Load Test Research On A Concrete Cable-stayed Bridge With Single Cable Plane

Testing contents and methods are summarized for cable-stayed bridge. A Prestressed concrete cable-stayed bridge with single central cable plane and single pylon and is used as an example. Load test project is set out for the bridge final acceptance, including static load test, dynamic load test, ambient vibration test and test for the bridge completion state.The preparatory work and test process are introduced in the static load test as well as evaluation method of the bridge bearing capacity. The stress and strain of all the test sections is tested on the main beam and the main pylon. The main beam deflection and the main tower setoff are recorded in the test. The increment of cable force is measured under vehicle loads in test. The environment temperature is monitored at the same time. The checkout coefficients and the residual deformation are analyzed for the tested cable-stayed bridge. The main bridge rigidity is large enough to resist the design load which deformation complies with plane assumption. The results of static load test show that the tested bridge have enough bearing capacity and serviceability to undertake the highway load of grade one.The barrier-free driving test and obstacles test are done on the tested bridge as well as the braking test. The dynamic strain and its increment are measured on the main beam. The dynamic responses of the tested bridge are compared in the three tests to obtain the bridge impact resistance. The results of the dynamic load test indicate that the dynamic strain increments are relatively low under moving vehicle load on the tested cable-stayed bridge. Therefore, the bridge has enough rigidity reserve to resist the deformation under design load.The vibration properties were tested in ambient vibration test including vibration modes, frequencies and damping ratio of the tested cable-stayed bridge, which were compared with theoretical values. The results manifest that the test frequencies are larger than the theoretical values and the damping ratio is lower than 1%. Hence, the actual stiffness is larger than the design value.The bridge deck alignment and dead load cable force were tested in the test for bridge completion state. The results show that the deck alignment is smooth and the altitude differences on both sides are basically consistent. The tested cable forces under dead load are consistent with the design ones. The bridge final completion state is satisfied with design need.Generally, the bearing capacity and serviceability are satisfied with the design demand according to the static load test and dynamic load test.