Study On The Mechanical Properties And Human-induced Vibration Of Cable Supported Composite Floor System

With the development of modern society in economy,industry,culture,communication and sport fields,the architectural function of buildings become more and more diversified,and the multi-floor large span public building arises.This enhances the requirement of people's activities large span floor system.The application in large span public building of existing traditional floor system cannot reach an ideal standard in aspects of rationality,economy,and ornamental value.To meet large space requirement,an innovative Cable Supported Composite Floor System(CSCFS)with a desirable large span capacity was developed in this paper.The conception of cable supported structure was introduced into floor structure and the span capacity improves largely.However,as an innovative floor structure,some problems needing be solved in the engineering application of CSCFS such as structure static mechanical properties,construction control theory,natural vibration characteristics,dynamic characteristics under human-induced loads,human-induced vibration perception,and vibration control.Based on the above problems,both the numerical analysis and experimental research have been used to conduct a systematic and deep research on the prestress steel structure in this paper.Several research results with great importance in scientific research and engineering application have been obtained:Based on Hebei Normal University Gymnasium,numerical simulation analysis is made aiming at the illumination of mechanical property of CSCFS.The load transfer mechanism of structure is clear,and the effects of structural parameters like pre-tension force,cable sag,cable diameter,strut number,and strut diameter on cable supported composite beam were studied.Besides,the construction process numerical simulation and monitoring of CSCFS were conducted.The reliability of construction process numerical simulation is verified,and the mechanical property of structure in the process of construction is illustrated.Field tests were conducted on the floor of Hebei Normal University Gymnasium,to which the CSCFS was applied for the first time.Two types of experimental tests were conducted: free and human-induced vibration tests.The natural vibration characteristics and the dynamic behavior of the CSBS-CSCFS under different types of human-induced loads were investigated in terms of natural frequency,mode shape,damping ratio,and factors that influence human-induced vibration(e.g.,type of human-induced load,stationary people occupying the floor,synchronism of activities,crowd size,and load frequency).A discussion was also conducted on relationship between vibration and human perception.The finite element model of CSBS-CSCFS was developed,and model updating is conducted based on experimental results.Besides,the structure vibrations under human-induced loads like step,jump,walk,and run were studied.The influences of pre-tension force,cable diameter,sag-span ratio,strut number,steel beam section height,concrete slab thickness on natural vibration characteristics and human-induced vibration of structure were studied.The dynamic performance of CSCFS under human-induced loads after the installation of TMDs and the efficiency of the dynamic control system were discussed through field tests and human perception to vibration.The tests are divided into two phases,namely,free and human-induced vibration tests.The dynamic characteristics of controlled CSCFS and the practical efficiency of TMDs are presented and discussed in terms of natural vibration characteristics,human-induced vibration,human perception to vibration,influencing factors of practical efficiency of TMDs,and characteristics of the effect of TMDs on CSCFS.A simplified model of CSCB was proposed.Using the simplified model and based on Euler-Bernoulli beam theory and some assumptions,the derivation of oscillatory differential equation and natural frequencies calculation formulas of CSCB was conducted.Besides,significant parameters reflecting influences of cable-strut system on natural frequencies of CSCB were extracted and defined.Take a project in which CSCB was applied as engineering background,the natural vibration characteristics of CSCB were studied though formulas calculation,numerical simulation,and field measurement,and the first natural frequency analyzed by the three methods basically meet well with each other.The results verify the validity of simplified model and frequency calculation formulas developed in this paper.