Design And Study Of Stability Capacity Of A New Type Of Formwork Support System

The temporary support structures of constructions have already been an indispensable part for the current construction,and its performances are directly related to the entire construction duration,budget,project quality and other aspects.The traditional formwork support system still used now have many defects,such as long construction duration,high cost,wasting of resources,and even causing collapse accidents.These defects have raised concern in related fields.In order to meet the demand of concrete pouring in a certain construction,a new type of formwork support system,which can form large flat slab areas in a very short period of time has been designed in this thesis.Compared with traditional formwork support system,this new type of formwork support system has advantages as follows:(1)The system's service life can be extended,turnover times can be increased,conservation costs and the labor costs can be reduced by upgrading its materials and treatment process;(2)The design of the new aluminum plate frame for the upper surface slab system can be prefabricated and modularized;The anti-lateral and the flexural behavior of the formwork support system was enhanced by main and minor beam's plug-in connection and the new type of pawl-type head jack.With the application of disk-pin joint node,the formwork support system can improve the construction efficiency greatly;(3)It is more simple and convenient to assemble and disassemble the whole formwork support system.A single worker is capable to complete,thus shortening the entire construction duration;extending working life of the system,reducing the usage of per unit volume,and the engineering costs can be saved apparently.This thesis focus on the new type of formwork support system,mainly carry out researches as follows:(1)The accessories of the new type of formwork support system has designed and developed.As well as its script of whole structure;(2)Experiments have been carried out on the disk-pin joint node and other joints,the semi-rigid connection performance and the sequence of rotational stiffness of these joints have been obtained;(3)Experimental design of the full-scale test and its preparation of the new type of formwork support system have completed.(4)The bearing capacity values of the system has been calculated with buckling analysis of the semi-rigidness of its joint with SAP2000 finite element model of the basic structural unit.,In this thesis,the nodal semi-rigid experimental research,and the SAP2000 finite element buckling analysis have been done.Conclusions have been achieved as follows:(1)The M-?r curve of the disk-pin joint node and that of right-angle coupler node with an initial tightened torque moment of 40N·mare very similar,while the mounting of the disk-pin joint node is more convenient,for this reason,the disk-pin joint node is applied in the new type of formwork support system.(2)The semi-rigid joint has a significant effect on the bearing capacity of the new type of formwork support system.While this effect gets weaker and capacity of the semi-rigid joint nodes are enhanced with the arrangement of the diagonal support increased.(3)According to the diagonal brace arrangement,the Stable bearing capacity of the new type of formwork support system with 2×2 basic structural is about 270~680kN(9.03~26.61 t/m2).Conclusions mentioned above can be used as guidelines for further development of the follow-up research,and has a certain guiding significance for the template support work of construction in process.