Double-lever stretching creep device with continuously adjustable load and test method thereof

Abstract

The invention relates to a double-lever stretching creep device with a continuously adjustable load and a test method thereof. The device comprises a fixed steel frame, a main load bearing lever, a main load bearing support, an auxiliary load bearing lever, an auxiliary support, a protection device, a constant-load balance weight device, a slidable balance weight device, an adjustable connecting device, a concrete test piece device and a load sensor. The lower ends of the main load bearing support and the auxiliary support are fixedly connected to the fixed steel frame. The main load bearing lever is connected with the main load bearing support by a main bearing; and the auxiliary load bearing lever is connected with the auxiliary support by the main bearing. One end of the main load bearing lever is connected with the fixed steel frame by the concrete test piece device; and the other end of the main load bearing lever is connected with the auxiliary load bearing lever by the adjustable connecting device. According to the r stretching creep device, the gravity load is increased by the double levers and the load amplification factor not lower than a ratio of 10 to 1 can be realized.The whole stretching creep device and scheme are simple and are easy to operate; and the safety and reliability are high.

Description

technical field [0001] The invention relates to the field of concrete structures and materials, in particular to concrete tensile creep test technology, in particular to a double-lever tensile creep device with continuously adjustable load and a testing method thereof. Background technique [0002] In recent years, there have been more and more researches on the tensile creep of concrete at home and abroad, and the number of testing instruments has increased accordingly. Traditional testing instruments have many problems that are difficult to solve. For example, spring creep meters and hydraulic creep meters can only measure pressure creep, but tensile creep plays a more important role in both the material field and the structural field, and is an important content of concrete research. From the material point of view, due to the early hydration and heat release of concrete, a large temperature shrinkage deformation will occur after the temperature is lowered, and a high res...

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Problems solved by technology

Therefore, the applied load cannot be accurately adjusted to the specific data value. Taking a 50kg steel plate as an example, the load can only be increased or decreased by 500Kg each time, and it is difficult to ensure that the target load value is applied.

[0004] The existing methods of fine-tuning the load and controlling the loading rate are mainly the water tank method and the jack method. However, the evaporation of water in the water tank method will easily lead to load changes during long-term load holding, and the jack can only control the loading rate at the beginning.

[0005] Therefore, the existing method cannot achieve continuous adjustment of the applied load and maintain a fixed target value for a long time

In terms of load magnification, although the existing lever-type pull-creep device can amplify the load, due to space constraints, the lever arm cannot be made too long, and the magnification is not enough

In addition, because the lever arm is too long, the height of the loading end from the ground is large during the initial installation, and the safety risk is great.

Blindly increasing the weight of the loading end also increases safety risks

In general, excessively long lever arms and excessively heavy loading cannot meet safety requirements

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