Damage detection is the most difficult part of structural health monitoring Systems. In order to acquire response information as much as possible, sensors should be carefully placed. Taking Tai Zhou bridge as an example and using the genetic algorithms (GAS), this paper discussed the optimal placement of sensors on suspension bridges for detection of accumulated damage for structural health monitoring systems. After a brief discussion on the classical GAs, and used an example to compare them with the classical GAs. The results show that the generalized GAs are clearly more effective than the classical GAs. On the basis of displacement and curvature modes, three expressions of the fitness were defined for different sensors and tasks. The generalized GAs were used to search the optimal placement of accelerometers and strain gages on the stiffening decks and the towers of Tai Zhou bridge. The results show that the generalized GAs give reliable and stable results with rapid convergence.

As a common type of bridge, the reinforced concrete simply supported T-girder bridges have some usual disease problems such as web vertical cracks, incline cracks near the supports and diaphragm damage, and so on injured by transportation loads. In Shanxi province most of T-girder bridges appear to be under strength for current vehicle loads because most of which are designed by conventional methods and the old codes so it is important to evaluate how the existing damage influence the ultimate bearing capacity of the bridge. The destructive test is a directive mean of verifying the ultimate bearing capacity of bridges. This paper provides details of a destructive load test of a T-girder bridge called Zuojiabao Bridge. It describes the analysis performed prior to testing, aimed at predicting the response of the structure at both serviceability and ultimate states, and discusses the results obtained.The development rule of strain, deflection and crack and the ultimate bearing capacity of the bridge were obtained through the destructive test process. The results showthat although the old T-girder bridge has enough bearing capacity to satisfy the new vehicle standard, it is strongly recommended to strengthen or retrofit the bridge. And the finite element analysis can be effectively applied to the failure analysis of the reinforced concrete T-girder bridge subjected to destructive load.

Concrete slab in the negative moment area of continuous steel-concrete composite beams is prone to crack due to the low tension strength of common concrete, which could result in the decreasing of the strength and durability. To solve this problem, a method of replacing the concrete slab with reactive powder concrete (RPC) slab which is of super high strength, durability, toughness and volume stabilization is presented. According to the constitutive relation and the high tension strength of RPC, the normal section failure mode is defined as the critical crack state, and the calculation formula of ultimate bearing capacity is deduced. Finally, some parameters that influence the ultimate bearing capacity are analyzed, such as the height ratio of RPC slab to whole beam, width ratio of RPC slab to steel beam, and the ratio of reinforcement of RPC slab. Compared with the steel-concrete composite beams, it is indicated that in the precondition of RPC slab unallowable crack in negative moment area, the ultimate bearing capacity of steel-RPC composite beams can still be increased, and the crack resistance, stiffness and durability can all be enhanced greatly.

Based on FEM program ANSYS and the OpenGL graphics, this paper develops the parametric modeling module and the computing module of the multi-tower suspension bridge, this module being embedded into the ANSYS system, and the parametric modeling module parameters can be entered by way of interface, which establish fast a multi-tower suspension bridge model. Calculation module can establish load conditions for the features of road bridge and specifications, in which multiple conditions can be defined and solved automatically. Post-processing part of the solution also for the results of the subtotals and select the output, so that the results of the output and finishing work has become more convenient and easier, and also the results can also be saved in word, excel and other different file types.