SU76028A1 - The method of measuring stresses in massive structures - Google Patents

Description

Existing devices for measuring the magnitude of the rock pressure and stresses in engineering structures, made in the form of a m-anometer, connected by pipeline with an elastic vessel filled with liquid and perceiving the measured pressure inside the medium, have a significant drawback from the point of view of accuracy of readings. In these devices, the stresses acting on the elastic vessel depend on the stiffness ratio of the elastic vessel and its environment.

So, with a very small vessel stiffness compared with the medium stiffness, the device will not perceive almost any stresses, and with a very large vessel stiffness, it will perceive the stresses acting in the structure, but it will hardly register these stresses. as recording devices under these conditions do not give any indication.

The proposed method for eliminating distortions in instrument readings caused by a voltage drop in the surrounding elastic vessel environment during the recording of the display 2 &

The scientific research institute of the manometer consists in determining the hydrostatic pressure in the vessel by the magnitude of the air back pressure generated in the pipeline connecting the elastic vessel with the manometer.

A schematic diagram of a device for measuring stresses in massive structures according to the proposed method is shown in the drawing.

The device consists of a hermetic metal chamber / with corrugated walls, connected by a tube 2 with a tap nozzle 3. Another tap nozzle 3 is connected via a tube 4 to a measuring glass 5 made of a graduated glass tube encased in a metal yoke. Tee 7 combines measuring glass 5 with pressure gauge 6.

The measurement of stresses in buildings is carried out as follows.

The vessel / with tubes 2 and 4 and measuring glass 5 is filled with liquid (water, oil, mercury) so that the meniscus is at the bottom of the measuring glass 5. When the chamber / valve 3 is filled, it closes.

In this state, the device is placed in a building or under A451.

to the base of the foundation, during the construction of the structure (concreting, filling, washing, masonry) so that the crane 3 and the measuring glass 5 are outside, in a place accessible for observation.

The arising normal stresses in the structure or on its surface are completely transmitted to the fluid filling vessel 1 (vessel void / negligible) in which hot water occurs; residual pressure equal to the normal stress in the structure due to incompressibility of the liquid and the small height of vessel 1 .

To measure the hydrostatic pressure, the valve 3 is opened, as a result of which the fluid meniscus rises to a certain height D. After that, the pipe 8 serves compressed air. The air back pressure acting on the fluid is forced, the meniscus is lowered to the initial mark, and the voltage is determined from the reading of the manometer 6.

Predm: em inventions

The method of measuring stresses in massive structures by means of a device made in the form of a pressure gauge connected to an elastic vessel filled with liquid, placed in the thickness of the masonry and perceiving a measurable pressure that differs from that during the recording of stresses, caused by a voltage drop in the surrounding elastic vessel, the magnitude of the hydrostatic pressure in the elastic vessel is determined by the value of the equilibrium air pressure generated in the pipe the gadget connecting the elastic vessel with the manometer.

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