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Projects / Programmes source: ARIS

ANALYSIS OF LONG-SPAN BRIDGES CARRYING MOVING VEHICLES EXPOSED TO WIND

Research activity

Code Science Field Subfield
2.05.04  Engineering sciences and technologies  Mechanics  Construction mechanics 

Code Science Field
T230  Technological sciences  Building construction 

Code Science Field
2.03  Engineering and Technology  Mechanical engineering 
Keywords
natural disasters, bridges, collapse, extreme wind
Evaluation (rules)
source: COBISS
Researchers (1)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  27673  PhD Eva Zupan  Mechanics  Head  2011 - 2013  56 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0792  University of Ljubljana, Faculty of Civil and Geodetic Engineering  Ljubljana  1626981  25,761 
Abstract
Development in the design of modern-type long-span bridges for road and rail traffic increases the necessity for more accurate analysis and more precise numerical models of this important structures under extreme loading conditions. In the last decade we were facing extreme winds even in areas where high wind speeds were not typical. The wind represents dynamic load that changes over time and can be only in some special cases adequately modelled as a static load. For proper description of vehicles under wind loads dynamic models need to be employed. Deformable three-dimensional structure under moving vehicle and wind load represents a complex and very demanding problem. The candidate for the project Eva Zupan developed in her PhD thesis numerical model and computer program for coupled dynamic analysis of moving particle on deformable three-dimensional frame. The model is capable of considering arbitrary curved and twisted initial geometry of the beam and takes into account geometrical and material non-linearity of the structure. Coupled with dynamic equations of the structure equations of moving particle are solved. The moving particle represents the dynamic load and varies the mass distribution of the structure and at the same time its path is adapting due to deformability of the structure. So far made studies and comparisons with other authors show excellent agreement with known analytical results for simple problems. The study of more demanding problems has shown that simplified models can underestimate (for 30% and more) the dynamic response of structure with moving mass particle. The previous work thus represents an excellent basis for more sophisticated extension of the present model, where the moving body and the contact between the moving body and the structure would be described more accurately. Our future numerical model will incorporate three-dimensional model of the moving body and non-linear contact conditions between the moving body and the structure, loss of contact and impact of the body on the structure. The wind load will be applied not only to the structure but in the same time also to the moving body. Numerical solution will be based on wide range of differential equations which are coupled in-between but still differ considerably in their nature. Differences between parts of total set of equations might result in several numerical problems. Our numerical model will avoid these problems by employing the weak form of equilibrium equations of the structure, which will result in easier connection between all types of equations and would thus lead to numerically efficient and stable computational process. The structure will be modelled by modern geometrically exact beam elements, moving of the vehicle will be described by dynamic equations of the rigid body and non-linear springs will be used for modelling of contact between the vehicle and the structure. The developed numerical model and the results of prepared computational algorithms will be compared to the results of other authors and to the available experimental results to gain the validity and limitations of the proposed methods. Validated numerical procedures and techniques will serve as theoretical and computational basis for the development and design of new, original, and durable structures carrying moving bodies exposed to wind load. Not very demanding extension with sliding contact constrains would serve as a sufficient and quite accurate model for cranes and various robotic systems. The Republic of Slovenia is planning the construction of the high-speed railway network for which the design and construction of bridges will be necessary together with proper consideration of carrying high-speed body with large mass and surface considering also extreme wind conditions. With developed numerical model we will be able to professionally plan these extremely important engineering facilities.
Significance for science
The development and improvement of numerical methods for dynamic analysis of deformable structures under moving body is a subject of extensive research, which is confirmed by a number of recent papers. Within the project we proposed novel approaches in structural dynamics and developed several new time integrators. The experiences with different solvers and their modification to multiplicative configuration spaces are applicable to various areas of research where the problems are modelled with stiff differential equations and/or rotations. Results and experiences of the project are also a suitable basis for future work in the research group and for cooperation with foreign researchers.
Significance for the country
The development of numerical methods for dynamic analysis of deformable structures under moving body is of utmost importance for the re-assessment of the safety of such engineering structures and in designing the new ones. With the developed model a better understanding of the dynamic response of three-dimensional initially curved and twisted frame structures under moving vehicle and wind loads was achieved. The study of more demanding problems has shown that simplified models can underestimate the response of the structure. The methods and the developed computer program is directly applicable for the analysis of long-span road and railway bridges under moving vehicles and wind loads. Some of the results and the experiences of the project are currently employed in the analysis of several old bridges in Slovenia, where due to novel standards and higher traffic loads re-assessment is needed.
Most important scientific results Annual report 2011, 2012, final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Annual report 2011, 2012, final report, complete report on dLib.si
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