wooden beam joints described in any one of the above, including:

Step 10: Fix the ground anchor base of the ground anchor mechanism with the accommodating cavity, then place the side pressure loading mechanism in the accommodating cavity, and then fill the rammed earth blocks into both sides of the side pressure loading mechanism Between the pressure plates, insert one end of the wooden beam through the accommodating cavity and insert it into the rammed earth block, and then cover the top pressure plate to form a model specimen of the joint between the rammed earth block and the wooden beam;

Step 20, hoist the model specimen made in step 10 to the test site, lock the ground anchor base on the ground through the ground anchor screw, and install the bending moment loading mechanism and the axial force loading mechanism, so that the shaft The force applicator corresponds to the center of the top pressure plate, and the moment force applicator corresponds to the suspended end of the wooden beam;

Step 30, by tightening the pair of tensioning screws to move the two lateral pressure plates toward each other to exert constant lateral pressure on both sides of the rammed earth block to simulate the lateral pressure on both sides of the rammed earth wall; The top pressure plate exerts a downward vertical axial force to drive the top pressure plate to move downward until the top pressure plate is pressed against the top surface of the rammed earth block, and the axial force applicator continues to exert force to apply a constant direction to the top surface of the rammed earth block. The vertical axial force under the rammed earth wall is used to simulate the vertical gravity effect of the rammed earth wall; the suspended end of the wooden beam is pulled or pressed by the bending moment applicator in the vertical direction, so that the connection between the rammed earth and the wooden beam is connected. Apply positive or negative bending moments to test the flexural bearing and deformation performance of rammed earth and wood beam joints.

In a preferred embodiment: in step 10, the ground anchor base and the accommodating cavity are connected by welding; in step 20, the first balance reaction frame and the ground are locked by bolts, and the second The balance reaction frame and the ground are locked by bolts.

Compared with the background technology, the technical solution has the following advantages:

1. The test device can not only be installed and disassembled quickly, but also can be reused many times, which is convenient for applying the load in all directions between the rammed earth and the wooden beam joints. The force device exerts pressure on the top pressure plate instead of directly exerting pressure on the rammed earth block, so that the rammed earth block can be effectively avoided in the process of repeated use.

2. The side pressure loading mechanism includes two side pressure plates and several counter-tension bolts. The rammed earth block is located between the two side pressure plates. By tightening the nuts of the counter-tension bolts, the two side pressure plates can be moved toward each other to clamp the rammer. The soil block is easy to adjust, and the side force of the rammed earth block is more uniform, and the phenomenon of the collapse of the rammed earth block caused by the concentration of force will not occur.

3. Four tie bolts are arranged around the rammed earth block at annular intervals, which further makes the lateral pressure on the rammed earth block more uniform.

4. The ground anchor mechanism includes the ground anchor base and the ground anchor screw installed on the ground anchor base. The ground anchor base is fixed outside the accommodating cavity, and the ground anchor screw can be locked with the ground anchor hole on the laboratory ground. convenient.

5. The top surface of the top pressure plate is provided with a cushion block, so that the force exerted by the axial force applicator on the top pressure plate can be dispersed and transmitted through the cushion block to avoid stress concentration.

Description of drawings

The present invention will be further described below with reference to the accompanying drawings and embodiments.

FIG. 1 is an overall schematic diagram of a testing device for flexural load-bearing and deformation performance of rammed earth and wooden beam joints according to a preferred embodiment.

FIG. 2( a ) is a schematic front view of the testing device.

Figure 2(b) shows a side view of the test device.

Figure 2(c) shows a top view of the testing device.

Figure 3(a) shows the structural diagram of the bending moment loading mechanism and the axial force loading mechanism.

Figure 3(b) shows a structural diagram of the side pressure loading mechanism.

Fig. 3(c) shows the structure diagram of the ground anchor mechanism.

Figure 3(d) shows the structure of the ferrule mechanism.

Figure 3(e) shows the structural diagram of the rammed earth and wood beam joints.

detailed description

In the claims, description and the above drawings of the present invention, unless otherwise clearly defined, the terms "first", "second" or "third" are used to distinguish different objects, rather than used for Describe a specific order.

In the claims, description and the above drawings of the present invention, unless otherwise expressly defined, the terms "center", "horizontal", "longitudinal", "horizontal", "vertical" and "top" are used for directional words. , "bottom", "inside", "outside", "up", "down", "front", "rear", "left", "right", "clockwise", "counterclockwise", etc. The positional relationship is based on the orientation and positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a particular orientation or be constructed and operated in a particular orientation. , so it should not be construed as limiting the specific protection scope of the present invention.

