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Safety Evaluation on the Cable Stayed Bridges for Single Tower Based on Test

Author: WuYiMei
Tutor: HeShuanHai
School: Chang'an University
Course: Bridge and Tunnel Engineering
Keywords: Single-tower cable-stayed bridge Test test Static characteristics Dynamic characteristics Safety Evaluation
CLC: U447
Type: Master's thesis
Year: 2009
Downloads: 92
Quote: 0
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Abstract

With the expansion of the scale of the national transport, increased the pace of bridge construction, large span cable beam composite system by the widespread concern for researchers and designers, one of the single-tower cable-stayed bridge span composite system structure, mechanics complex behavior, the need for such bridge-type test test clearly Sarasota law and the work of state power transmission between the beam test analysis based on single-tower cable-stayed bridge with the appearance of this bridge, the bridge structure geometry situation, cable force parameters, static parameters, dynamic parameters of the safety evaluation, this single tower cable-stayed bridge. The main contents are as follows: (1) the appearance and bridge geometry state test analysis and evaluation. The ① Sarasota and Anchorage Zones tower on the beam and the cable-stayed bridge deck dampers, bearings and expansion joints as well as towers and piers, and the good parts of concrete appearance quality. ② establish the main tower of the bridge, cap and deck control point the GPS measurements outlets, 5 units Ashtech UZ-12 dual-frequency GPS receiver for GPS control network outlets established in accordance with the standard of the Class B network synchronization static relative positioning observation, observation data as the late conservation management and health monitoring technology information. ③ deck continuous vertical curve smooth, Linear good deck. (2) environmental excitation frequency tested 80 full-bridge cable-stayed Permanent Loads Analysis and Evaluation. The test results show that the agreement South Bridge two rows of cable-stayed along the vertical bridge to the Permanent Loads change design values ??and calculate the value of the law, cable downstream corresponding cable force value is close basic rendered symmetry, measured cable force distribution line with the general laws of stay cable. (3) Bridge the analysis and evaluation of the static test. ① steel box girder test the sectional strain measured data regularity better strain of the measured values ??with the theoretical values ??close to the reaction force characteristics of the actual bridge structure the structure measured parameters and structure analysis, the main beam force performance to meet the design requirements; by the main the beam strain measured absolute size point of view, the main beam large safety reserves; shear lag effect of the main beam is smaller impact on the structure; structure in flexible working stage of the main tower. ② test loads, the main tower steel anchor box smaller strain increments, the whole cross-section of the steel anchor box pressure its bending effect is not obvious; the main stress absolute value of the measurement and theory are smaller, so the structural safety; by controlling the height deflection measured value and the theoretical value can be seen stiffening beams in flexible working. ③ deflection measurement values ??along the longitudinal bridge to the laws of distribution law and theory deflection curve control point deflection measured values ??are less than the theoretical value, the description of the the Bridge main beam lateral stiffness larger, there is a strong anti-torsion properties. ④ cable force increments measured value is less than the theoretical value calculated, and the results of the measured values ??evenly distributed than the theoretical value, the main beam stiffness than the theoretical calculation stiffness; test analysis shows that the overall stiffness of the main tower; test load the stiffening girder beam end horizontal displacement under the action of the main conditions are less than the theoretical value, the The stiffening girder horizontal displacement indicators meet the design requirements. (4) of the bridge, the analysis and evaluation of the dynamic test. Measured mode shapes with the theoretical analysis modes basic similarity; five bands ① main bridge priorities in each vibration mode measured results with theoretical calculation of the same as the previous, second-order vibration-based Transverse to, after the third-order mainly to the main beam vertical vibration; ② main bridge five order slightly larger than the measured frequency than theoretical analysis shows that the overall dynamic stiffness of the main bridge.

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