ATTEN: Manager Liu
ADD: Longhua Development Zone, Jing County, Hengshui City, Hebei Province
5. Simulating analysis of unloading and structural system transformation process of temporary support system 5.1 unloading control principles and unloading schemes will cause redistribution of internal force of permanent structure due to temporary support structure? Loading or structural system transformation, which will inevitably have a greater impact on the force of local components of permanent structure. Therefore, permanent structure is in the process of structural system transformation. Force behavior and safety are closely related to unloading process of temporary braced structures 5.1.1 Control principle of unloading process 1) Internal force changes caused by structural system transformation should be slow 2) During unloading process, internal forces of structural members should be within the elastic range and gradually approaching the design state 3) During unloading process, winter temporary support points should be adopted. Unloading deformation should be coordinated (4) Unloading process should avoid inappropriate environmental conditions, such as gale, rain and snow weather 5) Unloading process should be easy to adjust and control, safe and reliable. 51.2 The unloading sequence of the support points in the unloading program is as follows: installing welded steel column supports to unload the outer ring steel columns: selecting 12 support points at the same time at the same interval to unload the support points on the middle ring bone-shifting track; at the same time, unloading the support points on the inner ring-shifting track according to the principle of "deformation coordination, unloading balance", by placing them on the support. The jack of adjustable point support device shows "load balance transfer" under repeated cycling trace.
The condition of temporary support is equivalent to the uneven settlement of the support, which will cause the change and adjustment of the internal force of the truss structure. In case of possible overload of a small number of members, measures should be taken to strengthen them locally in advance. In order to prevent individual support points from concentrating on force, it is advisable to adopt the method of dividing, decreasing proportionally in stages or using the method of equal step descent less than 10 mm per step to dismantle the unloading process of the 5.2 temporary support system. The specific contents of the unloading process need to be determined include: unloading steps, each unloading step. The number and range of synchronous unloading points in each step and the displacement needed to be controlled in each step. Safe and reasonable unloading schemes need to be calculated and compared repeatedly. The calculation process is as follows: (1) According to the scheduled unloading plan, the forced displacement of the set value is applied to the synchronous unloading chamber at the first unloading synchronization, and the inner part of the grate structure system is counted. According to the calculation results, the safety and structural deformation of the grate permanent structure members are checked, and whether the reaction force of the temporary support structure exceeds the original design 3) the permanent structure and the temporary structure are checked. The brace structure meets the requirements. On the basis of the results of the first unloading step, the forced displacement value of the second unloading step is applied to calculate the internal force and displacement of the structure system. Otherwise, the forced displacement value is adjusted and the calculation of the first unloading step is carried out again.
(4) Next step calculation is carried out sequentially until all unloading steps are completed. If multiple chirp forced displacement values, permanent knot and temporary support structures fail to meet the safety requirements, the unloader should be adjusted to recheck. 5.3.1 After unloading, the deformation analysis of steel roof only considers the weight of structural parts and multiplies the weight of joints by 1.1 coefficient. After unloading, the deformation of steel roof is calculated according to the above steps (Fig. 14).