Optimal Design Study On Simply Supported Truss Composite Floor System

In the recent years, the rapid development of large-scale public buildings and high-rise buildings has been brought out lots of requirements to the design of large-span structures subjected to heavy loads. At the same time, wasting resources and environmental pollution has become a critical challenge for the structural engineering community. The steel truss-concrete composite beam is a new type of composite beam structure with superior mechanical performance and significant economic benefits in the structure with large span under heavy loads. In addition, it’s easy to implement green construction. This thesis is mainly focused on the study of bearing performance, design procedures, and economic benefits. The main completed work and conclusions are as the followings:1. A shell-solid mixed model based on the general FE package ABAQUS is proposed, and the mechanical property of simply supported steel truss-concrete composite beams are discussed in detail. With the vertified shell-solid mixed model by the experimental results, a parameter study on the stiffness-equivalent effective flange of simply supported steel truss-concrete composite beams is investigated. Then a simplified regression formula of the stiffness-equivalent effective flange width of simply supported steel truss-concrete composite beams is derived based on the parametric study, which can better predict the structural stiffness and the transformation compared with the existing formulas provided in the current design codes. On the basis of the the solid-web composite beams design method in the current norms, the bearing capacity of plastic design method of simply supported truss-concrete composite beam are reviewed.2. Combining with the bearing capacity of plastic design method and controlling the ultimate bearing capacity, a parameter study on the economic indicators of simply supported truss-concrete composite beam and simply supported web-solid composite beam is investigated. It can be found that the depth-span ratio, the chord area ratio of the truss-concrete-composite beam, and the flange area ratio of the web-solid composite beam has great influence on the economic indicators. And economic indicators contrastive analysis of the truss-concrete composite beam and the web-solid composite beam under same parameters is investigated.3. Satisfied the condition of plastic bearing capacity, using beam-slab model in the FE package to do a parameter analysis of the economic indicators of simply supported truss composite floor and simply supported web-solid composite floor with controlling the stress of the composite floor. And economic indicators contrastive analysis of simply supported truss-concrete composite floor and simply supported web-solid composite floor under same parameters is investigated.4. Combined with an optimization design of a practical engineering with lagre span and heavy loeads, it can vertify the structure selection suggestions considering the economic indicators suggested in the thesis. The design results illustrate that simply supported steel truss-concrete composite floor has broad application prospects with excellent menchanical performance and many economic benifits.