Aiming to Ronggui Bridge (RGB) on Guangzhou-Zhuhai Intercity Rapid Rail Transit (GZIRRT), long term deformation control of long-span pre-stressed concrete continuous rigid frame bridge with ballastless track was studied. Comparing with the non-controlled deformation, extend track laying six months later after bridge construction, reserve 48 post-tensioned cables in middle spans and tension 12 external tendons after tracking laying were all effective in decreasing the long term deformation of RGB with individual application. Taking bridge construction and railway service in consideration, applying the foregoing three measures in combination, deformation of RGB 20 years later after track laying was effectively controlled within 12.8mm in the side spans and 21.9mm in the middle spans, which is less than the deformation limitation of bridges with ballastless track. The combined measure has been adopted in the actual construction of RGB.
Orthotropic monolithic steel bridge deck system stiffened by U rib is very fit for high-speed railway steel bridges because of its excellent mechanical behaviors. Thickness of flange is a very important parameter of U rib and has influence on mechanical behaviors of orthotropic monolithic steel bridge deck system. Based on the engineering practice of Anqing Yangtze River Railway Grand Bridge, the kind and the extents of influences of thickness of flange of U rib on mechanical behaviors of orthotropic monolithic steel bridge deck system are studied with finite element analysis. The results show that thickness of flange of U rib has relative large positive influences on rigidity, strength and stability of orthotropic monolithic steel bridge deck system. 14~18mm is the appropriate range of thickness of flange of U rib for high-speed railway steel bridges.
The seismic performance of reinforced concrete(RC) columns is one of the controlling factors of the shock resistance for RC frame structures and bridges under seismic loads. Due to the complicated material behavior and complex external force during the earthquake, an accurate simulation of the mechanical performance under seismic loads demands more precisions for the hysteresis constitutive laws of materials. In this paper, based on the fiber cross-section model, adopting revised Kent-Park model for concrete and Legeron model for steel reinforcement, programming the UMAT material subroutine, FEM software ABAQUS is used to simulate a RC column mentioned in a research. It’s results are found agreed well with the test results.
Abstract. In the presented paper, reverse push-out test method was put forward and applied in the ultimate bearing capacity experiments of studs with concrete slab in tension. Ultimate bearing capacity experiments were carried out on 22 reverse push-out specimens composed of C50 or C40 concrete, 14MnNbq steel girder and Φ22studs. Results showed that ultimate bearing capacity of studs, pu, in tensile concrete slab is controlled by concrete failur, concrete strength, studs arragement and reinforcement ratio are the main influence factors of pu. Compared with that in compressive concrete, pu of Φ22 studs in tensile concrete is reduced about 30% averagely. According to the test results, a fitted load-slip relationship curve and a regression formula of pu for studs in tensile concrete were put forward, calculated results were in good agreement with the test results.
Taking Jinan Yellow River Bridge as an example, using 3D finite element method, displacement and behavior of four-line high-speed railway bridge with two main trusses, K-shaped brace and middle suspender is studied. The results show that transversal wave of displacement of floor system is significant, and the difference of the displacement in transversal direction reaches 6 mm. The causes includes: large distance between two main trusses, large stiffness of stringers, longitudinal stiffeners and crossbeams, weak transversal stiffeners which do not connect to lower chords. About 90% of the loads are transferred to the crossbeam through path 1 and about 60% to 80% of these loads through K-shaped braces. Less than 10% of the loads transferred to lower chords through path 2.
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