39 results about "Restraint stress" patented technology

The invention discloses a construction method for prestressed fiber restraining concrete members. In the process of manufacturing concrete members, fiber cloth is made into a cylinder at first, and then the concrete added with expansive agent is poured into the fiber cloth cylinder. The fiber cloth cylinder is propped to open by the extrusion force which is resulted from a concrete self-weight and vibration process, and the fiber cloth cylinder prevents the concrete from expanding in a reverse direction, which leads the fiber cloth cylinder to produce restraint stress to the concrete; in a concrete solidification process, the concrete continues expanding under the action of the expansive agent, which leads the fiber cloth produce restraint stress for a second time; in such a method, the prestressed fiber restraining concrete members are made. The creativity of the invention lies in that owing to adopting a structure of prestressed fiber restraining concrete members, the bearing capacity and ductility of concrete members are greatly raised; owing to adopting nonmetallic material as prestressed material, the structural cost is greatly reduced; besides, protective layers which are necessary for reinforced concrete members are saved and the problem of durability is solved once and for all.

The invention discloses a total stress computing method and safety pre-warning method of a large-span steel box girder bridge based on monitored data and temperature stress analysis. The total stress computing method comprises a step 1 of acquiring the strain and the temperature of the bridge by using a health monitoring system; a step 2 of separating temperature strain from the actually measured strain; a step 3of computing the uniform temperature and gradient temperature on the upper cross section of the steel box girder; a step 4 of computing axial restraint stress; a step 5 of computing bending restraint stress; a step 6 of computing temperature self-stress; a step 7 of acquiring geostatic stress from a finite element model; and a step 8 of computing the total stress of the large-span bridge in operation. Compared with a conventional early warning method, the early warning method is clear in early warning index and clear in mechanical model, takes account of the influence of temperature load on the large-span bridge structure, and is applicable to popularization in engineering field.

The invention discloses an adjustable welding restraint stress testing device. The adjustable welding restraint stress testing device comprises a force application unit, a fixture unit and a body unit, the fixture unit is arranged between two transverse rods on the body unit, the force application unit is corresponding to a weld element on the body unit, and pressure is applied to the weld element through an adjustable screw rod; the fixture unit comprises an upper press plate, a bolt and a lower press plate, and the weld element passes through the upper press plate and lower press plate to fix on the body unit in a compression mode through the bolt. The adjustable welding restraint stress testing device is capable of quickly and conveniently measuring the critical restraint degree and critical restraint stress of the cold crack of a weld assembly so as to provide a scientific basis for formulating reasonable welding parameters and technology conditions; the adjustable welding restraint stress testing device is convenient to use, scientific and reasonable in structure, simple in production technique, low in manufacturing cost and easy to popularize; the adjustable welding restraint stress testing device can be broadly used for the welding restraint degree evaluation test for different kinds of steels.

Provided are a testing device and a testing method for a relation between a restraint stress and an extrusion deformation of a tunnel face. A cylindrical pressure chamber is formed by means of a side wall, a top cover and a pedestal in a sealing embedded manner. An oil cylinder is fixed in a groove arranged in a central part of an upper surface of the pedestal. A piston which is in the oil cylinder stretches upwardly into the pressure chamber. An exhaust valve is disposed closed to the side wall on the top cover. An air cylinder barrel, which is smaller than the oil cylinder in diameter, is sealedly embedded on an air cylinder groove arranged in the central part of a bottom surface of the top cover. The air cylinder groove is provided with a vent hole which stretches out through the top cover. A piston in the air cylinder is connected to a displacement measuring rod. An upper end of the displacement measuring rod stretches out from the top cover and is connected to a displacement dial gauge. A water inlet valve is disposed on a position of the pedestal, wherein the position is between an inner chamber of the pressure chamber and the oil cylinder. With the testing device, the relation between the restraint stress and the extrusion deformation of a tunnel face can be accurately tested under different conditions of surrounding rock, thereby providing reliable testing data for design and construction of a tunnel. On the premise of effectively ensuring stabilization of the tunnel face, construction cost is reduced and construction speed is increased.

The invention discloses a column pier type bridge anti-shifting device. The column pier type bridge anti-shifting device is characterized by comprising two groups of beam body fixing assemblies which are arranged on left and right sides of the lower surface of a beam body along the width direction, wherein each beam body fixing assembly comprises an anchoring bottom plate, and the anchoring bottom plate is arranged along the width direction of the beam body and is anchored and connected onto the beam body; each anchoring bottom plate is internally provided with a displacement following plate which is vertically arranged downward along the longitudinal direction of the beam body; an elastic component is horizontally arranged between lower sides of the two displacement following plates in the left-right direction; and the elastic component takes a bridge pier below the beam body as the mounting supporting foundation and is mounted on a hoop fixed on the bridge pier. The invention further discloses a column pier type bridge anti-shifting method adopting the device. The column pier type bridge anti-shifting device has the advantages that the structure is simple, the construction is convenient, the horizontal restraining on a beam body of the bridge can be realized very well, the restraint stress can be released and potential safety hazard is reduced.