Mar.27th, a group of customers visited our factory. They had been our customer since 2015. Mr. Tan was the technical engineer, together with his two bosses they were here looking for more products procurement.
The customers have been using our hydraulic jacks for stake loadcell test, Ningbo Instruments Mechanics Co., Ltd provided the hydraulic jack and pumps for the customers’ East Malaysia Highway project bridging lifting and support.
They used the hydraulic jacks for calibration.
The jack used in the jack calibration method is a common screw jack. When calibrating, place the jack on a stand at the mouth of the cup. The head of the jack is placed on a reserved or rear chiseled groove of the concrete column. The angle between the axis of the jack and the horizontal plane should not be too large. If it is too large, the concrete of the column will be broken. In order to overcome this shortcoming, a short steel bar of 020~25 and 150mm length can be embedded in the column body, and 30~50mm of the cylinder surface can be extended as the support of the head of the jack, and the steel chain can be used as a support on the end of the column. This angle can be larger. When the calibration is performed, the crank is rotated and the neck of the jack is extended to correct the column.
The screw jack is suitable for correcting columns with a mass of less than 20t. In the correction, it should be noted that the first step should be large and then small, and the plane position should be reviewed after the verticality correction. In addition, due to the sun exposure, the temperature difference between the two sides of the column will also cause the column to bend, resulting in horizontal displacement of the top of the column. Horizontal displacement size and column two
Generally 3~10mm, the slender column can reach more than 30mm. Therefore, the influence of the temperature difference of the sunlight on the vertical deviation should be considered when performing the correction of the slender column. In order to reduce the influence of temperature difference on the verticality correction of the column, the correction work can be carried out when the influence of sunlight such as cloudy, morning and dusk is small; or according to experience, the method of setting the deviation can be used to solve the problem; when the length of the column is less than 10 m Generally, the influence of temperature difference is not considered.