施工放样基础方法-----已知高程的放样(国外英文资料).docVIP

施工放样基本方法-----已知高程的放样(国外英文资料) The basic method of construction and lofting is known as the lofting of the elevation The high-altitude set of tasks is to set the design elevation to the designated pile position. In engineering construction, such as in the flat ground, the excavation of foundation pit, route for slope and abutment pier design elevation, etc, often need to elevation layout. The method of high range lofting is mainly measured by leveling, and sometimes the method of measuring vertical distance or trigonometric height is measured directly by steel ruler. Elevation layout, the first need in the test zone setting a certain density of leveling point (temporary leveling points) as the lofting points, then according to the design elevation height of lofting point position in the field calibration. Elevation position calibration measures can be determined according to engineering requirements and site conditions, conditions of engineering pile is commonly used in calibration lofting elevation position, can be in row horizontal line or on the side of the wooden calibration on top of the pile; Concrete and masonry projects are usually marked with red paint on their faces or templates. The usual height is lofting In general, the position of lofting elevation is lower than the line of sight and the length of work is not above the level. As shown in figure 2.6, A is A given point, whose height is HA, and wants to set the height for HB at B. Specific lofting process is: first playing A long wooden stake in point B, put level between A and B, at the point A level ruler, rear view A ruler and reading A, calculate the B level ruler should be forward-looking reading B: B = (HA + a) - HB (2.5) Figure 2.6 lofting Erected on point B wooden side level ruler, move up and down level ruler, when the level on the scale reading just as B, draw a horizontal line from the bottom of the pile side close to the feet, the horizontal line is the design elevation position of HB. It can