Study On The Force Performance Of Precast Concrete Base Slab With Steel Pipe Joist

The characteristics of assembled buildings coincide with the urgent requirements of China’s current stage in the pursuit of high-quality products to meet our The characteristics of assembled buildings are in line with the urgent demand for high quality products at this stage of China’s development,meeting the needs of our refined and distinctive urban development.Compared with traditional building slabs,they have high construction efficiency,short project cycle and good seismic performance.However,there are also many problems with these slabs,such as thicker slabs,the need to set up supports during the construction stage,complicated installation steps,steel bars going out on all sides and low integration standards.It does not meet the needs of China’s current stage of promoting the factoryisation of the construction industry,increasing the proportion of standardised construction in the construction phase and improving the quality of buildings.In order to improve the load carrying capacity of the current stage of the stacked slab and to solve the problems arising from the application of the current stage of the stacked slab,the structure of the stacked slab was improved on the basis of the existing steel truss concrete stacked slab to form a steel tube truss concrete stacked slab.The mechanical properties of the steel pipe truss concrete precast base slab as the bottom mould of the castin-place concrete layer of the stacked slab are of paramount importance.The four precast base slabs were subjected to uniform loading tests to study the web strain,mid-span deflection variation,crack distribution pattern and top chord steel pipe strain of the precast base slab.The mechanical properties were investigated.Relevant measurement points were deployed to monitor the concrete strain,deflection variation,and strain of the top chord steel pipe and web of the precast concrete base slab of the steel pipe truss.Analysis of the mechanical performance of the precast concrete base slabs of steel pipe trusses under uniform load,and summary of the cracking and ultimate loads of the precast base slabs.Parametric analysis is carried out by varying the concrete strength class,height of the steel pipe trusses,spacing of the steel pipe trusses and diameter of the webs in the precast footings.Cracks in the back of the precast footing mainly appear in the mid-span position and are evenly distributed to both sides as the load increases.Contrast analysis shows that increasing the concrete strength grade can effectively reduce the deflection of the precast footing,raise the cracking load of the footing,make the bearing capacity of the precast footing higher and slow down the crack generation rate of the precast footing.The height of the steel pipe joist has a greater influence on the precast slab.The height of the steel pipe joist can increase the load bearing capacity of the precast slab and effectively reduce the possibility of cracking of the precast slab,while reducing the height of the joist will reduce the load bearing capacity and the overall performance of the precast slab.The change in web diameter has a small effect on the load bearing performance of the precast slab and,for economic reasons,a 6mm web is recommended.Figure [81] Table [17] Reference [64]...