In the claims, description and the above drawings of the present invention, unless otherwise clearly defined, the terms "fixed connection" and "fixed connection" should be understood in a broad sense, that is, there is no displacement relationship and relative rotation relationship between the two. Any connection means, that is to say including non-removable fixed connection, detachable fixed connection, integrated and fixed connection by other means or elements.

In the claims, description and the above-mentioned drawings of the present invention, if the terms "including", "having" and their modifications are used, it is intended to mean "including but not limited to".

Please refer to Figures 1 to 3, a preferred embodiment of the test device for the flexural bearing capacity and deformation performance of the rammed earth and wood beam joints, the described rammed earth and wood beam joint flexural bearing capacity and deformation performance testing device.

As shown in FIG. 3(e), the rammed earth and wooden beam joint 6 includes a rammed earth block 20 and a wooden beam 21 whose one end is inserted into the rammed earth block 20, and the other end of the wooden beam 21 is suspended. Moreover, the rammed earth block 20 is square, the wooden beam 21 is elongated, and the wooden beam 21 and the rammed earth block 20 are vertically arranged.

The test device includes a hoop mechanism 5 , a bending moment loading mechanism 1 , an axial force loading mechanism 2 and a side pressure loading mechanism 3 .

The hoop mechanism 5 includes an accommodating cavity and a top pressure plate 16. The rammed earth block 20 is placed in the accommodating cavity and the suspended end of the wooden beam 21 protrudes out of the accommodating cavity. The top pressure plate 16 is covered on the rammed earth. The block 20 can move up and down in the accommodating cavity. As shown in FIG. 3( d ), the accommodating cavity has a square shape and is surrounded by the side orifice plate 14 and the end orifice plate 18 .

In this embodiment, the side walls of the accommodating cavity are provided with a number of side holes 15 for giving way; the front wall of the accommodating cavity is provided with end holes 19 for giving way, and one end of the wooden beam 21 is suspended from the end holes for giving way. 19 protrudes, and the accommodating end hole 19 extends along the height direction of the accommodating cavity to make way for the deformation of the wooden beam 21 .

In this embodiment, a pad 17 is provided on the top surface of the top pressure plate 16 , and the axial force applicator 8 corresponds to the pad 17 . As shown in Fig. 3(d), the spacer 17 is disc-shaped and made of steel.

The bending moment loading mechanism 1 includes a first balance reaction frame 9 and a suspended end of the wooden beam 21 that can be pulled or pressed in the vertical direction to apply a positive bending moment or a negative bending moment to the node of the rammed earth 20 and the wooden beam 21 . The bending moment applicator 7 of the moment is installed on the first balance reaction frame 9 . In this embodiment, the first balance reaction frame 9 is in an inverted U shape, which can be fixed with the ground by bolts, and the bending moment force applicator 7 can be a jack.

The axial force loading mechanism 2 includes a second balance reaction force frame 91 and an axial force applicator 8 that can apply an axial force to the top pressure plate 16 and then transmit it to the rammed earth block 20 to simulate the action of gravity in the vertical direction. The force applicator 8 is mounted on the second balance reaction force frame 91 . In this embodiment, the second balance reaction frame 91 is in an inverted U shape, which can be fixed with the ground by bolts, and the axial force applicator 8 can be a jack. As shown in FIG. 3( a ), the bending moment loading mechanism 1 and the axial force loading mechanism 2 are arranged at intervals in the front and rear.

The side pressure loading mechanism 3 can exert pressure on the side of the rammed earth block 20, which is located in the accommodating cavity.

In this embodiment, the side pressure loading mechanism 3 includes two side pressure plates 11 and several anti-tension bolts 10 , the rammed earth block 20 is located between the two side pressure plates 11 , and the two ends of the anti-tension bolts 10 are respectively connected to the two side bolts 10 . The pressing plates 11 are connected together, and a lateral pressure can be applied to the rammed earth block 20 by tightening the nuts to move the two side pressing plates 11 toward each other. Moreover, each pair of pull bolts 10 protrudes from one of the corresponding side holes 15 to facilitate the adjustment of the nut.

In this embodiment, there are four tension bolts 10 arranged around the rammed earth block 20 at annular intervals, that is, the side pressure loading mechanism 3 is enclosed in a square, and the rammed earth block 20 can be placed on this side pressure loading mechanism 3.

