| The assessment of bridges load-bearing capacity through structural analysis is one of the most common methods around the world, due to acceptable results and low-cost. The bridges load-bearing capacity is affected by the increases in the number of vehicles and in load of trucks, damage to member, and deterioration.In China, Ministry of Communications has been developing a new bridges carrying capacity assessment method "Specification for Inspection and Evaluation of Load-bearing capacity of Highway Bridge" JTG Method, due to the development in bridge inspection technology. Previously at1989, China’s Ministry of Communications issued "Carrying-capacity of Highway Bridge Evaluation Methods (Trial)" Trail Method, which is still used to date.This research was carried out on seven bridge samples from SHAANXI province. These bridges were inspected, tested, and analyzed to assess their load-bearing capacity. The assessment was conducted under three methodologies Chinese, American, and British. To evaluate the new Chinese method, the carrying capacity results calculated by new Chinese JTG Method were compared with old one Trail Method. The comparison indicated that the new JTG Method produced lower carrying capacity assessment results than the old Trail Method, In general. The carrying capacity decreases ranged between (4-10) percent.Another comparison was made between AASHTO Load Factor Rating (LFR) and Load and Resistance Factor Rating (LRFR) methodologies. Both of these methods are still used in United State. The bridges rating results indicated that the LRFR produced a lower bridge rating factor than the LFR methodology, the decreases are ranged between (17-38) percent.Comparisons were additionally made between the new Chinese JTG Method and American (LFR, LRFR). and British (BD21) methodologies. These comparisons are provided two important findings. First, it can be observed that the BD21method produced a slightly lower control carrying capacity assessment results than JTG Method. Second, LFR and LRFR produced lower control carrying capacity assessment results than the JTG Method for unsatisfactory carrying capacity bridge samples. Otherwise, the JTG Method had carrying capacity results lower than LFR and LRFR. Load test was carried out on the bridge samples to assess the bridges carrying capacity from load test results. The load test carrying capacity results were compared with calculated carrying capacity under American (LFR, LRFR) and Chinese (Trail Method, JTG Method). For the JTG Method, the majority of calculated control carrying capacity results are underestimated the load test carrying capacity results, with decreases range between (0-13) percent. In addition, the calculated carrying capacity under Chinese JTG Method and American LRFR are good correlated to the load test carrying capacity results. This indicates that, these two methods had a good estimated of bridge carrying capacity. |
