Study On The Force Performance Of New Assembled Reinforced Truss Concrete Laminated Slab

With the rapid development of economy and the transformation and upgrading of the construction industry,China has begun to vigorously promote ’ building industrialization and housing industrialization ’.The Ministry of Housing and Urban-Rural Development of the State Council has successively issued policy implementation guidance related to prefabricated buildings,and adopted corresponding incentive measures to provide support for the promotion,application and development of prefabricated buildings.The reinforced truss concrete composite slab has good mechanical properties and is widely used in prefabricated buildings in China.At present,the commonly used steel truss concrete prefabricated floor has protruding truss steel bars on the surface and protruding force bars at the end of the plate.The existence of reinforcement has brought many inconveniences to the production,transportation,construction and installation of prefabricated floor,which has a serious impact on the progress of the project and structural safety,and hinders the development of prefabricated buildings.In order to improve the installation efficiency of prefabricated floor and further promote the application of prefabricated components,this paper proposes a new type of composite plate structure with concave-convex plate end without reinforcement,and verifies the mechanical performance of the new composite plate by experiment combined with finite element method.The specific work is as follows :(1)The construction method,manufacturing method,construction checking and installation steps of the new composite slab are proposed.On the basis of the traditional reinforced composite slab,the new composite slab has reformed the shape of the bottom plate,the form of the stressed steel bar and the overlap mode of the steel bar at the end of the slab.The construction calculation is analyzed according to the relevant requirements of the ’ Code for Construction of Concrete Structures(GB50666-2011).The production and installation steps can be flexibly adjusted under the premise of ensuring the mechanical performance.(2)The static load test of the new composite slab double-span specimen is designed to verify the mechanical performance of the new composite slab.During the loading process,the composite surface did not fail.The crack development process of the specimen was basically consistent with the crack development trend of the cast-in-place one-way slab.There was no oblique crack on the surface of the composite slab,and the failure form was consistent with the bending failure form.By comparing the theoretical calculation value and the measured value,it is found that the cracking load of the middle support of the specimen is close to the calculated value of the specification,which can be estimated by the formula proposed by the specification.The ultimate load of the actual bearing capacity is close to the ultimate load calculated by the plastic analysis theory,and the plastic analysis method can be used to estimate the ultimate bearing capacity of the new composite slab.The deflection value of the characteristic load is far less than the specified value of the specification,and the stiffness meets the requirements of the specification.(3)Using ABAQUS finite element software,the full size model of the specimen is established,and the similarities and differences between the test and the simulation are compared.The influence of additional steel bars at the end of the plate,the arrangement of reinforcing steel bars and the length of the end of the plate into the support on the force of the new composite slab joint is analyzed.The results show that the experimental results are in good agreement with the simulation results,and both of them are scientific and reasonable.When the plate end is subjected to positive bending moment,the arrangement of additional reinforcement and reinforcing reinforcement at the plate end has a great influence on the mechanical performance of the joint.When the slab end bears negative bending moment,increasing the extension length of the precast slab or changing the arrangement of the steel bars at the slab end has little effect on the improvement of the bearing capacity of the beam-slab joints.Finally,the flexural performance of the new composite plate is good,and its integrity,crack resistance,bearing capacity and stiffness all meet the requirements of the specification.