The Influence of Concrete Modeling on Dynamic Response of Railway Bridges
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
This master thesis deals with the dynamic behavior of simply supported reinforced concrete bridges, subjected to both static and dynamic loadings. A numerical model has been created based on the finite element method by using computer software ABAQUS. The behavior of the reinforced concrete bridges is ruled by the nonlinearity of the material. Under the service loads, concrete cracks in some sections and the stiffness of the structures degrades. This phenomenon increases the deflections in the regular structure such as beams and columns of the buildings. In the high-speed line concrete bridges, the stiffness degradation not only increases the forces and displacements but also may increases the probability of the resonance effects in the structure.
Of the primary parameters in design, stiffness is the most difficult to predict and national codes for the design always suggest a lower bound assessment in calculating the bridge stiffness. In order to deal with this issue, many empirical calculations of effective stiffness were proposed and sometimes, only some crude estimations of the stiffness reduction factor are assumed for the design. These methods are verified by experiments and make the design process relatively simple to carry out but none of them describes the actual behavior of the concrete material in bridges under dynamic impacts.
This master thesis investigates the influence of the nonlinear concrete material with the use of “Concrete Damage Plasticity” model in ABAQUS. The model is subjected to both static and dynamic loads and the maximum vertical accelerations of the deck mid-span are evaluated. To overcome the sophistication of non-linear analysis, only a simply supported bridge made of concrete is studied and the bridge is tested under the influence of HSLM-A1 train of the Eurocode running at speeds of 100 to 350 km/h over the bridge.
Place, publisher, year, edition, pages
Trita-BKN-Examensarbete, ISSN 1103-4297 ; 338
Nonlinear finite element analysis, Reinforced concrete beams, Cracking, Effective stiffness, Tension stiffening, Fracture energy, Resonance speed, High-speed trains, bridge dynamics, accelerations
IdentifiersURN: urn:nbn:se:kth:diva-99383ISRN: KTH/BKN/EX-338-SEOAI: oai:DiVA.org:kth-99383DiVA: diva2:542061
Subject / course
Structural Design and Bridges
Degree of Master - Infrastructure Engineering