Tilt observation of building main body?

The inclination, inclination direction and inclination rate of the observation point at the top of the building relative to the fixed point at the bottom or the observation point at the next level shall be determined in the inclination observation of the main body of the building. The overall inclination of a rigid building can be indirectly determined by measuring the differential settlement of the top surface or foundation. The following is the main content of the main building tilt observation brought by Zhong Da Consulting for reference.

The layout of main inclined observation points and stations shall meet the following requirements:

1. When observed from the outside of the building, the location of the station should be selected at a fixed position 0.5 ~ 2.0 times the target height from the visual target 65438 on the direction line perpendicular to the inclined direction. When using the vertical channel inside the building for observation, the center point at the bottom of the channel can be used as the station;

2, for the overall tilt, the observation point and the fixed point at the bottom should be along the vertical line of the corresponding measuring point of the building main body, and arranged up and down correspondingly; For layered tilt, it should be arranged up and down according to layered parts;

3, according to the forward intersection method survey station, the choice of baseline endpoint should consider the requirements of distance measurement or length measurement. According to the direction line horizontal angle method, the station should be set with orientation points.

The sign setting of the main inclined observation point shall meet the following requirements:

1, the observation point signs on the top and wall of the building can be embedded sighting signs. When there are special requirements, it should be specially designed;

2. Tower-shaped buildings, circular buildings and vertical members that are inconvenient to bury signs can aim at the position determined by the same high side cut by the line of sight or take the position controlled by the height angle as the observation point;

3. According to different observation requirements, observation piers or concrete markers with forced centering devices can be used for observation stations and positioning points on the ground;

4. For one-time tilt observation projects, observation point signs can be marked or directly used to meet the requirements of positioning intervisibility, and observation sites can use small marks or temporary signs.

The accuracy of object tilt observation can be based on a given tilt allowable value.

The periodic visual tilt speed of main body tilt observation is observed once every 1 ~ 3 months. When the slope speed is accelerated due to a large amount of stacking or unloading near the foundation and long-term water accumulation in the site. , should increase the number of observations in a timely manner. Tilt observation should avoid the period when strong sunshine and wind load have great influence.

When observing the inclination of the main body from the outside of the building or component, the following theodolite observation methods should be selected:

1 throwing point method. During observation, horizontal reading ruler and other measuring facilities should be placed at the bottom observation point. When placing theodolite projection at each station, the horizontal displacement component between each pair of upper and lower observation point marks should be measured by the positive and negative mirror method, and then the horizontal displacement value (tilt amount) and displacement direction (tilt direction) can be obtained by vector addition;

2 horizontal angle measurement method. For tower-shaped and circular buildings or components, the observation of each station should take the orientation point as zero, measure the orientation value of each observation point and the distance to the bottom center, and calculate the horizontal displacement component of the top center relative to the bottom center. For rectangular buildings, the angle between the top observation point and the bottom observation point or the angle between the upper observation point and the lower observation point can be directly observed at each station, and the overall or layered horizontal displacement component and displacement direction can be calculated according to the measured angle value and distance value;

3 Forward intersection method. The selected baseline should form the best configuration with the observation point, and the intersection angle should be between 60 ~120. The horizontal displacement can be calculated by direction difference intersection method, and the coordinate change can be calculated directly from the difference of observation direction values in two periods, or by calculating the coordinate values of observation points in each period, and then the horizontal displacement can be calculated from the coordinate difference.

When using the vertical visibility condition between the top and bottom of a building or component to observe the inclination of the main body, the following observation methods should be selected:

1, laser plumb observation method. A receiving target should be placed at an appropriate position at the top, and a laser plumb or laser theodolite should be placed on the ground or floor below its vertical line. Observe at a certain period, and directly read or measure the horizontal displacement and displacement direction of the gyro on the receiving target. When operating, the instrument should be strictly leveled and centered, and rotate 180 to observe the number twice. For super high-rise buildings, when the instrument is located inside the building, the influence of atmospheric turbulence should be considered;

2, laser displacement meter automatic recording method. The displacement meter should be installed on the ground floor or basement of the building, the receiving device can be located on the top floor or the observed floor, the laser channel can be separated by unused elevator shafts or stairs, and the test room should be selected on the floor near the top floor. When the displacement meter emits laser, the displacement image and related parameters can be obtained directly from the optical oscilloscope in the test room, and the results can be recorded automatically.

3, positive and negative vertical method. The vertical line shall be made of stainless steel wire or invar wire with a diameter of 0.6 ~ 1.2 mm and protected by seamless steel pipe. When the normal vertical line method is adopted, the upper end of the vertical line can be anchored at the fulcrum set at the top of the channel or at the required height. When the inverted vertical line method is adopted, the lower end of the vertical line can be fixed on the anchor block, and the upper end is equipped with a buoy. The oil tank used to stabilize the weight and float should be filled with damping fluid. During observation, the horizontal displacement of each measuring point is measured according to a certain period by measuring equipment such as coordinate instrument, optical pendulum and induction pendulum placed on the observation pier;

4, hanging ball method. At the observation point at the top or the required height, hang a vertical ball with appropriate weight directly or at one point, and fix reading equipment such as millimeter grating reading board at the bottom below the vertical line to directly read or measure the horizontal displacement and displacement direction of the upper observation point relative to the lower observation point.

When the relative settlement is used to indirectly determine the overall inclination of the building, the following methods can be selected:

1, inclinometer recording method. Water pipe inclinometer, horizontal pendulum inclinometer, bubble inclinometer or electronic inclinometer can be used for observation. The inclinometer shall have the functions of continuous reading, automatic recording and digital transmission. When monitoring the inclination of the upper floor of a building, the instrument can be placed on the floor of the top floor of the building or on the observed floor. When monitoring the foundation tilt, the instrument can be placed on the foundation surface, and the measured horizontal tilt value of the floor or foundation surface can be used to reflect and analyze the change degree of the building tilt;

2. Determination method of foundation settlement difference. On the basis of selecting observation points, the overall inclination and inclination direction of the building are calculated by using leveling method and converting the foundation settlement difference measured in each period.

When the number of observation points on the building facade is large or the inclination deformation is large, laser scanning or digital close-range photogrammetry can be used, and the specific technical requirements will be designed separately. The following charts shall be submitted for tilt observation:

1, inclined observation point layout;

2, tilt observation results table;

3, the main body tilt curve.

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