Experimental Analysis And Research On The Mechanical Behavior Of Steel Box Girder Pedestrian Bridge

Pedestrian bridge provides a good solution to ease traffic congestion and convenience of pedestrians.Form with the development of the society,the structure of the pedestrian bridge is becoming more and more diverse.Steel box girder pedestrian bridge is one of the main structure form at present,and its material light some,mainly as large and medium-sized bridge.Safety and mechanical properties of the pedestrian bridge is particularly important in the design,operation and maintenance.Combining with the actual project,mechanical behavior of 10 steel box girder pedestrian bridge is systemic analyzed and researched,the main contents are as follows.1.The study of steel box girder pedestrian bridge mechanical performance is analyzed and researched,involving the static performance and dynamic performance of the status quo,point out the insufficiency that in the systematic study of the steel box girder pedestrian bridge mechanical performance,and the lack of rail horizontal thrust test research.2.Static test of 10 steel box girder pedestrian bridges is systematic analyzed.Test preparation needed for the analysis of static test and requirements are summarized,including the selection of test method,test control section as well as the measuring point arrangement.This paper expounds in detail the control elements in the process of using the finite element software Midas,including water bag static load weight and theory calculation control values.The results show that the calibration coefficient and relative residual of the 10 steel box girder pedestrian bridge strain and deflection are all conformed to the requirements of the specification,and the material selection and structure by this kind of steel box girder pedestrian bridge meet the requirements under the design load bearing capacity.3.Dynamic performance index of 10 steel box girder pedestrian bridge is analyzed.The main content of the basis of test,test section,the main test instruments and test parameters choice are studied.Through the environment vibration experiment and barrier-free running test,vibration fundamental frequency and the maximum response speed under human movement are respectively tested.The experiment result shows that the steel box girder of pedestrian bridge which span is greater than or close to 40 m,its vertical lowest natural frequencies do not meet the specification requirements of the greater than 3 Hz,and under the condition of large span,the maximum acceleration response is higher,and the vertical lowest natural vibration frequency is inversely proportional with the span,positively related the depth-span ratio,proposed to design a multi-span bridge or increase the depth-span ratio,so as to add a tuned mass damper to enhance the overall stiffness of the bridge.4.Rail horizontal thrust of 10 steel box girder pedestrian bridge is tested and analyzed.Study the test required for preparation and requirement,including the selection of instruments and equipment,the principle of loading and loading method.According to the pedestrian bridge railings structure form and material form,using Midas finite element to analysis the maximum horizontal load values and the corresponding horizontal displacement theorytic value.Based on the principles of load level 4 loading tests are carried out.Through analyzing the test results of research,confirmed that the candidate railing under this kind of material and sectional form,does not meet the requirements of design load of 2.5 kN/m.