Structural integrity verification of cable stayed footbridge based on FEM analyses and geodetic surveying techniques

Abstract

This paper presents the mathematical models developed for the design of a pedestrian, cable stayed bridge, the geodetic monitoring procedures and their detailed cross-comparisons and analyses undertaken during the phases of construction and at commissioning stage. Because of the asymmetric design, the relative flexibility of the pylons, the eccentric positioning of the central joint and the off-plane low angles of the cables, a multi-sensor, event based geodetic monitoring scheme was adopted to assess the structural integrity of the bridge. During construction, the bridge kinematics were measured along both sides of the deck and at selected points on the pylon facades using a digital level and a high accuracy total station used in metrology respectively. At a commissioning stage, a number of load test series were undertaken using conventional geodetic techniques and a tactical grade Inertial Measurement Unit (IMU). Analysis confirmed the overall mathematical modelling assumptions made for the individual stages of construction and for the completed structure. However, analysis also revealed the increased structural rigidity of the structure. This particularly applies for the torsional stiffness of the deck that exhibits low (by a factor of 0·5) rotation angles compared to those obtained from the analytical models.