Analytical And Experimental Studies On The Acceleration Response Of Floors Induced By Human Activities

The vibration serviceability issues of the floor system(interaction or not)caused by human-induced load(such as jumping,walking and running)are conducted in this paper,using expaerimental and analytical method.A simplified formula to calculate the peak acceleration,which can provide a reference for engineering design,is proposed.The objectives of the paper are:① Afield test is carried out to investigate the vibration serviceability of the 18.6 m long bays reinforced concrete composite floor.Specifically,ambient and walking(single,double and three person)excitation are performed to capture the dynamic properties(natural frequency,damping ratio and modal shape)and acceleration response(peak and RMS acceleration).The experimental results are used to evaluate the vibration serviceability,to determine the reasonable boundary condition(plate with two opposite edges simply supported and the other two edges clamped),and to verify the interation phenomenon between the human and reinforced concrete composite floor,i.e.,human-structure interaction.② Based on the plate theory,the coupled govern equations of human body subsystem and plate subsystem are established,respectively.This paper adopts a biparametric perturbation method to solve the govern equations,and the perturbation parameters are coefficient ε1(the ratio of unsprung mass ms and sprung mass ma)and coefficient ε3(the ratio of sprung mass ma and reinforced concrete composite floor mass).The perturbation solutions agree well with the experimental results and thus validate the proposed analytical expression.Sensitivity studies using the perturbation solution are also conducted to study the relationship between peak acceleration and walking path,damping ratio and sprung mass ma;and to discuss the effects of the stiffness of reinforced concrete composite floor,uniform load and stiffness of the prestressed floor system for human-structure interaction,which explains the reason for ignoring the interaction.③ The mode superposition method is used to derive the acceleration response of the prestressed concrete floor caused by human-induced load.To calculate the peak acceleration induced by jumping,walking and running conviently for the engineering designer,a simplified formula is proposed by introducing the human-induced factor(coefficients αJ,αw and αR).④Field tests are carried out to investigate the vibration serviceability of three prestressed concrete floor(span 27 m,11.8 m and 18 m)due to jumping,walking and running.The experimnental results are adopted to evaluate the vibration performance of the prestressed concrete,to disscuse the acceleration threshold for the jumping impulse,and to validate the effectiveness of the theoretical solution.Sensitivity studies using the analytical solution are also conducted to discuss the relationship between the attenuation trend induced by jumping and the attenuation direction,damping ratio,exciting position and non-structural member,and to investigate the relationship between the RMS acceleration induced by waling(running)and route,damping ratio and walking(running)rate.Based on the experimental and analytical results,human-induced factor(coefficients αJ,αW and αR)of the simplified formula are proposed.