In this embodiment, the test device further includes an ground anchor mechanism 4, and the ground anchor mechanism 4 includes an ground anchor base 13 and an ground anchor screw 12 installed on the ground anchor base 13, and the ground anchor base 13 is fixedly connected to the accommodation outside the cavity.

In this embodiment, the ground anchor mechanism 4 is provided with two groups, which are respectively connected with the front and rear side walls of the accommodating cavity.

The method of using the test device includes:

Step 10: Fix the ground anchor base 13 of the ground anchor mechanism 4 with the accommodating cavity, then place the side pressure loading mechanism 3 in the accommodating cavity, and then fill the rammed earth block 20 into the side pressure loading mechanism 3, insert one end of the wooden beam 21 through the accommodating cavity and insert it into the rammed earth block 20, and then cover the top pressure plate 16 to form a model test of the rammed earth block and the wooden beam joint 6. In this embodiment, in step 10, the ground anchor base 13 and the accommodating cavity are connected by welding;

Step 20, hoist the model specimen made in step 10 to the test site, the ground anchor holes can be preset, and the ground anchor base 13 is locked on the ground through the ground anchor screw 12, and the bending moment loading is installed. Mechanism 1 and axial force loading mechanism 2, so that the axial force applicator 8 corresponds to the center of the top pressure plate 16, and the bending moment force applicator 7 corresponds to the suspended end of the wooden beam 21; in step 20, the first balance reaction frame 9 and the The ground is locked by bolts, and the second balance reaction frame 91 is locked with the ground by bolts.

Step 30, by tightening the pair of tensioning screws 10 to move the two lateral pressure plates 11 toward each other to exert constant lateral pressure on both sides of the rammed earth block 20 to simulate the lateral pressure on both sides of the rammed earth wall; The force device 8 exerts a downward vertical axial force on the top pressure plate 16 to drive the top pressure plate 16 to move downward until the top pressure plate 16 is pressed against the top surface of the rammed earth block 20. The top surface of the soil block 20 exerts a constant downward vertical axial force to simulate the vertical gravity effect of the rammed earth wall; the wooden beam 21 is suspended in the vertical direction by pulling or pressing the wooden beam 21 through the bending moment force applicator 7 One end of the rammed earth and the wooden beam joint 6 acts a positive bending moment or a negative bending moment, so as to achieve the purpose of testing the flexural bearing capacity and deformation performance of the rammed earth and the wooden beam joint 6.

The test device can not only be installed and disassembled quickly, but also can be reused many times, which is convenient for applying the load in each direction between the rammed earth and the wooden beam joint 6. At the same time, the rammed earth block 20 is placed in the accommodating cavity, and the axial force is applied. The force device 8 exerts pressure on the top pressing plate 16 instead of directly exerting pressure on the rammed earth block 20, so that the rammed earth block 20 can still be effectively prevented from being crushed during repeated use.

The above descriptions are only preferred embodiments of the present invention, so the scope of implementation of the present invention cannot be limited accordingly, that is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the description should still be covered by the present invention. within the range.

Industrial Applicability

The invention discloses a testing device for the flexural bearing and deformation performance of rammed earth and wooden beam joints and a method for using the same. The testing device can not only be quickly installed and disassembled, but also can be reused many times, which is convenient for applying rammed earth and wooden beam joints. At the same time, the rammed earth block is placed in the accommodating cavity, and the axial force applicator applies pressure to the top pressure plate instead of directly applying pressure to the rammed earth block, so that it can be effectively avoided in the process of repeated use. The rammed earth block is crushed and has industrial practicability.

Claims

The test device for the flexural bearing and deformation performance of rammed earth and wooden beam joints. The rammed earth and wooden beam joints include a rammed earth block and a wooden beam whose one end is inserted into the rammed earth block, and the other end of the wooden beam is suspended. It is characterized in that: the The test setup includes:

The hoop mechanism includes an accommodating cavity and a top pressure plate, the rammed earth block is placed in the accommodating cavity and the suspended end of the wooden beam protrudes out of the accommodating cavity, and the top pressure plate is covered on the rammed earth block and can be placed in the accommodating cavity. The accommodating cavity moves up and down;

A bending moment loading mechanism, which includes a first balance reaction frame and a bending moment application capable of pulling or pressing the suspended end of the wooden beam in the vertical direction to apply a positive or negative bending moment to the rammed earth and the wooden beam joint a force applicator, the bending moment force applicator is installed on the first balance reaction frame;

