The Performance Research Of Mixed Erection Formwork Support System Under Bi-directional Load

For formwork support system, vertical load is the most common load. But in a fewcases, the formwork support system will suffer bi-directional load. What’s more, theapplication of mixed erection formwork support system under bi-directional loadbasically has none. Based on a mixed erection formwork support system underbi-directional load, the stress of the steel pipe is measured while concrete is poured.According to the measured results, this kind of formwork can be used in project, and itcan exert the advantage of the different frame body. Extensive analysis of measured data,the standard value of the construction load has been derived, the lateral pressure offormwork has been calculated, and synergy between formwork support system andconcrete floor has been identified. The main content is presented as follows：(1) Mixed erection formwork support system can be used in project, but theerection quality must be guaranteed.(2) While the concrete pouring, the impact load and the vibration load have a greatinfluence about the stress of pole. This kind of impact will cause10~20MPa stressfluctuation. So the influence of impact load and vibration load must be noted, while thepole stability bearing capacity is calculated.(3) The lateral pressure of formwork showing a convex shape, and the maximumvalue appears in the lower portion.(4) The concrete floor is sandwiched between two formwork support system, whenthe upper template support system is under non-uniform external load, the internal polein lower formwork support system will appear the phenomenon of stress relaxation.(5) Derived the construction load standard value within guaranteed rate of95%, personnel and equipment of the construction load standard value is recommended totake1.0kN/m~2, impact load and vibrators load standard value is recommended to take2.0kN/m~2. This conclusion is consistent with “Technical code for safety of steel tublarscaffold with couplers in construction”(JGJ130-2011).(6) Synergy between formwork support system and concrete floor shows that themajor role of concrete floor is load transfer, instead of bear load.