The axial force loading mechanism includes a second balance reaction frame and an axial force applicator that can apply an axial force to the top pressure plate and then transmit it to the rammed earth block to simulate the action of gravity in the vertical direction, and the axial force applicator is installed on the on the second counterbalance; and

The side pressure loading mechanism that can exert pressure on the side of the rammed earth block is located in the accommodating cavity.
The device for testing the flexural load-bearing and deformation performance of rammed earth and wooden beam joints according to claim 1, wherein the side pressure loading mechanism comprises two side pressure plates and a plurality of anti-tension bolts, and the rammed earth blocks are located on the two sides. Between the two side pressure plates, the two ends of the tension bolt are respectively connected with the two side pressure plates, and the lateral pressure can be applied to the rammed earth block by tightening the nuts to move the two side pressure plates toward each other.
The device for testing the flexural bearing capacity and deformation performance of rammed earth and wooden beam joints according to claim 2, wherein four of the tension bolts are arranged around the rammed earth block at annular intervals.
The device for testing the flexural bearing capacity and deformation performance of rammed earth and wood beam joints according to claim 2, wherein the side wall of the accommodating cavity is provided with a plurality of side walls corresponding to the tie bolts respectively. The front wall of the accommodating cavity is provided with an end hole, the suspended end of the wooden beam protrudes from the end hole, and the end hole extends along the height direction of the accommodating cavity to deform the wooden beam give way.
The test device for flexural bearing and deformation performance of rammed earth and wood beam joints according to claim 2, characterized in that: the test device further comprises a ground anchor mechanism, and the ground anchor mechanism comprises a ground anchor base and a ground anchor installed on the ground anchor. The ground anchor screw of the base, and the ground anchor base is fixedly connected outside the accommodating cavity.
The device for testing the flexural bearing capacity and deformation performance of rammed earth and wood beam joints according to claim 5, wherein the ground anchor mechanism is provided with two groups and is connected to the front and rear side walls of the accommodating cavity respectively.
The device for testing the flexural load-bearing and deformation performance of rammed earth and wood beam joints according to claim 1, wherein a pad is provided on the top surface of the top pressure plate, and the axial force applicator is connected to the pad. correspond.
The method of using the test device for the flexural bearing capacity and deformation performance of rammed earth and wooden beam joints, which applies the test device for flexural bearing capacity and deformation performance of rammed earth and wooden beam joints according to any one of claims 5 to 7, wherein Features include:

Step 10: Fix the ground anchor base of the ground anchor mechanism with the accommodating cavity, then place the side pressure loading mechanism in the accommodating cavity, and then fill the rammed earth blocks into both sides of the side pressure loading mechanism Between the pressure plates, insert one end of the wooden beam through the accommodating cavity and insert it into the rammed earth block, and then cover the top pressure plate to form a model specimen of the joint between the rammed earth block and the wooden beam;

Step 20, hoist the model specimen made in step 10 to the test site, lock the ground anchor base on the ground through the ground anchor screw, and install the bending moment loading mechanism and the axial force loading mechanism, so that the shaft The force applicator corresponds to the center of the top pressure plate, and the moment force applicator corresponds to the suspended end of the wooden beam;

Step 30, by tightening the pair of tensioning screws to move the two lateral pressure plates toward each other to exert constant lateral pressure on both sides of the rammed earth block to simulate the lateral pressure on both sides of the rammed earth wall; The top pressure plate exerts a downward vertical axial force to drive the top pressure plate to move downward until the top pressure plate is pressed against the top surface of the rammed earth block, and the axial force applicator continues to exert force to apply a constant direction to the top surface of the rammed earth block. The vertical axial force under the rammed earth wall is used to simulate the vertical gravity effect of the rammed earth wall; the suspended end of the wooden beam is pulled or pressed by the bending moment applicator in the vertical direction, so that the connection between the rammed earth and the wooden beam is connected. Apply positive or negative bending moments to test the flexural bearing and deformation performance of rammed earth and wood beam joints.
The method for using the test device for the flexural bearing and deformation performance of rammed earth and wood beam joints according to claim 8, wherein in step 10, the ground anchor base and the accommodating cavity are connected by welding; In step 20, the first balance-reaction frame and the ground are locked by bolts, and the second balance-reaction frame and the ground are locked by bolts.